| 摘要 |
<p>PURPOSE:To digitize the analog input signals up to the power supply voltage with high accuracy and without increasing so much the pellet area, by using the 1st and 2nd D/A converters, a capacity element and a differential amplifier. CONSTITUTION:The analog input signal Vx is sampled to a capacity 14 (Vx- VREF/2) by switches 11 and 13. The output 19 delivered from the 1st resistance train of a D/A converter 18 is controlled by a successive comparison register 17 for comparison of upper bits. The output 20 of the 2nd resistance train 67 of the converter 18 is applied to a differential amplifier 16 in the form of VREF/2 during comparison of upper bits. While the output 20 is controlled by the register 17 during comparison of lower bits. Thus it is possible to perform an A/D conversion of signals with high accuracy and without increasing so much the pellet area despite the increase of the number of conversion bits.</p> |
