Over-voltage and over-current hardware protection circuit and DC power supply circuit

Abstract

The invention relates to an over-voltage and over-current hardware protection circuit which mates with a main circuit of which the power is supplied by a DC power supply; the protection circuit comprises a current signal detection unit, a voltage signal detection unit, a comparison unit, a trigger flip-flop unit and a blocking protection unit; the current signal detection unit samples, rectifies,amplifies and compares the working current of the main circuit so as to output a first level signal; the voltage signal detection unit samples, filters, amplifies and compares the working voltage of the main circuit so as to output a second level signal; the comparison unit outputs a trigger signal when the first level signal or the second level signal is low level; the trigger flip-flop unit flip-flops the trigger signal so as to produce and output a driving signal; and the blocking protection unit controls to cut off the main circuit when receiving the driving signal so as to cut off the DCpower supply. The invention also relates to a DC power supply circuit. When the main circuit fails, the over-voltage and over-current hardware protection circuit can quickly respond in microsecond, so that the DC power supply and the main circuit are quickly cut off so as to protect power devices in the main circuit.

Description

Technical field [0001] The invention relates to the technical field of power supply protection, and more specifically, to an overvoltage and overcurrent hardware protection circuit and a DC power supply circuit. Background technique [0002] At present, the shutdown of the DC power supply is mainly based on two methods, the first is the large voltage detection and shutdown method, and the second is the large current detection and shutdown method, which are described below: [0003] The first, the high-voltage detection shutdown method, connects a mutual inductance coil in parallel at both ends of the DC power supply. First, a stable DC voltage is obtained through a rectifier and filter circuit based on the fixed turns ratio of the mutual inductance coil, and then an operational amplifier is used for this. The stable DC voltage is attenuated and sent to the MCU. The MCU compares the attenuated stable DC voltage with a preset voltage threshold, and judges whether the attenuated stabl...

AI Technical Summary

Problems solved by technology

[0008] The technical problem to be solved by the present invention is that the large voltage detection shutdown mode and the large current detection shutdown mode of the above-mentioned DC power supply in the prior art are limited by the speed of the MCU, and the breakdown of the power device to the large current and large voltage The time is very short so that the defect of power device protection cannot be well realized, and an overvoltage and overcurrent hardware protection circuit and a DC power supply circuit are provided

Images