Patent ID: 8680867
Filing Date: 2014-03-25
Classification: G01R

Abstract:
1. A battery monitoring circuit that monitors voltages of a plurality of secondary cells connected in series, the battery monitoring circuit comprising: a first switch element with a first end connected to a first terminal, the first terminal connected to a first potential line and connected to a negative electrode of a first secondary cell; a second switch element with a first end connected to a second terminal and a second end connected to a second end of the first switch element, the second terminal connected to a positive electrode of the first secondary cell and a negative electrode of a second secondary cell; a third switch element with a first end connected to a third terminal and a second end connected to the second end of the first switch element, the third terminal connected to a second potential line and connected to a positive electrode of the second secondary cell; a first capacitor with a first end connected to the second end of the first switch element; an operational amplifier with an inverting input terminal connected to a second end of the first capacitor, a non-inverting input terminal connected to a fixed potential, and an output connected to the second end of the first capacitor; an A/D converter configured to perform analog-to-digital conversion of a signal output by the operational amplifier to obtain a digital signal, and to output the digital signal; and a control circuit configured to control an on state and an off state of the first, the second, and the third switch elements and to control operation of the operational amplifier and the A/D converter.