| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that, when a resistor used for voltage division in order to monitor a boosted voltage is broken down and a voltage dividing ratio is changed, since the boosted voltage does not become a preset voltage, characteristics of a circuit using the boosted voltage are not presented, the problem that, when an input terminal of a boosted voltage detection section is short-circuited to GND by a conductive foreign substance or the like, 0V is determined in voltage detection, control is performed to enlarge the boosted voltage and finally, an electronic component used in the circuit breaks down over voltage resistance of the electronic component, and the problem that there is a method of stopping a boosting operation by detecting the boosted voltage in a CPU in order to detect such failures, but when such failures occur, boosting is performed up to a voltage exceeding the voltage resistance of the component within a short time because of improvement in a boosting capability in the recent years, and when detection is attained by the CPU, it is necessary to monitor the boosted voltage in a short cycle, thereby increasing a processing load of the CPU.SOLUTION: A voltage inputted to a boosted voltage detection section is used for boosted voltage control by dividing a boosted voltage with resistance. A divider circuit of the boosted voltage for independent diagnosis is provided and the voltage dividing ratio thereof is different from that of the voltage division with the resistance. The voltages are inputted to a comparator and compared, thereby detecting abnormality of the voltage dividing ratio. |
