Detection circuit for serial lithium battery pack protection chip

The invention belongs to the field of integrated circuits, and specifically relates to a detection circuit for a serial lithium battery pack protection chip. The circuit comprises a cascading overvoltage detection circuit and a cascading undervoltage detection circuit. The cascading overvoltage detection circuit comprises an overvoltage current comparison detection circuit, an overvoltage hysteresis comparison circuit, and an overvoltage logic control circuit. The cascading undervoltage detection circuit comprises an undervoltage current comparison detection circuit, an undervoltage hysteresis comparison circuit, and an undervoltage logic control circuit. The overvoltage current comparison detection circuit receives an overvoltage detection signal outputted by a chip at the next stage, and is connected with the overvoltage hysteresis comparison circuit. The overvoltage logic control circuit receives an output signal of the undervoltage hysteresis comparison circuit, and outputs an overvoltage detection signal at the same stage. Through current comparison, the circuit solves a problem that a high-voltage MOS tube is limited in withstand voltage, and achieves the communication of two or more battery protection chips during cascading operation.