CURVATURE-CORRECTED BANDGAP REFERENCE

摘要

A curvature-corrected bandgap reference comprising a first BJT device operating at a first current density that is substantially proportional to absolute temperature, the first BJT device having a first base-emitter voltage and a first base terminal and a second BJT device operating at a second current density that is substantially independent of temperature, the second BJT device having a second base-emitter voltage and a second base terminal. The first and second base terminals operate at a reference voltage. The reference voltage comprises a linear combination of the first and second base-emitter voltages and is thereby made substantially independent of temperature and curvature-corrected. The linear combination is provided by summing the first base-emitter voltage, a proportional to absolute temperature (PTAT) voltage proportional to a first current density, and a curvature-correction voltage proportional to a difference between the first and second base-emitter voltages.

主权项

1. A curvature-corrected bandgap reference, comprising:
a first current source proportional to absolute temperature; a first resistor which conducts the first current to generate a proportional to absolute temperature voltage; the curvature-corrected bandgap reference 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 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 circuit operable to force the second current density to be substantially proportional to the reference voltage; wherein the circuit further includes a resistor coupled to the reference voltage; and 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 first and second BJT devices which diverts current nominally equal to that contributed by base currents of the first and second BJT devices such that the first and second current densities are nominally independent of the base currents of the first and second BJT devices, wherein accuracy of curvature correction is thereby improved.