MAXREFDES1089, Miniature, 12V/250mA, Synchronous No-Opto Flyback DC-DC Converter Reference Design with 91.7% Efficiency

MAXREFDES1089, Due to its simplicity and low cost, the flyback converter is the preferred choice for low-to-medium isolated DC-DC power-conversion applications. However, the use of an optocoupler or an auxiliary winding on the flyback transformer for voltage feedback across the isolation barrier increases the number of components and design complexity. The MAX17690 eliminates the need for an optocoupler or auxiliary transformer winding and achieves ±5% output voltage regulation over line, load and temperature variations. The MAX17690 implements an innovative algorithm to accurately determine the output voltage by sensing the reflected voltage across the primary winding during the flyback time interval