1.5A Constant Current Linear Regulator for LEDs for

Step 6 Let the Blinding Begin!

With the .1" spacing on the pinout of this board you can very easily breadboard your project. Here we are powering a string of 3 x K2 Luxeons (140 lumens per led) from a 12V wall wart capable of supplying 3000 mA.

The performance of this chip is pretty amazing. At 1500 mA the driver board is barely warm to the touch when driving leds continuously.

Note: This design is for a strobe light where the leds do not stay on very long. For continuously running the leds you MUST mount them to a heatsink to dissipate the heat that is produced.

All parts for this design can be found at Mouser or Digikey:
Here's the BOM

Driver IC - STCS1

Comments

[cahillicus]

 Is there a way to up the output?  I want to be able to drive 6  3.7V LEDs at 800-1000mA from a car power source (14V).  Thanks

[ohararp]

 You'll need to do some reading up on leds.  But basically you will only be able to run 3-4 leds in series based on the forward voltage of your supply (14V in this case).  You could run more, but you would need to run them in parallel to do this using a single driver.

[cahillicus]

I am actually trying to build 2 light housings running 6 LEDs each.  However, I want to power each light separately.  Do you think i should just run 2 drivers per light (3 LEDs per driver)?  Or, would running them in parallel as you previously mentioned.  If so, how would you go about it?

[ohararp]

Since these are high power led's I would avoid running them in parallel (because offsets in resistance can cause one led to be driven harder than anot her-leading to shortened led life). 2 drivers for 3 series leds would be the way to go IMHO.

[conntaxman]

Would the STCS2PR driver work using the same pin connection?This one has 10 pins as the STCS1PHR only has 8 pin connections.Just the STCS2PR is bigger to work with.
TKS
Johnny

 

[ohararp]

 Glad to see you got everything working!

[conntaxman]

ohararp, Could you answer me a question seeing that you seem to know alot about these chips.With the "STCS1" in the [Blue dia].Application diagram they dont connect the "EN" pin ,but in the cir. in DIY. they connect the EN pin to the "VCC". Also it is the same for the "" STCS2 "" it is the same,they dont connect the EN pin. So in both dose the EN pin have to be used?it is called the Shut down pin.
I connected it in your or the DIY. dia. and it works fine.I didn't disconnect it to see if that would have any effect.
I want to wire up one useing the STCS2.but don't know  either to connect it or not.
Tks
Johnny

[conntaxman]

hello ohararp. Would you know if I would be able to use a 10 ohm resistor in place of a .05 ohm in the cir. when using a "STCS2" it is coming from pin [ FB ] and [Source] .
Is that being used to regulate the voltage? I don't know.First time using these chips.
tks
Johnny

[ohararp]

 Sees like a pretty simple calculation to me - See Section 7.1 of the datasheet.
RF=VFB/ILEDS=100mV/700ma=142mOhms

[conntaxman]

Hi ohararp. I just read your reply.After which i just laughed at myself because I didn't know how to figure out how to make a cir. My trade was Plumbing/heating. I didn't read "section 7.1" yet. I guess what I'll do is just try a 10 ohm in place of the 5 ohm and see what happens.Hope that I don't see smoke.lol. well then i'll know that you can't use a 10 ohm.
I glad the other cir. works very good.
Thank for the reply and have a nice day.
Johnny

[conntaxman]

Would the STCS2PR driver work using the same pin connection?This one has 10 pins as the STCS1PHR only has 8 pin connections.Just the STCS2PR is bigger to work with.
TKS
Johnny
reason is ,that it is a little bigger to solder with the pre made pc. board.
tks again.
very nice cir.

[ohararp]

 It looks very similar...you'll have to compare datasheets though...

www.st.com/stonline/products/literature/ds/13968.pdf