MOS tube driving circuit applied to floating ground

By designing floating-ground application MOS tube driving circuit, using the switch control unit, voltage stabilization unit and shutdown acceleration unit, the problem of floating potential MOS tube being difficult to directly switch control is solved, and low-cost driving control is achieved.

CN222814469UActive Publication Date: 2025-04-29CHENGDU JIKONG TECH CO LTD
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Patent Information

Application Number
CN202421440706.5
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-06-21
Publication Date
2025-04-29
Estimated Expiration
2034-06-21

AI Technical Summary

Technical Problem

In the prior art, it is difficult to directly control the MOS tube with floating potential with a fixed voltage, resulting in the need to design additional isolation power supply and isolation drive circuit, which increases the circuit cost.

Method used

A floating-applied MOS tube driving circuit is designed, including a switching control unit, a voltage stabilization unit and a shutdown acceleration unit. Through components such as photocouplers and transistors, the switching level signal of the MOS tube is controlled to ensure that the gate and source voltages are within the appropriate range and avoid breakdown.

Benefits of technology

The switch driving control of the floating potential MOS tube is realized, and the circuit structure is simple and the circuit cost is effectively reduced.

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Abstract

The utility model belongs to the technical field of electronic circuits, and particularly discloses a floating application MOS tube driving circuit, which comprises a switch control unit, a voltage stabilizing unit and a turn-off acceleration unit, and is characterized in that the switch control unit is respectively connected with an external power supply and the voltage stabilizing unit and is used for accessing MOS tube switch level signals; the MOS tube is connected with the switch-off acceleration unit and controls on and off of power supply transmission between an external power supply and the voltage stabilization unit according to a switch level signal of the MOS tube, the voltage stabilization unit is connected with the switch-off acceleration unit and used for clamping voltage output to the switch-off acceleration unit within a set voltage range, and the switch-off acceleration unit is connected with a grid electrode and a source electrode of the MOS tube and used for clamping the voltage output to the switch-off acceleration unit within the set voltage range. And the control unit is used for changing the grid voltage of the MOS tube into a high level when the switch control unit is switched on so as to switch on the MOS tube, and pulling down the grid voltage of the MOS tube in an accelerated manner when the switch control unit is switched off so as to switch off the MOS tube. The power MOS tube turn-off circuit is simple in structure, fast in turn-off time, suitable for application scenes where the power MOS tube needs to be turned off fast, and capable of effectively reducing circuit cost at the same time.
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Description

Technical Field

[0001] The utility model belongs to the technical field of electronic circuits, and in particular relates to a floating ground application MOS tube driving circuit. Background Art

[0002] The full name of MOS tube is Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), which is a commonly used electronic component. It is mainly composed of three electrodes: gate, source and drain. The working principle of MOS tube is to control the current flow between source and drain through gate voltage. This control method belongs to voltage-controlled devices. In various circuit applications today, MOS tubes are often used as switches to control signals and loads. In some specific circuit applications, the source of MOS tube is not a fixed potential, but a floating potential. It is impossible to directly use a fixed voltage for switch control. It is often necessary to design an additional isolated power supply to cooperate with the isolated drive circuit for driving, which leads to higher circuit costs. Utility Model Content

[0003] The utility model aims to provide a floating ground application MOS tube driving circuit to solve the above problems existing in the prior art.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] The utility model provides a floating ground application MOS tube driving circuit, comprising a switch control unit, a voltage stabilizing unit and a shutdown acceleration unit. The switch control unit is respectively connected to an external power supply and the voltage stabilizing unit, and is used for accessing a MOS tube switch level signal, and controlling the on and off of power transmission between the external power supply and the voltage stabilizing unit according to the MOS tube switch level signal. The voltage stabilizing unit is connected to the shutdown acceleration unit, and is used for clamping a voltage output to the shutdown acceleration unit within a set voltage range. The shutdown acceleration unit is respectively connected to a gate and a source of the MOS tube, and is used for changing a gate voltage of the MOS tube to a high level when the switch control unit is turned on, so that the MOS tube is turned on; when the switch control unit is turned off, the gate voltage of the MOS tube is accelerated to be pulled down, so that the MOS tube is turned off.

[0006] When it is used, a corresponding MOS tube switch level signal can be applied to the switch control unit. When the MOS tube switch level signal is a high level signal, the switch control unit is turned on, and the voltage output to the shutdown acceleration unit is clamped within a set voltage range through the voltage stabilizing unit to prevent the gate and source of the MOS tube from being broken down by an excessively high voltage. At this time, the shutdown acceleration unit changes the gate voltage of the MOS tube to a high level to turn on the MOS tube. When the MOS tube switch level signal is a low level signal, the switch control unit is turned off. At this time, the shutdown acceleration unit accelerates the gate voltage of the MOS tube to be lowered to quickly turn off the MOS tube.

[0007] In a possible design, the switch control unit includes a photocoupler U1, a power supply end of the photocoupler U1 is connected to an external power supply, an output end of the photocoupler U1 is connected to a voltage stabilizing unit, a control end of the photocoupler U1 is used to access a MOS tube switch level signal, and a ground end of the photocoupler U1 is grounded.

[0008] In a possible design, when the MOS tube switch level signal connected to the control end of the photocoupler U1 is at a high level, the photocoupler U1 is turned on; when the MOS tube switch level signal connected to the control end of the photocoupler U1 is at a low level, the photocoupler U1 is turned off, and the control end of the photocoupler U1 is connected to a protection resistor R3.

[0009] In a possible design, the shutdown acceleration unit includes a diode D2, a resistor R4, a transistor Q1 and a transistor Q2, the positive terminal VD of the diode D2 is connected to the output end of the voltage stabilizing unit, the negative terminal VG is connected to the gate of the MOS tube, one end of the resistor R4 is connected to the positive terminal VD of the diode D2, and the other end is connected to the source of the MOS tube, the base of the transistor Q1 is connected to the positive terminal VD of the diode D2, the emitter is connected to the negative terminal VG of the diode D2, the collector is connected to the base of the transistor Q2, the collector of the transistor Q2 is connected to the positive terminal VD of the diode D2, and the emitter is connected to the source of the MOS tube.

[0010] In a possible design, the transistor Q1 is a PNP transistor, and the transistor Q2 is an NPN transistor.

[0011] In a possible design, a resistor R2 is connected between the cathode terminal VG of the diode D2 and the gate of the MOS tube.

[0012] In one possible design, the voltage stabilizing unit includes a resistor R1 and a diode D3, one end of the resistor R1 is connected to the switch control unit, and the other end is connected to the positive terminal VD of the diode D2, the diode D3 is connected in parallel with the resistor R4, and the cathode of the diode D3 is connected to the positive terminal VD of the diode D2.

[0013] In a possible design, a diode D1 is connected between the resistor R1 and the switch control unit, and the anode of the diode D1 is connected to the switch control unit, and the cathode of the diode D1 is connected to the resistor R1.

[0014] Beneficial effects: The utility model can realize switch drive control of floating potential MOS tube, and the circuit structure is simple, which can effectively reduce circuit cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 It is a circuit diagram of the utility model. DETAILED DESCRIPTION

[0017] It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. The specific structural and functional details disclosed herein are only used to describe the exemplary embodiments of the present invention. However, the present invention can be embodied in many alternative forms, and it should not be understood that the present invention is limited to the embodiments described herein.

[0018] It should be understood that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments can be understood according to specific circumstances.

[0019] In the following description, certain details are provided to facilitate a complete understanding of the example embodiments. However, it will be appreciated by those of ordinary skill in the art that the example embodiments may be implemented without these certain details. For example, the system may be shown in a block diagram to avoid obscuring the example with unnecessary details. In other embodiments, well-known processes, structures, and techniques may not be shown in unnecessary detail to avoid obscuring the embodiments.

[0020] Example:

[0021] This embodiment provides a floating ground application MOS tube driving circuit, such as Figure 1As shown, it includes a switch control unit, a voltage stabilizing unit and a shutdown acceleration unit. The switch control unit is respectively connected to the external power supply and the voltage stabilizing unit, and is used to access the MOS tube switch level signal, and control the on and off of the power transmission between the external power supply and the voltage stabilizing unit according to the MOS tube switch level signal. The voltage stabilizing unit is connected to the shutdown acceleration unit, and is used to clamp the voltage output to the shutdown acceleration unit within a set voltage range. The shutdown acceleration unit is respectively connected to the gate and source of the MOS tube, and is used to change the gate voltage of the MOS tube to a high level when the switch control unit is turned on, so that the MOS tube is turned on, and when the switch control unit is turned off, the gate voltage of the MOS tube is accelerated to be pulled down, so that the MOS tube is turned off.

[0022] Furthermore, the switch control unit includes a photocoupler U1, a power supply end of the photocoupler U1 is connected to an external power supply, an output end of the photocoupler U1 is connected to a voltage stabilizing unit, a control end of the photocoupler U1 is used to access a MOS tube switch level signal, and a ground end of the photocoupler U1 is grounded.

[0023] Furthermore, when the MOS tube switch level signal connected to the control end of the photocoupler U1 is at a high level, the photocoupler U1 is turned on, and when the MOS tube switch level signal connected to the control end of the photocoupler U1 is at a low level, the photocoupler U1 is turned off, and the control end of the photocoupler U1 is connected to a protection resistor R3.

[0024] Further, the shutdown acceleration unit includes a diode D2, a resistor R4, a transistor Q1 and a transistor Q2, the positive terminal VD of the diode D2 is connected to the output end of the voltage stabilizing unit, the negative terminal VG is connected to the gate of the MOS tube, one end of the resistor R4 is connected to the positive terminal VD of the diode D2, and the other end is connected to the source of the MOS tube, the base of the transistor Q1 is connected to the positive terminal VD of the diode D2, the emitter is connected to the negative terminal VG of the diode D2, the collector is connected to the base of the transistor Q2, the collector of the transistor Q2 is connected to the positive terminal VD of the diode D2, and the emitter is connected to the source of the MOS tube.

[0025] Furthermore, the transistor Q1 is a PNP transistor, and the transistor Q2 is an NPN transistor.

[0026] Furthermore, a resistor R2 is connected between the cathode terminal VG of the diode D2 and the gate of the MOS tube.

[0027] Furthermore, the voltage stabilizing unit includes a resistor R1 and a diode D3, one end of the resistor R1 is connected to the switch control unit, and the other end is connected to the positive terminal VD of the diode D2, the diode D3 is connected in parallel with the resistor R4, and the cathode of the diode D3 is connected to the positive terminal VD of the diode D2.

[0028] Furthermore, a diode D1 is connected between the resistor R1 and the switch control unit, and the anode of the diode D1 is connected to the switch control unit, and the cathode of the diode D1 is connected to the resistor R1.

[0029] In specific implementation, the switch control unit composed of the photocoupler U1 can turn on and off the power transmission between the external power supply and the voltage stabilizing unit. When the MOS tube switch level signal MOS-SW connected to the control end of the photocoupler U1 is at a high level, the light-emitting diode of the photocoupler U1 emits light, and the light-emitting diode illuminates the triode of the photocoupler U1, so that the triode of the photocoupler U1 is turned on. When the MOS tube switch level signal MOS-SW connected to the control end of the photocoupler U1 is at a low level, the light-emitting diode of the photocoupler U1 does not emit light, and the triode of the photocoupler U1 is turned off. The voltage stabilizing unit composed of the resistor R1 and the diode D3 can clamp the voltage of the positive terminal VD of the diode D2 within the set voltage range, such as within 15V, to prevent the gate and source of the MOS tube from being broken down by excessive voltage. The diode D2, the resistor R4, the triode Q1 and the triode Q2 constitute a shutdown acceleration unit. When the photocoupler U1 is connected to a high level and turned on, the positive feedback circuit composed of transistors Q1 and Q2 can change the MOS-GATE voltage output by the negative terminal VG of diode D2 to a high level, so that the MOS tube is turned on and works. When the photocoupler U1 is connected to a low level and turned off, the voltage at the positive terminal VD of diode D2 will be discharged through resistor R4, and the voltage at the negative terminal VG of diode D2 connected to the gate of the MOS tube will drop much more slowly. When the voltage drop from the VD terminal to the VG terminal is greater than the transistor dead zone voltage, the transistor Q1 is turned on, and its base current I B The collector current I after amplification by transistor Q2 is amplified by β times. C Then, through the emitter junction of transistor Q1, the positive feedback loop continues to increase, until the negative terminal VG of diode D2 is pulled down to the transistor cut-off voltage, thus achieving the purpose of accelerating the shutdown of the MOS tube. Diode D1 plays a role in circuit unidirectional conduction protection, and protection resistor R3 and resistor R2 can both play a corresponding circuit protection role.

[0030] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A floating ground application MOS tube driving circuit, characterized in that: The invention comprises a switch control unit, a voltage stabilizing unit and a shutdown acceleration unit. The switch control unit is respectively connected to an external power supply and the voltage stabilizing unit, and is used for accessing a MOS tube switch level signal, and controlling the on and off of power transmission between the external power supply and the voltage stabilizing unit according to the MOS tube switch level signal. The voltage stabilizing unit is connected to the shutdown acceleration unit, and is used for clamping the voltage output to the shutdown acceleration unit within a set voltage range. The shutdown acceleration unit is respectively connected to the gate and source of the MOS tube, and is used for changing the gate voltage of the MOS tube to a high level when the switch control unit is turned on, so that the MOS tube is turned on; when the switch control unit is turned off, the gate voltage of the MOS tube is accelerated to be pulled down, so that the MOS tube is turned off.

2. A floating ground application MOS tube driving circuit according to claim 1, characterized in that: The switch control unit includes a photocoupler U1, a power supply end of the photocoupler U1 is connected to an external power supply, an output end of the photocoupler U1 is connected to a voltage stabilizing unit, a control end of the photocoupler U1 is used to access a MOS tube switch level signal, and a ground end of the photocoupler U1 is grounded.

3. A floating ground application MOS tube driving circuit according to claim 2, characterized in that: When the MOS tube switch level signal connected to the control end of the photoelectric coupler U1 is at a high level, the photoelectric coupler U1 is turned on; when the MOS tube switch level signal connected to the control end of the photoelectric coupler U1 is at a low level, the photoelectric coupler U1 is turned off, and the control end of the photoelectric coupler U1 is connected to a protection resistor R3.

4. The floating ground application MOS tube driving circuit according to claim 1, characterized in that: The shutdown acceleration unit includes a diode D2, a resistor R4, a transistor Q1 and a transistor Q2, wherein the positive terminal VD of the diode D2 is connected to the output terminal of the voltage stabilizing unit, and the negative terminal VG is connected to the gate of the MOS tube, one end of the resistor R4 is connected to the positive terminal VD of the diode D2, and the other end is connected to the source of the MOS tube, the base of the transistor Q1 is connected to the positive terminal VD of the diode D2, the emitter is connected to the negative terminal VG of the diode D2, the collector is connected to the base of the transistor Q2, the collector of the transistor Q2 is connected to the positive terminal VD of the diode D2, and the emitter is connected to the source of the MOS tube.

5. The floating ground application MOS tube driving circuit according to claim 4, characterized in that: The transistor Q1 is a PNP transistor, and the transistor Q2 is an NPN transistor.

6. The floating ground application MOS tube driving circuit according to claim 4, characterized in that: A resistor R2 is connected between the cathode terminal VG of the diode D2 and the gate of the MOS tube.

7. The floating ground application MOS tube driving circuit according to claim 4, characterized in that: The voltage stabilizing unit includes a resistor R1 and a diode D3, one end of the resistor R1 is connected to the switch control unit, and the other end is connected to the positive terminal VD of the diode D2, the diode D3 is connected in parallel with the resistor R4, and the cathode of the diode D3 is connected to the positive terminal VD of the diode D2.

8. The floating ground application MOS tube driving circuit according to claim 7, characterized in that: A diode D1 is connected between the resistor R1 and the switch control unit, and the anode of the diode D1 is connected to the switch control unit, and the cathode of the diode D1 is connected to the resistor R1.