Inherent benefits of a 1 MHz high precision mag amp regulated off-line switching power supply

This paper will describe a method for meeting a tight multiple output switching power supply specification. Although there aTe many excellent supplies available, cost usually dictates a performance tradeoff for the outputs that are not main loop regulated. The proposed technique uses a feedforward compensated 1 MHz power stage followed by individual secondary mag amp regulators. A Unitrode UCI825 high frequency pulse width modu lator contro Is all primary side functions (See Fig. I).