Title
An energy-efficient BJT-based temperature sensor with a continuous-time readout
Author
Toth, Nandor (TU Delft Electrical Engineering, Mathematics and Computer Science)
Contributor
Makinwa, K.A.A. (mentor) 
Pan, S. (graduation committee)
Degree granting institution
Delft University of Technology
Programme
Electrical Engineering
Date
2021-10-20
Abstract
This thesis presents an energy-efficient high-accuracy temperature sensor that combines a BJT front-end with a continuous-time readout circuit. Its front-end is based on PNP transistors, which, compared to NPNs, are more widely available in CMOS processes and less sensitive to stress. In this design, proportional-to-absolute-temperature (PTAT) and complementary-toabsolute-temperature (CTAT) currents are created by forcing ΔVBE and VBE over two resistors
of the same type, after which their ratio is digitized by a continuous-time Delta-Sigma Modulator (CTDSM). As a result, the sampling noise present in traditional switched-capacitor (SC) modulators is eliminated, which improves the sensor’s energy efficiency. High accuracy is achieved by the liberal use of chopping and dynamic element matching techniques. Fabricated in a 0.18µm CMOS process, the sensor achieves a 0.15°C (3σ) inaccuracy over the industrial temperature range (-45°C to 85°C) after a 1-point temperature calibration. It also achieves a 1.24mK resolution in 56.3ms, while consuming only 16µW. This corresponds to a state-of-theart resolution Figure-of-Merit (FoM) of 1.4pJ°C2.
Subject
BJT-based TDC
Temperature Sensor
Continuous-Time
To reference this document use:
http://resolver.tudelft.nl/uuid:a8792645-c44b-4e67-8aba-a9e4b52c0951
Embargo date
2025-10-20
Part of collection
Student theses
Document type
master thesis
Rights
© 2021 Nandor Toth