CN109379811B - LED drive circuit with output current self-adjusting capability - Google Patents
LED drive circuit with output current self-adjusting capability Download PDFInfo
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Abstract
The invention discloses an LED driving circuit with output current self-adjusting capability, which comprises a single-phase alternating current input power supply, a rectifier bridge, a first power switch tube, a second power switch tube, a first power diode, a second power diode, a first inductor, a first capacitor, a second capacitor, a high-frequency transformer, a first current sampling resistor, a second current sampling resistor, a first voltage sampling resistor, a second voltage sampling resistor, a third voltage sampling resistor, a fourth voltage sampling resistor, an absorption capacitor, an absorption diode and an active power factor correction module. The invention provides a solution for solving the problem that an LED works in an over-rated current state for a long time due to the fact that a parallel branch is broken. The LED lighting circuit has the characteristics of stability and high safety, and is suitable for controlling various LED lighting circuits.
Description
Technical Field
The invention belongs to the field of LED driving, and relates to an LED driving circuit which can cope with LED damage and has output current self-regulation capability.
Technical Field
With the rapid development of the power industry and power electronic technology, the gradual exhaustion of traditional fossil energy and the continuous deterioration of climate environment, energy conservation and environmental protection have become the focus of global attention. With the rapid development of semiconductor technology, LEDs have come into the sight of people as emerging light sources. The LED has the characteristics of small volume, low heat productivity, low power consumption, long service life, high reaction speed and the like. When the LEDs are in large-scale and different colors, the LED driving power supply is a guarantee for the development of an LED industrial chain, and the quality of the LED driving power supply directly influences the reliability of LED products.
The current-voltage characteristic curve of the LED similar to an exponential type determines that the LED is preferably controlled by constant current. However, if the LED driving is in the constant current control mode, when a certain LED fails and is turned off, the LED in the series branch cannot operate, and the current flowing through the LED in the parallel branch increases, which may cause damage for a long time. The measure widely adopted at present is to increase the number of the parallel branches of the LED, and when the open circuit fault occurs to the LED of a certain path, the current is shared by the rest branches, so that the influence is reduced. However, this method still cannot avoid the LED operating at a state higher than the rated current for a long time, and as the number of open branches increases, the operating state of the rest LEDs will gradually deteriorate.
Disclosure of Invention
In view of this, the present invention provides an LED driving circuit with output current self-adjusting capability, which is an LED driving scheme for solving the problem of long-term increase of the current of the remaining parallel branches due to LED open circuit. The LED driving circuit is in constant current output in the initial stage, and the output current of the LED driving circuit is given by the reference of the initial output current, so that N LED loads work in the optimal state; in the constant-current operation process, the LED driving power circuit detects whether the LED load has an open circuit fault by observing whether the fluctuation of the load end voltage reaches a certain threshold value; when the occurrence of an open circuit fault is detected, the driving power supply enters a constant voltage output mode, and the output voltage of the driving power supply is controlled to be the optimal working voltage of the N LEDs; and after the current is stabilized, detecting the output current in a stable state as a new constant current reference value, and switching to a constant current output mode. According to the scheme, when the LED of a certain branch circuit is broken, the output current of the LED in a constant current driving mode can be automatically adjusted, and the LED can work in a good power supply environment.
The invention solves the technical problems in the prior art and is realized by the following technical scheme: an LED driving circuit with output current self-adjusting capability comprises a single-phase alternating current input power supply, a single-phase rectifier bridge, a first power switch tube, a second power switch tube, a first power diode, a second power diode, a first inductor, a first capacitor, a second capacitor, a high-frequency transformer, a first current sampling resistor, a second current sampling resistor, a first voltage sampling resistor, a second voltage sampling resistor, a third voltage sampling resistor, a fourth voltage sampling resistor, an absorption capacitor, an absorption diode, an active power factor correction control module, a constant current control module, a constant voltage control module, a detection control module, a primary reference point, a secondary reference point and N LEDs, wherein N is a positive integer; the high-frequency transformer comprises a primary winding, a secondary winding and an auxiliary winding; the constant voltage control module comprises a voltage sampling port, a grounding port and an output port; the constant current control module comprises a current sampling port, a grounding port and an output port; the active power factor correction control module comprises an output current sampling port, an input voltage sampling port, an output voltage sampling port, an input voltage sampling common end, a grounding port and a gate signal output port); the detection control module comprises a current sampling port, a voltage sampling port, a constant voltage signal input port, a constant current signal input port, a grounding port and a gate pole output port;
one input end of the single-phase alternating-current input power supply is connected with one alternating-current input end of the single-phase rectifier bridge and the voltage sampling port of the active power factor correction control module; the other input end of the single-phase alternating current input power supply is connected with the other alternating current input end of the single-phase rectifier bridge and the voltage sampling common end of the active power factor correction control module; the direct current side positive output end of the single-phase rectifier bridge is connected with the first inductor; the direct-current side negative output end of the single-phase rectifier bridge is connected with one end of the first current sampling resistor; the other end of the first current sampling resistor is connected with the first power switching tube and the primary side reference point; the other end of the first inductor is connected with the drain electrode of the first power switch tube and the anode of the first power diode; the cathode of the first power diode is connected with the positive end of the first capacitor, one end of the first voltage sampling resistor, one end of the absorption capacitor and the non-dotted end of the primary winding of the high-frequency transformer; the negative end of the first capacitor is connected with the primary side reference point; the other end of the first voltage sampling resistor is connected with one end of the second voltage sampling resistor and an output voltage sampling port of the active power factor correction control module; the other end of the second sampling resistor is connected with the primary side voltage reference point; the dotted terminal of the primary winding of the high-frequency transformer is connected with the anode of the absorption diode and the drain of the second power switch tube; the cathode of the absorption diode is connected with the other end of the absorption resistor and the other end of the absorption resistor; the ground port of the active power factor correction control module is connected with the primary side reference point; a gate signal output port of the active power factor correction control module is connected with a gate of the first power switching tube;
the non-homonymous end of the secondary winding of the high-frequency transformer is connected with a secondary reference point; the dotted terminal of the secondary winding of the high-frequency transformer is connected with the anode of the second power diode; the cathode of the second power diode is connected with the anode of the second capacitor and the anodes of the N LEDs; the negative electrode of the second capacitor is connected with the N negative electrodes and the secondary reference point;
the source electrode of the second power switch tube is connected with the current detection port of the constant current control module, the current detection port of the detection control module and one end of the second current sampling resistor; the other end of the second current sampling resistor is connected with the primary side reference point; the non-homonymous end of the auxiliary winding of the high-frequency transformer is connected with a primary reference point; the dotted end of the auxiliary winding of the high-frequency transformer is connected with one end of the third voltage sampling resistor; the other end of the third voltage sampling resistor is connected with one end of the fourth sampling resistor, a voltage detection port of the constant voltage control module and a voltage detection port of the detection control module; the other end of the fourth voltage sampling resistor is connected with the primary side reference point; the ground port of the detection control module is connected with the primary side reference point; the ground port of the constant voltage control module is connected with the primary side reference point; the ground port of the constant current control module is connected with the primary side reference point; and a gate signal output port of the detection control module is connected with a gate of the second power switching tube.
Furthermore, the single-phase alternating-current input power supply and the single-phase rectifier bridge form an uncontrolled rectifier circuit; the first inductor, the first power switch tube, the first power diode and the first capacitor form a boost circuit; the second power switch tube, the high-frequency transformer, the second power diode, the second capacitor, the absorption resistor, the absorption capacitor and the absorption diode form a flyback circuit.
Further, the operation mode of the boost circuit comprises a DCM mode; the working mode of the flyback circuit comprises a DCM mode.
Further, the control method adopted by the active power factor correction control module is average current control; the control method adopted by the constant current control module is PID control based on current feedback; the control method adopted by the constant voltage control module is PID control based on voltage feedback.
Furthermore, the first power diode and the second power diode are power schottky diodes; the absorption diode is a standard recovery diode.
Further, the first capacitor is an energy storage electrolytic capacitor; the second capacitor and the absorption capacitor are high-frequency capacitors.
Furthermore, the high-frequency transformer is a flyback high-frequency transformer, the dotted ends of the primary winding, the secondary winding and the auxiliary winding are opposite, and shielding layers are arranged among the primary winding, the auxiliary winding and the secondary winding.
Furthermore, the first power switch tube and the second power switch tube are both power MOSFET tubes; the first power switch tube and the second power switch tube work independently; the first power switch tube is controlled by the active power factor correction control module; the second power switch tube is controlled by the output of the detection control module.
Further, the output voltage Uo of the secondary winding of the high-frequency transformer supplies power for the N LED loads.
Further, the single-phase rectifier bridge is a rectifier bridge module or a rectifier bridge constructed by four discrete diodes.
Furthermore, the arrangement mode of the N LEDs is a mode of firstly connecting in series and then connecting in parallel; each parallel branch is connected with r LEDs in series, r is greater than or equal to 1, m parallel branches are provided in total, m is greater than or equal to 2, and m multiplied by r is equal to N; when r equals 1, the N LEDs are in parallel.
Further, the LED driving circuit is in constant current output in the initial stage, the output current of the LED driving circuit is given by the reference of the initial output current, and the N LED loads work in the optimal state; in the constant-current operation process, the LED driving power circuit detects whether the LED load has an open circuit fault by observing whether the fluctuation of the load end voltage reaches a certain threshold value; when the occurrence of an open circuit fault is detected, the driving power supply enters a constant voltage output mode, and the output voltage of the driving power supply is controlled to be the optimal working voltage of the N LEDs; and after the current is stabilized, detecting the output current in a stable state as a new constant current reference value, and switching to a constant current output mode.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention corrects the power factor of the AC network side, realizes high PF and low THD, and avoids harmonic pollution of LED lighting equipment to the power grid.
2. The invention adopts constant current control when the LED has no open circuit fault, and caters to the similar exponential volt-ampere characteristic of the LED so as to obtain the optimal lighting effect.
3. The LEDs of the invention adopt a connection structure of first series connection and then parallel connection (or parallel connection), and when the open circuit fault occurs to a certain path of LEDs, the LEDs of the other parallel branches can still continue to work.
4. The invention can detect the open circuit fault of the LED in time, change the output current in time and avoid the influence on the service life of the LED caused by the excessive current of other LEDs for a long time.
Drawings
Fig. 1 is a schematic diagram of an LED driving circuit with output current self-adjusting capability according to the present invention.
Fig. 2 is a control flow chart of an LED driving circuit with output current self-adjusting capability according to the present invention.
Fig. 3 is a block diagram of active power factor correction control based on average current control.
Fig. 4 is a voltage current output simulation curve for active power factor correction based on average current control.
Fig. 5 is a voltage current input simulation curve for active power factor correction based on average current control.
Fig. 6 is a power factor simulation curve for active power factor correction based on average current control.
Fig. 7 is an input current FFT analysis of active power factor correction based on average current control.
Fig. 8 is a block diagram of voltage feedback based flyback converter PID control.
Fig. 9 is a block diagram of a current feedback based flyback converter PID control.
FIG. 10 is a flow diagram of a detection control module implementation.
Fig. 11 is a simulation curve of the output voltage of the driving circuit when an LED open-circuit fault occurs.
Fig. 12 is a simulation curve of the output current of the driving circuit when an LED open-circuit fault occurs.
Fig. 13 shows a change in the output switching amount of the detection control module when an LED open-circuit fault occurs.
Fig. 14 is a graph comparing output current waveforms with and without current self-regulation capability in the event of an LED open circuit fault.
Detailed Description
The following description will further explain embodiments of the present invention by referring to the figures and the specific embodiments. It should be noted that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and all other embodiments obtained by those skilled in the art without any inventive work based on the embodiments of the present invention belong to the protection scope of the present invention
As shown in fig. 1, the present embodiment provides an LED driving circuit with output current self-adjusting capability, which includes a single-phase ac input power source Uin, a single-phase rectifier bridge DB1, a first power switch S1, a second power switch S2, a first power diode D1, a second power diode D2, a first inductor L1, a first capacitor C1, a second capacitor C2, a high-frequency transformer T, a first current sampling resistor Rcs, a second current sampling resistor Rc, a first voltage sampling resistor Rvs1, the LED driving circuit comprises a second voltage sampling resistor Rvs2, a third voltage sampling resistor Rv1, a fourth voltage sampling resistor Rv2, an absorption resistor Rsn, an absorption capacitor Csn, an absorption diode Dsn, an active power factor correction control module Con1, a constant current control module Con2, a constant voltage control module Con3, a detection control module Con4, a primary reference point GND1, a secondary reference point GND2 and N LEDs, wherein N is a positive integer; the high-frequency transformer T comprises a primary winding N1, a secondary winding N2 and an auxiliary winding Naux; the constant voltage control module Con3 comprises a voltage sampling port VS, a ground port GND and an output port OP; the constant current control module Con2 comprises a current sampling port CS, a ground port GND and an output port OP; the active power factor correction control module Con1 comprises an output current sampling port CS, an input voltage sampling port VC, an output voltage sampling port VS, an input voltage sampling common terminal Com, a ground port GND and a GATE signal output port GATE; the detection control module Con4 comprises a current sampling port CS, a voltage sampling port VS, a constant voltage signal input port CV, a constant current signal input port CC, a ground port GND and a GATE electrode output port GATE;
an input end of the single-phase alternating-current input power source Uin is connected with an alternating-current input end of the single-phase rectifier bridge DB1 and the voltage sampling port VC of the active power factor correction control module Con 1; the other input end of the single-phase alternating-current input power Uin is connected with the other alternating-current input end of the single-phase rectifier bridge DB1 and the voltage sampling common end Com of the active power factor correction control module Con 1; the positive output end of the direct current side of the single-phase rectifier bridge DB1 is connected with the first inductor L1; the negative output end of the direct current side of the single-phase rectifier bridge DB1 is connected with one end of the first current sampling resistor Rcs; the other end of the first current sampling resistor Rcs is connected with the first power switch tube S1 and the primary reference point GND 1; the other end of the first inductor L1 is connected to the drain of the first power switch tube S1 and the anode of the first power diode D1; a cathode of the first power diode D1 is connected to a positive terminal of the first capacitor C1, one end of the first voltage sampling resistor Rvs1, one end of the absorption resistor Rsn, one end of the absorption capacitor Csn, and a non-dotted terminal of a primary winding N1 of the high-frequency transformer T; the negative end of the first capacitor C1 is connected with the primary reference point GND 1; the other end of the first voltage sampling resistor Rvs1 is connected with one end of the second voltage sampling resistor and an output voltage sampling port VS of the active power factor correction control module Con 1; the other end of the second sampling resistor is connected with the primary side voltage reference point GND 1; the dotted terminal of a primary winding N1 of the high-frequency transformer T is connected with the anode of the absorption diode Dsn and the drain of the second power switch tube S2; the cathode of the absorption diode Dsn is connected with the other end of the absorption resistor Rsn and the other end of the absorption resistor Rsn; the ground port GND of the active power factor correction control module Con1 is connected to the primary reference point GDN 1; a GATE signal output port GATE of the active power factor correction control module Con1 is connected with a GATE of the first power switching tube;
the non-dotted terminal of a secondary winding N2 of the high-frequency transformer T is connected with a secondary reference point GND 2; the dotted terminal of a secondary winding N2 of the high-frequency transformer T is connected with the anode of the second power diode D2; the cathode of the second power diode D2 is connected with the anode of the second capacitor C2 and the anodes of the N LEDs; the cathode of the second capacitor C2 is connected with the cathodes of the N LEDs and the secondary reference point GND 2;
a source of the second power switch tube S2 is connected to the current detection port CS of the constant current control module Con2, the current detection port CS of the detection control module Con4, and one end of the second current sampling resistor Rc; the other end of the second current sampling resistor Rc is connected with the primary reference point GND 1; the non-dotted terminal of the auxiliary winding Naux of the high-frequency transformer T is connected with a primary reference point GND 1; the dotted end of the auxiliary winding Naux of the high-frequency transformer T is connected with one end of the third voltage sampling resistor Rv 1; the other end of the third voltage sampling resistor Rv1 is connected to one end of the fourth sampling resistor, the voltage detection port VS of the constant voltage control module Con3, and the voltage detection port VS of the detection control module Con 4; the other end of the fourth voltage sampling resistor is connected with the primary side reference point GND 1; the ground port GND of the detection control module Con4 is connected to the primary reference point GND 1; the ground port GND of the constant voltage control module Con3 is connected with the primary reference point GND 1; the ground port GND of the constant current control module Con2 is connected with the primary reference point GND 1; the GATE signal output port GATE of the detection control module Con4 is connected to the GATE of the second power switch tube.
In the embodiment, the single-phase alternating-current input power source Uin and the single-phase rectifier bridge DB1 form an uncontrolled rectifier circuit; the first inductor L1, the first power switch tube S1, the first power diode D1 and the first capacitor C1 form a boost circuit; the second power switch tube S2, the second power diode D2 of the high frequency transformer (T), the second capacitor C2, the absorption resistor Rsn, the absorption capacitor Csn, and the absorption diode Dsn form a flyback circuit.
In this embodiment, the operation mode of the boost circuit includes a DCM mode; the working mode of the flyback circuit comprises a DCM mode.
In this embodiment, the control method adopted by the active power factor correction control module Con1 is average current control; the control method adopted by the constant current control module Con2 is PID control based on current feedback; the control method adopted by the constant voltage control module Con3 is PID control based on voltage feedback.
In the present embodiment, the first power diode D1 and the second power diode D2 are power schottky diodes; the absorption diode Dsn is a standard recovery diode.
In this embodiment, the first capacitor C1 is an energy storage electrolytic capacitor; the second capacitor C2 and the absorption capacitor Csn are high-frequency capacitors.
In this embodiment, the high-frequency transformer T is a flyback high-frequency transformer, the dotted ends of the primary winding N1, the secondary winding N2, and the auxiliary winding Naux are opposite, and a shielding layer is disposed between the primary winding N1, the auxiliary winding Naux, and the secondary winding N2.
In this embodiment, the first power switch tube S1 and the second power switch tube S2 are both power MOSFET tubes; the first power switch tube S1 and the second power switch tube S2 work independently; the first power switch tube S1 is controlled by the active power factor correction control module Con 1; the second power switch S2 is controlled by the output of the detection control module Con 4.
In the present embodiment, the output voltage Uo of the secondary winding N2 of the high-frequency transformer T supplies power to N LED loads.
In the present embodiment, the single-phase rectifier bridge DB1 is a rectifier bridge module or a rectifier bridge constructed by four discrete diodes.
In this embodiment, the arrangement of the N LEDs is first in series and then in parallel; each parallel branch is connected with r LEDs in series, r is greater than or equal to 1, m parallel branches are provided in total, m is greater than or equal to 2, and m multiplied by r is equal to N; when r equals 1, the N LEDs are in parallel.
As shown in fig. 2, the working principle of this embodiment is as follows: the LED driving power supply circuit with the current self-adjusting capability is in constant current output in an initial stage, and the output current of the LED driving power supply circuit is given by the reference of the initial output current, so that N LED loads work in the optimal state; in the constant-current operation process, an LED driving power circuit detects the voltage fluctuation of a load end, when the voltage fluctuation reaches a certain threshold value, a driving power enters a constant voltage output mode, and the output voltage is the optimal working voltage of N LEDs; and after the current is stabilized, detecting the output current in a stable state as a new constant current reference value, and switching to a constant current output mode.
As shown in fig. 3, in the present embodiment, the active power factor correction control module (Con1) adopts boost circuit active power factor correction control based on average current; the outer ring is an output voltage ring, and the inner ring is a rectifier bridge output current ring. Wherein U isinFor an input voltage on the AC side, UrefFor outputting a voltage reference value, U, to an active power factor correction circuitoutFor the output voltage of the active power factor correction circuit, ILFor the inductive current of the active power factor correction circuit, G is the gate control signal of the switching tube of the active power factor correction circuit, PI1Is a first PI controller, PI2 is a second PI controller, IwFor current waveform reference,. DELTA.U.S. output voltage error, IprefFor current amplitude reference, IrefTo output current reference, Δ I is the output current error. Input voltage U at AC sideinObtaining a current waveform reference I through an absolute value arithmetic unit and an amplifierw(ii) a Reference value U of output voltagerefMinus the output voltage UoutObtaining an output voltage error delta U; the output voltage error is processed by a first PI controller PI1 to obtain a current amplitude reference Ipref(ii) a Current amplitude reference IprefAnd current waveform reference IwMultiplying to obtain an output current reference value Iref(ii) a Output current reference value IrefSubtracting the output current value ILObtaining an output current error delta I; and the output current error delta I passes through a second PI controller PI2 and an amplitude limiter and then is compared with sawtooth waves to obtain a flyback circuit switching tube gate control signal G. Through double-loop control, the phase of the input current can accurately track the phase of the input voltage, and the purpose of power factor compensation is achieved.
As shown in fig. 4, the active power factor correction control output voltage adopted in the present embodiment has the characteristics of small ripple and high response speed; as shown in fig. 5, the input voltage and the input current can be well phase-synchronized; as shown in fig. 6 and 7, by the active power factor compensation of the present embodiment, the power factor of the LED driving power circuit with current self-adjusting capability of the present invention can reach over 0.98, and the current distortion rate is 7.5%, i.e. it has the characteristics of high PF and low THD.
As shown in fig. 8, in the present embodiment, the constant voltage control module Con3 adopts PID control based on voltage feedback, so that the voltage can quickly track the voltage reference value; wherein U isrefFor flyback circuit output voltage reference value, UoutThe output voltage of the flyback circuit is delta U, the voltage error is delta U, G2 is a switch tube gate control signal of the flyback circuit, and PI3 is a third PI controller; flyback circuit output voltage reference value UrefSubtracting the output voltage U of the flyback circuitoutObtaining a voltage error delta U, and comparing the voltage error delta U with the sawtooth wave after passing through a third PI controller PI3 and an amplitude limiter to obtain a flyback circuit switchGate control signal G2 is gated off.
As shown in fig. 9, in the present embodiment, the constant current control module Con2 adopts PID control based on current feedback, so that the current can quickly track the voltage reference value; wherein IrefFor flyback circuit output current reference value, IoutFor the output current of the flyback circuit, G1 is a switch gate control signal of the flyback circuit, and PI4 is a fourth PI controller; flyback circuit output current reference value IrefSubtracting the output current I of the flyback circuitoutAnd obtaining a current error delta I, and comparing the voltage error delta I with a sawtooth wave after passing through a fourth PI4 and an amplitude limiter to obtain a flyback circuit switch tube gate control signal G1.
In the present embodiment, the detection control module Con4 is used for detecting the output voltage and current, controlling the output mode of the driving circuit, and updating the current reference value of the constant current control module Con 2; the detection control module is internally provided with a switching value S, when the switching value S is equal to 0, the detection control module Con4 adjusts the output mode to be a constant current output mode, and when the switching value S is equal to 1, the detection control module Con4 adjusts the output mode to be a constant voltage output mode; when S is equal to 0, if the fluctuation of the output voltage is detected to exceed a threshold value, triggering the switching value to jump, and entering a constant voltage mode; when entering a constant voltage mode, a timer built in a detection control module Con4 enables output current to be periodically detected, when the fluctuation of the current is lower than a threshold value, the sampling of the output current value is triggered, the sampling value is used as a reference value of a new constant current module Con2, and then switching value jumping is carried out; the specific implementation principle is as shown in fig. 10, and the detection control module Con4 is matched with the constant current control module Con2 and the constant voltage control module Con3, so that the output current of the driving circuit of the present invention can be automatically adjusted.
As shown in fig. 11 and 12, the drive circuit outputs a voltage/current value simulation waveform, and an LED open fault occurs at 0.5s in this simulation. The driving power supply is driven to quickly respond at the moment of 0.5s, the working mode is immediately adjusted to be the constant-voltage working mode when the output voltage is detected to exceed the threshold value, the driving power supply switches the working mode to be the constant-current working mode in the vicinity of 0.83s through a series of operations such as time delay, output current sampling, loading of current reference values and the like, and the output current at the moment is adjusted. As can be clearly seen from the variation of the switching value S shown in fig. 13, the LED driving power circuit with the current self-adjusting capability of the present invention operates.
Fig. 14 is a comparison of output current simulation waveforms of the LED driving power supply without current self-adjusting capability and the LED driving power supply with current self-adjusting capability according to the present invention when an LED open circuit fault occurs, where the output current 2 is an output current simulation curve of the LED driving power supply with current self-adjusting capability according to the present invention, and the output current 1 is an output current simulation curve of the LED driving power supply without current self-adjusting capability. Therefore, the LED driving power supply with the current self-adjusting capability can quickly react and adjust the current when the LED has an open circuit fault, so that the LED is prevented from working in an overlarge current state for a long time.
In summary, the LED driving circuit with self-adjusting output current according to the present invention deals with the LED driving scheme that the current of the other parallel branches increases for a long time due to the LED open circuit. According to the scheme, when the LED of a certain branch circuit is broken, the output current of the LED in a constant current driving mode can be automatically adjusted, and the LED can work in a good power supply environment.
Claims (10)
1. An LED drive circuit with output current self-adjusting capability, characterized in that: the constant-current power supply comprises a single-phase alternating-current input power supply (Uin), a single-phase rectifier bridge (DB 1), a first power switch tube (S1), a second power switch tube (S2), a first power diode (D1), a second power diode (D2), a first inductor (L1), a first capacitor (C1), a second capacitor (C2), a high-frequency transformer (T), a first current sampling resistor (Rcs), a second current sampling resistor (Rc), a first voltage sampling resistor (Rvs 1), a second voltage sampling resistor (Rvs 2), a third voltage sampling resistor (Rv 1), a fourth voltage sampling resistor (Rv 2), an absorption resistor (Rsn), an absorption capacitor (Csn), an absorption diode (Dsn), an active power factor correction control module (Con1), a constant-current control module (Con2), a constant-voltage control module (Con3), a detection control module (Cs 4), a primary side (Cs 1), a secondary side (N2) and GND reference points, n is a positive integer; the high-frequency transformer (T) comprises a primary winding (N1), a secondary winding (N2) and an auxiliary winding (Naux); the constant voltage control module (Con3) comprises a voltage sampling port (VS), a ground port (GND) and an Output Port (OP); the constant current control module (Con2) comprises a current sampling port (CS), a ground port (GND) and an Output Port (OP); the active power factor correction control module (Con1) comprises an output current sampling port (CS), an input voltage sampling port (VC), an output voltage sampling port (VS), an input voltage sampling common terminal (Com), a ground port (GND) and a GATE signal output port (GATE); the detection control module (Con 4) comprises a current sampling port (CS), a voltage sampling port (VS), a constant voltage signal input port (CV), a constant current signal input port (CC), a ground port (GND) and a GATE output port (GATE);
an input of the single-phase alternating current input power source (Uin) is connected with an alternating current input of the single-phase rectifier bridge (DB 1) and the input voltage sampling port (VC) of the active power factor correction control module (Con 1); the other input end of the single-phase alternating-current input power supply (Uin) is connected with the other alternating-current input end of the single-phase rectifier bridge (DB 1) and the voltage sampling common end (Com) of the active power factor correction control module (Con 1); the positive output end of the direct current side of the single-phase rectifier bridge (DB 1) is connected with the first inductor (L1); the negative output end of the direct current side of the single-phase rectifier bridge (DB 1) is connected with one end of the first current sampling resistor (Rcs) and the output current sampling port (CS) of the active power factor correction control module (Con 1); the other end of the first current sampling resistor (Rcs) is connected with the source electrode of the first power switch tube (S1) and the primary side reference point (GND 1); the other end of the first inductor (L1) is connected with the drain electrode of the first power switch tube (S1) and the anode of the first power diode (D1); the cathode of the first power diode (D1) is connected with the positive terminal of the first capacitor (C1), one end of the first voltage sampling resistor (Rvs 1), one end of the absorption resistor (Rsn), one end of the absorption capacitor (Csn) and the non-dotted terminal of the primary winding (N1) of the high-frequency transformer (T); the negative end of the first capacitor (C1) is connected with the primary reference point (GND 1); the other end of the first voltage sampling resistor (Rvs 1) is connected with one end of the second voltage sampling resistor and an output voltage sampling port (VS) of the active power factor correction control module (Con 1); the other end of the second voltage sampling resistor is connected with the primary side reference point (GND 1); the dotted terminal of a primary winding (N1) of the high-frequency transformer (T) is connected with the anode of the absorption diode (Dsn) and the drain of the second power switch tube (S2); the cathode of the absorption diode (Dsn) is connected with the other end of the absorption resistor (Rsn) and the other end of the absorption capacitor (Csn); the ground port (GND) of the active power factor correction control module (Con1) is connected with the primary reference point (GND 1); a GATE signal output port (GATE) of the active power factor correction control module (Con1) is connected with a GATE of the first power switching tube;
the non-homonymous terminal of a secondary winding (N2) of the high-frequency transformer (T) is connected with a secondary reference point (GND 2); the dotted terminal of a secondary winding (N2) of the high-frequency transformer (T) is connected with the anode of the second power diode (D2); the cathode of the second power diode (D2) is connected with the anode of the second capacitor (C2) and the anodes of the N LEDs; the cathode of the second capacitor (C2) is connected with the cathodes of the N LEDs and the secondary reference point (GND 2);
the source of the second power switch tube (S2) is connected with the current detection port (CS) of the constant current control module (Con2), the current detection port (CS) of the detection control module (Con 4) and one end of the second current sampling resistor (Rc); the other end of the second current sampling resistor (Rc) is connected with the primary side reference point (GND 1); the non-dotted terminal of the auxiliary winding (Naux) of the high-frequency transformer (T) is connected with a primary reference point (GND 1); the dotted terminal of the auxiliary winding (Naux) of the high-frequency transformer (T) is connected with one terminal of the third voltage sampling resistor (Rv 1); the other end of the third voltage sampling resistor (Rv 1) is connected to one end of the fourth voltage sampling resistor, the voltage detection port (VS) of the constant voltage control module (Con3), and the voltage detection port (VS) of the detection control module (Con 4); the other end of the fourth voltage sampling resistor is connected with the primary side reference point (GND 1); the ground port (GND) of the detection control module (Con 4) is connected with the primary reference point (GND 1); the ground port (GND) of the constant voltage control module (Con3) is connected with the primary reference point (GND 1); the ground port (GND) of the constant current control module (Con2) is connected with the primary side reference point (GND 1); a GATE signal output port (GATE) of the detection control module (Con 4) is connected with a GATE of the second power switch tube; the constant-voltage signal input port (CV) of the detection control module (Con 4) is connected with the Output Port (OP) of the constant-voltage control module (Con3), and the constant-current signal input port (CC) of the detection control module (Con 4) is connected with the Output Port (OP) of the constant-current control module (Con 2).
2. The LED driving circuit with self-regulation of output current as claimed in claim 1, wherein: the single-phase alternating current input power supply (Uin) and the single-phase rectifier bridge (DB 1) form an uncontrolled rectifier circuit; the first inductor (L1), the first power switch tube (S1), the first power diode (D1) and the first capacitor (C1) form a boost circuit; the flyback circuit comprises the second power switch tube (S2), the high-frequency transformer (T), the second power diode (D2), the second capacitor (C2), the absorption resistor (Rsn), the absorption capacitor (Csn) and the absorption diode (Dsn).
3. The LED driving circuit with self-regulation of output current as claimed in claim 2, wherein: the working mode of the boost circuit comprises a current interruption mode; the working mode of the flyback circuit comprises a current discontinuous mode.
4. The LED driving circuit with self-regulation of output current as claimed in claim 1, wherein: the control method adopted by the active power factor correction control module (Con1) is average current control; the constant current control module (Con2) adopts a control method of PID control based on current feedback; the control method adopted by the constant voltage control module (Con3) is PID control based on voltage feedback.
5. The LED driving circuit with self-regulation of output current as claimed in claim 1, wherein: the first power diode (D1) and the second power diode (D2) are power Schottky diodes; the absorption diode (Dsn) is a standard recovery diode.
6. The LED driving circuit with self-regulation of output current as claimed in claim 1, wherein: the first capacitor (C1) is an energy storage electrolytic capacitor; the second capacitor (C2) and the absorption capacitor (Csn) are high-frequency capacitors.
7. The LED driving circuit with self-regulation of output current as claimed in claim 1, wherein: the high-frequency transformer (T) is a flyback high-frequency transformer, the dotted ends of the primary winding (N1), the secondary winding (N2) and the auxiliary winding (Naux) are opposite, and shielding layers are arranged among the primary winding (N1), the auxiliary winding (Naux) and the secondary winding (N2).
8. The LED driving circuit with self-regulation of output current as claimed in claim 1, wherein: the first power switch tube (S1) and the second power switch tube (S2) are both power MOSFET tubes; the first power switch tube (S1) and the second power switch tube (S2) work independently; the first power switch (S1) is controlled by the active power factor correction control module (Con 1); the second power switch (S2) is controlled by the output of the detection control module (Con 4).
9. The LED driving circuit with self-regulation of output current as claimed in claim 1, wherein: the secondary winding output voltage Uo of the high-frequency transformer (T) supplies power for the N LED loads; the single-phase rectifier bridge (DB 1) is a rectifier bridge module or a rectifier bridge built by four discrete diodes.
10. The LED driving circuit with self-regulation of output current as claimed in claim 1, wherein: the arrangement mode of the N LEDs is a mode of firstly connecting in series and then connecting in parallel; each parallel branch is connected with r LEDs in series, r is greater than or equal to 1, m parallel branches are provided in total, m is greater than or equal to 2, and m multiplied by r is equal to N; when r equals 1, the N LEDs are in parallel.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102014559A (en) * | 2010-11-19 | 2011-04-13 | 宁波龙源照明电器有限公司 | Light-emitting diode light source driving power supply |
| CN102105009A (en) * | 2011-03-25 | 2011-06-22 | 上海新进半导体制造有限公司 | High power factor light-emitting diode (LED) driving power supply and control circuit thereof |
| CN102215618A (en) * | 2010-04-09 | 2011-10-12 | 复旦大学 | LED (light emitting diode) street lamp driving circuit capable of regulating output illuminance automatically |
| CN102917503A (en) * | 2012-10-25 | 2013-02-06 | 常州矽能电子科技有限公司 | LED driver system with energy storage function |
| CN104540271A (en) * | 2014-12-16 | 2015-04-22 | 广州怡泰照明电子科技有限公司 | Self-adaptive type LED driving circuit |
| CN108135048A (en) * | 2017-12-12 | 2018-06-08 | 深圳市崧盛电子股份有限公司 | A kind of power limitation control driving circuit and driving power |
| CN108513407A (en) * | 2018-05-04 | 2018-09-07 | 深圳市必易微电子有限公司 | A kind of low-frequency ripple suppression circuit and control method |
| CN108601146A (en) * | 2018-05-11 | 2018-09-28 | 福州大学 | A kind of high-power factor and output ripple and low Flyback/Sepic LED drive circuits |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102244964B (en) * | 2011-07-07 | 2013-09-25 | 矽力杰半导体技术(杭州)有限公司 | Hybrid multi-output power supply and regulating method thereof |
-
2018
- 2018-11-20 CN CN201811386811.4A patent/CN109379811B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102215618A (en) * | 2010-04-09 | 2011-10-12 | 复旦大学 | LED (light emitting diode) street lamp driving circuit capable of regulating output illuminance automatically |
| CN102014559A (en) * | 2010-11-19 | 2011-04-13 | 宁波龙源照明电器有限公司 | Light-emitting diode light source driving power supply |
| CN102105009A (en) * | 2011-03-25 | 2011-06-22 | 上海新进半导体制造有限公司 | High power factor light-emitting diode (LED) driving power supply and control circuit thereof |
| CN102917503A (en) * | 2012-10-25 | 2013-02-06 | 常州矽能电子科技有限公司 | LED driver system with energy storage function |
| CN104540271A (en) * | 2014-12-16 | 2015-04-22 | 广州怡泰照明电子科技有限公司 | Self-adaptive type LED driving circuit |
| CN108135048A (en) * | 2017-12-12 | 2018-06-08 | 深圳市崧盛电子股份有限公司 | A kind of power limitation control driving circuit and driving power |
| CN108513407A (en) * | 2018-05-04 | 2018-09-07 | 深圳市必易微电子有限公司 | A kind of low-frequency ripple suppression circuit and control method |
| CN108601146A (en) * | 2018-05-11 | 2018-09-28 | 福州大学 | A kind of high-power factor and output ripple and low Flyback/Sepic LED drive circuits |
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