High-Density, High Efficiency, Card Mounted Low Voltage Power Supply

Obtaining a low voltage board mounted power module that can achieve an acceptable power volume/weight density and overall conversion efficiency while meeting power quality requirements will require application of several new promising technologies. These includes: (1) high frequency, soft-switching PWM converter topologies, (2) synchronous rectifiers, (3) low profile magnetic structures, (4) thick film hybrid packaging techniques. A recently developed ZVS PWM forward converter with an active clamp combines the soft switching advantages of a resonant converter with the low voltage and current stress of a PWM converter. The converter also allows self-driven synchronous rectifiers. Obtaining the necessary power density and efficiency will also require an advanced magnetics design with possibly PCB or printed windings. Internal wiring must held to a minimum with transistor and diode dies are mounded directly on the transformer windings. The problem cannot be solved without advanced computer-aided design tools such as finite-element analysis and thermal analysis software. The goal is to achieve a power density of 100W/in(cubed) and an efficiency of 90%.