A CMOS Thermistor-Embedded Continuous-Time Delta-Sigma Temperature Sensor With a Resolution FoM of 0.65 pJ src='/images/tex/540.gif' alt='^{circ}'> C src='/images/tex/732.gif' alt='^{2}'>

摘要

In a smart temperature sensor system, two individual building blocks, a sensing front-end and an analog-to-digital converter, are cascaded to implement the temperature-to-digital conversion. In this work, a thermistor-embedded continuous-time delta-sigma modulator (CTDSM), which merges these two building blocks into one, is proposed for a hardware- and energy-efficient temperature acquisition. The thermistor-based sensing front-end is reused in a 2nd-order 1 bit CTDSM to attain a high-resolution, low hardware complexity, and energy-efficient temperature sensing. Furthermore, a resistor-ladder with a switch on-resistance compensation scheme is proposed to implement the trimming circuit. Over a range of 45 C 125C, the proposed smart temperature sensor consumes from 1.5 V supply voltage and achieves a resolution around rms (1) temperature resolution with a single conversion time of 100. The corresponding resolution FoM is 0.65 pJ . With 1-point trimming, this design achieves temperature inaccuracy; this inaccuracy can be further improved to - ith additional batch calibration.