COMPARATOR AND A/D CONVERTER

摘要

A current lowering factor detection unit (2a) detects lowering of a power source voltage (VDD) of a dynamic comparator (1).  Upon detection of lowering of the power source voltage (VDD) by the current lowering factor detection unit (2a), a substrate bias control unit (3a) controls a substrate bias voltage (VBIAS3) of MOS transistors (m0a, m0b) constituting a comparison unit (10) and/or substrate bias voltages (VBIAS1, VBIAS2) of MOS transistors (m2a, m2b, m3a, m3b) constituting a positive feedback unit (20) in the direction that the threshold value voltage of the MOS transistor becomes smaller.