Optimization and comparison of double-layer planar inductors in high frequency monolithic DC/DC converters

A global optimization algorithm is presented. The key technologies of geometric programming are applied to the on-chip double-layer inductors used in fully integrated DC/DC converters. This algorithm can globally and efficiently solve the tradeoffs between the inductor competing objectives, such as the quality factor and the area. Based on the physical model, the 10-40 nH series square and circle double-layer planar inductors are globally optimized using geometric programming, and the geometric programming formed analytical expressions are given too. From the optimized results, under the same constrains, the maximum quality factor of the circlar inductors is about 20% higher than that of the square inductors with the same inductance. However, there is not observable difference of resonant frequency between square and circle inductors.