Flyback controller delivers power density and efficiency

Designed to meet the increasing demand for higher power density and energy efficiency, Infineon has expanded its XDP family, adding the first application-specific standard product based on an asymmetric half-bridge flyback topology.

Available in a DSO-14 SMD package, the XDPS2201 is a highly integrated, multi-mode, digital and configurable hybrid flyback controller targeting high-density AC-DC power supplies, including USB PD fast charger and adapter applications.

The device combines a traditional flyback topology with the performance of a resonant converter, which allows natural soft switching and reduces switching losses associated with high switching frequency designs.

The controller enables zero voltage switching (ZVS) and zero current switching (ZCS) across AC line inputs, load conditions and variable output voltages. A feature which is highly beneficial for high-frequency designs with a planar transformer that can typically be found in USB PD charger applications.

To achieve optimised performance under various output voltage, load and line input conditions, the XDPS2201 comes with an intelligent, self-adaptive digital algorithm. It supports a multi-mode operation to ensure that the best-fitting operation mode for each condition is selected to yield a continuously high efficiency level. The hybrid flyback controller also integrates a comprehensive suite of protection features, including brown-in and -out, dual-level overcurrent, output over-voltage, output under-voltage and over-temperature detection.

The asymmetric half-bridge flyback topology allows the implementation of CoolMOS MOSFETs to achieve higher levels of system efficiency and power density.

The XDPS2201 is driving both high- and low-side MOSFETs in an asymmetric control manner. The product features an integrated high-side driver that allows BOM savings of up to 20 external components. The topology enables a snubber-less design and the use of high voltage MOSFETs from 500 V and up, reducing both the number as well as the cost of components.

The XDPS2201 is able to support high power density designs with an efficiency of up to 93.8 percent and more than 92 percent on average across different AC line and load conditions.