Patent ID: 8008966
Filing Date: 2011-08-30
Classification: G05F

Abstract:
1. A start-up circuit which is used in a bandgap reference voltage generating circuit, the start-up circuit comprising: a first PMOS transistor having a drain connected to a power supply terminal, and a source and a gate connected with each other; a first NMOS transistor having a drain connected to the source of the first PMOS transistor and a gate connected to a bandgap output terminal; a second NMOS transistor having a drain connected to a source of the first NMOS transistor, a source connected to a ground terminal, and a gate to which a first mode signal is applied; a third NMOS transistor having a drain connected to an output terminal of an operational amplifier and a gate connected to the drain of the first NMOS transistor; and a fourth NMOS transistor having a source connected to the ground terminal, a drain connected to a source of the third NMOS transistor, and a gate to which the first mode signal is applied.