| 摘要 |
PROBLEM TO BE SOLVED: To reduce circuit scale and power consumption by providing interrupt switches between the gates of pair of MOS transistor in a sample-and-hold circuit, grounding one gate through a capacitor and inputting an analog signal current. SOLUTION: An analog voltage signal is converted into a current signal and is inputted to plural sample-and-holding circuits. A sample switch SW 2 can interrupt the gates of a pair of MOS transistors T12 and T22 in sample- and-hold circuit SH1 and the gates of SW2 and T22 are connected to low voltage through sample capacitor C2. The charge of the MOS transistor T22 is maintained by a charge held by sample capacitor C2 after interrupt, and the analog current signal which is sample-held is inputted to a multiplexer, in accordance with a spread code while a part of input current is interrupted. Thus, the analog current signal can be held, and the conversion of a digital signal can be dispensed with. |
