Patent ID: 7772805

Claim:
A charge/discharge protection circuit that protects a secondary battery from overcharge, over-discharge, charge over-current, and discharge over-current, said charge/discharge protection circuit comprising: an overcharge detection circuit; an over-discharge detection circuit; a charge over-current detection circuit; a discharge over-current detection circuit; a charge control FET that is turned off when overcharge is detected by the overcharge detection circuit and when charge over-current is detected by the charge over-current detection circuit; a discharge control FET that is turned off when over-discharge is detected by the over-discharge detection circuit and when discharge over-current is detected by the discharge over-current detection circuit; and a charger connection recovery circuit that controls on/off operations of the discharge control FET such that when connection with a charger is established at a time over-discharge is detected and the discharge control FET is turned off, the discharge control FET is forcefully turned on after an over-discharge recovery delay time elapses, wherein the discharge control FET is turned off after an over-discharge detection delay time elapses from the time the discharge control FET is forcefully turned on.