Charge/discharge control circuit and battery apparatus having the same

A charge/discharge control circuit which controls charge/discharge of a secondary cell, comprising:

• a positive power supply terminal and a negative power supply terminal configured to monitor a voltage of the secondary cell;
• an external negative voltage input terminal configured to receive a voltage of an external negative terminal to which a negative electrode of a load is connected;
• a discharge control terminal configured to output a discharge control signal to a discharge control FET;
• an overdischarge detection circuit configured to output an overdischarge detection signal at detection of overdischarge of the secondary cell according to a voltage of the positive power supply terminal;
• a control circuit configured to output an overdischarge state signal and the discharge control signal, based on the overdischarge detection signal;
• an overdischarge latch circuit configured to output an overdischarge latch signal, based on the overdischarge state signal and the voltage of the external negative voltage input terminal;
• a logic circuit configured to receive the overdischarge detection signal and the overdischarge latch signal and output the overdischarge detection signal to the control circuit while receiving the overdischarge latch signal;
• and
• a pull-up detection circuit configured to monitor the voltage of the external negative voltage input terminal and thereby output a pull-up signal,
• wherein the control circuit outputs a power-down control signal based on the pull-up signal input to the control circuit, and
• wherein the overdischarge detection circuit enters a power-down state based on one of the power-down control signal and the overdischarge latch signal.