A BANDGAP VOLTAGE REFERENCE CIRCUIT AND A METHOD FOR PRODUCING A TEMPERATURE CURVATURE CORRECTED VOLTAGE REFERENCE

摘要

A bandgap voltage reference circuit (1) comprises a bandgap cell (7) comprising first and second transistor stacks (8, 9) of first transistors (Q1, Q2) and second transistors (Q3, Q4), respectively, arranged for developing a correcting PTAT voltage (AVbe) across a primary resistor (Rl) proportional to the difference in the base-emitter voltages of the first and second transistor stacks (8,9). A first current mirror circuit (10) provides PTAT currents (12 to 15) to the emitters of the first and second transistors (Q1 to Q4), and an operational amplifier (A1) maintains the voltage on the emitter of the first transistor (Q2) of the first transistor stack (8) at the same level as the resistor (R1) and sinks a PTAT current from the first current mirror circuit (10) from which the other PTAT currents are mirrored. The correcting PTAT voltage (dVbe) developed across the primary resistor (R1) is scaled onto a secondary resistor (R3) and summed with the uncorrected base-emitter CTAT voltage of the first transistor (Ql) of the first transistor stack (8) for providing the voltage reference between an output terminal (5) and ground (3). A CTAT correcting current (I,,) is summed with the PTAT current (13) and applied to the emitter of the second transistor (Q3) of the second transistor stack (9) so that the correcting PTAT voltage (dVbe) developed across the primary resistor (R1) has a T1nT curvature complementary to the TinT temperature curvature of the uncorrected base-emitter CTAT voltage of the first transistor (Ql). Thus the reference voltage developed between the output terminal (5) and the ground (3) is temperature stable and T1nT temperature curvature corrected. The CTAT correcting current is derived from the base-emitter CTAT voltage of the first transistor (Q 1) in a CTAT current generating circuit (12) through a second current mirror circuit (15).