Abstract: In a charging and discharging control circuit that controls the charging and discharging operation of a secondary battery and a charging type power supply device for the secondary battery which includes the charging and discharging control circuit therein, there is provided a charging and discharging control circuit that enters a test mode where the delay time of the internal control circuit is shortened when a voltage equal to or higher than a regulated voltage is applied to the charger connection terminal of a charging type power supply device.

Abstract: When overdischarging or overcurrent of a rechargeable battery pack is detected, the output voltage current and output current between VDD and VSS of the pack become zero. In this case, a device, or a load, connected with the battery pack may lose data or malfunction. In a rechargeable battery pack 1, if a voltage V1 across a secondary battery decreases below a certain detection voltage V2, a pre-end signal output circuit 5 produces a pre-end output signal, which is made to persist until an overcharging/overdischarging-and-overcurrent control circuit 3 senses that the secondary battery voltage V1 has decreased below an overdischarging detection voltage V3. The output signal from the control circuit 3 causes the switch circuit 4 to stop discharging of the secondary battery. Therefore, the device, or load, can save data or otherwise operate.