Patent ID: 6724176
Filing Date: 2004-04-20
Classification: G05F

Abstract:
A band-gap reference circuit comprising:a first current source for generating a first reference current; a first circuit branch for receiving a portion of said first reference current, said first circuit branch comprising a first resistor having a positive temperature coefficient connected in series with a base-emitter junction of a first PNP diode having a negative temperature coefficient, wherein an emitter current of said first PNP diode develops a first combined voltage across said series connection of said first resistor and said base-emitter junction of said first PNP diode; a comparison circuit for comparing said first combined voltage to a base-emitter voltage of a second PNP diode and, in response to said comparison, adjusting a band-gap reference voltage; and a correction current generating circuit capable of injecting a correction current into an emitter of said second PNP diode, wherein said injected correction current at least partially offsets a non-linear drop-off in said band-gap reference voltage caused by said second PNP diode as temperature increases.