MP2918 Sync Buck controller's datasheet leaves certain points unexplained.

[treez]

Hi
We are wanting to use the MP2918 Sync Buck controller. Its datasheet fails to explain certain things….

AAM mode
Do you know if the AAM mode (light load handling mode) can be used when the part is synchronised by an external clock?
Page 18, Fig 3 of the datasheet is supposed to show the difference between AAM mode and CCM mode…but surely all it shows is the difference between one mode where the inductor current is allowed to reverse, and a different mode where the inductor current is not allowed to reverse?

Synchronisation
Also, does the synchronising pulse have to be less in width than the minimum on time of the lower FET?
Also, presumably the “SYNCO” output is just the inverse of the SYNC input?....or is it an active_high clock which is 180 degrees out of phase with the active_high SYNC input?….Also, if its an active high clock, then how wide is its high_time?
….In other words, if the SYNC input is an active high pulse of 1us every 3us, then what does the SYNCO output look like?

MP2918 sync Buck controller:
https://www.monolithicpower.com/en/...Datasheet/lang/en/sku/MP2918/document_id/192/

 

[FvM]

Some points can't be answered clearly by the datasheet, my assumption is:

AAM. The question is if pulse skipping is implemented by stopping the oscillator or by ignoring clock pulses. The block diagram suggests the latter. If so, SYNC would still work in AAM, pulses are aligned with SYNC edge but some skipped with light load.

SYNC and SYNCO. According to the datasheet, SYNC is edge sensitive with no requirements for the pulse width except being > 100 ns. SYNCO is said to be 180 degree phase shifted, in other words its pos edge is centered between SYNC pos edges. Nothing is said about the pulse width which won't actually matter. May be it's 50% duty cycle. Surely not the inverse of SYNC in general, SYNCO also works with free running oscillator (EN/SYNC = 1).