LLC Resonant Converter With Adaptive Link-Voltage Variation for a High-Power-Density Adapter

The output voltage of an adapter for a laptop computer should vary according to the load current in order to supply power to the computer. To satisfy this requirement, an LLC resonant converter with an adaptive link-voltage-variation (ALVV) scheme is proposed in this letter. The proposed ALVV scheme helps the LLC resonant converter to operate at a nearly constant resonant frequency and also allows for the optimal design of the converter. High power density and high efficiency can therefore be obtained. The proposed LLC resonant converter with the ALVV scheme is analyzed theoretically and verified experimentally.