Fairchild Semiconductor Power Seminar 2007/2008

Abstract — Recently the, LLC resonant converter has drawn a lot of attention due to its advantages over the conventional series resonant converter and parallel resonant converter; narrow frequency variation over wide load and input variation and Zero Voltage Switching (ZVS) of the switches for entire load range. This topic will discuss the analysis and practical design considerations of a LLC-type resonant converter. Included in this discussion will be the design of a transformer and the selection of components, a step-by-step design procedure, and a design example that will help engineers design the LLC resonant converter easily.

coming soon

Abstract — Learn “how to” design an isolated constant current source to drive high power LED’s from an AC power line. The constant current source is built using a flyback topology and has an efficiency greater than 80%. Conventional current sources need many components for this. This application is a low-cost solution based on an innovative circuit (patent filed) using a Fairchild Power Switch (FPS). The converter is a primary side regulated removing the need for an optocoupler and other additional components.

Abstract — Power MOSFETs require a gate drive circuit to translate the on/off signals from an analog or digital controller into the power signals necessary to control the MOSFET. This topic provides details of MOSFET switching action in applications with clamped inductive load, when used as a synchronous rectifier, and driving pulse/gate drive transformers. Potential driver solutions including discrete and integrated driver designs are discussed. MOSFET driver datasheet current ratings are examined and circuits are presented to assist users in evaluating the performance of drivers on the lab bench.

Abstract — Half-bridge structures are extensively used in power electronics applications: lighting, power supplies, UPS and motor drives. When these half-bridge circuits are hard switched, the low side diode reverse recovery affects system performance. This topic reviews the principle of diode reverse recovery and how this affects the semiconductor switch performance. Practical tests showing how di/dt and temperature affect performance are presented. Finally measurements using different devices are compared showing the curves for fast and soft recovery diodes, showing that in some cases, efficiency can be improved by adding capacitance in parallel with the diode.

Abstract — Circuit simulation tools are useful supplements to breadboarding for gaining fast and detailed design insight. A collection of simulation tips and tricks used by Fairchild’s Global Power Resource support group is presented. Interactive on-line design simulation tools and device models for off-line solutions are available on the Fairchild website.