Ultra-compact Single-stage 48 V-to-Sub-1 V Converter with Adaptive Soft-switch Control

Background:

Modern computing, telecom, and edge systems increasingly rely on 48 V power distribution to improve efficiency and reduce conduction losses. However, stepping down from 48 V to sub-1 V at hundreds of amperes remains a challenge due to limitations in traditional multi-stage, resonant, and switched-capacitor converter architectures. These systems suffer from high losses, complex control schemes, large footprints, and poor transient response under dynamic loads. A simplified, single-stage solution capable of fast, efficient, and compact 48 V-to-sub-1 V power conversion is needed to support high-performance processors and AI workloads.

Technology Overview:

This invention introduces a single-stage isolated half-bridge point-of-load converter operating under quasi-peak cycle-by-cycle current control. The topology achieves soft-switching through zero-voltage switching (ZVS) on the primary side and zero-current switching (ZCS) on the secondary synchronous rectifiers. A transformer–inductor link provides galvanic isolation and high power density with a purely capacitive output filter. The circuit incorporates a saturable reactor that dynamically adjusts inductance to limit switching frequency rise at light loads. Burst-mode operation maintains high efficiency under idle conditions. Integrated sensorless adaptive droop control enables precise voltage regulation without external current sensors, reducing circuit complexity while enhancing transient response and thermal stability.

Advantages:

• Maintains >85% efficiency under light-load conditions via saturable reactor and burst-mode control
• Reduces component count using a single-stage half-bridge design with only four switches and one transformer
• Enables full-range soft-switching (ZVS/ZCS) for reduced EMI and switching losses
• Achieves ultra-fast transient response with quasi-peak cycle-by-cycle current control
• Provides high power density through isolated inductive link and capacitive output filter
• Implements sensorless adaptive droop control for precise voltage regulation
• Limits switching frequency to 900 kHz at light loads for improved EMI and thermal performance
• Reduces system cost by eliminating extra magnetic and passive stages

Applications:

• High-performance computing and data-center CPU/GPU/AI power regulation
• 48 V distributed power systems in telecom and 5G base stations
• Edge computing, IoT, and embedded systems requiring compact PoL converters
• Automotive ADAS and infotainment compute modules using 48 V architectures
• Power-over-Ethernet (PoE) smart devices requiring efficient light-load operation

Intellectual Property Summary:

• United States – 63/393,801 – Provisional – Filed 07/29/2022 – Converted
• United States – 18/353,062 – Utility – Filed 07/14/2023 – Publication No. US 2024/0048061 A1 – Filed 03/19/2024 – Status: Filed

Stage of Development:

Prototype validated under 48 V input and dynamic load transients.

Licensing Status:

This technology is available for licensing.

Licensing Potential:

Ideal for power electronics manufacturers, data-center system integrators, and automotive electronics developers seeking compact, cost-effective, and high-efficiency 48 V-to-sub-1 V converter solutions.

Additional Information:

Prototype testing data and dynamic transient response performance metrics available upon request.