BJT Based Translinear Implementation of an Evolutionary Optimised Non-Linear Function for Sensor Linearisation

The linear characteristics of temperature sensors are affected by material properties, aging, self-heating, lead resistance, and external interference. This study aims to improve sensor characteristics by overcoming power consumption and response time limitations. An evolutionary optimised log-ratiometric function is implemented for sensor linearisation using a translinear circuit. The differential evolution optimisation strategy is used to find the optimum values of the linearising parameters in the non-linear function. Further, these parameters are applied to the current mode circuit to linearise the selected sensors as an input current source. Due to higher fidelity, better comprehensive dynamic range, and improved linear areas, implementing the non-linear function using the BJT-based current mode circuit results in a better full-scale error reduction capability than MOSFET-based translinear implementation. Furthermore, the devices such as Gallium Arsenide Field-Effect Transistors (GaAsFET) and Modulation-Doped FET (MODFET) could be used in place of BJT in the future for additional error reduction due to rapid response speed, low power consumption, and reduced internal noise. Thus, the translinear implementation of the non-linear function can enhance the sensor characteristics in all aspects.