Overvoltage and overcurrent protection circuit with state holding function

Abstract

The invention discloses an overvoltage and overcurrent protection circuit with the state holding function, comprising an overcurrent detection circuit and an overvoltage detection circuit. The overvoltage and overcurrent protection circuit with the state holding function is characterized by further comprising a triggering circuit, a state holding circuit and a switching circuit; the triggering circuit receives the control signals outputted by the overcurrent detection circuit and the overvoltage detection circuit; when the overvoltage signal appears, the overvoltage detection circuit outputs the control signal to control the switching circuit to switch off, and when the overcurrent signal appears, the overcurrent detection circuit outputs the control signal to control the switching circuit to switch off; the switching circuit is connected between the power output and the protection circuit output; the control end of the switching circuit receives the control signals outputted by the triggering circuit and the state holding circuit; the switching circuit is started by the state holding function to switch on; and when the overvoltage and overcurrent signal appears, the triggering circuit controls the switching circuit to switch off, and the state holding circuit keeps the switching circuit in the switching-off state.

Description

technical field [0001] The invention relates to a protection circuit, in particular to an overvoltage and overcurrent protection circuit with the function of maintaining state. Background technique [0002] Whether it is a chip, a module, or a complete machine, in order to improve the reliability of the product, most products need to go through an aging process before leaving the factory, and some products also need to undergo a life test. However, the regulated power supply used in burn-in or life test has a large working current, high temperature, and long burn-in time. If overvoltage and over-current occur during the burn-in process, the mild one will cause the circuit to burn out, and the severe one will cause a major accident. Therefore, it is very necessary to carry out overvoltage and overcurrent protection on aging circuits. [0003] At present, there are many overvoltage and overcurrent protection circuits in the market, but due to different use occasions and purpo...

AI Technical Summary

Problems solved by technology

Since this circuit uses N-channel MOSFET, it does not include an overcurrent protection circuit, and it cannot continuously cut off the current loop under overvoltage conditions, so it is not suitable as a protection circuit for burn-in

[0005] In addition, there are fuses and thyristors on the market to achieve overvoltage and overcurrent protection. Since the fuses used have relatively large current specifications, many varieties, and different sizes, it is necessary to make a variety of PCB solutions according to the size of the fuse; at the same time After the fuse is blown, it cannot be recovered because it cannot be reused. When dealing with the situation on site, a sufficient number of fuses must be prepared. It is inconvenient to debug the threshold voltage. Although the initial cost of the circuit is low, the current specification of the fuse is relatively large, and the price is also high. Not low, the later maintenance cost is high

[0006] Therefore, at present, there is no special protection circuit suitable for burn-in in the domestic and international markets, and the protection can only be achieved by the current limiting function of the power supply itself. The output voltage is unstable and the current cannot be adjusted accurately

In addition, the aging circuit has contact resistance and resistance of the circuit itself. The output current usually ranges from a few amperes to tens of amperes. cause a chain reaction

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