Thin-Film Magnetic Inductor Design Strategy for Integrated Voltage Regulator

The optimal design of thin-film magnetic inductor is important to realize efficient fully Integrated Voltage Regulators (IVR). This work describes the origin of the power losses within inductor while switching at high frequency, and proposes an inductor selection strategy that is able to maximize efficiency for a desired operating condition. The optimization strategy was employed to design an inductor for IVR application which is switching at 50 MHz. To show the effectiveness of the proposed strategy, the thin-film magnetic inductor was fabricated and integrated with CMOS ASIC to realize an 8-phase IVR that yielded a peak efficiency of 85% over a wide load range of 1.5 A.