Phase-Shift Control ICs Squeeze More Efficiency from Resonant Converters
The STNRG599A and STNRG599B controllers, built for resonant-converter topologies, feature an innovative phase-shift control (PSC) that boosts power-supply no-load efficiency and delivers flicker-free deep dimming in lighting applications. STMicroelectronics’ controllers operate up to 750-kHz maximum frequency, with a wide input-voltage range to handle applications from 90 W to several hundred watts.
- The STNRG599A is optimized for power conversion, with built-in X-capacitor discharge circuitry for safety in adapters, chargers, TV power supplies, and industrial power supplies.
- The STNRG599B, without discharge circuitry, targets circuits such as lighting drivers.
Both controllers use a pair of complementary outputs to drive external high-side and low-side switches 180° out-of-phase, while ensuring zero-voltage switching across their full operating ranges.
The devices achieve precise regulation by directly controlling the phase shift between the half-bridge voltage and the resonant-tank current. This reduces the control loop’s sensitivity to LLC/LCC component tolerances, which stabilizes the burst-mode entry and exit thresholds, enhances dynamic behavior, and increases input-voltage ripple rejection.
Both controllers integrate hard-switching prevention and anti-capacitive protection. Additional features include overcurrent protection and an external automatic restart pin for flexible management of short-term overcurrent/overload/short circuit events. The controllers also offer configurable non-latched DC brown-out/brown-in protection.
Furthermore, designers can take advantage of the associated EVLG599-250WLLC evaluation board. Users can quickly explore how PSC improves performance and efficiency in AC-DC adapters, industrial DC-DC converters, and switched-mode power supplies.
The STNRG599A and STNRG599B are in production now, in a SO16N package, priced from $0.61 for orders of 1,000 pieces. The EVLG599-250WLLC is available from the eSTore or through distributors for $336.00.
About the Author
Lee Goldberg
Contributing Editor
Lee Goldberg is a self-identified “Recovering Engineer,” Maker/Hacker, Green-Tech Maven, Aviator, Gadfly, and Geek Dad. He spent the first 18 years of his career helping design microprocessors, embedded systems, renewable energy applications, and the occasional interplanetary spacecraft. After trading his ‘scope and soldering iron for a keyboard and a second career as a tech journalist, he’s spent the next two decades at several print and online engineering publications.
Lee’s current focus is power electronics, especially the technologies involved with energy efficiency, energy management, and renewable energy. This dovetails with his coverage of sustainable technologies and various environmental and social issues within the engineering community that he began in 1996. Lee also covers 3D printers, open-source hardware, and other Maker/Hacker technologies.
Lee holds a BSEE in Electrical Engineering from Thomas Edison College, and participated in a colloquium on technology, society, and the environment at Goddard College’s Institute for Social Ecology. His book, “Green Electronics/Green Bottom Line - A Commonsense Guide To Environmentally Responsible Engineering and Management,” was published by Newnes Press.
Lee, his wife Catherine, and his daughter Anwyn currently reside in the outskirts of Princeton N.J., where they masquerade as a typical suburban family.
Lee also writes the regular PowerBites series.