Leakage current compensation for a 450 nW, high-temperature, bandgap temperature sensor

The design of a 450nW bandgap temperature sensor in the 0 to 175°C range is presented. The design demonstrates a leakage current compensation technique that is useful for low-power designs where transistor performance is limited. The technique mitigates the effects of leakage in Brokaw bandgap references by limiting the amount of excess current that is entering the bases of the main bipolar pair due to leakage. Using this technique, Monte Carlo simulations show an improvement factor of 7.6 for the variation of the temperature sensitivity over the full temperature range. For the variation of the reference voltage, Monte Carlo simulations show an improvement factor of 2.3. Sensors built using this technique can be used to accurately monitor the temperature of power semiconductors since wireless temperature sensors become feasible with sufficiently low power consumption.