Point-of-load (POL) power supplies contribute significantly to the overall volume, weight, and cost of many electronic devices. This is mainly due to the fairly large inductor of the buck converter commonly used in these applications, which causes it to have a relatively low power density. The goal of this paper is to propose an alternative converter for POL applications which uses a much smaller inductor. The proposed converter, referred to as a transformerless dual active half-bridge (DAHB), uses an ac-link to transfer power, instead of the more conventional dc-link. Not only does the transformerless DAHB offer a significant reduction in the volume of the bulky inductor, but it also allows soft switching and 50% duty cycle operation of all active devices. The advantages of the proposed converter have been verified with a 12 V to 3.3 V, 10 A, 0.3 MHz to 1 MHz experimental prototype. The results demonstrate a reduction of approximately 50% in the volume of reactive components, while maintaining high power processing efficiency.

This paper presents a novel step-up power converter architecture for portable applications with multicell battery packs that integrates battery cell balancing function. Compared to conventionally used boost converter, which is not providing cell balancing, the new architecture has smaller overall volume and approximately the same power processing efficiency. The step-up function is obtained using the assisting concept, where the flyback output is placed at the top of the battery pack and, therefore, is only processing a portion of the output power. As a result, high-power processing efficiency and small converter volume are achieved. The operation of the system is regulated by a digital controller that provides the two functions at the same time. Experimental results obtained with an 8-to-12 V, 20 W, 500 kHz prototype demonstrates that the assisting flyback simultaneously provide output voltage regulation and cell balancing. Operation of the converter during charging and discharging is demonstrated. Also, a conventional boost converter that has the same input–output specifications is built and tested for comparison. The results show that, compared to the equivalent boost which is the most commonly used converter in the targeted applications, the prototype has about 23% smaller overall volume and a comparable power processing efficiency curve with a peak efficiency of a 93.4%.

In this paper, we are reporting the design, fabrication and characterization of on-chip solenoid inductors with novel magnetic thin-film core for high frequency DC-DC power conversion application. Our CMOS - BEOL process compatible micro-inductor fabricated shows a high L/Rdc up to 440 nH/Q due to a thick Cu winding, as well as a high inductance density of 440 nH/mm ² and high Q factor of 14.5 at 10 MHz which results from inclusion of laminated Co-based magnetic core which is amorphous and shows very good soft magnetic properties. The on-chip magnetic-film inductor technology is targeted at applications that enable high frequency (>10 MHz) DC-DC power conversion.

This paper presents a high power density battery management system for electromobility applications that integrates voltage step-up and cell balancing functions inside a single converter topology. The presented system is based on assisting conversion concept, implemented with multiple dual active bridge (DAB) converter modules. The assisting conversion, where the converter is only processing a portion of the output power proportional to the voltage difference between the battery pack and the output of the converter, allows for the use of a smaller converter than those of conventional systems. Also, at the system level, this type of conversion results in a higher power processing efficiency. The modular structure of the converter provides multiple connections to battery cells and allows on-line cell balancing during standstill, charging, and discharging of the battery pack. The operation of the system is regulated by a practical digital controller that performs cell balancing and, at the same time, regulates the output voltage. Experimental results obtained with a 24-to-48V, 200W, 100 KHz converter for small scooters demonstrate that the assisting converter is capable of providing the two previously mentioned functions while having a smaller volume and better power processing efficiency than both the conventional DAB and boost based solutions. The assisting DAB converter runs at a peak efficiency of a 95.4% and processes only a maximum of a 66% of the output power.

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.