Switching regulators are commonly used to step-down a higher level, " unregulated input voltage to a regulated output voltage. In applications requiring DC-DC conversion from a relatively high input voltage, a switching regulator will dramatically improve conversion efficiency relative to linear regulator alternatives. Two of the most common transformer based DC-DC converter topologies are the Flyback and Forward. These topologies are very effective for high input to output step-down ratios since the transformer turns ratio can be set to accomplish the majority of the step-down conversion. For example, the conversion equation for a Forward converter is approximately: V_(OUT) = V_(IN) X D X Ns/NprnWhere D is the duty cycle of the modulating switch, and Ns and Np are the quantities of the transformer secondary and primary turns.
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