Charge / discharge protection circuit and battery pack having the charge / discharge protection circuit

摘要

A charge/discharge protection circuit of the present invention includes a first terminal to which a negative electrode of a charger is connected and an internal detector unit which has an input connected to the first terminal, and prevents the variation of the threshold voltage of the input transistors in a short-circuit detector unit and in an overcurrent detector unit when the improper charger is connected to the battery for a long time. An improper charger detector unit outputs a detection signal when an improper charger is connected to the battery pack, in response to a voltage supplied to the first terminal by the improper charger. A connection cutoff unit cuts off, when the detection signal is output by the improper charger detector unit, the connection between the internal detector unit input and the first terminal, so that, when the improper charger is connected to the battery pack, a voltage of the input of the internal detector unit is avoided from being lower than a voltage of a second terminal to which a negative electrode of the battery is connected.