S.C. O'Mathuna

Electrical performance of microtransformers for DC-DC converter applications

This paper presents the electrical performances of the fabricated microtransformers. Measurements for open-circuit and short-circuit impedance up to a frequency of 100 MHz are presented. The measured results are compared with predictions obtained from models based on an analytical approach. The use of a microtransformer in a 2-MHz dc-dc converter is reported. An efficiency of 40% for a power density of 1.2 W/cm/sup 2/ was measured.

The development of a novel minaturized modular platform for wireless sensor networks

Wireless sensor networks are collections of autonomous devices with computational, sensing and wireless communication capabilities. Research in this area has been growing in the past few years given the wide range of applications that can benefit from such a technology. In this paper, the development of a highly modular and miniaturized wireless platform for sensor networks is described. The system incorporates a radio transceiver (in the 2.4 GHz ISM Band) with embedded protocol software to minimize power consumption and maximize data throughput. Additional input capability for sensor and actuator integration can be incorporated seamlessly due to the modular nature of the system. The total system is packaged in a modular 25 mm cubed form factor. A smaller, (10 mm cubed), prototype is currently under development. Ongoing development of highly miniaturized nodes is discussed.

Power Electronics Enabling Efficient Energy Usage: Energy Savings Potential and Technological Challenges

Power electronics is a key technology for the efficient conversion, control, and conditioning of electric energy from the source to the load. In this paper, the potential of power electronics for energy savings in four major application fields, buildings and lighting, power supplies, smart electricity grid, and industrial drives, is investigated. It is shown that by wider adoption of power electronics in these areas, the current European Union electricity consumption could be reduced by 25%. The technology challenges for exploiting this potential for all the four areas are identified in the paper.

Thin-Film-Integrated Power Inductor on Si and Its Performance in an 8-MHz Buck Converter

This paper presents a microinductor fabricated on silicon using electrochemical techniques that has high efficiency in a low power dc-dc converter. Small signal measurements show a flat frequency response up to 20 MHz with a self resonant frequency of 130 MHz. The inductance at low frequency is approximately 440 nH with a dc resistance of 0.5 Omega , and a high quality factor of 11.7 at 5.5 MHz. The current handling capability test shows less than 10% decrease in inductance at 500-mA current. The performance of the microinductor has been compared to a conventional chip inductor in a commercially available 8-MHz buck converter. The converter maximum efficiency when using the microinductor is shown to be approximately 3% lower than the one using the conventional discrete chip inductor. However, the profile of the microinductor is much lower than that of the discrete chip inductor. The maximum efficiency of the microinductor in the converter is estimated to be approximately 92%.

Size and Performance Tradeoffs in Micro-Inductors for High Frequency DC-DC Conversion

This paper presents the design and measurement of optimized inductors-on-silicon (ldquomicro-inductorsrdquo) for use in high frequency DC-DC conversion applications. These ultra-compact low profile (< 70 mum) inductors range in area from 0.5-2.5 mm² . The design process utilizes optimization software that finds the optimal physical dimensions, to maximize inductor efficiency, given certain technology constraints. Optimized micro-inductors achieve measured inductance densities of 66 nH/mm² for a 2.5 mm² area, 110 nH/mm² for 1.3 mm² device and 82 nH/mm² for a 0.5 mm² footprint area. Measured saturation currents range from 0.15-0.5 A for the optimized devices.

Design, Fabrication and Testing of Miniaturised Wireless Inertial Measurement Units (IMU)

This paper will describe the design, fabrication, operation, and test results of a miniature wireless inertial measurement unit (WIMU) with a form factor of 10 mm. Many types of Inertial Measurement Units(IMU) have been designed and manufactured by prominent companies such as Crossbow, Xsens, O NAVI and Honeywell, among many others. American GNC Corporation currently claims to have the worlds smallest IMU[1]. Most of these IMUs are aimed at aerospace and other types of navigation, which is why miniaturisation has not been a priority. However, with the onset and development of MEMS technology, novel applications have been found for those MEMS sensors employed in an IMU. Head mounted displays, Segways and mobile phones are among the new products taking advantage of miniaturised MEMS inertial sensors. The current WIMU development is a step along the roadmap of the AES team at Tyndall National Institute towards miniaturisation and works from the current standard, the 25 mm platform [2]. A 25 mm stacked SMT IMU has been successfully developed and tested [3,4]. The goal now is to develop an even smaller version of this IMU by using advanced technology such as flexible substrates and flip-chip technique. These miniaturised IMUs are required for wearable and medical applications where size and weight are priorities. Our WIMU uses bare-die versions of off-the-shelf MEMS sensors. The Inertial Measurement Unit itself is designed to give full six degrees of freedom with 3-axis for each of the sensors-accelerometers, gyroscopes and magnetometers.

Design study for ultra-flat, PCB integrated inductors for low power conversion applications

In this paper the effectiveness of integrated cores is investigated as a function of various core parameters. This is a step towards optimised magnetic structures for this novel type of component.

Magnetic-Core and Air-Core Inductors on Silicon: A Performance Comparison up to 100 MHz

What is the future of integrated inductor design on silicon for power conversion applications at frequencies up to 100 MHz-is it magnetic-core or air-core inductors. This study presents measured results for two microfabricated inductors (magnetic core and air core), which have been designed to operate at 20 MHz and occupy a substrate area of less than 10 mm2. The inductor technology and design are briefly discussed. An optimized inductor design study is, then, presented. Both magnetic-core and air-core inductor designs are compared and evaluated, in terms of inductance and efficiency per unit area for frequencies up to 100 MHz. The design of the microinductors is discussed and an analytical design optimization program is used to model the devices for the maximum efficiency and inductance. The introduction of laminations with high-frequency core inductors will also be examined within the study. A 100 MHz magnetic-core inductor design with three laminations gives a 36 nH inductance, with 96.4% efficiency and an area of 3 mm2 . A comparable air-core design also gives a 36 nH inductance, with 93.45% efficiency and an area of just 2.6 mm2.

Technology roadmapping for Power Supply in Package (PSiP) and Power Supply on Chip (PwrSoC)

This paper presents a review and summary of the PSMA ¿PSiP2PwrSoC¿ Special Project that investigated the technology and performance underpinning recent commercial developments in Power Supply in Package and Power Supply on Chip. The results of the study are based on the identification of more than 28 commercial products, 6 of which were analyzed in detail, both physically and electrically. The methodology of the project is described and some of the salient results of this benchmarking effort are presented. In this work, a representative subset of the available commercial products was selected and a comprehensive physical, electrical and thermal performance analysis was carried out. The main aims of this analysis were to identify the components, materials and assembly technologies used, and to determine if the drive towards greater integration and higher power density affected the performance of newer devices. The results of the analysis were then used to determine the current state of the technology in this application space, to show how it has developed to date and to predict how it might progress in the future. These results are presented in a generic format that does not identify individual products. This project was co-sponsored by the PSMA and member companies. The final report of the project, which includes more detailed information on the reviews described here as well as considerable trending analysis, is now available.

A wireless inertial measurement system (WIMS) for an interactive dance environment

This paper will present the work carried out in designing a Wireless Inertial Measurement System (WIMS) designed for a wearable system operating in an interactive dance environment. The concept underpinning this system is the generation of inertial information from multiple nodes distributed over a dancers body, which will enable the dancer to communicate with their environment and interact with their surroundings through movement. The IMU nodes will be arranged in a network configuration whose control will be based upon existing technology developed at Tyndall.