Patent ID: 8129948

Claim:
A protective circuit for a secondary battery pack having a plurality of batteries, comprising: a sampling circuit that includes a sequential pulse generator to generate gating pulses for selecting one or more of the plurality of batteries for inspection, and to generate sampling pulses for inspecting the selected batteries at predetermined time intervals, wherein the width of the sampling pulses are set at ½ to ¾ of a width of corresponding gating pulses; a selection circuit to receive said gating pulses and select a battery in the battery pack; a reference voltage source providing one or more reference levels; a plurality of voltage comparators each receiving one of the reference levels to compare with the level of the selected battery and generating one or more compared levels; a battery status decision circuit connected to the comparators generating control signals as a function of the compared levels; and a battery charging/discharging control circuit for controlling the charging or discharging of the selected battery in response to the control signals.