LM5175: operation mode transition of Buck, Buck-Boost and Boost

Part Number:LM5175

I would like to know operation mode transition timing.

LM5175 has three operation mode, Buck, Buck-Boost and Boost.
What is the trigger of transition?

For example, LM5175 transit from buck mode to buck-boost mode when voltage difference between VIN and VOUT becomes lower xx V. or Duty is higher xx %.

Best Regards,
Kohei Sasaki