Voltage comparator circuit and substrate bias adjusting circuit using same

Abstract

Voltage comparator circuit capable of precisely comparing voltages to ground and power supply potentials, without level converter or plurality of power supplies. First and second MOS transistors, with gates commonly connected and drains are connected to a first power supply potential with the same gate width and length. Third MOS transistor with opposite conductive type than first and second, with drain connected to second power supply potential connected to source of first. A fourth MOS transistor with opposite conductive type to the first and second, with a drain connected to the second power supply potential, with same gate width and length as the third. The drain and gate of the first are connected, and a comparative reference potential applies to the gate of the third. Input signal is given to gate of the fourth, and output signal is derived from the drain of the second.