Yep, even in the slowest slew rate (0.001A/ms) that I can set in the load, 0-7 is still having trouble
I suspect it is the overcurrent protection features. So double check that your load is behaving correctly, look in detail at what is happening on the Isense pin and reed the OCP portion of the datasheet to see if it can make sense to you.
I mean at the moment you have accomplished a solid 5A supply, although the goal is 7 right?
When you have no clue on s.t.
Experiment is what you need.
Try decrease the sense resistor and as you are parallel the Isense.
Very basic error might happen when error is in parallel you ends up in a huge error.
+5% * +5% * n = ?
So reduce the Isense or increase I sense and see what response u get.
I think we forgot to adjust the Rcomp and Ccomp?
But still, why no MPS engineers helping this
This is not logical your design requirement is based on the very beginning of this post if inductor and sense resistor and frequency is not adjusted there are no way you need to change the RC compensation.
If RC compensation is having trouble the converter won’t even function on 5A or below sub harmonic oscillation must occur on current base converter.
You need to keep calling MPS engineer until they show up.
BTW usually external mosfet driver is not a good product for any converter company to help out.
There are too many uncontrollable factors so you are very sure not to hear from them.
Bests,
Brian
Maybe I’ve done yet another unprofessional thinggy on the RC comp: Wrong calculation. double check wouldn’t hurt tho.
Relay the last modified issue here again the post getting long and start to get lost.
What current issue you are trying to settle?
Startup over current lockout?
Spike false triggering on the current sense hence triggering driver protection?
Well just for fun try 5X the comp cap see what happens, perhaps the in the load step the response is so quick if pushes you into overcurrent.
No the load step response is not fast at all as the slew rate is set to 1A/1s aka 1mA/1ms for 7A you took 7s to ramp up if the data is correct on the previous post.
This is slow as hell.
almost same as gentally ramping up the current by hand and you had said the issue kept the same.
It is weird, I wonder what the load is really doing? I like resistors, they are nice and predictable.
ikr.
the load was in CC mode all the time. but just in case I’ll try on another load later. BK Precision stuff should be reliable.
for the slow slew rate same thing could happen if I used a larger inductor value. Despite the calculation should use a 3.3uH Inductor, but it can fail even in 5A. I really need to look twice at the RC comp value, seems to make sense now.