A kind of overcurrent protection circuit of DC electronic contactor

Abstract

The invention discloses an overcurrent protection circuit for a DC electronic contactor. The drain of an NMOS switch tube is connected to the positive pole of a DC power supply, and the source is connected to the negative pole of the DC power supply through a load; the control signal of a single-chip microcomputer is input to the grid of the NMOS switch tube through a driving circuit. Multiple NMOS switch tubes are connected in parallel, the drain of the NMOS switch tube is also connected to the same direction input terminal of the differential amplifier through the relay protection circuit and the differential resistance, and the source is also connected to the reverse input of the differential amplifier through the equivalent resistance of the relay coil and the differential resistance terminal, and the output terminal of the differential amplifier is connected to the AD conversion module of the single-chip microcomputer. The driving signal controls the NMOS switch to turn on, and the overcurrent protection circuit samples the voltage across the drain and source of the NMOS switch in real time. The design of the overcurrent protection circuit is simple, and the circuit can not only reduce the use cost, but also improve the reliability and stability of the circuit during operation.

Description

technical field [0001] The invention relates to the field of circuit control, in particular to an overcurrent protection circuit of a DC electronic contactor. Background technique [0002] DC power supplies are widely used in various fields of people's production and life, and common applications include electric vehicles, communications, energy, and computer room servers. In a DC power supply circuit composed of a DC power supply and a load, a mechanical contactor switch is usually used to control the on-off of the power supply circuit. However, mechanical contactors are expensive, and when used with high current, they are noisy and prone to arc damage, resulting in high cost of use. In addition, when mechanically switching, there will be pulse spike noise conduction into the surrounding power grid, polluting the grid environment. [0003] In order to solve the above problems, the patent number CN203071900U proposes an electronic contactor, but this patent does not mentio...

AI Technical Summary

Problems solved by technology

[0004] The invention provides an overcurrent protection circuit of a DC electronic contactor, aiming to solve the problem of overcurrent damage to the NMOS switch tube caused by the sudden change in load of the electronic contactor

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