A novel 12 kW switch mode power supply

A new 200 A switch mode power supply (SMPS) for telecommunications applications was developed. The authors detail the most significant electrical characteristics of the SMPS. The power transfer mechanism is based on a full bridge PWM configuration. The basic switching device chosen was the power MOSFET. This semiconductor is packaged by various companies in isolated modules containing four parallel dies. The unit uses two of these modules in parallel as one switch so that a total of eight modules are utilized. FETS were chosen over other devices because of their low drive requirements, speed, and their sharing characteristics when operating in parallel. The stray capacitances associated with high power switching devices, in conjunction with the use of saturable beads, provide for some desirable inherent snubbing effect. A description is given of power transformer design, power factor correction, and of some precautions in designing for optimally low EMI emission and the highest lightning surge protection.<>