This invention discloses a charging/discharging protective circuit for a
secondary battery pack, having an over-charging/discharging voltage
comparator, a reference voltage source and a battery status decision
circuit. There is also a sampling circuit having a sequential pulse
generator for generating pulses for selecting one of the batteries in the
battery pack for testing purposes. The pulse generator provides M-channel
gating pulses to the selection circuit of the battery under test and
provides sampling pulses to the over-charging/discharging voltage
comparators. The reference voltage source has a regulated output circuit.
This invention uses time division inspection methods to provide a
cost-effective solution for inspecting batteries in a battery pack.