Matthew Anthony Wilkowski

Issues and advances in high-frequency magnetics for switching power supplies

Magnetic components have been and will continue to be an essential element in power conversion and management circuits. Due to this pivotal role, magnetic components have seen continuous efforts to develop materials, winding structures, and manufacturing and assembly techniques toward the never ending goals of high efficiency, smaller size, and automated manufacturing. The authors present an up-to-date view as well as an outlook for the future covering the technologies that have enabled the advanced in magnetic components for power electronics in telecommunications. Finally, they also provide their view on emerging technologies in this field in line with broader developments in the telecommunications, electronics and semiconductor industries.

A 20MHz monolithic DC-DC converter manufactured with the first commercially viable silicon magnetics technology

This paper presents a Power System on Chip (Power-SoC), switch-mode DC-DC synchronous buck converter with switching frequency of 20 MHz, which monolithically integrates high-speed power MOSFET switches, controller and drive circuits, the compensation network, and more importantly, a silicon-based inductor. The new device implements a type III voltage mode control scheme with wide loop bandwidth, which offers ultra-fast transient with tiny small ceramic capacitor and ultra-low ripple (> 8mV peak-peak). The compact design facilitates encapsulation in a 3×4.5×0.9 mm DFN package, while its high efficiency eliminates the necessity of a heat sink. The fully integrated design only requires input and output capacitors, and offers an excellent size and cost-effective alternative to a comparable LDO for high-speed transient and noise sensitive applications. The controller chip is fabricated in a standard 0.25µm CMOS process including high speed, high voltage LDMOS devices used for the integrated power switches. The proprietary magnetics-on-silicon inductor is implemented using a magnetic alloy on silicon die mounted on a substrate coil-in-package to achieve an ultrasmall solution. Performance results show that the new converter can provide up to 1000mA of continuous DC output current, at up to 90% peak efficiency in Pulse-Width-Modulation (PWM) mode. The device is in production with the first commercially viable silicon magnetics technology deployed in a standard foundry.