Offline PFC Regulator Needs No Opto

The LT3798 isolated flyback controller with single stage active power factor correction (PFC) achieves a power factor greater than 0.97 by actively modulating the input current. This eliminates the need for an extra switching power stage. Also, no opto-isolator or signal transformer is required for feedback since the output voltage is sensed from the primary-side flyback signal. Efficiencies greater than 86% are possible with output power levels up to 100W. The device’s input voltage range is dependent on the choice of external components and it can operate over a 90 to 277 Vac range, scalable higher or lower. Available in a thermally enhanced 16-pin MSOP, pricing starts at $2.25 each/1,000. LINEAR TECHNOLOGY CORP., Milpitas, CA. (800) 454-6327.