A Reference-Free Capacitive-Discharging Oscillator Architecture Consuming 44.4 pW/75.6 nW at 2.8 Hz/6.4 kHz

This paper presents a capacitive-discharging oscillator architecture that achieves ultra-low-power operation without a temperature-stabilized reference generator by directly relying on the RC time constants of capacitors discharging across passively-temperature-stabilized resistive elements. The architecture operates by pre-charging two capacitors to the supply voltage, and then discharging one of the capacitors through a resistive path, while the other capacitor charge-shares with a third capacitor in order to generate a reference potential for comparison to flip phases. The architecture is demonstrated with two fully-integrated implementations in two different process technologies: 250 nm and 65 nm. The 250 nm implementation employs poly resistors, operates at 6.4 kHz, consumes 75.6 nW, and achieves a temperature stability of 0.74% (148 ppm/°C) from 20°C to 80°C when measured over five samples. The 65 nm implementation employs gate-leakage resistors, operates at 2.8 Hz, consumes 44.4 pW, and achieves a temperature stability of 1260 ppm/°C across a temperature range of -40°C to 60°C over five samples. The two implementations demonstrate low-cost, low-power, and stable timing solutions at Hz-to-kHz-range frequencies for next-generation Internet-of-Things sensors.

[1]  Farrokh Ayazi,et al.  Electronically Temperature Compensated Silicon Bulk Acoustic Resonator Reference Oscillators , 2007, IEEE Journal of Solid-State Circuits.

[2]  Yong Lian,et al.  A 1-V 450-nW Fully Integrated Programmable Biomedical Sensor Interface Chip , 2009, IEEE Journal of Solid-State Circuits.

[3]  Arun Paidimarri,et al.  4.2 pW timer for heavily duty-cycled systems , 2015, 2015 Symposium on VLSI Circuits (VLSI Circuits).

[4]  David Blaauw,et al.  A cubic-millimeter energy-autonomous wireless intraocular pressure monitor , 2011, 2011 IEEE International Solid-State Circuits Conference.

[5]  Arun Paidimarri,et al.  A 120nW 18.5kHz RC oscillator with comparator offset cancellation for ±0.25% temperature stability , 2013, 2013 IEEE International Solid-State Circuits Conference Digest of Technical Papers.

[6]  Chenming Hu,et al.  Modeling gate and substrate currents due to conduction- and valence-band electron and hole tunneling [CMOS technology] , 2000, 2000 Symposium on VLSI Technology. Digest of Technical Papers (Cat. No.00CH37104).

[7]  Rahul Sarpeshkar,et al.  An analog storage cell with 5e - /sec leakage. , 2006 .

[8]  Arthur L. Chlebowski,et al.  A Miniature-Implantable RF-Wireless Active Glaucoma Intraocular Pressure Monitor , 2010, IEEE Transactions on Biomedical Circuits and Systems.

[9]  Sudipto Chakraborty,et al.  Mixed-signal integrated circuits for self-contained sub-cubic millimeter biomedical implants , 2010, 2010 IEEE International Solid-State Circuits Conference - (ISSCC).

[10]  Tadashi Maeda,et al.  A 280nW, 100kHz, 1-cycle start-up time, on-chip CMOS relaxation oscillator employing a feedforward period control scheme , 2012, 2012 Symposium on VLSI Circuits (VLSIC).

[11]  Anantha Chandrakasan,et al.  23.2 A 1.1nW energy harvesting system with 544pW quiescent power for next-generation implants , 2014, 2014 IEEE International Solid-State Circuits Conference Digest of Technical Papers (ISSCC).

[12]  Jan M. Rabaey,et al.  A Fully Integrated, 290 pJ/bit UWB Dual-Mode Transceiver for cm-Range Wireless Interconnects , 2012, IEEE Journal of Solid-State Circuits.

[13]  Michael S. McCorquodale,et al.  A 0.5-to-480MHz Self-Referenced CMOS Clock Generator with 90ppm Total Frequency Error and Spread-Spectrum Capability , 2008, 2008 IEEE International Solid-State Circuits Conference - Digest of Technical Papers.

[14]  Thomas Murphy,et al.  5.9 A 37μW dual-mode crystal oscillator for single-crystal radios , 2015, 2015 IEEE International Solid-State Circuits Conference - (ISSCC) Digest of Technical Papers.

[15]  A. Chandrakasan,et al.  Energy extraction from the biologic battery in the inner ear , 2012, Nature Biotechnology.

[16]  Akinori Matsumoto,et al.  An On-Chip CMOS Relaxation Oscillator With Voltage Averaging Feedback , 2010, IEEE Journal of Solid-State Circuits.

[17]  David Blaauw,et al.  A Millimeter-Scale Energy-Autonomous Sensor System With Stacked Battery and Solar Cells , 2013, IEEE Journal of Solid-State Circuits.

[18]  Anantha P. Chandrakasan,et al.  A 1.1 nW Energy-Harvesting System with 544 pW Quiescent Power for Next-Generation Implants , 2014, IEEE Journal of Solid-State Circuits.

[19]  David Blaauw,et al.  A Sub-nW Multi-stage Temperature Compensated Timer for Ultra-Low-Power Sensor Nodes , 2013, IEEE Journal of Solid-State Circuits.

[20]  David Blaauw,et al.  A 5.8nW, 45ppm/°C on-chip CMOS wake-up timer using a constant charge subtraction scheme , 2014, Proceedings of the IEEE 2014 Custom Integrated Circuits Conference.

[21]  David Blaauw,et al.  A 150pW program-and-hold timer for ultra-low-power sensor platforms , 2009, 2009 IEEE International Solid-State Circuits Conference - Digest of Technical Papers.

[22]  Fabio Sebastiano,et al.  Mobility-based Time References for Wireless Sensor Networks , 2012 .

[23]  Hui Wang,et al.  A 51 pW reference-free capacitive-discharging oscillator architecture operating at 2.8 Hz , 2015, 2015 IEEE Custom Integrated Circuits Conference (CICC).

[24]  David Blaauw,et al.  A sub-pW timer using gate leakage for ultra low-power sub-Hz monitoring systems , 2007, 2007 IEEE Custom Integrated Circuits Conference.

[25]  Anantha Chandrakasan,et al.  A Sub-nW 2.4 GHz Transmitter for Low Data-Rate Sensing Applications , 2014, IEEE Journal of Solid-State Circuits.

[26]  Keng-Jan Hsiao,et al.  A 32.4 ppm/°C 3.2-1.6V self-chopped relaxation oscillator with adaptive supply generation , 2012, 2012 Symposium on VLSI Circuits (VLSIC).

[27]  K. Makinwa,et al.  A low-voltage mobility-based frequency reference for crystal-less ULP radios , 2008, ESSCIRC 2008 - 34th European Solid-State Circuits Conference.

[28]  Peter R. Kinget,et al.  A Self-Duty-Cycled and Synchronized UWB Pulse-Radio Receiver SoC With Automatic Threshold-Recovery Based Demodulation , 2014, IEEE Journal of Solid-State Circuits.

[29]  David Blaauw,et al.  A 99nW 70.4kHz resistive frequency locking on-chip oscillator with 27.4ppm/ºC temperature stability , 2015, 2015 Symposium on VLSI Circuits (VLSI Circuits).

[30]  François Krummenacher,et al.  Silicon Resonator Based 3.2 $\mu$W Real Time Clock With $\pm$10 ppm Frequency Accuracy , 2010, IEEE Journal of Solid-State Circuits.

[31]  Edward A. Lee,et al.  The swarm at the edge of the cloud - A new perspective on wireless , 2011, 2011 Symposium on VLSI Circuits - Digest of Technical Papers.

[32]  David Blaauw,et al.  An Ultra-Low Power Fully Integrated Energy Harvester Based on Self-Oscillating Switched-Capacitor Voltage Doubler , 2014, IEEE Journal of Solid-State Circuits.

[33]  Anantha P. Chandrakasan,et al.  Ultra-Low-Power Short-Range Radios , 2015 .