| 摘要 |
PURPOSE:To bring A/D conversion to effect with high precision by providing a voltage source which generates a voltage equal to the logical output voltage of each comparator and then by setting the output voltage of a reference voltage source by the output of this voltage source. CONSTITUTION:Comparators 22 and 23 are provided and logical voltage VH-VL (VH and VL represent high and low levels corresponding to logical values ''1'' and ''0'') generated by using both comparators is voltage-divided by resistances 12 and 13. Because of the above-mentioned constitution, potential difference Vin-VL between VL and analog potential Vin is A/D-converted by regarding potential difference Vd=VH-VL as a reference potential difference; the converted voltage ranges VL-VL+Vd, i.e., VL-VH and the smallest potential difference where the lowest- order bit changes is approximately 1/8Vd. As a result, there is no difference between the reference voltage and logical output voltage, giving effect to high- precision A/D conversion. |
