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Laminated Metallic Magnetic Cores

Power Supply on a Chip

Project Overview

We are working in collaboration with Texas Instruments towards creating compact, low-profile power adapters and power bricks using materials and tools adapted from other industries and from grid-scale power applications. Adapters and bricks convert electrical energy into useable power for many types of electronic devices, including laptop computers and mobile phones. These converters are often called wall warts because they are big, bulky, and sometimes cover up an adjacent wall socket that could be used to power another electronic device. The magnetic components traditionally used to make adapters and bricks have reached their limits; they cannot be made any smaller without sacrificing performance. In this research project, we are taking a cue from grid-scale power converters that use iron alloys as magnetic cores. These low-cost alloys can handle more power than other materials, but the iron must be stacked in insulated plates to maximize energy efficiency. In order to create compact, low-profile power adapters and bricks, these stacked iron plates must be extremely thin—only hundreds of nanometers in thickness, in fact. To make plates this thin, we are using manufacturing tools used in microelectromechanics and other small-scale industries. This project is funded by the ARPA-e ADEPT program.

Laminated Metallic Magnetic Cores

Laminated Cores


  1. J. Kim, M. Kim, P. Galle, F. Herrault, R. Shafer, J.Y. Park, and M.G. Allen, "Nanolaminated permalloy core for high-flux high-frequency ultracompact power conversion," Transactions on Power Electronics,v 28, n 9, p 4376-4383, Sept. 2013. (PDF)
  2. M. Kim, F. Herrault, J. Kim, J.K. Kim, and M.G. Allen, "Monolithically-fabricated laminated inductors with electrodeposited silver windings," IEEE International Conference on Micro Electro Mechanical Systems (MEMS), p 873-876, Jan. 2013. (PDF)
  3. J. Kim, J.K. Kim, M. Kim, F. Herrault, and M.G. Allen, "Integrated toroidal inductors with nanolaminated metallic magnetic cores," PowerMEMS 2012, p 18-21, Dec. 2012. (PDF)
  4. F. Herrault, W.P. Galle, R.H. Shafer, and M.G. Allen, "Electroplating-based approaches for volumetric nanomanufacturing," Technologies for Future Micro-Nano Manufacturing, Aug. 2011. (PDF)
  5. W.P. Galle, S.-H. Kim, U. Shah, and M.G. Allen, "Micromachined capacitors based on sequential multilayer electroplating," 23nd IEEE International Conference on Micro Electro Mechanical Systems (MEMS 2010), Jan. 2010. (PDF)
  6. P. Galle, X. Wu, L. Milner, S.-H. Kim, P. Johnson, P. Smeys, P. Hopper, K. Hwang, and M.G. Allen, "Ultra-compact power conversion based on a CMOS-compatible microfabricated power inductor with minimized core losses," 57 Electronic Components and Technology Conference (ECTC '07), 2007. (PDF)
  7. J.-W. Park, F. Cros, and M.G. Allen, "Planar spiral inductors with multilayer micrometer-scale laminated cores for compact-packaging power converter applications," IEEE Transactions on Magnetics, v 40, no. 4, July 2004. (PDF)
  8. J.-W. Park, and M.G. Allen, "Ultra low-profile micromachined power Inductors with highly laminated Ni/Fe cores: Application to low-megahertz DC-DC converters," IEEE Transactions on Magnectics, vol. 39, no. 5, pp. 3184-3186, Sept. 2003. (PDF)
  9. J.W. Park, J. Park, Y.-H. Joung, and M.G. Allen, "Fabrication of high current and low profile micromachined inductor with laminated Ni/Fe core," IEEE Transactions on Components and Packaging Technologies, vol. 25, no. 1, p. 106-111, 2002. (PDF)
  10. J.-W. Park, F. Cros, and M.G. Allen, "A sacrificial layer approach to highly laminated magnetic cores," 15th IEEE International Conference on Micro Electro Mechanical Systems (MEMS), p.380-3, 2002. (PDF)