Synchronous rectification circuit
By designing a resonant module and an anti-compete module in the synchronous rectification circuit, and using the IC600 chip to detect the drain voltage of the MOSFET, the power loss caused by diode rectification and the MOSFET common-circuit problem are solved, achieving a highly efficient rectification function.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HUIZHOU SANHUA IND
- Filing Date
- 2025-04-24
- Publication Date
- 2026-05-29
AI Technical Summary
In traditional switching power supplies, the power loss is relatively large due to the use of diode rectification on the secondary side, and PCB noise may cause the MOSFET to turn on prematurely, resulting in common phenomena.
A synchronous rectification circuit is adopted, utilizing a resonant module and an anti-common-pass module. The drain voltage of the MOSFET is detected by the IC600 chip to ensure that the power MOSFET does not turn on prematurely. This includes a combination design of a resonant module, an anti-common-pass module, a push-pull unit, and a voltage divider unit.
This effectively avoids the common phenomenon of MOSFETs, improves rectification efficiency, and reduces power loss.
Smart Images
Figure CN224305673U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of power electronic conversion technology, and in particular to a synchronous rectifier circuit. Background Technology
[0002] In traditional switching power supplies, diodes are typically used for rectification on the secondary side. However, diodes have a certain forward voltage drop, which leads to significant power loss, especially when the output voltage is low and the current is high. Synchronous rectification technology, on the other hand, uses two power MOSFETs with extremely low on-resistance to replace diodes for rectification. In secondary synchronous rectification, the turn-on and turn-off times of the power MOSFETs are precisely controlled by a control circuit to synchronize them with the voltage phase of the transformer's secondary winding, thereby achieving efficient rectification.
[0003] In related technologies, noise on the PCB board may cause one of the MOSFETs to turn on prematurely, resulting in two power MOSFETs turning on simultaneously. Utility Model Content
[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a synchronous rectification circuit that can prevent MOSFETs from turning on prematurely, thereby avoiding the occurrence of common circuit phenomena.
[0005] The objective of this utility model is achieved through the following technical solution:
[0006] This application provides a synchronous rectification circuit, comprising: a resonant module including a first LLC unit and a second LLC unit, the second LLC unit including a MOSFET Q601, a MOSFET Q603, a push-pull unit, and a chip IC600, the MOSFET Q601 being electrically connected to the first LLC unit, and the chip IC600 being electrically connected to the MOSFET Q601, the MOSFET Q603, and the push-pull unit respectively; and an anti-commutation module including a first voltage divider unit and a second voltage divider unit, the first voltage divider unit being electrically connected to the MOSFET Q601, and the second voltage divider unit being electrically connected to the MOSFET Q602, the first voltage divider unit and the second voltage divider unit being respectively used for electrical connection with power MOSFETs.
[0007] The first LLC unit includes a chip IC100 and an input port, which is electrically connected to the chip IC100.
[0008] The first LLC unit further includes MOSFET Q222, MOSFET Q223, capacitor C229, and transformer T100. MOSFET Q222 is electrically connected to the chip IC100, MOSFET Q223 is electrically connected to MOSFET Q222, capacitor C229 is electrically connected to transformer T100, MOSFETs Q222 and Q223 are electrically connected to transformer T100, and MOSFET Q601 is electrically connected to transformer T100.
[0009] The push-pull unit includes transistors Q604 and Q606 and resistor R163. The first terminal of transistor Q604 is electrically connected to the chip IC600, the second terminal of transistor Q604 is electrically connected to the first terminal of resistor R163, the second terminal of resistor R163 is electrically connected to MOSFET Q603, the first terminal of transistor Q606 is electrically connected to the chip IC600, and the second terminal of transistor Q606 is electrically connected to the first terminal of resistor R163.
[0010] The push-pull unit also includes transistors Q605 and Q607 and resistor R162. The first terminal of transistor Q606 is electrically connected to the chip IC600, the second terminal of transistor Q604 is electrically connected to the first terminal of resistor R162, the second terminal of resistor R162 is electrically connected to MOSFET Q601, the first terminal of transistor Q607 is electrically connected to the chip IC600, and the second terminal of transistor Q607 is electrically connected to the first terminal of resistor R162.
[0011] The anti-common-pass module also includes diode D600, resistors R601, R602, R600, R622, R623, R624, and transistor Q600. The first terminal of diode D600 is electrically connected to the first terminal of resistor R602, and the second terminal of resistor R601 is grounded. The first terminal of resistor R601 is electrically connected to the first terminal of resistor R602, and the second terminal of resistor R601 is electrically connected to the second terminal of resistor R602. The first terminal of resistor R600 is electrically connected to the first terminal of resistor R602, and the second terminal of resistor R600 is electrically connected to the second terminal of resistor R602. Resistor R622... The first terminal of resistor R622 is electrically connected to the first terminal of resistor R600. The second terminal of resistor R623 is electrically connected to the first terminal of resistor R622. The second terminal of resistor R623 is electrically connected to the second terminal of resistor R622. The first terminal of resistor R624 is electrically connected to the first terminal of resistor R623. The second terminal of resistor R624 is electrically connected to the second terminal of resistor R623. The first terminal of transistor Q600 is electrically connected to the first terminal of resistor R624. The second terminal of transistor Q600 is electrically connected to MOSFET Q601. The third terminal of transistor Q600 is grounded.
[0012] The first voltage divider unit includes capacitors C609, C601, and C600. The first terminal of capacitor C609 is electrically connected to the MOSFET Q601, the second terminal of capacitor C609 is electrically connected to the first terminal of capacitor C600, the second terminal of capacitor C600 is electrically connected to the second terminal of resistor R602, the first terminal of capacitor C601 is electrically connected to the first terminal of resistor R602, and the second terminal of capacitor C601 is grounded.
[0013] The anti-common-pass module also includes diode D602, resistors R608, R609, R607, R619, R620, R621, and transistor Q602. The first terminal of diode D602 is electrically connected to the first terminal of resistor R609, and the second terminal of diode D602 is grounded. The first terminal of resistor R608 is electrically connected to the first terminal of resistor R609, and the second terminal of resistor R608 is electrically connected to the second terminal of resistor R609. The first terminal of resistor R607 is electrically connected to the first terminal of resistor R609, and the second terminal of resistor R607 is electrically connected to the second terminal of resistor R609. Resistor R619... The first terminal of resistor R619 is electrically connected to the first terminal of resistor R607. The second terminal of resistor R620 is electrically connected to the first terminal of resistor R619. The second terminal of resistor R620 is electrically connected to the second terminal of resistor R619. The first terminal of resistor R621 is electrically connected to the first terminal of resistor R620. The second terminal of resistor R621 is electrically connected to the second terminal of resistor R620. The first terminal of transistor Q602 is electrically connected to the first terminal of resistor R621. The second terminal of transistor Q602 is electrically connected to MOSFET Q601. The third terminal of transistor Q602 is grounded.
[0014] The second voltage divider unit includes capacitors C610, C607, and C602. The first terminal of capacitor C610 is electrically connected to the MOSFET Q603, the second terminal of capacitor C610 is electrically connected to the first terminal of capacitor C602, the second terminal of capacitor C602 is electrically connected to the second terminal of resistor R609, the first terminal of capacitor C607 is electrically connected to the first terminal of resistor R609, and the second terminal of capacitor C607 is grounded.
[0015] It also includes an input module, which is electrically connected to the input port.
[0016] Compared with the prior art, the present invention has at least the following advantages:
[0017] When the IC600 chip detects that the drain voltage of MOSFET Q601 or MOSFET Q603 is higher than the source voltage, the IC600 chip will turn off the gate drive signal to ensure that one of the power MOSFETs is in the off state, thereby ensuring that the two power MOSFETs do not have a common circuit phenomenon. Attached Figure Description
[0018] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the embodiments will be briefly described below.
[0019] Figure 1 This is a schematic diagram of the synchronous rectification circuit in one embodiment of the present invention;
[0020] Figure 2 This is a circuit diagram of the resonant module and the anti-common-connection module in one embodiment of the present invention;
[0021] Figure 3 This is a circuit diagram of the input module in one embodiment of the present invention. Detailed Implementation
[0022] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.
[0023] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0024] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0025] In traditional switching power supplies, diodes are typically used for rectification on the secondary side. However, diodes have a certain forward voltage drop, which leads to significant power loss, especially when the output voltage is low and the current is high. Synchronous rectification technology uses two power MOSFETs with extremely low on-resistance to replace diodes for rectification. In secondary synchronous rectification, the turn-on and turn-off times of the power MOSFETs are precisely controlled by a control circuit to synchronize them with the voltage phase of the transformer's secondary winding, thereby achieving efficient rectification. However, PCB noise may cause one of the MOSFETs to turn on prematurely, resulting in both power MOSFETs conducting simultaneously.
[0026] To address the aforementioned issues, this application provides a synchronous rectification circuit that can prevent MOSFETs from turning on prematurely, thereby avoiding the occurrence of common circuit phenomena.
[0027] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.
[0028] See Figure 1 and Figure 2 A synchronous rectification circuit includes: a resonant module 100 and an anti-compete module 200. The resonant module 100 includes a first LLC unit and a second LLC unit. The second LLC unit includes MOSFET Q601, MOSFET Q603, a push-pull unit, and a chip IC600. MOSFET Q601 is electrically connected to the first LLC unit, and the chip IC600 is electrically connected to MOSFET Q601, MOSFET Q603, and the push-pull unit, respectively. The anti-compete module 200 includes a first voltage divider unit and a second voltage divider unit. The first voltage divider unit is electrically connected to MOSFET Q601, and the second voltage divider unit is electrically connected to MOSFET Q602. The first voltage divider unit and the second voltage divider unit are respectively used to be electrically connected to power MOSFETs.
[0029] It should be noted that the resonant module 100 is used to detect the output voltage and output current, and the anti-compete module 200 serves as a synchronous rectification module. Furthermore, the first voltage divider unit and the second voltage divider unit are electrically connected to two different power MOSFETs, respectively.
[0030] It should also be noted that when the IC600 chip detects that the drain voltage of MOSFET Q601 or MOSFET Q603 is higher than the source voltage, the IC600 chip will turn off the gate drive signal to ensure that one of the power MOSFETs is in the off state, thereby ensuring that the two power MOSFETs will not be connected simultaneously.
[0031] See Figure 2 In one embodiment, the first LLC unit includes a chip IC100 and an input port, the input port being electrically connected to the chip IC100.
[0032] It should be noted that the input port is +B in the diagram, which is used to connect an external 400V DC power supply.
[0033] See Figure 2 In one embodiment, the first LLC unit further includes MOSFET Q222, MOSFET Q223, capacitor C229, and transformer T100. MOSFET Q222 is electrically connected to chip IC100, MOSFET Q223 is electrically connected to MOSFET Q222, capacitor C229 is electrically connected to transformer T100, MOSFET Q222 and MOSFET Q223 are electrically connected to transformer T100, and MOSFET Q601 is electrically connected to transformer T100.
[0034] It should be noted that MOSFETs Q222 and Q223 are switches, and capacitor C229 is a resonant capacitor.
[0035] See Figure 2 In one embodiment, the push-pull unit includes transistors Q604 and Q606 and resistor R163. The first terminal of transistor Q604 is electrically connected to chip IC600, the second terminal of transistor Q604 is electrically connected to the first terminal of resistor R163, the second terminal of resistor R163 is electrically connected to MOSFET Q603, the first terminal of transistor Q606 is electrically connected to chip IC600, and the second terminal of transistor Q606 is electrically connected to the first terminal of resistor R163.
[0036] It should be noted that resistor R163 is a voltage divider resistor. The push-pull unit provides energy conversion efficiency because the two transistors work alternately. When one transistor is on, the other is off, and the off transistor consumes almost no power. This operating mode reduces unnecessary energy loss in the transistors, allowing energy to be converted into output signal power more efficiently.
[0037] Specifically, the push-pull unit also includes transistors Q605 and Q607 and resistor R162. The first terminal of transistor Q606 is electrically connected to chip IC600, the second terminal of transistor Q604 is electrically connected to the first terminal of resistor R162, the second terminal of resistor R162 is electrically connected to MOSFET Q601, the first terminal of transistor Q607 is electrically connected to chip IC600, and the second terminal of transistor Q607 is electrically connected to the first terminal of resistor R162.
[0038] It should be noted that resistor R162 is a voltage divider resistor. The push-pull unit provides energy conversion efficiency because the two transistors work alternately. When one transistor is on, the other is off, and the off transistor consumes almost no power. This operating mode reduces unnecessary energy loss in the transistors, allowing energy to be converted into output signal power more efficiently.
[0039] See Figure 2 In one embodiment, the anti-common communication module 200 further includes a diode D600, resistors R601, R602, R600, R622, R623, R624, and a transistor Q600. The first terminal of diode D600 is electrically connected to the first terminal of resistor R601, and the second terminal of diode D600 is grounded. The first terminal of resistor R601 is electrically connected to the first terminal of resistor R602, and the second terminal of resistor R601 is electrically connected to the second terminal of resistor R602. The first terminal of resistor R600 is electrically connected to the first terminal of resistor R602, and the second terminal of resistor R600 is electrically connected to the second terminal of resistor R602. The connections are as follows: the first terminal of resistor R622 is electrically connected to the first terminal of resistor R600; the second terminal of resistor R622 is electrically connected to the second terminal of resistor R600; the first terminal of resistor R623 is electrically connected to the first terminal of resistor R622; the second terminal of resistor R623 is electrically connected to the second terminal of resistor R622; the first terminal of resistor R624 is electrically connected to the first terminal of resistor R623; the second terminal of resistor R624 is electrically connected to the second terminal of resistor R623; the first terminal of transistor Q600 is electrically connected to the first terminal of resistor R624; the second terminal of transistor Q600 is electrically connected to MOSFET Q601; and the third terminal of transistor Q600 is grounded.
[0040] It should be noted that diode D600 acts as a clamping pair, and resistors R601, R602, R600, R622, R623, and R624 are current-limiting resistors.
[0041] See Figure 2 In one embodiment, the first voltage divider unit includes capacitors C609, C601, and C600. The first terminal of capacitor C609 is electrically connected to MOSFET Q601, the second terminal of capacitor C609 is electrically connected to the first terminal of capacitor C600, the second terminal of capacitor C600 is electrically connected to the second terminal of resistor R602, the first terminal of capacitor C601 is electrically connected to the first terminal of resistor R602, and the second terminal of capacitor C601 is grounded.
[0042] It should be noted that capacitors C609, C601, and C600 serve as voltage dividers.
[0043] See Figure 2In one embodiment, the anti-common communication module 200 further includes a diode D602, resistors R608, R609, R607, R619, R620, R621, and a transistor Q602. The first terminal of diode D602 is electrically connected to the first terminal of resistor R609, and the second terminal of diode D602 is grounded. The first terminal of resistor R608 is electrically connected to the first terminal of resistor R609, and the second terminal of resistor R608 is electrically connected to the second terminal of resistor R609. The first terminal of resistor R607 is electrically connected to the first terminal of resistor R609, and the second terminal of resistor R607 is electrically connected to the second terminal of resistor R609. The connections are as follows: the first terminal of resistor R619 is electrically connected to the first terminal of resistor R607; the second terminal of resistor R619 is electrically connected to the second terminal of resistor R607; the first terminal of resistor R620 is electrically connected to the first terminal of resistor R619; the second terminal of resistor R620 is electrically connected to the second terminal of resistor R619; the first terminal of resistor R621 is electrically connected to the first terminal of resistor R620; the second terminal of resistor R621 is electrically connected to the second terminal of resistor R620; the first terminal of transistor Q602 is electrically connected to the first terminal of resistor R621; the second terminal of transistor Q602 is electrically connected to MOSFET Q601; and the third terminal of transistor Q602 is grounded.
[0044] It should be noted that diode D602 acts as a clamping pair, and resistors R609, R607, R619, R620, and R621 are current-limiting resistors.
[0045] See Figure 2 In one embodiment, the second voltage divider unit includes capacitors C610, C607, and C602. The first terminal of capacitor C610 is electrically connected to MOSFET Q603, the second terminal of capacitor C610 is electrically connected to the first terminal of capacitor C602, the second terminal of capacitor C602 is electrically connected to the second terminal of resistor R609, the first terminal of capacitor C607 is electrically connected to the first terminal of resistor R609, and the second terminal of capacitor C607 is grounded.
[0046] It should be noted that capacitors C610, C607, and C602 serve as voltage dividers.
[0047] See Figure 3 In one embodiment, it further includes an input module, which is electrically connected to the input port.
[0048] It should be noted that the input module includes, but is not limited to, Figure 3 The circuit diagram shown only requires a 400V DC power supply to be provided to the input port.
[0049] The circuit principle of this application is explained below:
[0050] The drive waveforms output from pins 11 and 16 of chip IC100 are connected to the gates of MOSFETs Q222 and Q223 to control the on / off state of the switching MOSFET pair. The drain of MOSFET Q601 is connected to pin 6 of chip IC600, and the drain of MOSFET Q603 is connected to pin 3 of chip IC600 for detecting the drain voltage of the MOSFETs. Furthermore, the drive waveforms output from pins 1 and 8 of chip IC600 are connected to the gates of MOSFETs Q601 and Q603 through push-pull transistors Q604, Q605, Q606, and Q607.
[0051] Further, in scenario 1: When IC600 detects that the drain voltage of MOSFET Q601 is higher than its source voltage, the internal controller of IC600 determines that no freewheeling operation is needed and forcibly pulls down Pin 8 of IC600, thereby turning off the gate drive signal and ensuring that one of the power MOSFETs is in the off state. It should be explained that when MOSFET Q601 is turned off, there will be a voltage change between the drain and source. Therefore, by setting capacitors C609, C601, and C600 to perform a voltage divider, when the turn-on voltage of transistor Q600 or Q602 is reached, the gate of MOSFET Q601 is connected to ground through transistor Q600. In scenario 1, the power MOSFET electrically connected to the second voltage divider unit is in the on state.
[0052] Scenario 2: When IC600 detects that the drain voltage of MOSFET Q603 is higher than the source voltage, the internal controller of IC600 determines that no freewheeling operation is needed and forcibly pulls down Pin 8 of IC600, thereby turning off the gate drive signal and ensuring that one of the power MOSFETs is in the off state. It should be explained that when MOSFET Q603 turns off, there will be a voltage change between the drain and source. Therefore, by setting capacitors C610, C607, and C602 to perform voltage division, when the turn-on voltage of transistor Q602 is reached, the gate of MOSFET Q603 is connected to ground through transistor Q602. In Scenario 2, the power MOSFET electrically connected to the first voltage divider unit is in the on state.
[0053] The solution of this application has been described in detail above with reference to the accompanying drawings. In the above embodiments, the descriptions of each embodiment have different focuses; for parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments. Those skilled in the art should also understand that the actions and modules involved in the specification are not necessarily essential to this application. Furthermore, it is understood that the steps in the method of this application embodiment can be adjusted, combined, and deleted according to actual needs, and the modules in the device of this application embodiment can be combined, divided, and deleted according to actual needs.
[0054] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.
Claims
1. A synchronous rectifier circuit, characterized in that, include: The resonant module includes a first LLC unit and a second LLC unit. The second LLC unit includes a MOSFET Q601, a MOSFET Q603, a push-pull unit, and a chip IC600. The MOSFET Q601 is electrically connected to the first LLC unit, and the chip IC600 is electrically connected to the MOSFET Q601, the MOSFET Q603, and the push-pull unit, respectively. The anti-compete module includes a first voltage divider unit and a second voltage divider unit. The first voltage divider unit is electrically connected to the MOSFET Q601, and the second voltage divider unit is electrically connected to the MOSFET Q602. The first voltage divider unit and the second voltage divider unit are respectively used to be electrically connected to the power MOSFET.
2. The synchronous rectifier circuit according to claim 1, characterized in that, The first LLC unit includes a chip IC100 and an input port, which is electrically connected to the chip IC100.
3. The synchronous rectifier circuit according to claim 2, characterized in that, The first LLC unit further includes MOSFET Q222, MOSFET Q223, capacitor C229, and transformer T100. MOSFET Q222 is electrically connected to the chip IC100, MOSFET Q223 is electrically connected to MOSFET Q222, capacitor C229 is electrically connected to transformer T100, MOSFETs Q222 and Q223 are electrically connected to transformer T100, and MOSFET Q601 is electrically connected to transformer T100.
4. The synchronous rectifier circuit according to claim 1, characterized in that, The push-pull unit includes transistors Q604 and Q606 and resistor R163. The first terminal of transistor Q604 is electrically connected to the chip IC600, the second terminal of transistor Q604 is electrically connected to the first terminal of resistor R163, the second terminal of resistor R163 is electrically connected to MOSFET Q603, the first terminal of transistor Q606 is electrically connected to the chip IC600, and the second terminal of transistor Q606 is electrically connected to the first terminal of resistor R163.
5. The synchronous rectifier circuit according to claim 1, characterized in that, The push-pull unit also includes transistors Q605 and Q607 and resistor R162. The first terminal of transistor Q606 is electrically connected to the chip IC600, the second terminal of transistor Q604 is electrically connected to the first terminal of resistor R162, the second terminal of resistor R162 is electrically connected to MOSFET Q601, the first terminal of transistor Q607 is electrically connected to the chip IC600, and the second terminal of transistor Q607 is electrically connected to the first terminal of resistor R162.
6. The synchronous rectifier circuit according to claim 5, characterized in that, The anti-common-pass module also includes diode D600, resistors R601, R602, R600, R622, R623, R624, and transistor Q600. The first terminal of diode D600 is electrically connected to the first terminal of resistor R602, and the second terminal of resistor R601 is grounded. The first terminal of resistor R601 is electrically connected to the first terminal of resistor R602, and the second terminal of resistor R601 is electrically connected to the second terminal of resistor R602. The first terminal of resistor R600 is electrically connected to the first terminal of resistor R602, and the second terminal of resistor R600 is electrically connected to the second terminal of resistor R602. Resistor R622... The first terminal of resistor R622 is electrically connected to the first terminal of resistor R600. The second terminal of resistor R623 is electrically connected to the first terminal of resistor R622. The second terminal of resistor R623 is electrically connected to the second terminal of resistor R622. The first terminal of resistor R624 is electrically connected to the first terminal of resistor R623. The second terminal of resistor R624 is electrically connected to the second terminal of resistor R623. The first terminal of transistor Q600 is electrically connected to the first terminal of resistor R624. The second terminal of transistor Q600 is electrically connected to MOSFET Q601. The third terminal of transistor Q600 is grounded.
7. The synchronous rectifier circuit according to claim 6, characterized in that, The first voltage divider unit includes capacitors C609, C601, and C600. The first terminal of capacitor C609 is electrically connected to the MOSFET Q601, the second terminal of capacitor C609 is electrically connected to the first terminal of capacitor C600, the second terminal of capacitor C600 is electrically connected to the second terminal of resistor R602, the first terminal of capacitor C601 is electrically connected to the first terminal of resistor R602, and the second terminal of capacitor C601 is grounded.
8. The synchronous rectifier circuit according to claim 1, characterized in that, The anti-common-pass module also includes diode D602, resistors R608, R609, R607, R619, R620, R621, and transistor Q602. The first terminal of diode D602 is electrically connected to the first terminal of resistor R609, and the second terminal of diode D602 is grounded. The first terminal of resistor R608 is electrically connected to the first terminal of resistor R609, and the second terminal of resistor R608 is electrically connected to the second terminal of resistor R609. The first terminal of resistor R607 is electrically connected to the first terminal of resistor R609, and the second terminal of resistor R607 is electrically connected to the second terminal of resistor R609. Resistor R619... The first terminal of resistor R619 is electrically connected to the first terminal of resistor R607. The second terminal of resistor R620 is electrically connected to the first terminal of resistor R619. The second terminal of resistor R620 is electrically connected to the second terminal of resistor R619. The first terminal of resistor R621 is electrically connected to the first terminal of resistor R620. The second terminal of resistor R621 is electrically connected to the second terminal of resistor R620. The first terminal of transistor Q602 is electrically connected to the first terminal of resistor R621. The second terminal of transistor Q602 is electrically connected to MOSFET Q601. The third terminal of transistor Q602 is grounded.
9. The synchronous rectifier circuit according to claim 8, characterized in that, The second voltage divider unit includes capacitors C610, C607, and C602. The first terminal of capacitor C610 is electrically connected to the MOSFET Q603, the second terminal of capacitor C610 is electrically connected to the first terminal of capacitor C602, the second terminal of capacitor C602 is electrically connected to the second terminal of resistor R609, the first terminal of capacitor C607 is electrically connected to the first terminal of resistor R609, and the second terminal of capacitor C607 is grounded.
10. The synchronous rectifier circuit according to claim 2, characterized in that, It also includes an input module, which is electrically connected to the input port.