TY - GEN

T1 - A Highly-Integrated 20-300V 0.5W Active-Clamp Flyback DCDC Converter with 76.7% Peak Efficiency

AU - Rindfleisch, Christoph

AU - Otten, Jens

AU - Wicht, Bernhard

PY - 2022

Y1 - 2022

N2 - There is a growing need for compact and energy efficient high-voltage (HV) DCDC converters with input voltages >100V for low-power applications up to 500mW. This includes loT and smart-home, supplied from the ac mains, as well as auxiliary supplies for power converters in electrical vehicles and in the field of renewable energy that operate from HV DC-link. Discrete state-of-the-art power supplies are not efficient at light loads below 500mW and are relatively large in size, Fig. 1. They typically use a passive-clamp flyback (PCF) topology (Fig. 1 bottom right) with large external components, such as power switches (QM), HV capacitors $(Cc)$, the output diode $\mathrm{D}_{\text{out}}$, and a transformer $\top$ with up to several millihenries of inductance. The passive clamp topology also suffers from losses due to the leakage inductance $L_{\text{lk}}$ and the hard switching of $\mathrm{Q}_{\mathrm{M}}$. Non-isolated HV DCDC converters with dedicated power topologies [1] achieve good power densities but are not suitable for applications that require galvanic HV isolation. Active clamp flyback (ACF) converters (Fig. 1 bottom left) allow for galvanic isolation while keeping switching losses low. However, ACF designs [2], [3] are usually optimized for high output power and still require large external components. Further, their complex control limits the light-load efficiency. This paper presents a low-power-optimized ACF IC that benefits from integration in a 180nm HV SOI technology. It offers a fully integrated power stage and provides a robust and time-precise control at faster switching speed and more compact size. This way, high light-load efficiency and good power density are achieved.

AB - There is a growing need for compact and energy efficient high-voltage (HV) DCDC converters with input voltages >100V for low-power applications up to 500mW. This includes loT and smart-home, supplied from the ac mains, as well as auxiliary supplies for power converters in electrical vehicles and in the field of renewable energy that operate from HV DC-link. Discrete state-of-the-art power supplies are not efficient at light loads below 500mW and are relatively large in size, Fig. 1. They typically use a passive-clamp flyback (PCF) topology (Fig. 1 bottom right) with large external components, such as power switches (QM), HV capacitors $(Cc)$, the output diode $\mathrm{D}_{\text{out}}$, and a transformer $\top$ with up to several millihenries of inductance. The passive clamp topology also suffers from losses due to the leakage inductance $L_{\text{lk}}$ and the hard switching of $\mathrm{Q}_{\mathrm{M}}$. Non-isolated HV DCDC converters with dedicated power topologies [1] achieve good power densities but are not suitable for applications that require galvanic HV isolation. Active clamp flyback (ACF) converters (Fig. 1 bottom left) allow for galvanic isolation while keeping switching losses low. However, ACF designs [2], [3] are usually optimized for high output power and still require large external components. Further, their complex control limits the light-load efficiency. This paper presents a low-power-optimized ACF IC that benefits from integration in a 180nm HV SOI technology. It offers a fully integrated power stage and provides a robust and time-precise control at faster switching speed and more compact size. This way, high light-load efficiency and good power density are achieved.

UR - http://www.scopus.com/inward/record.url?scp=85130723840&partnerID=8YFLogxK

U2 - 10.1109/cicc53496.2022.9772834

DO - 10.1109/cicc53496.2022.9772834

M3 - Conference contribution

AN - SCOPUS:85130723840

SN - 978-1-7281-8280-3

T3 - Proceedings of the Custom Integrated Circuits Conference

BT - 2022 IEEE Custom Integrated Circuits Conference, CICC 2022 - Proceedings

PB - Institute of Electrical and Electronics Engineers Inc.

T2 - 43rd Annual IEEE Custom Integrated Circuits Conference, CICC 2022

Y2 - 24 April 2022 through 27 April 2022

ER -