| 摘要 |
A digital-analog converter includes a counter ( 13 ) for performing counting operation according to clocks (CK 1 , CK 2 ), a comparator ( 12 ) for comparing the count value to a digital input value and outputting the clocks (CK 1 , CK 2 ) until the values coincide, switches (SW 1 , SW 2 ) which turn ON/OFF according to the clocks (CK 1 , CK 2 ), and a capacitor (C 1 ) which charges and discharges by utilizing constant current sources ( 21, 22 ) when the switches (SW 1 , SW 2 ) are ON. A digital portion ( 10 ) including the comparator ( 12 ) and the counter ( 13 ) is completely separated from an analog portion ( 20 ) including the capacitor (C 1 ) and the switches (SW 1 , SW 2 ) and these portions are connected only by the clocks (CK 1 , CK 2 ), so that the digital portion ( 10 ) and the analog portion ( 20 ) can be designed separately.
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