A DC/DC boost converter toward fully on-chip integration using new micromachined planar inductors

Abstract

A surface mounted DC/DC boost converter using new micromachined planar inductors has been designed, implemented and characterized for complete on-chip integration. Microfabricated inductors without an air gap in the magnetic core and with an air gap of 100 /spl mu/m in the magnetic core have been realized and used in the boost converter. The converter using the inductor with the air gap shows better performance than that using the inductor with no air gap in the core. This can be attributed to the better quality factor and suppression of the DC current saturation for large loads for the inductor with air gap in its core. The converter shows the best performance in the driving frequency range of 3 MHz to 10 MHz for a load of 100 k/spl Omega/. An input of 3 V was boosted up to 6.55 V in the above switching frequency range and load condition. A maximum achievable voltage conversion factor of 2.2 was obtained from the converter employing the inductor with an air gap of 100 /spl mu/m in its magnetic core.