The UCG28826 supports min. 2x transient peak output power capability for applications which require bursts of high power for short durations of time. This is achieved without the need for oversizing the various components such as the transformer, power FETs etc. and the same flyback design is usable for min. 2x the continuous output power rating for short durations. With this, a 65W flyback converter designed with UCG28826 can deliver min. 130W transient peak output power for max. 80 ms duration during high line and 4ms during low line operating conditions.

At high line input, the transient peak power delivery happens in DCM/QR modes of operation and is limited to max. 80ms duration as per OPPH protection described in Section 6.4.10.4. At low line input, due to limitations in power delivery from DCM/QR modes, the continuous conduction mode (CCM) extends the operation to min. 2x of the nominal power rating, and limited to max. 4ms duration. To limit from large output power delivery at high line input, the CCM mode is disabled for input bulk capacitor voltage higher than 200V DC. Further, CCM mode of operation at low line input (<200V DC) is limited to 4ms max. and device returns to 1st valley QR mode of operation if the transient output load does not reduce by the time of expiration of this 4ms timer. The CCM mode of operation is described in Section 6.4.2.4. Peak power delivery in DCM/QR modes at higher than 140W for longer than 80ms triggers OPPH fault, as detailed in Section 6.4.10.4. A min. 2x transient output power is supported, while max. instantaneous transient output power in DCM/QR/CCM modes depends on the input bulk capacitor voltage and the power stage component values and is limited in time by the respective CCM, OPPH, and OPPL timers.