| 摘要 |
PROBLEM TO BE SOLVED: To detect the voltage of a battery inexpensively and with high accuracy. SOLUTION: A battery voltage detection circuit 10 includes: a first switch circuit for applying voltage of one terminal of a battery to the other end of a first capacitor C1 and applying voltage of the other terminal of the battery to the other end of a third capacity C3; an energizing circuit for energizing a transient current flowing when the voltage of one terminal of the battery is applied to the other end of the first capacitor; a second switch circuit for electrically disconnecting one input terminal of an operational amplifier from one end of the first capacitor during flowing of the transient current, and electrically connecting the one input terminal of the operational amplifier to the one end of the first capacitor after a transient current flows; and a third switch circuit for applying voltage of the other terminal of the battery to the other end of the circuit capacitor after the one input terminal of the operational amplifier and the one end of the first capacitor are electrically connected to each other, wherein the voltage of the battery is detected based on the voltage of the output terminal of the operational amplifier after the voltage of the other terminal of the battery is applied to the other end of the first capacitor. COPYRIGHT: (C)2009,JPO&INPIT
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