A PWM dimming flicker-free LED driver power supply synchronous control circuit

Abstract

This utility model discloses a PWM dimming flicker-free LED driver power supply synchronous control circuit, including a power supply synchronous control circuit. The power supply synchronous control circuit includes a 110VDC input, several control units, and a slave microcontroller. One end of the 110VDC input is connected to one end of each of the several control units, and the other end of each of the several control units is connected to one end of the slave microcontroller. Each of the several control units includes an input filter, a Buck converter, a constant current control unit, an LED load, and a dimming detection circuit unit. This utility model's PWM dimming flicker-free LED driver power supply synchronous control circuit enables the driver circuit to achieve unified dimming control and real-time monitoring of LED load current, reducing the voltage and current distribution problems caused by inconsistent LED characteristics. It can basically achieve uniform brightness, and the converter can meet general power supply requirements. It realizes digital monitoring and parameter memory functions, and has high practicality.

Description

Technical Field

[0001] This utility model relates to the field of power supply synchronization control circuit technology, specifically a PWM dimming flicker-free LED driver power supply synchronization control circuit. Background Technology

[0002] AC LED driver power supplies often adopt a two-stage structure, including a power factor correction unit and a DC-DC conversion unit, which respectively realize the functions of power factor correction and constant current drive. High-power LED light sources are composed of multiple LED beads arranged in a certain way. Due to the limitations of the manufacturing process, the characteristics of the LED beads inevitably have certain differences. The power synchronization control circuit is used to control the output voltage waveform of multiple power modules to be the same and in phase. Its implementation principle is to control the PWM waveform of the power modules through the synchronization signal, so that the output voltage waveform of multiple power modules is the same and in phase, avoiding power supply noise and electromagnetic interference caused by output voltage phase differences.

[0003] However, traditional power synchronization control circuits have the following drawbacks: Currently, the power synchronization control circuits on the market use a single-channel constant current output LED driver power supply, which can cause uneven voltage and current distribution of the LED beads, resulting in uneven light emission. Utility Model Content

[0004] The purpose of this invention is to provide a PWM dimming flicker-free LED driver power supply synchronous control circuit to solve the problem mentioned in the background art, which states that the current power supply synchronous control circuits on the market use a single constant current output LED driver power supply method, which causes uneven voltage and current distribution of the LED beads, resulting in uneven light emission brightness.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a PWM dimming flicker-free LED driver power supply synchronous control circuit, comprising a power supply synchronous control circuit, wherein the power supply synchronous control circuit includes a 110VDC input, several control units, and a slave microcontroller. One end of the 110VDC input is connected to one end of each of the several control units, and the other end of each of the several control units is connected to one end of the slave microcontroller. Each of the several control units includes an input filter, a Buck converter, a constant current control unit, an LED load, and a dimming detection circuit unit. One end of the input filter is connected to one end of the Buck converter, the other end of the Buck converter is connected to one end of the constant current control unit, the other end of the constant current control unit is connected to one end of the LED load, one side of the constant current control unit is connected to one end of the dimming detection circuit unit, and the other side of the constant current control unit and the other end of the dimming detection circuit unit are both connected to the end of the Buck converter directly opposite it.

[0006] Preferably, one side of the dimming detection circuit unit is connected to the microcontroller, and the other end of the input filter is connected to a 110VDC input.

[0007] Preferably, the dimming detection circuit unit includes resistors R1, R2, and R3, operational amplifier 1, operational amplifier 2, resistors R4, R5, and R6. The negative terminal of operational amplifier 1 is connected to one end of resistor R3, the positive terminal of operational amplifier 1 is connected to one end of resistor R1 and one end of resistor R2, the other end of resistor R3 is connected to one end of resistor R4, the other end of resistor R4 is connected to the positive terminal of operational amplifier 2, the negative terminal of operational amplifier 2 is connected to one end of resistor R5 and one end of resistor R6, and the other ends of resistors R2 and R5 are both grounded.

[0008] Preferably, the dimming detection circuit unit includes resistors R1, R2, R3, R4, R5, and Rs, operational amplifier 1, and operational amplifier 2. The positive terminal of operational amplifier 1 is connected to one end of R1, the other end of resistor R1 is connected to one end of resistor Rs, the negative terminal of operational amplifier 1 is connected to one end of resistor R2, the other end of resistor R2 is connected to one end of resistor R3, the other end of resistor R3 is connected to the positive terminal of operational amplifier 2, the negative terminal of operational amplifier 2 is connected to one end of resistor R4 and one end of resistor R5, and the other ends of resistors R4 and Rs are both grounded.

[0009] Preferably, the constant current control unit includes a 485 interface, a main microcontroller, a power supply module, an LCD screen, and a dimming knob. One end of the main microcontroller is connected to one end of the 485 interface, and the main microcontroller is connected to one end of the LCD screen and one end of the dimming knob. One side of the 485 interface and one side of the main microcontroller are both connected to the power supply module.

[0010] Preferably, the input filter includes an integrated circuit UIB, an electronic resistor R8, a resistor R7, a diode D5, a MOSFET Q1, and a capacitor C9. Pin 3 of the integrated circuit UIB is connected to one end of the resistor R8. Pins 6 and 7 of the integrated circuit UIB are connected to one end of the resistor R7 and one end of the diode D5, respectively. The other end of the resistor R7 is connected to one end of the MOSFET Q1. The other end of the MOSFET Q1 is connected to the other end of the diode D5. Pin 8 of the integrated circuit UIB is connected to one end of the capacitor C9. The other end of the resistor R8 is grounded.

[0011] Compared with the prior art, the beneficial effects of this utility model are: it enables unified dimming control and real-time monitoring of LED load current for the driving circuit, reduces the voltage and current distribution problem caused by inconsistent characteristics of LED beads, and can basically achieve uniform brightness. The converter can meet general power supply requirements, realize digital monitoring and parameter memory functions, and has high practicality. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the architecture of this utility model; Figure 2 This is a schematic diagram of the architecture of the control unit of this utility model; Figure 3 This is one of the circuit diagrams of the dimming detection circuit unit of this utility model; Figure 4 This is the second circuit diagram of the dimming detection circuit unit of this utility model; Figure 5 This is a schematic diagram of the architecture of the constant current control unit of this utility model; Figure 6 This is the circuit diagram of the input filter of this utility model. Detailed Implementation

[0013] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0014] Please see Figure 1-6 This utility model provides a PWM dimming flicker-free LED driver power supply synchronization control circuit, including a power supply synchronization control circuit. The power supply synchronization control circuit includes a 110VDC input, several control units, and a slave microcontroller. One end of the 110VDC input is connected to one end of each of the several control units, and the other end of each of the several control units is connected to one end of the slave microcontroller. Each of the several control units includes an input filter, a Buck converter, a constant current control unit, an LED load, and a dimming detection circuit unit. One end of the input filter is connected to one end of the Buck converter, and the other end of the Buck converter is connected to one end of the constant current control unit. The other end of the constant current control unit is connected to one end of the dimming detection circuit unit, and the other end of both the constant current control unit and the dimming detection circuit unit are connected to the end of the Buck converter directly opposite it.

[0015] One side of the dimming detection circuit unit is connected to the microcontroller, and the other end of the input filter is connected to the 110VDC input.

[0016] The dimming detection circuit unit includes resistors R1, R2, R3, operational amplifier 1, operational amplifier 2, resistors R4, R5, and R6. The negative terminal of operational amplifier 1 is connected to one end of resistor R3, and the positive terminal of operational amplifier 1 is connected to one end of resistor R1 and one end of resistor R2. The other end of resistor R3 is connected to one end of resistor R4, and the other end of resistor R4 is connected to the positive terminal of operational amplifier 2. The negative terminal of operational amplifier 2 is connected to one end of resistor R5 and one end of resistor R6. The other ends of resistors R2 and R5 are both grounded.

[0017] The dimming detection circuit unit includes resistors R1, R2, R3, R4, R5, and Rs, as well as operational amplifiers 1 and 2. The positive terminal of operational amplifier 1 is connected to one end of R1, the other end of resistor R1 is connected to one end of resistor Rs, the negative terminal of operational amplifier 1 is connected to one end of resistor R2, the other end of resistor R2 is connected to one end of resistor R3, the other end of resistor R3 is connected to the positive terminal of operational amplifier 2, and the negative terminal of operational amplifier 2 is connected to one end of resistor R4 and one end of resistor R5. The other ends of resistors R4 and Rs are both grounded.

[0018] The constant current control unit includes a 485 interface, a main microcontroller, a power supply module, an LCD screen, and a dimming knob. One end of the main microcontroller is connected to one end of the 485 interface. The main microcontroller is also connected to one end of the LCD screen and one end of the dimming knob. Both one side of the 485 interface and one side of the main microcontroller are connected to the power supply module.

[0019] The input filter includes an integrated circuit UIB, an electronic resistor R8, a resistor R7, a diode D5, a MOSFET Q1, and a capacitor C9. Pin 3 of the integrated circuit UIB is connected to one end of the resistor R8. Pins 6 and 7 of the integrated circuit UIB are connected to one end of the resistor R7 and one end of the diode D5, respectively. The other end of the resistor R7 is connected to one end of the MOSFET Q1. The other end of the MOSFET Q1 is connected to the other end of the diode D5. Pin 8 of the integrated circuit UIB is connected to one end of the capacitor C9. The other end of the resistor R8 is grounded.

[0020] In this embodiment, a common and cost-effective dual operational amplifier, the LM358, is selected to detect the input voltage and output current. Since the input voltage and output current are set to 110VDC and 0.7A respectively, and the input voltage of the operational amplifier cannot exceed the maximum supply voltage of 30V, the operational amplifier cannot be directly used to acquire the required values. The detection circuit unit design is shown in Figure 4. The LM358 can be powered by a single or dual power supply. Using a method where one end is powered by a positive power supply and the other end is grounded, the input voltage is divided by resistors R1 and R2 and input to the positive terminal of operational amplifier 1, forming a voltage follower. The output voltage is then output from the negative terminal to the positive terminal of operational amplifier 2. The sampled voltage value is then amplified by resistors R5 and R6 and output to the microcontroller. The output current is converted into a voltage value by the sampling resistor Rs and input to the operational amplifier. The sampled current value is obtained in the same way and input to the microcontroller. The main microcontroller is the ATmega16 from Atmel, and the slave microcontroller is the ATmega48 from Atmel. Both have up to eight 10-bit ADC channels and six PWM channels, fulfilling the functions of dimming and sampling voltage and current in the drive circuit. Adjusting the dimming knob inputs the analog dimming signal to the main microcontroller. The main microcontroller internally converts the analog signal into a digital signal and sends it to the slave microcontroller via a RS-485 interface. The slave microcontroller, through software programming, converts the digital signal sent by the main microcontroller into a PWM signal and sends it to the PWMD pin of the HV9910B driver chip to control the driver circuit for dimming. The slave microcontroller receives the sampled values ​​from the voltage and current detection unit, internally converts the analog value into a digital signal, and sends it to the main microcontroller via the RS-485 interface. This includes the input voltage value of the drive circuit and the output current values ​​of the three channels. Through software programming, the voltage and current digital signals are converted into actual values ​​and displayed on the LCD screen for monitoring. To reduce noise signal reception and avoid parasitic oscillations... Typically, a resistor needs to be connected in series with the gate of a MOSFET. To prevent the gate from being damaged by excessive gate-source voltage, a clamping diode needs to be connected in parallel between the gate and source to limit the gate drive voltage from exceeding its maximum value.

[0021] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A PWM dimming strobe-free LED driving power supply synchronous control circuit, comprising a power supply synchronous control circuit, characterized in that: The power synchronization control circuit includes a 110VDC input, several control units, and a slave microcontroller. One end of the 110VDC input is connected to one end of each of the several control units, and the other end of each of the control units is connected to one end of the slave microcontroller. Each control unit includes an input filter, a Buck converter, a constant current control unit, an LED load, and a dimming detection circuit unit. One end of the input filter is connected to one end of the Buck converter, and the other end of the Buck converter is connected to one end of the constant current control unit. The other end of the constant current control unit is connected to one end of the dimming detection circuit unit, and the other end of both the constant current control unit and the dimming detection circuit unit are connected to the end of the Buck converter directly opposite it.

2. The PWM dimming without stroboscopic LED driving power supply synchronous control circuit according to claim 1, characterized in that: One side of the dimming detection circuit unit is connected to the microcontroller, and the other end of the input filter is connected to the 110VDC input.

3. The PWM dimming without stroboscopic LED driving power supply synchronous control circuit according to claim 1, characterized in that: The dimming detection circuit unit includes resistors R1, R2, and R3, operational amplifier 1, operational amplifier 2, resistors R4, R5, and R6. The negative terminal of operational amplifier 1 is connected to one end of resistor R3, and the positive terminal of operational amplifier 1 is connected to one end of resistor R1 and one end of resistor R2. The other end of resistor R3 is connected to one end of resistor R4, and the other end of resistor R4 is connected to the positive terminal of operational amplifier 2. The negative terminal of operational amplifier 2 is connected to one end of resistor R5 and one end of resistor R6. The other ends of resistors R2 and R5 are both grounded.

4. The PWM dimming without stroboscopic LED driving power supply synchronous control circuit according to claim 1, characterized in that: The dimming detection circuit unit includes resistors R1, R2, R3, R4, R5, and Rs, operational amplifier 1, and operational amplifier 2. The positive terminal of operational amplifier 1 is connected to one end of R1, the other end of resistor R1 is connected to one end of resistor Rs, the negative terminal of operational amplifier 1 is connected to one end of resistor R2, the other end of resistor R2 is connected to one end of resistor R3, the other end of resistor R3 is connected to the positive terminal of operational amplifier 2, and the negative terminal of operational amplifier 2 is connected to one end of resistor R4 and one end of resistor R5. The other ends of resistors R4 and Rs are both grounded.

5. The PWM dimming without stroboscopic LED driving power supply synchronous control circuit according to claim 1, characterized in that: The constant current control unit includes a 485 interface, a main microcontroller, a power supply module, an LCD screen, and a dimming knob. One end of the main microcontroller is connected to one end of the 485 interface. The main microcontroller is also connected to one end of the LCD screen and one end of the dimming knob. Both one side of the 485 interface and one side of the main microcontroller are connected to the power supply module.

6. The PWM dimming flicker-free LED driver power supply synchronous control circuit according to claim 1, characterized in that: The input filter includes an integrated circuit UIB, an electronic resistor R8, a resistor R7, a diode D5, a MOSFET Q1, and a capacitor C9. Pin 3 of the integrated circuit UIB is connected to one end of the resistor R8. Pins 6 and 7 of the integrated circuit UIB are connected to one end of the resistor R7 and one end of the diode D5, respectively. The other end of the resistor R7 is connected to one end of the MOSFET Q1. The other end of the MOSFET Q1 is connected to the other end of the diode D5. Pin 8 of the integrated circuit UIB is connected to one end of the capacitor C9. The other end of the resistor R8 is grounded.

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