A 0.97 nJ/Conversion BJT-Based Temperature Sensor With a Low-Power Two-Stage Dynamic Comparator
Alireza Mosalmani, Yasser Rezaeiyan, Simon Richter, Milad Zamani, Yarallah Koolivand, Farshad Moradi · IEEE Transactions on Very Large Scale Integration (VLSI) Systems · 2025
This article presents a low-power fully CMOS temperature sensor in a 65 nm process, suitable for monitoring the battery-powered application-specific integrated circuit (ASIC) designs. The circuit converts a proportional-to-absolute-temperature (PTAT) current to a complementary-to-absolute-temperature (CTAT) binary code using a low-power time-to-digital converter to-digital converter (TDC). To enhance conversion efficiency, we introduce a two-stage dynamic comparator that consumes 40% less power than conventional designs by enabling the preamplifier only when precise detection of the integration stop time is required. The 0.16$\text{mm}^{2}$prototype consumes only 0.97 nJ/conversion, achieving a resolution figure of merit (FoM) of 0.018 nJ$\cdot $$\text{K}^{2}$. Measurements show an inaccuracy of$\pm 0.85~^{\circ }$C ($3\sigma $) over a temperature range of –$20~^{\circ }$C to$+ 120~^{\circ }$C.