800V high voltage input 15V direct current power supply circuit

Abstract

The utility model relates to the technical field of rectifier modules of a high-power communication power supply system, and discloses an 800V high-voltage input 15V direct-current power supply circuit, which adopts a primary voltage division flyback DC-DC conversion circuit topological structure formed by connecting two MOSFETs in series, the two MOSFETs complete the voltage division work of 800V direct-current high voltage, and the problem that the withstand voltage of a single MOSFET is not enough is solved; the PWM signal control drive circuit adjusts the waveform duty ratio of PWM signals output by the control chip UCC28C45D according to the output power of the direct-current power supply by adjusting output voltage and current feedback balance, so that the working state of an MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) is adjusted and controlled, the effects of output voltage stabilization and power supply efficiency improvement are achieved, and the control circuit has the characteristics of simplicity and high efficiency; the input filter circuit and the output filter circuit adopt typical LC filter circuits to filter high-frequency clutters of input and output signals, so that the input and output waveforms of the direct-current power supply are more standard and cleaner.

Description

Technical Field

[0001] The utility model relates to the technical field of rectifier modules of high-power communication power supply systems, in particular to an 800V high-voltage input 15V direct current power supply circuit. Background Art

[0002] The National Telecommunications Central Bureau Station uses a large number of high-power communication power supply high-frequency switching rectifiers for power supply. Now, because the module power of 5000W high-power communication high-frequency switching rectifier is very large, it generally uses three-phase AC balanced current input, which prompts the three-phase PFC energy storage circuit output to increase the main circuit power while reducing the total current by boosting it to 800V DC high voltage.

[0003] The auxiliary power supply of the rectifier module requires 800V high voltage input. The output power, working efficiency and other indicators of the ordinary flyback DC-DC conversion circuit cannot meet the requirements with the voltage resistance design of the main power device MOSFET tube. Two MOSFET tubes must be connected in series to integrate the topology of the primary voltage-dividing flyback DC-DC conversion circuit to meet the technical requirements. The ordinary flyback DC-DC conversion circuit cannot solve the above problems. Therefore, we need to design a 800V high voltage input 15V DC power supply circuit to solve the above problems. Utility Model Content

[0004] The utility model aims to provide an 800V high-voltage input 15V DC power supply circuit, which adopts two MOSFET tubes connected in series for primary voltage division flyback DC-DC conversion circuit topology. The two MOSFET tubes complete the voltage division work of the 800V DC high voltage, solving the problem of insufficient voltage resistance of a single MOSFET tube; the PWM signal control driving circuit adjusts the waveform duty cycle of the PWM signal output by the control chip UCC28C45D according to the output power of the DC power supply by adjusting the output voltage and current feedback balance, thereby adjusting and controlling the working state of the MOSFET tube to achieve the effect of output voltage stabilization and improving power supply efficiency, and the control circuit has the characteristics of simplicity and high efficiency; the input filter circuit and the output filter circuit adopt typical LC filter circuits to filter the high-frequency clutter of the input and output signals, so that the DC power supply input and output waveforms are more standard and clean, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: an 800V high-voltage input 15V DC power supply circuit, comprising an input rectifier and filter circuit whose input end is connected to an 800V input high-voltage DC power, a DC-DC conversion circuit, an output rectifier and filter circuit whose output end can output multiple 15V DC power, a PWM signal control drive circuit, and a transformer T1, wherein the input rectifier and filter circuit, the DC-DC conversion circuit, and the output rectifier and filter circuit are connected in sequence, the DC-DC conversion circuit is connected to the PWM signal control drive circuit, and the DC-DC conversion circuit, the output rectifier and filter circuit, and the PWM signal control drive circuit are all connected to the transformer T1;

[0006] The input rectification and filtering circuit includes a diode D1 for rectifying the input DC high voltage signal, a capacitor C1 and a capacitor C2 connected in series for input filtering;

[0007] The main components of the DC-DC conversion circuit include a MOSFET tube Q1 and a MOSFET tube Q2 arranged in series, the MOSFET tubes Q1 and Q2 are connected to an absorption circuit capable of absorbing reverse electric energy generated by flyback DC-DC conversion, and the MOSFET tubes Q1 and Q2 are connected to a main circuit current detection circuit;

[0008] The output rectification and filtering circuit comprises an output rectification loop composed of a diode D16, a diode D17 and a diode D18, an RC absorption circuit is connected in parallel to the output rectification loop, and one end of the output rectification loop is connected to a DC power supply output filtering circuit.

[0009] Preferably, the PWM signal control driving circuit includes a PWM control chip U1 for controlling the operation of the MOSFET tube Q1 and the MOSFET tube Q2, a capacitor C13 is connected in parallel between pin 1 and pin 2 of the PWM control chip U1, a capacitor C12 and a resistor R37 are connected in parallel to the capacitor C13, the connection terminals of the capacitor C12 and the capacitor C13 are connected to pin 1 of the diode D13, a resistor R35 is connected between pin 2 and pin 3 of the diode D13, pin 3 of D13 is connected to one end of the capacitor C11, a capacitor C16 is connected to pin 3 of the PWM control chip U1, and a capacitor C15 is connected to pin 4 of the PWM control chip U1. The 8th pin of the PWM control chip U1 is connected to capacitor C14, a resistor R38 is connected between pins 4 and 8 of the PWM control chip U1, a diode D14 is connected to pin 6 of the PWM control chip U1, a resistor R36 is connected to pin 2 of the PWM control chip U1, a capacitor C10, a resistor R34 and a resistor R33 are connected in parallel between one end of the resistor R36 and the connection terminals of the capacitors C14, C15, C16 and diode D14, a resistor R32 and a capacitor C9 are also connected in parallel to one end of the resistor R36, and resistors R1, R2, R3 and R4 are connected in series to pin 7 of the PWM control chip U1.

[0010] Preferably, the PWM signal control drive circuit also includes a transformer T2 and a MOSFET tube Q5, pin 1 of the transformer T2 is connected to pin 7 of the PWM control chip U1, and pin 2 of the transformer T2 is connected to a diode D7, and a Zener diode ZD1, a capacitor C5, a capacitor C6 and a capacitor C7 arranged in parallel are connected between the diode D7 and pin 7 of the PWM control chip U1, a diode D6, a resistor R9 and a capacitor C8 are connected in series between the two ends of the capacitor C7, one end of the capacitor C8 is connected to pin 7 of the transformer T1, and a diode D5, a diode D4, a capacitor C4 and a resistor R10 arranged in parallel are connected between the other end of the capacitor C8 and pin 8 of the transformer T1.

[0011] Preferably, the transformer T2 is connected with a driving circuit 1 for driving the MOSFET tube Q1 and a driving circuit 2 for driving the MOSFET tube Q2, wherein the main component of the driving circuit 1 includes the transistor Q3, and the main component of the driving circuit 2 includes the transistor Q4.

[0012] Preferably, a resistor R21, a diode D8, and a resistor R18 are connected between the base and the emitter of the transistor Q3, a resistor R22 is connected between the base and the collector of the transistor Q3, a resistor R23 and a resistor R20 are connected between the collector and the emitter of the transistor Q3, a resistor R19 is connected in parallel to the resistor R20, the connecting end of the resistor R21 and the diode D8 is connected to pin 10 of the transformer T2, and the collector of the transistor Q3 is connected to pin 9 of the transformer T2.

[0013] Preferably, the D pole of the MOSFET tube Q5 is connected to the 5th pin of the transformer T2, a capacitor C17 is connected between the S pole of the MOSFET tube Q5 and the 4th pin of the transformer T2, a resistor R42 is connected between the G pole and the S pole of the MOSFET tube Q5, a resistor R40 is connected between the G pole of the MOSFET tube Q5 and the 6th pin of the PWM control chip U1, and a resistor R39 and a diode D15 are connected in series in parallel to the resistor R40.

[0014] Preferably, a resistor R27, a diode D11, and a resistor R24 ​​are connected between the base and the emitter of the transistor Q4, a resistor R28 is connected between the base and the collector of the transistor Q4, a resistor R26 and a resistor R29 are connected between the collector and the emitter of the transistor Q4, a resistor R25 is connected in parallel to the resistor R26, the connecting end of the resistor R27 and the diode D11 is connected to pin 7 of the transformer T2, and the collector of the transistor Q4 is connected to pin 6 of the transformer T2.

[0015] Preferably, the G pole of the MOSFET tube Q1 in the DC-DC conversion circuit is connected to the driving circuit one, the G pole of the MOSFET tube Q2 in the DC-DC conversion circuit is connected to the driving circuit two, the D pole of the MOSFET tube Q1 is connected to a diode D3, one end of the diode D3 is connected to the 10th pin of the transformer T1, a diode D2 and a capacitor C3 are connected between the 9th pin and the 10th pin of the transformer T1, the connection terminals of the diode D2 and the capacitor C3 are connected to a series resistor R5 and a resistor R6, and a series resistor R7 and a resistor R8, and the connection terminals of the resistor R5 and the resistor R7 are connected to the diode D1.

[0016] Preferably, the DC-DC conversion circuit further includes a transformer CT1, wherein the pin 1 of the transformer CT1 is connected to resistors R11, R12 and R13 which are arranged in parallel via resistors R30 and R31 which are arranged in series with the pin 3 of the transformer CT1, wherein one terminal of the resistors R11, R12 and R13 is connected to the S pole of the MOSFET tube Q1, and the other terminals of the resistors R11, R12 and R13 are connected to the pin 2 of the transformer T1, and a diode D10 is connected between the D pole of the MOSFET tube Q2 and the pin 1 of the transformer T1;

[0017] The resistor R29 is connected between the G pole and the S pole of the MOSFET tube Q2, the S pole of the MOSFET tube Q2 is connected to the 6th pin of the transformer CT1, the capacitor C29 and the diode D9 are connected between the 1st pin and the 2nd pin of the transformer T1, the capacitor C29 is connected in parallel with the series resistor R14 and the resistor R15, the resistor R14 and the resistor R15 are connected in parallel with the series resistor R16 and the resistor R17, the 4th pin of the transformer CT1 is respectively connected with the diode D12 and the series capacitor C2 and the capacitor C1, and one end of the capacitor C1 is connected to the diode D1.

[0018] Preferably, the diode D16 is connected to pin 12 of the transformer T1, the diode D17 is connected to pin 4 of the transformer T1, the diode D18 is connected to pin 5 of the transformer T1, the RC absorption circuit includes a resistor R43, a resistor R44 and a capacitor C18 connected in parallel to the diode D16, a resistor R45 and a capacitor C23 connected in parallel to the diode D17, a resistor R47 and a capacitor C26 connected in parallel to the diode D18, the secondary DC power supply LC filter circuit includes a capacitor C19, a capacitor C20, a capacitor C21, and a capacitor C22 connected in parallel between pin 11 of the transformer T1 and one end of the diode D16, and the two ends of the capacitor C22 are respectively connected to an inductor L1 and an inductor L2, and the primary DC power supply filter circuit includes a capacitor C24, a capacitor C25 connected in parallel between pin 3 of the transformer T1 and one end of the diode D17, and a capacitor C27 and a capacitor C28 connected in parallel between pin 3 of the transformer T1 and one end of the diode D18.

[0019] Compared with the prior art, the beneficial effects of the utility model are:

[0020] 1. The utility model adopts two MOSFET tubes connected in series to perform the primary voltage-dividing flyback DC-DC conversion circuit topology. The two MOSFET tubes complete the voltage-dividing work of the 800V DC high voltage, solving the problem of insufficient voltage resistance of a single MOSFET tube;

[0021] 2. The PWM signal control driving circuit of the utility model adjusts the output voltage and current feedback balance, adjusts the waveform duty cycle of the PWM signal output by the control chip UCC28C45D according to the output power of the DC power supply, thereby adjusting and controlling the working state of the MOSFET tube to achieve the effect of output voltage stabilization and improve power supply efficiency. The control circuit has the characteristics of simplicity and high efficiency;

[0022] 3. The input filter circuit and output filter circuit of the utility model adopt typical LC filter circuit to filter high-frequency noise of input and output signals, making the DC power supply input and output waveforms more standard and clean. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a circuit diagram of the utility model;

[0024] Figure 2 A circuit diagram of the utility model;

[0025] Figure 3 This is a circuit diagram of the input rectifier and filter circuit of the utility model;

[0026] Figure 4 The circuit diagram of the output rectifier and filter circuit of the utility model;

[0027] Figure 5 This is a circuit diagram of a PWM signal controlled driving circuit of the utility model;

[0028] Figure 6 The utility model is a circuit diagram of a DC-DC conversion circuit. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0030] See also Figure 1-6The utility model provides a technical solution: an 800V high-voltage input 15V DC power supply circuit, comprising an input rectifier filter circuit with an input end connected to an 800V input high-voltage DC power, a DC-DC conversion circuit, an output rectifier filter circuit with an output end capable of outputting multiple 15V DC power, a PWM signal control drive circuit, and a transformer T1, wherein the input rectifier filter circuit, the DC-DC conversion circuit, and the output rectifier filter circuit are connected in sequence, the DC-DC conversion circuit is connected to the PWM signal control drive circuit, and the DC-DC conversion circuit, the output rectifier filter circuit, and the PWM signal control drive circuit are all connected to the transformer T1;

[0031] The input rectification and filtering circuit includes a diode D1 for rectifying the input DC high voltage signal, a capacitor C1 and a capacitor C2 connected in series for input filtering;

[0032] Capacitors C1 and C2 are connected in series to perform primary voltage division filtering, which plays the role of filtering input high-frequency noise.

[0033] The anode of the diode D1 is connected to +400V DC, the cathode of the diode D1 is electrically connected to one end of the capacitor C1, the other end of the capacitor C1 is electrically connected to one end of the capacitor C2, and the other end of the capacitor C2 is connected to -400V DC.

[0034] The main components of the DC-DC conversion circuit include a MOSFET tube Q1 and a MOSFET tube Q2 arranged in series, the MOSFET tubes Q1 and Q2 are connected to an absorption circuit capable of absorbing reverse electric energy generated by flyback DC-DC conversion, and the MOSFET tubes Q1 and Q2 are connected to a main circuit current detection circuit;

[0035] The DC-DC conversion circuit is composed of resistor R5, resistor R6, resistor R7, resistor R8, resistor R11, resistor R12, resistor R13, resistor R14, resistor R15, resistor R16, resistor R17, capacitor C3, capacitor C29, diode D2, diode D3, diode D9, diode D10, diode D12, MOSFET tube Q1, MOSFET tube Q2, mutual inductor CT1, and transformer T1 primary windings T1-1, T1-2, T1-9, and T1-10.

[0036] One end of the resistor R5 is electrically connected to one end of the resistor R6, one end of the resistor R7 is electrically connected to one end of the resistor R8, the other end of the resistor R5, the other end of the resistor R7, and one end of the capacitor C3 are electrically connected to pin 9 of the transformer T1, the other end of the resistor R6, the other end of the resistor R8, and the other end of the capacitor C3 are electrically connected to the cathode of the diode D2, the anode of the diode D2, the anode of the diode D3 are electrically connected to pin 10 of the transformer T1, the cathode of the diode D3 is electrically connected to the source of the MOSFET tube Q1, the drain of the MOSFET tube Q1 is electrically connected to one end of the resistor R11, one end of the resistor R12, and one end of the resistor R13, the other end of the resistor R11, the other end of the resistor R12, the other end of the resistor R13, one end of the resistor R14, and the resistor R16 One end of the resistor R14 and one end of the capacitor C29 are electrically connected to pin 2 of the transformer T1 and pin 3 of the primary winding of the transformer CT1. The other end of the resistor R14 is electrically connected to one end of the resistor R15. The other end of the resistor R16 is electrically connected to one end of the resistor R17. The other end of the resistor R15, the other end of the resistor R17 and the other end of the capacitor C29 are electrically connected to the cathode of the diode D9. The anode of the diode D9 and the anode of the diode D10 are electrically connected to pin 1 of the initial winding of the transformer T1. The cathode of the diode D10 is electrically connected to the drain of the MOSFET tube Q2. The source of the MOSFET tube Q2 is electrically connected to pin 6 of the transformer CT1. The anode of the diode D12 is electrically connected to pin 4 of the transformer CT1. The cathode of the diode D12 is connected to the 800V DC high voltage working ground.

[0037] The working principle is to use two MOSFET tubes in series to perform the primary voltage division flyback DC-DC conversion circuit topology, and use MOSFET tubes Q1 and MOSFET tubes Q2 to divide the voltage. Resistor R5, resistor R6, resistor R7, resistor R8, resistor R14, resistor R15, resistor R16, resistor R17, capacitor C3, capacitor C29, diode D2, and diode D9 form a reverse power absorption circuit to absorb the reverse power generated by the flyback DC-DC conversion. Resistor R11, resistor R12, resistor R13, and transformer CT1 play the role of DC-DC conversion main circuit current detection. Diode D3, diode D10, and diode D12 play the role of controlling the unidirectional flow of the DC-DC conversion main circuit current direction.

[0038] The output rectification and filtering circuit comprises an output rectification loop composed of a diode D16, a diode D17 and a diode D18, an RC absorption circuit is connected in parallel to the output rectification loop, and one end of the output rectification loop is connected to a DC power supply output filtering circuit.

[0039] The output rectifier and filter circuit is composed of resistor R43, resistor R44, resistor R45, resistor R46, resistor R47, resistor R48, capacitor C18, capacitor C19, capacitor C20, capacitor C21, capacitor C22, capacitor C23, capacitor C24, capacitor C25, capacitor C26, capacitor C27, capacitor C28, inductor L1, inductor L2, diode D16, diode D17, diode D18, transformer T1 primary windings T1-3, T1-4, T1-5, and secondary windings T1-11, T1-12.

[0040] Pin 12 of transformer T1 is electrically connected to one end of resistor R43, one end of resistor R44, and the positive electrode of diode D16. The other end of resistor R43, the other end of resistor R44 is electrically connected to one end of capacitor C18. The other end of capacitor C18 is electrically connected to the negative electrode of diode D16, one end of capacitor C19, one end of capacitor C20, one end of capacitor C21, one end of capacitor C22, and one end of inductor L1. The other end of inductor L1 outputs +15V power supply. Pin 11 of transformer T1 is electrically connected to the other end of capacitor C19, the other end of capacitor C20, the other end of capacitor C21, the other end of capacitor C22, and one end of inductor L2. The other end of inductor L2 is connected to the secondary working ground. Pin 3 of transformer T1 is electrically connected to one end of capacitor C24, one end of capacitor C25, and resistor One end of R46, one end of capacitor C27, one end of capacitor C28, and one end of resistor R48 are connected to the primary working ground, pin 4 of transformer T1 is electrically connected to one end of resistor R45 and the positive electrode of diode D17, the other end of resistor R45 is electrically connected to one end of capacitor C23, the other end of capacitor C23, the negative electrode of diode D17, the other end of capacitor C24, the other end of capacitor C25, and the other end of resistor R46 output +15VP power supply, pin 5 of transformer T1 is electrically connected to one end of resistor R47 and the negative electrode of diode D18, the other end of resistor R47 is electrically connected to one end of capacitor C26, the other end of capacitor C26, the positive electrode of diode D18, the other end of capacitor C27, the other end of capacitor C28, and the other end of resistor R48 output -15VP power supply.

[0041] The working principle is to output 1 +15V secondary DC power supply and 2 ±15VP primary DC power supplies respectively after rectification and filtering by the rectifier and filter circuit, which respectively power the primary and secondary control circuits of the module. The total output power of the DC power supply reaches up to 50 watts. Diode D16, diode D17, and diode D18 play the role of output rectification. Resistor R43, resistor R44, resistor R45, resistor R47, capacitor C18, capacitor C23, and capacitor C26 form an RC absorption circuit to absorb the working peak noise of the output rectifier diode D16, diode D17, and diode D18. Capacitor C19, capacitor C20, capacitor C21, capacitor C22, inductor L1, and inductor L2 form a secondary DC power supply LC filter circuit, and capacitor C24, capacitor C25, capacitor C27, and capacitor C28 form a primary DC power supply filter circuit, making the DC power supply output waveform more standard and clean.

[0042] The PWM signal control driving circuit includes a PWM control chip U1 for controlling the operation of the MOSFET tube Q1 and the MOSFET tube Q2. A capacitor C13 is connected in parallel between pins 1 and 2 of the PWM control chip U1. A capacitor C12 and a resistor R37 are connected in parallel to the capacitor C13. The connection terminals of the capacitors C12 and C13 are connected to pin 1 of the diode D13. A resistor R35 is connected between pins 2 and 3 of the diode D13. Pin 3 of D13 is connected to one end of the capacitor C11. Pin 3 of the PWM control chip U1 is connected to a capacitor C16. Pin 4 of the PWM control chip U1 is connected to a capacitor C15. Capacitor C14 is connected to pin 8 of the WM control chip U1, resistor R38 is connected between pins 4 and 8 of the PWM control chip U1, diode D14 is connected to pin 6 of the PWM control chip U1, resistor R36 is connected to pin 2 of the PWM control chip U1, capacitor C10, resistor R34 and resistor R33 are connected in parallel between one end of the resistor R36 and the connection terminals of capacitor C14, capacitor C15, capacitor C16 and diode D14, resistor R32 and capacitor C9 are also connected to one end of the resistor R36 in parallel, and resistor R1, resistor R2, resistor R3 and resistor R4 are connected in series to pin 7 of the PWM control chip U1.

[0043] The PWM signal control driving circuit also includes a transformer T2 and a MOSFET tube Q5. Pin 1 of the transformer T2 is connected to pin 7 of the PWM control chip U1. Pin 2 of the transformer T2 is connected to a diode D7. A Zener diode ZD1, a capacitor C5, a capacitor C6 and a capacitor C7 arranged in parallel are connected between the diode D7 and pin 7 of the PWM control chip U1. A diode D6, a resistor R9 and a capacitor C8 are connected in series between the two ends of the capacitor C7. One end of the capacitor C8 is connected to pin 7 of the transformer T1, and a diode D5, a diode D4, a capacitor C4 and a resistor R10 arranged in parallel are connected between the other end of the capacitor C8 and pin 8 of the transformer T1.

[0044] Pin 1 of the PWM control chip U1 is electrically connected to one end of the capacitor C13, one end of the capacitor C12, and pin 1 of the diode D13; pin 2 of the PWM control chip U1 is electrically connected to the other end of the capacitor C13, one end of the resistor R37, and one end of the resistor R36; the other end of the capacitor C12 is electrically connected to the other end of the resistor R37; pin 2 of the diode D13 and one end of the resistor R35 are connected to a +5VREFP power supply; the other end of the resistor R35 is electrically connected to pin 3 of the diode D13 and one end of the capacitor C11; pin 8 of the PWM control chip U1 is connected to one end of the resistor R38 and one end of the capacitor C14 to output a +5VREFP power supply;

[0045] Pin 4 of the PWM control chip U1 is electrically connected to the other end of the resistor R38 and one end of the capacitor C15. Pin 5 of the PWM control chip U1 is electrically connected to the other end of the capacitor C15, the other end of the capacitor C14, the other end of the capacitor C11, one end of the capacitor C10, one end of the resistor R34, one end of the resistor R33, one end of the capacitor C16, the positive electrode of the diode D14, one end of the resistor R42, the source of the transistor Q5, and one end of the capacitor C17, and the other end of the capacitor C10 is electrically connected to the other end of the resistor R36, the other end of the resistor R34, the other end of the resistor R33, one end of the resistor R32, and one end of the capacitor C9. The other end of the resistor R32 and the other end of the capacitor C9 are connected to the +18VP power supply voltage.

[0046] Pin 3 of the PWM control chip U1 is electrically connected to the other end of the capacitor C16 and one end of the resistor R41, pin 6 of the PWM control chip U1 is electrically connected to the cathode of the diode D14, one end of the resistor R39, and one end of the resistor R40, pin 7 of the PWM control chip U1 is electrically connected to one end of the resistor R4, the cathode of the Zener diode DZ1, one end of the capacitor C5, one end of the capacitor C6, the anode of the capacitor C7, the cathode of the diode D6, pin 1 of the transformer T2, pin 4 of the transformer T2, and the other end of the capacitor C17 to the +18VD power supply voltage, resistor R4 is connected in series with resistors R3, R2, and R1 in sequence to the cathode of the diode D1, the other end of the resistor R41 is electrically connected to one end of the resistor R30 and one end of the resistor R31, and the other end of the resistor R39 is electrically connected to the cathode of the diode D15;

[0047] The anode of the diode D15 is electrically connected to the other end of the resistor R40, the other end of the resistor R42, and the gate of the transistor Q5. The drain of the transistor Q5 is electrically connected to the pin 5 of the transformer T2. The anode of the Zener diode DZ1, the other end of the capacitor C5, the other end of the capacitor C6, the negative electrode of the capacitor C7, one end of the capacitor C8, the pin 7 of the transformer T1, and the anode of the diode D7 are connected to the primary working ground. The negative electrode of the diode D7 is electrically connected to the pin 2 of the transformer T2. The anode of the diode D6 is electrically connected to one end of the resistor R9.

[0048] The other end of the resistor R9, the other end of the capacitor C8, the cathode of the diode D4, the cathode of the diode D5, and one end of the capacitor C4 output a +18VP power supply, the other end of the capacitor C4 is electrically connected to one end of the resistor R10, the other end of the resistor R10 is electrically connected to the anode of the diode D4, the anode of the diode D5, and the pin 8 of the transformer T1, the other end of the resistor R30 is electrically connected to one end of the resistor R23, the collector of the transistor Q3, one end of the resistor R22, and the pin 9 of the transformer T2, and the pin 10 of the transformer T2 is electrically connected to one end of the resistor R21 and the anode of the diode D8;

[0049] The other end of the resistor R21 is electrically connected to the other end of the resistor R22 and the base of the transistor Q3, the cathode of the diode D8 is electrically connected to one end of the resistor R18, the other end of the resistor R18 is electrically connected to one end of the resistor R19, one end of the resistor R20, and the emitter of the transistor Q3, the other end of the resistor R19, the other end of the resistor R20 and the other end of the resistor R23 are electrically connected, and the pin 7 of the transformer T2 is electrically connected to one end of the resistor R27 and the anode of the diode D11;

[0050] Pin 6 of transformer T2 is electrically connected to one end of resistor R28, the collector of transistor Q4, and one end of resistor R29. The other end of resistor R27 is electrically connected to the other end of resistor R28 and the base of transistor Q4. The cathode of diode D11 is electrically connected to one end of resistor R24. The other end of resistor R24 ​​is electrically connected to the emitter of transistor Q4, one end of resistor R25, and one end of resistor R26. The other end of resistor R25, the other end of resistor R26, and the other end of resistor R29 are electrically connected.

[0051] The transformer T2 is connected with a driving circuit 1 for driving the MOSFET tube Q1 and a driving circuit 2 for driving the MOSFET tube Q2. The main component of the driving circuit 1 includes a transistor Q3, and the main component of the driving circuit 2 includes a transistor Q4.

[0052] A resistor R21, a diode D8, and a resistor R18 are connected between the base and the emitter of the transistor Q3, a resistor R22 is connected between the base and the collector of the transistor Q3, a resistor R23 and a resistor R20 are connected between the collector and the emitter of the transistor Q3, a resistor R19 is connected in parallel to the resistor R20, the connecting end of the resistor R21 and the diode D8 is connected to pin 10 of the transformer T2, and the collector of the transistor Q3 is connected to pin 9 of the transformer T2.

[0053] The D pole of the MOSFET tube Q5 is connected to the 5th pin of the transformer T2, a capacitor C17 is connected between the S pole of the MOSFET tube Q5 and the 4th pin of the transformer T2, a resistor R42 is connected between the G pole and the S pole of the MOSFET tube Q5, a resistor R40 is connected between the G pole of the MOSFET tube Q5 and the 6th pin of the PWM control chip U1, and a resistor R39 and a diode D15 are connected in series in parallel to the resistor R40.

[0054] A resistor R27, a diode D11, and a resistor R24 ​​are connected between the base and the emitter of the transistor Q4, a resistor R28 is connected between the base and the collector of the transistor Q4, a resistor R26 and a resistor R29 are connected between the collector and the emitter of the transistor Q4, a resistor R25 is connected in parallel to the resistor R26, the connecting end of the resistor R27 and the diode D11 is connected to pin 7 of the transformer T2, and the collector of the transistor Q4 is connected to pin 6 of the transformer T2.

[0055] The PWM control chip U1 (UCC28C45D) is the core of the circuit, generating PWM high-frequency pulse width signals to control and drive the flyback DC-DC converter circuit MOSFET tube Q1 and MOSFET tube Q2. The UCC28C45D chip is a widely used, wide voltage range input, precise control, stable and reliable current control type PWM signal generator.

[0056] Resistor R1, resistor R2, resistor R3, resistor R4, resistor R9, resistor R10, capacitor C4, capacitor C5, capacitor C6, capacitor C7, capacitor C8, diode D4, diode D5, diode D6, Zener diode ZD1, transformer T1 primary winding T1-7, T1-8 constitute the power supply circuit of chip U1. When there is 800V high voltage DC at the DC power input end, the voltage is stepped down through resistor R1, resistor R2, resistor R3, and resistor R4 in series to provide 8.5V starting power supply for PWM control chip U1. PWM control chip U1 outputs PWM signal to trigger MOSFET tube Q1 and MOSFET tube Q2 to work, so as to make transformer T1 primary winding T1-7, T1-8, diode D4, diode D5, and diode D6 work, so as to provide long-term freewheeling power supply for the power supply end of PWM control chip U1.

[0057] Resistor R30, resistor R31, resistor R41, and capacitor C16 form an overcurrent detection protection circuit of the PWM control chip U1. When the main loop current reaches the upper limit value, the output PWM control signal is turned off by the PWM control chip U1, thereby shutting down the operation of MOSFET tubes Q1 and Q2.

[0058] like Figure 5 As shown, one end of the resistor R30 and the resistor R31 are electrically connected to the resistor R41, the other end of the resistor R30 is electrically connected to the resistor R11, and the other end of the resistor R31 is electrically connected to the 1st pin of the transformer CT1. The resistor R32, the resistor R33, the resistor R34, the resistor R35, the resistor R36, the resistor R37, the capacitor C9, the capacitor C10, the capacitor C11, the capacitor C12, the capacitor C13, and the diode D13 form the Vfb feedback control loop of the PWM control chip U1. The +18VP primary power supply output voltage is compared and calculated through the feedback control loop Vfb and output to the COMP function terminal of the PWM control chip U1. At the same time, the DC power supply output power size adjusts the waveform duty cycle of the PWM signal output by the PWM control chip U1 through current feedback, thereby adjusting and controlling the working state of the MOSFET tube Q1 and the MOSFET tube Q2, achieving the effect of output voltage stabilization and improving power supply efficiency. When the output voltage of the +18VP primary power supply is too high, the PWM signal output by the PWM control chip U1 is turned off, and the MOSFET tubes Q1 and Q2 are turned off to achieve output overvoltage protection.

[0059] Capacitor C17, diode D7, MOSFET tube Q5, transformer T2 primary winding T2-1, T2-2, T2-4, T2-5 form a flyback DC-DC conversion circuit to provide PWM control signals for the gate drive circuits of MOSFET tubes Q1 and Q2 to enhance the load driving capability. Resistors R39, R40, R42, diode D14, and diode D15 form a drive circuit to provide PWM control drive signals for the gate of MOSFET tube Q5.

[0060] Resistors R18, R19, R20, R21, R22, R23, R24, R25, R26, R27, R28, R29, diode D8, diode D11, transistor Q3, transistor Q4, transformer T2 secondary winding T2-6, T2-7, T2-9, T2-10 form the gate drive circuit of MOSFET tube Q1 and MOSFET tube Q2. When MOSFET tube Q1 and MOSFET tube Q2 are turned off, the gate charge is quickly discharged through the conduction of transistor Q3 and transistor Q4, and the shutdown is more sufficient and fast, thereby reducing the internal loss of the main power MOSFET tube. The circuit composed of other components makes the parameters of the drive circuit match the performance indicators such as the forward switching time and input impedance of the main power MOSFET tube, so as to achieve a more efficient switching working state of the MOSFET tube and improve the working efficiency of the DC-DC conversion circuit. Transformer T2 plays the role of driving transformer isolation.

[0061] The G pole of the MOSFET tube Q1 in the DC-DC conversion circuit is connected to the driving circuit one, the G pole of the MOSFET tube Q2 in the DC-DC conversion circuit is connected to the driving circuit two, the D pole of the MOSFET tube Q1 is connected to a diode D3, one end of the diode D3 is connected to the 10th pin of the transformer T1, a diode D2 and a capacitor C3 are connected between the 9th pin and the 10th pin of the transformer T1, the connection terminals of the diode D2 and the capacitor C3 are connected to a series resistor R5 and a resistor R6, and a series resistor R7 and a resistor R8, and the connection terminals of the resistor R5 and the resistor R7 are connected to the diode D1.

[0062] The DC-DC conversion circuit also includes a transformer CT1, wherein the pin 1 of the transformer CT1 is connected to resistors R11, R12 and R13 which are arranged in parallel via resistors R30 and R31 which are arranged in series with the pin 3 of the transformer CT1, wherein one terminal of the resistors R11, R12 and R13 is connected to the S pole of the MOSFET tube Q1, and the other terminals of the resistors R11, R12 and R13 are connected to the pin 2 of the transformer T1, and a diode D10 is connected between the D pole of the MOSFET tube Q2 and the pin 1 of the transformer T1;

[0063] The resistor R29 is connected between the G pole and the S pole of the MOSFET tube Q2, the S pole of the MOSFET tube Q2 is connected to the 6th pin of the transformer CT1, the capacitor C29 and the diode D9 are connected between the 1st pin and the 2nd pin of the transformer T1, the capacitor C29 is connected in parallel with the series resistor R14 and the resistor R15, the resistor R14 and the resistor R15 are connected in parallel with the series resistor R16 and the resistor R17, the 4th pin of the transformer CT1 is respectively connected with the diode D12 and the series capacitor C2 and the capacitor C1, and one end of the capacitor C1 is connected to the diode D1.

[0064] The diode D16 is connected to the 12th pin of the transformer T1, the diode D17 is connected to the 4th pin of the transformer T1, the diode D18 is connected to the 5th pin of the transformer T1, the RC absorption circuit includes a resistor R43, a resistor R44 and a capacitor C18 connected in parallel to the diode D16, a resistor R45 and a capacitor C23 connected in parallel to the diode D17, a resistor R47 and a capacitor C26 connected in parallel to the diode D18, the secondary DC power supply LC filter circuit includes a capacitor C19, a capacitor C20, a capacitor C21, and a capacitor C22 connected in parallel between the 11th pin of the transformer T1 and one end of the diode D16, the two ends of the capacitor C22 are respectively connected to an inductor L1 and an inductor L2, and the primary DC power supply filter circuit includes a capacitor C24 and a capacitor C25 connected in parallel between the 3rd pin of the transformer T1 and the 4th pin of one end of the diode D17, and a capacitor C27 and a capacitor C28 connected in parallel between the 3rd pin of the transformer T1 and one end of the diode D18.

[0065] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An 800V high voltage input 15V DC power supply circuit, characterized in that: It includes an input rectifying and filtering circuit whose input end is connected to 800V input high-voltage direct current, a DC-DC conversion circuit, an output rectifying and filtering circuit whose output end can output multiple 15V direct currents, a PWM signal control driving circuit, and a transformer T1. The input rectifying and filtering circuit, the DC-DC conversion circuit, and the output rectifying and filtering circuit are connected in sequence, the DC-DC conversion circuit is connected to the PWM signal control driving circuit, and the DC-DC conversion circuit, the output rectifying and filtering circuit, and the PWM signal control driving circuit are all connected to the transformer T1; The input rectification and filtering circuit includes a diode D1 for rectifying the input DC high voltage signal, a capacitor C1 and a capacitor C2 connected in series for input filtering; The main components of the DC-DC conversion circuit include a MOSFET tube Q1 and a MOSFET tube Q2 arranged in series, the MOSFET tubes Q1 and Q2 are connected to an absorption circuit capable of absorbing reverse electric energy generated by flyback DC-DC conversion, and the MOSFET tubes Q1 and Q2 are connected to a main circuit current detection circuit; The output rectification and filtering circuit comprises an output rectification loop composed of a diode D16, a diode D17 and a diode D18, an RC absorption circuit is connected in parallel to the output rectification loop, and one end of the output rectification loop is connected to a DC power supply output filtering circuit.

2. The 800V high voltage input 15V DC power supply circuit according to claim 1, characterized in that: The PWM signal control driving circuit includes a PWM control chip U1 for controlling the operation of the MOSFET tube Q1 and the MOSFET tube Q2. The pin 7 of the PWM control chip U1 is connected in series with resistors R1, R2, R3 and R4.

3. The 800V high voltage input 15V DC power supply circuit according to claim 2, characterized in that: The PWM signal control driving circuit also includes a transformer T2 and a MOSFET tube Q5. Pin 1 of the transformer T2 is connected to pin 7 of the PWM control chip U1. Pin 2 of the transformer T2 is connected to a diode D7. A Zener diode ZD1, a capacitor C5, a capacitor C6 and a capacitor C7 arranged in parallel are connected between the diode D7 and pin 7 of the PWM control chip U1. A diode D6, a resistor R9 and a capacitor C8 are connected in series between the two ends of the capacitor C7. One end of the capacitor C8 is connected to pin 7 of the transformer T1, and a diode D5, a diode D4, a capacitor C4 and a resistor R10 arranged in parallel are connected between the other end of the capacitor C8 and pin 8 of the transformer T1.

4. The 800V high voltage input 15V DC power supply circuit according to claim 3, characterized in that: The transformer T2 is connected with a driving circuit 1 for driving the MOSFET tube Q1 and a driving circuit 2 for driving the MOSFET tube Q2. The main component of the driving circuit 1 includes a transistor Q3, and the main component of the driving circuit 2 includes a transistor Q4.

5. The 800V high voltage input 15V DC power supply circuit according to claim 4, characterized in that: The D pole of the MOSFET tube Q5 is connected to the 5th pin of the transformer T2, a capacitor C17 is connected between the S pole of the MOSFET tube Q5 and the 4th pin of the transformer T2, a resistor R42 is connected between the G pole and the S pole of the MOSFET tube Q5, a resistor R40 is connected between the G pole of the MOSFET tube Q5 and the 6th pin of the PWM control chip U1, and a resistor R39 and a diode D15 are connected in series in parallel to the resistor R40.

6. The 800V high voltage input 15V DC power supply circuit according to claim 5, characterized in that: The G pole of the MOSFET tube Q1 in the DC-DC conversion circuit is connected to the driving circuit one, the G pole of the MOSFET tube Q2 in the DC-DC conversion circuit is connected to the driving circuit two, the D pole of the MOSFET tube Q1 is connected to a diode D3, one end of the diode D3 is connected to the 10th pin of the transformer T1, a diode D2 and a capacitor C3 are connected between the 9th pin and the 10th pin of the transformer T1, the connection terminals of the diode D2 and the capacitor C3 are connected to a series resistor R5 and a resistor R6, and a series resistor R7 and a resistor R8, and the connection terminals of the resistor R5 and the resistor R7 are connected to the diode D1.

7. The 800V high voltage input 15V DC power supply circuit according to claim 6, characterized in that: The DC-DC conversion circuit also includes a transformer CT1, wherein the pin 1 of the transformer CT1 is connected to resistors R11, R12 and R13 which are arranged in parallel via resistors R30 and R31 which are arranged in series with the pin 3 of the transformer CT1, wherein one terminal of the resistors R11, R12 and R13 is connected to the S pole of the MOSFET tube Q1, and the other terminals of the resistors R11, R12 and R13 are connected to the pin 2 of the transformer T1, and a diode D10 is connected between the D pole of the MOSFET tube Q2 and the pin 1 of the transformer T1; The S pole of the MOSFET tube Q2 is connected to the 6th pin of the transformer CT1, and a capacitor C29 and a diode D9 are connected between the 1st pin and the 2nd pin of the transformer T1. The capacitor C29 is connected in parallel with a resistor R14 and a resistor R15 connected in series, and the resistor R14 and the resistor R15 are connected in parallel with a resistor R16 and a resistor R17 connected in series. The 4th pin of the transformer CT1 is respectively connected with a diode D12 and a capacitor C2 and a capacitor C1 connected in series.

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