Patent ID: 8749935

Claim:
A protection circuit for lithium-ion battery comprising: a sample circuit to sample battery voltage of the lithium-ion battery as a sample voltage and outputting the sample voltage; a switch circuit comprising a first switch comprising two first connection terminals and a first control terminal, the first switch being configured for connecting the two first connection terminals when the control terminal receives a high logic level and disconnecting the two first connection terminals when the control terminal receives a low logic level, wherein one of the first connection terminals is connected to the lithium-ion battery through a first current-limiting resistor to receive a battery voltage and is connected to an output terminal of the switch circuit, the other first connection terminal is grounded, and the first control terminal is connected to the sample circuit to receive the sample voltage and is grounded through a bypass capacitor, the output terminal outputs a logic low level as a turn-on signal and a logic high level as a turn-off signal of the lithium-ion battery; and an inverting circuit, wherein the inverting circuit comprises a second switch, the second switch comprises two second connection terminals and a second control terminal, the second switch is configured for connecting the two second connection terminals when the second control terminal receives a logic high level and disconnecting the two second connection terminals when the second control terminal receives a logic low level, the second control terminal is connected to the output terminal, one of the second connection terminals is connected to the lithium battery to receive the battery voltage through a second current-limiting resistor and functions as a control terminal of the protection circuit, and the other second connection terminal is grounded; and wherein when the output terminal outputs the high logic level, the second switch is turned on, and the control terminal outputs the logic low level as the turn-on signal of the lithium-ion battery, and when the output terminal outputs the logic low level, the second switch is turned off, and the control terminal outputs the logic high level as the turn-off signal of the lithium-ion battery.