Can LT3791 IC be used as an output voltage regulator?

F

Flyback

Well-Known Member

• Feb 12, 2014

• #1

LT3791 datasheet
https://cds.linear.com/docs/en/datasheet/3791fb.pdf

...I see the datasheet talks of fault modes being associated with the FB pin...but would this stop it being used as an output voltage regulator?

(..Pages 19,20 of datasheet)

 

ronsimpson

Well-Known Member

Most Helpful Member

• Feb 12, 2014

• #2

it was never designed for voltage feebback but it should work. pins ledshort and ledopen will not function right.

 

F

Flyback

Well-Known Member

• Feb 12, 2014

• #3

but when FB is below 400mV, it thinks its got an output short and goes into fault mode, discharging the soft start capacitor, also, if FB goes >1.25v, it goes into fault mode and stops switching?

 

ronsimpson

Well-Known Member

Most Helpful Member

• Feb 12, 2014

• #4

You are probably right. It was built for LEDs not voltage.
Try LT8705.

 

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crutschow

Well-Known Member

Most Helpful Member

• Feb 12, 2014

• #5

Why do you want to use an IC designed to power LEDs and use it for what it was not designed for? It's hard enough to design switching voltage regulators using components designed for that purpose without throwing some extra unknowns into the mix.

 

F

Flyback

Well-Known Member

• Feb 13, 2014

• #6

we want simplicity..and this has no trafo.

 

crutschow

Well-Known Member

Most Helpful Member

• Feb 14, 2014

• #7

What's trafo?

 

F

Flyback

Well-Known Member

• Feb 14, 2014

• #8

transformer

 

crutschow

Well-Known Member

Most Helpful Member

• Feb 14, 2014

• #9

It has an inductor. Most buck/boost converters also use inductors, not transformers. Still don't see a reason to use the LM3791 as a voltage regulator.