Q:

I was wondering if I can dynamically control the PFM/PWM operating mode of the TPS62400 by setting the MODE pin high or low during operation?


A:

The datasheet clearly answers your question:

"For additional flexibility, it is possible to switch from power save mode to forced PWM mode during operation. This allows efficient power management by adjusting the operation of the converter to the specific system requirements."

The datasheet gives additional timings regarding how long it takes the device to transition between the modes.  Be sure not to toggle between the modes so fast as to accidentally appear as the Easy Scale protocol.