In an effort to meet the rising energy demands of data centers, engineers at the University of California San Diego have developed a new chip design that could improve how graphics processing units (GPUs) convert and manage power. The technology demonstrates a more efficient way to perform a critical task in electronics: converting high voltages into lower levels required by computing hardware. In lab tests, a prototype chip performed the type of voltage conversion used in modern data centers with high efficiency.
The advance, published in Nature Communications , could lead to the development of smaller, more energy-efficient systems for advanced computing.
The chip design offers a new approach to improving the performance of a circuit component known as a DC-DC step-down converter, which is found in nearly all electronics. The step-down converter acts as a protective bridge between power sources and sensitive circuits. It transforms a high input voltage into the lower voltage each component in the circuit precisely needs to operate safely. For example, data centers often distribute power at 48 volts, while processors in GPUs need much lower voltages, typically between 1 and 5 volts.
However, converting between these levels efficiently, and within limited space, has become increasingly difficult as computing demands grow.
Traditional step-down converters, for instance, lose efficiency and struggle to deliver enough current when the gap between input and output voltage is large. Most step-down converters rely on magnetic components such as inductors, which, while effective, are approaching their physical performance limits and are growing difficult to scale further. "We've gotten so good at designing inductive converters that there's not really much room left to improve them to meet future needs," said study senior author Patrick Mercier, professor in the Department of Electrical and Computer Engineering at the UC San Diego Jacobs School of Engineering.
To address this challenge, Mercier and members of his research group, including study first author Jae-Young Ko, an electrical and computer engineering Ph.D. student at UC San Diego, explored a promising alternative: piezoelectric resonators, which are tiny devices that store and transfer energy through mechanical vibrations. Piezoelectric-based converters could potentially be smaller, more energy dense, more efficient and easier to manufacture at scale. "They have a lot of room to grow and have the potential to deliver better performance than anything that's come before them," Mercier said.
However, early versions of piezoelectric-based converters have struggled to maintain efficiency and deliver enough power when handling large voltage differences.
In this study, the team developed an improved step-down converter that combines a piezoelectric resonator with small, commercially available capacitors arranged in a strategic way. This new circuit design allows the converter to handle larger voltage conversions more effectively. The team implemented the design in a prototype chip. In tests, it converted 48 volts down to 4.8 volts — a level commonly required in data centers — with a peak efficiency of 96.2 percent. The chip also delivered about four times more output current than earlier piezoelectric-based designs.
There are several advantages with this hybrid circuit design: it creates multiple pathways for power to flow; reduces wasted energy; and eases the workload on the resonator. As a result, it boosts both efficiency and power delivery with only a small increase in size.
Although the technology is still in its early stages, the researchers say it represents an important step toward overcoming the limitations of today's power converters. Future work will focus on improving materials, circuit design and packaging. Because piezoelectric resonators physically vibrate, they cannot be soldered onto circuit boards using conventional approaches, and will require different strategies to integrate them into electronic systems, Mercier explained.
"Piezoelectric-based converters aren't quite ready to replace existing power converter technologies yet," Mercier added. "But they offer a trajectory for improvement. We need to continue to improve on multiple areas — materials, circuits and packaging — to make this technology ready for data center applications."
Full study: " A Hybrid Piezoelectric Resonator-based DC-DC Converter "
This project was supported in part by the Power Management Integration Center (PMIC), an Industry-University Cooperative Research Center (IUCRC) funded by the National Science Foundation (award number 2052809).
