Tuesday, September 14, 2010Orlando, Florida

Wednesday, September 15, 2010Dallas, Texas

Tuesday, September 21, 2010Boston, Massachusetts

Wednesday, September 22, 2010Toronto, Canada

Tuesday, September 28, 2010San Jose, California

Thursday, September 30, 2010Vancouver, Canada

Tuesday, October 5, 2010Phoenix, Arizona

Wednesday, October 6, 2010Santa Ana, CA

Tuesday, October 12, 2010Chicago, Illinois

Wednesday, October 13, 2010Milwaukee, Wisconsin

Thursday, October 14, 2010Minneapolis, Minnesota

Tuesday, October 19, 2010Sao Paulo, Brazil

Thursday, October 21, 2010Porto Alegre, Brazil

Thursday, October 28, 2010Taipei, Taiwan

Wednesday, November 10, 2010Shanghai, China

Friday, November 12, 2010Beijing, China

Monday, November 15, 2010Shenzhen, China

Abstract - This article explains the principles of AC-DC converters in flyback topologies having a high power factor input and a constant current output. The most commonly used mode of operation for this purpose is boundary conduction mode (BCM). This paper explores the fundamentals of this mode of operation and the potential drawbacks of each. It also explains a simple method for improving power factor. Furthermore, it describes in detail how operating in discontinuous conduction mode (DCM) improves power factor and thermal harmonic distortion (THD) while reducing the peak drain voltage. This result is illustrated through a design example. The paper also delves into the special issues a designer encounters when driving high power LEDs.

Abstract - The objective of this paper is to describe the driving methods and layout requirements for fast switching MOSFETs. Power MOSFET technology continues to evolve towards higher cell density for lower on-resistance. However, there are silicon limits for a significant reduction in the on-resistance with the conventional planar MOSFET technology due to the exponential increase in on-resistance with increasing breakdown voltage. One approach to overcome this limitation is to use Super-Junction technology in high voltage power MOSFETs. This technology dramatically reduces both on-resistance and parasitic capacitances. With smaller parasitic capacitances, these Super-Junction MOSFETs have extremely fast switching characteristics and as a result, reduced switching losses. This switching behavior occurs with greater dv/dt and di/dt that affects switching performance through parasitic components in the devices and on the printed circuit board and influences the EMI performance of the entire system. An optimized design is very important to operate high speed MOSFETs.

Abstract - Increasing power density, faster switching and higher currents forces designers to spend more time both considering the effects of electromagnetic interference (EMI) and debugging a design that has EMI problems but is otherwise complete. This paper explains the different types of EMI and their coupling mechanisms and the existing EMI regulations. The most frequent noise sources, transmission paths and receiver sensitivity are examined. Based on real designs and measurements, specific procedures are recommended for use throughout the design cycle, to make the power supply work reliably and pass EMI testing.

Abstract - The environmental impact of energy consumed by electrical appliances when not in use has attracted growing attention in the international community. This paper discusses how the selection of passive components in switched-mode power supplies (SMPSs) affects standby power consumption. Based on analysis, this paper presents how to select passive components to minimize the standby power consumption of SMPSs. The validity of the proposed selection guideline is verified with a 50W prototype power supply.

Abstract - Negative feedback control is used in switched-mode power supplies to regulate the output at a desired value. The optimum design of the feedback control loop starts with understanding the characteristics of the power stage, which can be analyzed using small-signal modeling. This paper explains the fundamental idea and meaning of small-signal modeling for power supplies and explores the small-signal transfer functions for basic converters and general compensation networks. It also discusses the practical issues with feedback loop design, including characteristics of the optocoupler, effects of parasitic components, multiple output applications, and loop-gain measurement.

Abstract – Coming Soon…