Document Type : Original Article

Authors

• Mohtaram Dehban rahimabad
• Ali Heidari

Department of Electrical Engineering, University of Guilan, Rasht, Iran

Abstract

This paper presents a low voltage BJT-based smart temperature sensor with duty cycle modulated output and inaccuracy of ±0.11 ◦C (3σ) and FOM resolution of about 1.4pJ. ◦C2 from −55◦C to 130◦C. This sensor can work with a supply voltage of 1.5V. It uses a BJT-based front-end to generate a proportional to absolute temperature voltage (VPTAT) and a complementary to absolute temperature voltage (VCTAT), which are then modulated to a duty-cycle output. Adding an integrator before the Schmitt trigger has increased the range of input changes of the Schmitt trigger. As a result, the hysteresis of the Schmitt trigger can be increased and it has better noise immunity. Implemented in a standard 0.18-µm CMOS process, the sensor has an active area of about 0.64mm2 and can work with 1.5V from -55◦C to 130◦C with an inaccuracy of ±0.11◦C (3σ). Power consumption is about 45uW.

Keywords

• CMOS temperature sensor
• duty-cycle
• BJT
• Low voltage
• resolution