Patent ID: 7411380

Claim:
A bandgap reference circuit, comprising: a PTAT current unit, generating a PTAT current and summing a non-linear current; a first transistor, biased by the PTAT current output from the PTAT current unit; a second transistor, biased by the PTAT current output from the PTAT current unit; an amplifier and voltage divider circuit, for outputting a reference voltage in response to a base-emitter voltage, a PTAT voltage, and a non-linear voltage; and a non-linearity compensation circuit, for converting the reference voltage as a temperature independent bias current, wherein the non-linearity compensation circuit comprises: a third transistor, biased by the temperature independent current; a first resistor, coupled to the first transistor and the third transistor, wherein the voltage drop across the first resistor is the non-linear voltage; and a second resistor, coupled to the third transistor, wherein the voltage drop across the second resistor is the non-linear voltage; wherein the non-linear effect and the temperature dependent effect of the reference voltage are compensated by the non-linearity compensation circuit.