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Mohanasankar Sivaprakasam

Mohan is currently a Project Scientist in our research group. He received his Ph.D. degree in Electrical Engineering from University of California, Santa Cruz in 2006, M.S degree in Electrical Engineering from North Carolina State University in 2003 and B.Tech in Instrumentation Engineering from Anna University (India) in 2001.

His research interests are biomedical electronics for implantable, wearable and diagnostic biomedical applications, wireless microsystems for biomedical applications, neural interface electronics, neural interfaces and prostheses, and neural signal processing.

He can be reached through mohan at soe period ucsc period edu


Journal Publications:

  1. M. Chae, W. Liu, and M. Sivaprakasam, “Design Optimization for Integrated Neural Recording Systems,” To appear in IEEE Journal of Solid-State Circuits, June 2008.
  2. K. Cockerham, W. Liu, L. Crow, M. Sivaprakasam, A. Olmos, M. Oehlberg, O. Pantchenko and S. Aro, “The Application of Nano-Technology and Engineering in Medicine: A New Paradigm for Facial Muscle Reanimation,” To appear in Expert Review of Medical Devices.
  3. W. Liu and M. Sivaprakasam, “IC Technology Challenges for Implantable Devices,” Future Fab International, Volume: 20. Pages: 17 – 19, January 2006. (Invited)
  4. M. Sivaprakasam, W. Liu, G. Wang, J. D. Weiland, and M. S. Humayun, “Architecture Tradeoffs in High Density Microstimulators for Retinal Prosthesis,” IEEE Transactions on Circuits and Systems – I (Special Issue on Biomedical Circuits and Systems) Volume: 52, Pages: 2629 – 2641, December 2005.
  5. G. Wang, W. Liu, M. Sivaprakasam, and G. A. Kendir, “Design and Analysis of an Adaptive Transcutaneous Power Telemetry for Biomedical Implants,” IEEE Transactions on Circuits and Systems – I, Volume: 52, Pages: 2109 – 2117, October 2005.
  6. W. Liu, M. Sivaprakasam, G. Wang, M. Zhou, J. Granacki, J. LaCoss, and J. Wills, “Microelectronics Design for Implantable Wireless Biomimetic Microelectronic Systems,” IEEE Engineering in Medicine and Biology Magazine, Volume: 24, Pages: 66 – 74, September 2005. (Invited)
  7. G. A. Kendir, W. Liu, G. Wang, M. Sivaprakasam, R. Bashirullah, M. S. Humayun, and J. D. Weiland, “An Optimal Design Methodology for Inductive Power Link with Class-E Amplifier,” IEEE Transactions on Circuits and Systems – I, Volume: 52, Pages: 857 – 866, May 2005.
  8. M. Sivaprakasam, W. Liu, M. S. Humayun, and J. D. Weiland, “A Variable Range Bi-Phasic Current Stimulus Driver Circuitry for an Implantable Retinal Prosthetic Device,” IEEE Journal of Solid-State Circuits, Volume: 40, Pages: 763 – 771, March 2005.
  9. W. Liu, M. Sivaprakasam, P. R. Singh, R. Bashirullah, and G. Wang, “Electronic Visual Prosthesis,” Volume: 27, Pages: 986 – 995, Artificial Organs, November 2003. (Invited)


Book Chapters/Articles:

  1. W. Liu, M. Sivaprakasam, G. Wang, M. Zhou, J. D. Weiland, and M. S. Humayun, “Challenges in realizing a Chronic High Resolution Artificial Sight Device,” Artificial Sight, M. S. Humayun, J. D. Weiland, E. Greenbaum, Eds. Biological and Medical Physics/Biomedical Engineering Series, New York: Springer. (Invited)
  2. W. Liu, M. Sivaprakasam, G. Wang, M. Zhou, J. D. Weiland, and M. S. Humayun, “Development of an Intraocular Prosthesis to Benefit the Visually Impaired,” Visual Prosthetics and Ophthalmic Devices: New Hope in Sight, New Jersey: Humana Press, Inc. (Invited)
  3. W. Liu, M. Sivaprakasam, G. Wang, M. Zhou, and M. S. Humayun, “Semiconductor based Implantable Prosthetic Devices,” Wiley Handbook of Biomedical Engineering, New Jersey: John Wiley and Sons, Inc. (Invited)


Conference Publications:

  1. K. Chen, M. Chae, W. Liu, M. Sivaprakasam, and J. Kim, “A 4-channel Wearable Wireless Neural Recording System,” Submitted to IEEE International Symposium on Circuits and Systems, May 2008.
  2. M. Chae, W. Liu, Z. Yang, T. Chen, J. Kim, M. Sivaprakasam, M. R. Yuce, “A 128-Channel 6mW Wireless Neural Recording IC with On-the-fly Spike Sorting and UWB transmitter,” International Solid State Circuits Conference, February 2008.
  3. A. Olmos, M. Oehlberg, M. Gharib, M. Sivaprakasam, K. Cockerham, W. Liu, and D. Liepmann “The Effect of Chronic Denervation on Electrical, Chemical, and Electrochemical Stimulation Efficacy,” BMES Annual Fall Meeting, September 2007.
  4. M. Chae, W. Liu, and M. Sivaprakasam, “An Integrated Multi-Channel Neural Recording System,” BMES Annual Fall Meeting, September 2007.
  5. M. Gharib, A. Olmos, M. Oehlberg, M. Sivaprakasam, D. Liepmann, K. Cockerham, and W. Liu, “Development of an Indwelling Microstimulator for Neuromuscular Disease,” BMES Annual Fall Meeting, September 2007.
  6. M. Oehlberg, W. Liu, M. Sivaprakasam and O. Pantchenko, “An Implantable Microsystem for Reanimation of Eyelid Blink,” 8th Annual UC Systemwide Bioengineering Symposium, June 2007.
  7. M. Gharib, A. Olmos, M. Oehlberg, M. Sivaprakasam, W. Liu, K. Cockerham, and D. Liepmann, “Development of an Indwelling Microstimulator for Neuromuscular Disease,” 8th Annual UC Systemwide Bioengineering Symposium, June 2007.
  8. M. Chae, W. Liu, G. Wang, and M. Sivaprakasam, “Design Methodology for an Integrated Low Power Neural Recording System,” BMES Annual Fall Meeting, October 2006.
  9. M. Zhou, W. Liu, G. Wang, M. Sivaprakasam, J. D. Weiland and M. S. Humayun, “A Transcutaneous Data Telemetry System Tolerant to Power Telemetry Interference,” Annual International Conference of the IEEE EMBS, September 2006.
  10. G. Wang, W. Liu, M. Sivaprakasam, M. Zhou, J. D. Weiland and M. S. Humayun, “A Dual Band Wireless Power and Data Telemetry for Retinal Prosthesis,” Annual International Conference of the IEEE EMBS, September 2006.
  11. M. Sivaprakasam, W. Liu, G. Wang, L. Hoang, J. D. Weiland and M. S. Humayun, “Towards a Modular 32 x 32 Pixel Stimulator for Retinal Prosthesis,” Proceedings of the IEEE Life Science Systems and Application (LSSA) Workshop, July 2006.
  12. M. Sivaprakasam, W. Liu, G. Wang, M. Zhou, J. D. Weiland and M. S. Humayun, “Challenges in System and Circuit Design for High Density Retinal Prosthesis,” Proceedings of the IEEE Life Science Systems and Application (LSSA) Workshop, Pages: 28 – 29, July 2006. (Invited)
  13. W. Liu, M. Sivaprakasam, G. Wang, and M. Chae, “A Multi-channel Neural Recording System for Monitoring Shark Behavior,” IEEE International Symposium on Circuits and Systems, May 2006.
  14. M. Sivaprakasam, W. Liu, G. Wang, J. D. Weiland and M. S. Humayun, “A Programmable Discharge Circuitry with Current Limiting Capability for a Retinal Prosthesis,” Annual International Conference of the IEEE EMBS, September 2005.
  15. G. Wang, W. Liu, M. Sivaprakasam, M. Zhou, J. D. Weiland and M. S. Humayun, “A Wireless Phase Shift Keying Transmitter with Q-Independent Phase Transition Time,” Annual International Conference of the IEEE EMBS, September 2005.
  16. G. Wang, W. Liu, M. Sivaprakasam, M. S. Humayun, and J. D. Weiland, “Power Supply Topologies for Biphasic Stimulation in Inductively Powered Implants,” Proceedings of the IEEE International Symposium on Circuits and Systems, Pages: 2743 – 2746, May 2005.
  17. M. Zhou, W. Liu, and M. Sivaprakasam, “A Closed-Form Delay Formula for On-Chip RLC Interconnects in Current-Mode Signaling,” Proceedings of the IEEE International Symposium on Circuits and Systems, Pages: 1082 – 1085, May 2005.
  18. W. Liu, W. Fink, M. Tarbell, and M. Sivaprakasam, “Image Processing Enhanced Electrical Stimulation of the Retina in Visual Prostheses,” Proceedings of the IEEE International Symposium on Circuits and Systems, Pages: 2927 – 2930, May 2005. (Invited)
  19. M. Sivaprakasam, W. Liu, M. S. Humayun, and J. D. Weiland, “Power Efficient Multiple Voltage Stimulation for Implantable Retinal Prosthesis,” Proceedings of the 3rd Annual International IEEE EMBS Special Topic Conference on Microtechnologies in Medicine and Biology, Pages: 104 – 107, May 2005.
  20. W. Liu, M. Sivaprakasam, G. Wang, M. Zhou, J. D. Weiland, and M. S. Humayun, “Microelectronics for an Implantable Epiretinal Prosthesis,” Association for Research in Vision and Ophthalmology Annual Meeting, Abstract B295, May 2005.
  21. E. Basham, W. Liu, and M. Sivaprakasam, “Functional Magnetic Stimulation for and Epiretinal Prosthesis,” Association for Research in Vision and Ophthalmology Annual Meeting, Abstract B254, May 2005.
  22. W. Liu, M. Sivaprakasam, G. Wang, M. Zhou, J. D. Weiland, M. S. Humayun, “Challenges in Realizing a Chronic High Resolution Artificial Sight Device,” U.S. Department of Energy (DOE) International Symposium on Artificial Sight, April 2005. (Invited)
  23. M. Sivaprakasam, W. Liu, G. Wang, M. Zhou, J. D. Weiland, and M. S. Humayun, “Architecture Tradeoffs in High Density Microstimulators for Retinal Prosthesis,” Proceedings of the International IEEE EMBS Conference on Neural Engineering, Pages: 466 – 469, March 2005.
  24. G. Wang, W. Liu, M. Sivaprakasam, J. D. Weiland, and M. S. Humayun, “High Efficiency Wireless Power Transmission with Digitally Configurable Stimulation Voltage for Retinal Prosthesis,” Proceedings of the International IEEE EMBS Conference on Neural Engineering, Pages: 543 – 546, March 2005.
  25. M. Kazemi, E. Basham, M. Sivaprakasam, G. Wang, D. Rodger, J. Weiland, Y. C. Tai, W. Liu, M. Humayun, “A Test Microchip for Evaluation of Hermetic Packaging Technology for Biomedical Prosthetic Implants,” Proceedings of the International Conference of the IEEE Engineering in Medicine and Biology Society, Volume: 2, Pages: 4093 – 4095, September 2004.
  26. P. R. Singh, W. Liu, M. Sivaprakasam, M. Humayun, and J. Weiland, “A Matched biphasic Microstimulator for an implantable Retinal Prosthetic device,” Proceedings of the IEEE International Symposium on Circuits and Systems, Volume: 4, Pages: 1 – 5, May 2004.
  27. G. Wang, W. Liu,  R. Bashirullah, M. Sivaprakasam, G. A. Kendir, Y. Ji, M. S. Humayun, and J. D. Weiland, “A Closed Loop Transcutaneous Power Transfer System for Implantable Devices with Enhanced Stability," Proceedings of the IEEE International Symposium on Circuits and Systems, Volume: 4, Pages: 17 - 20, May 2004.
  28. R. Bashirullah, W. Liu, Y. Ji, A. Kendir, M. Sivaprakasam, G. Wang, and B. Pundi, “A Smart Bi-Directional Telemetry Unit for Retinal Prosthetic Device,” Proceedings of the IEEE International Symposium on Circuits and Systems, Volume: 5, Pages: 5 – 8, May 2003.

Invention Disclosures:

  1. “Highly Versatile Programmable Biostimulator for Neural Applications” (with W. Liu, T. Chen, K. Chen), UCSC invention disclosure, April 2008.
  2. “Method, Architecture and Circuit Implementation for Ultra-Wideband Wireless Transceiver for Neural Recording Applications” (with W. Liu, M. Chae, M. Yuce), UCSC invention disclosure, March 2008.
  3. “Specifications and architecture of a low power, high voltage, high density implantable retinal prosthetic device” (with W. Liu, M. Chae, J. Kim, J. Weiland, M. Humayun), UCSC invention disclosure, March 2008
  4. “System architectures and tradeoffs involved in the design of high density retinal stimulators” (with W. Liu, G. Wang), UCSC invention disclosure, September 2005, UC Case No. 2006-208-1.
  5. “Method and theory of creating virtual electrodes for stimulation in a retinal prosthetic implant” (with W. Liu, Z. Yang), UCSC invention disclosure, July 2005.
  6. “Communication protocol for wireless transmission of data to an implantable retinal prosthetic device,” (with W. Liu), UCSC invention disclosure, January 2005, UC Case No. 2005-389-1.
  7. “Method, architecture and circuit implementation for discharging electrode sites with discharge current limited profiles which are programmable” (with W. Liu), UCSC invention disclosure, October 2004, UC Case No. 2005-202-1.
  8. “Method, architecture and circuit implementation for providing variable-range stimulus for retinal prosthetic implant” (with W. Liu), UCSC invention disclosure, October 2004, UC Case No. 2005-204-1.
  9. “Adaptive transcutaneous wireless inductive power transfer system for biomedical implants,” (with G. Wang, W. Liu, M. Humayun, J. Weiland), UCSC invention disclosure, October 2004, UC Case No. 2004-592-1.
  10. “Bioelectronic Pill,” (with W. Liu), UCSC invention disclosure, May 2004, UC Case No. 2004-620-1.



Grant Proposals co-written with Prof. Wentai Liu:

  1. “Short Range Wireless Medical Sensor Network,” Funded by UC MICRO (PI: Prof. Wentai Liu)
  2. “Elasmobranch Brain Machine Interface,” Funded by DARPA (Co-PI: Prof. Wentai Liu)
  3. “A Hybrid Electrochemical Microstimulator Implant for Denervated Muscles,” Funded by DOD (Co-PI: Prof. Wentai Liu)
  4. “Sub-Cellular Scale Neuroengineering for Nerve Repair,” Declined by NSF due to budget limitations (Co-PI: Prof. Wentai Liu)
  5. “Artifical Retina Project: Wireless Link and Microelectronics,” Funded by DOE (PI: Prof. Wentai Liu)
  6. “Understanding, Modeling and Simulation of Sub-symbolic Intelligence in Adaptive Control, Optimization and Prediction,” Declined by NSF (PI: Prof. Wentai Liu)

Professional Service:

  1. Special acknowledgment from the Editors citing “Outstanding Professional Service” for Proceedings of the IEEE Special Issue on Implantable Biomimetic Microelectronics Systems, July 2008.
  2. Session Co-Chair for “Neural Engineering: Integrated Circuits for Neural Recording and Stimulation” in 2007 Annual Fall BMES Meeting, September 2007.
  3. Session Co-Chair in IEEE Life Science Systems and Applications (LSSA) Workshop, July 2006.
  4. Session Chair for “Biomedical Systems” in IEEE International Symposium on Circuits and Systems, May 2005.

Technical Reviewer:

IEEE Journal of Solid-State Circuits, IEEE Transactions on Circuit and Systems – I, IEEE Transactions on Biomedical Engineering, IEEE Transactions on Biomedical Circuits and Systems, IEEE Transactions on Neural Systems and Rehabilitation Engineering, Proceedings of the IEEE, IEE Electronics Letters, IEEE International Symposium on Circuits and Systems, IEEE Biomedical Circuits and Systems Conference, IEEE/NLM Life Sciences Systems and Applications Workshop, IEEE International Midwest Symposium on Circuits and Systems.

Talks and Poster Presentations:

  1. “An Integrated Multi-Channel Neural Recording System,” 2007 Annual Fall BMES Meeting, Los Angeles, September 2007. (Talk)
  2. “Workshop on Circuit Design for Implantable Biomedical Applications,” Anna University, Chennai, India, July 2007. (Invited Talk)
  3. “Power and Data Telemetry,” U.S. Department of Energy (DOE) PI Review, Bethesda, U. S., December 2006. (Talk)
  4. “A Dual Band Wireless Power and Data Telemetry for Retinal Prosthesis,” Annual International Conference of the IEEE EMBS, New York, U. S., September 2006. (Talk)
  5. “Challenges in System and Circuit Design for High Density Retinal Prosthesis,” IEEE Life Science Systems and Applications (LSSA) Workshop, Bethesda, U. S., July 2006. (Invited Talk)
  6. “Image Processing Enhanced Electrical Stimulation of the Retina in Visual Prostheses,” IEEE International Symposium on Circuits and Systems, Kobe, Japan, May 2005. (Invited Talk)
  7. “Power Supply Topologies for Biphasic Stimulation in Inductively Powered Implants,” IEEE International Symposium on Circuits and Systems, Kobe, Japan, May 2005. (Poster)
  8. “A Closed-Form Delay Formula for On-Chip RLC Interconnects in Current-Mode Signaling,” IEEE International Symposium on Circuits and Systems, Kobe, Japan, May 2005. (Poster)
  9. “Microelectronics for an Implantable Epiretinal Prosthesis,” Association for Research in Vision and Ophthalmology Annual Meeting, Fort Lauderdale, U. S., May 2005. (Poster)
  10. “Microelectronics Design for 256-channel Retinal Prosthetic Device,” U.S. Department of Energy (DOE) PI Review, Fort Lauderdale, U. S., April 2005. (Talk)
  11. “Challenges in Realizing a Chronic High Resolution Artificial Sight Device,” U.S. Department of Energy (DOE) International Symposium on Artificial Sight, Fort Lauderdale, U. S., April 2005. (Poster)
  12. “Architecture Tradeoffs in High Density Microstimulators for Retinal Prosthesis,” International IEEE EMBS Conference on Neural Engineering, Washington D.C., U. S., March 2005. (Talk)
  13. “A Matched Biphasic Microstimulator for an Implantable Retinal Prosthetic Device,” IEEE International Symposium on Circuits and Systems, Vancouver, Canada, May 2004. (Talk)
  14. “A Smart Bi-Directional Telemetry Unit for Retinal Prosthetic Device,” IEEE International Symposium on Circuits and Systems, Bangkok, Thailand, May 2003. (Talk)
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