Analysis of Microinductor Performance in a 20-100 MHz DC/DC Converter

• Published in: IEEE transactions on power electronics Vol. 24; no. 9; pp. 2212 - 2218
• Main Authors: Meere, R., O'Donnell, T., Bergveld, H.J., Ningning Wang, O'Mathuna, S.C.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.09.2009; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Analysis; Applied sciences; Chips; Circuit properties; Circuits; Converters; DC-DC power converters; DC/DC conversion; Direct current; Electric currents; Electric potential; Electric power; Electric, optical and optoelectronic circuits; Electrical engineering. Electrical power engineering; Electronic circuits; Electronics; Exact sciences and technology; Frequency response; high frequency; Inductance; Inductors; low profile; Magnetic cores; Magnetic devices; magnetic-core inductors; Performance analysis; Power electronics, power supplies; Power generation; Power loss; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Semiconductor thin films; Signal convertors; Silicon; Thin film inductors; Thin films; Transformers and inductors; Voltage; Performance evaluation; Power converter; Output power; Precision engineering; DC/DC conversion; low profile; Chip; Inductor; Power range milli W; Inductance; magnetic-core inductors; Magnetic material; Output voltage; Power losses; Frequency response; Direct current convertor; Power electronics; Low power; DC-DC power convertors; High power; Thin film inductors; Magnetic core; Low-power electronics; High frequency; Comparative study
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2009.2021942

This paper presents a low-profile thin-film microfabricated inductor on silicon and its performance in a high-frequency low-power DC/DC converter. The design of the inductors has focused on maximizing efficiency while maintaining a relatively flat frequency response up to 30 MHz. The inductance at 20 MHz is approximately 150 nH with a resistance of 1.8 ¿. The performance of the microinductor has been compared to two conventional commercially available 150-nH chip inductors. One of the chip inductors has a magnetic-material core and the other is an air core. The maximum efficiency of the microinductor, which relates the power loss of the microinductor to output power loss of the converter, is measured to be approximately 93% at 20 MHz. The low-power DC/DC converter operates in the tens of milliwatts output power range, with an input voltage of 1.8 V and an output voltage programmable between 0 and 1.8 V. The converter maximum efficiency when using the microinductor on silicon is 78.5% at 20 MHz, which is approximately 2% lower than the efficiency using the conventional chip inductors.