Blind source separation and chaotic analysis of EEG for judgment of brain death. - Gen Hori; Kazuyuki Aihara; Yoshikuni Mizuno; Yasuyuki Okuma (Artif. Life Robotics, 2001)

A novel UWB impulse-radio transmitter with all-digitally-controlled pulse generator. - Takayasu Norimatsu; Ryosuke Fujiwara; Masaru Kokubo; Masayuki Miyazaki; Yasuyuki Okuma; Miki Hayakawa; Shinsuke Kobayashi; Noboru Koshizuka; Ken Sakamura (ESSCIRC, 2005)

0.7-GHz-Bandwidth DS-UWB-IR System for Low-Power Wireless Communications. - Ryosuke Fujiwara; Akira Maeki; Kenichi Mizugaki; Goichi Ono; Tatsuo Nakagawa; Takayasu Norimatsu; Masaru Kokubo; Masayuki Miyazaki; Yasuyuki Okuma; Miki Hayakawa; Shinsuke Kobayashi; Noboru Koshizuka; et al. (IEICE Trans. Commun., 2008)

0.5-V input digital LDO with 98.7% current efficiency and 2.7-µA quiescent current in 65nm CMOS. - Yasuyuki Okuma; Koichi Ishida; Yoshikatsu Ryu; Xin Zhang 025; Po-Hung Chen; Kazunori Watanabe; Makoto Takamiya; Takayasu Sakurai (CICC, 2010)

3-D System Integration of Processor and Multi-Stacked SRAMs Using Inductive-Coupling Link. - Makoto Saen; Kenichi Osada; Yasuyuki Okuma; Kiichi Niitsu; Yasuhisa Shimazaki; Yasufumi Sugimori; Yoshinori Kohama; Kazutaka Kasuga; Itaru Nonomura; Naohiko Irie; Toshihiro Hattori; Atsushi Hasegawa; et al. (IEEE J. Solid State Circuits, 2010)

A 80-mV input, fast startup dual-mode boost converter with charge-pumped pulse generator for energy harvesting. - Po-Hung Chen; Koichi Ishida; Xin Zhang 025; Yasuyuki Okuma; Yoshikatsu Ryu; Makoto Takamiya; Takayasu Sakurai (A-SSCC, 2011)

A 95mV-startup step-up converter with Vth-tuned oscillator by fixed-charge programming and capacitor pass-on scheme. - Po-Hung Chen; Koichi Ishida; Katsuyuki Ikeuchi; Xin Zhang 025; Kentaro Honda; Yasuyuki Okuma; Yoshikatsu Ryu; Makoto Takamiya; Takayasu Sakurai (ISSCC, 2011)

0.18-V Input Charge Pump with Forward Body Bias to Startup Boost Converter for Energy Harvesting Applications. - Po-Hung Chen; Koichi Ishida; Xin Zhang 025; Yasuyuki Okuma; Yoshikatsu Ryu; Makoto Takamiya; Takayasu Sakurai (IEICE Trans. Electron., 2011)

0.5-V Input Digital Low-Dropout Regulator (LDO) with 98.7% Current Efficiency in 65 nm CMOS. - Yasuyuki Okuma; Koichi Ishida; Yoshikatsu Ryu; Xin Zhang 025; Po-Hung Chen; Kazunori Watanabe; Makoto Takamiya; Takayasu Sakurai (IEICE Trans. Electron., 2011)

A Variable Output Voltage Switched-Capacitor DC-DC Converter with Pulse Density and Width Modulation (PDWM) for 57% Ripple Reduction at Low Output Voltage. - Xin Zhang 025; Yu Pu; Koichi Ishida; Yoshikatsu Ryu; Yasuyuki Okuma; Po-Hung Chen; Takayasu Sakurai; Makoto Takamiya (IEICE Trans. Electron., 2011)

A 120-mV input, fully integrated dual-mode charge pump in 65-nm CMOS for thermoelectric energy harvester. - Po-Hung Chen; Koichi Ishida; Xin Zhang 025; Yasuyuki Okuma; Yoshikatsu Ryu; Makoto Takamiya; Takayasu Sakurai (ASP-DAC, 2012)

13% Power reduction in 16b integer unit in 40nm CMOS by adaptive power supply voltage control with parity-based error prediction and detection (PEPD) and fully integrated digital LDO. - Koji Hirairi; Yasuyuki Okuma; Hiroshi Fuketa; Tadashi Yasufuku; Makoto Takamiya; Masahiro Nomura; Hirofumi Shinohara; Takayasu Sakurai (ISSCC, 2012)

A 0.45-V input on-chip gate boosted (OGB) buck converter in 40-nm CMOS with more than 90% efficiency in load range from 2µW to 50µW. - Xin Zhang 025; Po-Hung Chen; Yoshikatsu Ryu; Koichi Ishida; Yasuyuki Okuma; Kazunori Watanabe; Takayasu Sakurai; Makoto Takamiya (VLSIC, 2012)

Startup Techniques for 95 mV Step-Up Converter by Capacitor Pass-On Scheme and VTH-Tuned Oscillator With Fixed Charge Programming. - Po-Hung Chen; Koichi Ishida; Katsuyuki Ikeuchi; Xin Zhang 025; Kentaro Honda; Yasuyuki Okuma; Yoshikatsu Ryu; Makoto Takamiya; Takayasu Sakurai (IEEE J. Solid State Circuits, 2012)

An 80 mV Startup Dual-Mode Boost Converter by Charge-Pumped Pulse Generator and Threshold Voltage Tuned Oscillator With Hot Carrier Injection. - Po-Hung Chen; Xin Zhang 025; Koichi Ishida; Yasuyuki Okuma; Yoshikatsu Ryu; Makoto Takamiya; Takayasu Sakurai (IEEE J. Solid State Circuits, 2012)

A 1-V-Input Switched-Capacitor Voltage Converter With Voltage-Reference-Free Pulse-Density Modulation. - Xin Zhang 025; Yu Pu; Koichi Ishida; Yoshikatsu Ryu; Yasuyuki Okuma; Po-Hung Chen; Kazunori Watanabe; Takayasu Sakurai; Makoto Takamiya (IEEE Trans. Circuits Syst. II Express Briefs, 2012)

A low voltage buck DC-DC converter using on-chip gate boost technique in 40nm CMOS. - Xin Zhang 025; Po-Hung Chen; Yoshikatsu Ryu; Koichi Ishida; Yasuyuki Okuma; Kazunori Watanabe; Takayasu Sakurai; Makoto Takamiya (ASP-DAC, 2013)

A 0.6 V Input CCM/DCM Operating Digital Buck Converter in 40 nm CMOS. - Xin Zhang 025; Po-Hung Chen; Yasuyuki Okuma; Koichi Ishida; Yoshikatsu Ryu; Kazunori Watanabe; Takayasu Sakurai; Makoto Takamiya (IEEE J. Solid State Circuits, 2014)

27.6 Single-chip 3072ch 2D array IC with RX analog and all-digital TX beamformer for 3D ultrasound imaging. - Yusaku Katsube; Shinya Kajiyama; Takuma Nishimoto; Tatsuo Nakagawa; Yasuyuki Okuma; Yohei Nakamura; Takahide Terada; Yutaka Igarashi; Taizo Yamawaki; Toru Yazaki; Yoshihiro Hayashi; Kazuhiro Amino; et al. (ISSCC, 2017)

Single-Chip 3072-Element-Channel Transceiver/128-Subarray-Channel 2-D Array IC With Analog RX and All-Digital TX Beamformer for Echocardiography. - Yutaka Igarashi; Shinya Kajiyama; Yusaku Katsube; Takuma Nishimoto; Tatsuo Nakagawa; Yasuyuki Okuma; Yohei Nakamura; Takahide Terada; Taizo Yamawaki; Toru Yazaki; Yoshihiro Hayashi; Kazuhiro Amino; et al. (IEEE J. Solid State Circuits, 2019)