| 摘要 |
PURPOSE:To prevent converted data from an A/D converter from varying with a supply voltage, by using a power voltage supplied through a protecting circuit to a sensor as the reference voltage of the A/D converter. CONSTITUTION:A power voltage supplied to sensors 6-8 through overcurrent protecting circuits 3-5 is used as the reference voltage of an A/D converter 16. Consequently, converted data from said converter 16 is prevented from varying with the supply voltage to the sensors 6-8, and the converted data is accurate even when the stability of a constant-voltage circuit 2 as a supply voltage source is not so high. In addition, even if the supply voltage to the sensors 6-8 varies owing to the short circuit, etc., of some of supply lines to the sensors 6-8, any influence upon the power voltage supplied to the whole of a digital control circuit 18 is not exerted, securing the normal operation of the digital control circuit 18 at any time. |
