Patent ID: 6894473
Filing Date: 2005-05-17
Classification: G05F

Abstract:
1. A bandgap reference circuit, comprising: a current generation circuit having a supply level start-up transistor, the current generation circuit operable to generate a reference current having a positive function of a temperature; a voltage generation circuit connected to the current generation circuit, the voltage generation circuit operable to receive the reference current from the current generation circuit and produce a reference voltage in response to the reference current; and a smart clamping circuit connected to the voltage generation circuit, wherein the smart clamping circuit clamps the reference voltage to quickly bring the reference voltage output of the voltage generation circuit to its final value, thereby producing a fast and stable reference voltage signal; and a discharge circuit connected to the current generation circuit and the voltage generation circuit, the discharge circuit operable to initially discharge a residual potential in the current generation circuit and in the voltage generation circuit, the discharge circuit comprising: a first MOS transistor having a first terminal connected to the current generation circuit, a second terminal connected to circuit ground, and a control terminal connected to an enable bar input terminal; a second MOS transistor having a first terminal connected to the voltage generation circuit, a second terminal connected to circuit ground, and a control terminal connected to the enable bar input terminal and the control terminal of the first MOS transistor; and wherein the first and second MOS transistors are operable to conduct based on a signal at the control terminals to initially discharge a residual potential in the current generation circuit and in the voltage generation circuit, thereby enhancing repeatability and settling time of the output of the bandgap voltage reference circuit.