problem with 3w led driver pwm

I have a sure electronics led driver with mbi6551 chip and it does not respond to own. Even if I ground the dim pin on chip, which should make it's output 0 it is still at full power. All 3 drivers I have act this way. Any help or ideas would b great.
Thx
Justin

Stop crossposting and, as previously requested, provide a link to the product you're using.

Sorry about. The repost. I couldn't find my other post but here is the link http://www.sureelectronics.net/goods.php?id=1320k

THe PWM pin looks like an enable to me... It's marked enable (EN) However if you read the data sheet carefully there is a missing wire. There is no ground connection on the example schematic for the PWM driver and the LED controller. Left floating it might operate erratically, Connecting to the LED controller will surely be problematical, with out a return (ground) lead. I should think it would go to the PSU ground as the led is likely not grounded. It probably is the current feedback sense for the Constant Current Driver circuitry as it much easier to do "Low Side" sensing than it "High Side"... low will be a couple of volts above ground and that voltage is used to sense the LED current. Otherwise it would be Vsupply - Vsense, varying about a volt or so from Vsupply...

I think you might have overwhelmed him with that response, Doc :wink:

Reading the application note for the MBI6651 you're correct that the cathode side of the LED cannot be treated as GND. dostjusting, the DIM connector would need to be connected all the way to the other side of the board to the GND connector to turn the LED off. Oddly enough the appnote doesn't even mention what happens when you leave the DIM pin floating.

If you're using an external power supply for your LED as the schematic describes and you're trying to control the DIM pin with an Arduino, make sure that you have a wire connecting the GND on the power supply to the GND on the Arduino.

That's what I said... Sorry for the Lecture... It was a little advanced for the question... However at least the answer... sort of was in the first sentence. The rest of that stuff was a lesson that DID NOT need to be here... now and the explanation tor erratic or non operation was way too long, it was however reasonably accurate.

Doc

T hanks guys I will accept anyinfo even if it's over my head at least it is something more to wOrk with. I did not have psu and arduino. Linked by ground I will try this and let y'all know. thanks again for replying