Abstract:
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...Show MoreMetadata
Abstract:
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.
Published in: 2022 IEEE Custom Integrated Circuits Conference (CICC)
Date of Conference: 24-27 April 2022
Date Added to IEEE Xplore: 18 May 2022
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