Patent ID: 7656164
Filing Date: 2010-02-02
Classification: G01R

Abstract:
1. A method of voltage measurement of a voltage supply comprising the steps of: charging a capacitor with a charging unit for a prescribed period of time of charging; measuring a charge of the capacitor charged with a measuring unit for a prescribed period of time of charge measurement; supplying a reference voltage of voltage measurement from a reference voltage supply circuit connected between the capacitor and a microcomputer during the prescribed period of time of charge measurement; supplying a voltage of a correction measurement voltage supply from a correction measurement circuit connected between the capacitor and the reference voltage supply circuit during the prescribed period of time of charging; and calculating a voltage of the voltage supply from a measurement value of the charge, wherein the voltage of the correction measurement voltage supply is supplied to the measuring unit and is measured during the prescribed period of time of charging, a correction value is calculated from a difference between a measurement value and a theoretical value of the voltage of the correction measurement voltage supply, and the correction value is subtracted from the measurement value of the charge during the prescribed period of time of charge measurement for calculating the voltage of the voltage supply.