Isolated Active PFC Off-Line LED Controller Is TRIAC Dimmable & Needs No OPTO Isolator

Feb 7 2011 - MILPITAS, CA
  • Linear Technology announces the LT3799, an isolated LED controller with active power factor correction (PFC), specifically designed for driving LEDs from a universal input range of 90VAC to 265VAC. The LT3799 is optimized for LED applications requiring 4W to over 100W of LED power and also compatible with standard TRIAC in-wall dimmers. The LT3799's unique current sensing scheme delivers a well regulated current to the secondary side without using an opto-coupler. This not only reduces cost but also improves reliability. Its single stage PFC regulator design requires minimal external components. Additionally, its thermally enhanced MSOP-16E package ensures a simple and compact solution footprint for off-line LED applications.

    The LT3799 offers over 86% efficiency, eliminating the need for external heat sinking of the LED driver IC in most applications. Special internal circuitry provides active PFC of up to 0.977, easily meeting industrial Department of Energy (DOE) requirements while also complying with the IEC 61000-3-2 Class C Lighting Equipment Harmonics requirement. The LT3799 can be used with a standard in-wall TRIAC dimmer without any visible flicker. Open and shorted LED protection ensures long-term reliability for a wide range of LED applications.


    The LT3799EMSE is available in a thermally enhanced 16-pin MSOP package. Pricing starts at $2.25 each in 1,000‑piece quantities and is available from stock. An extended temperature version, or "I" grade, the LT3799IMSE is also available from stock, priced starting at $2.59 each in 1,000‑piece quantities. For more information, visit

    Summary of Features: LT3799

    • Isolated PFC LED Driver with Minimum Number of External Components
    • VIN and VOUT Limited Only by External Components
    • Works with Standard TRIAC dimmers
    • Active Power Factor Correction
    • Low Harmonic Content
    • No Opto-Coupler Required
    • Accurate (±5%) Regulated LED Current
    • Open & Shorted LED Circuit Protection
    • Thermally Enhanced 16-Lead MSOP Package

    Isolated Active PFC Off-Line LED Controller

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