Reverse polarity protection circuit for rechargeable battery and battery protection chip

Abstract

The invention provides a reverse connection protection circuit for a rechargeable battery and a battery protection chip, which includes a capacitor, an ESD protection device, a first MOS switch tube, a switch circuit, a control drive circuit and a load circuit. When the battery is reversely connected to the battery protection chip, the invention adopts a unidirectional conduction isolation type PMOS switch tube to cut off the first reverse current loop, and does not need to adjust the resistance to control the size of the reverse current. The present invention turns off the second MOS switch by controlling the gate potential of the second MOS switch, and at the same time controls the substrate of the second MOS switch to cut off the substrate path of the second MOS switch, thereby realizing the second reverse The current limit or shutdown of the current loop completely solves the problem of large reverse current when the battery and the battery protection chip are connected in reverse, realizes the safe use of the battery, and can effectively improve the reliability and safety of the battery, battery protection chip and load circuit .

Description

technical field [0001] The invention belongs to the field of circuit design, in particular to a reverse connection protection circuit for a rechargeable battery and a battery protection chip. Background technique [0002] An implementation of the battery protection chip with integrated switching power tube on chip is as follows: figure 1 As shown in the embodiment, D1 is an ESD protection device between the chip power supply VDD and the negative electrode GND of the battery core. The battery and the battery protection chip are reversely connected. There are mainly two parallel reverse current loops. The first reverse current loop flows from the positive pole of the battery through the negative pole GND of the battery core into the battery protection chip, flows out from the power supply VDD of the battery protection chip, and then passes through the limiting circuit. The current resistance R1 returns to the negative pole of the battery; the second loop flows from the positi...

AI Technical Summary

Problems solved by technology

[0005] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a reverse connection protection circuit for a rechargeable battery and a battery protection chip, which is used to solve the problem of large reverse polarity caused by the inability to control or shut off the loop current in the prior art. current problem

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