As for control...Treez every current mode buck converter (billions) has an outer voltage loop with less bandwidth than the inner CMC loop and it works great because the inner CMC loop can be very fast. There is no difference here, you just need to have decent layout routing the control signal to 2 controllers (put them near each other).
Thanks, yes I agree with you in the specific example which you give here..ie the “inner current loop of a current mode controller”…..but isn’t the situation of the master-slave approach detailed by Klaus above slightly different?......i mean, both the current regulating slaves, and the voltage regulating master , will both be “current mode controlled”……. And it’s the outer feedback loop of both of these which we are considering…..neither will be as fast as the ” inner current loop of a current mode controller”…..and as discussed, these "slave" outer current loops can’t run at the same bandwidth as the "master" outer voltage loop else they will “fight” each other……….so the outer voltage loop of the master will have to be made slower than the outer current control loop of the slaves….and the end result of this…..is that you have an overall sluggish voltage control loop....but i do see what you mean by your example, just that i dont see how either our master or slave outer feedback loops can be made as fast as the ” inner current loop of a current mode controller”...apologies if thats not what you meant anyway.
I might be wanting my cake and eating it however, because I suspect that all groups of power supplies subjected to current sharing regimes end up with an overall sluggish feedback loop….even the ones kindly suggested by WWFeldman above (ie using UC3907)
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Also thanks for your details of the interleaving controller……..i appreciate your help here.
The thing is, we are considering a way of making totally separate power supplies to share with each other, into a single voltage regulated output….and really, those interleaving controllers need to go on the same PCB, and are, effectively, just one overall "dual power supply"….
I apologise because the reason we are looking into this isn’t specifically because of the Buck example that I gave here in the top post…its because we wish to do a 12.5Kw, 800V power supply, from a 400V PFC’d output. (input is mains 240vac)
...The best way we can think of is to have four sets of 3.15kW converters each comprising an interleaved 3.15Kw Boost PFC, feeding a 3.15kw Dual LLC converter with isolated stacked outputs (2*400v for 800v)……..then we will make the four 3.15kw, 800v outputs go into one 800v output…by use of a sharing technique between the four of them...this is why we are interested in "sharing" techniques.
(Basically, we need a 800V, 12.5Kw power supply from a 240vac mains input.)