| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact and simple A/D converter. SOLUTION: An output voltage of a CR charging circuit 17 is compared with a prescribed reference voltage, a detection voltage of a line voltage and a detection voltage of a line current respectively at comparators 20, 21, 22 and its output is given to a microcomputer C 29, where each pulse width is measured by using its internal counter, the pulse width of the latter two voltages is respectively divided by a pulse width of the former voltage so as to conduct a prescribed calibration, thereby conducting, an A/D conversion. The D/A conversion is conducted by giving an output digital signal from the microcomputer to a linear low-pass filter. |
