CN110784953A - Stroboflash-free light emitting diode driving device and linear voltage stabilizing method - Google Patents
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Abstract
The invention discloses a stroboflash-free light-emitting diode driving device and a linear voltage stabilizing method, and relates to the technical field of light-emitting diode drivers; the power conversion circuit comprises an alternating current-direct current converter, and converts alternating current power to generate input voltage; a transformer having a primary coil and a secondary coil isolated from each other and electromagnetically coupled to each other, the primary coil being electrically connected to the AC-DC converter; a changeover switch electrically connected to the primary coil; the controller is electrically connected with the change-over switch and is used for modulating the working period of the change-over switch; and an output stage rectifier electrically connected to the secondary coil and providing output voltage with ripple to the LED string; the feedback circuit is electrically connected with the output stage rectifier and generates a feedback signal according to the state of the light-emitting diode lamp string to be used as a basis for the controller to modulate the change-over switch; the invention is convenient for realizing the phenomenon of avoiding screen flash by quickly adjusting the node voltage, and meanwhile, the invention has simple and convenient control and can improve the efficiency.
Description
The technical field is as follows:
the invention belongs to the technical field of light-emitting diode drivers, and particularly relates to a non-stroboscopic light-emitting diode driving device and a linear voltage stabilizing method.
Background art:
although leds continue to improve in cost and reliability, making them more suitable for use in indoor and outdoor lighting applications, it remains a challenge to provide drivers suitable for the drive currents of led light strings. It is well known that variations in the drive current supplied to the led string will affect its performance.
In particular, light emitting diodes receiving drive current from a power supply that obtains a single phase ac input from a primary or similar power supply are susceptible to the presence of residual voltage ripple resulting from incomplete suppression of waveforms emitted by ac components of the rectifier circuit disposed at or near the input of the power supply, as well as ac components in the form of sinusoidal voltages having twice the frequency of the ac voltage of the primary or similar power supply.
Light emitting diodes are diodes and have a low differential impedance (differential impedance is defined as the ratio of Voltage (VLED) to current (ILED) change) over their operating region. The low differential impedance results in a significant generation of ripple current in the form of voltage ripple in the led, as shown in fig. 1.
Because the voltage difference between the two ends of the led string must be greater than the junction voltage value to be able to emit light, if the instantaneous voltage of the pulsating dc power supply outputted by the driver is less than the junction voltage value, the led string will be extinguished, which leads to the phenomenon of stroboflash (Flicker) of the led lamp, taking the pulsating dc power supply with a frequency of 120Hz as an example, the stroboflash frequency is also 120 Hz.
Although human eyes are not easy to feel the flicker phenomenon for the light source with the frequency of 120hz, for the image capturing device with the periodic scanning sensing, the image captured under the light source with the frequency of 120hz will cause the stroboscopic phenomenon due to the frequency difference between the scanning frequency and the light source, so that a plurality of parallel stripes are formed on the image, and the image is distorted.
The invention content is as follows:
the problem that images shot by the existing light emitting diode under a light source with the frequency of 120Hz are distorted due to a stroboscopic phenomenon caused by the frequency difference between the scanning frequency and the light source frequency, and a plurality of parallel stripes are formed on the images is solved; the invention provides a non-stroboscopic light-emitting diode driving device and a linear voltage stabilizing method.
The invention relates to a non-stroboscopic light-emitting diode driving device, which comprises a power supply conversion circuit, a feedback circuit and a linear voltage stabilizing circuit, wherein the power supply conversion circuit is connected with the feedback circuit;
the power conversion circuit comprises an alternating current-to-direct current converter which converts alternating current power to generate input voltage; a transformer having a primary coil and a secondary coil isolated from each other and electromagnetically coupled to each other, the primary coil being electrically connected to the AC-DC converter; a changeover switch electrically connected to the primary coil; the controller is electrically connected with the change-over switch and is used for modulating the working period of the change-over switch; and an output stage rectifier electrically connected to the secondary coil and providing output voltage with ripple to the LED string;
the feedback circuit is electrically connected with the output stage rectifier and generates a feedback signal according to the state of the light-emitting diode lamp string to serve as a basis for the controller to modulate the change-over switch;
the linear voltage stabilizing circuit is electrically connected with the output stage rectifier, the feedback circuit and the light emitting diode lamp string, and adjusts the output voltage according to the voltage difference between the output voltage and the cross voltage of the light emitting diode lamp string.
Preferably, the linear voltage stabilizing circuit comprises a transistor, a capacitor, a first resistor, a second resistor and a sampling unit; the first resistor is bridged between the capacitor and the current output end of the transistor; a second resistor electrically connected to the capacitor and the feedback circuit; the current source is electrically connected to the light-emitting diode lamp string; the sampling unit is electrically connected with the light-emitting diode lamp string and the current source and is used for sampling the voltage passing through the light-emitting diode lamp string to generate a sampling signal; and the operational amplifier compares the sampling signal with the reference voltage and provides a signal to reduce the on-resistance value of the transistor to change the feedback signal when the sampling signal is smaller than the reference voltage.
Preferably, the operational amplifier provides another signal to maintain the on-resistance of the transistor when the sampling signal is equal to the reference voltage.
Preferably, the feedback circuit comprises an optical coupler, a current-limiting resistor, a voltage stabilizer, a first voltage-stabilizing resistor and a second voltage-stabilizing resistor; the optical coupler comprises a light emitting piece and a light receiving piece, and the light emitting piece and the light receiving piece are used as the basis for providing the feedback signal according to the brightness of the light emitting piece; the current limiting resistor is bridged between the output-stage rectifier and the light-emitting element; the voltage stabilizer is electrically connected between the light-emitting piece and the grounding end; a first voltage stabilizing resistor connected across the output stage rectifier and a control terminal of the voltage stabilizer; and the second voltage stabilizing resistor is connected with the first voltage stabilizing resistor in series, wherein when the sampling signal is less than the reference voltage, the brightness of the luminous element is increased to change the feedback signal so as to lead the working period of the lifting switch of the switch to be increased.
Preferably, the power conversion circuit further includes a vibration damping unit electrically connected to the ac-dc converter, the primary coil, and the changeover switch, the vibration damping unit suppressing a voltage stress on the changeover switch by absorbing a voltage surge derived from a leakage inductance of the transformer.
Preferably, the vibration damping unit includes a diode, a resistor, and a capacitor; the diode is electrically connected to the AC-DC converter; the resistor is connected in series with the diode; and the capacitor is connected in parallel with the resistor.
Preferably, the power conversion circuit further comprises an electromagnetic interference filter, an input stage capacitor and an output stage capacitor; the electromagnetic interference filter is electrically connected with the alternating current-direct current converter to filter electromagnetic noise in alternating current power; the input stage capacitor is electrically connected between the alternating current-direct current converter and the primary coil; and the output stage capacitor is electrically connected between the output stage rectifier and the feedback circuit.
A linear voltage stabilizing method for a non-stroboscopic light-emitting diode driving device comprises providing an output voltage with a ripple to a load; providing a feedback signal when a low valley voltage passing through the load is less than a reference voltage; and linearly adjusting the level of the output voltage according to the feedback signal.
A linear voltage stabilizing method for a non-stroboscopic light-emitting diode driving device further comprises the step of providing a feedback signal to maintain the level of an output voltage when the valley voltage after passing through a load is equal to the reference voltage.
A linear voltage stabilizing method for a non-stroboscopic light-emitting diode driving device is characterized in that the linear voltage stabilizing circuit also receives alternating current power and converts the alternating current power into the output voltage.
Compared with the prior art, the invention has the beneficial effects that: the phenomenon that screen flash happens is avoided by conveniently and quickly adjusting the node voltage, and meanwhile, the control is simple and convenient, and the efficiency can be improved.
Description of the drawings:
for ease of illustration, the invention is described in detail by the following detailed description and the accompanying drawings.
FIG. 1 is a waveform diagram of driving voltage and driving current generated by a conventional LED driver;
FIG. 2 is a block diagram of the circuit of the present invention;
FIG. 3 is a voltage waveform diagram of a node A under different states according to the present invention.
Fig. 4 is a voltage waveform diagram of the node two B in different states according to the present invention.
Fig. 5 is a voltage waveform diagram of node three C in different states according to the present invention.
Fig. 6 is a voltage waveform diagram of the node four D in different states according to the present invention.
Fig. 7 is a voltage waveform diagram of node five E in different states according to the present invention.
Fig. 8 is a voltage waveform diagram of node six F in different states according to the present invention.
1-a power conversion circuit; 10-ac-dc converter; 12-an input stage capacitor; 14-a transformer; 140-a primary coil; 142-a secondary coil; 16-an output stage rectifier; 18-an output stage capacitor; 20-a diverter switch; 22-a controller; 26-a vibration damping unit; 28-a current sense resistor; 3-a feedback circuit; 30-a first voltage-dividing resistor; 32-a second voltage dividing resistor; 34-a current limiting resistor; 36-a voltage regulator; 38-an optical coupler; 380-a light emitting member; 382-light receiving; 5-a linear voltage stabilizing circuit; 50-a current source; 52-an operational amplifier; 54-a sampling unit; 56-a transistor; 58-a first resistor; 60-a second resistor; 62-a capacitor; 7-a light emitting diode string; 70-a light emitting diode; A. b, C, D, E, F-node one, node two, node three, node four, node five, and node six; AC _ In-AC power supply; vin-input voltage; vout-output voltage; vref-reference voltage.
The specific implementation mode is as follows:
in order that the objects, aspects and advantages of the invention will become more apparent, the invention will be described by way of example only, and in connection with the accompanying drawings. It is to be understood that such description is merely illustrative and not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.
It should be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and/or processing steps closely related to the scheme according to the present invention are shown in the drawings, and other details not so relevant to the present invention are omitted.
As shown in fig. 2, the following technical solutions are adopted in the present embodiment: the LED lamp string comprises a power supply conversion circuit 1, a feedback circuit 3 and a linear voltage stabilizing circuit 5, and is used for supplying power to an LED lamp string 7; the led string 7 includes a plurality of leds 70 connected in series.
The power conversion circuit 1 includes an ac-dc rectifier 10, an input stage capacitor 12, a transformer 14, an output stage rectifier 16, an output stage capacitor 18, a switch 20, a controller 22, and a power adjustment unit 24.
The AC-dc rectifier 10 is electrically connected to an AC power supply AC _ In, and the input stage capacitor 12 is electrically connected between the AC-dc rectifier 10 and the transformer 14; the AC-dc rectifying unit 10 cooperates with the input stage capacitor 12 to convert AC power provided by the AC power source AC _ In into a dc input voltage Vin. The alternating current power supply AC _ In can be commercial power alternating current; the AC-dc rectifier 10 may be, for example, a bridge rectifier In a full bridge rectifier, and is configured to convert AC power provided by an AC power source AC _ In into full-wave rectified power. The input stage capacitor 12 provides filtering to smooth the full wave rectified power generated by the ac-to-dc rectifier 10.
The transformer 14 includes a primary coil 140 and a secondary coil 142, which are isolated from each other and may be electromagnetically coupled to each other. The primary coil 140 is located at one side (i.e., input stage) of the power conversion circuit 1 connected to the AC power AC _ In and receives the input voltage Vin, and the secondary coil 142 is located at one side (i.e., output stage) of the power conversion circuit 1 connected to the led string 7; the power conversion circuit 1 transmits the input voltage Vin of the input stage to the output stage through the primary coil 140 and the secondary coil 142.
The output stage rectifier 16 is electrically connected to the secondary winding 142 for rectifying the voltage transmitted to the output stage to generate a (dc) output voltage Vout; as shown in fig. 2, the output stage rectifier 16 may be implemented as a diode. An output stage capacitor 18 is electrically connected to the output stage rectifier 16 to provide filtering to smooth the output voltage Vout.
The switch 20 is electrically connected to the primary coil 140, is not connected to the ac-dc converter 10 and the input stage capacitor 12 to receive the input voltage Vin, and is modulated by a control signal provided by the controller 22. In the exemplary embodiment shown in fig. 2, the switch 20 is depicted as an n-pass Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET).
The power conversion circuit 1 may further include a snubber unit 26 that suppresses voltage stress on the switch 20 by absorbing a voltage surge originating from a leakage inductance of the transformer 14. More specifically, the damping unit 26 includes a diode 260, a resistor 262 and a capacitor 264; the drain of the switch 20 is connected back to the ac-dc rectifier 10 through a diode 260 and a resistor 262 to prevent the switch 20 from having excessive voltage and to provide a current circulation path when the switch 20 is not conducting, and a capacitor 264 is connected in parallel with the resistor 262. The source of the switch 20 is electrically connected to the ground GND1 through the current sense resistor 28, and the voltage across the current sense resistor 28 is provided as a sense voltage to the controller 22.
The power conversion circuit 1 may further include an electromagnetic interference filter 29 electrically connected between the AC power AC _ In and the AC-to-dc rectifier 10 for filtering electromagnetic noise In the AC power outputted from the AC power AC _ In.
The feedback circuit 3 is used for obtaining a feedback signal related to the status of the led string 7, and the controller 22 can modulate the duty cycle of the switch 20 according to the feedback signal. In fig. 2, the feedback circuit 3 includes a first voltage dividing resistor 30, a second voltage dividing resistor 32, a current limiting resistor 34, a voltage regulator 36 and an optical coupler 38. One end of the first voltage-dividing resistor 30 is electrically connected to the cathode of the diode implementing the output stage rectifier 16 and the led string 7, and one end of the second voltage-dividing resistor 32 is electrically connected to the other end of the first voltage-dividing resistor 30; the other end of the second voltage divider resistor 32 is connected to the ground GND 2. Current limiting resistor 34 is electrically connected at one end to the cathode of the diode implementing output stage rectifier 16 and at the other end to node six F. The voltage regulator 36 is connected across a light emitting element 380 of the optocoupler 38 and the ground GND2, and a control terminal of the voltage regulator 36 is connected to a node five E between the first voltage divider resistor 30 and the second voltage divider resistor 32, and performs a voltage stabilizing operation in response to a voltage at the node five E. Light-emitting element 380 may be a light-emitting diode having an anode electrically connected to node six F and a cathode electrically connected to voltage regulator 36.
The light emitting element 380 in the optocoupler 38 cooperates with the operation of the voltage regulator 36 to generate a feedback signal related to the load status of the led string 7 on the light receiving element 382 according to the output voltage Vout to the controller 22, so that the controller 22 controls the switch 20 according to the feedback signal. In the exemplary embodiment shown in fig. 2, the light receiving element 382 is shown as a phototransistor.
The linear regulator circuit 5 is electrically connected to the power conversion circuit 1, the feedback circuit 3, and the led string 7, and can linearly regulate the voltage entering the led string 7 (i.e., the voltage at the node one a) according to the voltage across the led string 7 (i.e., the voltage at the node two B).
In FIG. 2, the linear voltage regulation circuit 5 includes a current source 50, an operational amplifier 52, a sampling unit 54, a transistor 56, a first resistor 58, a second resistor 60, and a capacitor 62. The current source 50 is connected across the negative terminal of the led string 7 (which is connected to the second node B) and the ground terminal GND2, and the inverting input terminal (-; which is connected to the third node C) of the operational amplifier 54 is electrically connected to the second node B where the current source 50 is connected to the led string 7 through the sampling unit 54; the non-inverting input (+) of the operational amplifier 54 is electrically connected to a reference voltage Vref, and the output terminal (connected to node four D) is electrically connected to the control terminal (i.e., base) of the transistor 56. The current input terminal (i.e., the collector) of transistor 56 is electrically coupled to node five E through first resistor 60, and the current output terminal (i.e., the emitter) of transistor 56 is electrically coupled to ground GND 2. The second resistor 60 is connected in series with the capacitor 62, and one end of the capacitor 62 not connected to the second resistor 60 is electrically connected to the node five E, and one end of the second resistor 60 not connected to the capacitor is electrically connected to a cathode of the light emitting diode implementing the light emitting member 380.
Generally, when the led driving apparatus is in normal operation, the controller 22 generates a corresponding control signal to modulate the operation of the power conversion circuit 1 in response to the power requirement of the led string 7. Under this condition, when the switch 20 is turned on in response to the (pulse width modulation) control signal generated by the controller 22, the input voltage Vin is connected across the primary winding 140 of the transformer 14, so that the inductive current of the primary winding 140 of the transformer 14 is linearly increased to store energy. At the same time, at the output stage, the secondary winding 142 of the transformer 14 passes no current due to reverse bias blocking by the diodes implementing the output stage rectifier 16.
On the other hand, when the switch 20 is turned off (turned off) in response to the (pulse width modulation) signal generated by the controller 22, the energy stored in the primary winding 140 of the transformer 14 is transferred to the secondary winding 142 of the transformer 14 based on Lenz's law. At the same time, the energy transferred to the secondary winding 142 of the transformer 14 charges the output stage capacitor 18 and supplies the output voltage Vout, since the diode of the output stage rectifier 16 is made forward biased conductive.
Since the output voltage Vout provided by the power conversion circuit 1 is a ripple voltage, the voltage at the node a is also a ripple voltage, as shown in fig. 3. Secondly, because the voltage difference between the two ends of the led string 7 must be greater than the junction voltage value to be able to emit light, if the instantaneous voltage of the voltage at the node a is less than the junction voltage value of the led string, the led string 7 will be extinguished, and further a stroboscopic phenomenon will occur. Therefore, stabilizing the voltage at node a is a method that can effectively prevent the led string 7 from stroboscopic.
In this embodiment, the first voltage divider resistor 30, the second voltage divider resistor 32 and the first resistor 58 divide the output voltage Vout to generate a voltage to the led string 7 at a node a; wherein when the voltage of the node A is V
AThe first voltage divider resistor 30 has a resistance value of R
upThe second voltage divider 32 has a resistance value of R
dn1The resistance value of the first resistor 58 is R
dn2When, satisfy the following formula condition:
as can be seen from FIG. 4, the voltage at node two B (denoted by V in FIG. 4)
B) Has a waveform similar to the voltage of node one A (i.e., V in FIG. 3)
A) The waveform of (a); the difference between the two is that they have different voltage levels. In detail, when the voltage of the node A is V
AThe voltage of the node two B is V
BThe on-state voltage of the LED lamp string 7 is V
LEDThen, the following conditions are satisfied:
V
A-V
LED＝V
B；
as mentioned above, when the voltage of the first node a decreases, the voltage of the second node B decreases accordingly; therefore, the voltage of the first node A can be obtained by monitoring the voltage of the second node B. The linear voltage regulating circuit 5 utilizes the voltage of the monitoring node two B as the basis for adjusting the voltage of the node one a.
The sampling unit 54 samples the valley voltage of the node two B and transmits the sampling result to the inverting input (-) of the operational amplifier 52; the line VC shown in FIG. 4 is the valley voltage of node two B.
The operational amplifier 52 compares the valley voltage of the node two B obtained by the sampling result with the reference voltage Vref, and outputs a high level signal to increase the voltage of the node four D (VD shown in fig. 5) when the valley voltage of the node two B is smaller than the reference voltage Vref, so as to decrease the voltage of the node five E (VE shown in fig. 5). When the voltage at node five E decreases, the voltage at node six F, VF in FIG. 5, increases; when the voltage at node six F increases, the brightness of the light-emitting element 380 is changed to cause the controller 22 to modulate the duty cycle of the switch 22, so as to gradually increase the voltage at node one a.
When the voltage of the first node a is gradually increased, the voltage of the second node B and the voltage of the third node C are also gradually increased, as shown in fig. 6; the operational amplifier 52 in the linear regulated voltage 5 then outputs a low level voltage to lower the node four D to a certain value when the valley voltage of the node two B is not less than the reference voltage Vref (as shown in fig. 7), so that the voltage of the node six F also becomes a certain value, as shown in fig. 8. In this way, the light-emitting element 380 can stably emit light with brightness, and the switch 22 can be switched between on and off with a fixed duty cycle to stabilize the voltage of the first node a, and simultaneously keep the valley voltage of the second node B not less than the reference voltage Vref, as shown in fig. 8, thereby achieving the effect of preventing the led light string 7 from stroboscopic.
Claims (10)
1. A non-stroboscopic light-emitting diode driving device is characterized in that: the device comprises a power supply conversion circuit, a feedback circuit and a linear voltage stabilizing circuit;
the power conversion circuit comprises an alternating current-to-direct current converter which converts alternating current power to generate input voltage; a transformer having a primary coil and a secondary coil isolated from each other and electromagnetically coupled to each other, the primary coil being electrically connected to the AC-DC converter; a changeover switch electrically connected to the primary coil; the controller is electrically connected with the change-over switch and is used for modulating the working period of the change-over switch; and an output stage rectifier electrically connected to the secondary coil and providing output voltage with ripple to the LED string;
the feedback circuit is electrically connected with the output stage rectifier and generates a feedback signal according to the state of the light-emitting diode lamp string to serve as a basis for the controller to modulate the change-over switch;
the linear voltage stabilizing circuit is electrically connected with the output stage rectifier, the feedback circuit and the light emitting diode lamp string, and adjusts the output voltage according to the voltage difference between the output voltage and the cross voltage of the light emitting diode lamp string.
2. The non-strobe led driving apparatus of claim 1, wherein: the linear voltage stabilizing circuit comprises a transistor, a capacitor, a first resistor, a second resistor and a sampling unit; the first resistor is bridged between the capacitor and the current output end of the transistor; a second resistor electrically connected to the capacitor and the feedback circuit; the current source is electrically connected to the light-emitting diode lamp string; the sampling unit is electrically connected with the light-emitting diode lamp string and the current source and is used for sampling the voltage passing through the light-emitting diode lamp string to generate a sampling signal; and the operational amplifier compares the sampling signal with the reference voltage and provides a signal to reduce the on-resistance value of the transistor to change the feedback signal when the sampling signal is smaller than the reference voltage.
3. The non-strobe led driving apparatus according to claim 2, wherein: the operational amplifier provides another signal to maintain the on-resistance of the transistor when the sampling signal is equal to the reference voltage.
4. The non-strobe led driving apparatus according to claim 2, wherein: the feedback circuit comprises an optical coupler, a current-limiting resistor, a voltage stabilizer, a first voltage-stabilizing resistor and a second voltage-stabilizing resistor; the optical coupler comprises a light emitting piece and a light receiving piece, and the light emitting piece and the light receiving piece are used as the basis for providing the feedback signal according to the brightness of the light emitting piece; the current limiting resistor is bridged between the output-stage rectifier and the light-emitting element; the voltage stabilizer is electrically connected between the light-emitting piece and the grounding end; a first voltage stabilizing resistor connected across the output stage rectifier and a control terminal of the voltage stabilizer; and the second voltage stabilizing resistor is connected with the first voltage stabilizing resistor in series, wherein when the sampling signal is less than the reference voltage, the brightness of the luminous element is increased to change the feedback signal so as to lead the working period of the lifting switch of the switch to be increased.
5. The non-strobe led driving apparatus of claim 1, wherein: the power conversion circuit further comprises a vibration damping unit electrically connected to the AC-DC converter, the primary coil and the change-over switch, wherein the vibration damping unit suppresses voltage stress on the change-over switch by absorbing a voltage surge derived from a leakage inductance of the transformer.
6. The non-strobe led driving apparatus as claimed in claim 5, wherein: the vibration damping unit comprises a diode, a resistor and a capacitor; the diode is electrically connected to the AC-DC converter; the resistor is connected in series with the diode; and the capacitor is connected in parallel with the resistor.
7. The non-strobe led driving apparatus of claim 1, wherein: the power conversion circuit further comprises an electromagnetic interference filter, an input stage capacitor and an output stage capacitor; the electromagnetic interference filter is electrically connected with the alternating current-direct current converter to filter electromagnetic noise in alternating current power; the input stage capacitor is electrically connected between the alternating current-direct current converter and the primary coil; and the output stage capacitor is electrically connected between the output stage rectifier and the feedback circuit.
8. A linear voltage stabilizing method of a non-stroboscopic light-emitting diode driving device is characterized in that: includes providing an output voltage with a ripple to a load; providing a feedback signal when a low valley voltage after passing through the load is less than the reference voltage; and linearly adjusting the level of the output voltage according to the feedback signal.
9. The linear voltage stabilizing method of the stroboflash-free LED driving device as claimed in claim 8, wherein: also included is providing a feedback signal to maintain the level of the output voltage when the valley voltage after passing through the load is equal to the reference voltage.
10. The linear voltage stabilizing method of the stroboflash-free LED driving device as claimed in claim 8, wherein: also included is receiving the ac power and converting the ac power to the output voltage.
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| CN112688381A (en) * | 2020-12-15 | 2021-04-20 | Oppo广东移动通信有限公司 | Charging circuit, circuit control method and electronic equipment |
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| CN103857149A (en) * | 2012-11-30 | 2014-06-11 | 硅工厂股份有限公司 | LED lighting apparatus, current regulator for the LED lighting apparatus, and current regulation method of the LED lighting apparatus |
| US20150002044A1 (en) * | 2013-06-28 | 2015-01-01 | University Of Seoul Industry Cooperation Foundation | Power supply device and control circuit thereof |
| CN105517274A (en) * | 2014-10-08 | 2016-04-20 | 光明电子股份有限公司 | driving circuit of light emitting diode and light emitting device thereof |
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|---|---|---|---|---|
| CN103857149A (en) * | 2012-11-30 | 2014-06-11 | 硅工厂股份有限公司 | LED lighting apparatus, current regulator for the LED lighting apparatus, and current regulation method of the LED lighting apparatus |
| US20150002044A1 (en) * | 2013-06-28 | 2015-01-01 | University Of Seoul Industry Cooperation Foundation | Power supply device and control circuit thereof |
| CN105517274A (en) * | 2014-10-08 | 2016-04-20 | 光明电子股份有限公司 | driving circuit of light emitting diode and light emitting device thereof |
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| CN112688381A (en) * | 2020-12-15 | 2021-04-20 | Oppo广东移动通信有限公司 | Charging circuit, circuit control method and electronic equipment |
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Application publication date: 20200211 |