constant current controller

[Rujul Desai]

hi,

what is the meaning of inductor current critical mode?

 

[treez]

it means that you have an smps where as soon as the inductor current falls to zero, the driving voltage is again forced across the inductor and the inductor current begins to build up again. So the inductor current falls to zero , but does not languish there.....in other words, the inductor current is triangular and not trapezoidal, and there are no "gaps" of zero inductor current, just "Points"

 

[Rujul Desai]

Hi.

Thanks for reply and help.
can you tell me how it work or use in constant current output circuit. ?

 

[treez]

it can be used in constant current output, though is not particular to it......look at BCM Control IC's for led drivers....I think the UCC28600 is one....I also think linear.com do the LT3799

"cRITICAL CONDUCTION MODE" , WHICH YOU SPEAK OF, IS ALSO CALLED "boundary CONDUCTION MODE"
TO REGULATE CURRENT, YOU JUST CLOSE THE REGULATION LOOP AROUND A CURRENT SENSE RESISTOR. (sorry about caps)

 

[D.A.(Tony)Stewart]

This is an example https://www.fairchildsemi.com/application-notes/AN/AN-6921.pdf

 

[Rujul Desai]

Hi,

What is mean by Non isolated Buck LED Driver?

And what is isolated transformer?

Thanks