Circuit for accelerating turn-off of MOS (Metal Oxide Semiconductor) tube of switching power supply

Abstract

The utility model relates to the technical field of MOS tube turn-off acceleration circuits, in particular to a circuit for accelerating turn-off of an MOS tube of a switching power supply. Comprising an IC chip, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a diode D1, a triode Q1 and an MOS tube Q2, a PWM pin of the IC chip is connected with the resistor R1, the resistor R1 is connected with the diode D1, the resistor R1 is connected with a B pole of the triode Q1, the diode D1 is connected with the resistor R2, and the diode D1 is connected with the resistor R3; according to the utility model, the diode D1, the resistor R2 and the PNP type triode Q1 are additionally arranged on the G pole of the MOS tube to form a reverse absorption and discharge circuit together, a discharge channel is provided for parasitic capacitance of the MOS tube, the turn-off of the MOS tube is effectively accelerated, the circuit uses the simple resistors, diodes and triodes, and the circuit is simple in structure and convenient to use. And the MOS tubes are ingeniously connected in series and in parallel to form a quickly-switched-on discharge channel to accelerate the turn-off of the MOS tubes, so that the normal and stable work of the MOS tubes is ensured.

Description

Technical Field

[0001] This utility model relates to the technical field of MOSFET accelerated turn-off circuits, specifically a circuit for accelerating the turn-off of a MOSFET in a switching power supply. Background Technology

[0002] MOSFETs are essential switching devices in switching power supplies. They control the charging and releasing of transformers, and also provide functions such as current protection, voltage regulation, efficiency improvement, and energy saving. In many applications, stable control of MOSFET turn-on and turn-off is a necessary condition for ensuring the normal operation of MOSFETs. However, a particularly prominent issue is the phenomenon of delayed turn-off caused by parasitic parameters during MOSFET turn-off, which is a major cause of MOSFET damage and high losses. Therefore, developing an effective circuit to accelerate MOSFET turn-off is of significant practical application value.

[0003] Based on this, the present invention provides a circuit for accelerating the turn-off of a MOSFET in a switching power supply, in order to solve the aforementioned technical problems. Summary of the Invention

[0004] The purpose of this invention is to provide a circuit for accelerating the turn-off of a MOSFET in a switching power supply. This circuit provides a discharge path for the parasitic capacitance of the MOSFET, effectively speeding up the turn-off of the MOSFET. The circuit uses simple resistors, diodes, and transistors, and cleverly utilizes their series and parallel connections to form a fast-conducting discharge path to accelerate the turn-off of the MOSFET, ensuring the normal and stable operation of the MOSFET.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A circuit for accelerating the turn-off of a MOSFET in a switching power supply includes an IC chip, resistors R1, R2, R3, and R4, a diode D1, a transistor Q1, and a MOSFET Q2.

[0007] The PWM pin of the IC chip is connected to the resistor R1. The resistor R1 is connected to the diode D1. The resistor R1 is connected to the base (B) of the transistor Q1. The diode D1 is connected to the resistor R2. The diode D1 is connected to the resistor R3. The diode D1 is connected to the gate (G) of the MOSFET Q2. The resistor R2 is connected to the emitter (E) of the transistor Q1. The resistor R3 is connected to the source (S) of the MOSFET Q2. The resistor R3 is connected to the resistor R4. The drain (D) of the MOSFET Q2 is connected to V+ DC power.

[0008] Furthermore, the PWM pin of the IC chip is connected in series with the resistor R1.

[0009] Furthermore, the transistor Q1 is a PNP type transistor.

[0010] Furthermore, the source (S) terminal of the MOS transistor is connected in series with the resistor R4 and then grounded.

[0011] Furthermore, the collector (C) of the transistor Q1 is grounded.

[0012] Furthermore, the transistor Q1 is a PNP type transistor.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] This invention adds a diode D1, a resistor R2, and a PNP transistor Q1 to the gate of a MOSFET to form a reverse absorption discharge circuit. This circuit provides a discharge path for the parasitic capacitance of the MOSFET, effectively accelerating the turn-off of the MOSFET. The circuit uses simple resistors, diodes, and transistors, cleverly utilizing their series and parallel connections to form a fast-conducting discharge path to accelerate the turn-off of the MOSFET, ensuring the normal and stable operation of the MOSFET. Attached Figure Description

[0015] Figure 1 The circuit diagram is for a utility model of a switching power supply circuit that accelerates the turn-off of a MOSFET. Detailed Implementation

[0016] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model. Example

[0017] like Figure 1 As shown, this embodiment provides a circuit for accelerating the turn-off of a MOSFET in a switching power supply, including an IC chip, resistors R1, R2, R3, and R4, diode D1, transistor Q1, and MOSFET Q2. The PWM pin of the IC chip is connected to resistor R1. Resistor R1 is connected to diode D1. Resistor R1 is connected to the base (B) of transistor Q1. Diode D1 is connected to resistor R2. Diode D1 is connected to resistor R3. Diode D1 is connected to the gate (G) of MOSFET Q2. Resistor R2 is connected to the emitter (E) of transistor Q1. Resistor R3 is connected to the source (S) of MOSFET Q2. Resistor R3 is connected to resistor R4. The drain (D) of MOSFET Q2 is connected to V+ DC power.

[0018] In this circuit, the PWM pin of the IC chip is connected in series with resistor R1, transistor Q1 is a PNP transistor, the source of the MOSFET is connected in series with resistor R4 and then grounded, and the collector of transistor Q1 is grounded. Transistor Q1 is a PNP transistor.

[0019] In this embodiment, the switching power supply accelerates the MOSFET turn-off circuit. When the PWM wave output by the IC chip is low, the MOSFET turns off. During the turn-off process, parasitic capacitance discharges between the gate (G) and drain (D) and between the gate (G) and source (S) of the MOSFET, prolonging the turn-off time and potentially damaging the MOSFET. In this circuit, transistor Q1, resistor R2, and diode D1 provide a discharge path for the parasitic capacitance when MOSFET Q2 is turned off, effectively preventing MOSFET damage. This circuit can control the parasitic capacitance discharge time of the MOSFET by adjusting the value of R2, effectively controlling the switching state of the MOSFET. In the circuit, R1 is the current-limiting protection resistor for the PWM wave, resistor R3 is the parasitic inductance discharge resistor, and resistor R4 is the MOSFET output current-limiting resistor.

[0020] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0021] The preferred embodiments of this utility model disclosed above are merely illustrative of the present utility model. These preferred embodiments do not exhaustively describe all details, nor do they limit the utility model to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of this utility model, thereby enabling those skilled in the art to better understand and utilize it. This utility model is limited only by the claims and their full scope and equivalents.

Claims

1. A circuit for accelerating the turn-off of a MOSFET in a switching power supply, characterized in that, IC chip, resistance R1, resistance R2, resistance R3, resistance R4, diode D1, triode Q1 and MOS tube Q2 are included; The PWM pin of the IC chip is connected with the resistance R1, the resistance R1 is connected with the diode D1, the resistance R1 is connected with the B pole of the triode Q1, the diode D1 is connected with the resistance R2, the diode D1 is connected with the resistance R3, the diode D1 is connected with the G pole of the MOS tube Q2, the resistance R2 is connected with the E pole of the triode Q1, the resistance R3 is connected with the S pole of the MOS tube Q2, the resistance R3 is connected with the resistance R4, and the D pole of the MOS tube Q2 is connected with V+ direct current.

2. The circuit for accelerating the turn-off of a MOSFET in a switching power supply according to claim 1, wherein, The PWM pin of the IC chip is connected with the resistance R1 in series.

3. The circuit for accelerating the turn-off of a MOSFET in a switching power supply according to claim 1, wherein, The triode Q1 is a PNP type triode.

4. The circuit for accelerating the turn-off of a MOSFET in a switching power supply according to claim 1, wherein, The S pole of the MOS tube is connected with the resistance R4 in series and then grounded.

5. The circuit for accelerating the turn-off of a MOSFET in a switching power supply according to claim 1, wherein, The C pole of the triode Q1 is grounded.

6. The circuit for accelerating the turn-off of a MOSFET in a switching power supply according to claim 1, wherein, The triode Q1 is a PNP type triode.

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