Patent ID: 7924016
Filing Date: 2011-04-12
Classification: G01R

Abstract:
1. A voltage measuring device comprising: a capacitor sequentially connected to a plurality of unit cells connected in series, and charged in positive and negative polarities depending on the unit cells; a voltage measuring unit for measuring a voltage across the capacitor, said voltage measuring unit having a first and a second input terminal, wherein a differential voltage between the first and the second input terminals determines a voltage across the capacitor; a pair of first switches, each switch having a controllable connecting means for either connecting or not connecting a first terminal and a second terminal of the switch, wherein, when the connecting means is not connecting, the first terminals of the first switches are respectively connected to first and second terminals of the capacitor and the second terminals of the first switches are respectively connected to the first and second input terminals of the voltage measuring unit; a pair of second switches, each switch having a controllable connecting means for either connecting or not connecting a first terminal and a second terminal of the switch, wherein, when the connecting means is not connecting, the first terminals of the second switches are respectively connected to the first and the second input terminals and the second terminals of the second switches are connected to a ground; a first switching controller for controlling the first and second switches so that when a first terminal of the capacitor is positive charged, while a second terminal of the capacitor is grounded, at least the first terminal of the capacitor is connected to one of the input terminals; a second switching controller for controlling the first and second switches so that when the second terminal of the capacitor is positive charged, while the first terminal is grounded, at least the second terminal of the capacitor is connected to one of the input terminals.