Power supply circuit of PFC circuit and control chip thereof, and electronic equipment

Abstract

The invention discloses a PFC circuit, a power supply circuit of a control chip of the PFC circuit, and electronic equipment, and the power supply circuit comprises an energy storage circuit which is connected with the input end of the PFC circuit and the power supply end of the control chip, and is used for generating a starting voltage based on the input voltage of the PFC circuit to start the control chip to work, the control chip controls the switch tube to be switched on or switched off; the charging and discharging circuit is connected with the energy storage circuit, the charging and discharging circuit comprises a secondary winding of a coupling inductor, and the charging and discharging circuit is used for charging based on the electric energy of the primary winding when the control chip controls the switch tube to be switched on and discharging so as to supplement the electric energy to the energy storage circuit when the control chip controls the switch tube to be switched off; therefore, the working voltage of the control chip is in a preset voltage range. The power supply circuit can stably supply power to the control chip, and is relatively simple in circuit structure, low in hardware cost and high in reliability.

Description

[0001] Related Applications

[0002] The present invention claims the priority of the Chinese invention patent with patent application number 202410852695.X, application date June 27, 2024, and invention name “Power supply circuit and electronic device of PFC circuit and its control chip”. Technical Field

[0003] The present invention relates to the field of electronic circuits, and in particular to a PFC circuit and a power supply circuit of a control chip thereof, and electronic equipment. Background Art

[0004] In electronic circuits, PFC circuits (Power Factor Correction) circuits can effectively improve the power factor of the circuit, so they are widely used. In PFC (Power Factor Correction) circuits, since the power factor correction effect of active PFC circuits is better, they are widely used in many high-performance power supply systems and electronic devices. Usually, active PFC circuits need to set up a main control chip to control the internal power devices, so it is also necessary to set up a power supply circuit for the main control chip in the circuit. In this regard, the PFC circuit in the current related technology usually chooses to add an auxiliary winding to the secondary side of the main transformer of the electronic device, and sets a rectifier and filter circuit at the rear end of the auxiliary winding to power the main control chip. However, the related technology has high requirements for the design of the transformer, which increases the process difficulty of the transformer in terms of process, thereby increasing the hardware cost of the electronic device. Summary of the invention

[0005] The present invention aims to solve one of the technical problems in the related art to at least a certain extent. To this end, the first object of the present invention is to propose a power supply circuit of a PFC circuit control chip, by arranging an energy storage circuit and a charge-discharge circuit in the power supply circuit, wherein the energy storage circuit includes a primary winding of a coupled inductor, and the charge-discharge circuit includes a secondary winding of a coupled inductor, and the charge-discharge circuit can charge based on the electric energy of the primary winding when the control chip controls the switch tube to be turned on, and discharge to replenish electric energy to the energy storage circuit when the control chip controls the switch tube to be turned off, so that the operating voltage of the control chip is within a preset voltage range, thereby realizing stable power supply to the control chip, and the circuit structure is relatively simple, effectively reducing the hardware cost of the power supply circuit, and improving the reliability of the power supply circuit.

[0006] A second objective of the present invention is to provide a PFC circuit.

[0007] A third objective of the present invention is to provide an electronic device.

[0008] To achieve the above-mentioned purpose, an embodiment of a first aspect of the present invention proposes a power supply circuit of a PFC circuit control chip, wherein the PFC circuit comprises a PFC inductor, a switch tube and a control chip, wherein the PFC inductor is a primary winding of a coupled inductor, and the power supply circuit comprises: an energy storage circuit, wherein the energy storage circuit is respectively connected to an input end of the PFC circuit and a power supply end of the control chip, and wherein the energy storage circuit is used to generate a start voltage based on an input voltage of the PFC circuit to start the control chip to operate, so that the control chip controls the switch tube to be turned on or off; and a charge-discharge circuit, wherein the charge-discharge circuit is connected to the energy storage circuit, and wherein the charge-discharge circuit comprises a secondary winding of the coupled inductor, and wherein the charge-discharge circuit is used to charge based on the electric energy of the primary winding when the control chip controls the switch tube to be turned on, and to discharge to replenish electric energy to the energy storage circuit when the control chip controls the switch tube to be turned off, so that the operating voltage of the control chip is within a preset voltage range.

[0009] According to the power supply circuit of the PFC circuit control chip of the embodiment of the present invention, an energy storage circuit and a charge-discharge circuit are arranged in the power supply circuit, wherein the energy storage circuit includes a primary winding of a coupled inductor, and the charge-discharge circuit includes a secondary winding of a coupled inductor. The charge-discharge circuit can be charged based on the electric energy of the primary winding when the control chip controls the switch tube to be turned on, and can be discharged to replenish electric energy for the energy storage circuit when the control chip controls the switch tube to be turned off, so that the operating voltage of the control chip is within a preset voltage range, thereby realizing stable power supply to the control chip, and the circuit structure is relatively simple, which effectively reduces the hardware cost of the power supply circuit and improves the reliability of the power supply circuit.

[0010] According to one embodiment of the present invention, the energy storage circuit includes: a starting resistor, one end of which is connected to the input end of the PFC circuit; a first energy storage capacitor, one end of which is respectively connected to the other end of the starting resistor and the power supply end of the control chip, and the other end of the first energy storage capacitor is grounded.

[0011] According to an embodiment of the present invention, the startup resistor includes a first resistor, or the startup resistor includes a plurality of second resistors connected in series.

[0012] According to one embodiment of the present invention, the charge and discharge circuit also includes: a first diode, a cathode of the first diode being connected to the other end of the starting resistor and one end of the first energy storage capacitor respectively; a second diode, a cathode of the second diode being connected to the anode of the first diode, and the anode of the second diode being grounded; a second energy storage capacitor, one end of the second energy storage capacitor being connected to the anode of the first diode and the cathode of the second diode respectively; a third resistor, one end of the third resistor being connected to the other end of the second energy storage capacitor, the other end of the third resistor being connected to one end of the secondary winding, and the other end of the secondary winding being grounded.

[0013] According to an embodiment of the present invention, the second diode is a voltage regulator.

[0014] According to one embodiment of the present invention, one end of the primary winding is connected to the input end of the PFC circuit, and the other end of the primary winding is connected to the switch tube, wherein one end of the primary winding and the other end of the secondary winding are the same-named ends, and the other end of the primary winding and one end of the secondary winding are the same-named ends.

[0015] According to one embodiment of the present invention, when the control chip controls the switch tube to be turned on, the electric energy of the secondary winding coupled to the primary winding is used to charge the second energy storage capacitor through the second diode; when the control chip controls the switch tube to be turned off, the second energy storage capacitor is discharged through the first diode to supplement the electric energy of the first energy storage capacitor, and the electric energy of the secondary winding coupled to the primary winding is used to supplement the electric energy of the first energy storage capacitor through the first diode.

[0016] To achieve the above-mentioned purpose, a second embodiment of the present invention proposes a PFC circuit, including: a PFC inductor, a switch tube and a control chip, the PFC inductor is a primary winding of a coupled inductor; the aforementioned power supply circuit, the power supply circuit is respectively connected to the input end of the PFC circuit and the power supply end of the control chip, the power supply circuit includes a secondary winding of the coupled inductor, the power supply circuit is used to generate a starting voltage based on the input voltage of the PFC circuit to start the control chip to work, so that the control chip controls the switch tube to be turned on or off, and charges based on the electric energy of the primary winding when the switch tube is turned on, and discharges when the switch tube is turned off, so that the operating voltage of the control chip is within a preset voltage range.

[0017] According to the PFC circuit of the embodiment of the present invention, the aforementioned power supply circuit can realize stable power supply to the control chip in the PFC circuit, and the power supply circuit structure is relatively simple, which effectively reduces the hardware cost of the PFC circuit and improves the reliability of the PFC circuit.

[0018] To achieve the above-mentioned purpose, a third aspect of the present invention provides an electronic device, including the above-mentioned power supply circuit or the above-mentioned PFC circuit.

[0019] According to the electronic device of the embodiment of the present invention, through the aforementioned power supply circuit or the aforementioned PFC circuit, stable power supply to the PFC circuit control chip in the electronic device can be achieved, and the power supply circuit structure is relatively simple, which effectively reduces the hardware cost of the electronic device and improves the reliability of the electronic device.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the structure of a PFC circuit according to an embodiment of the present invention;

[0022] Figure 2 A schematic diagram of the structure of a power supply circuit of a PFC circuit control chip according to an embodiment of the present invention;

[0023] Figure 3 A circuit diagram of an energy storage circuit according to an embodiment of the present invention;

[0024] Figure 4 A circuit diagram of an energy storage circuit according to another embodiment of the present invention;

[0025] Figure 5 is a circuit diagram of a charge and discharge circuit according to an embodiment of the present invention;

[0026] Figure 6 is a waveform diagram of an input voltage of a PFC circuit according to an embodiment of the present invention;

[0027] Figure 7a-7b Schematic diagram of the structure of an electronic device according to some embodiments of the present invention. DETAILED DESCRIPTION

[0028] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0029] The power supply circuit of the PFC circuit control chip, the PFC circuit and the electronic device provided in the embodiments of the present invention are described below with reference to the accompanying drawings.

[0030] It should be noted that the power supply circuit of the embodiment of the present invention can be applied to a variety of PFC circuits with inductors and switch devices. Figure 1 The PFC circuit shown in the figure illustrates a power supply circuit according to an embodiment of the present invention. Figure 1 As shown, the PFC circuit 100 includes a PFC inductor L, a switch tube Q and a control chip 110, wherein the PFC inductor L also serves as a primary winding YZ of a coupled inductor, one end of the PFC inductor L is connected to an input end VIN of the PFC circuit 100, the other end of the PFC inductor L is respectively connected to a first end of the switch tube Q and an output end VOUT of the PFC circuit 100, a second end of the switch tube Q is grounded GND, and a control end of the switch tube Q is connected to the control chip 110.

[0031] Specifically, the PFC inductor L and the switch tube Q constitute a typical active PFC circuit, where the switch tube Q can be a variety of switch tubes, such as MOS tubes, IGBT modules, etc., which are not limited here. Figure 1As shown, the input terminal VIN of the PFC circuit 100 can be connected to the rectifier circuit 300, and the output terminal VOUT of the PFC circuit 100 can be connected to the power conversion circuit 400, and the power conversion circuit 400 can also be connected to the load 500. Among them, the rectifier circuit 300 can be a variety of rectifier circuits, such as a bridge rectifier circuit, etc.; the power conversion circuit 400 can be a variety of circuit topologies, such as an inverter circuit + a rectifier circuit + a DC voltage conversion circuit, etc., which can be specifically set according to the power supply type required by the load 500. In actual operation, the control chip 110 can control the switch tube Q to turn on according to the preset control strategy, so that the phase angle of the input voltage and the input current of the input terminal VIN is as consistent as possible, thereby realizing the power factor correction function of the PFC circuit 100, and the specific principle is not expanded here.

[0032] Figure 2 is a schematic diagram of a power supply circuit according to an embodiment of the present invention, referring to Figure 2 As shown, the power supply circuit 200 includes: an energy storage circuit 210 and a charge and discharge circuit 220 .

[0033] Among them, the energy storage circuit 210 is respectively connected to the input end of the PFC circuit 100 and the power supply end VCC of the control chip 110. The energy storage circuit 210 is used to generate a startup voltage based on the input voltage of the PFC circuit 100 to start the control chip 110 to make the control chip 110 control the switch tube Q to be turned on or off; the charging and discharging circuit 220 is connected to the energy storage circuit 210. The charging and discharging circuit 220 includes a secondary winding FZ of a coupled inductor. The charging and discharging circuit 220 is used to charge based on the electric energy of the primary winding YZ when the control chip 110 controls the switch tube Q to be turned on, and discharge to supplement the electric energy to the energy storage circuit 210 when the control chip 110 controls the switch tube Q to be turned off, so that the working voltage of the control chip 110 is within a preset voltage range.

[0034] Specifically, the energy storage circuit 210 is mainly used to start the control chip 110. Figure 2 As shown, when the PFC circuit 100 is just started, the input voltage of the PFC circuit 100 can charge the energy storage element inside the energy storage circuit 210 until the voltage of the energy storage element reaches the starting voltage, and then the energy storage circuit 210 generates a starting voltage to start the control chip 110 to work, so that the control chip 110 controls the switch tube Q to turn on or off according to the preset control strategy, and realizes the PFC function of the PFC circuit 100. After starting, the control chip 110 starts to consume electric energy, and the charging rate of the energy storage circuit 210 cannot meet the power consumption speed of the control chip 110, so the voltage of the power supply terminal VCC of the control chip 110 will drop, which will affect the normal operation of the PFC circuit 100.

[0035] Therefore, the power supply circuit 200 of the embodiment of the present invention is further provided with a charging and discharging circuit 220, and the charging and discharging circuit 220 includes a secondary winding FZ of a coupled inductor. When the switch tube Q is turned on, the input voltage of the PFC circuit 100 charges the PFC inductor L, and the voltage across the PFC inductor L rises. Since the PFC inductor L also serves as the primary winding YZ of the coupled inductor, according to the characteristics of the coupled inductor, the secondary winding FZ of the coupled inductor can couple the electric energy on the primary winding YZ to charge, and the voltage across the two ends also rises. When the switch tube Q is turned off, the PFC inductor L is discharged, and the secondary winding FZ is also discharged, so that the energy storage circuit 210 can be supplemented with electric energy, so that the operating voltage of the control chip 110 is within the preset voltage range, so that the control chip 110 can obtain a regulated power supply and work normally. As a result, the power supply circuit 200 realizes the regulated power supply function for the control chip 110, and effectively improves the reliability of the power supply circuit 200.

[0036] In the related art, the control chip 110 usually needs to be provided with a special power supply circuit to provide the control chip 110 with a regulated power supply so that it can work normally. For example, when the PFC circuit works in a circuit with a transformer, the related art usually sets an additional winding on the secondary side of the transformer, and sets a rectifier filter circuit and a DC conversion circuit at the rear end to power the control chip 110. However, the related art needs to add an additional tap to the secondary winding of the transformer, which has high requirements on the design of the transformer, and requires an additional circuit to achieve voltage conversion, so the hardware cost is high. In the embodiment of the present invention, by reusing the PFC inductor L of the PFC circuit 100 as the primary winding YZ of the coupled inductor, the charge and discharge characteristics of the PFC circuit are used to provide a regulated power supply to the control chip 110, so that the structure of the power supply circuit 200 is relatively simple, and will not affect the design of the transformer, thereby effectively reducing the hardware cost of the power supply circuit 200.

[0037] In the above embodiment, an energy storage circuit and a charge-discharge circuit are arranged in the power supply circuit, wherein the energy storage circuit includes a primary winding of a coupled inductor, and the charge-discharge circuit includes a secondary winding of a coupled inductor. The charge-discharge circuit can be charged based on the electric energy of the primary winding when the control chip controls the switch tube to be turned on, and can be discharged to replenish electric energy for the energy storage circuit when the control chip controls the switch tube to be turned off, so that the operating voltage of the control chip is within a preset voltage range, thereby realizing stable power supply to the control chip, and the circuit structure is relatively simple, which effectively reduces the hardware cost of the power supply circuit and improves the reliability of the power supply circuit.

[0038] In some embodiments, reference Figure 3As shown, the energy storage circuit 210 includes: a starting resistor RQ and a first energy storage capacitor C1, wherein one end of the starting resistor RQ is connected to the input end VIN of the PFC circuit 100; one end of the first energy storage capacitor C1 is respectively connected to the other end of the starting resistor RQ and the power supply end VCC of the control chip 110, and the other end of the first energy storage capacitor C1 is grounded GND.

[0039] Specifically, when the PFC circuit 100 is started, the rectifier circuit 300 can input the rectified DC power to the input terminal VIN of the PFC circuit 100. The DC input voltage will charge the first energy storage capacitor C1 through the start-up resistor RQ, so that the voltage at one end of the first energy storage capacitor C1 continues to rise until it reaches the start-up voltage of the control chip 100, so that the control chip 100 can obtain the start-up voltage and start normally. In this way, the energy storage circuit 210 generates a start-up voltage based on the input voltage of the PFC circuit 100 to start the control chip 110.

[0040] In the above process, the starting resistor RQ plays a current limiting role to prevent the first energy storage capacitor C1 from generating a surge current when charging. Figure 3 As shown, the startup resistor RQ may include a first resistor R1, or, Figure 4 As shown, the starting resistor RQ includes a plurality of second resistors R2 connected in series. In both cases, the starting resistor RQ can achieve current limiting, and when a plurality of second resistors R2 are selected as the starting resistor RQ, the difficulty of selecting the starting resistor RQ can also be reduced.

[0041] In some embodiments, reference Figure 5 As shown, the charge and discharge circuit 220 also includes: a first diode D1, a second diode D2, a second energy storage capacitor C3 and a third resistor R3. Among them, the cathode of the first diode D1 is connected to the other end of the start-up resistor RQ and one end of the first energy storage capacitor C1 respectively; the cathode of the second diode D2 is connected to the anode of the first diode D1, and the anode of the second diode D2 is grounded GND; one end of the second energy storage capacitor C2 is connected to the anode of the first diode D1 and the cathode of the second diode D2 respectively; one end of the third resistor R3 is connected to the other end of the second energy storage capacitor C2, and the other end of the third resistor R3 is connected to one end of the secondary winding FZ, and the other end of the secondary winding FZ is grounded GND.

[0042] Furthermore, one end of the primary winding YZ is connected to the input end VIN of the PFC circuit 100, and the other end of the primary winding YZ is connected to the switch tube Q, wherein one end of the primary winding YZ and the other end of the secondary winding FZ are the same-named ends, and the other end of the primary winding YZ and one end of the secondary winding FZ are the same-named ends.

[0043] Furthermore, when the control chip 110 controls the switch tube Q to be turned on, the electric energy of the secondary winding FZ coupled to the primary winding YZ is charged to the second energy storage capacitor C2 through the second diode D2; when the control chip 110 controls the switch tube Q to be turned off, the second energy storage capacitor C2 is discharged through the first diode D1 to supplement the electric energy to the first energy storage capacitor C1, and the electric energy of the secondary winding FZ coupled to the primary winding YZ is supplemented to the first energy storage capacitor C1 through the first diode D1.

[0044] Specifically, since the input terminal VIN of the PFC circuit 100 is usually connected to the rectifier circuit 300, such as Figure 1 As shown. The DC power output by the rectifier circuit 300 is a DC power with an AC component. For example, when the rectifier circuit 300 is Figure 5 When the bridge rectifier circuit is used as shown, the waveform of the DC output by the rectifier circuit 300 can be Figure 6 The steamed bun wave shown in the figure has a large period. For example, when the input of the rectifier circuit 300 is the mains, the period of the direct current is 10ms. Therefore, the input voltage of the PFC circuit 100 will fluctuate periodically according to time, causing the voltage at both ends of the primary winding YZ to fluctuate, thereby causing the secondary winding FB to fluctuate, affecting the effect of supplementing electric energy to the control chip 110, and ultimately affecting the normal power supply of the control chip 110, reducing the reliability of the power supply circuit 200.

[0045] Therefore, reference Figure 5 As shown, the power supply circuit 200 of the embodiment of the present invention is provided with a first diode D1, a second diode D2, a second energy storage capacitor C3 and a third resistor R3 in the charge and discharge circuit 220. When the input voltage is a low voltage, for example, Figure 6 At the moment T1 shown, the input voltage is the first low voltage UD1. In a control cycle of the PFC circuit, when the switch tube Q is turned on, the other end of the primary winding YZ is grounded to GND through the switch tube Q1, and the voltage across the primary winding YZ is equal to the input voltage, that is, the first low voltage UD1. At the same time, one end of the primary winding YZ is a positive voltage, and the other end is grounded to GND through the switch tube Q. Since one end of the primary winding YZ and the other end of the secondary winding FZ are the same end, and the other end of the secondary winding FZ is grounded to GND, one end of the secondary winding FZ is a negative voltage, and the voltage value is the product of the first low voltage UD1 and the turns ratio A of the secondary winding FZ and the primary winding YZ. At this time, refer to Figure 5As shown, one end of the secondary winding FZ is connected to the ground GND through the third resistor R3, the other end of the second energy storage capacitor C2, one end of the second energy storage capacitor C2, the cathode of the second diode D2, and the anode of the second diode D2, so the secondary winding FZ can charge the second energy storage capacitor C2 through the second diode D2. When the charging is completed, the voltage at one end of the second energy storage capacitor C2 is higher than the voltage at the other end, and the voltage difference is also the product of the first low voltage UD1 and the turns ratio A. In this case, the power supply of the control chip 110 is provided by the stored electric energy of the first energy storage capacitor C1. When the switch tube Q is turned off, the other end of the primary winding YZ is connected to the output terminal VOUT. Since the output terminal VOUT is usually a fixed high voltage UG, the voltage at both ends of the primary winding YZ will become a negative voltage, and the voltage value is equal to the difference between the first low voltage UD1 and the fixed high voltage UG. This changes the polarity of the voltage across the secondary winding YZ, and one end of the secondary winding FZ becomes a positive voltage, and the voltage value is the product of the difference between the first low voltage UD1 and the fixed high voltage UG and the turns ratio A. Since the second energy storage capacitor C2 has been charged during the conduction phase of the switch tube Q, the voltage at one end of the second energy storage capacitor C2 is higher than the voltage at the other end. Therefore, the voltage at one end of the first energy storage capacitor C1 is equal to the superposition value of the voltage across the second energy storage capacitor C2 and the voltage across the secondary winding FZ. Figure 5 As shown, in the charge and discharge circuit 220, one end of the second energy storage capacitor C2 can be grounded GND through the anode of the first diode D1, the cathode of the first diode D1, one end of the first energy storage capacitor C1, and the other end of the first energy storage capacitor C1. Therefore, when the voltage at one end of the second energy storage capacitor C2 is higher, the second energy storage capacitor C2 can supplement the first energy storage capacitor C1 with electric energy through the first diode D1. When the switch tube Q is turned off, the second energy storage capacitor C2 can charge the first energy storage capacitor C1 with the superposition value of the voltage at both ends of the second energy storage capacitor C2 and the voltage at both ends of the secondary winding FZ. Therefore, at this time, the second energy storage capacitor C2 and the secondary winding FZ can both discharge through the first diode D1 to supplement the first energy storage capacitor C1 with electric energy.

[0046] In addition, if the voltage division of the third resistor R3 is ignored, the voltage at one end of the second energy storage capacitor C2 can be determined by the following formula (1):

[0047] UC2=UD1*A+(UG-UD1)*A=UG*A (1)

[0048] Among them, UC2 is the voltage at one end of the second energy storage capacitor C2, UD1 is the first low voltage, A is the turns ratio of the secondary winding FZ and the primary winding YZ, and UG is the fixed high voltage of the output terminal VOUT. It can be seen from the above formula (1) that at this time, the output voltage of the second energy storage capacitor C2 will be a fixed value, and has nothing to do with the first low voltage UD1 input at the input terminal VIN. Therefore, the power supply circuit 200 of the embodiment of the present invention can make the operating voltage of the control chip 110 always within the preset voltage range when the input voltage is different voltage values, so that the power supply circuit 200 can provide stable power supply to the control chip 110. For example, Figure 6 At the moment T2 shown, the input voltage is the first medium voltage UZ1. At this time, when the switch tube Q is turned on, the voltage values ​​at both ends of the second energy storage capacitor C2 will increase, and when the switch tube Q is turned off, the voltage values ​​at both ends of the secondary winding FZ will decrease, and after superposition, the voltage at one end of the second energy storage capacitor C2 can still be determined by the above formula (1). The specific principle is similar to the derivation method of the voltage at one end of the second energy storage capacitor C2 at the moment T1 mentioned above, which will not be repeated here.

[0049] Therefore, the power supply circuit can control the operating voltage of the control chip within a preset voltage range, thereby providing a stable power supply voltage to the control chip, thereby improving the reliability of the power supply circuit.

[0050] Furthermore, the second diode D2 is a voltage regulator.

[0051] Specifically, refer to Figure 5 As shown, a voltage regulator can be selected as the second diode D2. At this time, the second diode D2 can also limit the voltage at one end of the second energy storage capacitor C2 to not be higher than the voltage regulation value of the second diode D2, thereby preventing the voltage of the second energy storage capacitor C2 from being too high, ensuring that the operating voltage of the control chip 110 is within the preset voltage range, thereby further improving the reliability of the power supply circuit 200.

[0052] Optionally, refer to Figure 5 As shown, the PFC circuit 100 may further include a third diode D3, the anode of the third diode D3 is connected to the other end of the PFC inductor L, and the cathode of the third diode D3 is connected to the output terminal VOUT. The third diode D3 can effectively prevent the output terminal VOUT voltage from flowing back and has the function of reducing harmonics, thereby optimizing the power factor correction function of the PFC circuit 100.

[0053] In summary, according to the power supply circuit of the PFC circuit control chip of the embodiment of the present invention, an energy storage circuit and a charge-discharge circuit are arranged in the power supply circuit, wherein the energy storage circuit includes a primary winding of a coupled inductor, and the charge-discharge circuit includes a secondary winding of a coupled inductor. The charge-discharge circuit can be charged based on the electric energy of the primary winding when the control chip controls the switch tube to be turned on, and can be discharged to replenish electric energy for the energy storage circuit when the control chip controls the switch tube to be turned off, so that the operating voltage of the control chip is within a preset voltage range, thereby realizing stable power supply to the control chip, and the circuit structure is relatively simple, which effectively reduces the hardware cost of the power supply circuit and improves the reliability of the power supply circuit.

[0054] Corresponding to the above embodiment, the embodiment of the present invention further provides a PFC circuit, referring to Figure 2 As shown, the PFC circuit 100 includes: a PFC inductor L, a switch tube Q and a control chip 110, the PFC inductor L is a primary winding YZ of a coupled inductor; the aforementioned power supply circuit 200, the power supply circuit 200 is respectively connected to the input terminal VIN of the PFC circuit 100 and the power supply terminal VCC of the control chip 110, the power supply circuit 200 includes a secondary winding FZ of a coupled inductor, the power supply circuit 200 is used to generate a start voltage based on the input voltage of the PFC circuit 100 to start the control chip 110 to work, so that the control chip 110 controls the switch tube Q to be turned on or off, and charges based on the electric energy of the primary winding YZ when the switch tube Q is turned on, and discharges when the switch tube Q is turned off, so that the operating voltage of the control chip 110 is within a preset voltage range.

[0055] According to the PFC circuit of the embodiment of the present invention, the aforementioned power supply circuit can realize stable power supply to the control chip in the PFC circuit, and the power supply circuit structure is relatively simple, which effectively reduces the hardware cost of the PFC circuit and improves the reliability of the PFC circuit.

[0056] Corresponding to the above embodiment, the embodiment of the present invention further provides an electronic device, referring to Figure 7a to Figure 7b As shown, the electronic device 1000 includes the aforementioned power supply circuit 200 , or the aforementioned PFC circuit 100 .

[0057] According to the electronic device of the embodiment of the present invention, through the aforementioned power supply circuit or the aforementioned PFC circuit, stable power supply to the PFC circuit control chip in the electronic device can be achieved, and the power supply circuit structure is relatively simple, which effectively reduces the hardware cost of the electronic device and improves the reliability of the electronic device.

[0058] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0059] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0060] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0061] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0062] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A power supply circuit of a PFC circuit control chip, characterized in that: The PFC circuit includes a PFC inductor, a switch tube and the control chip, the PFC inductor is a primary winding of a coupled inductor, and the power supply circuit includes: An energy storage circuit, the energy storage circuit is connected to the input end of the PFC circuit and the power supply end of the control chip respectively, and the energy storage circuit is used to generate a start voltage based on the input voltage of the PFC circuit to start the control chip to enable the control chip to control the switch tube to be turned on or off; A charging and discharging circuit, wherein the charging and discharging circuit is connected to the energy storage circuit, wherein the charging and discharging circuit includes a secondary winding of the coupled inductor, and is used to charge based on the electric energy of the primary winding when the control chip controls the switch tube to be turned on, and to discharge to replenish electric energy to the energy storage circuit when the control chip controls the switch tube to be turned off, so that the operating voltage of the control chip is within a preset voltage range.

2. The power supply circuit according to claim 1, characterized in that: The energy storage circuit comprises: A starting resistor, one end of which is connected to an input end of the PFC circuit; A first energy storage capacitor, one end of which is connected to the other end of the starting resistor and the power supply end of the control chip respectively, and the other end of the first energy storage capacitor is grounded.

3. The power supply circuit according to claim 2, characterized in that: The startup resistor includes a first resistor, or the startup resistor includes a plurality of second resistors connected in series.

4. The power supply circuit according to claim 2, characterized in that: The charging and discharging circuit further comprises: A first diode, wherein a cathode of the first diode is respectively connected to the other end of the starting resistor and one end of the first energy storage capacitor; a second diode, wherein a cathode of the second diode is connected to an anode of the first diode, and the anode of the second diode is grounded; a second energy storage capacitor, one end of which is respectively connected to the anode of the first diode and the cathode of the second diode; a third resistor, one end of the third resistor is connected to the other end of the second energy storage capacitor, the other end of the third resistor is connected to one end of the secondary winding, and the other end of the secondary winding is grounded.

5. The power supply circuit according to claim 4, characterized in that: The second diode is a voltage regulator.

6. The power supply circuit according to claim 4, characterized in that: One end of the primary winding is connected to the input end of the PFC circuit, and the other end of the primary winding is connected to the switch tube, wherein one end of the primary winding and the other end of the secondary winding are the same-named ends, and the other end of the primary winding and one end of the secondary winding are the same-named ends.

7. The power supply circuit according to any one of claims 4 to 6, characterized in that: When the control chip controls the switch tube to be turned on, the secondary winding couples the electric energy of the primary winding to charge the second energy storage capacitor through the second diode; When the control chip controls the switch tube to be disconnected, the second energy storage capacitor discharges through the first diode to replenish electric energy to the first energy storage capacitor, and the secondary winding couples the electric energy of the primary winding to replenish electric energy to the first energy storage capacitor through the first diode.

8. A PFC circuit, characterized in that: include: PFC inductor, switch tube and control chip, the PFC inductor is the primary winding of coupled inductor; According to the power supply circuit according to any one of claims 1 to 7, the power supply circuit is respectively connected to the input end of the PFC circuit and the power supply end of the control chip, the power supply circuit includes a secondary winding of the coupled inductor, and the power supply circuit is used to generate a starting voltage based on the input voltage of the PFC circuit to start the control chip to operate, so that the control chip controls the switch tube to be turned on or off, and charges based on the electric energy of the primary winding when the switch tube is turned on, and discharges when the switch tube is turned off, so that the operating voltage of the control chip is within a preset voltage range.

9. An electronic device, characterized in that: It comprises the power supply circuit according to any one of claims 1 to 7, or the PFC circuit according to claim 8.

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