Isolated Forward Converter Chipset Simplifies Designs

The LTC3765 and LTC3766 synchronous forward converter chipset features active clamp reset and Direct Flux Limit that prevents power transformer saturation under all conditions. The LTC3765 is a primary-side intelligent controller that works in concert with the LTC3766 to implement a self-starting isolated power supply. After start-up, the LTC3765 receives timing signals and bias power from the secondary-side LTC3766 controller through a tiny pulse transformer. The LTC3765/LTC3766 contains control circuitry to implement an active clamp transformer reset technique enabling efficiencies up to 96% and greater power densities when compared to conventional catch winding or resonant reset techniques. Additional features include an average current limit, fixed-frequency adjustable operation from 75 kHz to 500 kHz, clean start-up into pre-biased loads, multiphase operation for high power designs, over-temperature protection, and true remote output voltage sense. The LTC3765 is available in a thermally enhanced MSOP-16 package while the LTC3766 comes QFN-28 and SSOP-28 packages. Prices start at $1.55 and $2.60 each/1,000, respectively. LINEAR TECHNOLOGY CORP., Milpitas, CA. (800) 454-6327.