Circuit and method for beta variation compensation in single-transistor temperature sensor

摘要

A circuit (1-2) for compensating for variations in the current gain &bgr; of a sensing transistor (Q1) having a collector coupled to a reference voltage (GND) includes a first current mirror (20) having an input coupled to a base of the sensing transistor. A second current mirror (21) has an input coupled to an output of the first current mirror. A current source (13) is coupled to provide emitter current for the sensing transistor. An output of the second current mirror circuit (21) feeds base current of the sensing transistor back to its emitter to cause the collector current of the sensing transistor to be precisely equal to the current (I1) provided by the current source.