Phase-Shift Control ICs Squeeze More Efficiency From Resonant Converters

Why It Matters

The enhanced efficiency and tighter regulation reduce energy waste in high‑volume adapters and LED drivers, directly impacting OEM cost and sustainability goals. Faster adoption of phase‑shift control can accelerate market shift toward greener power electronics.

Key Takeaways

• STNRG599A adds X‑capacitor discharge for safety.
• STNRG599B optimized for flicker‑free lighting dimming.
• Phase‑shift control enables zero‑voltage switching up to 750 kHz.
• Improves no‑load efficiency and reduces input ripple.
• EVLG599‑250WLLC board costs $336 for rapid prototyping.

Pulse Analysis

Resonant converters have become a cornerstone of modern power‑electronics design, especially in high‑density adapters and LED lighting. By shifting the phase between the half‑bridge voltage and the resonant‑tank current, STMicroelectronics’ new controllers achieve zero‑voltage switching across a broad frequency range, cutting switching losses and extending component life. This approach also mitigates the sensitivity of traditional LLC/LCC topologies to component tolerances, delivering more predictable performance in burst‑mode operation.

The STNRG599A and STNRG599B differentiate themselves through targeted feature sets. The 599A integrates an X‑capacitor discharge circuit, simplifying safety compliance for chargers, TV power supplies, and industrial converters. Meanwhile, the 599B omits this circuitry to maximize efficiency in lighting drivers, supporting flicker‑free deep dimming. Both ICs include over‑current protection, anti‑capacitive safeguards, and configurable brown‑out protection, allowing designers to streamline bill‑of‑materials while meeting stringent reliability standards.

From a business perspective, the $0.61 price point for bulk orders makes these controllers attractive for OEMs seeking cost‑effective efficiency gains. The accompanying EVLG599‑250WLLC evaluation board accelerates development cycles, reducing time‑to‑market for next‑generation power solutions. As regulatory pressure mounts for greener electronics, the ability to boost no‑load efficiency and lower input‑ripple can translate into measurable energy savings at scale, positioning STMicroelectronics as a key enabler of sustainable power‑electronics ecosystems.