摘要 |
A disconnection detecting apparatus for detecting disconnection of lamps includes a resistor, a differential amplifier, a microcomputer, and a charge pump circuit. The resistor is connected to detect current flowing in the lamps. The voltage that appears at the ends of the resistor is applied to the input terminals of the differential amplifier circuit. The microcomputer detects disconnection of the lamps by comparing the output voltage with a reference. The charge pump circuit increases a battery voltage to a boosted voltage. This boosted voltage is supplied to an operational amplifier in the differential amplifier circuit.
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