| 2026 | ISCAS | S-SSHI/SECE Hybrid Circuit with Two Diodes for Piezoelectric Devices. | Koshi Osawa, Wenqi Zhu, Hirotaka Koizumi |
| 2025 | ISCAS | A Multi-Load Capacitive Power Transfer System Using Class-E Inverter. | Kurumi Chika, Wenqi Zhu, Hirotaka Koizumi |
| 2025 | ISCAS | Load-Independent Class-E Rectifier with Variable Gain and Fixed Input Reactance. | Wenqi Zhu, Hirotaka Koizumi, Ayano Komanaka, Yutaro Komiyama, Hiroo Sekiya |
| 2023 | IECON | Load-Independent Class E | Shizuna Oshima, Hirotaka Koizumi |
| 2022 | ISCAS | HERIC Based PV Inverter Using Partial Sinewave Tracking Dual Mode Control. | Kazunori Ito, Hirotaka Koizumi |
| 2021 | ISCAS | Voltage-Source Parallel Resonant Class E Oscillator. | Takeru Kurumizawa, Hirotaka Koizumi |
| 2019 | ISCAS | Two-Stage Interleaved DC-DC Converter with Input-Parallel Output-Series Connection. | Atsushi Matsuda, Hirotaka Koizumi, Takaharu Sato |
| 2019 | IECON | A Common Ground Five-Level Inverter Using Switched Capacitor. | Kazunori Ito, Koki Takahashi, Hirotaka Koizumi |
| 2019 | IECON | Voltage-Source Parallel Resonant Class DE Inverter With Shunt Capacitor. | Yuma Mitsusada, Hirotaka Koizumi |
| 2018 | ISCAS | A Wireless Sensor Node Driving System with Bridgeless Bipolar Boost Rectifier Using Thermoelectric Energy Harvesting. | Keisuke Kimura, Keita Taeda, Shohei Niikawa, Hirotaka Koizumi |
| 2018 | ISCAS | Half-Wave Class DE Low dv/dt Rectifier Using Common-Grounded Controlled Shunt Capacitor and Its Design Approach. | Yoshikazu Sakai, Hirotaka Koizumi |
| 2018 | IECON | Class D Series-Resonant DC/DC Converter Using Switch-Controlled Capacitor with ON-OFF Feedback Control. | Taro Takamori, Tomoyuki Mannen, Hirotaka Koizumi |
| 2017 | ISCAS | A hybrid nine-level inverter with series/parallel conversion. | Yuya Nakagawa, Hirotaka Koizumi |
| 2017 | IECON | A single-input dual-output rectifier for piezoelectric energy harvesting. | Yuta Kizu, Hirotaka Koizumi |
| 2017 | IECON | Piezoelectric energy harvesting circuit using full-wave voltage doubling rectifier type series-synchronized switch harvesting on inductor. | Yoshki Ochi, Hirotaka Koizumi |
| 2017 | IECON | Current-source parallel resonant class E inverter with low peak switch current. | Akinobu Shigeno, Takashi Shimizu, Hirotaka Koizumi |
| 2017 | IECON | A thermoelectric energy harvesting system with bridgeless boost/buck-boost rectifier. | Keita Taeda, Norihiro Shiina, Keisuke Kimura, Hirotaka Koizumi |
| 2017 | IECON | Modularized double-tiered switched capacitor voltage equalizer. | Yuma Takeda, Hirotaka Koizumi |
| 2016 | ISCAS | Modularized chain structure of switched capacitor for cell voltage equalizer with T-connected bi-directional switch. | Tomoaki Shimizu, Hirotaka Koizumi |
| 2016 | IECON | Class DE voltage driven low dv/dt Rectifier with switch-controlled capacitor. | Tsuyoshi Inaba, Akifumi Nakamura, Hirotaka Koizumi |
| 2016 | IECON | A bridgeless buck AC-DC converter for piezoelectric energy harvesting. | Yuta Kizu, Kunihisa Okano, Hirotaka Koizumi |
| 2015 | ISCAS | A high step-up DC-DC converter using transformer with intrinsic voltage-doubler. | Koichi Furukawa, Taro Takiguchi, Ryuga Hosoki, Hirotaka Koizumi |
| 2015 | ISCAS | A study on effect of blocking and bypass diodes on partial shaded PV string with compensating circuit using voltage equalizer. | Kota Kato, Hirotaka Koizumi |
| 2015 | IECON | Ripple free operation of two-stage boost type DC-DC converter. | Ryuga Hosoki, Shuhei Kinjo, Hirotaka Koizumi |
| 2015 | IECON | MPPT controled piezoelectric energy harvesting circuit using synchronized switch harvesting on inductor. | Naoki Kawai, Yukito Kushino, Hirotaka Koizumi |
| 2015 | IECON | Class DE voltage-source parallel resonant inverter. | Takeshi Kondo, Hirotaka Koizumi |
| 2015 | IECON | Interleaved soft-switching multilevel boost converter with coupled inductor. | Taro Takiguchi, Koichi Furukawa, Koichi Matsumura, Hirotaka Koizumi |
| 2014 | ISCAS | Class DE current driven low di/dt rectifier. | Yutaro Minami, Hirotaka Koizumi |
| 2014 | IECON | Multistage class DE current driven low di/dt rectifier. | Yutaro Minami, Hirotaka Koizumi |
| 2014 | IECON | Modularized LC resonant switched capacitor cell voltage equalizer. | Takuya Ohno, Takahumi Suzuki, Hirotaka Koizumi |
| 2014 | IECON | Bidirectional cascaded quasi-Z-source DC-DC converter. | Takaharu Sato, Takayuki Shimo, Taro Takiguchi, Hirotaka Koizumi |
| 2014 | ISCAS | A design method for single phase Z-source inverter. | Sho Takeuchi, Naoki Yamashita, Hirotaka Koizumi |
| 2013 | IECON | Bidirectional chopper using cell voltage equalizing with flyback transformer. | Tasuku Anno, Hirotaka Koizumi |
| 2013 | IECON | Three-level buck-boost dc-dc converter with voltage-lift-type switched-inductor. | Kyohei Fukuda, Hirotaka Koizumi |
| 2013 | IECON | Double-tiered switched capacitor battery charge equalizer with chain structure. | Ryohei Fukui, Hirotaka Koizumi |
| 2013 | IECON | High-step-up dc-dc converter using voltage multiplier cell with ripple free input current. | Ryuga Hosoki, Hirotaka Koizumi |
| 2013 | IECON | Interleaved soft-switching multilevel boost converter. | Koichi Matsumura, Hirotaka Koizumi |
| 2013 | IECON | Quasi-Z-source dc-dc converter with voltage-lift technique. | Taro Takiguchi, Hirotaka Koizumi |
| 2012 | IECON | Zero current switching Type Class DE rectifier. | Tsukasa Misawa, Kazuaki Fukui, Hirotaka Koizumi |
| 2011 | ISCAS | A common grounded Z-source buck-boost converter. | Masato Asano, Daiki Abe, Hirotaka Koizumi |
| 2010 | ISCAS | A switched-capacitor inverter using series/parallel conversion. | Youhei Hinago, Hirotaka Koizumi |
| 2009 | ISCAS | Influence of Junction Capacitance of Switching Devices on Class E Rectifier. | Keiichi Sakuma, Hirotaka Koizumi |
| 2008 | ISCAS | Delta-sigma modulated class D ZCS series resonant inverter with an inductive load. | Hirotaka Koizumi |
| 2007 | ISCAS | Class DE Inverter with Asymmetric Shunt Capacitors. | Hirotaka Koizumi, Kosuke Kurokawa |
| 2006 | ISCAS | A comparison of output envelope waveforms of the delta-sigma modulated class D series resonant inverter. | Hirotaka Koizumi, Kosuke Kurokawa, Shinsaku Mori |
| 2005 | ISCAS | Thinned-out controlled class D inverter with delta-sigma modulated 1-bit driving pulses. | Hirotaka Koizumi, Kosuke Kurokawa, Shinsaku Mori |
| 2004 | ISCAS | Analysis of class D inverter with irregular driving patterns. | Hirotaka Koizumi, Kosuke Kurokawa, Shinsaku Mori |
| 2001 | ISCAS | Design of a generalized phase-controlled class E inverter. | Daisuke Kawamoto, Hiroo Sekiya, Hirotaka Koizumi, Iwao Sasase |
| 2001 | ISCAS | FM/PWM control scheme on class DE inverter for keeping high power conversion efficiency. | Hiroo Sekiya, Hirotaka Koizumi, Shinsaku Mori, Iwao Sasase |
| 1995 | ISCAS | Resonant dc/dc Converter with Class E Inverter and Class E Synchronous Rectifier Using Thinned-Out Method. | Motoki Fujii, Tadashi Suetsugu, Hirotaka Koizumi, Kokichi Shinoda, Shinsaku Mori |
| 1994 | ISCAS | A Class D Type High Frequency Tuned Power Amplifier with Class E Switching Conditions. | Hirotaka Koizumi, Minoru Iwadare, Shinsaku Mori, Kazunaga Ikeda |