SUCCESSIVE APPROXIMATION TYPE A/D CONVERTER, MOBILE BODY WIRELESS DEVICE

摘要

Sampling switches (SWp and SWn), during a sampling period, cause analog signals (Vinp and Vinn) to be sampled by sampling nodes (Nsp and Nsn). A control unit (103), during the sampling period, controls supply switch units (100p and 100n) so that a grounding voltage (Vss) is supplied to up capacities (15up to 11up, and 15un to 11un) and a power supply voltage (Vdd) is supplied to down capacities (15dp to 11dp, and 15dn to 11dn). Furthermore, the control unit (103) controls the supply switch units (100p and 100n) according to a comparison result of a comparator (102) in each of the bit determination periods corresponding to the respective bit values (D5 to D1) excluding the lowest-order bit value (D0) so that analog voltages (Vp and Vn) asymptotically approach each other.