SwitherPro- Compensation vs load current

Dave Bryant

Other Parts Discussed in Thread: TPS54140

I am using SwitcherPro to design a pretty basic 180-30V to 3.3V buck converter with a max output of 1.375A. I assume the loop plot that SwitcherPro generates uses data relative to a 1.375A output, but in my design that is a worst-case output (multiple fault conditions). The circuit should be operating closer to 400 mA most of the time. Does the loop plot still apply at that load?

over 12 years ago

0 JohnTucker over 12 years ago

TI__Guru**** 191445 points

What part are you designing with? It helps if you put the part number in the post title.

0 Dave Bryant over 12 years ago in reply to JohnTucker

Prodigy 60 points

Sorry. I had it there originally, but thought the topic was more specific to SwitcherPro than to any specific device. The one I'm using is a TPS54140.

0 JohnTucker over 12 years ago in reply to Dave Bryant

TI__Guru**** 191445 points

Switcherpro may do subtly different thing s with different parts. For TPS54140, the loop response will be for the specified current. You can change that by clicking on "edit inputs". there is a box on teh bottom to check if you want switcherpro to change the components based on the new inputs. leave it unchecked to keep the same components (that it what you want to do)

0 Dave Bryant over 12 years ago in reply to JohnTucker

Prodigy 60 points

Thanks, John. That's what I suspected, but I wanted to be sure that changing the current without changing the schematic was legit. It doesn't look like changing the current in my design had a significant effect on the loop characteristics.

0 JohnTucker over 12 years ago in reply to Dave Bryant

TI__Guru**** 191445 points

one thing you might watch out for...I am not sure that switcherpro models the loop properly in DCM mode.

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SwitherPro- Compensation vs load current