CN104754840A - Novel LED driving power supply - Google Patents

Abstract

The invention discloses a novel LED driving power supply which comprises an EMI (electro-magnetic interference) filtering unit, a rectifier filter unit, a power factor correction unit, a flyback conversion unit, a constant-flow pressure limiting feedback unit, a first voltage reduction unit, a second voltage reduction unit, an LED load unit, an output voltage acquisition unit, an E2PROOM unit, a clock circuit unit, a temperature acquisition unit, an alarm module unit, a liquid crystal display unit, a 232 serial port unit and a single-chip controller unit. The novel LED driving power supply has the advantages of high power factor, high power supply efficiency, low cost, high intelligent degree and high interference rejection.

Description

A New Type of LED Driving Power Supply

technical field

The invention relates to an LED driving power supply, which belongs to the technical field of electronics.

Background technique

LED (Light Emitting Diode) lighting is also called light-emitting diode lighting. Compared with traditional incandescent lamps, fluorescent lamps and other light sources, LED light sources have the advantages of energy saving, environmental protection, low power consumption, and long life. They have become the fourth generation of green light sources. Most of the traditional light sources such as incandescent lamps can be directly powered by 220V AC. Since LEDs have the characteristics of forward voltage conduction and reverse voltage cut-off, in order to drive LED loads to work normally, LED drive power is usually required to convert 220V AC power into specific sized DC power supply.

The performance of LED driving power will directly affect the performance of LED. With the improvement of the quality requirements of LED light source, the design of LED driving power becomes more and more complicated. At the same time, in order to meet the lighting needs in different time periods and the secondary Sub-energy saving, LED dimming technology is widely used in the design of LED drive power supply. At present, the mainstream dimming technologies include: thyristor dimming, analog dimming, PWM dimming; thyristor dimming is mainly used in incandescent lamps and The principle of dimming light sources such as halogen lamps is to change the effective value by cutting the AC sine wave. Since the LED is not a pure resistive load, the thyristor dimming technology is not suitable for LED dimming; analog dimming is achieved by changing The current in the LED load realizes the adjustment of the LED brightness, but the analog dimming will increase the energy consumption of the whole system; the PWM dimming technology uses the change of the duty cycle to realize the change of the average value of the LED load current, thereby realizing the adjustment of the LED brightness, PWM Dimming technology has high precision and is widely used. Traditional LED drive power supplies mostly use dedicated dimming chips to perform PWM dimming on LED loads, but the dimming chip has a single function and is not cost-effective; Detect the running status, and cannot save the relevant running information of the drive power supply. When the driving power supply fails unexpectedly, it cannot alarm and stop operation to protect the LED load. The above problems have a certain impact on the life and reliability of the driving power supply, and restrict the further development of the LED driving power supply.

Contents of the invention

The present invention mainly aims at the disadvantages of the traditional LED drive power supply, such as the low degree of intelligence, the inability to monitor the LED load working state in real time, and the complex realization of the LED dimming function, etc., and designs a new type of LED drive power supply; the new LED drive power supply designed by the present invention has EMI filtering The device unit increases the anti-interference ability of the AC power grid, and at the same time reduces the impact of the driving power on the power grid; the new LED driving power designed in the present invention has a power factor correction unit, and the power factor correction unit adopts a mature active power factor Correction technology, the power factor can reach more than 0.9, making the LED drive power more green and environmentally friendly; the new LED drive power designed in the present invention uses a flyback (FLY BACK) conversion circuit as the main circuit, and the high-frequency transformer serves as isolation protection The role of the constant current and voltage limiting unit as a feedback loop, the constant current and voltage limiting unit is composed of operational amplifiers, three-terminal voltage regulators, linear optocouplers and other components, the constant current and voltage limiting unit makes the output voltage of the flyback conversion more stable, The anti-interference ability is stronger; the new LED drive power designed by the present invention has one main output to supply power to the LED load, and the other output to supply power to modules such as single-chip microcomputers; the new LED drive power designed by the present invention has an external clock unit, and the external clock unit Provide precise time parameter information for the driving power supply; the novel LED driving power supply designed by the present invention has an external E ² PROOM storage unit, and the single-chip microcomputer stores the operating temperature, output voltage and time information of the LED load in the external storage unit; The new LED drive power designed has a working environment temperature acquisition unit and an LED load output voltage acquisition unit; the new LED drive power designed by the present invention has a 12864 liquid crystal display unit, and the 12864 liquid crystal displays information such as time, temperature and load output voltage in real time; The new LED drive power supply designed by the invention has a key unit, which can realize the human-computer interaction function through the key unit and 12864 liquid crystal display unit. The key module can set information such as the temperature alarm value of the LED drive power supply working environment, and can also realize different duty of the single-chip microcomputer. Compared with the output of the PWM waveform, the brightness of the LED load can be adjusted; the new LED drive power designed by the present invention has a 232 serial port unit, and the entry of the single-chip program can be realized through the 232 serial port unit, and the drive power stored in the external E ² PROOM can also be read related information.

According to the technical solution provided by the present invention, the new type of LED drive power supply mainly includes: EMI filter unit, rectification filter unit, power factor correction unit, flyback conversion unit, constant current limiting voltage feedback unit, step-down 1 unit , Buck 2 unit, LED load unit, output voltage acquisition unit, E ² PROOM unit, clock circuit unit, temperature acquisition unit, alarm module unit, liquid crystal display unit, 232 serial port unit, single-chip controller unit; the 220V AC power supply After the EMI filter unit and the rectification filter unit, it is connected between the power factor correction unit, the power factor correction unit is connected to the flyback conversion unit, and the secondary rectification terminal of the flyback conversion is connected to the input terminal of the step-down 1 unit after passing through the relay , the secondary rectification terminal of the flyback conversion is directly connected to the input terminal of the buck 2 unit, the buck 1 unit provides the normal working voltage for the LED load, and the buck 1 unit provides +5V DC voltage for the microcontroller and its peripheral circuits; the LED The output voltage and real-time temperature of the load are collected by the voltage acquisition module unit and the temperature acquisition unit respectively, and sent to the 12864 liquid crystal display unit controlled by the single-chip microcomputer for synchronization after the internal A/D conversion of the single-chip microcomputer and the real-time and accurate clock information generated by the clock circuit At the same time, the MCU also sends this information to the external E ² PROOM memory for storage; when the LED load operating temperature or output voltage value is abnormal, the MCU realizes the alarm function through the alarm unit to remind the staff to come for inspection and maintenance, and at the same time, through the MCU control The relay module can disconnect the LED load circuit to achieve the purpose of protecting the LED load; the key unit can flexibly set the upper and lower limits of the LED load output voltage and the alarm value of the working temperature through the internal program of the single-chip microcomputer, and the key unit can also be realized through the single-chip microcomputer PWM waveform output, PWM waveforms with different duty ratios can realize the adjustment of LED load brightness.

The EMI filter unit is composed of safety capacitors and common mode inductors. The input end of the EMI filter is connected to a 220V AC power supply. The EMI filter can not only effectively filter out surges and peak voltages of the AC power grid, but also prevent The noise generated by the drive power pollutes the power grid.

The rectification and filtering unit is composed of a rectification bridge and a filter capacitor. The rectification bridge converts the AC voltage into a DC voltage, and the filter capacitor further filters out high-frequency noise.

The power factor correction unit adopts the active power factor correction chip L6561 working in the critical conduction mode, so that the input current of the LED drive power supply is approximately sinusoidal, and the power factor value of the LED drive power supply is improved.

The flyback conversion unit includes an isolation transformer and a constant current and voltage limiting feedback unit. The isolation transformer has the advantages of safety, reliability, and high conversion efficiency. The constant current and voltage limiting feedback unit makes the output voltage and current of the flyback conversion more stable and has better anti-interference ability powerful.

The step-down unit is divided into a step-down 1 unit and a step-down 2 unit; the step-down unit 1 supplies power to the LED load, and the step-down unit 2 supplies power to units such as a single-chip controller, a clock circuit, and an external collector.

The single-chip microcomputer unit adopts the STC12C5A60S2 chip of STC Company. The STC12C5A60S2 chip is an enhanced type 51 single-chip microcomputer chip with fast operation speed, internal integration of A/D analog-to-digital conversion function, and low power consumption. It also has low cost and is easy to develop. Rich resources and other advantages.

The temperature acquisition unit adopts DS18B20 temperature collector. DS18B20 is small in size and strong in anti-interference ability. The detection temperature range is from -55°C to 125°C, and the accuracy can reach ±0.5°C. Only one wire is required for two-way communication.

The external clock unit adopts DS1302 clock chip. DS1302 can provide accurate clock information and has leap year compensation function. can also continue to work.

The external storage unit adopts the E ² PROOM storage chip M24C02BN6, and the external storage unit is used to store the real-time clock, the temperature value of the LED load working environment and the output voltage value of the LED load ^. The controller is connected, the number of rewritable times can reach one million times, and the data retention time exceeds 40 years.

The single-chip microcomputer module sends the collected working environment temperature of the LED load and the output voltage of the LED load to the 12864 liquid crystal display module for display after the internal A/D conversion of the single-chip microcomputer and the external clock information, and also transmits these information to the E ² PROOM External memory for storage backup.

The button unit can respectively set the upper and lower limit values of the LED working environment temperature and the LED load voltage alarm through the internal program of the single-chip microcomputer; it can also change the duty cycle of the PWM waveform output by the single-chip microcomputer by pressing the button, so as to realize the dimming of the LED load.

The alarm unit adopts a buzzer alarm module. When the LED load voltage or the temperature value of the working environment is abnormal, the single-chip controller controls the buzzer to send an alarm to remind the staff to come for inspection and maintenance. Break the LED load circuit to protect the LED load from damage.

The beneficial effects of the present invention are:

(1) In the new LED drive power supply, the external clock unit provides accurate clock information for the entire system.

(2) Said a new type of LED drive power supply, the 12864 liquid crystal displays information such as the running time of the drive power supply, ambient temperature and LED load output voltage in real time.

(3) In the novel LED drive power supply, the single-chip controller controls the external storage unit to store the time when the drive power supply is running, the ambient temperature and the load output voltage information are backed up and stored.

(4) The novel LED drive power supply monitors the temperature of the LED working environment and the output voltage of the load in real time. When an abnormality occurs, the single-chip microcomputer automatically takes protective measures to cut off the LED circuit, and the buzzer sends out an alarm.

(5) The new type of LED drive power supply can set the upper and lower limit values of the alarm through the button module, and can also perform PWM dimming on the LED load.

(6) The new type of LED drive power supply can read the stored information in the external E ² PROOM memory through the 232 serial port unit, and can analyze the working state of the drive power supply.

Description of drawings

Figure 1 The overall structural block diagram of the new LED drive power supply

Figure 2 The main circuit diagram of the new LED drive power supply

Figure 3 Schematic diagram of external clock unit and external E ² PROOM storage unit

Figure 4 Circuit Diagram of Liquid Crystal Display Unit

Figure 5 Buzzer alarm unit circuit diagram

Figure 6 key unit circuit diagram

Figure 7232 serial port unit circuit diagram

Figure 8 Circuit Diagram of Temperature Acquisition Unit

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1, the circuit of the present invention includes: EMI filter unit, rectification filter unit, power factor correction unit, flyback conversion unit, constant current and voltage limiting loop unit, step-down 1 unit, step-down 2 unit, Single-chip controller module, clock circuit unit, E ² PROOM memory unit, liquid crystal display unit, 232 serial port unit, temperature acquisition unit, output voltage acquisition unit, key unit; the input end of the EMI filter unit is connected to 220V AC power supply, EMI The output end of the rectification filter unit is connected to the rectification and filtering unit; after the rectification and filtering unit rectifies and filters the AC voltage, the output end is connected to the power factor correction unit to complete the power factor correction; the output end of the power factor correction is connected to the step-down 1 unit, step-down 2 unit, the step-down 1 unit supplies power to the LED load, and the step-down 2 unit supplies power to the MCU controller unit and the clock circuit; the MCU controller unit is connected to the E ² PROOM memory unit, the clock circuit unit, the alarm module unit, and the liquid crystal display unit. , 232 serial port unit, temperature acquisition unit, button unit, etc.; the clock circuit unit provides accurate time information for the system, the temperature acquisition unit collects the temperature of the LED load in real time, and the output voltage acquisition unit collects the output voltage of the LED load; the single-chip controller unit will temperature, the output voltage is converted by the internal A/D conversion circuit and sent to the LCD unit for display together with the clock information, and at the same time, the information is also sent to the E ² PROOM memory for storage operation; when the driving power supply is abnormal and the LED load temperature is too high When the output voltage is high or the output voltage is abnormal, the single-chip microcomputer controls the relay unit to disconnect the LED load circuit to realize the protection function, and at the same time, the alarm module unit alarms; through the key unit and the internal program of the single-chip microcomputer, the single-chip microcomputer can be controlled to output PWM waveforms with different duty ratios to realize LED dimming , It is also possible to set the upper and lower limits of the alarm under abnormal conditions; through the 232 serial port unit, the entry of the single-chip program and the reading of the relevant information of the LED drive power in the external E ² PROOM are realized.

As shown in Figure 2, in the main circuit of the driving power supply, 220V AC power is input to the main circuit through the live wire (L) and the neutral wire (N). The EMI filter unit is composed of fuse FU, safety capacitors CX1, CX2, CY1, Composed of CY2 and common mode inductors L1 and L2; the fuse FU is connected in series to the live line L, the capacitor CX1 is connected across the live line L and the neutral line N, the inductor L1 is connected in series to the live line L, and the inductor L2 is connected in series to the neutral line N Above, CX2 is connected across the live line L and the neutral line N, CY1 is connected between the live line L and the ground (GND1), and the capacitor CY2 is connected between the neutral line N and the ground (GND1). The 220V AC voltage source is connected to the rectification and filtering unit after passing through the EMI filter. The rectification and filtering circuit is composed of the integrated rectification bridge D25SB80 and the filter capacitor C1. , the capacitor C1 is connected between the positive output (pin 2) and the negative output (pin 4) of the rectifier bridge, and the negative output is grounded (GND1). One end of the current limiting resistor R1 is connected to the positive output end of the rectifier bridge, and the other end is connected to pin 8 of the L6561. One end of resistor R3 is connected to the positive output end of the rectifier bridge, the other end is connected in series with resistor R4, the other end of R4 is connected to the ground (GND1), the two ends of R4 are connected in parallel with capacitor C2, resistors R3 and R4 form a voltage acquisition circuit, capacitor C2 acts as The role of sampling voltage filtering. The No. 7 pin of L6561 is connected to the gate of MOS tube MOS1 after being connected in series with resistor R7, and the No. 4 pin of L6561 is first connected to the source of MOS1, and then connected in series with resistor R8 and then connected to the ground (GND1). The high-frequency transformer T1 is composed of primary windings N1, N3 and secondary winding N2; the opposite end of N1 is connected to the positive output end, the end of the same name is connected to the drain of MOS1, and the anode of the Zener diode D1 is connected to the opposite end of N1 , the cathode of D1 is connected to the cathode of diode D2, the anode of D2 is connected to the terminal of the same name of N1, and the resistor R11 and capacitor C4 are respectively connected in parallel between the anode and cathode of D1. The terminal with the same name of N3 is connected to the anode terminal of the rectifier diode D3, the positive pole of the electrolytic capacitor C5 is connected to the cathode of D3, the cathode of D3 is connected to the No. 5 pin of L6561 through the resistor R2, and the negative pole of C5 is connected to the opposite terminal of N3. The terminal with the same name of N2 is connected to the anode of the diode D3, the cathode of D3 is the positive output terminal of the 40V DC voltage, and the terminal with the same name of N2 is connected to the ground (GND2) after being connected in series with the resistor R21. The step-down 1 unit is composed of LM3409 and other components, and its function is to reduce the +40V DC input voltage to the normal working voltage of the LED load. The +40V voltage is connected to the input terminal VIN1 of the step-down unit 1 through the relay RELAY, and the emitter of the transistor Q1 Connected to +5V DC voltage, the base of Q1 is connected to the P3.6 port of the microcontroller after being connected in series with the current limiting resistor R34, the collector of Q1 is connected to the ground (GND2) after the relay RELAY, and the anode of the diode D7 is connected to the ground (GND2 ), the cathode of D2 is connected to the collector of Q1. Capacitors C11 and C12 are respectively connected between VIN1 and ground (GND2). Capacitor C10 is connected between pin 9 and pin 10 of LM3409, pin 8 of LM3409 is connected to power input terminal VIN1, one end of resistor R26 is also connected to pin 8 of LM3409, and one end is connected to MOS tube The drain terminal of MOS2, pin 6 of LM3409 is connected to the gate terminal of MOS2, the source terminal of MOS2 is connected to the cathode of Zener tube D6, and the anode of D6 is connected to ground (GND2). Resistor R24 is connected between pin 1 and pin 10 of LM3409, and pin 1 is connected in series with resistor R23 to ground (GND2). Capacitor C9 is connected between pin 4 and pin 5 of LM3409, one end of resistor R25 is connected to pin 4 of LM3409, and the other end is connected in series with 8 LED beads to ground (GND2). One end of the inductor L3 is connected to the cathode of D6, and the other end is connected between R25 and the LED load. By inputting PWM waveforms with different duty ratios to pin 3 of the LM3409, the brightness of the LED load can be adjusted. The output voltage acquisition unit of the LED load is composed of a resistor R32, a resistor R33 and a capacitor C18. One end of resistor R32 is connected to the output end of step-down unit 1, the other end is connected in series with R33 to ground (GND), capacitor C18 is connected in parallel to both ends of resistor R33, and the P1.0 port of the microcontroller is connected between R32 and R33 to realize LED For the collection of output voltage, the function of capacitor C18 is to filter out high-frequency interference. The step-down 2 unit is composed of TPS54061 and other components, the +40V voltage is connected to the input terminal VIN2 of the step-down 2 unit, one end of the capacitor C13 is connected to the input end, the other end is grounded (GND2), one end of the resistor R26 is connected to the input end, and the other end Connect R27 in series to the ground (GND2), the No. 3 pin of TPS54061 is connected between R26 and R27, and the No. 4 pin of TPS54061 is connected to the ground (GND2) after series resistor R28. Capacitor C14 is connected in parallel between pin 1 and pin 8 of TPS54061, and pin 8 outputs +5V DC voltage through inductor L4. Resistor R29 and capacitor C16 are connected in series with capacitor C15 between pin 6 of TPS54061 and ground (GND2), resistor R31 is connected between ground (GND2) and pin 5 of TPS54061, and one end of resistor R30 is connected to +5V output terminal, one end is connected to pin 5 of TPS54061. Pin 7 of TPS54061 is directly grounded (GND), and capacitor C17 is connected between +5V and ground (GND2). The constant current and voltage limiting loop is composed of a voltage regulator chip TL431, an operational amplifier, and a linear optocoupler PC817. One end of resistor R20 is connected to the ground (GND2), the other end is connected to the positive input end of AM1, one end of resistor R17 is connected to the reference end (3) of TL431, the other end is connected to the negative input end of AM1, and then resistor R15 is connected in series to Ground (GND2). One end of resistor R22 is connected to the positive output terminal of +40V, the other end is connected to the cathode terminal (2) of TL431, and then resistor R18 is connected in series to the negative input terminal of AM2. One end of the resistor R19 is connected to the positive output terminal of +40V, the other end is connected to the positive output terminal of AM2, and then the resistor R16 is connected in series to the ground (GND2). The output terminal of AM1 is connected to the anode terminal of diode D4, the output terminal of AM2 is connected to the anode terminal of diode D5, the cathodes of D4 and D5 are connected together, and then the resistor R12 is connected in series to the anode terminal of the light-emitting diode of PC817, and the capacitor C6 is connected in parallel At both ends of R12, resistor R14 is connected in parallel to the negative input terminal and output terminal of AM1, and resistor R13 is connected in parallel to the negative input terminal and positive output terminal of AM2. The collector of the phototransistor of PC817 is connected to the cathode terminal of D3, one end of the resistor R10 is connected to the end of the same name of N2, and the other end is connected to the collector of the phototransistor of PC817. One end of the resistor R9 is connected to the ground (GND1), and the other end is connected to the emitter of the phototransistor of PC817. A capacitor C19 is connected in series between GND1 and GND2.

As shown in Figure 3, the circuit mainly includes the minimum system circuit of the single-chip microcomputer, the external clock circuit of DS1302, and the external storage circuit of E ² PROOM; GND) to ground (GND2). The positive pole of the electrolytic capacitor C20 is connected to the positive pole of the +5V power supply, the negative pole of C20 is connected to pin 9 (RST) of the microcontroller and the resistor R34 is connected in series to the ground (GND2), and the switch S1 is connected in parallel to both ends of C20. One end of the resistance exclusion RES is connected to the positive pole of the +5V power supply, and the other end is respectively connected to P0.0, P0.1, P0.2, P0.3, P0.4, P0.5, P0.6, and P0.7. Both ends of crystal oscillator Y1 are connected to pins 18 and 19 of the microcontroller, and capacitors C21 and C22 are respectively connected to both ends of Y1 and ground (GND2). In the external clock circuit of DS1302, pin 1 of DS1302 is connected to the positive pole of +5V power supply, and pin 4 is grounded (GND2). Pin 2 and pin 3 are respectively connected to the two ends of the crystal oscillator Y2, and pin 8 is connected to the positive pole of the button battery. One end of the resistors R35, R36, R37 is connected to the positive pole of the +5V power supply, and their other ends are respectively connected to pins 7, 6, and 5 of D1302, and pins 21, 22, and 23 of the microcontroller are respectively connected to pins 7 , 6, and 5 pins. In the circuit diagram of the external storage unit, pins 1, 2, 3, and 8 of M24C02BN6 are respectively connected to the positive pole of the +5V power supply. Pin 4 of M24C02BN6 is connected to ground (GND2), and pins 5, 6 and 7 are connected to pins 24, 25 and 26 of the microcontroller respectively.

As shown in Figure 4, the circuit diagram of the 12864 liquid crystal display unit, the 1st pin of the 12864 liquid crystal is grounded (GND2), the 2nd pin is connected to the positive pole of the +5 DC power supply, and the two ends of the variable resistor R35 are respectively connected to the +5V and the ground ( GND), the variable resistor terminal (3) is connected to the 3rd pin of 12864. Pins 4, 5, and 6 of 12864 LCD are respectively connected to P0.0, P0.1, and P0.2 of the microcontroller. Pins 7, 8, 9, 10, 11, 12, 13, 14, and 15 of 12864 LCD Connect to P0.4, P1.1, P1.2, P1.3, P1.4, P1.5, P1.6, P1.7, P0.3 of the single chip microcomputer respectively. 16 and 18 pins of 12864 LCD are connected to + The positive pole of the 5V power supply, pins 17 and 19 are floating, and pin 20 is grounded (GND2).

As shown in Figure 5, the circuit diagram of the buzzer alarm unit, the emitter of the triode Q2 is connected to the positive pole of +5V power supply, the base is connected to the current limiting resistor R38 and then connected to P3.3 of the single chip microcomputer, the collector is connected to the buzzer BUZZ and connected in series to limit the current Resistor R39 to ground (GND2).

As shown in Figure 6 is the circuit diagram of the button unit, one end of the buttons K1 and K2 are respectively connected to the single-chip microcomputer P3.4 and P3.5, and the other ends are connected to the ground (GND2).

As shown in Figure 7 is the circuit diagram of the 232 serial port unit. Capacitors C23, C24, C25, and C26 are respectively connected between pins 1 and 3, pins 4 and 5, pins 2 and 16, pins 6 and 15 of the MAX3232. Pins 11 and 12 of MAX3232 are respectively connected to P3.1 and P3.0 of the microcontroller, and pins 10, 9, 7, and 8 of MAX3232 are suspended. Pin 2 of the serial port interface J1 is connected to pin 14 of the MAX3232, pin 3 of J1 is connected to pin 13 of the MAX3232, pin 5 of J1 is grounded (GND2), and other pins of J1 are suspended.

As shown in Figure 8 is the circuit diagram of the temperature acquisition unit, the 1st pin of 18B20 is grounded (GND2), the 2nd pin is connected to the P0.4 of the microcontroller, the 3rd pin is connected to the +5V DC power supply positive pole, and the resistor R40 is connected Between pin 2 and pin 3 of 18B20.

Claims (14)

1. A new type of LED drive power supply, characterized by comprising: EMI filter unit, rectifier filter unit, power factor correction unit, flyback conversion unit, constant current limit voltage feedback unit, step-down 1 unit, step-down 2 unit, LED Load unit, microcontroller unit, E ² PROOM memory unit, clock circuit unit, temperature acquisition unit, output voltage sampling unit, liquid crystal display unit, 232 serial port unit; 220V AC voltage is connected to the rectification filter unit and power factor after passing through the EMI filter unit The correction unit, the power factor correction unit is connected to the flyback conversion unit, the constant current limiting voltage feedback unit is between the flyback conversion unit and the secondary rectification unit, and the step-down 1 unit and step-down 2 unit are respectively connected to the output of the secondary rectification terminals, used to generate +20V DC voltage and +5V DC voltage respectively; step-down 1 unit connects LED loads in series, step-down 2 units supply power to the single-chip microcomputer; single-chip microcomputer unit and E ² PROOM memory unit, clock unit, temperature acquisition unit, alarm unit, liquid crystal display unit, 232 serial port unit, and key unit are connected, and the voltage sampling unit and temperature acquisition unit respectively collect the output voltage and real-time temperature of the LED load, which are transmitted to the single-chip microcomputer unit after the AD conversion unit, and the clock circuit unit generates accurate Time parameters, the single-chip unit sends the information of time, temperature and voltage to the E ² PROOM memory unit for storage and display on the liquid crystal display unit; the human-computer interaction can be realized through the 232 serial port unit, and the time stored in the E ² PROOM memory unit can be read , Real-time ambient temperature and output voltage information, you can also set the upper and lower limits of output voltage and temperature in abnormal situations to the microcontroller. When the parameters of output voltage sampling or temperature sampling exceed the set value, the microcontroller unit will control The alarm unit sends out an alarm to remind the staff to come for maintenance, and cuts off the step-down 1 unit circuit through the relay module to protect the LED load; the single-chip unit can generate PWM waves through the button unit, and the PWM waveforms with different duty ratios drive the step-down 1 unit Generate different output voltages to adjust the brightness of the LED load. 2. A new type of LED drive power supply according to claim 1, characterized in that the EMI filter circuit unit is composed of safety capacitors CX1, CX2, CY1, CY2 and common mode inductors L1, L2, and the input end of the EMI filter is connected to 220V AC voltage, the output terminal is connected to the rectification filter unit. 3. A new type of LED drive power supply according to claim 1, characterized in that the rectification and filtering unit is composed of a rectification bridge D25SB80 and a capacitor C1, and the capacitor C1 is connected in parallel at the output end of the rectification bridge. 4. A new type of LED drive power supply according to claim 1, characterized in that the power factor correction unit is composed of components such as the power factor correction chip L6561 produced by ST Company. 5. A new LED drive power supply according to claim 1, characterized in that the constant current limiting voltage feedback unit is composed of an operational amplifier LM358, a three-terminal voltage regulator chip TL431, a linear optocoupler PC817 and the like. 6. A new type of LED drive power supply according to claim 1, characterized in that the step-down unit 1 is composed of a high-precision step-down LED driver chip LM3409 produced by TI, and the LM3409 supports analog dimming and PWM dimming. Changing the duty cycle of the PWM waveform of its input pin can realize the adjustment of LED brightness. 7. A new type of LED driver power supply according to claim 1, characterized in that the step-down unit 2 is composed of a step-down LED driver chip TPS54061 produced by TI company. TPS54061 has the advantages of wide input voltage range and simple peripheral circuit design. , Its internal integrated MOSFET field effect transistor reduces the packaging volume. 8. A new type of LED drive power supply according to claim 1, characterized in that the LED load unit is composed of 8 XPG2 type 5W high-brightness white LED lamp beads of CREE company connected in series, and the XPG2 type LED lamp beads have a long service life , low light decay and other advantages, widely used in high-power lighting and other fields. 9. A new type of LED drive power supply according to claim 1, characterized in that the single-chip microcomputer unit adopts the STC12C5A60S2 single-chip microcomputer chip produced by STC Company, the STC12C5A60S2 single-chip microcomputer chip has the advantages of fast working speed and low power consumption, and the power supply of the single-chip microcomputer For +5V DC power supply. 10. A new type of LED drive power supply according to claim 1, characterized in that the E ² PROOM memory unit is composed of the I ² C bus-based E ² PROOM memory M24C02BN6 produced by ST Company, M24C02BN6 has a large capacity and long data retention time Long and other advantages. 11. A new type of LED drive power supply according to claim 1, characterized in that the clock unit is composed of a real-time clock chip DS1302 produced by DALLAS company, which has the advantages of high precision, low power consumption, and simple peripheral circuits. 12. A new type of LED drive power supply according to claim 1, characterized in that the temperature acquisition unit is composed of temperature sensor DS18B20 and other components produced by DALLAS company, and its advantages are small size, high temperature measurement resolution, and strong anti-interference ability . 13. A new LED drive power supply according to claim 1, characterized in that the liquid crystal display unit adopts 12864 type LCD liquid crystal. 14. A new type of LED drive power supply according to claim 1, characterized in that the 232 serial port unit is composed of components such as a level conversion chip MAX3232.