| 摘要 |
PURPOSE:To reduce the current consumption of a battery for measurement and to eliminate the adjustment work of each circuit part, by simple constitution such that voltage is connected to a battery only at the time of voltage and compared with a preliminarily stored value as an initial voltage value. CONSTITUTION:An integrator circuit consisting of a resistor 12 and a condenser 13 is connected to the switch 12 connected to a battery 9 and a switch 11 is connected between the connection point of the resistor 12 and the switch 10 and the earth and turned OFF and ON by turning the switch ON and OFF. When the output level of the integrator circuit reaches a predetermined value or more, the output of a comparator 15 changes to be applied to a microcomputer (MPU) 1. MPU 1 measures the time before the output of the comparator 15 is turned ON after the ON-control of the switch 10 on the basis of a microprogram to store the same in RAM 3 as the initial voltage value of the battery and subsequently compares the value measured by turning the controlled switch 10 ON with the value of RAM 3 to detect the voltage of the battery.
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