A 1.2V Self-Referenced Temperature Sensor With a Time-Domain Readout and a Two-Step Improvement on Output Dynamic Range

A self-referenced temperature sensor with a time-domain readout and a two-step improvement on output dynamic range is presented in this paper. The proposed temperature sensor utilizes BJTs to generate temperature dependent/independent currents, which are converted to digital bits using a ring-oscillator-based time-domain readout scheme. A novel two-step improvement on output dynamic range is proposed to improve the power-efficiency and simplify the hardware design with a high conversion rate. Furthermore, the adopted process compensation strategy and the self-referenced readout scheme make the whole temperature sensor robust to process and supply variations. Fabricated in a standard 0.13-<inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> CMOS process, the proposed temperature sensor occupies a die area of 0.06 mm<sup>2</sup> and consumes 9.92 nJ per conversion at a conversion rate of 75 kSa/s. After one-point calibration at 20 °C, the sensor achieves inaccuracies of −2.88 °C/+2.71 °C and −1.7 °C/1.36 °C from −20 °C to 100 °C, with and without systematic nonlinearity removal, respectively. It shows an average supply sensitivity of 0.0136 °C/mV from 1.05 V to 1.4 V without any external reference clock or voltage regulators.

[1]  J. Huijsing,et al.  A CMOS smart temperature sensor with a 3σ inaccuracy of ±0.1°C from -55°C to 125°C , 2005, IEEE J. Solid State Circuits.

[2]  A. Bakker,et al.  High-Accuracy CMOS Smart Temperature Sensors , 2000 .

[3]  Chin-Chung Tsai,et al.  A time-to-digital-converter-based CMOS smart temperature sensor , 2005, 2005 IEEE International Symposium on Circuits and Systems.

[4]  Kofi A. A. Makinwa,et al.  A CMOS temperature sensor with a voltage-calibrated inaccuracy of ±0.15°C (3σ) from −55 to 125°C , 2012, 2012 IEEE International Solid-State Circuits Conference.

[5]  Amine Bermak,et al.  A Passive RFID Tag Embedded Temperature Sensor With Improved Process Spreads Immunity for a -30°C to 60°C Sensing Range. , 2014 .

[6]  J. Burm,et al.  An Ultralow Power Time-Domain Temperature Sensor With Time-Domain Delta–Sigma TDC , 2017, IEEE Transactions on Circuits and Systems II: Express Briefs.

[7]  Santiago Celma,et al.  Low-voltage low-power CMOS rail-to-rail V-I converters , 2011, 2011 20th European Conference on Circuit Theory and Design (ECCTD).

[8]  Wei Hu,et al.  A CMOS Smart Temperature Sensor With Single-Point Calibration Method for Clinical Use , 2016, IEEE Transactions on Circuits and Systems II: Express Briefs.

[9]  Trong-Hieu Tran,et al.  A Low-ppm Digitally Controlled Crystal Oscillator Compensated by a New 0.19-mm2 Time-Domain Temperature Sensor , 2017, IEEE Sensors Journal.

[10]  Kyoungho Woo,et al.  Dual-DLL-based CMOS all-digital temperature sensor for microprocessor thermal monitoring , 2009, 2009 IEEE International Solid-State Circuits Conference - Digest of Technical Papers.

[11]  Kofi A. A. Makinwa,et al.  A CMOS temperature sensor with a 49fJK2 resolution FoM , 2017, 2017 Symposium on VLSI Circuits.

[12]  Kofi A. A. Makinwa,et al.  11.4 1650µm2 thermal-diffusivity sensors with inaccuracies down to ±0.75°C in 40nm CMOS , 2016, 2016 IEEE International Solid-State Circuits Conference (ISSCC).

[13]  Kofi A. A. Makinwa,et al.  A CMOS smart temperature sensor with a 3σ inaccuracy of ±0.1°C from -55°C to 125°C , 2005, IEEE J. Solid State Circuits.

[14]  Kyoungho Woo,et al.  Time-Domain CMOS Temperature Sensors With Dual Delay-Locked Loops for Microprocessor Thermal Monitoring , 2012, IEEE Transactions on Very Large Scale Integration (VLSI) Systems.

[16]  David Blaauw,et al.  9.2 A 0.6nJ −0.22/+0.19°C inaccuracy temperature sensor using exponential subthreshold oscillation dependence , 2017, 2017 IEEE International Solid-State Circuits Conference (ISSCC).

[18]  Johan H. Huijsing,et al.  Micropower CMOS temperature sensor with digital output , 1996, IEEE J. Solid State Circuits.

[19]  Kofi A. A. Makinwa,et al.  A BJT-based temperature-to-digital converter with ±60mK (3σ) inaccuracy from −70°C to 125°C in 160nm CMOS , 2016, 2016 IEEE Symposium on VLSI Circuits (VLSI-Circuits).

[20]  Poki Chen,et al.  A 486k S/s CMOS time-domain smart temperature sensor with −0.85°C/0.78°C voltage-calibrated error , 2015, 2015 IEEE International Symposium on Circuits and Systems (ISCAS).

[21]  Kofi A. A. Makinwa,et al.  9.3 A BJT-based temperature sensor with a packaging-robust inaccuracy of ±0.3°C (3σ) from −55°C to +125°C after heater-assisted voltage calibration , 2017, 2017 IEEE International Solid-State Circuits Conference (ISSCC).

[22]  Kofi A. A. Makinwa,et al.  A VCO Based Highly Digital Temperature Sensor With 0.034 °C/mV Supply Sensitivity , 2016, IEEE Journal of Solid-State Circuits.

[23]  Joseph Shor,et al.  Miniaturized BJT-Based Thermal Sensor for Microprocessors in 32- and 22-nm Technologies , 2013, IEEE Journal of Solid-State Circuits.

[24]  David Blaauw,et al.  A Fully-Integrated 71 nW CMOS Temperature Sensor for Low Power Wireless Sensor Nodes , 2014, IEEE Journal of Solid-State Circuits.

[25]  Kofi A. A. Makinwa,et al.  A 2800-μm2 thermal-diffusivity temperature sensor with VCO-based readout in 160-nm CMOS , 2015, 2015 IEEE Asian Solid-State Circuits Conference (A-SSCC).

[26]  Chulwoo Kim,et al.  A 0.008 ${\hbox {mm}}^{2}$ 500 $\mu{\rm W}$ 469 kS/s Frequency-to-Digital Converter Based CMOS Temperature Sensor With Process Variation Compensation , 2013, IEEE Transactions on Circuits and Systems I: Regular Papers.

[27]  Kofi A. A. Makinwa,et al.  A CMOS temperature sensor with an energy-efficient zoom ADC and an Inaccuracy of ±0.25°C (3s) from −40°C to 125°C , 2010, 2010 IEEE International Solid-State Circuits Conference - (ISSCC).

[28]  Guijie Wang,et al.  12.8 A BJT-based CMOS temperature sensor with a 3.6pJ·K2-resolution FoM , 2014, 2014 IEEE International Solid-State Circuits Conference Digest of Technical Papers (ISSCC).

[29]  Kofi A. A. Makinwa,et al.  A CMOS temperature sensor with a voltage-calibrated inaccuracy of ±0.15°C (3σ) from −55 to 125°C , 2012, 2012 IEEE International Solid-State Circuits Conference.

[30]  Kofi A. A. Makinwa,et al.  Delft University of Technology A Resistor-Based Temperature Sensor With a 0.13 pJ·K2 Resolution FoM , 2016 .

[31]  Igor M. Filanovsky.  Voltage reference using mutual compensation of mobility and threshold voltage temperature effects , 2000, 2000 IEEE International Symposium on Circuits and Systems. Emerging Technologies for the 21st Century. Proceedings (IEEE Cat No.00CH36353).