High Power LED Driver, 9 amps

[SUBjohan]

Is everyone happy now? :ironic:

Yes SIR!!!😀😀
And now go do some tests so we can order some 😉

Technical question, how do you measure the current? By Shunt resistor or via a different way?

Greetz Johan

 

[fppf]

Parts should be here next week.

Current is measured by shut resistor. But its a resistor designed for current measurement and is configured as a kelvin measurement.

 

[rokspydr]

WOW this great, thank you.

 

[Aircraft800]

Yea, just go ahead and put me on the buy list. You're obviously a electronics guru, and your component talk is way above my head.



Thanks for the updates!

 

[fa__]

All this looks very nice and is interesting to read, thanks :thumbsup:

 

[nailbender]

Hi

I just saw these cool.

I would be in for a 3 or 4 of these and I think the price to be fair for what you are doing and the parts needed.

thanks for considering these.

Dave

 

[AaronM]

fppf,
Can you make this driver work with a Luminous CSM-360? It requires four times the voltage of the SST-90 and I know I can only expect one fourth the current...still, the efficiency would amazing.

 

[fppf]

fppf,
Can you make this driver work with a Luminous CSM-360? It requires four times the voltage of the SST-90 and I know I can only expect one fourth the current...still, the efficiency would amazing.

Yeah, we can drive that one too. It would require some changes to values but should not be an issue.

 

[Pin]

Yep, count me in...
...this is what we've all been waiting for (and not smart enough to do ourselves). I think the price is fair....and I think we take your effort for granted...so, "Thanks!". 😀

Now, to pull my finger out and get started on a host...

 

[paetzi]

I´m also in for one.
But i still have a question.
If i take the pot option. Is it still possible to disable the driver with a switch?

 

[AaronM]

Yay!
I'm in for one with a 12~13V output.

 

[fppf]

WOW, and who said the USPS is dead?
I have the parts in hand already! :twothumbs

I will review the board layouts one more time and confirm package sizes and spacing. I should be able to order boards tonight and maybe just maybe have some built by the weekend.

 

[rokspydr]

wow pretty fast

 

[AaronM]

Is it a buck only driver? I suppose it wouldn't need to be anything else for a single SST-90. Any idea what battery voltage I would need to maintain for my propposed 13V load?

 

[fppf]

Is it a buck only driver? I suppose it wouldn't need to be anything else for a single SST-90. Any idea what battery voltage I would need to maintain for my propposed 13V load?

Yes, its only buck, no way buck/boost would fit on this tiny board.
The design will let you operate all the way into and past dropout. However the way the controller measures and controls current when you get to drop out you will see LED current increase by half of the inductor ripple current, which is about a 0.5 amps increase. So I would suggest keeping Vin a little above the voltage of Vf at If +0.5 amps. There is a lot of inductor ripple current because you need a large inductor to carry the current but we have no space for a large value inductor. So I had to use a smaller inductor with a lot of caps.

 

[paetzi]

If the driver is build for the use with a 100k pot can it still be turned off via a switch?

 

[lucca brassi]

@fppf

May I ask you which IC you will choose for current driver.


At the moment I make some experiments with LT3743 (buck), but I made tests only with resistor instead of LED ( waiting on SST :tired🙂 ,need some fine tuning..... then aluminium PCB ( on next company order)

Regards

 

[fppf]

If the driver is build for the use with a 100k pot can it still be turned off via a switch?

Yes, Disable line always functions.

@fppf

May I ask you which IC you will choose for current driver.


At the moment I make some experiments with LT3743 (buck), but I made tests only with resistor instead of LED ( waiting on SST :tired🙂 ,need some fine tuning..... then aluminium PCB ( on next company order)

Regards

I'm not willing to share that, sorry, maybe after I start making them.

 

[fppf]

So I did some more thermal analisys on the board.

I think there is going to be a heat issue with the mostfet still. All the other componets should operate about 20 degrees C above amdient, but the fet is looking close to 70-80 degress. Which means, inside the light it may cause it to over heat because of the rise in ambient temperature.

How do you guys feel about me using a TO-220 package that needs to be heat sinked? It would fit on the board and we can lay it down so it would not add that much hieght. We are just pumping a ton of current. The other option I'm looking into is using a larger SMT package, but because the board is so small there is not a lot of heat transfer happening there. But a larger fet would have lower Rds which will help a lot.

 

[fppf]

Ok, I think I found an SMT fet that will handle the power without cooking.
I also changed the board layout to better dissipate the heat.

I should have boards on order tonight. But it maybe next week until I get a chance to build them up. More to follow.