Accurate temperature measurement method for low beta transistors

摘要

An accurate temperature monitoring system that uses a precision current control circuit to apply accurately ratioed currents to a semiconductor device, which may be a bipolar junction transistor (BJT), used for sensing temperature. A change in base-emitter voltage (DeltaV_BE) proportional to the temperature of the BJT may be captured and provided to an ADC, which may generate a numeric value corresponding to that temperature. The precision current control circuit may be configured to generate a reference current, capture the base current of the BJT, generate a combined current equivalent to a sum total of the base current and a multiple of the reference current, and provide the combined current to the emitter of the BJT. In response to this combined current, the collector current of the BJT will be equivalent to the multiple of the reference current. The ratios of the various collector currents conducted by the BJT may thus be accurately controlled, leading to more accurate temperature measurements.