Meanwell LPF Series Dimming Solved

[ScubaSteve]

Ah, after looking at it more I see what he's doing. Ultra conservative design (in terms of current draw through the Arduino). You really could simplify it and just use the NPN. You'd have to drop the value of R3 to 5-10K butit'd work just the same.

Thanks for posting this. It'd be great to see people doing more DIY electronics. It's intimidating at first but easy once you get into it. Stuff like this really helps!

[Vancouver Reefer]

oops i forgot to add on a 1K pulldown resistor between the Meanwell + and 0V. This will prevent the driver from going to 100% brightness in the event the driver circuit stops working or has a power failure.

Steve,

I tried using a NPN before and it would not drive the LPF series driver. Here is what i had tried before but with no luck:

Controlling + lead:




So next i tried this circuit using the 10v supply to control the - lead:




I then tried the following circuit as the 2 previous would not work. This i could get the drivers to dim but with the Arduino fading from 0-5v i could only get the circuit to output 3.5v-6.5v.



I hope the background helps.

[ScubaSteve]

Interesting. I'd have to run the math to check it but I think the problem you were having here was the 1K resistor. The transistor might not have been at saturation and so the gain may have been too low for amplifying the PWM. I'm surprised it didn't work. I use the same circuit to control the fans on my tank.

Good call on the pull-down resistor. I always surprised people neglect them, not just for safety but also to just have a nice product. Why would you want you LEDs going to 100% any time you unplug something?

[Vancouver Reefer]

I have been using the 2n2222 for all my power control on my controller with no problem, but those LPF drivers nearly got my controller launched out the window!

[ScubaSteve]

Time to make the switch to the LDD drivers

[Vancouver Reefer]

Next time!