Charge/discharge protection circuit with latch circuit for protecting a charge control FET from overheating

A battery pack comprising:

• a secondary battery;
• and
• a charge/discharge protection circuit comprising,
• wherein said charge/discharge protection circuit comprises:
• an overcharge detection circuit which detects an overcharge of said secondary battery connected to said charge/discharge protection circuit and outputs an overcharge detection signal;
• a discharge over-current detection circuit which detects a discharge over-current of said secondary battery and outputs a discharge over-current detection signal;
• a charge control field effect transistor (FET) connected to a charge path of said secondary battery in series so as to cut off a charge current supplied to said secondary battery;
• a discharge control field effect transistor (FET) connected to the charge path of said secondary battery in series so as to cut off a discharge current supplied from said secondary battery;
• a latch circuit which latches the overcharge detection signal output from said overcharge detection circuit and outputs a signal so as to control said charge control FET;
• a first delay circuit which delays the discharge over-current detection signal output from said discharge over-current detection circuit and supplies the delayed discharge over-current detection signal to said discharge control FET;
• and
• a reset circuit which resets said latch circuit so as to turn on said charge control FET when the discharge over-current is detected by said discharge over-current detection circuit and when the overcharge is not detected by said overcharge detection circuit.

An electronic device having a battery pack comprising:

• a secondary battery;
• and
• a charge/discharge protection circuit comprising,
• wherein said charge/discharge protection circuit comprises:
• an overcharge detection circuit which detects an overcharge of said secondary battery connected to said charge/discharge protection circuit and outputs an overcharge detection signal;
• a discharge over-current detection circuit which detects a discharge over-current of said secondary battery and outputs a discharge over-current detection signal;
• a charge control field effect transistor (FET) connected to a charge path of said secondary battery in series so as to cut off a charge current supplied to said secondary battery;
• a discharge control field effect transistor (FET) connected to the charge path of said secondary battery in series so as to cut off a discharge current supplied from said secondary battery;
• a latch circuit which latches the overcharge detection signal output from said overcharge detection circuit and outputs a signal so as to control said charge control FET;
• a first delay circuit which delays the discharge over-current detection signal output from said discharge over-current detection circuit and supplies the delayed discharge over-current detection signal to said discharge control FET;
• and
• a reset circuit which resets said latch circuit so as to turn on said charge control FET when the discharge over-current is detected by said discharge over-current detection circuit and when the overcharge is not detected by said overcharge detection circuit.