Is a detailed description of the UCC28950's ‘burst-mode’ operation available?
I think I understand how burst-mode is supposed to work, with TMIN etc. However, the data sheet talks about an ‘even number of minimum width pulses’ a lot, never saying exactly how many of such pulses are output. The datasheet shows six pulses on page 9, Fig. 2. I think 12, 18, … pulses would work just as well (with an correspondingly larger off-time before the next burst.)
My question is if it is significant that the datasheet says "even number of pulses" and not "six pulses" explicitly.
What I understand is that once the needed phase-shift drops below TMIN, a number of minimum-width differential pulses are generated with a time-delay inserted after them that is sufficient to keep the output voltage constant (obeys the loop controller integral command).
When the 'even number of pulses' is actually any multiple of 6, this scheme could result in low-frequency (audible) noise emanating from the supply’s capacitors and inductors. This is the reason why I want to know how the burst-scheme works.