BATTERY-MONITORING DEVICE

摘要

The purpose of the present invention is to measure battery cell voltage with good precision even when considerable ripple voltage is superimposed on the battery cell voltage. A power circuit (13) generates and feeds a drive voltage (18) for driving switching elements (110p, 111p, 111m, 112m) of a selection circuit (11) to the selection circuit (11) on the basis of a reference voltage (17) inputted from a battery pack (2). The reference voltage (17) is inputted from the battery pack (2) to the power circuit (13) via a detection filter circuit (120). The time constant of the pathway in which the reference voltage (17) is inputted from the battery pack (2) to the power circuit (13) and the time constant of the detection filter circuits (120 to 122) are substantially equal.