New start-up schemes for isolated full-bridge boost converters

Two new start-up schemes for isolated full-bridge boost converters are proposed in this paper. The control timing for each scheme, which is compatible with pulse-width modulated (PWM) control timing for normal boost mode operation, are investigated. Design considerations on the relationship between the turns ratios of the boost choke windings and the main transformer windings, and its effects on the operation of the converter, are studied. The two proposed start-up schemes are experimentally verified on a 1.6 kW, 12 V/288 V prototype.