Effect of operating conditions on the dynamic response of thermal sensors with and without analog feedback

Abstract The effect of the operating conditions of a thermal sensor on its dynamic response is considered with regard to operation both with and without analog feedback, the latter being the classic solution to improve dynamic response. The effect of aspects such as overheat level, heat-transfer rate and feedback linearity are discussed. The thermal behaviour of the system is modelled as a first-order system with a constant time delay in the feedback loop. To provide fundamental insight into the dependencies, a general analysis is first carried out in the thermal domain, to reveal aspects that are independent of any specific electronic implementation. This is followed by investigation of the most commonly employed implementation, that of a self-heating resistive element in a bridge configuration.