Standard series resonant converters have excellent full load efficiency, but suffer from reduced efficiency at lighter loads as the switching frequency increases greatly. LLC resonant converters are a simple development of series resonant converters. Series resonant converters use one inductor (L) and one capacitor (C). LLC converters use a second, uncoupled inductor to greatly reduce the dependency of the switching frequency on the load. They are therefore highly efficient at a wide range of loads.

In the FSFR family, the method of switching is Zero Voltage Switching (ZVS), which results in very low EMI and very high efficiency. The diodes in the MOSFETs have fast recovery times which allows small deadbands in the switching cycles, further improving efficiency. In addition to the LLC resonant converter, the FSFR family can be applied to series resonant converters and parallel resonant converters.

Key Features

• Variable Frequency Control with 50% Duty Cycle for Half-Bridge Resonant Converter Topologies
• Very High Efficiency due to Zero Voltage Switching (ZVS)
• Fast Recovery Times in the Internal MOSFETs
• Fixed Dead Times, 350 ns
• 300 kHz Maximum Operating Frequency
• Pulse Skipping for Frequency Limit at Light Load Conditions
• Remote ON/OFF Control
• Integrated Protection Functions like Over-Voltage, Overload, Over-Current and Thermal Shutdown

Applications

• Industrial Power Supplies
• Telecom Power Supplies
• Audio Power
• LCD and PDP Television Sets
• Industrial PCs and Servers
• Adapters

Ordering Information