Switching tube driving circuit and PFC circuit

Abstract

The invention discloses a switching tube driving circuit and a PFC circuit, and relates to the technical field of electronics, the circuit forms a push-pull structure through a first switching circuit and a second switching circuit which are opposite in control logic, and the control end of the push-pull structure is connected with a preset power supply and a single first switching tube. The push-pull structure is connected with the preset power supply and a second ground wire of the driving side. Wherein the first switch tube is used for connecting the control end of the push-pull structure to a first ground wire on the control side. Based on the circuit structure, the first switch tube is controlled to switch the on-off state through the control signal provided by the control chip, so that the control end forming the push-pull structure is communicated with a high level or a low level, and the push-pull structure enters the opposite on-off state; and thus, the push-pull structure can drive the preset switch tube connected at the rear stage to enter a corresponding on-off state. Signal interference between the driving side and the control side is reduced, and the heat dissipation effect of the driver is improved through the single switch tube.

Description

Technical Field

[0001] This application relates to the field of electronic technology, and in particular to a switching transistor driving circuit and a PFC circuit. Background Technology

[0002] In high-power drive systems, such as power factor correction (PFC) circuits composed of switching transistors of the Insulated Gate Bipolar Transistor (IGBT), the control side is usually driven by low voltage and the drive side is usually driven by high voltage. Therefore, capacitor-isolated drive chips are usually used to drive the power switching transistors in PFC. The isolation capacitors in the drive chip electrically isolate the drive side from the control side to prevent electromagnetic interference between the two from affecting the system operation.

[0003] However, in practice, because the switching transistor needs to switch on and off at high frequency, the rapid charging and discharging of the internal parasitic capacitance will generate displacement current. The displacement current can be transmitted to the control side through the isolation capacitor inside the capacitor isolation chip. This can cause the low-level control signal on the control side to be identified as a high-level control signal, which will cause the switching transistor on the drive side to mistakenly enter the conduction state, resulting in low system control accuracy. Summary of the Invention

[0004] The main objective of this application is to provide a switching transistor drive circuit and a PFC circuit, which aims to solve the technical problem of how to reduce signal crosstalk between the drive side and the control side of the PFC circuit.

[0005] To achieve the above objectives, embodiments of this application provide a switching transistor driving circuit, which includes: a first switching transistor, a first switching circuit, and a second switching circuit; The first terminal of the first switching transistor is connected to the control terminal of the first switching circuit and the control terminal of the second switching circuit, respectively. The control terminal of the first switching transistor is connected to the control chip, and the second terminal of the first switching transistor is connected to the first ground wire. The first terminal of the first switching circuit is connected to the control terminal of the first switching circuit, the second terminal of the first switching circuit is connected to the first terminal of the second switching circuit, the first terminal of the first switching circuit is also used to connect to a preset power supply, and the second terminal of the first switching circuit is also used to connect to a preset switching transistor. The second terminal of the second switching circuit is connected to the second ground wire; The first switching transistor is used to change its on / off state based on the control signal provided by the control chip, so that the on / off states of the first switching circuit and the second switching circuit are different.

[0006] In one embodiment, the first switching circuit includes: a first resistor, a second resistor, and a second switching transistor; The first end of the second switch is connected to the second end of the first resistor, the control end of the second switch is connected to the first end of the second resistor, the second end of the second switch is connected to the first end of the second switch circuit and the control end of the preset switch; the first end of the first resistor is connected to the preset power supply, and the second end of the second resistor is connected to the first end of the first switch.

[0007] In one embodiment, the second switching circuit includes: a third resistor, a fourth resistor, a first capacitor, and a third switching transistor; The first terminal of the third switch is connected to the first terminal of the third resistor, the second terminal of the first switch circuit, and the control terminal of the preset switch. The control terminal of the third switch is connected to the second terminal of the fourth resistor and the first terminal of the first capacitor. The second terminal of the third switch, the second terminal of the third resistor, and the second terminal of the first capacitor are connected to the second ground wire. The first terminal of the fourth resistor is connected to the control terminal of the first switch circuit, the first terminal of the first switch circuit, and the first terminal of the first switch.

[0008] In one embodiment, the second switching circuit further includes: a first Zener diode; The anode of the first Zener diode is connected to the first terminal of the first capacitor and the control terminal of the third switching transistor, and the cathode of the first Zener diode is connected to the second terminal of the fourth resistor.

[0009] In one embodiment, the switching transistor driving circuit further includes: a fifth resistor, a sixth resistor, and a second capacitor; The first terminal of the first switching transistor is connected to the first terminal of the first switching circuit, the control terminal of the first switching circuit, and the control terminal of the second switching circuit, respectively; the control terminal of the first switching transistor is connected to the second terminal of the fifth resistor, the first terminal of the sixth resistor, and the first terminal of the second capacitor, respectively; the drain of the first switching transistor, the second terminal of the sixth resistor, and the second terminal of the second capacitor are connected to the first ground wire; the first terminal of the fifth resistor is connected to the control chip.

[0010] In one embodiment, the switching transistor driving circuit further includes a seventh resistor and a third capacitor; The first end of the seventh resistor is connected to the first end of the first switching circuit and the first end of the third capacitor; the second end of the seventh resistor is connected to the control end of the first switching circuit, the control end of the second switching circuit, and the first end of the first switching transistor; the second end of the third capacitor is connected to the first ground wire.

[0011] In one embodiment, the switching transistor driving circuit further includes: an eighth resistor, a ninth resistor, a tenth resistor, and a fourth capacitor; The first end of the eighth resistor is connected to the second end of the first switching circuit and the first end of the second switching circuit, respectively. The second end of the eighth resistor is connected to the first end of the fourth capacitor and the control end of the preset switching transistor, respectively. The second end of the fourth capacitor is connected to the first end of the ninth resistor, and the second end of the ninth resistor is connected to the second ground wire. The first end of the tenth resistor is connected to the first ground wire, and the second end of the tenth resistor is connected to the second ground wire.

[0012] In one embodiment, the switch driving circuit further includes: an isolation circuit; The input terminal of the isolation circuit is connected to the control chip, and the output terminal of the isolation circuit is connected to the control terminal of the first switching transistor. The isolation circuit is used to perform voltage isolation processing on the control signal output by the control chip, and transmit the voltage-isolated control signal to the first switching transistor.

[0013] In one embodiment, the isolation circuit includes: an eleventh resistor, a twelfth resistor, a fifth capacitor, a sixth capacitor, a seventh capacitor, and a digital isolator; The first power supply pin of the digital isolator is connected to the first power supply and the first terminal of the fifth capacitor, respectively. The input pin of the digital isolator is connected to the second terminal of the eleventh resistor, the first terminal of the twelfth resistor and the first terminal of the sixth capacitor, respectively. The second power supply pin of the digital isolator is connected to the second power supply and the first terminal of the seventh capacitor, respectively. The output pin of the digital isolator is connected to the control terminal of the first switching transistor, and the first terminal of the eleventh resistor is connected to the control chip. The second terminal of the twelfth resistor, the second terminal of the fifth capacitor, and the second terminal of the sixth capacitor are connected to the third ground line, and the second terminal of the seventh capacitor is connected to the first ground line.

[0014] This application embodiment also provides a PFC circuit, the PFC circuit comprising: Two sets of preset switching transistors form one bridge arm; A set of switching transistor drive circuits as described above is used to connect the upper bridge arm of the bridge arm; A set of switching transistor drive circuits as described above is used to connect the lower bridge arm of the bridge arm.

[0015] This application provides a switch driving circuit and a PFC circuit. The switch driving circuit includes: a first switch, a first switching circuit, and a second switching circuit; a first terminal of the first switch is connected to the control terminal of the first switching circuit and the control terminal of the second switching circuit, the control terminal of the first switch is connected to a control chip, and a second terminal of the first switch is connected to a first ground line; a first terminal of the first switching circuit is connected to the control terminal of the first switching circuit, and a second terminal of the first switching circuit is connected to the first terminal of the second switching circuit; the first terminal of the first switching circuit is also used to connect to a preset power supply, and the second terminal of the first switching circuit is also used to connect to a preset switch; a second terminal of the second switching circuit is connected to a second ground line; wherein, the first switch is used to change its on / off state based on the control signal provided by the control chip, so that the on / off states of the first switching circuit and the second switching circuit are different.

[0016] A push-pull structure is formed by two switching circuits with opposite on / off states, consisting of a first switching circuit and a second switching circuit. The control terminals of the push-pull structure are connected to a preset power supply and a single first switching transistor, respectively. The push-pull structure is also connected to a preset power supply providing a high level for the drive side and a second ground line providing a low level for the drive side. The first switching transistor connects the control terminal of the push-pull structure to the first ground line on the control side. Based on this circuit structure, the first switching transistor is controlled by a control signal provided by the control chip to switch its on / off state, causing the control terminal of the push-pull structure to be connected to either a high or low level. This allows the push-pull structure to enter opposite on / off states, thereby driving the subsequent preset switching transistors to enter the corresponding on / off states. This reduces signal interference between the drive and control sides and improves heat dissipation by utilizing a single switching transistor. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of the switching transistor drive circuit of this application in Embodiment 1; Figure 2 This is a schematic diagram of the structure of the switching transistor drive circuit in Embodiment 2 of this application; Figure 3 This is a schematic diagram of the structure of the switching transistor drive circuit in Embodiment 3 of this application.

[0020] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0022] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0023] This application presents a first embodiment of the switch transistor driving circuit; please refer to [link / reference]. Figure 1 The switching transistor driving circuit includes: a first switching transistor 10, a first switching circuit 20, and a second switching circuit 30; The first terminal of the first switching transistor 10 is connected to the control terminal of the first switching circuit 20 and the control terminal of the second switching circuit 30 respectively. The control terminal of the first switching transistor 10 is connected to the control chip 40. The second terminal of the first switching transistor 10 is connected to the first ground line GND1. The first end of the first switching circuit 20 is connected to the control end of the first switching circuit 20, the second end of the first switching circuit 20 is connected to the first end of the second switching circuit 30, the first end of the first switching circuit 20 is also used to connect to the preset power supply 50, and the second end of the first switching circuit 20 is also used to connect to the preset switching tube 60. The second terminal of the second switching circuit 30 is connected to the second ground line GND2; The first switch 10 is used to change its on / off state based on the control signal provided by the control chip 40, so that the on / off states of the first switch circuit 20 and the second switch circuit 30 are different.

[0024] It should be noted that in this embodiment, the control signal can be a PWM signal with a duty cycle of 50%. Correspondingly, the control chip 40 can be a low-power digital signal processor (DSP) capable of outputting PWM signals. It can be driven by the power supplied by the low-voltage power supply to perform various tasks, such as outputting control signals. The preset switch 60 can be an IGBT, which can switch on and off states based on the voltage received from the control terminal to control the high-power transmission at its two ends. The preset power supply 50 refers to a power supply capable of driving the preset switch 60 into a fully conducting state. The output voltage can be adjusted, and the specific voltage selection range of the output voltage of the preset power supply 50 is much larger than the output voltage of the low-voltage power supply that provides power to the control chip 40.

[0025] It should be understood that in this embodiment, the first switching circuit 20 and the second switching circuit 30 have opposite control logic. The control terminals of the first switching circuit 20 and the second switching circuit 30 are connected to form a push-pull structure, which is part of the driving side. The first switching circuit 20 can be connected to a preset power supply 50 to provide a high level, while the second switching circuit 30 can be connected to a second ground line to provide a low level. Since the driving side requires high-power transmission, it needs to be driven by a preset power supply 50 with a relatively high output voltage. Conversely, the control side requires low power consumption and needs a low-voltage power supply with a relatively low output voltage. To avoid electrical interference between the two, the first switching transistor 10 on the control side can be positioned between the control chip 40 and the control terminal of the push-pull structure formed by the first switching circuit 20 and the second switching circuit 30. By connecting the second terminal of the first switching transistor 10 to a first ground line GND1, which is isolated from the second ground line GND2, electrical isolation between the control side and the driving side is achieved. Specifically, the control chip 40 can be regarded as the core of the control side, together with the first switch 10 to form the control side; while the preset switch 60 can be regarded as the core of the drive side, together with the first switch circuit 20 and the second switch circuit 30 to form the drive side.

[0026] It is worth noting that in this embodiment, when a high-level or low-level electrical signal is simultaneously transmitted to the control terminal of the first switch circuit 20 and the control terminal of the second switch circuit 30, the two always maintain a state of one on and one off. That is, when the first switch circuit 20 enters the on state, the second switch circuit 30 simultaneously enters the off state, and when the second switch circuit 30 enters the on state, the first switch circuit 20 simultaneously enters the off state.

[0027] In specific implementation, the control terminals of the first switching circuit 20 and the second switching circuit 30 are both connected to the first terminal of the first switching transistor 10 and the preset power supply 50. In one case, the control signal output by the control chip 40 controls the first switching transistor 10 to enter the off state, and the voltage at the control terminals of the first switching circuit 20 and the second switching circuit 30 can be directly understood as the output voltage provided by the preset power supply 50. In another case, the control signal output by the control chip 40 controls the first switching transistor 10 to enter the on state, and the voltage at the control terminals of the first switching circuit 20 and the second switching circuit 30 can be directly understood as the low level provided by the first ground line GND1. Since the control logic of the on / off states of the first switch circuit 20 and the second switch circuit 30 is opposite, when the first switch circuit 20 is on, the second switch circuit 30 is off, and the control terminal of the preset switch tube 60 is connected to the preset power supply 50 only through the first switch circuit 20 to drive the preset switch tube 60 to conduct; while when the first switch circuit 20 is off and the second switch circuit 30 is on, the control terminal of the preset switch tube 60 is connected to the second ground GND2 only through the second switch circuit 30 to drive the preset switch tube 60 to turn off.

[0028] In this circuit design, the second terminal of the first switch 10 on the control side is connected to the first ground line GND1, while the second switch circuit 30 on the drive side is connected to the second ground line GND2. This circuit structure design effectively reduces high-frequency interference between the control side and the drive side. The displacement current generated by the rapid switching of the preset switch 60's on / off state is not transmitted to the control side through the first switch 10, making the transmission process of the control signal sent by the control chip 40 more stable. Consequently, the process of the circuit driving the preset switch 60 to switch its on / off state is more precise.

[0029] It is worth noting that in this embodiment, the first ground wire GND1 can be understood as a ground wire on the control side, and the second ground wire GND2 can be understood as a ground wire on the drive side, that is, the ground wire in the circuit that controls the power output through the preset switch 60. As a specific case, if the preset switch 60 is working in the PFC circuit, then the second ground wire GND2 can be understood as the negative terminal of the PFC circuit bus.

[0030] This application provides a switching transistor driving circuit. The circuit uses two on / off control logics to maintain opposite first and second switching circuits, forming a push-pull structure. The control terminals of the push-pull structure are connected to a preset power supply and a single first switching transistor. The push-pull structure is also connected to a preset power supply providing a high level for the driving side and a second ground line providing a low level for the driving side. The first switching transistor connects the control terminal of the push-pull structure to a first ground line on the control side. Based on this circuit structure, a control signal provided by a control chip controls the first switching transistor to switch its on / off state, causing the control terminal of the push-pull structure to connect to either a high or low level, thus enabling the push-pull structure to enter opposite on / off states. This allows the push-pull structure to drive the subsequent preset switching transistors into their corresponding on / off states. This reduces signal interference between the driving and control sides and improves heat dissipation by utilizing a single switching transistor.

[0031] Based on the first embodiment of this application, in the second embodiment of this application, the content that is the same as or similar to that in the first embodiment described above can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 2 The first switching circuit 20 includes: a first resistor R1, a second resistor R2, and a second switching transistor; The first end of the second switch is connected to the second end of the first resistor R1, the control end of the second switch is connected to the first end of the second resistor R2, the second end of the second switch is connected to the first end of the second switch circuit 30 and the control end of the preset switch 60; the first end of the first resistor R1 is connected to the preset power supply 50, and the second end of the second resistor R2 is connected to the first end of the first switch 10.

[0032] It should be understood that the second switching transistor Q2 can be any type of driver transistor capable of handling high current, such as a transistor or MOSFET, and can be selected in a package that is easy to disassemble. The physical characteristics of the circuit, such as current control characteristics and heat dissipation characteristics, can be adjusted by changing the specific model of the second switching transistor Q2 to adapt to various operating environments. As a specific example, in this embodiment, such as... Figure 2 As shown, the second switching transistor Q2 can specifically be a P-type transistor.

[0033] It is easy to understand that in this embodiment, the first resistor R1 is a current-limiting resistor set at the first terminal of the second switch Q2, and the second resistor R2 is a current-limiting resistor set at the control terminal of the second switch Q2, which is used to protect the second switch Q2 from being damaged due to excessive current.

[0034] In a specific implementation, the control terminal of the second switch Q2 is connected to the preset power supply 50 and the first terminal of the first switch 10 through the second resistor R2, and the first terminal of the second switch Q2 is also connected to the preset power supply 50 and the first terminal of the first switch 10 through the first resistor R1.

[0035] Based on the above structure, when the control chip 40 controls the first switch 10 to enter the off state, the control terminal voltage of the second switch Q2 is at a high level, the second switch Q2 is in the off state, and the connection circuit between the preset power supply 50 and the control terminal of the preset switch 60 is also turned off, so the preset switch 60 is in the off state. When the control chip 40 controls the first switch 10 to enter the on state, the control terminal voltage of the second switch Q2 is pulled low, the second switch Q2 is in the on state, and the connection circuit between the preset power supply 50 and the control terminal of the preset switch 60 is also turned on, so the preset switch 60 is in the on state.

[0036] Furthermore, in this embodiment, the second switching circuit 30 includes: a third resistor R3, a fourth resistor R4, a first capacitor C1, and a third switching transistor; The first terminal of the third switch is connected to the first terminal of the third resistor R3, the second terminal of the first switch circuit 20, and the control terminal of the preset switch 60. The control terminal of the third switch is connected to the second terminal of the fourth resistor R4 and the first terminal of the first capacitor C1. The second terminal of the third switch, the second terminal of the third resistor R3, and the second terminal of the first capacitor C1 are connected to the second ground GND2. The first terminal of the fourth resistor R4 is connected to the control terminal of the first switch circuit 20, the first terminal of the first switch circuit 20, and the first terminal of the first switch 10.

[0037] It should be understood that the third switch Q3 can be any type of driver transistor, such as a transistor or MOSFET, capable of handling high current, and can be packaged for easy disassembly. The physical characteristics of the circuit, such as current control and heat dissipation, can be adjusted by changing the specific model of the third switch Q3 to adapt to various operating environments. Furthermore, the control logic corresponding to the on / off state of the third switch Q3 should be the opposite of that of the second switch Q2. As a specific example, in this embodiment, such as... Figure 2 As shown, when the second switch Q2 is a P-type transistor, the third switch Q3 can specifically be an N-type MOSFET.

[0038] It should be noted that, in this embodiment, the third resistor R3 serves as a pull-up resistor connecting the control terminal of the preset switch 60 to the second ground GND2, ensuring that the voltage provided by the preset power supply 50 received by the control terminal of the preset switch 60 is more stable when the third switch Q3 enters the off state; the fourth resistor R4 is a current-limiting resistor for the control terminal of the third switch Q3, used to protect the control terminal of the third switch Q3 from damage due to excessive current; and the first capacitor C1 is used to filter the electrical signal received by the control terminal of the third switch Q3.

[0039] In specific implementation, when the control chip 40 controls the first switch 10 to enter the off state, the control terminal of the third switch Q3 is always at a high level because it is directly connected to the preset power supply 50. The third switch Q3 is in the off state, and the connection circuit between the control terminal of the preset switch 60 and the second ground GND2 is also turned on. When the control chip 40 controls the first switch 10 to enter the on state, the voltage of the control terminal of the third switch Q3 is pulled low because it is connected to the first ground GND1. The third switch Q3 is in the off state, and the connection circuit between the control terminal of the preset switch 60 and the second ground GND2 is also turned off.

[0040] Furthermore, in this embodiment, the second switching circuit 30 further includes: a first Zener diode Dw1; The anode of the first Zener diode Dw1 is connected to the first terminal of the first capacitor C1 and the control terminal of the third switch, and the cathode of the first Zener diode Dw1 is connected to the second terminal of the fourth resistor R4.

[0041] It should be noted that in this embodiment, when the first Zener diode Dw1 receives the voltage provided by the preset power supply 50, it is reverse-broken down, that is, reverse-conducted, and a stable voltage drop is generated during reverse conduction, which can divide the voltage at the control terminal of the third switch Q3 to prevent the third switch Q3 from being damaged due to excessive voltage received at the control terminal.

[0042] Furthermore, in this embodiment, the switching transistor driving circuit further includes: a fourth resistor R4, a sixth resistor R6, and a second capacitor C2; The first terminal of the first switching transistor 10 is connected to the first terminal of the first switching circuit 20, the control terminal of the first switching circuit 20, and the control terminal of the second switching circuit 30, respectively; the control terminal of the first switching transistor 10 is connected to the second terminal of the fourth resistor R4, the first terminal of the sixth resistor R6, and the first terminal of the second capacitor C2, respectively; the drain of the first switching transistor 10, the second terminal of the sixth resistor R6, and the second terminal of the second capacitor C2 are connected to the first ground line GND1; the first terminal of the fourth resistor R4 is connected to the control chip 40.

[0043] It should be noted that in this embodiment, the fourth resistor R4 and the sixth resistor R6 together form a voltage divider structure to divide the voltage of the control signal provided by the control chip 40, so as to prevent the voltage from being too high and damaging the control terminal of the first switching transistor 10. At the same time, the fourth resistor R4 also acts as a current-limiting resistor. The second capacitor C2 is used to regulate and filter the control signal received by the control terminal of the first switching transistor 10, so as to improve the control accuracy of the control signal on the switching state of the first switching transistor 10.

[0044] Furthermore, in this embodiment, the switching transistor driving circuit further includes: a seventh resistor R7 and a third capacitor C3; The first end of the seventh resistor R7 is connected to the first end of the first switching circuit 20 and the first end of the third capacitor C3. The second end of the seventh resistor R7 is connected to the control end of the first switching circuit 20, the control end of the second switching circuit 30, and the first end of the first switching transistor 10. The second end of the third capacitor C3 is connected to the first ground wire GND1.

[0045] It should be noted that, in this embodiment, the control terminal of the first switching circuit 20 and the preset power supply 50 can also be connected through an eleventh resistor R11, which is used to limit the current flowing through the first switching transistor 10 when the first switching transistor 10 is turned on, so as to protect the first switching transistor 10 from damage due to overcurrent; the sixth capacitor C6 can be set between the first ground line GND1 and the preset power supply 50, and is used to filter the electrical signal output by the preset power supply 50.

[0046] Furthermore, in this embodiment, the switching transistor driving circuit further includes: an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, and a fourth capacitor C4. The first end of the eighth resistor R8 is connected to the second end of the first switching circuit 20 and the first end of the second switching circuit 30, respectively. The second end of the eighth resistor R8 is connected to the first end of the fourth capacitor C4 and the control terminal of the preset switching transistor 60, respectively. The second end of the fourth capacitor C4 is connected to the first end of the ninth resistor R9, and the second end of the ninth resistor R9 is connected to the second ground line GND2. The first end of the tenth resistor R10 is connected to the first ground line GND1, and the second end of the tenth resistor R10 is connected to the second ground line GND2.

[0047] It should be noted that, in this embodiment, the twelfth resistor R12 can be used as a current-limiting resistor, and is set between the second terminal of the first switching circuit 20, the first terminal of the second switching circuit 30, and the control terminal of the preset switching transistor 60, so as to protect the preset switching transistor 60 from being damaged by excessive current received at its control terminal; the seventh capacitor C7 is used to filter the electrical signal output to the control terminal of the preset switching transistor 60; the ninth resistor R9 is used to limit the current flowing through the seventh capacitor C7, so as to protect the seventh capacitor C7 from being damaged by excessive current received.

[0048] It is easy to understand that, in this embodiment, a tenth resistor R10 with very low impedance can be set between the first ground wire GND1 and the second ground wire GND2 to reduce the influence of harmonic components transmitted in the alternating current on the entire circuit and improve the stability of the circuit.

[0049] Based on the first and / or second embodiments of this application, in the third embodiment of this application, the content that is the same as or similar to that in embodiments one and two above can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 3 The switching transistor drive circuit further includes: an isolation circuit 70; The input terminal of the isolation circuit 70 is connected to the control chip 40, and the output terminal of the isolation circuit 70 is connected to the control terminal of the first switching transistor 10. The isolation circuit 70 is used to perform voltage isolation processing on the control signal output by the control chip 40, and transmit the voltage-isolated control signal to the first switching transistor 10.

[0050] It should be noted that in this embodiment, when the preset switch 60 is used as the switch of the upper arm of the PFC circuit, the first ground line GND1 can be the N line for AC power transmission. However, when the preset switch 60 is used as the switch of the lower arm of the PFC circuit, the first ground line GND1 connected to the drain of the first switch 10 can be the negative terminal of the PFC circuit bus, while the ground line of the control chip 40 is still the N line for AC power transmission. The two cannot be shared. In this case, the control signal provided by the control chip 40 needs to be isolated and level-converted by the isolation circuit 70 before being transmitted to the control terminal of the first switch 10.

[0051] Furthermore, in this embodiment, the isolation circuit 70 includes: an eleventh resistor R11, a twelfth resistor R12, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, and a digital isolator 71. The first power supply pin of the digital isolator 71 is connected to the first power supply and the first terminal of the fifth capacitor C5, respectively. The input pin of the digital isolator 71 is connected to the second terminal of the eleventh resistor R11, the first terminal of the twelfth resistor R12, and the first terminal of the sixth capacitor C6, respectively. The second power supply pin of the digital isolator 71 is connected to the second power supply and the first terminal of the seventh capacitor C7, respectively. The output pin of the digital isolator 71 is connected to the control terminal of the first switching transistor 10, and the first terminal of the eleventh resistor R11 is connected to the control chip 40. The second end of the twelfth resistor R12, the second end of the fifth capacitor C5, and the second end of the sixth capacitor C6 are connected to the third ground line GND3, and the second end of the seventh capacitor C7 is connected to the first ground line GND1.

[0052] It should be noted that the first power supply VCC1 is used to provide power to the control chip 40 and is connected to the first power supply pin of the digital isolator 71; the second power supply VCC2 is used to drive the first switching transistor 10 to switch between on and off states and is connected to the second power supply pin of the digital isolator 71; the sixth capacitor C6 is used to filter the electrical signal received by the first power supply pin of the digital isolator 71; the seventh capacitor C7 is used to filter the electrical signal received by the second power supply pin of the digital isolator 71; the eleventh resistor R11 and the twelfth resistor R12 form a series voltage divider structure to limit the voltage input to the digital isolator 71; the sixth capacitor C6 is used to initially filter the voltage output by the voltage divider structure formed by the eleventh resistor R11 and the twelfth resistor R12.

[0053] In practical implementation, the digital isolator 71 can electrically isolate the input and output terminals, and can perform voltage conversion based on the first voltage provided by the first power supply VCC1 and the second voltage provided by the second power supply VCC2. The power supply (first power supply VCC1) and ground (third ground GND3) of the input terminal can be shared with the control chip 40, and the drive power supply (second power supply VCC2) and ground (first ground GND1) of the output terminal can be shared with the isolation circuit 70. Furthermore, the input and output terminals do not affect each other, further improving the control accuracy of the control chip 40.

[0054] To achieve the above objectives, this application also proposes a PFC circuit, which can also be applied to other specific circuits with bridge arm structures that require power output control. The PFC circuit includes: Two sets of preset switching transistors 60 form a bridge arm; A set of switching transistor drive circuits as described above is used to connect the upper bridge arm of the bridge arm; A set of switching transistor drive circuits as described above is used to connect the lower bridge arm of the bridge arm.

[0055] It should be noted that in this embodiment, the switching transistor drive circuit connected to the control terminal of the preset switching transistor 60 corresponding to the upper bridge arm does not include the isolation circuit 70; while the switching transistor drive circuit connected to the control terminal of the preset switching transistor 60 corresponding to the lower bridge arm includes the isolation circuit 70. This design can reduce the high-frequency interference generated between the control side and the drive side of the upper and lower bridge arms respectively, thereby improving control accuracy.

[0056] It is worth noting that in this embodiment, the first ground line GND1 and the third ground line GND3 are used only to represent the two types of ground lines existing on the control side, and do not specifically refer to any particular ground line. Therefore, the first ground line GND1 in the upper arm's switching transistor drive circuit proposed in this embodiment is not the same as the first ground line GND1 in the lower arm's switching transistor drive circuit, but should be understood as the third ground line GND3 in the lower arm's switching transistor drive circuit.

[0057] Compared with the prior art, the other beneficial effects of the PFC circuit provided in this application embodiment are the same as the beneficial effects of the switch driving circuit provided in the above embodiments, and the other technical features of the PFC circuit are the same as the features disclosed in the various embodiments of the above switch driving circuit, which will not be repeated here.

[0058] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent scope of this application.

Claims

1. A switching transistor driving circuit, characterized in that, The switching transistor driving circuit includes: a first switching transistor, a first switching circuit, and a second switching circuit; The first terminal of the first switching transistor is connected to the control terminal of the first switching circuit and the control terminal of the second switching circuit, respectively. The control terminal of the first switching transistor is connected to the control chip, and the second terminal of the first switching transistor is connected to the first ground wire. The first terminal of the first switching circuit is connected to the control terminal of the first switching circuit, the second terminal of the first switching circuit is connected to the first terminal of the second switching circuit, the first terminal of the first switching circuit is also used to connect to a preset power supply, and the second terminal of the first switching circuit is also used to connect to a preset switching transistor. The second terminal of the second switching circuit is connected to the second ground wire; The first switching transistor is used to change its on / off state based on the control signal provided by the control chip, so that the on / off states of the first switching circuit and the second switching circuit are different.

2. The switching transistor driving circuit as described in claim 1, characterized in that, The first switching circuit includes: a first resistor, a second resistor, and a second switching transistor; The first end of the second switch is connected to the second end of the first resistor, the control end of the second switch is connected to the first end of the second resistor, the second end of the second switch is connected to the first end of the second switch circuit and the control end of the preset switch; the first end of the first resistor is connected to the preset power supply, and the second end of the second resistor is connected to the first end of the first switch.

3. The switching transistor driving circuit as described in claim 1, characterized in that, The second switching circuit includes: a third resistor, a fourth resistor, a first capacitor, and a third switching transistor; The first terminal of the third switch is connected to the first terminal of the third resistor, the second terminal of the first switch circuit, and the control terminal of the preset switch. The control terminal of the third switch is connected to the second terminal of the fourth resistor and the first terminal of the first capacitor. The second terminal of the third switch, the second terminal of the third resistor, and the second terminal of the first capacitor are connected to the second ground wire. The first terminal of the fourth resistor is connected to the control terminal of the first switch circuit, the first terminal of the first switch circuit, and the first terminal of the first switch.

4. The switching transistor driving circuit as described in claim 3, characterized in that, The second switching circuit also includes: a first Zener diode; The anode of the first Zener diode is connected to the first terminal of the first capacitor and the control terminal of the third switching transistor, and the cathode of the first Zener diode is connected to the second terminal of the fourth resistor.

5. The switching transistor driving circuit as described in claim 1, characterized in that, The switching transistor driving circuit also includes: a fifth resistor, a sixth resistor, and a second capacitor; The first terminal of the first switching transistor is connected to the first terminal of the first switching circuit, the control terminal of the first switching circuit, and the control terminal of the second switching circuit, respectively; the control terminal of the first switching transistor is connected to the second terminal of the fifth resistor, the first terminal of the sixth resistor, and the first terminal of the second capacitor, respectively; the drain of the first switching transistor, the second terminal of the sixth resistor, and the second terminal of the second capacitor are connected to the first ground wire; the first terminal of the fifth resistor is connected to the control chip.

6. The switching transistor driving circuit as described in claim 1, characterized in that, The switching transistor drive circuit also includes: a seventh resistor and a third capacitor; The first end of the seventh resistor is connected to the first end of the first switching circuit and the first end of the third capacitor; the second end of the seventh resistor is connected to the control end of the first switching circuit, the control end of the second switching circuit, and the first end of the first switching transistor; the second end of the third capacitor is connected to the first ground wire.

7. The switching transistor driving circuit as described in claim 1, characterized in that, The switching transistor drive circuit also includes: an eighth resistor, a ninth resistor, a tenth resistor, and a fourth capacitor; The first end of the eighth resistor is connected to the second end of the first switching circuit and the first end of the second switching circuit, respectively. The second end of the eighth resistor is connected to the first end of the fourth capacitor and the control end of the preset switching transistor, respectively. The second end of the fourth capacitor is connected to the first end of the ninth resistor, and the second end of the ninth resistor is connected to the second ground wire. The first end of the tenth resistor is connected to the first ground wire, and the second end of the tenth resistor is connected to the second ground wire.

8. The switching transistor drive circuit as described in any one of claims 1-7, characterized in that, The switching transistor driving circuit also includes: an isolation circuit; The input terminal of the isolation circuit is connected to the control chip, and the output terminal of the isolation circuit is connected to the control terminal of the first switching transistor. The isolation circuit is used to perform voltage isolation processing on the control signal output by the control chip, and transmit the voltage-isolated control signal to the first switching transistor.

9. The switching transistor driving circuit as described in claim 8, characterized in that, The isolation circuit includes: an eleventh resistor, a twelfth resistor, a fifth capacitor, a sixth capacitor, a seventh capacitor, and a digital isolator; The first power supply pin of the digital isolator is connected to the first power supply and the first terminal of the fifth capacitor, respectively. The input pin of the digital isolator is connected to the second terminal of the eleventh resistor, the first terminal of the twelfth resistor and the first terminal of the sixth capacitor, respectively. The second power supply pin of the digital isolator is connected to the second power supply and the first terminal of the seventh capacitor, respectively. The output pin of the digital isolator is connected to the control terminal of the first switching transistor, and the first terminal of the eleventh resistor is connected to the control chip. The second terminal of the twelfth resistor, the second terminal of the fifth capacitor, and the second terminal of the sixth capacitor are connected to the third ground line, and the second terminal of the seventh capacitor is connected to the first ground line.

10. A PFC circuit, characterized in that, The PFC circuit includes: Two sets of preset switching transistors form one bridge arm; A set of switching transistor drive circuits as described in any one of claims 1-7, for connecting the upper bridge arm of the bridge arm; A set of switching transistor drive circuits as described in any one of claims 8-9, for connecting the lower bridge arm of the bridge arm.

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