Patent ID: 7253597

Claim:
A curvature corrected bandgap reference circuit, comprising: first and second bipolar transistors having their bases and collectors coupled to first and second circuit common points, respectively; first and second current sources arranged to provide first and second currents I 1 and I 2 , respectively; first and second nodes which receive said first and second currents, respectively, the emitter of said first bipolar transistor coupled to said first node; a differential amplifier connected to said first and second nodes at its inputs, the output of which is arranged to control said first and second current sources such that the voltages at said first and second nodes are equal and said first and second currents are maintained in a fixed ratio; a first resistor connected between said second node and a third node; a second resistor connected between said third node and the emitter of said second bipolar transistor; a third resistor connected between said second node and said first circuit common point; said circuit arranged such that said first and second currents are substantially temperature invariant when the voltages at said first and second nodes are equal such that the signal across said second resistor includes a temperature proportional component and a residual component, wherein said residual component is of the form: (kT/q)ln((T 0 −T x )/(T−T x )), where T 0 is a normalizing measurement temperature and T x is the zero intercept of said temperature proportional component.