Patent ID: 6489836
Filing Date: 2002-12-03
Classification: G05F

Abstract:
A reference voltage source circuit, comprising:a reference voltage generation circuit that produces a first reference voltage with a first temperature characteristic; and a level shifter circuit coupled to the reference voltage generation circuit and that produces a second reference voltage from the first reference voltage such that the second reference voltage has a temperature characteristic which has the same sign as the first temperature characteristic, wherein the reference voltage generation circuit comprises: a first resistor having a first terminal connected to a power supply node and a second terminal connected to a first node at which the first reference voltage is produced; a second resistor having a first terminal coupled to the first node; a first NMOS transistor having a source terminal connected to a second terminal of the second resistor at a second node and a gate terminal connected to the first node; a second NMOS transistor having a source terminal connected to a drain terminal of the first NMOS transistor at a third node, a gate terminal connected to the power supply node, and a drain terminal connected to a power supply ground; and a PMOS transistor having a source terminal connected to the first node, a gate terminal connected to the second node and a drain terminal connected to the power supply ground.