Patent ID: 9098098
Filing Date: 2015-08-04
Classification: G05F

Abstract:
1. A curvature-corrected bandgap reference, comprising: a Brokaw bandgap circuit; the Brokaw bandgap circuit including an output node providing a reference voltage; the Brokaw bandgap circuit further comprising a first BJT device including a first base terminal coupled to the output node and a first emitter terminal, wherein the first BJT device operates at a first current density that is substantially proportional to absolute temperature; a second BJT device including a second base terminal coupled to the output node and a second emitter terminal, wherein the second BJT device operates at a second current density that is substantially independent of temperature; a correction voltage proportional to a voltage difference of the first and second emitter terminals, wherein the correction voltage substantially cancels a curvature of the reference voltage; and a first circuit operable to force the second current density to be substantially proportional to the reference voltage; wherein the Brokaw bandgap circuit further comprises a third BJT device operating at a third current density that is substantially proportional to absolute temperature, the third current density being less than the first current density by a fixed ratio; wherein the first circuit further includes a resistor coupled to the reference voltage; a current mirror coupled to the resistor and to a collector of the second BJT device; and a base current compensation block coupled to the collector of the second BJT device which diverts a current nominally equal to that contributed by base currents of the first second and third BJT devices such that the second current density is nominally independent of the base currents of the first, second and third BJT devices, wherein accuracy of curvature correction is thereby improved.