Power supply circuit based on overvoltage protection and direct current reverse connection prevention

Abstract

The utility model discloses a power supply circuit based on overvoltage protection and direct current reverse connection prevention. The power supply circuit comprises a first MOS tube Q1, a triode Q2, a second MOS tube Q3, a power supply, first to seventh resistors R1-R7, a power supply load R8 and a device U1. A reverse connection protection circuit is composed of a first MOS tube Q1, a first resistor R1, a second resistor R2 and a first diode D1, and an overvoltage protection circuit is composed of a third resistor R3, a fourth resistor R4, a fifth resistor R5, a device U1, a sixth resistor R6, a triode Q2, a seventh resistor R7, a second diode D2 and a second MOS tube Q3. According to the utility model, under the conditions of overvoltage and direct current reverse connection, the protection of an electric load can be effectively realized.

Description

Technical Field

[0001] This utility model relates to the field of power supply protection, and in particular to a power supply circuit based on overvoltage protection and DC reverse connection protection. Background Technology

[0002] When using a DC power supply to power electrical loads, the power supply may fluctuate significantly due to the power supply's switching on and off or the influence of extreme external conditions (such as lightning), which may cause overvoltage. In some scenarios, the operator may also mistakenly connect the positive and negative terminals of the power supply, resulting in reverse DC connection.

[0003] Overvoltage and reverse DC connection can pose safety hazards to downstream electrical loads and even damage downstream circuits. Therefore, addressing potential voltage fluctuations during operation and ensuring safe power supply has become an urgent issue to be resolved in power supply processes. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a power supply circuit based on overvoltage protection and DC reverse connection protection, which can effectively protect the electrical load under overvoltage and DC reverse connection conditions.

[0005] The purpose of this utility model is achieved through the following technical solution: a power supply circuit based on overvoltage protection and DC reverse connection prevention, including a first MOSFET Q1, a transistor Q2, a second MOSFET Q3, a power supply, a first resistor R1 to a seventh resistor R7, a power supply load R8, and a device U1;

[0006] The source of the second MOSFET Q3 is connected to the positive terminal of the power supply, and the drain of the second MOSFET Q3 is connected to the first terminal of the power supply load R8.

[0007] The drain of the first MOSFET Q1 is connected to the negative terminal of the power supply, and the source of the first MOSFET Q1 is connected to the second terminal of the power supply load R8; the first terminal of the first resistor R1 is connected to the positive terminal of the power supply, the second terminal of the first resistor R1 is connected to the first terminal of the second resistor R2, and the second terminal of the second resistor is connected to the source of the first MOSFET Q1; the gate of the first MOSFET M1 is connected to the first terminal of the second resistor R2.

[0008] The first end of the third resistor R3 is connected to the positive terminal of the power supply, and the second end of the third resistor R3 is connected to the source of the first MOSFET Q1 through the fourth resistor R4; the first end of the fifth resistor R5 is connected to the positive terminal of the power supply, and the second end of the fifth resistor is connected to the source of the first MOSFET Q1 through device U1, and the reference terminal of device U1 is connected between the third resistor R3 and the fourth resistor R4.

[0009] The emitter of transistor Q2 is connected to the positive terminal of the power supply, the collector of transistor Q2 is connected to the source of first MOSFET Q1 through the seventh resistor R7, and the base of transistor Q2 is connected to the second terminal of fifth resistor R5 through the sixth resistor R6; the collector of transistor Q2 is also connected to the gate of second MOSFET Q3.

[0010] The beneficial effects of this utility model are: it can effectively protect electrical loads under overvoltage and DC reverse connection conditions. Attached Figure Description

[0011] Figure 1 This is a schematic diagram illustrating the principle of this utility model;

[0012] Figure 2 This is a schematic diagram of the device model or parameters in the embodiment. Detailed Implementation

[0013] The technical solution of this utility model is described in further detail below with reference to the accompanying drawings, but the scope of protection of this utility model is not limited to the following description.

[0014] like Figure 1 As shown, a power supply circuit based on overvoltage protection and DC reverse connection protection includes a first MOSFET Q1, a transistor Q2, a second MOSFET Q3, a power supply, a first resistor R1 to a seventh resistor R7, a power supply load R8, and a device U1.

[0015] The source of the second MOSFET Q3 is connected to the positive terminal of the power supply, and the drain of the second MOSFET Q3 is connected to the first terminal of the power supply load R8.

[0016] The drain of the first MOSFET Q1 is connected to the negative terminal of the power supply, and the source of the first MOSFET Q1 is connected to the second terminal of the power supply load R8; the first terminal of the first resistor R1 is connected to the positive terminal of the power supply, the second terminal of the first resistor R1 is connected to the first terminal of the second resistor R2, and the second terminal of the second resistor is connected to the source of the first MOSFET Q1; the gate of the first MOSFET M1 is connected to the first terminal of the second resistor R2.

[0017] The first end of the third resistor R3 is connected to the positive terminal of the power supply, and the second end of the third resistor R3 is connected to the source of the first MOSFET Q1 through the fourth resistor R4; the first end of the fifth resistor R5 is connected to the positive terminal of the power supply, and the second end of the fifth resistor is connected to the source of the first MOSFET Q1 through device U1, and the reference terminal of device U1 is connected between the third resistor R3 and the fourth resistor R4.

[0018] The emitter of transistor Q2 is connected to the positive terminal of the power supply, the collector of transistor Q2 is connected to the source of first MOSFET Q1 through the seventh resistor R7, and the base of transistor Q2 is connected to the second terminal of fifth resistor R5 through the sixth resistor R6; the collector of transistor Q2 is also connected to the gate of second MOSFET Q3.

[0019] The device U1 is a controllable precision voltage regulator, such as a TL431BCD.

[0020] The first MOSFET Q1 is an N-channel MOSFET, and the second MOSFET Q3 is a P-channel MOSFET.

[0021] The transistor Q2 is a PNP transistor. The power supply circuit also includes a first diode D1, the cathode of which is connected to the first end of the second resistor R2, and the anode of the first diode D2 is connected to the second end of the second resistor R2; the power supply circuit also includes a second diode D2, the cathode of which is connected to the emitter of the transistor Q2, and the anode of which is connected to the collector of the transistor Q2.

[0022] In the embodiments of this application, the model or parameters of each device are as follows: Figure 2 As shown, this utility model consists of a reverse connection protection circuit composed of a first MOSFET Q1, a first resistor R1, a second resistor R2, and a first diode D1; and an overvoltage protection circuit composed of a third resistor R3, a fourth resistor R4, a fifth resistor R5, a device U1, a sixth resistor R6, a transistor Q2, a seventh resistor R7, a second diode D2, and a second MOSFET Q3. The overvoltage protection threshold can be adjusted by voltage division using the third resistor R3 and the fourth resistor R4. When the external power supply is correctly connected, the input power supply voltage controls the gate of Q1 through voltage division using R1 and R2, and Q1 is turned on. At this time, the external power supply can be normally applied to the subsequent circuit. D1 mainly limits the gate voltage of Q1 to prevent damage to Q1 under high voltage input. When the external power supply is reversed, the drain of Q1 is connected to the positive power supply, and there is a negative voltage at the gate of Q1. At this time, Q1 is turned off, which is equivalent to the external power supply being disconnected, thereby protecting the subsequent circuit. The external power supply voltage is divided by R3 and R4 and then connected to the reference terminal of U1. When the voltage division value is lower than 2.5V, U1 is cut off, and Q2 is also cut off, meaning Q3 is turned on, which can supply power to the subsequent circuit normally. When the voltage division value is higher than 2.5V, U1 is turned on, the base voltage of Q2 is close to 0V, meaning Q2 is turned on, and Q3 is cut off, thus protecting the subsequent circuit.

[0023] The above description represents a preferred embodiment of this utility model. It should be understood that this utility model is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this utility model should be protected within the scope of the appended claims.

Claims

1. A power supply circuit based on overvoltage protection and DC reverse connection protection, characterized in that: It includes the first MOSFET Q1, the transistor Q2, the second MOSFET Q3, the power supply, the first resistor R1 to the seventh resistor R7, the power supply load R8, and the device U1; The source of the second MOSFET Q3 is connected to the positive terminal of the power supply, and the drain of the second MOSFET Q3 is connected to the first terminal of the power supply load R8. The drain of the first MOSFET Q1 is connected to the negative terminal of the power supply, and the source of the first MOSFET Q1 is connected to the second terminal of the power supply load R8; the first terminal of the first resistor R1 is connected to the positive terminal of the power supply, the second terminal of the first resistor R1 is connected to the first terminal of the second resistor R2, and the second terminal of the second resistor is connected to the source of the first MOSFET Q1; the gate of the first MOSFET M1 is connected to the first terminal of the second resistor R2. The first end of the third resistor R3 is connected to the positive terminal of the power supply, and the second end of the third resistor R3 is connected to the source of the first MOSFET Q1 through the fourth resistor R4. The first end of the fifth resistor R5 is connected to the positive terminal of the power supply, and the second end of the fifth resistor is connected to the source of the first MOS transistor Q1 through device U1. The reference terminal of device U1 is connected between the third resistor R3 and the fourth resistor R4. The emitter of transistor Q2 is connected to the positive terminal of the power supply, the collector of transistor Q2 is connected to the source of first MOSFET Q1 through the seventh resistor R7, and the base of transistor Q2 is connected to the second terminal of fifth resistor R5 through the sixth resistor R6; the collector of transistor Q2 is also connected to the gate of second MOSFET Q3.

2. The power supply circuit based on overvoltage protection and DC reverse connection protection according to claim 1, characterized in that: The device U1 is a controllable precision voltage regulator.

3. A power supply circuit based on overvoltage protection and DC reverse connection protection according to claim 1, characterized in that: The first MOSFET Q1 is an N-channel MOSFET, and the second MOSFET Q3 is a P-channel MOSFET.

4. A power supply circuit based on overvoltage protection and DC reverse connection protection according to claim 1, characterized in that: The transistor Q2 is a PNP transistor.

5. A power supply circuit based on overvoltage protection and DC reverse connection protection according to claim 1, characterized in that: The power supply circuit also includes a first diode D1, the cathode of the first diode D1 is connected to the first end of the second resistor R2, and the anode of the first diode D2 is connected to the second end of the second resistor R2.

6. A power supply circuit based on overvoltage protection and DC reverse connection protection according to claim 1, characterized in that: The power supply circuit also includes a second diode D2, the cathode of which is connected to the emitter of transistor Q2, and the anode of which is connected to the collector of transistor Q2.

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