An energy-efficient BJT-based Temperature-digital converter based on a Continuous-Time Readout

An energy-efficient BJT-based Temperature-digital converter based on a Continuous-Time Readout

Kishore Kumar, Rushil (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Electronic Instrumentation)

Makinwa, K.A.A. (mentor)

Delft University of Technology

Electrical Engineering

2018-10-24

This thesis presents the most energy-efficient BJT-based CMOS temperature-to-digital converter (TDC) reported to date. It is based on a continuous-time front-end, which avoids the kT/C noise limit incurred by previous discrete-time (switched-capacitor) front-ends. An energy-efficient capacitively-coupled instrumentation amplifier (CCIA) boosts ΔVbe, a small temperature-dependent voltage (~150uV/°C) derived from two BJTs, before it is digitized by an ADC. Like conventional switched-capacitor front-ends, the CCIA’s gain is determined by capacitor ratios, resulting in similar levels of accuracy. Fabricated in a 0.18um CMOS process, the TDC achieves an inaccuracy of ±0.12°C (3σ) from -40°C to +125°C after a room-temperature calibration. This is comparable with the state-of-the-art. Furthermore, it achieves 1.27mK resolution in a 320 millisecond conversion time, while consuming 8.9uW. This corresponds to a state-of-the-art resolution FoM of 4.5pJ∙K2.

BJT-based TDC
Energy-efficient
Precision Temperature Sensor

http://resolver.tudelft.nl/uuid:83b1b70f-7ff5-4693-a029-69a4ee9e4e41

2021-10-24

Student theses

master thesis

© 2018 Rushil Kishore Kumar