Patent ID: 7408335

Claim:
A band-gap reference circuit having a plurality of operating states which respectively correspond to a plurality of values of a band-gap reference voltage, comprising: a current source; a circuit branch coupled to said current source for receiving current generated by said current source, said circuit branch including a resistor having a positive temperature coefficient connected in series with a base-emitter diode having a negative temperature coefficient, wherein said current develops a combined voltage across said series connection of said resistor and said base-emitter diode; a further base-emitter diode; an adjustment circuit having an output coupled to said current source and having inputs respectively coupled to said circuit branch and said further base-emitter diode for adjusting the band-gap reference voltage based on said combined voltage and a base-emitter voltage of said further base-emitter diode; and a start circuit having a first output connected to at least one of said inputs of said adjustment circuit for preventing operation in one of said operating states and a second output connected to said output of said adjustment circuit for applying a bias voltage to said output of said adjustment circuit.