This paper presents development of the rotational electromagnetic energy harvesting transducer. The transducer is driven mechanically by pushing a button; therefore, the mechanical energy will be converted into electrical energy. The energy harvesting (EH) transducer consists of multilayer planar coils embedded in a PCB, multipolar NdFeB hard magnets, and a mechanical system for movement conversion. The EH transducer generate an energy of about 4mJ at a load of 10Ω. The maximum open circuit output voltage is as high as 2V and the maximum short circuit output current is 800mA

This paper describes the development of an inductive microposition measuring system based on the "Inductosyn" principle and its fabrication using thin-film technology. By integrating a soft magnetic flux guide, the coupling between excitation and sensing coils was increased. The system consists of two principle components: a stationary planar meander coil and two planar meander coils positioned on a slider. The sensor device was simulated by applying the finite-element method. Thin-film processes were used to fabricate an inductive microposition measuring system. Initial measurements show an induced voltage of 9 mV at an excitation current of 40 mA and a frequency of 5 MHz

This paper presents a miniaturized and cost effective power management system (PMS) for low-voltage electromagnetic energy harvesters (EMEHs) operating in both battery powered and batteryless applications. The PMS consists of two converters and their associated controllers. The first converter converts EMEH’s ac voltage into a dc one in a single step and provides a maximum efficiency point tracking (MEPT) feature to maximize the harvested energy and can be used alone in battery powered applications. The second converter provides tight output voltage regulation for batteryless applications. The MEPT converter utilizes a topology that uses a single inductor shared between positive and negative half cycles of the EMEH voltage, unlike the majority of existing solutions, and hence achieving system’s cost and size reductions. In addition, its control architecture is based on low power comparators and does not require zero crossing detection (ZCD) block, in contrast to many existing solutions, allowing for further reduction in cost, losses, and size. Moreover, the shared inductor is not only used by the power stage but also as a key element of the bias supply scheme allowing for voltage stepping up and hence providing sufficient voltage to supply the control circuits. The voltage regulation converter features a highly integrated dc-dc converter where the power inductor serves as normal inductor and a substrate for the converter. Experimental results show the effectiveness of the PMS with an EMEH that has a damped ac voltage characteristics ranging from 1.0V to 10mV for battery and batteryless applications. The presented MEPT converter, switching at 40KHz, achieves 32.3 mm3 magnetics volume, which is the biggest contributor to the real estate of the PMS. Also, it can harvest up to 17mJ out of 20mJ available energy while achieving a BOM cost less than 0.7€. Moreover, the highly integrated buck converter, switching at 4MHz, provides a tight regulated voltage of 1.2V at 5mA for a group of wireless sensors while achieving efficiency of 80% for load currents between 100μA and 200mA.

This paper presents the design, fabrication, and characterization of on silicon integrated magnetics for high frequency power applications. The presented device achieves superior characteristics in terms of energy density, electrical resistance, current capability, and inductance vs frequency stability. In order to demonstrate the effectiveness of use of the presented device for high frequency power applications, it is tested with two different buck point of load (PoL) dc-dc converters, one of them is off-shelf chipset and the other is designed specifically for the microdevice. Experimental measurements show that the microdevices achieve a maximum inductance of about 50nH, electrical resistance of 300mΩ, rated current capabilities up to 1A, and stable L vs f characteristics up to 100MHz. Also, the PoL buck converters with the microdevices achieve a peak efficiency of up to 82% with a flat efficiency curve at switching frequencies up to 30MHz while providing tight output voltage regulation (<0.2%) and low temperature rise (40°C) at the rated current.

This work presents the development of a dual-rotor rotational electromagnetic energy harvesting (EH) generator and its power management system (PMS). The electromagnetic harvester is driven mechanically by pushing or pulling a shaft. By doing so, energy can be harvested in both directions. The PMS steps up the AC voltage of the EH and converts it into a useful DC one utilizing a maximum power point tracking (MPPT) concept. The PMS together with EH are tested and experimental results for the full system are presented. The EH device generates a maximum output energy of 100 μJ with a maximum open circuit voltage of 0.7 V. The PMS achieves an efficiency of 70% while providing 350 μA at its output.

This paper presents a development of a microtransformer device fabricated using MEMS technology. The device is designed for higher switching frequencies beyond to 50 MHz power applications. The microtransformer features a closed magnetic core and six identity coils (three coils on primary and three coils on secondary side). Depending on connecting technique, this design allows a wide flexibility to set different values of inductance and of transformer winding ratio. As a magnetic core material Fe-Co alloy is applied, this device shows a significant improvement compared to the first fabricated prototypes with Ni-Fe magnetic core.