Patent ID: 7633334
Filing Date: 2009-12-15
Classification: G05F

Abstract:
1. A method for generating a bandgap reference voltage from an input power supply voltage having a wide voltage range, said method comprising: generating a regulated power supply voltage from the input power supply voltage; maintaining the regulated power supply voltage at a substantially constant voltage level relative to the input power supply voltage; generating a proportional to absolute temperature (“PTAT”) current in a first resistor using PTAT current generation circuitry comprising a first diode-connected transistor having a first voltage drop and a second diode-connected transistor having a second voltage drop, wherein the PTAT current is proportional to a difference between the first and second voltage drops, and wherein the first and second diode-connected transistors are powered by the regulated power supply voltage; generating a clamping voltage from the input power supply voltage that is greater than the regulated power supply voltage and less than the input power supply voltage; maintaining the clamping voltage at a substantially constant voltage level relative to the input power supply voltage; and generating the bandgap reference voltage using bandgap reference voltage generation circuitry comprising a third diode-connected transistor and a second resistor that are powered by the clamping voltage, wherein the bandgap reference voltage is generated using the PTAT current to produce a voltage across the second resistor proportional to a ratio between the first resistor and the second resistor.