Temperature sensing circuits in CMOS-SOI technology

This paper compares various circuits allowing on-line temperature measurement and monitoring implemented in CMOS-SOI technology. Firstly, we discuss two architectures implementing an integrated circuit that generates an accurate output current or voltage proportional to the absolute temperature, i.e. PTAT. Secondly, we propose another type of integrated circuit that uses the MOSFET threshold voltage to determine the chip local temperature, namely Vt extractor circuit. The accuracy, linearity, sensitivity and calibration problems of the different circuits are discussed and compared with each other in the temperature range of 300K-420K. It is shown that threshold voltage extractor circuits are very appropriate to determine the temperature of low power, analog and mixed-signal designs due to their accuracy, low power consumption and no need for calibration. The circuits have been fabricated using 1μm partially depleted (PD) CMOS-SOI technology, and their accuracy has been experimentally verified by comparing simulated and measured results.