Patent ID: 7215096

Claim:
A battery pack with a charge control function, said battery pack comprising: an overdischarge control circuit for detecting an overdischarge mode of a secondary battery and supplying an overdischarge detection signal to a discharge control switch when the overdischarge mode is detected; an overcharge control circuit for detecting an overcharge mode of the secondary battery and supplying an overcharge detection signal to a charge control switch when the overcharge mode is detected; and a charge control circuit for performing charge control of the secondary battery by controlling the charge control switch; wherein the charge control circuit includes a constant-current control circuit, a constant-voltage control circuit, and a primary overvoltage detecting circuit; wherein the constant-current control circuit controls the charge control switch so as to keep a potential difference across a current-detecting resistor at a predetermined value in order to charge the battery pack at a constant current; wherein the constant-voltage control circuit detects a battery voltage of the secondary battery and controls the charge control switch so that the battery voltage does not exceed a predetermined voltage in order to charge the battery pack; and wherein the primary overvoltage detection circuit detects a primary voltage, and the primary over voltage detection circuit turns off the charge control switch and stops charging when the primary voltage is an overvoltage.