TPS54623: TPS54623 for dynamic voltage scaling

Terry,

The OVP function is built in and cannot be disabled.  In your case if you have the voltage set for 1 V with a voltage divider of 10 k and 15 k, then switch to 0.9 V operation by setting the bottom resistor to 20 k, then the FB voltage will go temporarily to 0.666 V.  That would be enough to trigger OVP.  It would depend upon how fast you switch between voltages.  OVP is not latching protection.  It would just slow down the rate of change of the voltage transitions.  You would potentially see skipped pulses in the switching node.  Also I see you have 1 uF in parallel with R359.  That may introduce some stability issues as it is quite large.

Terry,

You will minimize the effect by slowing down the transition, not making it faster.  The 1uF cap in parallel will affect the loop response.  You should probably not use it.  I would slowly turn off/on the FETs from the gate drive side.