December 12, 2011 – Linear Technology Corporation (Country Manager: Hong Sa-kwak) announced the development of an isolated flyback controller (product name: LT3798) equipped with single-stage active power factor correction (PFC). This product can achieve a power factor of 0.97 or higher by actively modulating the input current, eliminating the need for additional switching power stages or related components. Furthermore, since the output voltage is sensed from the primary flyback signal, it is characterized by the fact that no opto-isolator or signal converter is required for feedback.
Designing with the LT3798 easily meets IEC61000-3-2 harmonic current emission specifications. It is possible to achieve efficiencies of over 86% at output power levels up to 100W. While the input voltage range depends on the selection of external components, it operates within the 90VAC to 277VAC range and can be adjusted higher or lower. The LT3798 is suitable for high-input voltage DC applications, making it ideal for industrial, EV/EHV, mining, and medical applications. A key advantage of the LT3798 is its critical conduction mode operation, which enables the use of smaller transformers compared to continuous conduction mode designs, ultimately allowing for a reduction in solution size.
The LT3798 is available in a thermally enhanced 16-pin MSOP package. The LT3798E and LT3798I versions operate over a temperature range of -40°C to 125°C. The LT3798H has been tested and guaranteed to perform over a temperature range of -40°C to 150°C. Pricing starts at $2.25 per unit for orders of 1,000, and all products are currently available for immediate purchase. For more information, please visit www.linear.com/product/LT3798 .


Photo caption: Isolated offline single-stage active PFC flyback controller

Product Features: LT3798

• No additional power stage required with Active PFC
• VIN & VOUT restricted to external components only, VIN >400VAC allowed
• No need for optical couplers
• Total regulation of ±5% or more
• High efficiency
• Contains low harmonics
• Realization of compact solution size through the use of fewer parts
• Thermally Enhanced 16-Pin MSOP Package