Linear Tech Isolated Power Factor Corrected Offline Regulator Needs No Opto

Linear Technology Corp. announced the LT3798, an isolated flyback controller with single stage active power factor correction (PFC). A power factor of greater than 0.97 is accomplished by actively modulating the input current, eliminating the need for an extra switching power stage and associated components. In addition, no opto-isolator or signal transformer is required for feedback since the output voltage is sensed from the primary-side flyback signal.

A LT3798-based design easily complies with the IEC61000-3-2 Harmonic Current Emissions specification. Efficiencies greater than 86% can be achieved 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 277Vac range, and can easily be scaled higher or lower.

Furthermore, the LT3798 can be designed into high input voltage dc applications, making it well suited for industrial, EV/EHV automotive, mining and medical applications. The LT3798 utilizes critical conduction mode operation, enabling the use of a smaller transformer compared to continuous conduction mode designs, further reducing the solution size.

The LT3798 is available in a thermally enhanced 16-pin MSOP package. The LT3798E and LT3798I versions operate from -40 to 125°C. The LT3798H is tested and guaranteed to operate from a -40 to 150°C operating junction temperature. 1,000-piece pricing starts at $2.25 each.

More news and information regarding the latest developments in Smart Grid electronics can be found at Darnell’s SmartGridElectronics.Net.