Fully Integrating High-Voltage DC-DC and AC-DC Conversion

Tuur Van Daele , Filip Tavernier Analog and power management circuits

High-voltage power sources are omnipresent, such as the AC mains (e.g., 230 VRMS) and high-voltage batteries in electric cars (e.g., 400 VDC). In contrast, low-power applications like IoT, smart homes, LED drivers, and control in electric vehicles need low supply voltages. Bridging this voltage gap requires power converters with high input voltages and large conversion steps. Furthermore, the complete integration of these converters enables significant cost reduction and makes the system more reliable and compact.

Recent developments confirm this integration trend for large conversion steps, as bulky transformers in power modules are replaced by smaller and fewer external components. However, complete integration of their large off-chip inductors would suffer from a low quality factor, and for large conversion steps, these converters depend on very low duty cycles. The switched-capacitor converter (SCC) is a better candidate since it is easily integrated while operating at a 50% duty cycle regardless of the conversion step. Since switched-capacitor converters are only used at low voltages, this work investigates the challenges encountered at high voltages and proposes new topology techniques.

This work has implemented a fully integrated DC-DC converter with an input voltage of 400 V, more than 9x higher than prior state-of-the-art. At the same time, it achieves a measured power density of 119 mW/mm² at 63.6% efficiency. This advances the power density of fully integrated state-of-the-art converters by 270× while achieving the highest efficiency.

It has also implemented a fully integrated AC-DC converter to unlock additional applications powered by the ubiquitous AC mains. The measured power density is 9 mW/mm² at 55.1% efficiency. This advances the power density of fully integrated state-of-the-art AC-DC converters by >5000×.

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Tuur Van Daele
Phd student
Filip Tavernier
Academic staff

Publications about this research topic

  • T. Van Daele and F. Tavernier, “A Fully Integrated 230 VRMS-to-12 VDC AC-DC Converter Achieving 9 mW/mm2,” in 2023 IEEE Symposium on VLSI Technology and Circuits (VLSI Technology and Circuits), 2023, pp. 1–2.
  • T. Van Daele and F. Tavernier, "Fully Integrating a 400 V-to-12 V DC–DC Converter in High-Voltage CMOS," in IEEE Journal of Solid-State Circuits, doi: 10.1109/JSSC.2022.3223900.
  • T. Van Daele and F. Tavernier, "A 400-to-12 V Fully Integrated Switched-Capacitor DC-DC Converter Achieving 119 mW/mm2 at 63.6 % Efficiency," 2022 IEEE Custom Integrated Circuits Conference (CICC), Newport Beach, CA, USA, 2022, pp. 1-2, doi: 10.1109/CICC53496.2022.9772805.
  • T. Van Daele, E. De Pelecijn, T. Thielemans, M. Steyaert and F. Tavernier, "A Fully-Integrated 6:1 Cascaded Switched-Capacitor DC-DC Converter Achieving 74% Efficiency at 0.1W/mm2," 2019 15th Conference on Ph.D Research in Microelectronics and Electronics (PRIME), Lausanne, Switzerland, 2019, pp. 49-52, doi: 10.1109/PRIME.2019.8787774.
  • B. Veraverbeke, T. Thielemans, T. V. Daele and F. Tavernier, "A 240V to 47.5 V Fully Integrated Switched-Capacitor Converter in GaN Achieving 62.6% Efficiency at 220 mW/mm2," 2022 17th Conference on Ph.D Research in Microelectronics and Electronics (PRIME), Villasimius, SU, Italy, 2022, pp. 249-252, doi: 10.1109/PRIME55000.2022.9816779.

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