A power supply short circuit protection circuit

Abstract

The utility model discloses a power supply prevents short circuit protection circuit, is composed of MOS pipe Q1, triode Q2, resistance R1 and resistance R2, power input terminal VIN is connected with MOS pipe Q1's S pole, triode Q2's E pole respectively, MOS pipe Q1's G pole is connected with triode Q2's C pole, resistance R2 respectively, the other end of resistance R2 is connected to ground, MOS pipe Q1's D pole is connected with resistance R1, load respectively, the other end of resistance R1 is connected to triode Q2's B pole, when the load short circuit, the utility model discloses can cut off load power supply rapidly, prevents the large current damage power supply and even induces the danger, compared with the scheme of traditional use self -recovery insurance, the utility model utilizes MOS pipe on -off control load and power supply's connection, avoided the phenomenon that circuit frequently on -off under the situation that short circuit fault has not been ruled out, avoided the security risk also improved the service life of device, improved the stability of circuit.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, and in particular to a power supply short-circuit protection circuit. Background Technology

[0002] A load short circuit refers to a fault in which the two ends of a load in a circuit are directly connected by a conductor with extremely low resistance (such as a wire), causing current to bypass the load and form a direct loop. Its effects mainly include the following: 1. A sharp increase in current; 2. Damage to power supply equipment; 3. Burning out of lines or components; 4. Causing safety accidents; 5. Affecting the normal operation of other circuits; 6. Triggering protection mechanisms. Currently, simple short-circuit protection circuits typically use fuses to disconnect the power supply from the load, such as... Figure 2 As shown, a fuse is connected in series between the power interface and the load. When the load is short-circuited, the current increases sharply, causing the fuse to blow and thus providing protection. However, if a one-time fuse is used, the resistance wire needs to be replaced after short-circuit protection, increasing labor costs. If a resettable fuse is used, although maintenance costs can be reduced, frequent switching of the resettable fuse may occur if the load fault cannot be cleared in time, affecting power supply safety. Furthermore, prolonged frequent switching can degrade the performance of the resettable fuse or even cause it to fail completely. Therefore, there is an urgent need to develop a power supply short-circuit protection circuit to solve the above technical problems.

[0003] In view of the above, this utility model is hereby proposed. Utility Model Content

[0004] The purpose of this invention is to provide a power supply short-circuit protection circuit that can quickly cut off the power supply to the load when a short circuit occurs, preventing large currents from damaging the power supply or even inducing danger. Compared with the traditional solution using a self-resetting fuse, this invention uses a MOSFET to control the connection between the load and the power supply, avoiding the phenomenon of frequent circuit switching when the short circuit fault has not been eliminated. This avoids safety hazards, improves the service life of the device, and enhances the stability of the circuit. It has broad application prospects and is conducive to widespread application.

[0005] To achieve the above objectives, this utility model provides a power supply short-circuit protection circuit, which consists of a MOSFET Q1, a transistor Q2, resistors R1 and R2. The power input terminal VIN is connected to the source (S) of MOSFET Q1 and the emitter (E) of transistor Q2. The gate (G) of MOSFET Q1 is connected to the collector (C) of transistor Q2 and resistor R2. The other end of resistor R2 is connected to ground. The drain (D) of MOSFET Q1 is connected to resistor R1 and the load. The other end of resistor R1 is connected to the base (B) of transistor Q2. When the load is normal, MOSFET Q1 is turned on, transistor Q2 is turned off, and the load operates normally. When a short circuit occurs in the load, transistor Q2 is turned on, the gate (G) level of MOSFET Q1 is pulled high, and MOSFET Q1 is turned off, thereby cutting off the power supply to the load and protecting the power supply from short circuits.

[0006] Preferably, the MOS transistor Q1 is a P-channel MOS transistor.

[0007] Preferably, the transistor Q2 is a PNP transistor.

[0008] Preferably, the resistance value of resistor R2 satisfies the following condition: the ratio of the power input voltage VIN to the resistance R2 is less than the maximum allowable value of Ic of transistor Q2.

[0009] The power supply short-circuit protection circuit provided by this utility model has the following beneficial effects.

[0010] 1. When a short circuit occurs in the load, this utility model can quickly cut off the power supply to the load, preventing large current from damaging the power supply or even inducing danger.

[0011] 2. Compared with the traditional solution using self-resetting fuses, this utility model uses the on / off control of MOSFETs to control the connection between the load and the power supply, avoiding the phenomenon of frequent circuit switching when the short circuit fault has not been eliminated. This not only avoids safety hazards but also improves the service life of the device and enhances the stability of the circuit. Attached Figure Description

[0012] Figure 1 A circuit diagram of a power supply short-circuit protection circuit provided by this utility model.

[0013] Figure 2 This is a circuit diagram of a short-circuit protection circuit in the prior art. Detailed Implementation

[0014] The present invention will be further described below with reference to specific embodiments and accompanying drawings to help understand the content of the present invention.

[0015] like Figure 1The diagram shown is a circuit diagram of a power supply short-circuit protection circuit provided by this utility model. This power supply short-circuit protection circuit consists of a MOSFET Q1, a transistor Q2, resistors R1 and R2. The power input terminal VIN is connected to the source (S) of MOSFET Q1 and the emitter (E) of transistor Q2. The gate (G) of MOSFET Q1 is connected to the collector (C) of transistor Q2 and resistor R2. The other end of resistor R2 is connected to ground. The drain (D) of MOSFET Q1 is connected to resistor R1 and the load. The other end of resistor R1 is connected to the base (B) of transistor Q2. Preferably, MOSFET Q1 is a P-channel MOSFET. Transistor Q2 is a PNP transistor. The resistance value of resistor R2 satisfies the condition that the ratio of the power input voltage VIN to the resistance of resistor R2 is less than the maximum allowable Ic value of transistor Q2.

[0016] The working principle of this utility model is as follows: When the load is normal, MOSFET Q1 is turned on and transistor Q2 is turned off, and the load works normally. When the load is short-circuited, transistor Q2 is turned on, the gate level of MOSFET Q1 is pulled high, and MOSFET Q1 is turned off, thereby cutting off the power supply to the load and playing the role of protecting the power supply from short circuit.

[0017] When a short circuit occurs in the load, this invention can quickly cut off the power supply to the load, preventing large currents from damaging the power supply or even inducing danger. Compared with the traditional solution using a self-resetting fuse, this invention uses the switching of a MOSFET to control the connection between the load and the power supply, avoiding the phenomenon of frequent switching of the circuit when the short circuit fault has not been eliminated. This avoids safety hazards and also improves the service life of the device and the stability of the circuit.

[0018] This article uses specific examples to illustrate the inventive concept in detail. The description of the above embodiments is only for the purpose of helping to understand the core idea of ​​this utility model. It should be noted that any obvious modifications, equivalent substitutions or other improvements made by those skilled in the art without departing from the inventive concept should be included within the protection scope of this utility model.

Claims

1. A short-circuit protection circuit for a power supply, characterized by comprising: It consists of a MOSFET Q1, a transistor Q2, and resistors R1 and R2. The power input terminal VIN is connected to the source (S) of MOSFET Q1 and the emitter (E) of transistor Q2. The gate (G) of MOSFET Q1 is connected to the collector (C) of transistor Q2 and resistor R2. The other end of resistor R2 is connected to ground. The drain (D) of MOSFET Q1 is connected to resistor R1 and the load. The other end of resistor R1 is connected to the base (B) of transistor Q2. When the load is normal, MOSFET Q1 is turned on and transistor Q2 is turned off, and the load works normally. When the load is short-circuited, transistor Q2 is turned on, the gate (G) level of MOSFET Q1 is pulled high, and MOSFET Q1 is turned off, thereby cutting off the power supply to the load and protecting the power supply from short circuits.

2. The short-circuit protection circuit according to claim 1, wherein The MOSFET Q1 is a P-channel MOSFET.

3. The short circuit protection circuit according to claim 1, wherein The transistor Q2 is a PNP type transistor.

4. The short circuit protection circuit according to claim 1, wherein The resistance value of the resistor R2 satisfies the following condition: the ratio of the voltage at the power input terminal VIN to the resistance of R2 is less than the maximum allowable value of Ic of the transistor Q2.

Images