| 摘要 |
PROBLEM TO BE SOLVED: To improve the reduction in dynamic range which becomes an issue, when a transistor having a low-threshold voltage is used at a low-power voltage, and widen output voltage range in a current-switching circuit used in a current addition type D/A converter. SOLUTION: A current switch circuit 1 has first and second transistors Tr121 and Tr122, configuring a differential switch 12. A threshold voltage control circuit 5 controls the substrate voltage outputted from its output terminal Vbout to the substrate terminals of the two transistors Tr121 and Tr122, configuring the differential switch 12, and controls the threshold voltage of the two transistors of the differential switch. Thus, even if the power supply voltage of the current-switching circuit 1 is reduced, the output voltage range of the current switch circuit 1 dependent on the thresholds of the two transistors inside the differential switch 12 can be taken large, without causing deterioration in the characteristics. COPYRIGHT: (C)2011,JPO&INPIT
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