First PFC and hybrid flyback combo for GaN-based USB-C chargers

First PFC and hybrid flyback combo for GaN-based USB-C chargers

Technology News |
By Nick Flaherty

Infineon Technologies has developed a highly-integrated combo controller for USB-PD chargers using gallium nitride transistors at high frequencies.

This move to higher frequencies reduces the size of the magnetics in the design, allowing smaller chargers with higher efficiencies than silicon However this requires power factor correction (PFC) when used with a flyback architecture and this is usually implemented in a separate chip,

Infineon’s XDP digital power XDPS2221 controller integrates an AC-DC power factor correction (PFC) controller with a DC-DC hybrid flyback controller (HFB), also known as asymmetrical half-bridge (AHB), in one single package.

Combining the two stages in one chip allows the regulatory requirements can easily be met.

The controller also has a synchronous PFC and HFB burst mode operation for the lowest possible no-load input standby power performance. The quasi-resonant multimode PFC stage is enhanced with automatic PFC enable/disable functionality and adaptive PFC bus voltage control to maximize average and light load efficiency. Optionally, the integrated PFC function can also be disabled, to support the use case with any kind of external PFC Controller.

The chip also integrates all the gate drivers and a 600 V high voltage start-up cell for the initial IC voltage supply and the certified active X-capacitor discharge enable a low external bill of material (BOM) and component count.

A zero-voltage switching (ZVS) HFB topology with GaN transistors provides high levels of efficiency across various line/load conditions, with wide input voltage and outputs of up to 28V to meet the latest USB-PD rev 3.1 Extended Power Range (EPR) specification.

The hybrid flyback stage uses peak current control operation for robust regulation and fast dynamic load response. To ensure ZVS operation under all conditions, the hybrid flyback features ZVS pulse insertion, including body diode cross-conduction prevention in discontinuous conduction mode. Additionally, XDPS2221 also provides easy to configure parameters via a graphical user interface to optimize system performance.

The XDPS2221 combo controller for PFC-boost and DC-DC HFB is available in a DSO-14 package and can be ordered now and will be shown at electronica 2022.

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