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The electronic circuit breaker used in DC microgrids are required to work within their safe operating areas bounded by temperature, voltage and current limits. Traditional approach managed to protect these switches through rapid current cut-off operations at over-load or fault situations, but failing to avoid the disturbance induced by transient current surges or noises which are not harmful to the grid operations. Aiming to increase the quality of circuit breaker operations and furthermore improve its reliability, this paper proposed a SiC MOSFET based DC circuit breaker based on the variable time-delay protection scheme. The cutoff operations only take place after proper delay time, which are precisely catered according to the transient thermal properties of SiC devices and the properties of DC loads. The proposed scheme has been implemented with hardware prototype and experimentally verified under different fault situations.

The superjunction MOSFET power devices, such as p-n column superjunction (named SJ or CoolMOS) devices and oxide-bypassed (OB) devices, are highly recognized for their higher blocking capability and lower on-state resistance. However, the performance of SJ devices is greatly handicapped due to difficulties in formation of perfect charge-balanced SJ p-n columns by the current process technology, especially for devices with small widths and voltage ratings below 180 V. OB devices can be an alternative in this voltage region, which utilize the well established oxide thickness control in fabrication instead of the difficult doping control as in SJ devices. However, OB drift region electric field distribution is not as optimal as that in SJ devices. Gradient oxide-bypassed (GOB) structure enhances the performance of OB devices so that it can achieve a performance comparable to that of an ideal p-n column SJ device in the medium voltage range, and at the same time, requires simple process technology. Complete descriptions on the GOB device and related design issues are presented in this paper. Fabrication issues are also discussed with possible sacrificial materials and etchants for making the vertical graded oxide sidewalls. Design cases for 80, 120, and 180 V GOB devices are also illustrated for better understanding in the device. Index Terms--Breakdown voltage, gradient oxide-bypassed (GOB), ideal unipolar silicon limit, oxide-bypassed (OB), power MOSFETs, specific on-state resistance, superjunction.

This paper describes research work on the design and fabrication of current sensor suitable for smart power integration in lateral insulated-gate bipolar transistor (LIGBT) structure. In general, the proposed design can also be used for various types of MOS- controlled bipolar transistor structures. Both the electron and hole current sensor layers are integrated in a concise form within the device structure. The sensing performance was further refined with the proposed flat-top doping profile achievable through a double-implantation, single-anneal and post-anneal-oxidation approach. The integrated structure was fabricated on silicon wafer with laboratory measurements performed to verify its electrical performance. The sensing ratio is maintained at a relatively constant level with a variation of within [+ or -] 0.46% and [+ or -] 1.2% (as a switching device), and [+ or -] 0.85% and [+ or -] 1.73% (as an amplifier device), respectively, when anode current and gate voltage vary. For operating temperature range of 300 K to 400 K, the sensor is able to maintain a sensing ratio within [+ or -] 5.2% variation. Index Terms--IGBT, integrated current sensor, smart power integration.

A new partial silicon-on-insulator (SOI) formation technology and the associated RF LDMOSFET device structure on silicon bulk substrate are described. The technology assists in the reduction of drain/substrate parasitics and leakage current for devices fabricated on bulk substrate.

A new silicon RF vertical double-diffusion metal-oxide semiconductor field-effect transistor (VDMOSFET) structure is proposed, which includes a dummy gate between the device's active gates. The dummy gate acts as a field plate, minimizing drain-to-gate feedback capacitance and raising its breakdown voltage.

In low-output-voltage dc/dc converters, power losses due to the conduction of rectifying devices are significant. Using synchronous rectifiers instead of the conventional fast recovery diodes or Schottky diodes is an effective solution to this problem in most topologies. However, for synchronous rectifiers to perform effectively, it requires an external gate drive with proper sensing and timing control circuits. This can increase the complexity and cost in converter hardware implementation. For the first time, a smart power synchronous rectifier (SPSR), which is a two-terminal MOS rectifier, is designed to overcome this difficulty. The SPSR integrates a simple control unit with a power MOSFET into a smart module to form a self-controlled synchronous rectifier. It has great advantages over the conventional discrete circuit composition, such as integrated gate control, precise timing switching, and fast transient response, which are suitable for applications in high-frequency pulsewidth modulation (PWM) converter circuits. Index Terms - Power electronic devices, synchronous rectification.

Based on a generalized state-space sampled data modeling, an iterative and efficient algorithm for deriving the small signal transfer functions of any dc-dc converter is proposed. This algorithm is suitable to be implemented in a software program as an analytical tool for automated control analysis of general dc-dc converters. Such a tool would reduce considerably the time needed by research engineers in modeling existing and new topologies and control methods. The algorithm proposed is applicable to different kinds of linear and nonlinear control methods. It has been verified on different converters and control methods.

Three-dimensional (3D) high-temperature Hall sensors are strongly required in various applications such as in the automotive and aircraft engines and in the diagnostic system of the thermonuclear reactors. In this paper, we propose a novel Hall sensor based on the wide-bandgap GaN-based materials on a single chip with greatly reduced area which can simultaneously detect 3D magnetic fields at high temperature up to 650 K. The device is analysed and demonstrated by performing the technology computer-aided design simulations, and significantly improved performances are achieved by employing space isolation and passivation scheme to effectively reduce the carrier interference from each dimension. Finally, high current-related magnetic sensitivities are found and the typical values are 128.6, 88.1, and 49.9 V A−1 T−1 on x, y and z axes, respectively, at room temperature. And the temperature coefficients are as low as −286.4, −366.8, and −202.9 ppm K−1, respectively. Moreover, dramatically improved cross-sensitivities are revealed and the maximum value is less than 1.0% at B ≤ 1.0 T which is much lower compared with other currently reported data. The work provides a new technical approach to realize a single-chip 3D magnetic sensor which is promising especially for high-temperature applications. [ABSTRACT FROM AUTHOR]

In this paper, a new actuation scheme for the push-pull electrostatic microelectromechanical systems comb drive actuators is proposed. The displacement amplitude excited by the new form of driving voltages can be more than three times as large as that which is achievable using the conventional form for the same applied system voltage. Index Terms--Microactuation, microelectromechanical systems (MEMS) comb drive.

An integrated current sensor for the lateral insulated-gate bipolar transistor power devices was developed. Both the hole and electron current were independently sensed at the same proportion to maintain a constant current sensing ratio. This gives a constant sensing ratio of 1.04 mA/A, and the sensor also maintains a constant ratio during transient turn-off. However, a small variation of the sensing ratio is observed over certain temperature range.