Patent ID: 8786248

Claim:
A flying capacitor type voltage detecting circuit comprising: a flying capacitor; a first switch circuit that allows each of plural electric cells that are connected in series constituting an assembled battery to individually charge the flying capacitor, so that polarity of voltage across electrodes of the flying capacitor when charged by a first one of the plural electric cells is opposite to polarity of voltage across the electrodes of the flying capacitor when charged by a second one of the plural electric cells, wherein the second one of the plural electric cells is adjacent to the first one of the plural electric cells; a second switch circuit that discharges the flying capacitor; an output circuit that outputs a signal depending on the voltage across the flying capacitor; a first shielding section that is arranged around the electrodes of the flying capacitor to substantially equalize parasitic capacitances between the first shielding section and each of the electrodes; and an electric potential difference controlling circuit that substantially equalizes voltage between one of the electrodes of the flying capacitor and the first shielding section when the flying capacitor is charged, and equalizes voltage between another one of the electrodes of the flying capacitor and the first shielding section when the flying capacitor is discharged.