EFFECT OF OPERATING-CONDITIONS ON THE DYNAMIC-RESPONSE OF THERMAL SENSORS WITH AND WITHOUT ANALOG FEEDBACK

The effect of the operating conditions of a thermal sensor on its dyna mic response is considered with regard to operation both with and with out analog feedback, the latter being the classic solution to improve dynamic response. The effect of aspects such as overheat level, heat-t ransfer rate and feedback linearity are discussed. The thermal behavio ur of the system is modelled as a first-order system with a constant t ime delay in the feedback loop. To provide fundamental insight into th e dependencies, a general analysis is first carried out in the thermal domain, to reveal aspects that are independent of any specific electr onic implementation. This is followed by investigation of the most com monly employed implementation, that of a self-heating resistive elemen t in a bridge configuration.