Patent ID: 7777558

Claim:
A bandgap reference circuit, comprising a negative temperature coefficient current generator, generating a negative temperature coefficient current comprising a constant component, a first negative temperature coefficient component and a second negative temperature coefficient component, wherein the first negative temperature coefficient component is linear to temperature variations and the second negative temperature coefficient component is non-linear to temperature variations; a first positive temperature coefficient current generator, generating a first positive temperature coefficient current that is linear to temperature variations and is for compensating the first negative temperature coefficient component; a second positive temperature coefficient current generator, generating a second positive temperature coefficient current that is non-linear to temperature variations and is for compensating the second negative temperature coefficient component; a coarse tuning circuit, multiplying the negative temperature coefficient current, the first positive temperature coefficient current and the second positive temperature coefficient current by a first number, a second number and a third number, respectively, to generate a first current, a second current and a third current, and summing up the first, second and third currents to generate a coarse-compensated current fitting an ideal curvature; and a transformer, receiving the coarse-compensated current and converting the coarse-compensated current to a bandgap reference voltage or a bandgap reference current.