WO2020052223A1 - 恒功率led驱动电路及led驱动电源 - Google Patents

恒功率led驱动电路及led驱动电源 Download PDF

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Publication number
WO2020052223A1
WO2020052223A1 PCT/CN2019/080579 CN2019080579W WO2020052223A1 WO 2020052223 A1 WO2020052223 A1 WO 2020052223A1 CN 2019080579 W CN2019080579 W CN 2019080579W WO 2020052223 A1 WO2020052223 A1 WO 2020052223A1
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Prior art keywords
terminal
resistor
circuit
output
voltage
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PCT/CN2019/080579
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English (en)
French (fr)
Inventor
邹超洋
王宗友
莫永福
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深圳市崧盛电子股份有限公司
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Publication of WO2020052223A1 publication Critical patent/WO2020052223A1/zh

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]

Definitions

  • the present invention relates to the technical field of driving power sources, and more particularly, to a constant power LED driving circuit and an LED driving power source.
  • a power supply In daily life, a power supply is generally used to convert a commercially available AC power source (such as AC power from a commercial power outlet) into a DC power source for use by an electrical device.
  • a conversion technology of a power supply used in a personal computer is based on a switching operation using a switching device to provide a variety of predetermined prepared DC output voltages.
  • This type of power supply is commonly referred to as a switching (or switching) power supply.
  • LED drive power refers to a power supply that converts external primary energy into secondary energy required by the LED.
  • the input power of the LED driving power includes AC power and DC power, and the output power is generally a constant current that can change the voltage as the LED forward voltage changes.
  • LED drive power is mainly used in the fields of LED lighting, LED display and LED backlight. Among them, LED lighting has the highest requirements for drive control technology. It is currently the main application area of LED drive power and has the broadest market prospects. The stability of the driving power quality is a key factor in the service life of LED lighting fixtures.
  • the existing constant power power supply technology mainly sets a voltage range artificially, and then adjusts the output current value, and then manually calculates the power obtained by multiplying the output voltage by the current to determine whether it exceeds the maximum output of the power supply. Power value.
  • the output of the traditional LED power supply consists of two independent units: constant current control and constant voltage control.
  • constant current control When adjusting the output constant current, the constant voltage control is not affected. Because the current specifications of the client lamps and lanterns are different, products must be designed. It is convenient for customers to make adjustments in the application. The reserved current is adjustable. When the output current is increased, there is a risk of overpower application during use because the voltage does not change.
  • a technical problem to be solved by the present invention is to provide a constant-power LED driving circuit and an LED driving power source in response to the foregoing defects of the prior art.
  • the technical solution adopted by the present invention to solve its technical problems is to construct a constant power LED driving circuit, including: AC-DC conversion circuit, reference setting circuit, current sampling circuit, voltage sampling circuit, signal processing circuit, and constant power Regulating circuit
  • the positive output terminal of the AC-DC conversion circuit is connected to the input terminal of the reference setting circuit and the input terminal of the voltage sampling circuit, and the negative output terminal of the AC-DC conversion circuit is connected to the current sampling circuit.
  • the input terminal; the current reference terminal of the reference setting circuit is connected to the input terminal of the signal processing circuit, the voltage reference terminal of the reference setting circuit is connected to the voltage input terminal of the voltage sampling circuit;
  • the output terminal is connected to the output terminal of the voltage sampling circuit, and then connected to the first input terminal of the constant power adjustment circuit; the output terminal of the signal processing circuit is connected to the second input terminal of the constant power adjustment circuit;
  • the constant power adjustment circuit is further connected to a feedback terminal of the AC-DC conversion circuit;
  • the AC-DC conversion circuit is used for converting AC power to DC power and outputting the DC power to a load
  • the reference setting circuit is used for generating a reference signal
  • the current sampling circuit is used for collecting the AC-DC conversion The current signal output from the circuit and the amplification process, and outputting the amplified current signal to the constant power adjustment circuit
  • the voltage sampling circuit is used to collect the voltage signal output by the AC-DC conversion circuit and collect the collected voltage
  • a signal is output to the constant power adjusting circuit
  • the dimming circuit is configured to receive and process a dimming signal, and transmit the processed dimming signal to the signal processing circuit
  • the signal processing circuit is configured to receive the dimming signal
  • the reference signal output by the reference setting circuit outputs a DC signal to the constant power adjustment circuit
  • the constant power adjustment circuit is configured to output a feedback signal to the AC-DC conversion according to the received current signal, voltage signal, and DC signal Circuit so that the AC-DC conversion circuit maintains a constant power output.
  • it further comprises: a dimming circuit connected to the signal processing circuit;
  • the dimming circuit is used for receiving and processing a dimming signal, and transmitting the processed dimming signal to the signal processing circuit.
  • the reference setting circuit includes: a linear voltage stabilization circuit, a voltage generating circuit, and a reference signal generating circuit;
  • An input terminal of the linear voltage stabilization circuit is connected to a positive output terminal of the AC-DC conversion circuit, an output terminal of the linear voltage stabilization circuit is connected to an input terminal of the voltage generation circuit, and an output terminal of the voltage generation circuit is connected
  • An input terminal of the linear voltage stabilization circuit is an input terminal of the reference setting circuit, and a first output terminal of the reference signal generating circuit is a current reference terminal of the reference setting circuit.
  • the second output terminal is a voltage reference terminal of the reference setting circuit.
  • the linear voltage stabilization circuit includes: a resistor R5, a transistor Q2, a voltage regulator ZD1, and an electrolytic capacitor CE3;
  • a first end of the resistor R5 and a collector of the transistor Q2 are connected together to a positive output terminal of the AC-DC conversion circuit, and a second end of the resistor R5 is connected to a base of the transistor Q2 together.
  • the anode of the Zener ZD1, the anode of the Zener ZD1 and the second end of the electrolytic capacitor CE3 are grounded together, the emitter of the transistor Q2 and the first end of the electrolytic capacitor CE3 are together Connected to an input terminal of the voltage generating circuit;
  • the first terminal of the resistor R5 and the collector of the transistor Q2 are the input terminals of the linear voltage regulator circuit, and the emitter of the transistor Q2 and the first terminal of the electrolytic capacitor CE3 are the linear voltage regulator. Output of the circuit.
  • the voltage generating circuit includes: a resistor R6, a reference voltage regulator U2, a resistor R7, a resistor R8, and a capacitor C2;
  • the first terminal of the resistor R6 is connected to the input terminal of the linear voltage regulator circuit, and the second terminal of the resistor R6 is connected to the third terminal of the reference voltage regulator U2, the first terminal of the resistor R7, and The first terminal of the capacitor C2, the second terminal of the reference regulator U2, the second terminal of the resistor R8, and the second terminal of the capacitor C2 are grounded together.
  • the first terminal is connected to the second terminal of the resistor R7 and the first terminal of the resistor R8; the connection terminal of the second terminal of the resistor R6 and the first terminal of the capacitor C2 is also connected to the reference signal generating circuit Input
  • a first terminal of the resistor R6 is an input terminal of the voltage generating circuit, and a connection terminal of a second terminal of the resistor R6 and a first terminal of the capacitor C2 is an output terminal of the voltage generating circuit.
  • the reference signal generating circuit includes: a resistor R9, an adjustable potentiometer VR1, and a resistor R10;
  • a first terminal of the resistor R9 is connected to an output terminal of the voltage generating circuit, a second terminal of the resistor R9 is connected to a first terminal of the adjustable potentiometer VR1, and a second terminal of the adjustable potentiometer VR1
  • the first end of the resistor R10 is connected, and the second end of the resistor R10 is grounded; the connection end of the second end of the resistor R9 and the first end of the adjustable potentiometer VR1 is also connected to the signal processing circuit.
  • An input terminal, a connection terminal of the second terminal of the adjustable potentiometer VR1 and a first terminal of the resistor R10 is further connected to a reference voltage terminal of the voltage sampling circuit;
  • connection end of the second end of the resistor R9 and the first end of the adjustable potentiometer VR1 is the first output end of the reference signal generating circuit
  • the second end of the adjustable potentiometer VR1 and the A connection end of a first end of the resistor R10 is a second output end of the reference signal generating circuit.
  • the signal processing circuit includes: a resistor R24, a resistor R25, an operational amplifier U5-A, a resistor R26, and a capacitor C4;
  • a first terminal of the resistor R24 is connected to a current reference terminal of the reference setting circuit, a second terminal of the resistor R24 is grounded through the capacitor C4, and a connection terminal of the resistor R24 and the capacitor C4 passes through the
  • the resistor R25 is connected to the positive input terminal of the operational amplifier U5-A, the negative input terminal of the operational amplifier U5-A is short-circuited to its output terminal, and the output terminal of the operational amplifier U5-A is connected to the first of the resistor R26 Terminal, the second terminal of the resistor R26 is connected to the second input terminal of the constant power adjustment circuit; at this time, the first terminal of the resistor R24 is the input terminal of the signal processing circuit, and the resistance of the resistor R26 is The second terminal is an output terminal of the signal processing circuit;
  • the signal processing circuit includes a photocoupler OT2-B, a resistor R21, a resistor R22, a MOS tube Q3, a resistor R23, a resistor R24, a resistor R25, a capacitor C4, an operational amplifier U5-A, and a resistor R26;
  • the photocoupler OT2-B is coupled to the dimming circuit, the third terminal of the photocoupler OT2-B is grounded, and the fourth terminal of the photocoupler OT2-B is connected to the connection node of the resistor R21 and the resistor R22 and connected to The base of the MOS transistor Q3, the first terminal of the resistor R21 is connected to VCC, the second terminal of the resistor R22 is grounded, and the drain of the MOS transistor Q3 is connected to the second terminal of the resistor R23. The source of the MOS transistor Q3 is grounded.
  • the first terminal of the resistor R23 is connected to the current reference terminal of the reference setting circuit.
  • the first terminal of the resistor R24 is connected to the first terminal of the resistor R23.
  • the resistor R24 The second terminal of the capacitor is grounded through the capacitor C4, and the connection terminal of the resistor R24 and the capacitor C4 is connected to the positive input terminal of the operational amplifier U5-A through the resistor R25, and the negative terminal of the operational amplifier U5-A
  • the input terminal is short-circuited with its output terminal, the output terminal of the operational amplifier U5-A is connected to the first terminal of the resistor R26, and the second terminal of the resistor R26 is connected to the second input terminal of the constant power adjustment circuit;
  • An input terminal of the processing circuit, and a second terminal of the resistor R26 is an output terminal of the signal processing circuit.
  • the current sampling circuit includes: a resistor R11, a resistor R12, a resistor R13, a resistor R14, an operational amplifier U4-A, and a resistor R15;
  • the first terminal of the resistor R11 is grounded, the second terminal of the resistor R11 is connected to the output terminal of the operational amplifier U4-A through the resistor R14, and the second terminal of the resistor R11 is also connected to the operational amplifier U4.
  • -A negative input terminal the first terminal of the resistor R12 is connected to the negative output terminal of the AC-DC conversion circuit, and the second terminal of the resistor R12 is connected to the positive input terminal of the operational amplifier U4-A.
  • the positive input terminal of the operational amplifier U4-A is also grounded through the resistor R13, the output terminal of the operational amplifier U4-A is connected to the first terminal of the resistor R15, and the second terminal of the resistor R15 is connected to the constant A first input terminal of the power adjustment circuit;
  • a first terminal of the resistor R12 is an input terminal of the current sampling circuit, and a second terminal of the resistor R15 is an output terminal of the current sampling circuit;
  • the voltage sampling circuit includes: a resistor R16, a resistor R17, a resistor R18, a resistor R19, a capacitor C3, a resistor R20, and an operational amplifier U4-B;
  • a first terminal of the resistor R16 is connected to a positive output terminal of the AC-DC conversion circuit, and a second terminal of the resistor R16 is connected to a positive input terminal of the operational amplifier U4-B.
  • the positive input terminal is also grounded through the resistor R17, the first terminal of the resistor R18 is connected to the voltage reference terminal of the reference setting circuit, and the second terminal of the resistor R18 is connected to the negative input of the operational amplifier U4-B.
  • Terminal, the second terminal of the resistor R18 is also connected to the output terminal of the operational amplifier U4-B through the capacitor C3 and the resistor R19 in order, and the output terminal of the operational amplifier U4-B is connected to the resistor R20.
  • First end, the second end of the resistor R20 is connected to the output end of the current sampling circuit and also connected to the first input end of the constant power adjustment circuit;
  • a first terminal of the resistor R16 is an input terminal of the voltage sampling circuit
  • a first terminal of the resistor R18 is a voltage input terminal of the voltage sampling circuit
  • a second terminal of the resistor R20 is the voltage sampling. Output of the circuit.
  • the constant power adjustment circuit includes: a capacitor C5, a resistor R27, a resistor R28, a photocoupler OT1-A, and an operational amplifier U5-B;
  • the capacitor C5 is connected in series with the resistor R27, it is connected in parallel between the negative input terminal and the output terminal of the operational amplifier U5-B, and the negative input terminal of the operational amplifier U5-B is also connected to the current sampling circuit.
  • An output terminal and an output terminal of a voltage sampling circuit a positive input terminal of the operational amplifier U5-B is connected to an output terminal of the signal processing circuit, and an output terminal of the operational amplifier U5-B is connected to the photoelectricity through the resistor R28
  • a second end of the coupler OT1-A, a first end of the photocoupler OT1-A is connected to VCC, and the photocoupler OT1-A is coupled to a feedback end of the AC-DC conversion circuit;
  • the negative input terminal of the operational amplifier U5-B is the first input terminal of the constant power adjustment circuit, and the positive input terminal of the operational amplifier U5-B is the second input terminal of the constant power adjustment circuit.
  • the present invention also provides an LED driving power supply, including the constant power LED driving circuit described above.
  • the implementation of the constant-power LED driving circuit of the present invention has the following beneficial effects:
  • the present invention can realize automatic adjustment of output voltage and output current to achieve constant power output, and the output power is independent of the input voltage, which can greatly improve the applicable field of LED driving power.
  • the constant power LED driving circuit of the present invention adopts a method of automatically detecting voltage and current, automatically adjusting output voltage and output voltage, and performing constant power control to achieve the purpose of constant power output, which can effectively save labor costs, and at the same time can also Avoid misoperation caused by human operation.
  • FIG. 1 is a schematic structural diagram of a first embodiment of a constant power LED driving circuit according to the present invention
  • FIG. 2 is a schematic structural diagram of a second embodiment of a constant power LED driving circuit according to the present invention.
  • FIG. 3 is a circuit schematic diagram of a constant power LED driving circuit according to an embodiment of the present invention.
  • the constant power LED driving circuit includes an AC-DC conversion circuit 10, a reference setting circuit 20, a current sampling circuit 40, a voltage sampling circuit 50, a signal processing circuit 60, and a constant power adjustment circuit 70.
  • the positive output terminal (LED +) of the AC-DC conversion circuit 10 is connected to the input terminal of the reference setting circuit 20 and the input terminal of the voltage sampling circuit 50, and the negative output terminal (LED-) of the AC-DC conversion circuit 10 is connected to the current.
  • the input terminal of the sampling circuit 40; the current reference terminal of the reference setting circuit 20 is connected to the input terminal of the signal processing circuit 60; the voltage reference terminal of the reference setting circuit 20 is connected to the voltage input terminal of the voltage sampling circuit 50; the output of the current sampling circuit 40 After the terminal is connected to the output terminal of the voltage sampling circuit 50, it is connected to the first input terminal of the constant power adjustment circuit 70; the output terminal of the signal processing circuit 60 is connected to the second input terminal of the constant power adjustment circuit 70; the constant power adjustment circuit 70 also The feedback terminal of the AC-DC conversion circuit 10 is connected.
  • the AC-DC conversion circuit 10 is configured to convert AC power to DC power and output the DC power to a load.
  • the reference setting circuit 20 is used to generate a reference signal.
  • the reference signal generated by the reference setting circuit 20 includes a current reference signal and a voltage reference signal.
  • the output current and voltage of the LED driving power can be controlled by generating the corresponding current reference signal and voltage reference signal through the reference setting circuit 20.
  • the current sampling circuit 40 is configured to collect and process the current signal output from the AC-DC conversion circuit 10 and output the amplified current signal to the constant power adjustment circuit 70.
  • the current sampling circuit 40 may amplify the collected current signal according to a certain ratio and then transmit the amplified current signal to the constant power adjustment circuit 70.
  • the constant power adjustment circuit 70 performs corresponding comparison amplification processing and feeds back to AC-
  • the DC conversion circuit 10 adjusts the output current of the AC-DC conversion circuit 10 to achieve the purpose of automatically adjusting the output current of the LED driving power.
  • the output current of the AC-DC conversion circuit 10 is the output current of the LED driving power.
  • the voltage sampling circuit 50 is configured to collect a voltage signal output from the AC-DC conversion circuit 10 and output the collected voltage signal to the constant power adjustment circuit 70.
  • the voltage sampling circuit 50 can feedback the voltage value of the voltage signal output by the AC-DC conversion circuit 10 and the change situation of the voltage signal by means of resistance voltage division, and transmit the feedback voltage value or the change situation of the voltage signal to the constant
  • the power adjustment circuit 70 adjusts the voltage signal output by the AC-DC conversion circuit 10, that is, adjusts the output voltage of the LED driving power source, and automatically adjusts the output voltage of the LED driving power source.
  • the output voltage of the AC-DC conversion circuit 10 is the output voltage of the LED driving power.
  • the signal processing circuit 60 is configured to process and convert the received reference signal output from the reference setting circuit 20 into a DC signal, and send the DC signal to the constant power adjustment circuit 70.
  • the constant power adjustment circuit 70 is configured to output a feedback signal to the AC-DC conversion circuit 10 according to the received current signal, voltage signal, and DC signal, so that the AC-DC conversion circuit 10 maintains constant power output.
  • the AC-DC conversion circuit 10 can adjust the output current of the LED driving power according to the actual output signals (voltage signal and current signal) of the LED driving power so that LED drive power supplies achieve the purpose of constant power output.
  • FIG. 2 is a schematic structural diagram of a constant power LED driving circuit according to a second embodiment of the present invention.
  • this embodiment further includes a dimming circuit 30.
  • the dimming circuit 30 is connected to the signal processing circuit 60 for receiving and processing the dimming signal, and transmitting the processed dimming signal to the signal processing circuit 60.
  • the dimming circuit 30 can process different dimming signals (such as any one or more of a resistance dimming signal, a voltage dimming signal, and a PWM dimming signal) into a linearly varying PWM dimming signal.
  • the dimming signal is provided by an external circuit.
  • the signal processing circuit 60 mainly converts the linearly-varying PWM signal output from the dimming circuit 30 into a DC signal with a certain ratio, and sends it to the constant power adjusting circuit 70.
  • the constant power LED driving circuit of the present invention can adjust the output current of the LED driving power according to different dimming signals, so that the LED driving power can act on different dimming signals. Can still achieve constant power output.
  • FIG. 3 a schematic circuit diagram of a preferred embodiment of a constant power LED driving circuit according to an embodiment of the present invention, wherein the circuit schematic is a dimming constant power output, that is, the constant power can be adjusted according to different dimming.
  • the signal regulates the output current of the LED driving power, so that the LED driving power can still achieve constant power output under the effect of different dimming signals.
  • the AC-DC conversion circuit 10 includes a fuse F1, a common mode inductor LF1, a rectifier bridge BD1, an electrolytic capacitor CE1, a diode D2, an electrolytic capacitor CE2, a switching MOS transistor Q1, a resistor R4, Photocoupler OT1-B and control IC U1.
  • the alternating current AC passes the fuse F1 and the common mode inductance LF1 to the rectifier bridge BD1, the rectified voltage is filtered by the electrolytic capacitor CE1 to filter the DC voltage, and the filtered DC voltage is coupled to the secondary side through a transformer in a certain proportion.
  • the secondary is rectified by the diode D2, and the electrolytic capacitor CE2 filters the DC output voltage and current.
  • the switching MOS tube Q1 controls the output voltage and output current according to the switching PWM signal.
  • the photocoupler OT1-B controls the feedback terminal of the control IC U1.
  • the control IC U1 outputs a PWM signal to the resistor R3 to control the duty ratio of the switching MOS tube Q1 according to the feedback signal from the feedback terminal, thereby achieving the purpose of stabilizing the output voltage and current and achieving constant power output.
  • the reference setting circuit 20 includes: a linear voltage stabilization circuit 201, a voltage generating circuit 202, and a reference signal generating circuit 203.
  • the input terminal of the linear voltage regulator circuit 201 is connected to the positive output terminal of the AC-DC conversion circuit 10, the output terminal of the linear voltage regulator circuit 201 is connected to the input terminal of the voltage generating circuit 202, and the output terminal of the voltage generating circuit 202 is connected to the reference signal generating circuit 203.
  • the first output terminal of the reference signal generating circuit 203 is connected to the input terminal of the signal processing circuit 60, and the second output terminal of the reference signal generating circuit 203 is connected to the reference voltage terminal of the voltage sampling circuit 50;
  • the input of the linear regulator circuit 201 Terminal is the input terminal of the reference setting circuit 20
  • the first output terminal of the reference signal generating circuit 203 is the current reference terminal of the reference setting circuit 20
  • the second output terminal of the reference signal generating circuit 203 is the voltage of the reference setting circuit 20. Reference end.
  • the linear voltage stabilization circuit 201 includes a resistor R5, a transistor Q2, a voltage regulator ZD1, and an electrolytic capacitor CE3.
  • the first end of the resistor R5 and the collector of the transistor Q2 are connected to the positive output terminal of the AC-DC conversion circuit 10, and the second end of the resistor R5 and the base of the transistor Q2 are connected to the negative electrode of the zener tube ZD1 to stabilize the voltage.
  • the anode of the tube ZD1 and the second end of the electrolytic capacitor CE3 are grounded together.
  • the emitter of the transistor Q2 and the first end of the electrolytic capacitor CE3 are connected to the input terminal of the voltage generating circuit 202 together.
  • the first end of the resistor R5 is connected to the transistor Q2.
  • the collector is the input terminal of the linear voltage stabilization circuit 201, and the emitter of the transistor Q2 and the first end of the electrolytic capacitor CE3 are the output terminals of the linear voltage stabilization circuit 201.
  • the voltage generating circuit 202 includes a resistor R6, a reference voltage regulator U2, a resistor R7, a resistor R8, and a capacitor C2.
  • the first terminal of the resistor R6 is connected to the input terminal of the linear voltage regulator circuit 201, and the second terminal of the resistor R6 is respectively connected to the third terminal of the reference voltage regulator U2, the first terminal of the resistor R7 and the first terminal of the capacitor C2, and the reference is stable.
  • the second terminal of the voltage regulator U2 and the second terminal of the resistor R8 and the second terminal of the capacitor C2 are grounded together.
  • the first terminal of the reference voltage regulator U2 is connected to the second terminal of the resistor R7 and the first terminal of the resistor R8;
  • the connection between the second end of R6 and the first end of capacitor C2 is also connected to the input of reference signal generating circuit 203;
  • the first end of resistor R6 is the input of voltage generating circuit 202, the second end of resistor R6 and capacitor C2
  • the connection end of the first end is an output end of the voltage generating circuit 202.
  • the reference signal generating circuit 203 includes a resistor R9, an adjustable potentiometer VR1, and a resistor R10.
  • the first terminal of the resistor R9 is connected to the output terminal of the voltage generating circuit 202, the second terminal of the resistor R9 is connected to the first terminal of the adjustable potentiometer VR1, and the second terminal of the adjustable potentiometer VR1 is connected to the first terminal of the resistor R10.
  • the second end of R10 is grounded; the connection end of the second end of resistor R9 and the first end of adjustable potentiometer VR1 is also connected to the input end of signal processing circuit 60, the second end of adjustable potentiometer VR1 and the first end of resistor R10 One terminal is also connected to the reference voltage terminal of the voltage sampling circuit 50; the second terminal of the resistor R9 and the first terminal of the adjustable potentiometer VR1 is the first output terminal of the reference signal generating circuit 203, the adjustable potential
  • the connection terminal of the second terminal of the resistor VR1 and the first terminal of the resistor R10 is the second output terminal of the reference signal generating circuit 203.
  • a stable voltage VCC is output.
  • the stable voltage VCC passes a resistor R6, a reference voltage regulator U2 (TL431), a resistor R7, a resistor R8, and a capacitor C2 to generate a stable reference voltage.
  • the stable reference voltage outputs a current reference signal (IREF) and a voltage reference signal (VREF) through a resistor R9, an adjustable potentiometer VR1, and a resistor R10.
  • the current reference signal (IREF) and the voltage reference signal (VREF) are obtained by the constant proportional change of the adjustable potentiometer VR1. You can set the constant maximum when the adjustable potentiometer VR1 is at a certain potentiometer value. Output voltage and maximum output current to achieve constant output power.
  • the stable voltage VCC is also transmitted to the control IC U1 and other circuits inside the LED driving power supply, and is used as a power supply voltage for the control IC U1 and other circuits inside the LED driving power supply.
  • the signal processing circuit 60 includes a photocoupler OT2-B, a resistor R21, a resistor R22, a MOS tube Q3, a resistor R23, a resistor R24, a resistor R25, a capacitor C4, an operational amplifier U5-A, and a resistor R26;
  • the photocoupler OT2-B is coupled to the dimming circuit 30.
  • the third terminal of the photocoupler OT2-B is grounded.
  • the fourth terminal of the photocoupler OT2-B is connected to the connection node of the resistor R21 and the resistor R22 and is connected to the MOS tube Q3.
  • the first terminal of resistor R21 is connected to VCC
  • the second terminal of resistor R22 is connected to ground
  • the drain of MOS transistor Q3 is connected to the second terminal of resistor R23
  • the source of MOS transistor Q3 is connected to ground
  • the first terminal of resistor R23 is connected
  • the current reference terminal of the reference setting circuit 20 the first terminal of the resistor R24 is connected to the first terminal of the resistor R23, the second terminal of the resistor R24 is grounded through the capacitor C4, and the connection terminal of the resistor R24 and the capacitor C4 is connected to the operational amplifier U5 through the resistor R25.
  • the negative input terminal of the operational amplifier U5-A is shorted to its output terminal
  • the output terminal of the operational amplifier U5-A is connected to the first terminal of the resistor R26
  • the second terminal of the resistor R26 is connected to the constant power regulating circuit 70
  • the second terminal of the resistor R23 and the first terminal of the resistor R24 are connected to the input terminal of the signal processing circuit 60
  • the second terminal of the resistor R26 is the output terminal of the signal processing circuit 60.
  • the stable voltage VCC passes through the resistor R21, resistor R22, the photocoupler OT2-B to the base (drive pin) of the MOS tube Q3, and the drain of the MOS tube Q3 is connected to the resistor R23 to the current reference signal (IREF).
  • the resistor R23 mainly plays the role of setting the minimum dimming output current.
  • the photocoupler OT2-B receives the linear dimming signal (PWM signal) output from the dimming circuit 30 and passes the PWM signal through the MOS tube Q3 to make the current reference signal (IREF) on the first end of the resistor R23 constant Amplitude PWM voltage. This constant amplitude PWM voltage is filtered to a DC voltage through resistor R24 and capacitor C4.
  • the DC voltage is connected to the positive input of the operational amplifier U5-A through resistor R25.
  • U5-A implements voltage follow-up and outputs a DC voltage.
  • the signal passes through the resistor R26 to the positive input terminal of the operational amplifier U5-B (that is, the second input terminal of the constant power adjustment circuit 70).
  • the signal processing circuit 60 when the constant power LED driving circuit is a non-dimming constant power output LED driving circuit, the signal processing circuit 60 only includes a resistor R24, a resistor R25, and an operational amplifier U5. -A, resistor R26 and capacitor C4.
  • the first terminal of the resistor R24 is connected to the current reference terminal of the reference setting circuit 20, the second terminal of the resistor R24 is grounded through the capacitor C4, and the connection terminals of the resistor R24 and the capacitor C4 are connected to the positive input of the operational amplifier U5-A through the resistor R25.
  • the negative input terminal of the operational amplifier U5-A is shorted to its output terminal, the output terminal of the operational amplifier U5-A is connected to the first terminal of the resistor R26, and the second terminal of the resistor R26 is connected to the second input terminal of the constant power adjustment circuit;
  • the first terminal of the resistor R24 is an input terminal of the signal processing circuit 60, and the second terminal of the resistor R26 is an output terminal of the signal processing circuit 60;
  • the resistor R24 is 0 ohms.
  • the current sampling circuit 40 includes a resistor R11, a resistor R12, a resistor R13, a resistor R14, an operational amplifier U4-A, and a resistor R15.
  • the first terminal of the resistor R11 is grounded.
  • the second terminal of the resistor R11 is connected to the output terminal of the operational amplifier U4-A through the resistor R14.
  • the second terminal of the resistor R11 is also connected to the negative input terminal of the operational amplifier U4-A.
  • Terminal is connected to the negative output terminal of the AC-DC conversion circuit 10
  • the second terminal of the resistor R12 is connected to the positive input terminal of the operational amplifier U4-A
  • the positive input terminal of the operational amplifier U4-A is also grounded through the resistor R13
  • the operational amplifier U4-A The output terminal of the resistor R15 is connected to the first terminal of the resistor R15, and the second terminal of the resistor R15 is connected to the first input terminal of the constant power adjustment circuit 70;
  • the first terminal of the resistor R12 is the input terminal of the current sampling circuit 40, and the second terminal of the resistor R15 Is the output terminal of the current sampling circuit 40.
  • the signal of the negative output terminal of the AC-DC conversion circuit 10 passes the resistor R12 and resistor R13 to the positive input terminal of the operational amplifier U4-A, the negative input terminal of U4-A is grounded by the resistor R11, and the negative of U4-A
  • the input terminal is connected to the resistor R14, so that a small current signal is sampled and amplified to a voltage of a certain ratio through the operational amplifier U4-A.
  • the ratio voltage is output to the negative input terminal of the operational amplifier U5-B through the resistor R15 (ie, the constant power adjustment circuit 70). First input).
  • the voltage sampling circuit 50 includes a resistor R16, a resistor R17, a resistor R18, a resistor R19, a capacitor C3, a resistor R20, and an operational amplifier U4-B.
  • the first terminal of the resistor R16 is connected to the positive output terminal of the AC-DC conversion circuit 10
  • the second terminal of the resistor R16 is connected to the positive input terminal of the operational amplifier U4-B
  • the positive input terminal of the operational amplifier U4-B is also grounded through the resistor R17.
  • the first terminal of the resistor R18 is connected to the voltage reference terminal of the reference setting circuit 20
  • the second terminal of the resistor R18 is connected to the negative input terminal of the operational amplifier U4-B
  • the second terminal of the resistor R18 is connected to the operation through the capacitor C3 and the resistor R19 in order.
  • the output terminal of the amplifier U4-B, the output terminal of the operational amplifier U4-B is connected to the first terminal of the resistor R20, and the second terminal of the resistor R20 is connected to the output terminal of the current sampling circuit 40 and also connected to the first input of the constant power adjustment circuit 70
  • the first terminal of the resistor R16 is the input terminal of the voltage sampling circuit 50
  • the first terminal of the resistor R18 is the voltage input terminal of the voltage sampling circuit 50
  • the second terminal of the resistor R20 is the output terminal of the voltage sampling circuit 50.
  • the constant power adjusting circuit 70 includes a capacitor C5, a resistor R27, a resistor R28, a photocoupler OT1-A, and an operational amplifier U5-B.
  • the capacitor C5 is connected in series with the resistor R27, and is connected in parallel between the negative input terminal and the output terminal of the operational amplifier U5-B.
  • the negative input terminal of the operational amplifier U5-B is also connected to the output terminal of the current sampling circuit 40 and the output of the voltage sampling circuit 50.
  • the positive input terminal of the operational amplifier U5-B is connected to the output terminal of the signal processing circuit 60, and the output terminal of the operational amplifier U5-B is connected to the second terminal of the photocoupler OT1-A through a resistor R28,
  • the first terminal is connected to VCC, and the photocoupler OT1-A is coupled to the feedback terminal of the AC-DC conversion circuit 10;
  • the negative input terminal of the operational amplifier U5-B is the first input terminal of the constant power adjustment circuit 70, and the operational amplifier U5-B
  • the positive input terminal is the second input terminal of the constant power adjustment circuit 70.
  • the signal output by the current sampling circuit 40 is input to the negative input terminal of the operational amplifier U5-B, the signal output by the voltage sampling circuit 50 is input to the negative input terminal of the operational amplifier U5-B; the direct current output by the signal processing circuit 60
  • the voltage signal is output to the positive input terminal of the operational amplifier U5-B through the resistor R26; the operational amplifier U5-B is used for loop compensation through the resistor R27 and the capacitor C5, and the output terminal of the operational amplifier U5-B is connected to the photocoupler OT1 through the resistor R28 -A, the photo coupler OT1-A couples the feedback signal to the photo coupler OT1-B, the photo coupler OT1-B feeds the feedback signal to the feedback terminal (FB) of the control IC U1, and the control IC U1 according to the feedback
  • the feedback signal at the terminal outputs the PWM signal to the resistor R3 to control the duty cycle of the switching MOS tube Q1, thereby achieving the purpose of stabilizing the output voltage and current,
  • the dimming circuit 30 when the dimming circuit 30 receives any one of a PWM dimming signal, a voltage dimming signal, and a resistance dimming signal, the constant power LED driving circuit of the present invention can stably linearly regulate the output of the LED driving power supply. Voltage and output current to achieve constant power output.
  • the constant power LED driving circuit of the present invention uses an operational amplifier and a pure analog circuit of a sensor, which can realize automatic adjustment of output voltage and output current, and achieve constant output power output through different places of the operational amplifier, and the output power is independent of the input voltage. Can greatly improve the application area of LED drive power.
  • the present invention adopts a design that automatically detects the output voltage and output current, and automatically adjusts the output voltage and output current in real time according to the actual changes in the output voltage and output current to achieve the purpose of constant current output, eliminating the need for manual adjustment and effectively saving labor Cost and can avoid mistakes caused by human operation.
  • the constant-power LED driving circuit of the present invention can also widen the working range of a single LED power supply, so that it can adapt to a wider voltage and current range, thereby reducing the number of models in a single series, more flexibly matching lamps, and reducing The customer's stock.
  • the invention also discloses an LED driving power source, which comprises the aforementioned constant power LED driving circuit.
  • the LED driving power supply can realize constant power output and can automatically adjust the output voltage and output current.

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Abstract

一种恒功率LED驱动电路及LED驱动电源，该驱动电路包括AC-DC转换电路（10）、基准设定电路（20）、电流采样电路（40）、电压采样电路（50）、信号处理电路（60）、以及恒功率调节电路（70）；AC-DC转换电路（10）的正输出端分别连接基准设定电路（20）的输入端和电压采样电路（50）的输入端，AC-DC转换电路（10）的负输出端连接电流采样电路（40）的输入端；基准设定电路（20）的电流基准端连接信号处理电路（60）的输入端，基准设定电路（20）的电压基准端连接电压采样电路（50）的电压输入端；电流采样电路（40）的输出端与电压采样电路（50）的输出端连接后、再连接恒功率调节电路（70）的第一输入端；信号处理电路（60）的输出端连接恒功率调节电路（70）的第二输入端；恒功率调节电路（70）还连接AC-DC转换电路（10）的反馈端。该LED驱动电路可实现恒功率输出，提高电源适用领域。

Description

恒功率LED驱动电路及LED驱动电源 技术领域
本发明涉及驱动电源的技术领域，更具体地说，涉及恒功率LED驱动电路及LED驱动电源。
 背景技术
在日常的生活中，电源供应器一般而言是用来将商业上可利用的交流电源（如来自市电插座的交流电）转换成直流电源，以提供给电器装置来使用。例如，使用在个人电脑中的电源供应器的转换技术是基于利用开关装置的开关操作以提供多种预定准备的直流输出电压。这一类的电源供应器一般称为开关（或称交换式）电源供应器。
LED驱动电源是指将外界一次电能转换为LED所需要二次电能的电源供应器。LED驱动电源的输入电能包括交流电和直流电，而输出电能一般为可随LED正向电压变化而改变电压的恒定电流。LED驱动电源主要应用于LED照明、LED显示屏和LED背光领域，其中，LED照明对于驱动控制技术要求最高，是LED驱动电源目前最主要的应用领域，市场前景最为广阔。驱动电源质量的稳定性是LED照明灯具使用寿命的关键因素。
由于LED灯具行业缺乏统一的标准，所以灯珠的串、并数量设计都是各大厂家自行决定，这就造成了大部分的厂家设计出来的LED灯具模组都不同，这给电源的通用性与匹配性带来了很大的挑战，往往大部分的客户使用的电源都是有不同的输出电压与输出恒流值的要求，给专业电源厂在生产时带来极大的不便。
现有的恒功率电源技术主要是通过人为的设定一个电压范围，然后去调整输出的电流值，再通过人为的去计算输出的电压乘以电流得到的功率，判定是否超出了电源的最大输出功率值。
传统LED电源输出分恒流控制、恒压控制两个独立的单元，在调整输出恒流大小时，恒压控制不受影响，因客户端灯具的电流规格各有不同，产品在设计时均要方便客户应用上作调整预留电流可调，当输出电流调大时，因电压不变，在使用过程中有过功率应用的风险。
另外，采用单片机恒功率电路，由于单片机在恶劣的电磁环境中，以及户外不可预知的温度环境都有可能会造成程序跑飞的现象，或者造成单片机的复位问题，这一直是行业中的难题。
 技术问题
本发明要解决的技术问题在于，针对现有技术的上述缺陷，提供一种恒功率LED驱动电路及LED驱动电源。
 技术解决方案
本发明解决其技术问题所采用的技术方案是：构造一种恒功率LED驱动电路，包括：AC-DC转换电路、基准设定电路、电流采样电路、电压采样电路、信号处理电路、以及恒功率调节电路；
所述AC-DC转换电路的正输出端分别连接所述基准设定电路的输入端和所述电压采样电路的输入端，所述AC-DC转换电路的负输出端连接所述电流采样电路的输入端；所述基准设定电路的电流基准端连接所述信号处理电路的输入端，所述基准设定电路的电压基准端连接所述电压采样电路的电压输入端；所述电流采样电路的输出端与所述电压采样电路的输出端连接后、再连接所述恒功率调节电路的第一输入端；所述信号处理电路的输出端连接所述恒功率调节电路的第二输入端；所述恒功率调节电路还连接所述AC-DC转换电路的反馈端；
所述AC-DC转换电路用于将交流电转换为直流电并将所述直流电输出至负载，所述基准设定电路用于产生基准信号，所述电流采样电路用于对采集所述AC-DC转换电路输出的电流信号及放大处理，并将放大处理的电流信号输出至所述恒功率调节电路；所述电压采样电路用于采集所述AC-DC转换电路输出的电压信号并将所采集的电压信号输出至所述恒功率调节电路，所述调光电路用于接收和处理调光信号、并将处理后的调光信号传送至所述信号处理电路，所述信号处理电路用于接收所述基准设定电路输出的基准信号并输出直流信号至所述恒功率调节电路；所述恒功率调节电路用于根据所接收的电流信号、电压信号、直流信号输出反馈信号至所述AC-DC转换电路，以使所述AC-DC转换电路保持恒功率输出。
优选地，还包括：与所述信号处理电路连接的调光电路；
所述调光电路用于接收和处理调光信号、并将处理后的调光信号传送至所述信号处理电路。
优选地，所述基准设定电路包括：线性稳压电路、电压产生电路、基准信号产生电路；
所述线性稳压电路的输入端连接所述AC-DC转换电路的正输出端，所述线性稳压电路的输出端连接所述电压产生电路的输入端，所述电压产生电路的输出端连接所述基准信号产生电路的输入端，所述基准信号产生电路的第一输出端连接所述信号处理电路的输入端，所述基准信号产生电路的第二输出端连接所述电压采样电路的基准电压端；
所述线性稳压电路的输入端为所述基准设定电路的输入端，所述基准信号产生电路的第一输出端为所述基准设定电路的电流基准端，所述基准信号产生电路的第二输出端为所述基准设定电路的电压基准端。
优选地，所述线性稳压电路包括：电阻R5、三极管Q2、稳压管ZD1、电解电容CE3；
所述电阻R5的第一端和所述三极管Q2的集电极一并连接所述AC-DC转换电路的正输出端，所述电阻R5的第二端和所述三极管Q2的基极一并连接所述稳压管ZD1的负极，所述稳压管ZD1的正极与所述电解电容CE3的第二端一并接地，所述三极管Q2的发射极和所述电解电容CE3的第一端一并连接所述电压产生电路的输入端；
所述电阻R5的第一端和所述三极管Q2的集电极为所述线性稳压电路的输入端，所述三极管Q2的发射极和所述电解电容CE3的第一端为所述线性稳压电路的输出端。
优选地，所述电压产生电路包括：电阻R6、基准稳压器U2、电阻R7、电阻R8和电容C2；
所述电阻R6的第一端连接所述线性稳压电路的输入端，所述电阻R6的第二端分别连接所述基准稳压器U2的第三端、所述电阻R7的第一端和所述电容C2的第一端，所述基准稳压器U2的第二端和所述电阻R8的第二端、所述电容C2的第二端一并接地，所述基准稳压器U2的第一端连接所述电阻R7的第二端和所述电阻R8的第一端；所述电阻R6的第二端和所述电容C2的第一端的连接端还连接所述基准信号产生电路的输入端；
所述电阻R6的第一端为所述电压产生电路的输入端，所述电阻R6的第二端和所述电容C2的第一端的连接端为所述电压产生电路的输出端。
优选地，所述基准信号产生电路包括：电阻R9、可调电位器VR1和电阻R10；
所述电阻R9的第一端连接所述电压产生电路的输出端，所述电阻R9的第二端连接所述可调电位器VR1的第一端，所述可调电位器VR1的第二端连接所述电阻R10的第一端，所述电阻R10的第二端接地；所述电阻R9的第二端和所述可调电位器VR1的第一端的连接端还连接所述信号处理电路的输入端，所述可调电位器VR1的第二端和所述电阻R10的第一端的连接端还连接所述电压采样电路的基准电压端；
所述电阻R9的第二端和所述可调电位器VR1的第一端的连接端为所述基准信号产生电路的第一输出端，所述可调电位器VR1的第二端和所述电阻R10的第一端的连接端为所述基准信号产生电路的第二输出端。
优选地，所述信号处理电路包括：电阻R24、电阻R25、运算放大器U5-A、电阻R26和电容C4；
所述电阻R24的第一端连接所述基准设定电路的电流基准端，所述电阻R24的第二端通过所述电容C4接地，所述电阻R24和所述电容C4的连接端通过所述电阻R25连接所述运算放大器U5-A的正输入端，所述运算放大器U5-A的负输入端与其输出端短接，所述运算放大器U5-A的输出端连接所述电阻R26的第一端，所述电阻R26的第二端连接所述恒功率调节电路的第二输入端；此时，所述电阻R24的第一端为为所述信号处理电路的输入端，所述电阻R26的第二端为所述信号处理电路的输出端；
或者，所述信号处理电路包括光电耦合器OT2-B、电阻R21、电阻R22、MOS管Q3、电阻R23、电阻R24、电阻R25、电容C4、运算放大器U5-A和电阻R26；
光电耦合器OT2-B耦合至调光电路，光电耦合器OT2-B的第三端接地，光电耦合器OT2-B的第四端连接所述电阻R21和所述电阻R22的连接节点并连接至所述MOS管Q3的基极，所述电阻R21的第一端连接VCC，所述电阻R22的第二端接地，所述MOS管Q3的漏极连接所述电阻R23的第二端，所述MOS管Q3的源极接地，所述电阻R23的第一端连接所述基准设定电路的电流基准端，所述电阻R24的第一端连接所述电阻R23的第一端，所述电阻R24的第二端通过所述电容C4接地，所述电阻R24和所述电容C4的连接端通过所述电阻R25连接所述运算放大器U5-A的正输入端，所述运算放大器U5-A的负输入端与其输出端短接，所述运算放大器U5-A的输出端连接所述电阻R26的第一端，所述电阻R26的第二端连接所述恒功率调节电路的第二输入端；此时，所述电阻R23的第一端和所述电阻R24的第一端的连接端为所述信号处理电路的输入端，所述电阻R26的第二端为所述信号处理电路的输出端。
优选地，电流采样电路包括：电阻R11、电阻R12、电阻R13、电阻R14、运算放大器U4-A和电阻R15；
所述电阻R11的第一端接地，所述电阻R11的第二端通过所述电阻R14连接所述运算放大器U4-A的输出端，所述电阻R11的第二端还连接所述运算放大器U4-A的负输入端；所述电阻R12的第一端连接所述AC-DC转换电路的负输出端，所述电阻R12的第二端连接所述运算放大器U4-A的正输入端，所述运算放大器U4-A的正输入端还通过所述电阻R13接地，所述运算放大器U4-A的输出端连接所述电阻R15的第一端，所述电阻R15的第二端连接所述恒功率调节电路的第一输入端；
所述电阻R12的第一端为所述电流采样电路的输入端，所述电阻R15的第二端为所述电流采样电路的输出端；
所述电压采样电路包括：电阻R16、电阻R17、电阻R18、电阻R19、电容C3、电阻R20和运算放大器U4-B；
所述电阻R16的第一端连接所述AC-DC转换电路的正输出端，所述电阻R16的第二端连接所述运算放大器U4-B的正输入端，所述运算放大器U4-B的正输入端还通过所述电阻R17接地，所述电阻R18的第一端连接所述基准设定电路的电压基准端，所述电阻R18的第二端连接所述运算放大器U4-B的负输入端，所述电阻R18的第二端还依次通过所述电容C3和所述电阻R19连接所述运算放大器U4-B的输出端，所述运算放大器U4-B的输出端连接所述电阻R20的第一端，所述电阻R20的第二端连接所述电流采样电路的输出端后还连接所述恒功率调节电路的第一输入端；
所述电阻R16的第一端为所述电压采样电路的输入端，所述电阻R18的第一端为所述电压采样电路的电压输入端，所述电阻R20的第二端为所述电压采样电路的输出端。
优选地，所恒功率调节电路包括：电容C5、电阻R27、电阻R28、光电耦合器OT1-A、运算放大器U5-B；
所述电容C5与所述电阻R27串联后，并联在所述运算放大器U5-B的负输入端和输出端之间，所述运算放大器U5-B的负输入端还连接所述电流采样电路的输出端和电压采样电路的输出端，所述运算放大器U5-B的正输入端连接所述信号处理电路的输出端，所述运算放大器U5-B的输出端通过所述电阻R28连接所述光电耦合器OT1-A的第二端，所述光电耦合器OT1-A的第一端连接VCC，所述光电耦合器OT1-A耦合到所述AC-DC转换电路的反馈端；
所述运算放大器U5-B的负输入端为所述恒功率调节电路的第一输入端，所述运算放大器U5-B的正输入端为所述恒功率调节电路的第二输入端。
本发明还提供一种LED驱动电源，包括以上所述的恒功率LED驱动电路。
 有益效果
实施本发明的恒功率LED驱动电路，具有以下有益效果：本发明可以实现自动调整输出电压和输出电流，实现恒功率输出，且输出功率与输入的电压无关，可大大提高LED驱动电源的适用领域。另外，本发明的恒功率LED驱动电路采用自动检测电压与电流的方式，自动调整输出电压和输出电压，并进行恒功率控制，以实现恒功率输出的目的，可以有效节省人工成本，同时还可以避免人为操作产生的误操作。
 附图说明
下面将结合附图及实施例对本发明作进一步说明，附图中：
图1是本发明的恒功率LED驱动电路第一实施例的结构示意图；
图2是本发明的恒功率LED驱动电路第二实施例的结构示意图；
图3是本发明实施例的恒功率LED驱动电路的电路原理图。
 本发明的最佳实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
参考图1，为本发明实施例的恒功率LED驱动电路结构示意图。如图1所示，该恒功率LED驱动电路包括：AC-DC转换电路10、基准设定电路20、电流采样电路40、电压采样电路50、信号处理电路60、以及恒功率调节电路70。其中，AC-DC转换电路10的正输出端（LED+）分别连接基准设定电路20的输入端和电压采样电路50的输入端，AC-DC转换电路10的负输出端（LED-）连接电流采样电路40的输入端；基准设定电路20的电流基准端连接信号处理电路60的输入端，基准设定电路20的电压基准端连接电压采样电路50的电压输入端；电流采样电路40的输出端与电压采样电路50的输出端连接后、再连接恒功率调节电路70的第一输入端；信号处理电路60的输出端连接恒功率调节电路70的第二输入端；恒功率调节电路70还连接AC-DC转换电路10的反馈端。
本发明实施例中，AC-DC转换电路10用于将交流电转换为直流电并将直流电输出至负载。
基准设定电路20用于产生基准信号。其中，基准设定电路20所产生的基准信号包括电流基准信号和电压基准信号，通过该基准设定电路20产生相应的电流基准信号和电压基准信号可以控制LED驱动电源的输出电压和输出电流。
电流采样电路40用于对采集AC-DC转换电路10输出的电流信号及放大处理，并将放大处理的电流信号输出至恒功率调节电路70。本发明实施例中，电流采样电路40可以对所采集的电流信号按照一定比例进行放大处理后再传送至恒功率调节电路70，由恒功率调节电路70进行相应的比较放大处理并反馈至AC-DC转换电路10，以对AC-DC转换电路10的输出电流进行调节，达到自动调节LED驱动电源的输出电流的目的。其中，AC-DC转换电路10的输出电流即为LED驱动电源的输出电流。
电压采样电路50用于采集AC-DC转换电路10输出的电压信号并将所采集的电压信号输出至恒功率调节电路70。该电压采样电路50可以采用电阻分压的方式来反馈AC-DC转换电路10输出的电压信号的电压值以及电压信号的变化情况，并将所反馈的电压值或者电压信号的变化情况传送至恒功率调节电路70，实现对AC-DC转换电路10输出的电压信号的调节，即实现对LED驱动电源的输出电压的调节，达到自动调节LED驱动电源的输出电压的目的。其中，AC-DC转换电路10的输出电压即为LED驱动电源的输出电压。
信号处理电路60用于将所接收的基准设定电路20输出的基准信号进行处理转换为直流信号，并将该直流信号发送给恒功率调节电路70。
恒功率调节电路70用于根据所接收的电流信号、电压信号、直流信号输出反馈信号至AC-DC转换电路10，以使AC-DC转换电路10保持恒功率输出。通过恒功率调节电路70输出的反馈信号至AC-DC转换电路10可以使AC-DC转换电路10根据LED驱动电源的实际输出信号（电压信号和电流信号）调节LED驱动电源的输出电流，以使LED驱动电源达到恒功率输出的目的。
参考图2，图2为本发明提供的恒功率LED驱动电路第二实施例的结构示意图。
该实施例在第一实施例的基础上，进一步还包括：调光电路30。
该调光电路30与信号处理电路60连接，用于接收和处理调光信号、并将处理后的调光信号传送至信号处理电路60。该调光电路30可以将不同的调光信号（如电阻调光信号、电压调光信号、PWM调光信号中的任意一种或多种）处理成线性变化的PWM调光信号。其中，调光信号是由外部电路提供的。
该信号处理电路60主要是将调光电路30输出的线性变化的PWM信号转换成一定比例的直流信号，并发送给恒功率调节电路70。
通过在第一实施例的基础上增加调光电路，可以使本发明的恒功率LED驱动电路根据不同的调光信号调节LED驱动电源的输出电流，以使LED驱动电源在不同的调光信号作用下仍可以实现恒功率输出。
具体的，参考图3，为本发明实施例的恒功率LED驱动电路一优选实施例的电路原理图，其中，该电路原理图为调光恒功率输出，即该恒功率可以根据不同的调光信号调节LED驱动电源的输出电流，使LED驱动电源在不同的调光信号作用下仍可以实现恒功率输出。
如图3所示，本发明实施例中，AC-DC转换电路10包括保险丝F1、共模电感LF1、整流桥BD1、电解电容CE1、二极管D2、电解电容CE2、开关MOS管Q1、电阻R4、光电耦合器OT1-B以及控制IC U1。
其具体的工作原理为：交流电AC经过保险丝F1及共模电感LF1至整流桥BD1，整流后的电压通过电解电容CE1滤波直流电压，滤波后的直流电压通过变压器按一定比例耦合至次级侧，次级经过二极管D2整流，电解电容CE2滤波直流输出电压和电流，开关MOS管Q1根据开关PWM信号控制输出电压和输出电流的大小，具体为由光电耦合器OT1-B控制控制IC U1的反馈端（FB），由控制IC U1根据反馈端的反馈信号输出PWM信号至电阻R3控制开关MOS管Q1的占空比，从而实现稳定输出电压和电流的目的，达到恒功率输出。
本发明实施例中，基准设定电路20包括：线性稳压电路201、电压产生电路202、基准信号产生电路203。
线性稳压电路201的输入端连接AC-DC转换电路10的正输出端，线性稳压电路201的输出端连接电压产生电路202的输入端，电压产生电路202的输出端连接基准信号产生电路203的输入端，基准信号产生电路203的第一输出端连接信号处理电路60的输入端，基准信号产生电路203的第二输出端连接电压采样电路50的基准电压端；线性稳压电路201的输入端为基准设定电路20的输入端，基准信号产生电路203的第一输出端为基准设定电路20的电流基准端，基准信号产生电路203的第二输出端为基准设定电路20的电压基准端。
具体的，如图3所示，线性稳压电路201包括：电阻R5、三极管Q2、稳压管ZD1、电解电容CE3。
电阻R5的第一端和三极管Q2的集电极一并连接AC-DC转换电路10的正输出端，电阻R5的第二端和三极管Q2的基极一并连接稳压管ZD1的负极，稳压管ZD1的正极与电解电容CE3的第二端一并接地，三极管Q2的发射极和电解电容CE3的第一端一并连接电压产生电路202的输入端；电阻R5的第一端和三极管Q2的集电极为线性稳压电路201的输入端，三极管Q2的发射极和电解电容CE3的第一端为线性稳压电路201的输出端。
电压产生电路202包括：电阻R6、基准稳压器U2、电阻R7、电阻R8和电容C2。
电阻R6的第一端连接线性稳压电路201的输入端，电阻R6的第二端分别连接基准稳压器U2的第三端、电阻R7的第一端和电容C2的第一端，基准稳压器U2的第二端和电阻R8的第二端、电容C2的第二端一并接地，基准稳压器U2的第一端连接电阻R7的第二端和电阻R8的第一端；电阻R6的第二端和电容C2的第一端的连接端还连接基准信号产生电路203的输入端；电阻R6的第一端为电压产生电路202的输入端，电阻R6的第二端和电容C2的第一端的连接端为电压产生电路202的输出端。
基准信号产生电路203包括：电阻R9、可调电位器VR1和电阻R10。
电阻R9的第一端连接电压产生电路202的输出端，电阻R9的第二端连接可调电位器VR1的第一端，可调电位器VR1的第二端连接电阻R10的第一端，电阻R10的第二端接地；电阻R9的第二端和可调电位器VR1的第一端的连接端还连接信号处理电路60的输入端，可调电位器VR1的第二端和电阻R10的第一端的连接端还连接电压采样电路50的基准电压端；电阻R9的第二端和可调电位器VR1的第一端的连接端为基准信号产生电路203的第一输出端，可调电位器VR1的第二端和电阻R10的第一端的连接端为基准信号产生电路203的第二输出端。
其工作原理为：输出电压通过线性稳压电路201后输出稳定电压VCC，该稳定电压VCC通过电阻R6、基准稳压器U2（TL431）、电阻R7、电阻R8和电容C2后产生稳定的基准电压，该稳定的基准电压通过电阻R9、可调电位器VR1和电阻R10输出电流基准信号（IREF）和电压基准信号（VREF）。其中，电流基准信号（IREF）和电压基准信号（VREF）是由可调电位器VR1恒等比例变化得到的，可以通过设置可调电位器VR1处于某一电位器值时，设定恒等最大输出电压和最大输出电流，从而实现恒等输出功率。
另外，该稳定电压VCC还传送至控制IC U1及LED驱动电源内部的其他电路，用于作为控制IC U1及LED驱动电源内部的其他电路的供电电压。
如图3所示，信号处理电路60包括光电耦合器OT2-B、电阻R21、电阻R22、MOS管Q3、电阻R23、电阻R24、电阻R25、电容C4、运算放大器U5-A和电阻R26；
光电耦合器OT2-B耦合至调光电路30，光电耦合器OT2-B的第三端接地，光电耦合器OT2-B的第四端连接电阻R21和电阻R22的连接节点并连接至MOS管Q3的基极，电阻R21的第一端连接VCC，电阻R22的第二端接地，MOS管Q3的漏极连接电阻R23的第二端，MOS管Q3的源极接地，电阻R23的第一端连接基准设定电路20的电流基准端，电阻R24的第一端连接电阻R23的第一端，电阻R24的第二端通过电容C4接地，电阻R24和电容C4的连接端通过电阻R25连接运算放大器U5-A的正输入端，运算放大器U5-A的负输入端与其输出端短接，运算放大器U5-A的输出端连接电阻R26的第一端，电阻R26的第二端连接恒功率调节电路70的第二输入端；电阻R23的第一端和电阻R24的第一端的连接端为信号处理电路60的输入端，电阻R26的第二端为信号处理电路60的输出端。
其工作原理为：稳定电压VCC经过电阻R21、电阻R22、光电耦合器OT2-B至MOS管Q3的基极（驱动脚），MOS管Q3的漏极接电阻R23至电流基准信号（IREF）。其中，电阻R23主要起到设定最小调光输出电流的作用。光电耦合器OT2-B接收调光电路30输出的线性调光信号（PWM信号），并将该PWM信号通过MOS管Q3后，使电阻R23的第一端上的电流基准信号（IREF）为恒定幅值的PWM电压，该恒定幅值的PWM电压通过电阻R24、电容C4滤波为直流电压，直流电压通过电阻R25至运算放大器U5-A的正输入端，U5-A实现电压跟随，输出直流电压信号并通过电阻R26至运算放大器U5-B的正输入端（即恒功率调节电路70的第二输入端）。
当然，可以理解地，在其他一些实施例中，当该恒功率LED驱动电路为不调光的恒功率输出的LED驱动电路时，信号处理电路60只包括：电阻R24、电阻R25、运算放大器U5-A、电阻R26和电容C4。
其中，电阻R24的第一端连接基准设定电路20的电流基准端，电阻R24的第二端通过电容C4接地，电阻R24和电容C4的连接端通过电阻R25连接运算放大器U5-A的正输入端，运算放大器U5-A的负输入端与其输出端短接，运算放大器U5-A的输出端连接电阻R26的第一端，电阻R26的第二端连接恒功率调节电路的第二输入端；此时，电阻R24的第一端为为信号处理电路60的输入端，电阻R26的第二端为信号处理电路60的输出端；而且，在该实施例中，电阻R24为0欧姆。
如图3所示，本发明实施例中，电流采样电路40包括：电阻R11、电阻R12、电阻R13、电阻R14、运算放大器U4-A和电阻R15。
电阻R11的第一端接地，电阻R11的第二端通过电阻R14连接运算放大器U4-A的输出端，电阻R11的第二端还连接运算放大器U4-A的负输入端；电阻R12的第一端连接AC-DC转换电路10的负输出端，电阻R12的第二端连接运算放大器U4-A的正输入端，运算放大器U4-A的正输入端还通过电阻R13接地，运算放大器U4-A的输出端连接电阻R15的第一端，电阻R15的第二端连接恒功率调节电路70的第一输入端；电阻R12的第一端为电流采样电路40的输入端，电阻R15的第二端为电流采样电路40的输出端。
其工作原理为：AC-DC转换电路10的负输出端的信号通过电阻R12、电阻R13至运算放大器U4-A的正输入端，U4-A的负输入端由电阻R11接地，U4-A的负输入端接电阻R14，从而实现采样小电流信号并通过运算放大器U4-A放大为一定比值的电压，该比值电压通过电阻R15输出至运算放大器U5-B的负输入端（即恒功率调节电路70的第一输入端）。
如图3所示，本发明实施例中，该电压采样电路50包括：电阻R16、电阻R17、电阻R18、电阻R19、电容C3、电阻R20和运算放大器U4-B。
电阻R16的第一端连接AC-DC转换电路10的正输出端，电阻R16的第二端连接运算放大器U4-B的正输入端，运算放大器U4-B的正输入端还通过电阻R17接地，电阻R18的第一端连接基准设定电路20的电压基准端，电阻R18的第二端连接运算放大器U4-B的负输入端，电阻R18的第二端还依次通过电容C3和电阻R19连接运算放大器U4-B的输出端，运算放大器U4-B的输出端连接电阻R20的第一端，电阻R20的第二端连接电流采样电路40的输出端后还连接恒功率调节电路70的第一输入端；电阻R16的第一端为电压采样电路50的输入端，电阻R18的第一端为电压采样电路50的电压输入端，电阻R20的第二端为电压采样电路50的输出端。
如图3所示，本发明实施例中，该恒功率调节电路70包括：电容C5、电阻R27、电阻R28、光电耦合器OT1-A、运算放大器U5-B。
电容C5与电阻R27串联后，并联在运算放大器U5-B的负输入端和输出端之间，运算放大器U5-B的负输入端还连接电流采样电路40的输出端和电压采样电路50的输出端，运算放大器U5-B的正输入端连接信号处理电路60的输出端，运算放大器U5-B的输出端通过电阻R28连接光电耦合器OT1-A的第二端，光电耦合器OT1-A的第一端连接VCC，光电耦合器OT1-A耦合到AC-DC转换电路10的反馈端；运算放大器U5-B的负输入端为恒功率调节电路70的第一输入端，运算放大器U5-B的正输入端为恒功率调节电路70的第二输入端。
其工作原理为：电流采样电路40输出的信号输入至运算放大器U5-B的负输入端，电压采样电路50输出的信号输入至运算放大器U5-B的负输入端；信号处理电路60输出的直流电压信号通过电阻R26输出至运算放大器U5-B的正输入端；运算放大器U5-B通过电阻R27和电容C5进行环路补偿，运算放大器U5-B的输出端通过电阻R28接至光电耦合器OT1-A，由光电耦合器OT1-A将反馈信号耦合至光电耦合器OT1-B，由光电耦合器OT1-B将反馈信号反馈至控制IC U1的反馈端（FB），由控制IC U1根据反馈端的反馈信号输出PWM信号至电阻R3控制开关MOS管Q1的占空比，从而实现稳定输出电压和电流的目的，达到恒功率输出。这里，当调光电路30接收的是PWM调光信号、电压调光信号、电阻调光信号中的任意一种时，本发明的恒功率LED驱动电路都可以稳定线性比例调节LED驱动电源的输出电压和输出电流，实现恒功率输出。
本发明的恒功率LED驱动电路使用运算放大器和传感器的纯模拟电路，可以实现自动调节输出电压和输出电流，通过运算放大器的不同去处，实现输出功率的恒定输出，而且输出功率与输入电压无关，可大大提高LED驱动电源的适用领域。同时，本发明采用自动检测输出电压与输出电流的设计，并根据输出电压与输出电流的实际变化自动实时调整输出电压与输出电流，实现恒流输出的目的，不再需要人为调节，有效节省人工成本，并能避免人为操作导致的失误。
另外，本发明的恒功率LED驱动电路还可以扩宽单个LED电源的工作范围，使其适应更宽的电压、电流范围，从而减少单个系列的机型数量，可以更为灵活地搭配灯具，减少客户的备货量。
本发明还公开了一种LED驱动电源，该LED驱动电源包括前述的恒功率LED驱动电路。通过设置上述恒功率LED驱动电路，可以使LED驱动电源实现恒功率输出且可自动调整输出电压和输出电流。
以上实施例只为说明本发明的技术构思及特点，其目的在于让熟悉此项技术的人士能够了解本发明的内容并据此实施，并不能限制本发明的保护范围。凡跟本发明权利要求范围所做的均等变化与修饰，均应属于本发明权利要求的涵盖范围。
应当理解的是，对本领域普通技术人员来说，可以根据上述说明加以改进或变换，而所有这些改进和变换都应属于本发明所附权利要求的保护范围。

Claims (10)

  1. 一种恒功率LED驱动电路，其特征在于，包括：AC-DC转换电路、基准设定电路、电流采样电路、电压采样电路、信号处理电路、以及恒功率调节电路；
    所述AC-DC转换电路的正输出端分别连接所述基准设定电路的输入端和所述电压采样电路的输入端，所述AC-DC转换电路的负输出端连接所述电流采样电路的输入端；所述基准设定电路的电流基准端连接所述信号处理电路的输入端，所述基准设定电路的电压基准端连接所述电压采样电路的电压输入端；所述电流采样电路的输出端与所述电压采样电路的输出端连接后、再连接所述恒功率调节电路的第一输入端；所述信号处理电路的输出端连接所述恒功率调节电路的第二输入端；所述恒功率调节电路还连接所述AC-DC转换电路的反馈端；
    所述AC-DC转换电路用于将交流电转换为直流电并将所述直流电输出至负载，所述基准设定电路用于产生基准信号，所述电流采样电路用于对采集所述AC-DC转换电路输出的电流信号及放大处理，并将放大处理的电流信号输出至所述恒功率调节电路；所述电压采样电路用于采集所述AC-DC转换电路输出的电压信号并将所采集的电压信号输出至所述恒功率调节电路，所述信号处理电路用于接收所述基准设定电路输出的基准信号并输出直流信号至所述恒功率调节电路；所述恒功率调节电路用于根据所接收的电流信号、电压信号、直流信号输出反馈信号至所述AC-DC转换电路，以使所述AC-DC转换电路保持恒功率输出。
  2. 根据权利要求1所述的恒功率LED驱动电路，其特征在于，还包括：
    与所述信号处理电路连接的调光电路；
    所述调光电路用于接收和处理调光信号、并将处理后的调光信号传送至所述信号处理电路。
  3. 根据权利要求1所述的恒功率LED驱动电路，其特征在于，所述基准设定电路包括：线性稳压电路、电压产生电路、基准信号产生电路；
    所述线性稳压电路的输入端连接所述AC-DC转换电路的正输出端，所述线性稳压电路的输出端连接所述电压产生电路的输入端，所述电压产生电路的输出端连接所述基准信号产生电路的输入端，所述基准信号产生电路的第一输出端连接所述信号处理电路的输入端，所述基准信号产生电路的第二输出端连接所述电压采样电路的基准电压端；
    所述线性稳压电路的输入端为所述基准设定电路的输入端，所述基准信号产生电路的第一输出端为所述基准设定电路的电流基准端，所述基准信号产生电路的第二输出端为所述基准设定电路的电压基准端。
  4. 根据权利要求3所述的恒功率LED驱动电路，其特征在于，所述线性稳压电路包括：电阻R5、三极管Q2、稳压管ZD1、电解电容CE3；
    所述电阻R5的第一端和所述三极管Q2的集电极一并连接所述AC-DC转换电路的正输出端，所述电阻R5的第二端和所述三极管Q2的基极一并连接所述稳压管ZD1的负极，所述稳压管ZD1的正极与所述电解电容CE3的第二端一并接地，所述三极管Q2的发射极和所述电解电容CE3的第一端一并连接所述电压产生电路的输入端；
    所述电阻R5的第一端和所述三极管Q2的集电极为所述线性稳压电路的输入端，所述三极管Q2的发射极和所述电解电容CE3的第一端为所述线性稳压电路的输出端。
  5. 根据权利要求3所述的恒功率LED驱动电路，其特征在于，所述电压产生电路包括：电阻R6、基准稳压器U2、电阻R7、电阻R8和电容C2；
    所述电阻R6的第一端连接所述线性稳压电路的输入端，所述电阻R6的第二端分别连接所述基准稳压器U2的第三端、所述电阻R7的第一端和所述电容C2的第一端，所述基准稳压器U2的第二端和所述电阻R8的第二端、所述电容C2的第二端一并接地，所述基准稳压器U2的第一端连接所述电阻R7的第二端和所述电阻R8的第一端；所述电阻R6的第二端和所述电容C2的第一端的连接端还连接所述基准信号产生电路的输入端；
    所述电阻R6的第一端为所述电压产生电路的输入端，所述电阻R6的第二端和所述电容C2的第一端的连接端为所述电压产生电路的输出端。
  6. 根据权利要求3所述的恒功率LED驱动电路，其特征在于，所述基准信号产生电路包括：电阻R9、可调电位器VR1和电阻R10；
    所述电阻R9的第一端连接所述电压产生电路的输出端，所述电阻R9的第二端连接所述可调电位器VR1的第一端，所述可调电位器VR1的第二端连接所述电阻R10的第一端，所述电阻R10的第二端接地；所述电阻R9的第二端和所述可调电位器VR1的第一端的连接端还连接所述信号处理电路的输入端，所述可调电位器VR1的第二端和所述电阻R10的第一端的连接端还连接所述电压采样电路的基准电压端；
    所述电阻R9的第二端和所述可调电位器VR1的第一端的连接端为所述基准信号产生电路的第一输出端，所述可调电位器VR1的第二端和所述电阻R10的第一端的连接端为所述基准信号产生电路的第二输出端。
  7. 根据权利要求2所述的恒功率LED驱动电路，其特征在于，所述信号处理电路包括：电阻R24、电阻R25、运算放大器U5-A、电阻R26和电容C4；
    所述电阻R24的第一端连接所述基准设定电路的电流基准端，所述电阻R24的第二端通过所述电容C4接地，所述电阻R24和所述电容C4的连接端通过所述电阻R25连接所述运算放大器U5-A的正输入端，所述运算放大器U5-A的负输入端与其输出端短接，所述运算放大器U5-A的输出端连接所述电阻R26的第一端，所述电阻R26的第二端连接所述恒功率调节电路的第二输入端；此时，所述电阻R24的第一端为为所述信号处理电路的输入端，所述电阻R26的第二端为所述信号处理电路的输出端；
    或者，所述信号处理电路包括：光电耦合器OT2-B、电阻R21、电阻R22、MOS管Q3、电阻R23、电阻R24、电阻R25、电阻R24、电阻R25、运算放大器U5-A、电阻R26和电容C4；
    光电耦合器OT2-B耦合至调光电路，光电耦合器OT2-B的第三端接地，光电耦合器OT2-B的第四端连接所述电阻R21和所述电阻R22的连接节点并连接至所述MOS管Q3的基极，所述电阻R21的第一端连接VCC，所述电阻R22的第二端接地，所述MOS管Q3的漏极连接所述电阻R23的第二端，所述MOS管Q3的源极接地，所述电阻R23的第一端连接所述基准设定电路的电流基准端，所述电阻R24的第一端连接所述电阻R23的第一端，所述电阻R24的第二端通过所述电容C4接地，所述电阻R24和所述电容C4的连接端通过所述电阻R25连接所述运算放大器U5-A的正输入端，所述运算放大器U5-A的负输入端与其输出端短接，所述运算放大器U5-A的输出端连接所述电阻R26的第一端，所述电阻R26的第二端连接所述恒功率调节电路的第二输入端；此时，所述电阻R23的第一端和所述电阻R24的第一端的连接端为所述信号处理电路的输入端，所述电阻R26的第二端为所述信号处理电路的输出端。
  8. 根据权利要求1所述的恒功率LED驱动电路，其特征在于，电流采样电路包括：电阻R11、电阻R12、电阻R13、电阻R14、运算放大器U4-A和电阻R15；
    所述电阻R11的第一端接地，所述电阻R11的第二端通过所述电阻R14连接所述运算放大器U4-A的输出端，所述电阻R11的第二端还连接所述运算放大器U4-A的负输入端；所述电阻R12的第一端连接所述AC-DC转换电路的负输出端，所述电阻R12的第二端连接所述运算放大器U4-A的正输入端，所述运算放大器U4-A的正输入端还通过所述电阻R13接地，所述运算放大器U4-A的输出端连接所述电阻R15的第一端，所述电阻R15的第二端连接所述恒功率调节电路的第一输入端；
    所述电阻R12的第一端为所述电流采样电路的输入端，所述电阻R15的第二端为所述电流采样电路的输出端；
    所述电压采样电路包括：电阻R16、电阻R17、电阻R18、电阻R19、电容C3、电阻R20和运算放大器U4-B；
    所述电阻R16的第一端连接所述AC-DC转换电路的正输出端，所述电阻R16的第二端连接所述运算放大器U4-B的正输入端，所述运算放大器U4-B的正输入端还通过所述电阻R17接地，所述电阻R18的第一端连接所述基准设定电路的电压基准端，所述电阻R18的第二端连接所述运算放大器U4-B的负输入端，所述电阻R18的第二端还依次通过所述电容C3和所述电阻R19连接所述运算放大器U4-B的输出端，所述运算放大器U4-B的输出端连接所述电阻R20的第一端，所述电阻R20的第二端连接所述电流采样电路的输出端后还连接所述恒功率调节电路的第一输入端；
    所述电阻R16的第一端为所述电压采样电路的输入端，所述电阻R18的第一端为所述电压采样电路的电压输入端，所述电阻R20的第二端为所述电压采样电路的输出端。
  9. 根据权利要求1所述的恒功率LED驱动电路，其特征在于，所恒功率调节电路包括：电容C5、电阻R27、电阻R28、光电耦合器OT1-A、运算放大器U5-B；
    所述电容C5与所述电阻R27串联后，并联在所述运算放大器U5-B的负输入端和输出端之间，所述运算放大器U5-B的负输入端还连接所述电流采样电路的输出端和电压采样电路的输出端，所述运算放大器U5-B的正输入端连接所述信号处理电路的输出端，所述运算放大器U5-B的输出端通过所述电阻R28连接所述光电耦合器OT1-A的第二端，所述光电耦合器OT1-A的第一端连接VCC，所述光电耦合器OT1-A耦合到所述AC-DC转换电路的反馈端；
    所述运算放大器U5-B的负输入端为所述恒功率调节电路的第一输入端，所述运算放大器U5-B的正输入端为所述恒功率调节电路的第二输入端。
  10. 一种LED驱动电源，其特征在于，包括权利要求1-9任一项所述的恒功率LED驱动电路。
PCT/CN2019/080579 2018-09-13 2019-03-29 恒功率led驱动电路及led驱动电源 WO2020052223A1 (zh)

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