A 20-MHz 1.8-W DC–DC Converter With Parallel Microinductors and Improved Light-Load Efficiency

The purpose of this paper is to show that distributing microinductors in parallel can reduce light-load losses, while also maintaining the same overall footprint area and the same effective inductance as a single microinductor. The performance of parallel microinductors is compared in a number of configurations to demonstrate which configuration provides the best overall performance in terms of circuit size, conversion efficiency, and power handling. Light-load saving techniques are implemented demonstrating the potential of parallel inductors to improve efficiency at light-load. Measured and modeled results of efficiency versus load are presented for the prototype DC-DC converters explored, and a peak efficiency of 74% is predicted for a 1.8 W, 20-MHz DC-DC converter including microinductors.