Multiphase buck converters are widely used in 12V applications such as data centers, artificial intelligence (AI) systems, and communication infrastructure. A common theme among these use cases is the need to improve efficiency without compromising performance or increasing physical space.
A promising approach is to use coupled inductors (CL). By using phase to phase mutual inductance technology, CL can effectively eliminate current ripple, thereby significantly improving efficiency while maintaining compatibility with traditional layouts.
This article will briefly outline the challenges faced by designers of multiphase buck converters in terms of efficiency and layout. Then introduce CL, provide experimental results to verify the efficiency improvement, and demonstrate how to apply CL in Analog Devices converters.
The efficiency challenge of traditional multiphase buck converters
In high-performance computing and communication systems, the efficiency loss of power transmission can have a significant impact on system cost, reliability, and thermal management. Designers of traditional multiphase voltage regulators often face challenges in this regard, especially under light load conditions where switch and AC losses become more pronounced.
Meanwhile, power level layout and mechanical limitations also limit the options for improving performance. In many systems, the upgrade space for component size is extremely limited, and when faced with universal pad strategies, it is often difficult to adjust the layout of printed circuit boards (PCBs).
Therefore, there is a strong interest in methods that can achieve higher efficiency without significant modifications to the power architecture. Ideally, such solutions should maintain the same pad layout, allow the use of existing output capacitors (CO), and maintain transient performance under various load conditions.
CL meets these requirements by reducing ripple and improving switch losses, all of which have the same pad layout as traditional designs.