VCO-based ADCs for Direct RF sampling and All-electrical Sensors for Non-electrical Vital Sign Monitoring

Monday, April 18, 2016
11:45 AM to 12:45 PM
POB 2.302
Free and open to the public

In the first part of the talk, time-based ADCs using voltage-controlled oscillators will be presented for digital-intensive RF receivers. Unlike conventional delta-sigma band-pass ADCs that require accurate DACs and high speed analog circuits, the proposed architecture provides band-pass function by time-interleaving 1st-order VCO-based ADCs. Time-interleaving VCO-based ADC also increases the full scale and LSB, which reduce the magnitude of the noise transfer function. In the second part of the talk, all-electrical sensors that measure non-electrical vital signs such as pulse wave velocity (PWV) and respiration will be shown. The key techniques that we employ to obtain wire-free and all-electrical measurement are bio-impedance (BI) and analog-modulated body-channel communication (BCC) using VCO-based ADC. Measurement results of prototype chip fabricated in 0.11um CMOS process will be shown.

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SeongHwan Cho


SeongHwan Cho received the B.S. degree in electrical engineering from KAIST, Korea, and the S.M. and Ph.D. degrees in EECS from MIT, Cambridge, MA. In 2002, he joined Engim, Inc., where he was involved in data converters and phased-locked loop (PLL) design. Since 2004, he has been with KAIST in the department of EE, where he is now a professor. His research interests include analog and mixed-signal circuits for low power communication systems, bio/health-care devices and CMOS sensors. Prof. Cho received the 2009 IEEE Circuits and System Society Guillemin-Cauer Best Paper Award and 2012 ISSCC Takuo Sugano Award for Outstanding Far-East Paper. Prof. Cho has served on the TPC on several IEEE conferences, including ISSCC, Symp. on VLSI and A-SSCC. He serves as associate editor(AE) of JSSC and has served for TCAS-1.