CN111050448B - Ripple removing circuit, ripple removing chip and electronic product - Google Patents
Ripple removing circuit, ripple removing chip and electronic product Download PDFInfo
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Abstract
The invention provides a ripple removing circuit, a ripple removing chip and an electronic product, wherein a sampling module of the ripple removing circuit can generate a sampling signal which follows dynamic change of a driving current based on the size of a load (namely the size of the driving current), so that a reference trigger module can generate a trigger voltage which follows the dynamic change of the driving current according to the sampling signal which dynamically changes and a corresponding fixed reference voltage, and further the ripple removing module controls a constant current source according to the trigger voltage and the voltages at two ends of the constant current source so as to quickly remove ripples in the driving current, so that the driving current is near-direct current, and the problems of low system loop bandwidth, low system loop response speed, easy occurrence of current overshoot and the like in the processes of quick startup and shutdown and small-angle dimming are solved.
Description
Technical Field
The invention relates to the technical field of current ripple removal, in particular to a ripple removal circuit, a chip and an electronic product.
Background
LEDs (Light Emitting diodes) are used in a variety of electronic applications, such as: architectural lighting, automobile headlights and taillights, backlights for liquid crystal display devices including personal computers and high definition televisions, and flashlights. LEDs have significant advantages over conventional light sources such as incandescent and fluorescent lamps, including high efficiency, good directionality, color stability, high reliability, long lifetime, small volume, and environmental safety. LEDs are current-driven devices, and therefore, regulating the drive current through an LED is an important control technique. Referring to fig. 1, currently, an APFC (active power factor correction) LED driving chip or a general linear LED driving chip is generally adopted as an LED driving device 1 to drive an LED2 to emit light, specifically, the LED driving device 2 generally includes a power converter (not shown) and a constant current driving control chip (not shown), the rectifying circuit 1 rectifies the connected AC power and outputs the rectified AC power to the LED driving device 2, the power converter in the LED driving device 2 is located on a circuit loop where an LED3 is located, converts the high-voltage dc power output by the rectifying circuit 1 into low-voltage dc power to be provided to an LED3, and the constant current driving control chip in the LED driving device 2 controls the magnitude of a driving current signal I _ LED output by the power converter to drive an LED3 to emit light. The driving current signal I _ LED output by the LED driving apparatus 1 includes a current ripple with a power frequency, which is generally a low-frequency ripple of 100Hz or 120Hz, so that the problem of stroboscopic (flashing) of the LED occurs. For example, if the input source frequency is 50Hz, the current I _ LED output by the LED driving device 2 has a ripple of 100Hz, that is, in this case, the current I _ LED flowing through the LED3 also has a ripple of 100Hz, so that the light emitted by the LED3 has a stroboscopic effect of 100 Hz. Although the human eye can hardly detect the low-frequency stroboflash, the human eye can cause visual nerve fatigue and harm human health under the illumination environment for a long time. Therefore, in high-end applications, it is necessary to eliminate current ripples contained in the driving current supplied to the LED by the LED driving apparatus.
However, although the current ripple-removing or strobe-removing circuit technology can meet the requirement of full-load application, when a fast startup and shutdown is required, the problems of low loop bandwidth, slow system loop response speed, easy occurrence of current overshoot and the like exist, and the slow system loop response speed can cause the LED to show a severe fade-on phenomenon, experience is very poor, and the current overshoot problem is that an instant current of a parameter which is output to the LED by a driving device and used for controlling the LED to work exceeds a full-load current which can be borne by the LED, so that the LED flickers at the starting instant and even goes out directly. And these problems will be more serious in the scr dimming application system, because, in the scr dimming application system, the voltage and current of the LED are closely related to the phase angle of the scr dimmer, the phase angle of the scr dimmer varies from 0 degree (close to 0 degree) to 180 degrees, and in order to filter the jitter caused by the dimming of the scr dimmer, the jitter has a lower frequency than the general low frequency ripple (power frequency ripple), and the loop bandwidth of the system needs to be further reduced, which is usually reduced to below 0.1 Hz. Under the condition, when the silicon controlled dimmer realizes small-angle dimming, the loop is very slow to establish, the light-emitting brightness of the LED cannot quickly respond to the dimming operation of the silicon controlled dimmer, and the condition that the current flowing through the LED overshoots easily is caused.
In addition, the above-described problems also exist in systems where improvement of loop dynamic response characteristics is required.
Disclosure of Invention
The invention aims to provide a ripple removing circuit, a ripple removing chip and an electronic product, which can eliminate ripples in driving current so as to solve the problems of low loop bandwidth, low system loop response speed, easy occurrence of current overshoot and the like during fast startup and shutdown and small-angle dimming.
In order to achieve the above object, the present invention provides a ripple removing circuit, which is disposed on a line of a driving device for supplying a driving current to a load, wherein the driving current includes a ripple, the ripple removing circuit including:
a constant current source connected in series with the load, the driving current flowing through the constant current source and the load;
the sampling module is used for sampling the driving current to generate a sampling signal which dynamically changes along with the driving current;
the reference trigger module is used for providing at least one fixed reference voltage, and generating a corresponding reference voltage and a trigger voltage which dynamically changes along with the driving current according to the sampling signal and the corresponding fixed reference voltage; and the number of the first and second groups,
and the ripple removing module is used for controlling the constant current source according to the trigger voltage, the reference voltage and the voltage at two ends of the constant current source so as to remove ripples in the driving current.
Optionally, the trigger voltage output by the reference trigger module is the sum of a fixed voltage and a voltage proportional to the driving current before and after the driving current is stabilized; or the trigger voltage output by the reference trigger module before the driving current is stabilized is the sum of a fixed voltage and a voltage proportional to the driving current, and the trigger voltage output after the driving current is stabilized is the sum of the peak value of the voltage at two ends of the constant current source and another fixed voltage; or, the trigger voltage output by the reference trigger module before the driving current is stabilized is a sum of a fixed voltage and a voltage proportional to the driving current, and the trigger voltage output after the driving current is stabilized is a sum of a fixed voltage, a voltage proportional to the driving current and a voltage proportional to a peak value of a voltage across the constant current source.
Optionally, the reference triggering module includes:
the first fixed reference voltage unit is used for generating a first fixed reference voltage and providing the first fixed reference voltage as a reference voltage to the ripple removing module;
a second fixed reference voltage unit for providing a second fixed reference voltage; and the number of the first and second groups,
the first adder is used for superposing the second fixed reference voltage and the sampling signal to obtain the trigger voltage;
the ripple removing module is used for controlling the constant current source according to the trigger voltage, the voltage at two ends of the constant current source and the first fixed reference voltage.
Optionally, the reference triggering module includes:
a first fixed reference voltage unit for providing a first fixed reference voltage;
the second adder is used for superposing the first fixed reference voltage and the sampling signal to obtain a dynamic reference voltage which changes along with the sampling signal;
a second fixed reference voltage unit for providing a second fixed reference voltage;
the first adder is used for superposing the second fixed reference voltage and the sampling signal to obtain the trigger voltage;
the ripple removing module is used for controlling the constant current source according to the trigger voltage, the voltage at two ends of the constant current source and the dynamic reference voltage.
Optionally, the reference trigger module further includes a trigger voltage adjusting unit, configured to collect a peak value of the voltage across the constant current source, and adjust the trigger voltage output by the first adder to a sum of the peak value of the voltage across the constant current source and another fixed voltage after the driving current collected by the sampling module is stable, or to a sum of a fixed voltage, a voltage proportional to the driving current, and a voltage proportional to the peak value of the voltage across the constant current source.
Optionally, the ripple removal module comprises:
the comparator is used for comparing the trigger voltage with the voltage at two ends of the constant current source and outputting a corresponding trigger signal according to the comparison result;
the error amplifier is used for outputting an analog compensation signal according to the difference between the voltage at the two ends of the constant current source and the reference voltage provided by the reference triggering module;
the operational amplifier is used for controlling the constant current source according to the received analog compensation signal so as to remove ripples in the driving current;
the error amplifier also receives the trigger signal output by the comparator and accelerates the change of the output analog compensation signal according to the trigger signal; or, the output end of the comparator and the output end of the error amplifier are coupled and then connected to the input end of the operational amplifier, so as to accelerate the change of the analog compensation signal to be received by the operational amplifier according to the trigger signal.
Optionally, the error amplifier is a digital error amplifier implemented in the form of a digital circuit, or an analog error amplifier implemented in the form of an analog circuit.
Optionally, when the error amplifier is an analog error amplifier, the ripple removal module further includes a capacitance to ground or an integrator; one end of the ground capacitor is connected with the output end of the error amplifier, and the other end of the ground capacitor is grounded; the integrator is connected between the output of the error amplifier and the input of the operational amplifier.
Optionally, the error amplifier and the comparator are respectively integrated with a detection circuit for detecting the voltages at two ends of the constant current source; or, the ripple removing circuit further includes a detection module disposed outside the sampling module and the ripple removing module and configured to detect a voltage across the constant current source, where the detection module includes a first voltage-dividing resistor and a second voltage-dividing resistor, one end of the first voltage-dividing resistor is connected to a node where the constant current source is connected to the load, the other end of the first voltage-dividing resistor is connected to one end of the second voltage-dividing resistor, the other end of the second voltage-dividing resistor is grounded, and one end of the first voltage-dividing resistor connected to the second voltage-dividing resistor is at least configured to provide a corresponding voltage signal to the comparator and the error amplifier.
Optionally, the sampling module includes a current monitoring unit and a current sampling unit, and the load, the constant current source, the current monitoring unit and the current sampling unit are sequentially connected to form a series circuit; the current monitoring unit is used for monitoring the driving current flowing through the series circuit; the current sampling unit is used for sampling the driving current monitored by the current monitoring unit so as to output the sampling signal to the reference triggering module.
Optionally, the current monitoring unit comprises a variable resistor or a fixed resistor or a transistor operating in the linear resistance region.
Optionally, when the current monitoring unit includes a variable resistor or a transistor operating in a linear resistance region, the sampling module further includes a sampling control unit for adjusting a resistance value of the variable resistor or the transistor operating in the linear resistance region according to the analog compensation signal.
Optionally, the current sampling unit includes a multiplier, and the multiplier is configured to multiply the driving current monitored by the current monitoring unit by K and output the multiplied driving current as the sampling signal to be transmitted to the reference trigger module, where K is a positive number that is not equal to 0 or 1.
Optionally, the constant current source comprises at least one constant current switch having a control terminal, an input terminal of a switch path, and an output terminal of the switch path; the input end of a switch path of the constant current switch is at least connected with one end of the load and the ripple removing module, the output end of the switch path of the constant current switch is connected with the input end of the sampling module or grounded, and the control end of the constant current switch is connected with the output end of the ripple removing module.
Optionally, in the ripple removing circuit, at least the constant current source, the reference trigger module and the ripple removing module are integrated in the same chip.
Based on the same inventive concept, the invention also provides a ripple removing chip which comprises the ripple removing circuit.
Based on the same inventive concept, the invention also provides an electronic product, comprising:
the rectifying circuit is used for rectifying the accessed alternating current and outputting the alternating current as direct current;
a load;
the driving device is used for converting the direct current into driving current with ripples so as to drive the load to work; and the number of the first and second groups,
according to the ripple removing circuit, the ripple removing circuit is arranged on a line of the driving device for supplying the driving current to the load and is used for removing ripples in the driving current.
Compared with the prior art, the technical scheme of the invention has the following beneficial effects:
1. in the technical scheme of the invention, the sampling module can generate a sampling signal which is dynamically changed along with the driving current based on the size of the load (namely the size of the driving current on a line where the load is located), so that the reference trigger module can generate a trigger voltage which is dynamically changed along with the driving current according to the dynamically changed sampling signal and corresponding fixed reference voltage, and further the ripple removing module controls the constant current source according to the trigger voltage and the voltages at two ends of the constant current source so as to remove ripples in the driving current and enable the driving current to be near-direct current. Therefore, when the system needs to trigger a loop accelerating condition, the corresponding trigger voltage can be dynamically adjusted based on the load size, when the load is small, the trigger voltage is set to be low, when the load is large, the trigger voltage is set to be high, so that the system can trigger the loop accelerating function earlier when the small current or the small angle is started, and the problems of low system loop bandwidth, low system loop response speed, easy occurrence of current overshoot and the like in the processes of quick startup and shutdown and small-angle dimming are solved.
2. The technical scheme of the invention is suitable for various applications requiring loop dynamic response characteristic improvement, and is particularly suitable for general linear LED driving application and silicon controlled rectifier dimming application so as to remove low-frequency ripples in driving current provided by an LED driving device to an LED and eliminate the problems of LED stroboscopic and slow response of dimming operation.
Drawings
Fig. 1 is a schematic diagram of a typical LED product system.
Fig. 2 is a schematic structural diagram of a ripple removing circuit applied to an LED product system according to an embodiment of the present invention.
Fig. 3 is a schematic diagram comparing the relationship between the voltage across the constant current source and the driving current before and after applying the ripple removing circuit of the present invention to the LED product system.
Fig. 4 to 14 are schematic circuit designs of the ripple removing circuit according to various embodiments of the present invention.
FIG. 15 shows the trigger voltage V of an embodiment of the present inventionOVPAn example of dynamic variation with drive current I _ LED.
Fig. 16 is a schematic circuit structure diagram of an electronic product according to an embodiment of the invention.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings in order to make the objects and features of the present invention more comprehensible, however, the present invention may be realized in various forms and should not be limited to the embodiments described above. It is to be noted that the drawings are in a very simplified form and are all used in a non-precise ratio for the purpose of facilitating and distinctly aiding in the description of the embodiments of the invention.
Before describing the specific design of the ripple removing circuit of the present invention in detail, we first explain the design principle of the ripple removing circuit of the present invention with reference to fig. 2 to 4, and the details are as follows:
please refer toReferring to fig. 2 and 4, the ripple removing circuit 4 of the present invention is connected in series on a line on which the driving device 2 supplies the driving current I _ LED to the load 3 (such as an LED lamp), and may be connected in series between the negative terminal of the load 3 and the ground, or between the driving device 2 and the positive terminal of the load 3, where the ripple removing circuit 4 is connected in series between the negative terminal of the load 3 and the ground in the case shown in fig. 2. The driving device 2 inputs a driving current I _ LED to the load 3 to drive the load 3 to operate. The driving current I _ LED is a current signal containing a ripple (i.e., a low frequency component), thereby also causing a voltage across (i.e., a Drain terminal voltage, i.e., a voltage of a negative terminal Drain of the load 3 in fig. 2) V of the constant current source M1 in fig. 4DrainAlso contains ripples. The ripple removing circuit 4 may sample the driving current I _ LED or the voltage V across the constant current source M1 in fig. 4DrainAnd generating a corresponding analog compensation signal COMP to filter the low-frequency signal in the driving current I _ LED, thereby keeping the voltage at the two ends of the load 3 basically unchanged, so that the driving current I _ LED is a near-direct-current signal.
Referring to fig. 3 and 4, in order to enable the ripple removing circuit 4 to effectively remove the low-frequency ripple, it is necessary to enable the generated analog compensation signal COMP to change quickly, and to respond to the change of the driving current I _ LED and the like quickly, and when the system is stable, the voltage ripple in the analog compensation signal COMP is the voltage VDrainVoltage ripple in the capacitor. Therefore, when the system is in the processes of fast startup and shutdown, small-angle dimming and the like, the driving current I _ LED is slowly increased at the beginning, and the trigger voltage V isOVPWith the drive current I _ LED slowly increasing, the control voltage VDrainIncreases with the increase of the driving current I _ LED when the trigger voltage V is increasedOVPA trigger condition is reached (e.g. V)OVPIs equal to voltage VDrain) Then, the ripple removing circuit 4 controls the driving current I _ LED to increase rapidly, and the trigger voltage V is simultaneouslyOVPAlso increases with the rapid increase of the driving current I _ LED, which in turn can increase the system loop response speed and rapidly remove the ripple in the driving current I _ LED, thereby causing the driving current I _ LED and the voltage V to increaseDrainCan be stabilized quickly, and simultaneously, the effect of ensuring the ripple wave removal and the optimization of the efficiency can be removed. As can be seen from FIG. 3, the contacts provided in the prior artVoltage V of generatingOVPSo that the driving current I _ LED overshoots in the processes of quick startup and shutdown and small-angle dimming (namely, in the area on the left side of the rightmost vertical dotted line), and then the driving current I _ LED can fall back to the current of stable operation of the system, and VDrainThe peak value in the processes of quick startup and shutdown and small-angle dimming is higher along with the overshoot of the driving current I _ LED, and the response speed of a system loop in the processes of quick startup and shutdown and small-angle dimming is lower; compared with the prior art, the ripple removing circuit can enable the system to trigger the loop to be accelerated earlier, the response speed of the loop of the system is high (the left vertical dotted line is much ahead of the right vertical dotted line) in the processes of quick startup and shutdown and small-angle dimming, and the driving current I _ LED and the voltage V at two ends of the constant current sourceDrainCan be stabilized quickly, and the problems of current overshoot, fluctuation and the like can not occur in the stable working stage of the system.
Based on the above principle, the present invention provides a ripple removing circuit, which can accelerate the trigger loop (i.e. accelerate the change of the analog compensation signal COMP) of the trigger voltage VOVPThe variation of the driving current I _ LED is changed along with the variation of the driving current I _ LED, so that the variation of an analog compensation signal COMP is accelerated in the processes of quick startup and shutdown or small-angle dimming and the like, the system further reaches a triggering condition earlier, and the voltage V at two ends of a constant current source is controlledDrainThe voltage (namely the voltage at the negative terminal of the load 3) is not increased too much, and the system stabilization time is greatly reduced, so that the problems of low loop bandwidth, low system loop response speed and possible current overshoot in the small-angle dimming and fast startup and shutdown processes can be well solved.
The specific circuit design and the technical effects brought by the degripping circuit of the present invention will be described in detail below with reference to the specific embodiments shown in fig. 2 to 16.
Example one
Referring to fig. 2 and 4, the present embodiment provides a ripple removing circuit 4 disposed on a line of a driving device 2 for transmitting a driving current I _ LED to a load 3, where the driving current I _ LED includes a low-frequency ripple of 100Hz to 120 Hz. The load 3 in this embodiment may be one LED lamp, or may be an LED lamp string formed by connecting at least two LED lamps in series and/or in parallel. The driving device 2 is an LED driving device, and includes a power converter 21, a power switching tube Q0, a sampling circuit (not shown), and a driving chip 22. The power converter 21 is configured to convert a voltage of the direct current output from the rectifier circuit 1 at the previous stage into an operating voltage required by the load 3. The power switch Q0 may be a MOS transistor, and the sampling circuit includes a sampling resistor Rcs connected in series with the switching path of the power switch Q0 (i.e., the source terminal of the power switch Q0), and is configured to sample a voltage signal Vcs on the switching path of the power switch Q0. The driving chip 22 may be a linear driving chip or an active power factor correction driving chip, the driving chip 22 generally has a power input pin Vin coupled to the output terminal of the rectifying circuit 1, a sampling pin CS connected to the source terminal of the power switch Q0, a ground pin GND, a pin Vcc connected to the drain terminal of the power switch Q0, and a pin connected to the gate terminal of the power switch Q0, and the driving chip 22 is configured to control the on/off of the power switch Q0 according to the voltage signal Vcs, so as to control the output of the power converter 21, so as to drive the load 3 to operate.
Referring to fig. 4, the ripple removing circuit 4 of the present embodiment includes a constant current source M1, a ripple removing module 40, a sampling module 41, and a reference triggering module 42. The constant current source M1 is connected in series with the load 3, and the driving current I _ LED flows through the constant current source M1 and the load 3. The sampling module 41 is configured to sample the driving current I _ LED to generate a sampling signal that dynamically changes along with the driving current I _ LED, where the sampling signal is K × I _ LED in this embodiment, and K is a positive number that is not equal to 0 or 1. The reference trigger module 42 is configured to provide at least one fixed reference voltage, and generate a trigger voltage V that dynamically changes with the driving current I _ LED according to the sampling signal and the corresponding fixed reference voltageOVP. The ripple removing module 40 is used for removing the ripple according to the trigger voltage VOVPThe voltage (i.e. V) across the constant current source M1DrainAnd the reference voltage provided by the reference triggering module 42 controls the constant current source M1 to remove the ripple in the driving current I _ LED.
Specifically, in the ripple removing circuit 4 of this embodiment, the constant current source M1 is a constant current switch, and the constant current switch may be selected from one of a PMOS transistor, an NMOS transistor, an NPN transistor, a PNP transistor, a JFET, and an IGBT, in this case, the constant current source M1 has a control terminal (for example, a gate terminal of the NMOS transistor), an input terminal of a switch path (for example, a Drain terminal of the NMOS transistor), and an output terminal of the switch path (for example, a source terminal of the NMOS transistor), the control terminal of the constant current source M1 is connected to the ripple removing module 40 and controlled by the ripple removing module 40, and the input terminal of the switch path of the constant current source M1 is connected to a negative terminal Drain (hereinafter, referred to as a Drain terminal) of the load 3; the sampling module 41 comprises an adjustable resistor Rp and a current sampling unit U2, wherein the output end of the switching path of the constant current source M1 is connected to the upper end of the adjustable resistor Rp (i.e., the input end of the sampling module 41); the reference trigger module 42 includes a first fixed reference voltage unit REF1, a second fixed reference voltage unit REF2, and a first adder U1; the de-ripple module 40 comprises a digital error amplifier DEA, a comparator CMP and an operational amplifier OP.
The specific circuit connections in the sampling module 41 are as follows: the adjustable resistor Rp and the current sampling unit U2 are connected in series to a switch path of the constant current source M1, that is, one end of the adjustable resistor Rp is connected with an output end of the switch path of the constant current source M1, the other end of the adjustable resistor Rp is connected with one end of the current sampling unit U2, the other end of the current sampling unit U2 is grounded to GND, and an output end of the current sampling unit U2 is connected with an input end of the first adder U1. The adjustable resistor Rp serves as a current monitoring unit, and can adjust a resistance value (i.e., impedance) of a line on which the load 3 is located according to an analog compensation signal COMP generated by the digital error amplifier DEA to adjust and monitor the magnitude of the driving current I _ LED, and the current sampling unit U2 is configured to sample the driving current I _ LED to generate the sampling signal. In this embodiment, based on VOVPAnd in proportion to the driving current I _ LED on the line on which the load 3 is located, the selected current sampling unit U2 includes a multiplier, and the multiplier is configured to multiply the driving current I _ LED on the line on which the load 3 is located by K and output the multiplied current to the sampling signal K × I _ LED, so as to transmit the sampling signal K × I _ LED to one input end of the first adder U1 of the reference trigger module 41, where K is a positive number not equal to 0 or 1. Thus, the reference trigger module 42 can be made to simply trigger the voltage VOVPIs set to a second fixed reference voltage (not shown, hereinafter referred to as V)REF2) Adding a voltage proportional to the current I _ LED of the load 3, i.e. VOVP=VREF2+K*I_LED,VOVPThe curve as a function of I _ LED is shown in fig. 15.
It should be noted that the adjustable resistor Rp, the current sampling unit U2 and the load 3 in this embodiment are substantially connected in series, and therefore, the current sampling unit U2 can collect the driving current I _ LED on the line where the load 3 is located. In addition, although the circuit part of the ripple removing module 40 for changing the resistance value of the adjustable resistor Rp is not shown in the present embodiment, a person skilled in the art may refer to the sampling control unit K × COMP in the ripple removing circuit 4 shown in fig. 8, and may select any known suitable circuit design to implement the control and adjustment of the adjustable resistor Rp by the ripple removing module 40.
With continued reference to fig. 4, the specific circuit connections in the reference trigger module 41 are as follows: the output terminal of the first fixed reference voltage unit REF1 is used as an output terminal of the reference trigger module 41, and is connected to an input terminal of the digital error amplifier DEA (for example, the inverting input terminal of the digital error amplifier DEA), the output terminal of the second fixed reference voltage unit REF2 is connected to an input terminal of the first adder U1, another input terminal of the first adder U1 is connected to the output terminal of the current sampling unit U2, and the output terminal of the first adder U1 is used as another output terminal of the reference trigger module 41, and is connected to an input terminal of the comparator CMP (for example, the inverting input terminal of the comparator CMP). Wherein the first fixed reference voltage unit REF1 is used for generating a first fixed reference voltage (not shown in the figure, hereinafter referred to as V)REF1) And supplies it as a reference voltage to a digital error amplifier DEA; the second fixed reference voltage unit REF2 is used for generating and providing a second fixed reference voltage VREF2A first adder U1 for adding the second fixed reference voltage VREF2And the sampling signal K I _ LED is superposed to obtain a trigger voltage V which dynamically changes along with the driving current I _ LEDOVP,VOVP=VREF2+K*I_LED。
In this embodiment, the specific circuit connections in the ripple removing module 40 are as follows: one input terminal (for example, the inverting input terminal of the comparator CMP) of the comparator CMP is connected to the output terminal of the first adder U1, the other input terminal (for example, the non-inverting input terminal of the comparator CMP) of the comparator CMP is connected to the Drain terminal, the output terminal of the comparator CMP is connected to the third input terminal (for example, a dynamic reference voltage terminal of the digital error amplifier DEA), the second input terminal (for example, the inverting input terminal of the digital error amplifier DEA) of the digital error amplifier DEA is connected to the output terminal of the first fixed reference voltage unit REF1, the first input terminal (for example, the non-inverting input terminal of the digital error amplifier DEA) of the digital error amplifier DEA is connected to the Drain terminal, the output terminal of the digital error amplifier DEA is connected to one input terminal (for example, the non-inverting input terminal of the operational amplifier OP-amp OP), and the other input terminal (for example, the inverting input terminal of the operational amplifier OP-amp The output end of the switch path of the constant current source M1 and the output end of the operational amplifier OP are used as the output end of the ripple removing module 40, and are connected to the control end of the constant current source M1. Wherein the comparator CMP is used for comparing the trigger voltage VOVPAnd voltage V at Drain terminalDrain(i.e., the voltage across the constant current source M1) and outputs a corresponding comparison result to control the output of the digital error amplifier DEA. The digital error amplifier DEA is arranged to output a comparison result V based on the comparator CMPREF1And VDrainThe signal outputs an analog compensation signal COMP to the operational amplifier OP. The operational amplifier OP is used for controlling the constant current source M1 according to the analog compensation signal COMP and a signal (not shown) output by an output end of a switching path of the constant current source M1, so as to eliminate ripples in the driving current I _ LED, and make the I _ LED a near-direct current.
It should be noted that the digital error amplifier DEA is an error amplifier implemented in the form of a digital circuit, and may specifically include electronic components such as a counter, an oscillator, and a digital-to-analog converter, and the specific circuit design of the digital error amplifier DEA may be any suitable circuit design known in the artDigital circuits, and will not be described in detail herein. In addition, the error amplifier DEA and the comparator CMP may be internally integrated with a voltage V for detecting a Drain terminal, respectivelyDrainThe detection circuit (not shown).
In the ripple removing circuit 4 of this embodiment, the sampling module 41, the reference triggering module 42 and the ripple removing module 40 form a system ripple removing loop, and since the sampling module 41 provides the sampling signal K × I _ LED that dynamically changes along with the driving current I _ LED to the reference triggering module 42, the reference triggering module 42 can provide the triggering voltage V that dynamically changes along with the driving current I _ LED to the comparator CMPOVPThereby enabling the comparator CMP to be dependent on the trigger voltage VOVPDynamically adjusting the comparison result to make the trigger voltage VOVPIs introduced directly into the digital error amplifier DEA, which in turn enables to increase the oscillator frequency of the digital error amplifier DEA and/or to speed up the counting of the counter of the digital error amplifier DEA, i.e. enables the digital error amplifier DEA to be responsive to the trigger voltage VOVPThe change of the analog compensation signal COMP accelerates the change of the analog compensation signal COMP output by the operational amplifier OP, and the accelerated change of the analog compensation signal COMP can accelerate the change of the control signal output by the operational amplifier OP to the control end of the constant current source M1, so that the ripple in the driving current I _ LED is quickly eliminated, the driving current I _ LED can be stabilized quickly, current overshoot is avoided, the system bandwidth is increased, and the system loop response speed is high.
The ripple removing circuit 4 of the present embodiment can dynamically adjust the trigger voltage V for triggering the loop to accelerate based on the magnitude of the load 3 (i.e. based on the magnitude of the driving current I _ LED of the load 3)OVPAnd according to said trigger voltage VOVPControlling the constant current source to quickly remove ripples in the driving current to quickly change the driving current into near-direct current, wherein when the load is small, the driving current I _ LED provided by the driving device 2 is small, and the trigger voltage V isOVPWhen the load is large, the driving current I _ LED provided by the driving device 2 is large, and the trigger voltage V is correspondingly set to be lowOVPIs correspondingly set high, thereby enabling the system to trigger the condition of loop acceleration earlier and improving the condition quickly when the system is started at low current or small angleThe system has the problems of low loop bandwidth, low system loop response speed, easy occurrence of current overshoot and the like in the processes of fast startup and shutdown and small-angle dimming. When load 3 includes the LED lamp, because the current ripple among the filtering drive current I _ LED, consequently can eliminate the stroboscopic problem of LED lamp, in the silicon controlled rectifier is adjusted luminance and is used, can also improve dimming performance, make the system can the quick response silicon controlled rectifier operation of adjusting luminance, and can smooth transition between the different operation of adjusting luminance, the effect after adjusting luminance is stable.
With continued reference to fig. 2 and fig. 4, in the ripple removing circuit 4 of the present embodiment, the constant current source M1, the sampling module 41, the reference triggering module 42, and the ripple removing module 40 may be integrated into a ripple removing chip. Therefore, the present embodiment further provides a ripple removal chip, which includes the ripple removal circuit 4 of the present embodiment.
With reference to fig. 2 and fig. 4, the present embodiment further provides an electronic product, which includes a rectifying circuit 1, a driving device 2, a load 3, a ripple removing circuit 4 and a filtering circuit 5. The rectifier circuit 1 rectifies the AC power AC and outputs the rectified AC power as dc power Vin. The driving device 2 is configured to convert the direct current Vin into a driving current I _ LED with a ripple to drive the load 3 to operate. The ripple removing circuit 4 is disposed on a line through which the driving device 2 delivers the driving current I _ LED to the load 3, and is configured to remove a ripple in the driving current I _ LED. The load 3 and the ripple removing circuit 4 are connected in series to form a series circuit, the filter circuit 5 is connected with the series circuit in parallel, the filter circuit 5 comprises a filter capacitor C1, one end of the filter capacitor C1 is connected with the front end of the load 3, the other end of the filter capacitor C1 is connected with the grounding end of the ripple removing circuit 4, the drive current I _ LED containing low-frequency ripples generates a low-frequency voltage signal on the filter capacitor C1, and the drive current I _ LED is prevented from sudden changing by utilizing the characteristic that the voltage at the two ends of the filter capacitor C1 cannot suddenly change so as to control the ripple amplitude of the drive current I _ LED.
The load 3 may be an LED lamp, or an LED lamp string formed by connecting at least two LED lamps in series and/or in parallel.
The driving device 2 includes a power converter 21, a power switch Q0, a sampling circuit (not shown), and a driving chip 22. The power switch Q0 may be a MOS transistor, and the sampling circuit includes a sampling resistor Rcs connected in series with the switching path of the power switch Q0 (i.e., the source terminal of the power switch Q0) for sampling a voltage signal Vcs on the switching path of the power switch Q0. The power converter 21 is configured to convert a voltage of the direct current output from the rectifier circuit 1 at the previous stage into an operating voltage required by the load 3. The driving chip 22 may be a linear driving chip or an active power factor correction driving chip, the driving chip 22 has a power input pin Vin coupled to the output end of the rectifying circuit 1, a sampling pin CS connected to the source end of the power switch Q0, a ground pin GND, a pin Vcc connected to the drain end of the power switch Q0, and a pin connected to the gate end of the power switch Q0, and the driving chip 22 is configured to control the on/off of the power switch Q0 according to the voltage signal Vcs, so as to control the output of the power converter 21, so as to drive the load 3 to operate. Under the control of the driving chip 22 and the power switching tube Q0, the power converter 21 is configured to convert the direct current Vin into a driving current I _ LED with ripple to drive the load 3 to operate, and the ripple removing circuit 4 is configured to remove the ripple in the driving current I _ LED.
With reference to fig. 16 and fig. 4, the present embodiment further provides an electronic product with a triac dimming function, which includes a triac dimmer 6, a rectifying circuit 1, a driving device 2, a load 3, and a ripple removing circuit 4 according to the present embodiment. The load 3 may be an LED lamp, or may be an LED lamp string formed by connecting at least two LED lamps in series and/or in parallel. One end of the silicon controlled dimmer 6 is connected to the alternating current AC, the other end of the silicon controlled dimmer 6 is connected to the rectifying circuit 1, and the silicon controlled dimmer 6 is used for receiving the alternating current AC and conducting phase cutting processing on the alternating current AC to obtain phase cutting voltage so as to conduct dimming on the load 3. The rectifier circuit 1 is configured to rectify the phase-cut voltage and output the rectified voltage as a dc voltage Vin. The driving device 2 is configured to convert the direct current Vin into a driving current I _ LED with a ripple to drive the load 3 to operate. The ripple removing circuit 4 is disposed on a line through which the driving device 2 delivers the driving current I _ LED to the load 3, and is configured to remove a ripple in the driving current I _ LED.
Example two
Referring to fig. 2 and fig. 5, the present embodiment provides a ripple removing circuit 4 disposed on a line for transmitting a driving current I _ LED to a load 3 by a driving device 2, wherein the ripple removing circuit 4 includes a constant current source M1, a ripple removing module 40, a sampling module 41, and a reference trigger module 42, and the connection manner and specific circuit design of the constant current source M1, the ripple removing module 40, and the sampling module 41, the driving device 2, and the load 3 can be the same as those in the first embodiment, and will not be described in detail herein.
Compared with the ripple removing circuit 4 of the first embodiment, the main difference of the ripple removing circuit 4 of the present embodiment is that the reference trigger module 42 of the present embodiment includes a second adder U3 in addition to the first fixed reference voltage unit REF1, the second fixed reference voltage unit REF2 and the first adder U1. An output terminal of the first fixed reference voltage unit REF1 is connected to an input terminal of a second adder U3, another input terminal of the second adder U3 is connected to the output terminal of the sampling module 41 (i.e., the output terminal of the current sampling unit U2), an output terminal of the second adder U3 is connected to an input terminal of a digital error amplifier DEA (e.g., the inverting input terminal of the digital error amplifier DEA), and the first fixed reference voltage unit REF1 is configured to generate and provide a first fixed reference voltage VREF1The second adder U3 is used for adding the first fixed reference voltage VREF1And the sampling signal K I _ LED is superposed to obtain a dynamic reference voltage V which dynamically changes along with the driving current I _ LEDREF1_EA=VREF1+ K × I _ LED. Thus, the digital error amplifier DEA is based on the dynamic reference voltage V provided by the second adder U3REF1_EAComparison result of comparator CMP output, voltage V of Drain terminalDrainAn analog compensation signal COMP is generated, and an operational amplifier OP can control the constant current source M1 according to the analog compensation signal COMP and the voltage at the output end of the switch path of the constant current source M1 to remove the ripple in the driving current I _ LED.
The ripple removing circuit 4 of this embodiment can also trigger overvoltage protection (based on the size of the load 3) when the system needs to triggerI.e., loop acceleration) condition, the trigger voltage V that triggers the loop bandwidth to change in an accelerated manner is dynamically adjustedOVP Load 3 hours, trigger voltage VOVPWhen the load is 3 big, the trigger voltage V is set lowOVPSet high so that the voltage V at Drain terminalDrainAnd the driving current I _ LED can quickly respond to the trigger voltage VOVPTo improve the problem of slow and possible current overshoot in the system loop setup during fast startup and shutdown and small angle dimming.
But more importantly, due to the ripple removing circuit 4 of the present embodiment, the first fixed reference voltage V is adopted to be fixed compared to the ripple removing circuit 4 of the first embodimentREF1By innovatively proposing the voltage V at the inverting input of the digital error amplifier DEAREF1_EAThe dynamic characteristic of the loop is further improved by the mode of changing along with the size change of the load 3, so that the loop of the circuit system is established faster and the system is stabilized faster in the processes of quick startup and shutdown and small-angle dimming.
In the ripple removing circuit 4 of the present embodiment, the constant current source M1, the sampling module 41, the reference triggering module 42, and the ripple removing module 40 may be integrated into a ripple removing chip. Therefore, with continuing reference to fig. 2 and fig. 5, the present embodiment also provides a ripple removal chip, including the ripple removal circuit 4 of the present embodiment.
With reference to fig. 2 and fig. 5, the present embodiment further provides an electronic product, which includes a rectifying circuit 1, a driving device 2, a load 3, a ripple removing circuit 4 and a filtering circuit 5. The connection mode of the rectifying circuit 1, the driving device 2, the ripple removing circuit 4 and the filter circuit 5 may be the same as that of the electronic product described in the first embodiment, and the specific circuit design of the rectifying circuit 1, the driving device 2 and the filter circuit 5 may also be the same as that of the electronic product described in the first embodiment, which is not described in detail herein.
With reference to fig. 16 and fig. 5, the present embodiment further provides an electronic product with a triac dimming function, which includes a triac dimmer 6, a rectifying circuit 1, a driving device 2, a load 3, and a ripple removing circuit 4 according to the present embodiment. The connection mode of the rectifying circuit 1, the driving device 2, the ripple removing circuit 4 and the filter circuit 5 may be the same as that of the electronic product with the silicon controlled rectifier dimming function described in the first embodiment, and the specific circuit design of the rectifying circuit 1, the driving device 2 and the filter circuit 5 may also be the same as that of the electronic product with the silicon controlled rectifier dimming function described in the first embodiment, which is not described in detail herein.
EXAMPLE III
Referring to fig. 2 and fig. 6, the present embodiment provides a ripple removing circuit 4 disposed on a line for transmitting a driving current I _ LED to a load 3 by a driving device 2, wherein the ripple removing circuit 4 includes a constant current source M1, a ripple removing module 40, a sampling module 41, and a reference trigger module 42, and the connection manner and specific circuit design of the constant current source M1, the reference trigger module 42, and the sampling module 41, the driving device 2, and the load 3 can be the same as those in the first embodiment, and will not be described in detail herein.
The main difference between the ripple removing circuit 4 of the present embodiment and the ripple removing circuit 4 of the first embodiment is that the digital error amplifier DEA in the ripple removing module 40 of the first embodiment is replaced by an analog error amplifier EA. The analog error amplifier EA is an error amplifier implemented in the form of an analog circuit. The output end of the analog error amplifier EA of this embodiment is further connected to a ground capacitance Ccomp, one end of the ground capacitance Ccomp is connected to the output end of the error amplifier EA, and the other end is grounded to GND. The analog error amplifier EA is essentially a transconductance amplifier capable of responding to the trigger voltage VOVPThe change speed of the analog compensation signal COMP is dynamically adjusted. The voltage across the ground capacitor Ccomp has the characteristic of not being suddenly changed, and the trigger voltage V received by the comparator CMPOVPWhen the voltage is increased, the analog compensation signal COMP is changed rapidly, the ground capacitor Ccomp is charged rapidly, and forward current which is much larger than the non-ground capacitor Ccomp can be provided for the operational amplifier OP (namely, pull-up current of the input end of the operational amplifier OP is increased), so that the change of the control signal output by the operational amplifier OP to the constant current source M1 is accelerated, ripples in the driving current are eliminated rapidly, and the ripples are stabilized at a preset value; trigger voltage V received at comparator CMPOVPWhen the voltage is reduced, the analog compensation signal COMP is changed rapidly, and the capacitance to ground Ccomp is fastFast discharge, providing a fast-response trigger voltage V to the operational amplifier OPOVPThe analog compensation signal COMP. In addition, the ground capacitor Ccomp can sensitively feed back the change of the signal at the output end of the analog error amplifier EA, accelerate the response speed of the loop, and prevent the phenomenon of overshoot caused by inputting the comparison result of the comparator CMP to the analog error amplifier EA.
It should be noted that the ground capacitor Ccomp is arranged close to the output end of the error amplifier EA, and grounded by a line as short as possible, so as to avoid the ground capacitor Ccomp occupying too much circuit area and improve the charge-discharge response capability of the ground capacitor Ccomp. The main function of the ground capacitor Ccomp is to filter secondary power frequency ripples and improve the stability of a loop. The capacitance to ground Ccomp may be chosen to be 1 muf, since the larger the capacitance to ground Ccomp, the better the PF value will be, but the weaker the start-up capability will result, the slower the loop setup will be.
In addition, it should be noted that the capacitance to ground Ccomp described in this embodiment is only one implementation, and there may be alternatives and variations. For example, the capacitance to ground Ccomp can be implemented digitally, i.e. by means of an integrator, where the integrator is connected between the output of the analog error amplifier EA and the input of the operational amplifier OP, and the output of the integrator provides the COMP signal to the operational amplifier OP.
Other devices in the ripple removing module 40 of this embodiment are the same as the circuit design and connection manner of the corresponding devices in the ripple removing module 40 described in the first embodiment, and are not described herein again.
The ripple removing circuit 4 of this embodiment can also dynamically adjust the trigger voltage V for triggering the accelerated change of the loop bandwidth when the system needs to trigger the overvoltage protection (i.e. the loop is accelerated) condition based on the size of the load 3OVP3 hours of loading, can trigger the voltage VOVPWhen the load is 3 big, the trigger voltage V can be set lowOVPSet high so that the voltage V at Drain terminalDrainAnd the driving current I _ LED can quickly respond to the trigger voltage VOVPTo improve system loop setup slowness and slowness during fast power on and off and small angle dimmingPotential current overshoot problems.
In the ripple removing circuit 4 of the present embodiment, the constant current source M1, the sampling module 41, the reference trigger module 42, and the analog error amplifier EA, the operational amplifier OP, and the comparator CMP of the ripple removing module 40 may be integrated into a ripple removing chip. Therefore, with continuing reference to fig. 2 and fig. 6, the present embodiment also provides a ripple removal chip, which includes the constant current source M1, the sampling module 41, the reference trigger module 42, and the analog error amplifier EA, the operational amplifier OP, and the comparator CMP of the ripple removal module 40 in the ripple removal circuit 4 of the present embodiment.
With reference to fig. 2 and fig. 6, the present embodiment further provides an electronic product, which includes a rectifying circuit 1, a driving device 2, a load 3, a ripple removing circuit 4 and a filtering circuit 5. The connection mode of the rectifying circuit 1, the driving device 2, the ripple removing circuit 4 and the filter circuit 5 is basically the same as that of the electronic product described in the first embodiment, and the specific circuit design of the rectifying circuit 1, the driving device 2 and the filter circuit 5 may also be the same as that of the electronic product described in the first embodiment, which is not described in detail herein.
With reference to fig. 16 and fig. 6, the present embodiment further provides an electronic product with a triac dimming function, which includes a triac dimmer 6, a rectifying circuit 1, a driving device 2, a load 3, and a ripple removing circuit 4 according to the present embodiment. The connection mode of the rectifying circuit 1, the driving device 2, the ripple removing circuit 4 and the filter circuit 5 may be substantially the same as that of the electronic product with the thyristor dimming function described in the first embodiment, and the specific circuit design of the rectifying circuit 1, the driving device 2 and the filter circuit 5 may also be the same as that of the electronic product with the thyristor dimming function described in the first embodiment, which is not described in detail herein.
Example four
Referring to fig. 7, the present embodiment provides a ripple removing circuit 4 disposed on a line for transmitting a driving current I _ LED to a load 3 by a driving device 2, wherein the ripple removing circuit 4 includes a constant current source M1, a ripple removing module 40, a sampling module 41, and a reference trigger module 42, and the connection manner and specific circuit design of the constant current source M1, the ripple removing module 40, and the sampling module 41, the driving device 2, and the load 3 are the same as those in the third embodiment, and will not be described in detail herein.
Compared with the ripple removing circuit 4 of the third embodiment, the main difference of the ripple removing circuit 4 of the present embodiment is that the reference trigger module 42 of the present embodiment includes a second adder U3 in addition to the first fixed reference voltage unit REF1, the second fixed reference voltage unit REF2 and the first adder U1. An output terminal of the first fixed reference voltage unit REF1 is connected to an input terminal of a second adder U3, another input terminal of the second adder U3 is connected to an output terminal of the sampling module 41 (i.e., an output terminal of the current sampling unit U2), an output terminal of the second adder U3 is connected to an input terminal of the analog error amplifier EA (e.g., an inverting input terminal of the analog error amplifier EA), and the first fixed reference voltage unit REF1 is configured to generate and provide a first fixed reference voltage VREF1The second adder U3 is used for adding the first fixed reference voltage VREF1And the sampling signal K I _ LED is superposed to obtain a dynamic reference voltage V which dynamically changes along with the driving current I _ LEDREF1_EA=VREF1+ K × I _ LED. Thus, the analog error amplifier EA is based on the dynamic reference voltage V provided by the second summer U3REF1_EAComparison result provided by comparator CMP, voltage V at Drain terminalDrainGenerating an analog compensation signal COMP, and controlling the constant current source M1 by an operational amplifier OP according to the analog compensation signal COMP and the voltage at the output end of the switch path of the constant current source M1 to rapidly remove the ripple in the driving current I _ LED.
The ripple removing circuit 4 of this embodiment can also dynamically adjust the trigger voltage V for triggering the accelerated change of the loop bandwidth when the system needs to trigger the overvoltage protection (i.e. the loop is accelerated) condition based on the size of the load 3OVP3 hours of loading, can trigger the voltage VOVPWhen the load is 3 big, the trigger voltage V can be set lowOVPSet high so that the voltage V at Drain terminalDrainAnd the driving current I _ LED can quickly respond to the trigger voltage VOVPTo improve fast on/off and low angle dimmingThe system loop in the process builds up slow and possible current overshoot problems.
But more importantly, due to the ripple removing circuit 4 of the present embodiment, a first fixed reference voltage V that is fixed and unchanged is adopted in the ripple removing circuit 4 compared to the third embodimentREF1By innovatively proposing the voltage V at the inverting input of the digital error amplifier DEAREF1_EAThe dynamic characteristic of the loop is further improved by the mode of changing along with the size change of the load 3, so that the loop of the circuit system is established faster and the system is stabilized faster in the processes of quick startup and shutdown and small-angle dimming.
In the ripple removing circuit 4 of the present embodiment, the constant current source M1, the sampling module 41, the reference trigger module 42, and the analog error amplifier EA, the operational amplifier OP, and the comparator CMP of the ripple removing module 40 may be integrated into a ripple removing chip. Therefore, with continuing reference to fig. 2 and fig. 7, the present embodiment also provides a ripple removal chip, which includes the constant current source M1, the sampling module 41, the reference trigger module 42, and the analog error amplifier EA, the operational amplifier OP, and the comparator CMP of the ripple removal module 40 in the ripple removal circuit 4 of the present embodiment.
With reference to fig. 2 and fig. 7, the present embodiment further provides an electronic product, which includes a rectifying circuit 1, a driving device 2, a load 3, a ripple removing circuit 4 and a filtering circuit 5. The connection mode of the rectifying circuit 1, the driving device 2, the ripple removing circuit 4 and the filter circuit 5 is basically the same as that of the electronic product described in the first embodiment, and the specific circuit design of the rectifying circuit 1, the driving device 2 and the filter circuit 5 may also be the same as that of the electronic product described in the first embodiment, which is not described in detail herein.
With reference to fig. 16 and fig. 7, the present embodiment further provides an electronic product with a triac dimming function, which includes a triac dimmer 6, a rectifying circuit 1, a driving device 2, a load 3, and a ripple removing circuit 4 according to the present embodiment. The connection mode of the rectifying circuit 1, the driving device 2, the ripple removing circuit 4 and the filter circuit 5 may be substantially the same as that of the electronic product with the thyristor dimming function described in the first embodiment, and the specific circuit design of the rectifying circuit 1, the driving device 2 and the filter circuit 5 may also be the same as that of the electronic product with the thyristor dimming function described in the first embodiment, which is not described in detail herein.
EXAMPLE five
Referring to fig. 8, the present embodiment provides a ripple removing circuit 4 disposed on a line of a driving device 2 for supplying a driving current I _ LED to a load 3, wherein the ripple removing circuit 4 includes a constant current source M1, a ripple removing module 40, a sampling module 41, and a reference triggering module 42.
The difference between the ripple removing circuit 4 of this embodiment and the first embodiment is that: (1) the output terminal of the comparator 41 is connected to the third input terminal of the digital error amplifier DEA in the first embodiment, instead, the output terminal of the comparator 41 is coupled to the output terminal of the digital error amplifier DEA and then connected to an input terminal of the operational amplifier OP, so that the time point of loop speed up changes, and the trigger voltage V is setOVPThe change COMP of the analog compensation signal to be received by the operational amplifier OP can be accelerated; (2) the current monitoring unit of the sampling module 41 is replaced by the variable resistor Rp in the first embodiment with a transistor M2 operating in a linear resistance region; (3) the sampling module 41 further includes a sampling control unit kvomp, configured to adjust a resistance value of the transistor M2 operating in the linear resistance region according to the analog compensation signal COMP, specifically, one end of a switch path of the transistor M2 is connected to an output end of a switch path of the constant current source M1, the other end of the switch path of the transistor M2 is connected to one end of the current sampling unit U2, a control end of the transistor M2 is connected to an output end of the sampling control unit kvomp, the other end of the current sampling unit U2 is grounded to GND, and an output end of the current sampling unit U2 is connected to one input end of the first adder U1; the transistor M2 works in the linear resistance area, and the resistance value of the transistor M2 dynamically changes according to the output signal of the sampling control unit KcOMP so as to monitor the driving current I _ LED; the current sampling unit U2 is configured to sample the driving current I _ LED to generate a sampling signal K × I _ LED.
The transistor M2 may be a NOMS transistor or an NPN transistor. When the transistor M2 can be an NOMS transistor, one end of the switch path of the transistor M2 is the drain of the NOMS transistor, the other end of the switch path of the transistor M2 is the source of the NOMS transistor, and the control end of the transistor M2 is the gate of the NOMS transistor; when the transistor M2 may be an NPN transistor, one end of the switch path of the transistor M2 is a collector of the NPN transistor, the other end of the switch path of the transistor M2 is an emitter of the NPN transistor, and the control end of the transistor M2 is a base of the NPN transistor.
The ripple removing circuit 4 of this embodiment is the same as the ripple removing circuit 4 of the first embodiment in terms of other modules and circuit design and connection manner, and will not be described herein again.
The ripple removing circuit 4 of this embodiment can also dynamically adjust the trigger voltage V for triggering the accelerated change of the loop bandwidth when the system needs to trigger the overvoltage protection (i.e. the loop is accelerated) condition based on the size of the load 3OVP3 hours of loading, can trigger the voltage VOVPWhen the load is 3 big, the trigger voltage V can be set lowOVPSet high so that the voltage V at Drain terminalDrainAnd the driving current I _ LED can quickly respond to the trigger voltage VOVPTo improve the problem of slow and possible current overshoot in the system loop setup during fast startup and shutdown and small angle dimming.
In the ripple removing circuit 4 of the present embodiment, the constant current source M1, the sampling module 41, the reference triggering module 42, and the ripple removing module 40 may be integrated into a ripple removing chip. Therefore, with continuing reference to fig. 2 and fig. 8, the present embodiment also provides a ripple removal chip, including the ripple removal circuit 4 of the present embodiment.
With reference to fig. 2 and fig. 8, the present embodiment further provides an electronic product, which includes a rectifying circuit 1, a driving device 2, a load 3, a ripple removing circuit 4 and a filtering circuit 5. The connection mode of the rectifying circuit 1, the driving device 2, the ripple removing circuit 4 and the filter circuit 5 may be the same as that of the electronic product described in the first embodiment, and the specific circuit design of the rectifying circuit 1, the driving device 2 and the filter circuit 5 may also be the same as that of the electronic product described in the first embodiment, which is not described in detail herein.
With reference to fig. 16 and fig. 8, the present embodiment further provides an electronic product with a triac dimming function, which includes a triac dimmer 6, a rectifying circuit 1, a driving device 2, a load 3, and a ripple removing circuit 4 according to the present embodiment. The connection mode of the rectifying circuit 1, the driving device 2, the ripple removing circuit 4 and the filter circuit 5 may be the same as that of the electronic product with the silicon controlled rectifier dimming function described in the first embodiment, and the specific circuit design of the rectifying circuit 1, the driving device 2 and the filter circuit 5 may also be the same as that of the electronic product with the silicon controlled rectifier dimming function described in the first embodiment, which is not described in detail herein.
EXAMPLE six
Referring to fig. 9, the present embodiment provides a ripple removing circuit 4 disposed on a line of a driving device 2 for supplying a driving current I _ LED to a load 3, wherein the ripple removing circuit 4 includes a constant current source M1, a ripple removing module 40, a sampling module 41, and a reference triggering module 42.
The ripple removing circuit 4 of the present embodiment is different from the ripple removing circuit 4 of the fifth embodiment in that the digital error amplifier DEA in the ripple removing module 40 in the fifth embodiment is replaced with an analog error amplifier EA. The analog error amplifier EA is an error amplifier implemented in the form of an analog circuit. The output end of the analog error amplifier EA of this embodiment is further connected to a ground capacitance Ccomp, one end of the ground capacitance Ccomp is connected to the output end of the error amplifier EA, and the other end is grounded to GND. The connection of the analog error amplifier EA and the ground capacitor Ccomp to other circuits can refer to the third embodiment, and will not be described in detail here.
In addition, it should be noted that the capacitance to ground Ccomp described in this embodiment is only one implementation, and there may be alternatives and variations. For example, the capacitance to ground Ccomp can be implemented digitally, i.e. by means of an integrator, where the integrator is connected between the output of the analog error amplifier EA and the input of the operational amplifier OP, and the output of the integrator provides the COMP signal to the operational amplifier OP.
The ripple removing circuit 4 of this embodiment and the ripple removing circuit 4 of the fifth embodiment have the same circuit design and connection manner, and are not described herein again.
The ripple removing circuit 4 of this embodiment can also dynamically adjust the trigger voltage V for triggering the accelerated change of the loop bandwidth when the system needs to trigger the overvoltage protection (i.e. the loop is accelerated) condition based on the size of the load 3OVP3 hours of loading, can trigger the voltage VOVPWhen the load is 3 big, the trigger voltage V can be set lowOVPSet high so that the voltage V at Drain terminalDrainAnd the driving current I _ LED can quickly respond to the trigger voltage VOVPTo improve the problem of slow and possible current overshoot in the system loop setup during fast startup and shutdown and small angle dimming.
In the ripple removing circuit 4 of the present embodiment, the constant current source M1, the sampling module 41, the reference trigger module 42, and the analog error amplifier EA, the operational amplifier OP, and the comparator CMP of the ripple removing module 40 may be integrated into a ripple removing chip. Therefore, with continuing reference to fig. 2 and fig. 9, the present embodiment also provides a ripple removal chip, which includes the constant current source M1, the sampling module 41, the reference trigger module 42, and the analog error amplifier EA, the operational amplifier OP, and the comparator CMP of the ripple removal module 40 in the ripple removal circuit 4 of the present embodiment.
With reference to fig. 2 and fig. 9, the present embodiment further provides an electronic product, which includes a rectifying circuit 1, a driving device 2, a load 3, a ripple removing circuit 4 and a filtering circuit 5. The connection mode of the rectifying circuit 1, the driving device 2, the ripple removing circuit 4 and the filter circuit 5 is basically the same as that of the electronic product described in the first embodiment, and the specific circuit design of the rectifying circuit 1, the driving device 2 and the filter circuit 5 may also be the same as that of the electronic product described in the first embodiment, which is not described in detail herein.
With reference to fig. 16 and fig. 9, the present embodiment further provides an electronic product with a triac dimming function, which includes a triac dimmer 6, a rectifying circuit 1, a driving device 2, a load 3, and a ripple removing circuit 4 according to the present embodiment. The connection mode of the rectifying circuit 1, the driving device 2, the ripple removing circuit 4 and the filter circuit 5 may be substantially the same as that of the electronic product with the thyristor dimming function described in the first embodiment, and the specific circuit design of the rectifying circuit 1, the driving device 2 and the filter circuit 5 may also be the same as that of the electronic product with the thyristor dimming function described in the first embodiment, which is not described in detail herein.
EXAMPLE seven
Referring to fig. 10, the present embodiment provides a ripple removing circuit 4 disposed on a circuit of a driving device 2 for supplying a driving current I _ LED to a load 3. The ripple removing circuit 4 of the present embodiment is different from the ripple removing circuit 4 of the first embodiment in that the digital error amplifier DEA and the comparator CMP are not integrated therein for detecting the voltage V at the Drain terminalDrainThe ripple removing circuit 4 of this embodiment uses the detection module 43 mainly composed of external voltage dividing resistors to detect the voltage V at the Drain endDrain. Specifically, the ripple removal circuit 4 includes a constant current source M1, a ripple removal module 40, a sampling module 41, a reference trigger module 42, and a detection module 43. The specific design and circuit connection of the constant current source M1, the ripple removing module 40, the sampling module 41, and the reference triggering module 42 are the same as those in the first embodiment, and will not be described in detail here. The detection module 43 includes a first voltage-dividing resistor R1 and a second voltage-dividing resistor R2, one end of the first voltage-dividing resistor R1 is connected to the Drain terminal, the other end of the first voltage-dividing resistor R1 is connected to one end of the second voltage-dividing resistor R2, the other end of the second voltage-dividing resistor R2 is grounded to GND, and one end of the first voltage-dividing resistor R1 connected to the second voltage-dividing resistor R2 is used for providing a voltage R1V to the comparator CMP and the error amplifier DEADrain/(R1+R2)。
The ripple removing circuit 4 of this embodiment can also dynamically adjust the trigger voltage V for triggering the accelerated change of the loop bandwidth when the system needs to trigger the overvoltage protection (i.e. the loop is accelerated) condition based on the size of the load 3OVP3 hours of loading, can trigger the voltage VOVPWhen the load is 3 big, the trigger voltage V can be set lowOVPSet high so that the voltage V at Drain terminalDrainAnd the driving current I _ LED can quickly respond to the trigger voltage VOVPTo improve rapiditySlow and possible current overshoot problems are created in the system loop during power-on and power-off and small angle dimming.
In the ripple removing circuit 4 of the present embodiment, the constant current source M1, the sampling module 41, the reference triggering module 42, and the ripple removing module 40 may be integrated into a ripple removing chip. Therefore, with continuing reference to fig. 2 and fig. 10, the present embodiment also provides a ripple removal chip, which includes the constant current source M1, the sampling module 41, the reference trigger module 42, and the ripple removal module 40 of the ripple removal circuit 4 of the present embodiment, and the detection module 43 for detecting the voltage at the Drain end is disposed outside the ripple removal chip and connected to the voltage input end corresponding to the ripple removal chip.
With reference to fig. 2 and fig. 10, the present embodiment further provides an electronic product, which includes a rectifying circuit 1, a driving device 2, a load 3, a ripple removing circuit 4 and a filtering circuit 5. The connection mode of the rectifying circuit 1, the driving device 2, the ripple removing circuit 4 and the filter circuit 5 may be the same as that of the electronic product described in the first embodiment, and the specific circuit design of the rectifying circuit 1, the driving device 2 and the filter circuit 5 may also be the same as that of the electronic product described in the first embodiment, which is not described in detail herein.
With reference to fig. 16 and fig. 10, the present embodiment further provides an electronic product with a triac dimming function, which includes a triac dimmer 6, a rectifying circuit 1, a driving device 2, a load 3, and a ripple removing circuit 4 according to the present embodiment. The connection mode of the rectifying circuit 1, the driving device 2, the ripple removing circuit 4 and the filter circuit 5 may be the same as that of the electronic product with the silicon controlled rectifier dimming function described in the first embodiment, and the specific circuit design of the rectifying circuit 1, the driving device 2 and the filter circuit 5 may also be the same as that of the electronic product with the silicon controlled rectifier dimming function described in the first embodiment, which is not described in detail herein.
Example eight
Referring to fig. 2 and fig. 11, the present embodiment provides a ripple removing circuit 4 disposed on a line for transmitting a driving current I _ LED to a load 3 by a driving device 2, wherein the ripple removing circuit 4 includes a constant current source M1, a ripple removing module 40, a sampling module 41, a reference triggering module 42, and a detection module 43, and the connection manner and specific circuit design of the constant current source M1, the reference triggering module 42, the sampling module 41, and the detection module 43 with the driving device 2 and the load 3 can be the same as those in the seventh embodiment, and will not be described in detail herein.
The ripple removing circuit 4 of the present embodiment is different from the ripple removing circuit 4 of the seventh embodiment in that the digital error amplifier DEA in the ripple removing module 40 of the seventh embodiment is replaced with an analog error amplifier EA. The analog error amplifier EA is an error amplifier implemented in the form of an analog circuit. The output end of the analog error amplifier EA of this embodiment is further connected to a ground capacitance Ccomp, one end of the ground capacitance Ccomp is connected to the output end of the error amplifier EA, and the other end is grounded to GND. The connection of the analog error amplifier EA and the ground capacitor Ccomp to other circuits can refer to the third embodiment, and will not be described in detail here.
In addition, it should be noted that the capacitance to ground Ccomp described in this embodiment is only one implementation, and there may be alternatives and variations. For example, the capacitance to ground Ccomp can be implemented digitally, i.e. by means of an integrator, where the integrator is connected between the output of the analog error amplifier EA and the input of the operational amplifier OP, and the output of the integrator provides the COMP signal to the operational amplifier OP.
The ripple removing circuit 4 of this embodiment and the ripple removing circuit 4 of the seventh embodiment have the same circuit design and connection manner, and are not described herein again.
The ripple removing circuit 4 of this embodiment can also dynamically adjust the trigger voltage V for triggering the accelerated change of the loop bandwidth when the system needs to trigger the overvoltage protection (i.e. the loop is accelerated) condition based on the size of the load 3OVP3 hours of loading, can trigger the voltage VOVPWhen the load is 3 big, the trigger voltage V can be set lowOVPSet high so that the voltage V at Drain terminalDrainAnd the driving current I _ LED can quickly respond to the trigger voltage VOVPTo improve the problem of slow and possible current overshoot in the system loop setup during fast startup and shutdown and small angle dimming.
In the ripple removing circuit 4 of the present embodiment, the constant current source M1, the sampling module 41, the reference trigger module 42, and the analog error amplifier EA, the operational amplifier OP, and the comparator CMP of the ripple removing module 40 may be integrated into a ripple removing chip. Therefore, with continuing reference to fig. 2 and fig. 11, the present embodiment also provides a ripple removal chip, which includes the constant current source M1, the sampling module 41, the reference trigger module 42, and the analog error amplifier EA, the operational amplifier OP, and the comparator CMP of the ripple removal module 40 in the ripple removal circuit 4 of the present embodiment. The capacitance to ground Ccomp and the detection module 43 are disposed outside the ripple removal chip and connected to corresponding pins of the ripple removal chip.
With reference to fig. 2 and fig. 11, the present embodiment further provides an electronic product, which includes a rectifying circuit 1, a driving device 2, a load 3, a ripple removing circuit 4 and a filtering circuit 5. The connection mode of the rectifying circuit 1, the driving device 2, the ripple removing circuit 4 and the filter circuit 5 is basically the same as that of the electronic product described in the first embodiment, and the specific circuit design of the rectifying circuit 1, the driving device 2 and the filter circuit 5 may also be the same as that of the electronic product described in the first embodiment, which is not described in detail herein.
With reference to fig. 16 and fig. 11, the present embodiment further provides an electronic product with a triac dimming function, which includes a triac dimmer 6, a rectifying circuit 1, a driving device 2, a load 3, and a ripple removing circuit 4 according to the present embodiment. The connection mode of the rectifying circuit 1, the driving device 2, the ripple removing circuit 4 and the filter circuit 5 may be substantially the same as that of the electronic product with the thyristor dimming function described in the first embodiment, and the specific circuit design of the rectifying circuit 1, the driving device 2 and the filter circuit 5 may also be the same as that of the electronic product with the thyristor dimming function described in the first embodiment, which is not described in detail herein.
Example nine
Referring to fig. 2 and 12, the present embodiment provides a ripple removing circuit 4 disposed on a line for transmitting a driving current I _ LED to a load 3 by a driving device 2, wherein the ripple removing circuit 4 includes a constant current source M1, a ripple removing module 40, a sampling module 41, a reference triggering module 42, and a detection module 43, and the connection manner and specific circuit design of the constant current source M1, the reference triggering module 42, and the detection module 43, the driving device 2, and the load 3 can be the same as those in the seventh embodiment, and will not be described in detail herein.
The degripping circuit 4 of the present embodiment is different from the degripping circuit 4 of the seventh embodiment in that the variable resistor Rp in the sampling block 41 is replaced with a fixed resistor R0. The voltage on the fixed resistor R0 reflects the condition of the driving current I _ LED, and the current sampling unit U2 can obtain a sampling signal that follows the change of the driving current I _ LED by detecting the change of the voltage on the fixed resistor R0.
The ripple removing circuit 4 of this embodiment can also dynamically adjust the trigger voltage V for triggering the accelerated change of the loop bandwidth when the system needs to trigger the overvoltage protection (i.e. the loop is accelerated) condition based on the size of the load 3OVP3 hours of loading, can trigger the voltage VOVPWhen the load is 3 big, the trigger voltage V can be set lowOVPSet high so that the voltage V at Drain terminalDrainAnd the driving current I _ LED can quickly respond to the trigger voltage VOVPTo improve the problem of slow and possible current overshoot in the system loop setup during fast startup and shutdown and small angle dimming.
In addition, in the ripple removing circuit 4 of this embodiment, the fixed resistor R0 may be internally installed or the fixed resistor R0 may be externally installed according to different application scenarios. When the fixed resistor R0 is built in, in the ripple removing circuit 4 of the present embodiment, the constant current source M1, the sampling module 41, the reference trigger module 42, and the ripple removing module 40 may be integrated into a ripple removing chip. At this time, the present embodiment provides a ripple removing chip, which includes the constant current source M1, the sampling module 41, the reference trigger module 42, and the ripple removing module 40 of the ripple removing circuit 4 of the present embodiment, and is used for detecting the voltage V at the Drain terminalDrainThe detection module 43 may be externally disposed outside the ripple removing chip and connected to the corresponding voltage input terminal of the ripple removing chip. When the fixed resistor R0 is externally disposed, in the ripple removing circuit 4 of the present embodiment, the constant current source M1, the current sampling unit U2 of the sampling module 41, the reference trigger module 42, and the ripple removing module 40 can be integrated into one de-ripple chip. At this time, the present embodiment provides a ripple removing chip, which includes the constant current source M1 of the ripple removing circuit 4 of the present embodiment, the current sampling unit U2 of the sampling module 41, the reference trigger module 42, and the ripple removing module 40, and the detection module 43 for detecting the voltage at the Drain end and the fixed resistor R0 of the sampling module 41 are both disposed outside the ripple removing chip and are respectively connected to corresponding pins of the ripple removing chip.
With reference to fig. 2 and fig. 12, the present embodiment further provides an electronic product, which includes a rectifying circuit 1, a driving device 2, a load 3, a ripple removing circuit 4 and a filtering circuit 5. The connection mode of the rectifying circuit 1, the driving device 2, the ripple removing circuit 4 and the filter circuit 5 may be the same as that of the electronic product described in the first embodiment, and the specific circuit design of the rectifying circuit 1, the driving device 2 and the filter circuit 5 may also be the same as that of the electronic product described in the first embodiment, which is not described in detail herein.
With reference to fig. 16 and fig. 12, the present embodiment further provides an electronic product with a triac dimming function, which includes a triac dimmer 6, a rectifying circuit 1, a driving device 2, a load 3, and a ripple removing circuit 4 according to the present embodiment. The connection mode of the rectifying circuit 1, the driving device 2, the ripple removing circuit 4 and the filter circuit 5 may be the same as that of the electronic product with the silicon controlled rectifier dimming function described in the first embodiment, and the specific circuit design of the rectifying circuit 1, the driving device 2 and the filter circuit 5 may also be the same as that of the electronic product with the silicon controlled rectifier dimming function described in the first embodiment, which is not described in detail herein.
Example ten
Referring to fig. 2 and 13, the present embodiment provides a ripple removing circuit 4 disposed on a line for transmitting a driving current I _ LED to a load 3 by a driving device 2, wherein the ripple removing circuit 4 includes a constant current source M1, a ripple removing module 40, a sampling module 41, a reference triggering module 42, and a detection module 43, and the connection manner and specific circuit design of the constant current source M1, the reference triggering module 42, the sampling module 41, and the detection module 43 with the driving device 2 and the load 3 can be the same as those in the seventh embodiment, and will not be described in detail herein.
The ripple removing circuit 4 of the present embodiment is different from the ripple removing circuit 4 of the seventh embodiment in that the digital error amplifier DEA in the ripple removing module 40 in the ninth embodiment is replaced with an analog error amplifier EA. The analog error amplifier EA is an error amplifier implemented in the form of an analog circuit. The output end of the analog error amplifier EA of this embodiment is further connected to a ground capacitance Ccomp, one end of the ground capacitance Ccomp is connected to the output end of the error amplifier EA, and the other end is grounded to GND. The connection of the analog error amplifier EA and the ground capacitor Ccomp to other circuits can refer to the third embodiment, and will not be described in detail here.
In addition, it should be noted that the capacitance to ground Ccomp described in this embodiment is only one implementation, and there may be alternatives and variations. For example, the capacitance to ground Ccomp can be implemented digitally, i.e. by means of an integrator, where the integrator is connected between the output of the analog error amplifier EA and the input of the operational amplifier OP, and the output of the integrator provides the COMP signal to the operational amplifier OP.
The ripple removing circuit 4 of this embodiment and the ripple removing circuit 4 of the ninth embodiment have the same circuit design and connection manner, and are not described herein again.
The ripple removing circuit 4 of this embodiment can also dynamically adjust the trigger voltage V for triggering the accelerated change of the loop bandwidth when the system needs to trigger the overvoltage protection (i.e. the loop is accelerated) condition based on the size of the load 3OVP3 hours of loading, can trigger the voltage VOVPWhen the load is 3 big, the trigger voltage V can be set lowOVPSet high so that the voltage V at Drain terminalDrainAnd the driving current I _ LED can quickly respond to the trigger voltage VOVPTo improve the problem of slow and possible current overshoot in the system loop setup during fast startup and shutdown and small angle dimming.
In addition, in the ripple removing circuit 4 of this embodiment, the fixed resistor R0 may be internally installed or the fixed resistor R0 may be externally installed according to different application scenarios. When the fixed resistor R0 is built in, the present embodimentIn the ripple circuit 4, the constant current source M1, the sampling module 41, the reference triggering module 42, and the ripple removing module 40 may be integrated into one ripple removing chip. At this time, the present embodiment provides a ripple removing chip, which includes the constant current source M1, the sampling module 41, the reference trigger module 42, and the ripple removing module 40 of the ripple removing circuit 4 of the present embodiment, and is used for detecting the voltage V at the Drain terminalDrainThe detection module 43 is externally arranged outside the ripple removing chip and connected with the corresponding voltage input end of the ripple removing chip. When the fixed resistor R0 is externally disposed, in the ripple removing circuit 4 of the present embodiment, the constant current source M1, the current sampling unit U2 of the sampling module 41, the reference trigger module 42, and the ripple removing module 40 may be integrated into a ripple removing chip. At this time, the present embodiment provides a ripple removing chip, which includes the constant current source M1 of the ripple removing circuit 4 of the present embodiment, the current sampling unit U2 of the sampling module 41, the reference trigger module 42, and the ripple removing module 40, and is used for detecting the voltage V at the Drain terminalDrainThe detection module 43 and the fixed resistor R0 of the sampling module 41 are both disposed outside the ripple removal chip and are respectively connected to corresponding pins of the ripple removal chip.
With reference to fig. 2 and fig. 13, the present embodiment further provides an electronic product, which includes a rectifying circuit 1, a driving device 2, a load 3, a ripple removing circuit 4 and a filtering circuit 5. The connection mode of the rectifying circuit 1, the driving device 2, the ripple removing circuit 4 and the filter circuit 5 may be the same as that of the electronic product described in the first embodiment, and the specific circuit design of the rectifying circuit 1, the driving device 2 and the filter circuit 5 may also be the same as that of the electronic product described in the first embodiment, which is not described in detail herein.
With reference to fig. 16 and fig. 13, the present embodiment further provides an electronic product with a triac dimming function, which includes a triac dimmer 6, a rectifying circuit 1, a driving device 2, a load 3, and a ripple removing circuit 4 according to the present embodiment. The connection mode of the rectifying circuit 1, the driving device 2, the ripple removing circuit 4 and the filter circuit 5 may be the same as that of the electronic product with the silicon controlled rectifier dimming function described in the first embodiment, and the specific circuit design of the rectifying circuit 1, the driving device 2 and the filter circuit 5 may also be the same as that of the electronic product with the silicon controlled rectifier dimming function described in the first embodiment, which is not described in detail herein.
Please refer to fig. 15, in the ripple removing circuit 4 shown in the first to tenth embodiments, the reference triggering module 42 sets V from the phase of fast system startup or small angle dimming to the phase of stable system operationOVP=VREF2+ K X I _ LED, so in the system fast on-off and small angle dimming process, the driving current I _ LED is gradually increased, VOVPWill increase with the increase of I _ LED, after the system is stable, the driving current I _ LED is constant, so VOVPAnd will be constant accordingly. That is, the reference trigger module 42 of the ripple removing circuit 4 shown in the first to tenth embodiments applies the trigger voltage V before and after the system is stabilized (i.e. before and after the driving current is stabilized)OVPThe output is a fixed voltage VREF2And a voltage K x I _ LED proportional to said drive current. However, the technical solution of the present invention is not limited thereto, please refer to fig. 3, and in other embodiments of the present invention, the circuit design of the reference trigger module 42 may be further designed to trigger the voltage V before the driving current I _ LED is stabilizedOVPIs set as VOVP=VREF2+ K X I _ LED to trigger the voltage V after the drive current has stabilizedOVPSet as the peak value V of the voltage at two ends of the constant current sourceDrain_maxThe sum of V0 with another fixed voltage, or a fixed voltage (which may or may not be equal to V)REF2) A voltage K I _ LED proportional to the driving current and a peak value V of the voltage at two ends of the constant current sourceDrain_maxProportional voltage K0VDrain_maxThe sum of (1). See example eleven below for details.
EXAMPLE eleven
Referring to fig. 2 and fig. 14, the present embodiment provides a ripple removing circuit 4 disposed on a line for transmitting a driving current I _ LED to a load 3 by a driving device 2, wherein the ripple removing circuit 4 includes a constant current source M1, a ripple removing module 40, a sampling module 41, and a reference trigger module 42, and connection manners and specific circuit designs of the sampling module 41, the ripple removing module 40, and the reference trigger module 42 with the driving device 2 and the load 3 are the same as those in the first embodiment, and are not described in detail herein.
The difference between the ripple removing circuit 4 of this embodiment and the ripple removing circuit 4 of the first embodiment is that the reference trigger module 42 further includes a trigger voltage adjusting unit 421, one input end of the trigger voltage adjusting unit 421 is connected to the Drain terminal, the other input end of the trigger voltage adjusting unit 421 is connected to the output terminal of the sampling module 41, and the output terminal of the trigger voltage adjusting unit 421 can be connected to the corresponding terminal, such as the enable terminal or the control terminal of the first adder U1. The trigger voltage adjustment unit 421 can collect V in real timeDrainPeak value of (V)Drain_maxOr the sampling signal K × I _ LED collected by the sampling module 41 may be triggered to operate after being unchanged (i.e. the corresponding driving current I _ LED is stable), and start to collect VDrainPeak value of (V)Drain_max. As an example, after the sampling signal K × I _ LED collected by the sampling module 41 is unchanged (i.e. the corresponding driving current I _ LED is stable), the trigger voltage adjustment unit 421 can enable the first adder U1 not to output V any moreOVP=VREF2+ K X I _ LED, but adjusted to output VOVP=V0+VDrain_max. V0 is a fixed voltage, which may be equal to 1V. In addition, V set after system stabilizationOVP=V0+VDrain_maxCan be smaller or larger than the V after the system is stabilizedREF2+ K × I _ LED, V set after system stabilization is shown in fig. 3OVP=V0+VDrain_maxAnd is less than V after the system is stabilizedREF2+ K × I _ LED. Of course, after the sampling signal K × I _ LED collected by the sampling module 41 is unchanged (i.e. the corresponding driving current I _ LED is stable), the trigger voltage adjusting unit 421 can adjust VOVPThe case of (2) is not limited to the above example, but may be any other case that can make VOVPIs not equal to VREF2+ K X I _ LED not equal to VDrainFor example, as another example, after the sampling signal K × I _ LED collected by the sampling module 41 is unchanged (i.e. the corresponding driving current I _ LED is stable), the trigger voltage adjustment unit 421 can also make the first adder U1 not output V any moreOVP=VREF2+ K X I _ LED, but adding the firstThe output of the law machine U1 is adjusted to VOVP=VREF2+K*I_LED+K0*VDrain_maxWherein K0 is a positive or negative number not equal to 0, and when K0 is a positive number not equal to 0, V set after the system is stableOVPGreater than V after system stabilizationREF2+ K I _ LED, when K0 is a negative number not equal to 0, set V after the system is stableOVPLess than V after system stabilizationREF2+ K × I _ LED. As another example, after the sampling signal K × I _ LED collected by the sampling module 41 is unchanged (i.e. the corresponding driving current I _ LED is stable), the trigger voltage adjustment unit 421 can also make the first adder U1 not output V any moreOVP=VREF2+ K × I _ LED, but the output of the first adder U1 is adjusted to VOVP=V01+K*I_LED+K0*VDrain_maxWherein V isOVPIs not equal to VREF2+ K X I _ LED not equal to VDrain,V01Is not equal to VREF2K0 is a positive or negative number not equal to 0, which may be equal to V0 or not equal to V0.
The ripple removing circuit 4 of this embodiment can also dynamically adjust the trigger voltage V for triggering the accelerated change of the loop bandwidth when the system needs to trigger the overvoltage protection (i.e. the loop is accelerated) condition based on the size of the load 3OVP3 hours of loading, can trigger the voltage VOVPWhen the load is 3 big, the trigger voltage V can be set lowOVPSet high so that the voltage V at Drain terminalDrainAnd the driving current I _ LED can quickly respond to the trigger voltage VOVPTo improve the problem of slow and possible current overshoot in the system loop setup during fast startup and shutdown and small angle dimming. More importantly, the de-ripple circuit 4 of the present embodiment can reset a fixed V after the system is stabilized due to the reference trigger module 42OVPTherefore, the overvoltage protection (namely, loop acceleration) condition can not be triggered by mistake in the stable working stage of the system.
It should be noted that, although the load 3 is described as an LED lamp in the above embodiments, the load 3 according to the present invention is not limited to an LED lamp, and may be any other suitable load, such as a dc motor.
It will be apparent to those skilled in the art that various changes and modifications may be made in the invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (17)
1. The utility model provides a remove ripple circuit, its characterized in that, it sets up on a drive arrangement carries the line of drive current to the load to remove ripple circuit, the drive current contains the ripple, it includes to remove ripple circuit:
a constant current source connected in series with the load, the driving current flowing through the constant current source and the load;
the sampling module is used for sampling the driving current to generate a sampling signal which dynamically changes along with the driving current;
the reference trigger module is used for providing at least one fixed reference voltage, generating a corresponding reference voltage and a trigger voltage which dynamically changes along with the driving current according to the sampling signal and the corresponding fixed reference voltage, and dynamically adjusting the corresponding trigger voltage based on the size of a load when a system needs to trigger a loop acceleration condition, wherein the trigger voltage is set to be low when the load is small, and the trigger voltage is set to be high when the load is large; and the number of the first and second groups,
and the ripple removing module is used for controlling the constant current source according to the trigger voltage, the reference voltage and the voltage at two ends of the constant current source so as to remove ripples in the driving current.
2. The ripple removal circuit of claim 1, wherein the trigger voltage output by the reference trigger module is a sum of a fixed voltage and a voltage proportional to the driving current before and after the driving current is stabilized; or the trigger voltage output by the reference trigger module before the driving current is stabilized is the sum of a fixed voltage and a voltage proportional to the driving current, and the trigger voltage output after the driving current is stabilized is the sum of the peak value of the voltage at two ends of the constant current source and another fixed voltage; or, the trigger voltage output by the reference trigger module before the driving current is stabilized is a sum of a fixed voltage and a voltage proportional to the driving current, and the trigger voltage output after the driving current is stabilized is a sum of a fixed voltage, a voltage proportional to the driving current and a voltage proportional to a peak value of a voltage across the constant current source.
3. The de-ripple circuit of claim 2, wherein the reference trigger module comprises:
the first fixed reference voltage unit is used for generating a first fixed reference voltage and providing the first fixed reference voltage as a reference voltage to the ripple removing module;
a second fixed reference voltage unit for providing a second fixed reference voltage; and the number of the first and second groups,
the first adder is used for superposing the second fixed reference voltage and the sampling signal to obtain the trigger voltage;
the ripple removing module is used for controlling the constant current source according to the trigger voltage, the voltage at two ends of the constant current source and the first fixed reference voltage.
4. The de-ripple circuit of claim 2, wherein the reference trigger module comprises:
a first fixed reference voltage unit for providing a first fixed reference voltage;
the second adder is used for superposing the first fixed reference voltage and the sampling signal to obtain a dynamic reference voltage which changes along with the sampling signal;
a second fixed reference voltage unit for providing a second fixed reference voltage;
the first adder is used for superposing the second fixed reference voltage and the sampling signal to obtain the trigger voltage;
the ripple removing module is used for controlling the constant current source according to the trigger voltage, the voltage at two ends of the constant current source and the dynamic reference voltage.
5. The ripple removing circuit according to claim 3 or 4, wherein the reference trigger module further comprises a trigger voltage adjusting unit for acquiring a peak value of the voltage across the constant current source, and adjusting the trigger voltage output by the first adder to a sum of the peak value of the voltage across the constant current source and another fixed voltage or to a sum of a fixed voltage, a voltage proportional to the drive current, and a voltage proportional to the peak value of the voltage across the constant current source after the drive current acquired by the sampling module is stabilized.
6. The de-ripple circuit of claim 1, wherein the de-ripple module comprises:
the comparator is used for comparing the trigger voltage with the voltage at two ends of the constant current source and outputting a corresponding trigger signal according to the comparison result;
the error amplifier is used for outputting an analog compensation signal according to the difference between the voltage at the two ends of the constant current source and the reference voltage provided by the reference triggering module;
the operational amplifier is used for controlling the constant current source according to the received analog compensation signal so as to remove ripples in the driving current;
the error amplifier also receives the trigger signal output by the comparator and accelerates the change of the output analog compensation signal according to the trigger signal; or, the output end of the comparator and the output end of the error amplifier are coupled and then connected to the input end of the operational amplifier, so as to accelerate the change of the analog compensation signal to be received by the operational amplifier according to the trigger signal.
7. The degripping circuit according to claim 6, wherein the error amplifier is a digital error amplifier implemented in the form of a digital circuit or an analog error amplifier implemented in the form of an analog circuit.
8. The de-ripple circuit of claim 7, wherein when the error amplifier is an analog error amplifier, the de-ripple module further comprises a capacitance to ground or an integrator; one end of the ground capacitor is connected with the output end of the error amplifier, and the other end of the ground capacitor is grounded; the integrator is connected between the output of the error amplifier and the input of the operational amplifier.
9. The ripple removing circuit according to claim 6, wherein detection circuits for detecting voltages across the constant current sources are respectively integrated inside the error amplifier and the comparator; or, the ripple removing circuit further includes a detection module disposed outside the sampling module and the ripple removing module and configured to detect a voltage across the constant current source, where the detection module includes a first voltage-dividing resistor and a second voltage-dividing resistor, one end of the first voltage-dividing resistor is connected to a node where the constant current source is connected to the load, the other end of the first voltage-dividing resistor is connected to one end of the second voltage-dividing resistor, the other end of the second voltage-dividing resistor is grounded, and one end of the first voltage-dividing resistor connected to the second voltage-dividing resistor is at least configured to provide a corresponding voltage signal to the comparator and the error amplifier.
10. The ripple removing circuit according to claim 6, wherein the sampling module includes a current monitoring unit and a current sampling unit, and the load, the constant current source, the current monitoring unit and the current sampling unit are connected in sequence to form a series circuit; the current monitoring unit is used for monitoring the driving current flowing through the series circuit; the current sampling unit is used for sampling the driving current monitored by the current monitoring unit so as to output the sampling signal to the reference triggering module.
11. The degripping circuit according to claim 10, wherein the current monitoring unit includes a variable resistor or a fixed resistor or a transistor operating in a linear resistance region.
12. The degripping circuit according to claim 11, wherein when the current monitoring unit includes a variable resistor or a transistor operating in a linear resistance region, the sampling module further includes a sampling control unit for adjusting a resistance value of the variable resistor or the transistor operating in the linear resistance region according to the analog compensation signal.
13. The ripple removing circuit of claim 10, wherein the current sampling unit comprises a multiplier, and the multiplier is configured to multiply the driving current monitored by the current monitoring unit by K to output the sampling signal to the reference trigger module, wherein K is a positive number different from 0 and 1.
14. The degripper circuit of claim 6, wherein the constant current source includes at least one constant current switch having a control terminal, an input terminal of a switch path, and an output terminal of the switch path; the input end of a switch path of the constant current switch is at least connected with one end of the load and the ripple removing module, the output end of the switch path of the constant current switch is connected with the input end of the sampling module or grounded, and the control end of the constant current switch is connected with the output end of the ripple removing module.
15. The de-ripple circuit of claim 6, wherein at least the constant current source, the reference trigger module, and the de-ripple module are integrated in a same chip.
16. A ripple removal chip, comprising the ripple removal circuit according to any one of claims 1 to 15.
17. An electronic product, comprising:
the rectifying circuit is used for rectifying the accessed alternating current and outputting the alternating current as direct current;
a load;
the driving device is used for converting the direct current into driving current with ripples so as to drive the load to work; and the number of the first and second groups,
the ripple removing circuit according to any one of claims 1 to 15, wherein the ripple removing circuit is disposed on a line on which the driving device delivers the driving current to the load, and is configured to remove a ripple in the driving current.
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