A 168µW MICS band transmitter based on injection locking for biomedical sensor nodes

Currently need for ultra low power wireless transmitters in medical applications are inevitable. In this paper a new transmitter for body-worn and implantable sensor nodes is presented. Most of the sensor nodes supply their power using energy harvesting instead of a battery, since the power earned by harvesting is limited, so the average and the peak power consumption of the sensor node must be minimized. transmitter blocks which implemented in sensor nodes are too power consuming. So we propose a new low power Binary Frequency Shift Keying (BFSK) transmitter based on sub-harmonic current mode injection locking, and edge combining technique. A 34MHz reference clock is used and the frequency of reference clock multiplied by 12 for desired carrier frequency. The phase noise of the carrier at 1MHz frequency offset is -110.3dBc, total power consumption is about 168μW. The output carrier frequency is 408MHz. BFSK modulation scheme is used at the frequency much lower than the carrier frequency in order to reduce the power consumption.

[1]  Reid R. Harrison,et al.  A wireless neural/EMG telemetry system for freely moving insects , 2010, Proceedings of 2010 IEEE International Symposium on Circuits and Systems.

[2]  Jan M. Rabaey,et al.  Ultra-Low Power Wireless Technologies for Sensor Networks , 2007 .

[3]  A. R. Newton,et al.  Alpha-power law MOSFET model and its applications to CMOS inverter delay and other formulas , 1990 .

[4]  Brian Otis,et al.  SOCWISP: A 9 μA, Addressable Gen2 Sensor Tag for Biosignal Acquisition , 2013 .

[5]  Reid R. Harrison,et al.  A Battery-Free Multichannel Digital Neural/EMG Telemetry System for Flying Insects , 2012, IEEE Transactions on Biomedical Circuits and Systems.

[6]  M. Fujishima,et al.  4.8GHz CMOS frequency multiplier with subharmonic pulse-injection locking , 2007, 2007 IEEE Asian Solid-State Circuits Conference.

[7]  Anantha Chandrakasan,et al.  A 350μW CMOS MSK transmitter and 400μW OOK super-regenerative receiver for Medical Implant Communications , 2009, 2008 IEEE Symposium on VLSI Circuits.

[8]  Fan Zhang,et al.  A 500µW neural tag with 2µVrms AFE and frequency-multiplying MICS/ISM FSK transmitter , 2009, 2009 IEEE International Solid-State Circuits Conference - Digest of Technical Papers.

[9]  Fan Zhang,et al.  A 9 $\mu$ A, Addressable Gen2 Sensor Tag for Biosignal Acquisition , 2010, IEEE Journal of Solid-State Circuits.

[10]  Brian Otis,et al.  Ultra Low-Power Integrated Circuit Design for Wireless Neural Interfaces , 2010 .

[11]  Brian P. Otis,et al.  A Sub-100 $\mu$ W MICS/ISM Band Transmitter Based on Injection-Locking and Frequency Multiplication , 2011, IEEE Journal of Solid-State Circuits.

[12]  Jaijeet S. Roychowdhury,et al.  Analytical equations for predicting injection locking in LC and ring oscillators , 2005, Proceedings of the IEEE 2005 Custom Integrated Circuits Conference, 2005..

[13]  Hoi-Jun Yoo,et al.  A low energy injection-locked FSK transceiver with frequency-to-amplitude conversion for body sensor applications , 2010, 2010 Symposium on VLSI Circuits.

[14]  Behzad Razavi,et al.  RF Microelectronics , 1997 .