A REFERENCE CIRCUIT HAVING A CONTROLLED TEMPERATURE DEPENDENCE

摘要

Mobility in a FET is used as a time standard to develop a resistance (or a transconductance or a current) reference which may be fully integrated and which is temperature stable to an arbitrary desired accuracy (or which varies with temperature in a desired fashion). The large temperature dependence of mobility is compensated (or adjusted to a desired variation characteristic) by applying a gate bias voltage having a predetermined variation in value with respect to temperature. In one embodiment the bias voltage of the FET is given a temperature dependence which results in the drain current of the FET being substantially constant with respect to temperature. This current is then used to charge or discharge a capacitor, yielding a precise R-C product which may be implemented fully in integrated form.