PULSE AMPLITUDE COMPARISON CIRCUIT CORRECTING INITIAL DEVIATION

PURPOSE:To discriminate deterioration in a battery by correcting the amplitude of two input pulse amplitudes having an initial deviation and detecting the change in the amplitude produced later to check the state of pulse change of a terminal voltage of the battery caused in charging or discharging, e.g., two sets of secondary batteries at the same time. CONSTITUTION:A microcomputer 10 decreases little by little a voltage of other input terminal through the 1st switch means 6 in a direction canceling a bias voltage fed to one input terminal of a comparator 9 and finds out a point where the peak of two input pulses is coincident to correct the deviation of the pulse amplitude. Since the two input pules are compared while the common mode voltage at two input terminals is decreased alternately by a prescribed value, one input pulse is being changed and whether or not the amplitude exceeds the said prescribed value is detected.