WO2021097898A1

WO2021097898A1 - High-current switch circuit having reverse connection prevention function

Info

Publication number: WO2021097898A1
Application number: PCT/CN2019/121840
Authority: WO
Inventors: 刘翠萍
Original assignee: 刘翠萍
Priority date: 2019-11-20
Filing date: 2019-11-29
Publication date: 2021-05-27
Also published as: CN210957794U

Abstract

A high-current switch circuit having a reverse connection prevention function, comprising a reverse connection prevention unit (10), a switch unit (20), and a control unit (30). Signal output ends of the reverse connection prevention unit (10) and the control unit (30) are connected to a signal input end of the switch unit (20). The reverse connection prevention unit (10) comprises an N-channel MOS transistor Q1, a resistor R1 and a resistor R2. One end of the resistor R1 is connected to a positive pole of a power supply, and the other end is connected to one end of the resistor R2. The other end of the resistor R2 is connected to an S pole of the N-channel MOS transistor Q1. A G pole of the N-channel MOS transistor Q1 is connected to a common connection point of the resistors R1 and R2, and a D pole of the N-channel MOS transistor Q1 is connected to a negative pole of the power supply. Due to the coordination of the N-channel MOS transistor Q1, the resistor R1 and the resistor R2, when the power supply is reversely connected, the G pole of the N-channel MOS transistor Q1 is of a negative voltage, and in this case, the N-channel MOS transistor Q1 is cut off to achieve the purpose of reverse connection prevention. In addition, the working state of the switch unit (20) is controlled by the control unit (30), thereby ensuring the normal work of the circuit, and avoiding the damage to a load.

Description

A high-current switch circuit capable of preventing reverse connection

Technical field

The utility model relates to the technical field of anti-reverse connection circuits, in particular to an anti-reverse high current switch circuit.

Background technique

In the actual application of electronic products, when the positive and negative poles of the power supply are connected reversely, an extremely large current will be generated, which will burn all the components of the subsequent load, so a reverse connection protection circuit is required.

At present, under normal circumstances, the DC power input anti-reverse connection protection circuit uses the unidirectional conductivity of the diode to realize the anti-reverse connection protection. This kind of connection is simple and reliable, but when the input current is large, the diode voltage drop will be too large, the heat will be large, and the power consumption will have a very large impact.

Utility model content

Based on this, it is necessary to provide a high-current switching circuit that prevents reverse connection.

An anti-reverse high-current switch circuit includes an anti-reverse unit, a switch unit, and a control unit. The signal output ends of the anti-reverse unit and the control unit are connected to the signal input end of the switch unit;

The anti-connection unit includes an N-channel MOS transistor Q1, resistors R1 and R2. One end of the resistor R1 is connected to the positive electrode of the power supply, the other end is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the S of the N-channel MOS transistor Q1. The poles are connected, the G pole of the N-channel MOS transistor Q1 is connected to the common connection point of the resistors R1 and R2, and the D pole of the N-channel MOS transistor Q1 is connected to the negative electrode of the power supply.

In one of the embodiments, the switch unit includes an N-channel MOS transistor Q2 and a resistor R6, and two ends of the resistor R6 are respectively connected to the G pole and the S pole of the N-channel MOS transistor Q2.

In one of the embodiments, the switch unit further includes an overvoltage protection Z1, and the overvoltage protection Z1 is connected in parallel with the resistor R6.

In one of the embodiments, the control unit includes a switch SW1, a resistor R4, and a resistor R5. One end of the switch SW1 is connected to the positive electrode of the power supply, the other end is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to one end of the resistor R5. , The other end of the resistor R5 is connected to the negative output end of the power supply, and the G pole of the N-channel MOS transistor Q2 is connected to the common connection point between the resistor R4 and the resistor R5.

In one of the embodiments, the anti-reverse high-current switch circuit further includes an indicating unit, the indicating unit includes LED1 and resistor R3, LED1 and resistor R3 are connected in series, the negative electrode of LED1 is connected to the ground, and the resistance of resistor R3 One end is connected to the common connection point between the switch SW1 and the resistor R4.

In one of the embodiments, the model of the N-channel MOS transistor Q1 is IRFB7430.

The above-mentioned anti-reversal high-current switching circuit is set through the cooperation of N-channel MOS transistor Q1, resistors R1 and R2. When the power supply is connected reversely, G on the N-channel MOS transistor Q1 is extremely negative. The N-channel MOS transistor Q1 is cut off to achieve the purpose of anti-reverse connection. The circuit structure is simple and the design is reasonable. The N-channel MOS transistor Q1 with low internal resistance is adopted, which greatly reduces the internal resistance of the switch and has low power loss. At the same time, the switch unit 20 The control unit 30 controls the working state to ensure the normal operation of the circuit and avoid damage to the load.

Description of the drawings

Figure 1 is a circuit diagram of an anti-reverse high-current switch circuit according to an embodiment of the utility model.

Detailed ways

In order to make the above objectives, features and advantages of the present utility model more obvious and easy to understand, the specific implementation of the present utility model will be described in detail below with reference to the drawings. In the following description, many specific details are explained in order to fully understand the present invention. However, the present utility model can be implemented in many other ways different from those described here, and those skilled in the art can make similar improvements without departing from the connotation of the present utility model. Therefore, the present utility model is not subject to the specific embodiments disclosed below. limit.

It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or a central element may also be present. When an element is considered to be "connected" to another element, it can be directly connected to the other element or an intermediate element may be present at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only, and are not meant to be the only embodiments.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of the present utility model. The terminology used in the description of the present utility model herein is only for the purpose of describing specific embodiments, and is not intended to limit the present utility model. The term "and/or" as used herein includes any and all combinations of one or more related listed items.

As shown in Figure 1, a high-current switch circuit with anti-reverse connection includes an anti-reverse unit 10, a switch unit 20, and a control unit 30. The signal output terminals of the anti-reverse unit 10 and the control unit 30 are connected to the switch unit 20. Signal input terminal connection;

The anti-connection unit 10 includes an N-channel MOS transistor Q1, resistors R1 and R2. One end of the resistor R1 is connected to the positive electrode of the power supply, the other end is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the N-channel MOS transistor Q1. The S pole is connected, the G pole of the N-channel MOS transistor Q1 is connected to the common connection point of the resistors R1 and R2, and the D pole of the N-channel MOS transistor Q1 is connected to the negative electrode of the power supply.

The G pole of the N-channel MOS transistor Q1 of the anti-reverse unit 10 is controlled by the divided voltage signal of R1 and R2. When the G pole on R2 is at a positive voltage, the N-channel MOS transistor Q1 is turned on. When the G pole on R2 is not When the voltage is negative or negative, the N-channel MOS transistor Q1 is turned off. When the power supply is reversed, the G on R2 is extremely negative voltage. At this time, the N-channel MOS transistor Q1 is turned off to achieve the purpose of anti-reverse connection. The control unit 30 controls the switch unit 20 to turn on to realize the circuit conduction.

In this way, an anti-reverse high-current switching circuit is provided through the cooperation of the N-channel MOS transistor Q1, resistors R1 and R2. When the power supply is connected reversely, the G on the N-channel MOS transistor Q1 is extremely negative. When the N-channel MOS transistor Q1 is turned off, the purpose of anti-reverse connection is realized. The circuit structure is simple and the design is reasonable. The N-channel MOS transistor Q1 with low internal resistance is adopted, which greatly reduces the internal resistance of the switch and the power loss is small. At the same time, the switch unit 20 The working state is controlled by the control unit 30, which ensures the normal operation of the circuit and avoids damage to the load.

Further, in order to prevent the N-channel MOS transistor Q2 from being falsely triggered, the switch unit 20 includes an N-channel MOS transistor Q2 and a resistor R6. The two ends of the resistor R6 are respectively connected to the G and S electrodes of the N-channel MOS transistor Q2. connection.

In this way, when the G pole of the N-channel MOS transistor Q2 has no signal, the resistor R6 and the S pole have the same potential to prevent false triggering.

Further, in order to prevent the overvoltage of the G pole signal of the N-channel MOS transistor Q2 from being broken down, the switch unit 20 further includes an overvoltage protection Z1, and the overvoltage protection Z1 is connected in parallel with the resistor R6.

In this way, when the G pole signal of the N-channel MOS transistor Q2 is too large, the overvoltage protection Z1 is reversely broken down, effectively preventing the G pole of the N-channel MOS transistor Q2 from being broken down.

Further, in order to control the conduction of the switch unit 20 more conveniently, the control unit 30 includes a switch SW1, a resistor R4, and a resistor R5. One end of the switch SW1 is connected to the positive electrode of the power supply, and the other end is connected to one end of the resistor R4. The other end is connected to one end of the resistor R5, the other end of the resistor R5 is connected to the negative output terminal of the power supply, and the G pole of the N-channel MOS transistor Q2 is connected to the common connection point between the resistor R4 and the resistor R5.

The control unit 30 is designed with two modes, manual and automatic. The manual control is realized by the switch SW1 and the resistor R4, and the automatic control is realized by the resistor R5 connected to the signal output terminal of the automatic control device. Both R4 and R5 are connected to the G pole of the N-channel MOS transistor Q2 of the switch unit 20. When G is extremely high, Q2 is turned on, and when G is extremely low or no level, Q2 is turned off to realize the switch function .

In this way, the switch unit 20 can be controlled manually and automatically, which is simple and convenient, and has a wider application range.

Further, the anti-reverse high-current switch circuit further includes an indicator unit 40, the indicator unit 40 includes LED1 and resistor R3, LED1 and resistor R3 are connected in series, the negative electrode of LED1 is connected to the ground, and one end of resistor R3 is connected to The common connection point between the switch SW1 and the resistor R4 is connected.

The indicating unit 40 is composed of LED1 and R3 connected in series, wherein the negative electrode of LED1 is connected to the ground in the circuit. That is, the S poles of two N-channel MOS transistors. The resistor R3 is connected to the signal control terminal. When it receives a light-emitting start voltage greater than that of LED1, LED1 emits light to indicate that a control signal is injected.

In this way, the instruction unit 40 provides control instructions, provides feedback instructions to the operator, prompts that there is a signal input, and the switch unit 20 is turned on.

Furthermore, the model of the N-channel MOS transistor Q1 is IRFB7430.

The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the various technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, All should be considered as the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the utility model, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the utility model patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the utility model, several modifications and improvements can be made, and these all fall within the protection scope of the utility model. Therefore, the protection scope of the utility model patent should be subject to the appended claims.

Claims

An anti-reverse high-current switch circuit, which is characterized in that it comprises an anti-reverse unit, a switch unit, and a control unit. The signal output ends of the anti-reverse unit and the control unit are connected to the signal input end of the switch unit;

The anti-connection unit includes an N-channel MOS transistor Q1, resistors R1 and R2. One end of the resistor R1 is connected to the positive electrode of the power supply, the other end is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the S of the N-channel MOS transistor Q1. The poles are connected, the G pole of the N-channel MOS transistor Q1 is connected to the common connection point of the resistors R1 and R2, and the D pole of the N-channel MOS transistor Q1 is connected to the negative electrode of the power supply.
The anti-reverse high-current switch circuit according to claim 1, wherein the switch unit includes an N-channel MOS transistor Q2, a resistor R6, and two ends of the resistor R6 are respectively connected to the N-channel MOS transistor Q2. The G pole and S pole are connected.
The high-current switch circuit for preventing reverse connection according to claim 2, wherein the switch unit further comprises an overvoltage protection Z1, and the overvoltage protection Z1 is connected in parallel with the resistor R6.
The anti-reverse high-current switch circuit according to claim 1, wherein the control unit includes a switch SW1, a resistor R4, and a resistor R5. One end of the switch SW1 is connected to the positive electrode of the power supply, and the other end is connected to the resistor R4. One end of the resistor R4 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to the negative output terminal of the power supply, the G pole of the N-channel MOS transistor Q2 is connected to the common connection point between the resistor R4 and the resistor R5 connection.
The anti-reverse high-current switch circuit according to claim 1, characterized in that: the anti-reverse high-current switch circuit further comprises an indicating unit, the indicating unit comprising LED1 and resistor R3, LED1 and resistor R3 is connected in series, the negative electrode of LED1 is connected to the ground, and one end of resistor R3 is connected to the common connection point between switch SW1 and resistor R4.
The anti-reverse high-current switch circuit according to claim 1, wherein the model of the N-channel MOS transistor Q1 is IRFB7430.