Patent ID: 6166588
Filing Date: 2000-12-26
Classification: G05F

Abstract:
A power supply circuit, comprising:a reference voltage generating circuit; andan internal voltage generating circuit,wherein said reference voltage generating circuit comprises a resistor, of which one end is coupled to a power supply terminal and a first N-type field effect transistor, of which a drain electrode is coupled to the other end of said resistor, a source electrode is coupled to an earth terminal, and a gate electrode is coupled to said drain electrode;wherein said internal voltage generating circuit comprises a second N-type field effect transistor, of which a gate electrode is coupled to the drain electrode of said first N-type field effect transistor and a source electrode is coupled to said earth terminal, and a constant voltage generating circuit for outputting a constant voltage, coupled between the drain electrode of said second N-type field effect transistor and said power supply terminal; andwherein further the length of said gate electrode of said first N-type field effect transistor is longer than the length of said gate electrode of said second N-type field effect transistor.