Abstract: The battery monitoring IC is provided with the short circuiting switch that includes the switching element that shorts the input side and the output side of the boosting circuit that boosts the power supply voltage to the driving voltage, that can drive the MOS transistor within the buffer amplifier in the saturated region, and supplies the driving voltage as the driving voltage of the buffer amplifier. An abnormality of the boosting circuit can be diagnosed by comparing the output voltage, that is measured when the short circuiting switch is turned off and the driving voltage boosted by the boosting circuit is supplied to the buffer amplifier, and the output voltage, that is measured when the short circuiting switch is turned on and the power supply voltage is, without going through the boosting circuit, supplied as is to the buffer amplifier.

Abstract: The battery monitoring IC is provided with the short circuiting switch that includes the switching element that shorts the input side and the output side of the boosting circuit that boosts the power supply voltage to the driving voltage, that can drive the MOS transistor within the buffer amplifier in the saturated region, and supplies the driving voltage as the driving voltage of the buffer amplifier. An abnormality of the boosting circuit can be diagnosed by comparing the output voltage, that is measured when the short circuiting switch is turned off and the driving voltage boosted by the boosting circuit is supplied to the buffer amplifier, and the output voltage, that is measured when the short circuiting switch is turned on and the power supply voltage is, without going through the boosting circuit, supplied as is to the buffer amplifier.

Abstract: In a scanning mode: a conversion sequence setting register sets the sequence in which analogue signals are to be converted; a multiplexer selects a single analogue signal sequentially from a plurality of analogue signals, in accordance with the order that is set in this conversion sequence setting register; an A/D converter converts the analogue signal selected by this multiplexer to a digital signal; a conversion result register having a plurality of result registers stores the digital signal obtained by conversion by the A/D converter in these storage regions in the order in which conversion was effected; and a back-up register includes result registers respectively corresponding to this plurality of result registers.