Switching power supply high voltage power supply circuit and device

Abstract

The embodiment of the application provides a switching power supply high-voltage power supply circuit and device, comprising: a rectifier circuit, a first diode, a second diode, a chip, a first resistor R HV , the chip comprises a VDD pin, an HV pin and a switch tube, the first input end of the rectifier circuit is connected with the anode of the first diode, the second input end of the rectifier circuit is connected with the anode of the second diode, the cathode of the first diode and the cathode of the second diode are connected with one end of the first resistor R HV , the other end of the first resistor R HV is connected with the HV pin, the HV pin is connected with the first pole of the switch tube, the second pole of the switch tube is connected with the VDD pin. When the voltage U HV is less than or equal to a preset boundary value, the switch tube is turned on, and the circuit carries out high-voltage power supply; when the voltage U HV is greater than the preset boundary value, the switch tube is turned off, and the circuit stops high-voltage power supply. The scheme can avoid the pin overvoltage risk in the high output voltage, and reduce the cost of circuit design.

Description

Technical Field

[0001] This application relates to the field of electronic technology, and in particular to a high-voltage power supply circuit and device for a switching power supply. Background Technology

[0002] Universal Serial Bus (USB) technology is one of the most widely used communication interfaces in modern life. Besides its fast data transfer capabilities, USB also provides a reliable power connection for its compatible devices. Most electronic devices can now be charged using USB chargers, and with technological advancements, charging speeds are becoming increasingly faster. USB chargers use switching power supply technology to convert AC mains power into the charging voltage required by the electronic device, typically employing a flyback converter topology. The primary-side control chip requires a certain operating voltage to function properly, which is generally provided by the primary-side high voltage or the auxiliary winding of the transformer.

[0003] However, on the one hand, high-voltage power supply requires series resistors, and long-term power supply will increase overall losses; on the other hand, as the power demand increases, that is, the output voltage increases, the voltage on the auxiliary winding will also increase, and the power supply by the auxiliary winding is difficult to meet the voltage withstand requirements of the chip pins when the output voltage is high. Summary of the Invention

[0004] This application provides a high-voltage power supply circuit and device for a switching power supply, which can reduce power loss during high-voltage power supply and reduce the cost of circuit design.

[0005] In a first aspect, embodiments of this application provide a high-voltage power supply circuit for a switching power supply, the circuit including a rectifier circuit, a first diode, a second diode, a chip, and a first resistor R. HV The chip includes a power supply voltage input VDD pin, a high voltage input HV pin, and a switching transistor. The first input terminal of the rectifier circuit is connected to the anode of the first diode, and the second input terminal of the rectifier circuit is connected to the anode of the second diode. The cathodes of the first diode and the second diode are connected to the first resistor R. HV One end is connected, the first resistor R HV The other end is connected to the HV pin, the HV pin is connected to the first terminal of the switching transistor, and the second terminal of the switching transistor is connected to the VDD pin.

[0006] In this embodiment, the chip and the entire switching power supply are driven to work by detecting the voltage value of the power supply voltage input VDD pin. The switching transistor is turned on or off by comparing the voltage value of the high voltage input HV pin with a constant boundary value, thereby achieving a stable high voltage power supply for the switching power supply and reducing power loss during high voltage power supply.

[0007] In one possible design, the circuit further includes a first capacitor C. VDD Wherein, the VDD pin is connected to the first capacitor C VDD One end is connected, the first capacitor C VDD The other end is grounded.

[0008] In one possible design, the circuit further includes a second resistor R. a1 Third resistor R a2 In addition to the auxiliary winding AUX, the chip also includes a detection VS pin and a ground GND pin, wherein the VS pin is connected to the second resistor R. a1 one end and the third resistor R a2 One end is connected, and the second resistor R a1 The other end is connected to the same-name terminal of the auxiliary winding AUX, and the opposite-name terminal of the auxiliary winding AUX is grounded. The third resistor R a2 The other end is grounded, and the GND pin is grounded.

[0009] In one possible design, the circuit also includes a fourth resistor R. cs Switch, transformer, second capacitor C in Third diode D1, third capacitor C out The chip also includes a sampling signal CS pin and a power transistor GATE pin, wherein the output terminal of the rectifier circuit is connected to the second capacitor C. in One end of the switch is connected to the primary non-nominal terminal of the transformer, the primary same-nominal terminal of the transformer is connected to the first terminal of the switch, the second terminal of the switch is connected to the GATE pin, and the third terminal of the switch is connected to the CS pin and the fourth resistor R. cs One end is connected to the fourth resistor R. cs The other end is grounded, and the second capacitor C in The other end is grounded, the secondary winding terminal of the transformer is connected to the positive terminal of the third diode D1, and the negative terminal of the third diode D1 is connected to the third capacitor C. out One end and output voltage U out The transformer's secondary winding terminal is connected to the third capacitor C. out The other end is grounded.

[0010] In one possible design, the rectifier circuit includes a fourth diode, a fifth diode, a sixth diode, and a seventh diode. The first input terminal of the rectifier circuit is connected to the anode of the fourth diode and the cathode of the fifth diode. The second input terminal of the rectifier circuit is connected to the anode of the sixth diode and the cathode of the seventh diode. The cathodes of the fourth diode and the sixth diode are connected to the output terminal of the rectifier circuit. The anodes of the fifth diode and the seventh diode are grounded.

[0011] In the embodiments of this application, the first input terminal of the rectifier circuit is connected to the input terminal of the AC circuit. The unidirectional conductivity of the diode is used to make the current in the circuit flow in only one direction. In each working cycle of the rectifier circuit, only two diodes (the fourth diode and the seventh diode, or the fifth diode and the sixth diode) work at the same time, so that the output terminal of the rectifier circuit receives DC power.

[0012] In one possible design, the circuit also includes a fifth resistor C. FB In addition to the phototransistor, the chip also includes a current feedback input FB pin, which is connected to the fifth resistor C. FB One end of the resistor is connected to the collector of the phototransistor, and the fifth resistor C is connected to the collector of the phototransistor. FB The other end is grounded, as is the emitter of the phototransistor.

[0013] In one possible design, the circuit also includes a sixth resistor R. H The seventh resistor R b1 The eighth resistor R b2 Photodiode, Ninth resistor R1, Fourth capacitor C1, Tenth resistor R L and a Zener diode, wherein the seventh resistor R b1 One end is connected to the sixth resistor R H one end and the third capacitor C out One end is connected to the seventh resistor R. b1 The other end is connected to the positive terminal of the photodiode and the eighth resistor R. b2 One end is connected to the negative terminal of the photodiode and the eighth resistor R. b2 The other end is connected to the negative terminal of the Zener diode and one end of the ninth resistor R1. The other end of the ninth resistor R1 is connected to one end of the fourth capacitor C1. The other end of the fourth capacitor C1 is connected to the positive terminal of the Zener diode and the tenth resistor R1. L one end and the sixth resistor R H The other end is connected to the tenth resistor R. L The other end is grounded to the positive terminal of the Zener diode.

[0014] In one possible design, the switching transistor is a high-voltage switching transistor.

[0015] Secondly, embodiments of this application provide a power supply device, which includes the high-voltage power supply circuit of the switching power supply provided in the first aspect. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the background art, the accompanying drawings used in the embodiments of this application or the background art will be described below.

[0017] Figure 1 This is a schematic diagram of the structure of a high-voltage power supply circuit for a switching power supply provided in an embodiment of this application;

[0018] Figure 2 This is a schematic diagram of the structure of a high-voltage power supply circuit for a switching power supply provided in an embodiment of this application;

[0019] Figure 3 This is a schematic diagram of the structure of a high-voltage power supply circuit for a switching power supply provided in an embodiment of this application;

[0020] Figure 4 This is a schematic diagram of the structure of a high-voltage power supply circuit for a switching power supply provided in an embodiment of this application;

[0021] Figure 5 This is a schematic diagram of a voltage waveform provided in an embodiment of this application. Detailed Implementation

[0022] The embodiments of this application are described below with reference to the accompanying drawings.

[0023] Please see Figure 1 , Figure 1 This is a schematic diagram of a high-voltage power supply circuit for a switching power supply provided in an embodiment of this application. The circuit includes: a rectifier circuit and a first capacitor C. in First resistor R HV1 Second resistor R HV2 And a chip, the chip including a power supply voltage input VDD pin and a high voltage input HV pin, wherein the output terminal of the rectifier circuit is connected to the first capacitor C. in one end and the first resistor R HV1 One end is connected, the first capacitor C in The other end is grounded, and the first resistor R HV1 The other end is connected to the second resistor R HV2 One end is connected, and the second resistor R HV2 The other end is connected to the HV pin, which is connected to the VDD pin.

[0024] Furthermore, the high-voltage power supply circuit of the switching power supply also includes a second capacitor C. VDD First diode D2, third resistor R a1 Fourth resistor R a2 The chip also includes an auxiliary winding AUX and a VS detection pin, wherein the VDD pin is connected to the second capacitor C. VDD One end of the capacitor is connected to the negative terminal of the first diode D2, and the second capacitor C is connected to the negative terminal of the first diode D2. VDD The other end is grounded, and the positive terminal of the first diode D2 is connected to the corresponding terminal of the auxiliary winding AUX and the third resistor R. a1 One end is connected to the third resistor R. a1 The other end is connected to the VS pin and the fourth resistor R. a2 One end is connected to the fourth resistor R. a2 The other end is grounded to the opposite end of the auxiliary winding AUX.

[0025] In such Figure 1 In the circuit structure shown, the power supply voltage input VDD pin and the high voltage input HV pin of the chip are connected by wires. The power supply to the chip in this circuit mainly includes the following two power supply lines: one is through a rectifier circuit, the primary side voltage (the input side of the transformer), and the first resistor R. HV1 Second resistor R HV2 One high-voltage power supply line connects to the HV high-voltage input pin and the VDD power supply input pin. This line is directly connected to AC power and converts the AC power into the power supply voltage for chip operation. The other line connects to the auxiliary winding AUX, the first diode D2, and the second capacitor C. VDD The power supply line is powered by the voltage on the auxiliary winding AUX, which supplies power to the chip.

[0026] Specifically, when starting up or otherwise activating the high-voltage power supply mode, the high-voltage power supply line is connected, and the AC power is converted into DC power by the rectifier circuit, and then passes through the first resistor R in series. HV1 Second resistor R HV2 At that time, due to the limitation of starting speed, the resistance value cannot be too large, in the first resistor R HV1 Second resistor R HV2 This will generate additional power, causing power loss in the entire high-voltage power supply process.

[0027] Furthermore, the high-voltage power supply circuit of the switching power supply also includes a transformer, a switch, and a fifth resistor R. cs Second diode D1, third capacitor C out The chip also includes a sampling signal CS pin and a power transistor GATE pin, wherein the first resistor R HV1One end of the switch is connected to the primary winding of the transformer (opposite-named terminal), the primary winding of the transformer (same-named terminal) is connected to the first terminal of the switch, the second terminal of the switch is connected to the GATE pin, and the third terminal of the switch is connected to the CS pin and the fifth resistor R. cs One end is connected to the fifth resistor R. cs The other end is grounded, the secondary winding terminal of the transformer is connected to the positive terminal of the second diode D1, and the negative terminal of the second diode D1 is connected to the third capacitor C. out One end and output voltage U out The transformer's secondary winding terminal is connected to the third capacitor C. out The other end is grounded.

[0028] Specifically, during normal operation, the GATE pin drives the switch. At this time, the coil on the primary side of the circuit consists of the primary coil of the transformer and the coil of the auxiliary winding AUX, while the coil on the secondary side of the circuit is the secondary coil of the transformer. When the switch is turned off, the voltage U on the auxiliary winding AUX... AUX With output voltage U out This exhibits a multiple relationship, ensuring that under high output voltage conditions, the voltage U on the chip's supply voltage input VDD pin is [value missing]. VDD If the value is too high, it may exceed the pin's standard withstand voltage value, thereby damaging the chip.

[0029] Please see Figure 2 , Figure 2 This is a schematic diagram of a high-voltage power supply circuit for a switching power supply according to an embodiment of this application. The circuit includes: a rectifier circuit, a first diode, a second diode, a chip, and a first resistor R. HV1 The chip includes a power supply voltage input VDD pin, a high voltage input HV pin, a switching transistor, and a second resistor R. HV2 The third diode D3, wherein the first input terminal of the rectifier circuit is connected to the anode of the first diode, the second input terminal of the rectifier circuit is connected to the anode of the second diode, and the cathodes of the first diode and the second diode are connected to the first resistor R. HV1 One end is connected, the first resistor R HV1 The other end is connected to the HV pin, which is connected to the first terminal of the switching transistor. The second terminal of the switching transistor is connected to the anode of the third diode D3, and the cathode of the third diode D3 is connected to the second resistor R. HV2 One end is connected, and the second resistor R HV2 The other end is connected to the VDD pin.

[0030] Furthermore, the high-voltage power supply circuit of the switching power supply also includes a first capacitor C. VDDFourth diode D2, third resistor R a1 Fourth resistor R a2 The chip also includes an auxiliary winding AUX and a VS detection pin, wherein the VDD pin is connected to the first capacitor C. VDD One end of the capacitor is connected to the negative terminal of the fourth diode D2, and the first capacitor C is connected to the negative terminal of the fourth diode D2. VDD The other end is grounded, and the positive terminal of the fourth diode D2 is connected to the corresponding terminal of the auxiliary winding AUX and the third resistor R. a1 One end is connected to the third resistor R. a1 The other end is connected to the VS pin and the fourth resistor R. a2 One end is connected to the fourth resistor R. a2 The other end is grounded to the opposite end of the auxiliary winding AUX.

[0031] In such Figure 2 In the circuit structure shown, with Figure 1 Compared to the circuit structure described above, this circuit adds a first diode and a second diode, and connects the two diodes as rectifier diodes to the first and second input terminals of the rectifier circuit (i.e., the first and second input terminals of the AC power supply), respectively. The first resistor R is connected in series... HV1 Second resistor R HV2 Change to only the first resistor R HV1 Connect the HV pin and connect the second resistor R HV2 The third diode D3 and the switching transistor are connected between the high-voltage input HV pin and the power supply voltage input VDD pin inside the chip. The switching transistor is a high-voltage switching transistor. The circuit mainly supplies power to the chip through the following two power supply lines: one through rectifier diodes (first and second diodes) and the first resistor R. HV1 High-voltage input HV pin, switching transistor, third diode D3, second resistor R HV2 One is the high-voltage power supply line input to the VDD pin, which is directly connected to AC power and converts the AC power into the power supply voltage for chip operation; the other is from the auxiliary winding AUX, the fourth diode D2 to the first capacitor C. VDD The power supply line is powered by the voltage on the auxiliary winding AUX. High voltage power supply is the main power supply method for the chip, and the connection and disconnection of the high voltage power supply line are controlled by the switching transistor.

[0032] Specifically, under high-voltage power supply, the switching transistor is in the connected state, and the AC power flows through the high-voltage power supply line to the VDD pin, where the voltage U is... VDDOnce the preset voltage value is reached, the startup chip and the entire switching power supply begin normal operation. During normal operation, AC power flows through the rectifier diodes (first diode and second diode) and the first resistor R in the high-voltage power supply line. HV1 Reach the HV pin and detect the voltage U on the HV pin. HV When voltage U HV Less than voltage U VDD At boundary values, it is determined to be voltage U. HV In the valley region, the connected switch is charged with high voltage; when the voltage U HV Greater than voltage U VDD At boundary values, the switching transistor is disconnected to stop power supply. Additionally, when the voltage U on the auxiliary winding... AUX Greater than voltage U VDD When necessary, the high-voltage power supply line can be shut off, and power can be supplied only by the auxiliary winding AUX.

[0033] At voltage U HV When charging in the valley region, the voltage U VDD With voltage U HV The increase in voltage U is fluctuating. Since the amount of charge in each cycle is uncertain, it is necessary to set the voltage U. VDD upper and lower boundary values ​​(U) top U bottom ), making voltage U VDD Located between the upper and lower boundary values, to avoid voltage U VDD This exceeds the normal operating voltage range. Furthermore, to ensure sufficient charging in each cycle, it is necessary to adjust the voltage U during chip operation. VDD The dynamic value is adjusted at the upper and lower boundary values, but the voltage U VDD The design and dynamic adjustment of the upper and lower boundary values ​​and their corresponding logic decision circuits increase the complexity and cost of chip design.

[0034] Therefore, based on the problems existing in the prior art, the present application provides a high-voltage power supply circuit and device for a switching power supply, which can reduce the additional power loss caused by high-voltage power supply and the overvoltage risk of auxiliary winding power supply, while reducing the design cost caused by additional components and logic determination circuits.

[0035] Please see Figure 3 , Figure 3 This is a schematic diagram of a high-voltage power supply circuit for a switching power supply according to an embodiment of this application. The circuit includes: a rectifier circuit, a first diode, a second diode, a chip, and a first resistor R. HVThe chip includes a power supply voltage input VDD pin, a high voltage input HV pin, and a switching transistor. The first input terminal of the rectifier circuit is connected to the anode of the first diode, and the second input terminal of the rectifier circuit is connected to the anode of the second diode. The cathodes of the first diode and the second diode are connected to the first resistor R. HV One end is connected, the first resistor R HV The other end is connected to the HV pin, the HV pin is connected to the first terminal of the switching transistor, and the second terminal of the switching transistor is connected to the VDD pin.

[0036] In such Figure 3 In the circuit structure shown, the power supply voltage input VDD pin and the high voltage input HV pin of the chip are connected through a switching transistor. This switching transistor can be a high-voltage switching transistor, and the first and second diodes can be rectifier diodes. The resulting rectifier circuit is connected to the first and second input terminals of the rectifier circuit, respectively, converting AC power to DC power. The chip's power supply line in this circuit mainly consists of the rectifier diodes (first and second diodes) and the first resistor R. HV The high-voltage power supply lines for the HV pin, switching transistor, and VDD pin are as follows: the input terminals of the rectifier diodes (the anodes of the first and second diodes) are connected to the AC power input of the switching power supply, and the output terminals of the rectifier diodes (the cathodes of the first and second diodes) are connected to the first resistor R. HV One end, the first resistor R HV The other end is connected to the HV pin of the chip. Inside the chip, the drain (first terminal) of the high-voltage switching transistor is connected to the HV pin, and the source (second terminal) is connected to the VDD pin.

[0037] For further details, please see Figure 4 , Figure 4 This is a schematic diagram of a high-voltage power supply circuit for a switching power supply provided in an embodiment of this application. Figure 4 The circuit also includes a first capacitor C. VDD Wherein, the VDD pin is connected to the first capacitor C VDD One end is connected, the first capacitor C VDD The other end is grounded.

[0038] It should be understood that the power supply method of the high-voltage power supply circuit of this switching power supply includes, but is not limited to, the following two processes:

[0039] 1. When the circuit is powered on, the high-voltage switching transistor inside the chip remains on, and the current flows continuously to the first capacitor C through the high-voltage power supply line. VDD The voltage U at the VDD pin VDD The voltage U continues to rise. VDD Value, when voltage UVDD The value is less than the preset boundary value U boundary (boundary value U) boundary When the voltage U is constant, other parts of the chip do not work, and there is no drive voltage output at the GATE pin of the chip's power transistor; when the voltage U... VDD The value is greater than or equal to the preset boundary value U. boundary At that time, the chip and the entire switching power supply begin to work normally.

[0040] 2. During normal operation, the voltage U at the HV pin of the detection chip is measured. HV The value is used to determine whether the high-voltage switching transistor is turned on for high-voltage charging. Assuming that initially the high-voltage switching transistor is in the off state, the voltage U at the rectifier output terminal is... rec Value and voltage U at HV pin HV When the values ​​are the same, when the voltage U HV The value is less than the preset boundary value U boundary When the chip drives the high-voltage switch to conduct, it performs high-voltage charging. After the high-voltage switch is turned on, because the chip's HV pin is directly connected to the VDD pin, the voltage U at the HV pin is... HV The value will quickly drop to the voltage U at the VDD pin. VDD The values ​​are equal, at this time the voltage U rec Value and voltage U HV Value (voltage U) VDD The value deviation is small, and the subsequent voltage U rec The value will drop rapidly to 0V, resulting in a very short charging time, therefore the voltage U rec The charging during the value decrease phase is negligible, and due to the limitation of the rectifier diode, the first capacitor C... VDD It will not discharge in reverse to the AC power source.

[0041] Next, voltage U rec The value begins to rise and reaches voltage U. HV Value (voltage U) VDD (value), because the first resistor R HV The resistance is small, and the voltage U HV Value (voltage U) VDD The value will change with voltage U rec The value rapidly rises to the preset boundary value U boundary This completes the high-voltage charging process.

[0042] When voltage U HV The value is greater than the preset boundary value U boundary When the chip drives the high-voltage switching transistor to disconnect, the high-voltage power supply is stopped. At this time, the voltage U HV Value and voltage U VDD The value no longer changes synchronously, voltage U HV The value will continue to increase with voltage Urec Value change, voltage U VDD The value decreases slowly to maintain chip operation. The specific process is as follows: Figure 5 As shown, Figure 5 This is a voltage waveform diagram provided in an embodiment of this application, where the main charging process occurs at voltage U. rec During the period t1-t2, when the value is rising.

[0043] Optionally, the circuit further includes a second resistor R. a1 Third resistor R a2 In addition to the auxiliary winding AUX, the chip also includes a detection VS pin and a ground GND pin, wherein the VS pin is connected to the second resistor R. a1 one end and the third resistor R a2 One end is connected, and the second resistor R a1 The other end is connected to the same-name terminal of the auxiliary winding AUX, and the opposite-name terminal of the auxiliary winding AUX is grounded. The third resistor R a2 The other end is grounded, and the GND pin is grounded.

[0044] Optionally, the circuit further includes a fourth resistor R. cs Switch, transformer, second capacitor C in Third diode D1, third capacitor C out The chip also includes a sampling signal CS pin and a power transistor GATE pin, wherein the output terminal of the rectifier circuit is connected to the second capacitor C. in One end of the switch is connected to the primary non-nominal terminal of the transformer, the primary same-nominal terminal of the transformer is connected to the first terminal of the switch, the second terminal of the switch is connected to the GATE pin, and the third terminal of the switch is connected to the CS pin and the fourth resistor R. cs One end is connected to the fourth resistor R. cs The other end is grounded, and the second capacitor C in The other end is grounded, the secondary winding terminal of the transformer is connected to the positive terminal of the third diode D1, and the negative terminal of the third diode D1 is connected to the third capacitor C. out One end and output voltage U out The transformer's secondary winding terminal is connected to the third capacitor C. out The other end is grounded.

[0045] Optionally, the rectifier circuit includes a fourth diode, a fifth diode, a sixth diode, and a seventh diode. The first input terminal of the rectifier circuit is connected to the anode of the fourth diode and the cathode of the fifth diode. The second input terminal of the rectifier circuit is connected to the anode of the sixth diode and the cathode of the seventh diode. The cathodes of the fourth diode and the sixth diode are connected to the output terminal of the rectifier circuit. The anodes of the fifth diode and the seventh diode are grounded.

[0046] Optionally, the circuit further includes a fifth resistor C. FB In addition to the phototransistor, the chip also includes a current feedback input FB pin, which is connected to the fifth resistor C. FB One end of the resistor is connected to the collector of the phototransistor, and the fifth resistor C is connected to the collector of the phototransistor. FB The other end is grounded, as is the emitter of the phototransistor.

[0047] Optionally, the circuit further includes a sixth resistor R. H The seventh resistor R b1 The eighth resistor R b2 Photodiode, Ninth resistor R1, Fourth capacitor C1, Tenth resistor R L and a Zener diode, wherein the seventh resistor R b1 One end is connected to the sixth resistor R H one end and the third capacitor C out One end is connected to the seventh resistor R. b1 The other end is connected to the positive terminal of the photodiode and the eighth resistor R. b2 One end is connected to the negative terminal of the photodiode and the eighth resistor R. b2 The other end is connected to the negative terminal of the Zener diode and one end of the ninth resistor R1. The other end of the ninth resistor R1 is connected to one end of the fourth capacitor C1. The other end of the fourth capacitor C1 is connected to the positive terminal of the Zener diode and the tenth resistor R1. L one end and the sixth resistor R H The other end is connected to the tenth resistor R. L The other end is grounded to the positive terminal of the Zener diode.

[0048] Optionally, the switching transistor is a high-voltage switching transistor.

[0049] In this embodiment of the application, charging in each cycle is performed at voltage U HV Value (voltage U) VDD The value rises to the preset boundary value U. boundary The charging cycle ends when the voltage U is ensured.VDD The value reaches the required voltage value (U) boundary Therefore, during normal operation, the voltage U VDD The value can always remain stable at the preset boundary value U. boundary Below, the price action remains relatively stable.

[0050] This application embodiment also provides a power supply device, the device comprising the components described above. Figures 1-3 The high-voltage power supply circuit of any of the switching power supplies described herein.

[0051] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A switching power supply high voltage power supply circuit, characterized by comprising: The circuit comprises a rectifier circuit, a first diode, a second diode, a chip, a first resistor R HV , the chip comprises a power supply voltage input VDD pin, a high voltage input HV pin and a switch tube, wherein the first input end of the rectifier circuit is connected with the positive electrode of the first diode, the second input end of the rectifier circuit is connected with the positive electrode of the second diode, the negative electrode of the first diode and the negative electrode of the second diode are connected with one end of the first resistor R HV , the other end of the first resistor R HV is connected with the HV pin, the HV pin is connected with the first pole of the switch tube, and the second pole of the switch tube is connected with the VDD pin. The circuit also includes a first capacitor C. VDD Wherein, the VDD pin is connected to the first capacitor C VDD One end is connected, the first capacitor C VDD The other end is grounded; the circuit also includes a second resistor R. a1 Third resistor R a2 In addition to the auxiliary winding AUX, the chip also includes a detection VS pin and a ground GND pin, wherein the VS pin is connected to the second resistor R. a1 one end and the third resistor R a2 One end is connected, and the second resistor R a1 The other end is connected to the same-name terminal of the auxiliary winding AUX, and the opposite-name terminal of the auxiliary winding AUX is grounded. The third resistor R a2 The other end is grounded, and the GND pin is grounded; said first capacitor C VDD one end of which is not connected through a diode to the like-named end of said auxiliary winding AUX; When the voltage U at the HV pin of the chip HV When the value is less than or equal to a preset boundary value, the switch is turned on, and the circuit receives high-voltage power; and / or When the voltage U at the HV pin of the chip HV When the value exceeds the preset boundary value, the switch is turned off, and the circuit stops supplying high voltage power.

2. The circuit of claim 1, wherein, When the chip is powered on, if the voltage U at the VDD pin of the chip is greater than the preset boundary value VDD greater than or equal to the preset boundary value, the chip starts to work.

3. The circuit of claim 1, wherein, The circuit further comprises a fourth resistor R cs , a switch, a transformer, a second capacitor C in , a third diode D1, a third capacitor C out , and the chip further comprises a sampling signal CS pin and a power tube GATE pin, wherein an output end of the rectifier circuit is connected with one end of the second capacitor C in and a primary opposite-phase end of the transformer, a primary same-phase end of the transformer is connected with a first pole of the switch, a second pole of the switch is connected with the GATE pin, a third pole of the switch is connected with the CS pin and one end of the fourth resistor R cs , the other end of the fourth resistor R cs is grounded, the other end of the second capacitor C in is grounded, a secondary same-phase end of the transformer is connected with a positive pole of the third diode D1, a negative pole of the third diode D1 is connected with one end of the third capacitor C out and an output voltage U out , and a secondary opposite-phase end of the transformer is grounded with the other end of the third capacitor C out .

4. The circuit of claim 1, wherein, The rectifier circuit comprises a fourth diode, a fifth diode, a sixth diode and a seventh diode, wherein the first input end of the rectifier circuit is connected with the positive electrode of the fourth diode and the negative electrode of the fifth diode, the second input end of the rectifier circuit is connected with the positive electrode of the sixth diode and the negative electrode of the seventh diode, the negative electrode of the fourth diode and the negative electrode of the sixth diode are connected with the output end of the rectifier circuit, and the positive electrode of the fifth diode and the positive electrode of the seventh diode are grounded.

5. The circuit of claim 3, wherein, The circuit further comprises a fifth resistor C FB and a phototransistor, the chip further comprising a current feedback input FB pin connected to one end of the fifth resistor C FB and to the collector of the phototransistor, the other end of the fifth resistor C FB being grounded and the emitter of the phototransistor.

6. The circuit of claim 5, wherein, The circuit further comprises a sixth resistor R H , a seventh resistor R b1 , an eighth resistor R b2 , a photosensitive diode, a ninth resistor R1, a fourth capacitor C1, a tenth resistor R L and a voltage stabilizing diode, wherein one end of the seventh resistor R b1 is connected with one end of the sixth resistor R H and one end of the third capacitor C out , the other end of the seventh resistor R b1 is connected with the positive electrode of the photosensitive diode and one end of the eighth resistor R b2 , the negative electrode of the photosensitive diode and the other end of the eighth resistor R b2 are connected with the negative electrode of the voltage stabilizing diode and one end of the ninth resistor R1, the other end of the ninth resistor R1 is connected with one end of the fourth capacitor C1, the other end of the fourth capacitor C1 is connected with the positive electrode of the voltage stabilizing diode, one end of the tenth resistor R L and the other end of the sixth resistor R H respectively, the other end of the tenth resistor R L is grounded with the positive electrode of the voltage stabilizing diode.

7. The circuit according to any one of claims 1 to 6, characterized in that The switch tube is a high-voltage switch tube.

8. A power supply device characterized by comprising: The device comprises the circuit according to any one of claims 1-7.

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