pwm for 3w led driver not dimming

I am settingup a led system for aquarium and all is good except the led driver wont dim leds. Even if i connect dim pin of IC to ground which should turn led dimmer to 0 it stays at full current. The driver is from sure electronics and the ic is model numet mbi6551. Any help would be great.

Any help would be great.

Then you had better provide some information. What code? What IC? What circuit? Link to driver, why should I have to google it?

We're not clairvoyant, but happy to help if we have enough information.


Google isn't forthcoming - link to datasheet?

I assume you are doing the same thing as I did for my LED aquarium lighting. I used the arduino to drive a set of 4 Meanwell Eln-60-48p pwm drivers.

Most LED drivers take a 10V pwm signal to power them, (the one's popular in the aquarium trade anyway) the arduino only outputs a 5V pwm signal and you will need a few components to ramp that up. It is a quite simple circuit, and I have schematics of mine, if you would like to see them see them send me an e-mail at

But for your problem when you are outputting a 0 to the pwm output on the arduino there should be a constant 0V, which would dim the drivers to 0 regardless of the signal level. I'd assume there is an issue with the code, wiring, or what pin you are using on your arduino.

Could you post your code?