Martin Haug

On-chip high performance magnetics for point-of-load high-frequency DC-DC converters

This paper presents the design, fabrication, and characterization of on silicon integrated micro-transformers for high frequency power applications. The microtransformer device is used and tested in DC-DC converter application at high switching frequency. This device has stable L vs. f characteristic up to 50 MHz. The design is improved regarding to the electrical resistance and current capability. The microtransformer shows an inductivity of about 60 nH, resistance of 350 mΩ and can be applied for current up to 1.5 A.

Portable rotational electromagnetic energy harvester with a maximum energy tracking power management system

This paper presents a development and fabrication of a rotational electromagnetic energy harvesting (EH) system. The electromagnetic harvester is driven mechanically by pushing a button. The energy harvester converts the linear translation of the button into rotation with a rotational speed of about 1000r/min. The electromagnetic part of the harvester consists of a multilayer planar coils embedded into PCB and of multipole NdFeB permanent magnets. The energy harvester device generates maximal energy of about 20mJ. The maximal open circuit voltage up to 4V is achieved. Also, the Power Management System (PMS) used with the EH is discussed and shown. The PMS is based on a dual phase buck-boost topology that converts ac-to-dc voltage in a single stage. Moreover, the PMS combines a maximum energy tracking feature, based on resistive impedance tracking, without adding additional components. Experimental results show the ability of the PMS to convert from ac-to-dc voltage while providing a maximum energy tracking feature.