The input stage of the converter generally consists of a rectifier, power conditioning stage ( PFC circuit), and smoothing capacitor bank. The block diagram below shows the various portions of an LLC resonant converter. These systems enjoy many high power applications, including in systems with AC mains input. Contrast this with a standard switching converter (e.g., buck or boost topology), where the output is controlled through the duty cycle of a switching signal. LLC Resonant Converter DesignĪn LLC resonant converter is a switching converter that controls the output voltage by selecting the appropriate frequency for a switching signal. When you’re ready to create your PCB layout for these systems, there are some points you should remember for safety, heat management, and noise suppression. You could implement the same type of control algorithm you might use for a buck-boost converter to accommodate a power supply with droop or excessive ripple, but you can get to higher output powers with this type of isolated switching converter. Once you look at control algorithms and methods for implementing a feedback loop, an LLC resonant converter design starts to show its value. These converters are key portions of high power systems like LED banks, appliances, desktop and server power supplies, and many other power conversion systems. Among the various types of switching converters and their topologies, LLC resonant converter designs are not often discussed until you look at application notes from power electronics companies.
DC-DC converters can be difficult to design and can even be dangerous, particularly when we consider switching converters with high current output.