UCC28065: About High switching frequency(Higher than 500kHz) PFC IC, but don't need interleaving.

Hello, 

The way the UCC28065 PFC controller is designed, it can operate long term with one one phase (channel, output) running and the other one not running, however, it always drives both phases at start-up to avoid the risk of CCM in the inductor.  This is explained at the bottom of page 19 in the UCC28065 datasheet.
If you are driving only one channel (Phase-A), then the gate pulses for Phase-B will have no effect, but the IC will behave as it is designed for 2-channel operation. 
You will have to accommodate this behavior in your design. 

The UCC28065 is designed to operate in transition mode.  It cannot operate in any other mode.  The high frequency range at which it is capable of operating is normally the result of light load and high-line input voltage.  Lower frequencies (usually much lower) can be expected at low-line and higher loads.     

If you want a PFC converter to operate at >500kHz all the time, you will need a fixed-frequency controller.  Most such controllers are CC-PFC and most of TI's more recent CCM-PFC controllers have frequceny limits around 300kHz or less. 
However, the UC2854A PFC controller can be programmed to switch up to about 800kHz.  This is a much older device made in a Bipolar process (UC prefix, not UCC which is BiCMOS) but it is still available and meets your frequency requirement.  Application notes to use this device can be found on the UC2854A product page, and some app-notes on theUC2854 page also apply to the UC2854A.   https://www.ti.com/product/UC2854A#tech-docs  and  https://www.ti.com/product/UC2854#tech-docs 

Regards,
Ulrich