Quick turn-off control circuit for MOS (Metal Oxide Semiconductor) tube
By introducing a residual voltage discharge circuit into the MOSFET control circuit, and utilizing a combination of transistors and diodes, the residual voltage between the gate and source of the MOSFET can be rapidly discharged, solving the problem of the MOSFET's inability to turn off quickly and improving the reliability and stability of the control.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-08
- Publication Date
- 2026-03-06
AI Technical Summary
In switching control circuits, the residual voltage stored in the gate-source equivalent capacitance of a MOSFET prevents it from being turned off quickly, affecting its control reliability and stability.
A MOSFET control circuit and a residual voltage discharge circuit are used. The residual voltage discharge circuit composed of a transistor and a diode enables the rapid discharge of the residual voltage between the gate and source of the MOSFET to ground. The saturation conduction of transistor Q1 and the reverse cutoff of diode D1 control the current path to ensure the rapid turn-off of the MOSFET.
It improves the reliability and stability of MOSFET turn-off control, has a simple structure and low cost, and achieves fast turn-off of MOSFET.
Smart Images
Figure CN223978635U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of MOSFET fast turn-off control technology, specifically relating to a MOSFET fast turn-off control circuit. Background Technology
[0002] In electronic technology, reliable turn-off control of MOSFETs is a key technology for their application. When MOSFETs are used in switching control circuits, the residual voltage stored in the equivalent capacitance between the gate and source prevents them from achieving fast turn-off control, thus reducing the switching control speed of MOSFETs.
[0003] Most existing solutions directly drive MOSFETs through the ordinary pins of the MCU microprocessor. However, the pin current carrying capacity of the MCU microprocessor is limited, which cannot meet the function of rapid discharge of residual voltage, thus affecting the reliability and stability of MOSFET turn-off control and having a certain impact on the application of the product.
[0004] To address this, a fast turn-off control circuit for MOSFETs is proposed. Utility Model Content
[0005] The purpose of this invention is to provide a fast turn-off control circuit for a MOSFET to solve the problems mentioned in the background section. The fast turn-off control circuit for a MOSFET provided by this invention features simple structure, high reliability, and low cost.
[0006] To achieve the above objectives, this utility model provides the following technical solution: a MOSFET fast turn-off control circuit, comprising a MOSFET control circuit and a residual voltage discharge circuit, wherein the MOSFET control circuit includes a MOSFET Q2, the source of MOSFET Q2 is connected to ground, the drain of MOSFET Q2 is connected to one end of load R4, and the other end of load R4 is connected to VCC; the residual voltage discharge circuit includes a transistor Q1, the collector of transistor Q1 is connected to ground, the emitter of transistor Q1 is connected to pin 2 of resistor R2, pin 1 of resistor R2 is connected to the gate of MOSFET Q2 and the base of transistor Q1 respectively, the resistance of resistor R2 is 10Ω, and the base of transistor Q1 is also connected to a PIN terminal.
[0007] To act as a reverse blocking diode and prevent residual voltage discharge current from flowing to the PIN terminal, a diode D1 is further connected between the base of transistor Q1 and the gate of MOSFET Q2. The positive terminal of diode D1 is connected to the base of transistor Q1, and the negative terminal of diode D1 is connected to the gate of MOSFET Q2.
[0008] To serve as a current-limiting resistor for the control signal, a resistor R1 with a resistance of 100Ω is further connected between the base of transistor Q1 and the PIN terminal.
[0009] Furthermore, the PIN terminal is the switching control signal input terminal for MOSFET Q2.
[0010] To serve as a bias resistor between the gate and source of MOSFET Q2, a resistor R3 with a resistance of 10KΩ is further connected between the gate and source of MOSFET Q2.
[0011] Compared with the prior art, the beneficial effects of this utility model are:
[0012] This invention utilizes a residual voltage discharge circuit at the gate control input terminal of a MOSFET to rapidly discharge the residual voltage between the gate and source of the MOSFET to ground, ensuring that the MOSFET can be quickly turned off during turn-off control, thereby improving the reliability of MOSFET turn-off control. It features simple structure, high reliability, and low cost. Attached Figure Description
[0013] Figure 1 This is the circuit diagram of this utility model. Detailed Implementation
[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0015] Example 1
[0016] Please see Figure 1 This utility model provides the following technical solution: a MOSFET fast turn-off control circuit, including a MOSFET control circuit and a residual voltage discharge circuit. The MOSFET control circuit includes a MOSFET Q2, which is an N-channel MOSFET. The source of MOSFET Q2 is connected to ground, and the drain of MOSFET Q2 is connected to one end of a load R4. The other end of the load R4 is connected to VCC. The residual voltage discharge circuit includes a transistor Q1, which is a PNP type, model S8550, serving as a residual voltage discharge switch. The collector of transistor Q1 is connected to ground, and the emitter of transistor Q1 is connected to pin 2 of resistor R2. Pin 1 of resistor R2 is connected to both the gate of MOSFET Q2 and the base of transistor Q1. The resistance of resistor R2 is 10Ω, serving as a residual voltage discharge resistor. The base of transistor Q1 is also connected to a PIN terminal, which is the input terminal for the switch control signal of MOSFET Q2.
[0017] Specifically, a diode D1 is connected between the base of transistor Q1 and the gate of MOSFET Q2. The diode D1 is an SS14 type diode, which acts as a reverse blocking diode to prevent residual voltage discharge current from flowing to the PIN terminal. The positive terminal of diode D1 is connected to the base of transistor Q1, and the negative terminal of diode D1 is connected to the gate of MOSFET Q2.
[0018] By adopting the above technical solution, when the control signal input at the PIN terminal is high, diode D1 is forward-biased and transistor Q1 is reverse-biased and cut off. The voltage between the gate and source of MOSFET Q2 is high, MOSFET Q2 is turned on, and load R4 is turned on. When the control signal input at the PIN terminal is low, the residual voltage between the gate and source of MOSFET Q2 causes diode D1 to be reverse-biased and cut off. The residual voltage current flows through resistor R2, the Veb of transistor Q1, and resistor R1, causing transistor Q1 to saturate and turn on. The residual voltage between the gate and source of MOSFET Q2 is discharged to ground through resistor R2 and transistor Q1, realizing rapid discharge of the residual voltage between the gate and source of MOSFET Q2, accelerating the turn-off of MOSFET Q2, and improving the reliability and stability of MOSFET turn-off control.
[0019] This invention utilizes a residual voltage discharge circuit at the gate control input terminal of a MOSFET to rapidly discharge the residual voltage between the gate and source of the MOSFET to ground, ensuring that the MOSFET can be quickly turned off during turn-off control, thereby improving the reliability of MOSFET turn-off control. It features simple structure, high reliability, and low cost.
[0020] Specifically, a resistor R1 with a resistance of 100Ω is connected between the base of transistor Q1 and its pin terminal.
[0021] The above technical solution is used as a current-limiting resistor for the control terminal signal.
[0022] Example 2
[0023] The difference between this embodiment and embodiment 1 is that, specifically, a resistor R3 is connected between the gate and the source of MOS transistor Q2, and the resistance of resistor R3 is 10KΩ.
[0024] The above technical solution is used as the bias resistor between the gate and source of MOS transistor Q2.
[0025] In summary, this invention achieves rapid grounding of the residual voltage between the gate and source of the MOSFET through a residual voltage discharge circuit at the gate control input terminal of the MOSFET, ensuring that the MOSFET can be quickly turned off during turn-off control, thereby improving the reliability of the MOSFET turn-off control. It features simple structure, high reliability, and low cost.
[0026] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A fast turn-off control circuit for a MOSFET, characterized in that: The application relates to a MOS transistor control circuit and a residual voltage discharge circuit, wherein the MOS transistor control circuit comprises a MOS transistor Q2, the source of the MOS transistor Q2 is connected with a ground terminal, the drain of the MOS transistor Q2 is connected with one end of a load R4, the other end of the load R4 is connected with a VCC terminal, the residual voltage discharge circuit comprises a triode Q1, the collector of the triode Q1 is connected with the ground terminal, the emitter of the triode Q1 is connected with the 2-pin of a resistor R2, the 1-pin of the resistor R2 is connected with the gate of the MOS transistor Q2 and the base of the triode Q1 respectively, and the base of the triode Q1 is further connected with a PIN terminal.
2. The MOSFET fast turn-off control circuit of claim 1, wherein: A diode D1 is connected between the base of the triode Q1 and the gate of the MOS transistor Q2, the positive terminal of the diode D1 is connected with the base of the triode Q1, and the negative terminal of the diode D1 is connected with the gate of the MOS transistor Q2.
3. The MOSFET fast turn-off control circuit of claim 1, wherein: A resistor R1 is connected between the base of the triode Q1 and the PIN terminal.
4. The MOSFET fast turn-off control circuit of claim 1, wherein: The PIN terminal is a switch control signal input terminal of the MOS transistor Q2.
5. The MOSFET fast turn-off control circuit of claim 1, wherein: A resistor R3 is connected between the gate of the MOS transistor Q2 and the source of the MOS transistor Q2.
6. The MOSFET fast turn-off control circuit of claim 1, wherein: The resistance of the resistor R2 is 10 ohms.
7. The MOSFET fast turn-off control circuit of claim 3, wherein: The resistance of the resistor R1 is 100 ohms.
8. The MOSFET fast turn-off control circuit of claim 5, wherein: The resistance of the resistor R3 is 10K ohms.