Secondary overvoltage protection circuit for lithium battery protection boards

Abstract

The invention discloses a secondary overvoltage protection circuit for lithium battery protection boards. The secondary overvoltage protection circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a control chip, a power supply and a field-effect transistor. The control chip is used with a three-end thermal fuse, when the voltage detected by the control chip is more than or equal to 4.45V, the OUT end outputs high level to enable a drain and a source of the field-effect transistor to be connected, the three-end thermal fuse is forced to be subjected to pull-down fusing at the moment, secondary overvoltage protection is achieved, and accidents are avoided.

Description

technical field [0001] The invention relates to a secondary protection circuit, in particular to a secondary overvoltage protection circuit for a lithium battery protection board. Background technique [0002] Usually, the intelligent power management lithium battery protection board design consists of a power management chip and a protection chip or a chip integrated with the two, a field effect transistor and a peripheral resistance device, a fuse or a PTC, etc.; the protection chip is generally used as a primary protection , such as over-charge protection, over-discharge protection, over-temperature protection, over-current protection, short-circuit protection, etc.; fuses or PTCs are used as secondary protection, such as over-temperature protection, over-current protection, and short-circuit protection. Traditional lithium battery protection boards The main design of the battery is not designed with an overvoltage secondary protection function, so that the use of the bat...

AI Technical Summary

Problems solved by technology

[0002] Usually, the intelligent power management lithium battery protection board design consists of a power management chip and a protection chip or a chip integrated with the two, a field effect transistor and a peripheral resistance device, a fuse or a PTC, etc.; the protection chip is generally used as a primary protection , such as over-charge protection, over-discharge protection, over-temperature protection, over-current protection, short-circuit protection, etc.; fuses or PTCs are used as secondary protection, such as over-temperature protection, over-current protection, and short-circuit protection. Traditional lithium battery protection boards The main design of the battery is not designed with the overvoltage secondary protection function, so that the use of the battery may be dangerous due to the failure of the overvoltage protection during use.

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