<p>One A/D converter (1) and the other A/D converter (2) have a common power supply voltage and sample an A/D conversion value at short time intervals and at a long time intervals, respectively. Both the A/D converter (1) and the A/D converter (2) are set in a constant active state (continuous conversion mode). This allows the total consumption current (Ia) combining the consumption current (Ia1) of the A/D converter (1) and the consumption current (Ia2) of the A/D converter (2) to be constant, so that the power supply voltage (Vcc) is stabilized and a stable A/D conversion value can be obtained from each of the A/D converters.</p>
