Voltage self-following anti-backflow circuit

Abstract

The invention relates to a voltage self-following anti-backflow circuit, which comprises N diodes, a PMOS tube and a resistor, the voltage input end of the voltage self-following anti-backflow circuit is connected with the anodes of the N diodes and the drain electrode of the PMOS tube, the voltage output end of the voltage self-following anti-backflow circuit is connected with the cathodes of the N diodes and the source electrode of the PMOS tube, and the grid electrode of the PMOS tube is connected with an external control signal input end. The external control signal input end can output high and low levels to control the on-off of the PMOS tube; one end of the resistor is connected with the source electrode of the PMOS tube, and the other end of the resistor is connected with the grid electrode of the PMOS tube; and the number N of the N diodes is an integer greater than 0. The circuit is applied to a constant-current charging and boost discharging circuit of a battery or a super-capacitor module, reverse charging caused by the fact that leakage current exceeds the standard is prevented, and constant-current charging cut-off voltage and boost discharging voltage can be accurately controlled.

Description

technical field [0001] The invention relates to the technical fields of instruments and meters and intelligent distribution network, in particular to a voltage self-following anti-backfeed circuit. Background technique [0002] In the process of charging the battery or supercapacitor module with constant current, if the input terminal of the constant current DC / DC chip is powered off, and there is a high voltage at the output terminal at this time, there will be a gap between the output of the constant current DC / DC chip and the input. Higher leakage current, if the leakage current is light, it will cause the constant current DC / DC chip to not work normally, such as hiccup-type repeated startup, input and output straight-through, etc., which may lead to abnormal high temperature of the constant current DC / DC chip, chip failure, etc. Burn out, and even the battery or supercapacitor module explodes due to an instant short circuit. Therefore, an anti-backfeed circuit must be i...

AI Technical Summary

Problems solved by technology

The circuit uses two MOS transistors to realize the anti-backfeed and the voltage at both ends of the anti-backfeed circuit is equal, but because the combination of the two MOS transistors requires that the gate level bound together must be a certain level state, it is not allowed Continuous change

If the voltage at both ends of the anti-backfeed circuit changes continuously, the circuit will not work

In the process of constant current charging, the output voltage of the constant current DC / DC chip increases with the continuous increase of the voltage of the battery or supercapacitor module, so the circuit cannot realize anti-backfeed and no voltage during constant current charging. loss of function

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