by Dennis Feucht, Innovatia Laboratories, Cayo, Belize, How2Power Today, Oct 17 2019
Focus:
One of the goals of magnetics design is to achieve the greatest utilization possible from a
magnetic component. Utilization, U, is defined quantitatively based on waveforms, as the
average value of current (or voltage) divided by the peak value of current (or voltage). U
expresses the extent to which a component is able to deliver the desired quantity, the
average, relative to the maximum of that quantity that it must handle, or the peak rating.
The extent to which the ideal value U = 1 can be achieved depends on the circuit. This
article examines four popular isolated power supply topologies—the flyback, forward, full
bridge and half bridge converters—to see the impact each has on utilization of the
transformer. A study of the current flows and their duty ratios explains why transformer
utilization is higher or lower in certain topologies. The costs of achieving the higher
utilization (additional power switches and capacitors) and other design tradeoffs are
discussed.
What you’ll learn:
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