hgldr (or anyone else)-
You said:
"Make only one error ampiflier, based on the voltage loop. The output of this will feed the internal error amplifiers of the CMC ICs which you will set up as unity-gain followers....Now, all of your converters will switch at the same peak current and the input...
sreid -
I've seen some 4-phase controller ICs, but I haven't come across anything in the 100kHz switching range - thus the more custom design. I'd be glad to hear about any ICs in this range that are good for CMC.
There is just a lot of information out there, some conflicting I guess. The TI article I was going off of is
http://focus.ti.com/lit/an/slua101/slua101.pdf
where it states the case for bucks over 50% Duty cycle.
Ok attached is my PWM schematic, which I believe is complete - working on a simulation now. I'd appreciate a verification that I've captured the advice I've received correctly.
Still ahead are dialing in the error amplifier ckt, and reading up on slope compensation for these UC3842s.
Thanks...
Hgldr (or anyone),
Basic question. The datasheet to the UC3842B does show how to use an external clock synchronization, but I am having trouble conceptualizing putting 4 of these 90deg out of phase with each other. In the attached datasheet, Figs 21 and 22 are pertinent.
Does the internal...
Yeah warpspeed, after looking at the calcs there (even worst case duty cycle) that makes the most sense. Efficiency is the key for us over cost, but why is there so much out there that says synchronous FETs are the way to go? Is that just for low IV applications?
I like this simplified approach hgldr. Turns out the controller I wanted to use has a min freq of 250kHz, which is higher than we'll be I believe. (looking at the 60-100k range).
The UC3842A datasheet is lacking in application detail, so I'll look around for an alternative.
Side question - Any...
Thanks all for the responses:
Warpspeed, great response - I'm looking at ripple regulation circuits right now. This is an unusual design as well - because output current ripple is not the concern so much as ripple current seen by the source (think battery or fuel cell - current source). So a...
I'm an entry-level engineer, and I have a design question for the forum:
I'm designing a multiphase buck DC/DC converter which will convert roughly 65VDC to 52VDC at up to 150A. I'm using 4 phases, so inductors, etc will be designed to about 40A/phase, MOSFETS will be paralleled for less (about...
