Patent ID: 7855531

Claim:
A charge and discharge control circuit for controlling a current limiting circuit based on a result obtained by monitoring a voltage of a battery to control charge and discharge of the battery, comprising: an overcharge detection circuit for detecting an overcharge state of the battery by monitoring the voltage between both ends of the battery; an overdischarge detection circuit for detecting an overdischarge state of the battery by monitoring the voltage between the both ends of the battery; an overcurrent detection circuit for detecting one of a charge overcurrent state and a discharge overcurrent state in the battery by monitoring a voltage between both ends of the current limiting circuit; a delay circuit for delaying a detection signal from the overcharge detection circuit, a detection signal from the overdischarge detection circuit, and a detection signal from the overcurrent detection circuit, the delay circuit being provided common to the overcharge detection circuit, the overdischarge detection circuit, and the overcurrent detection circuit; and a logic circuit for generating a signal for controlling the current limiting circuit based on a detection signal outputted from the delay circuit, wherein the charge and discharge control circuit invalidates detection of a charge overcurrent in the overcharge state and detection of a discharge overcurrent in the overdischarge state.