Patent ID: 6774711
Filing Date: 2004-08-10
Classification: G05F

Abstract:
A bandgap voltage reference circuit comprising:a proportional-to-absolute-temperature (PTAT) module for generating a first PTAT current and a second PTAT current; a first amplifier stage comprising a first NMOS transistor having a drain that is coupled to said PTAT module through a first current mirror for receiving said first PTAT current, a gate of said first NMOS transistor coupled to a gate of a second NMOS transistor, said second NMOS transistor having a drain that is coupled to said PTAT module through a second current mirror for receiving said second PTAT current, said drain of said second NMOS transistor also couples to its gate, a source of each of said first NMOS transistor and said second NMOS transistor couples to a ground; a second amplifier stage coupled to said first amplifier stage and said PTAT module for receiving an amplified signal from said first amplifier stage and transferring said amplified signal back to said PTAT module; and an output circuit coupled to said PTAT module for receiving said first PTAT current and for generating a reference voltage that does not change with temperature.