| 摘要 |
PURPOSE:To attain characteristics with high resolution and accuracy, by inputting a control data to a pulse modulator as a feedback data, D/A-converting the data and feeding back it to a comparator. CONSTITUTION:A comparator 101 compares an input signal with a feedback signal of a D/A converter 109 and outputs a signal of result of comparison in binary value. A counter 103 outputs the output as the content of count at the end of count at each repetitive period of a modulation wave of a pulse width modulator 107. Based on a data including at least the most significant digit of the content of count, a control logical circuit 105 outputs a control data of an approximate value depending on the level of the input analog signal. The data is outputted through A/D conversion by a register 104 and fed back to a modulator 107. A register 106 stores the content of count and outputs the data as another A/D conversion data representing a fraction of a digital value corresponding to the input analog signal. |
