PWM dimming controller circuit

[aiq25]

I was wondering do you need any type of filtering or capacitors at the input of LED drivers for PWM dimming? I have some Meanwell drivers that have PWM and I'm not sure if I should provide any type of filtering at the input of these drivers. I'm using PWM using Arduino and I have a circuit wired up that seems to work.

I'm also using a Meanwell 36VDC output DC supply. I tied the ground from the output of this to the ground on my Arduino, I feel a little uncomfortable about this. Since I blew two Arduino boards before somehow, I think the there was some kind of grounding issue. Would a opto-isolator be good to use to separate the two grounds? I have never build a circuit with two separate grounds, so I'm curious about it.

 

[Sisterlimonpot]

No, You'll be perfectly fine without it. It's been a while since I've used an arduino so Ill leave that to the others to answer.

 

[Gorgok]

One thing to remember is the signal you are sending from the arduino is 5V max. Some drivers can use varying voltages on pwm, some can't. A 100% PWM signal to an ELN-60 would be 50% in its mind, since its expecting a 10V signal.

 

[mcgyvr]

The grounds must be connected to work properly. You did NOT blow boards from having a common ground.

And you do not need caps.

 

[aiq25]

The grounds must be connected to work properly. You did NOT blow boards from having a common ground.

And you do not need caps.

I'm thinking it might have been ground loop, not sure really. But yea I'm thinking it wasn't a grounding issue but not 100% sure.

One thing to remember is the signal you are sending from the arduino is 5V max. Some drivers can use varying voltages on pwm, some can't. A 100% PWM signal to an ELN-60 would be 50% in its mind, since its expecting a 10V signal.

I'm using the LDD-700L drivers with a NES-350-36 switching power supply. This is a stupid question but the PWM is suppose to be at 5V, correct. I'm assuming that since it's coming out of a micro.

 

[mcgyvr]

I'm thinking it might have been ground loop, not sure really. But yea I'm thinking it wasn't a grounding issue but not 100% sure.



I'm using the LDD-700L drivers with a NES-350-36 switching power supply. This is a stupid question but the PWM is suppose to be at 5V, correct. I'm assuming that since it's coming out of a micro.

Ground loops are a problem in audio/visual systems as they may introduce noise/humming. They are not a problem with this application at all.

You tie the grounds together so the voltage levels are based off the same potential zero point.


and yes the LDD drivers require 5V PWM...
Have Fun!!

 

[Gorgok]

LDDs only require 2.6V on high for PWM, so even a 3.3V PWM would work. But they can handle up to 6V on high, so arduino works just fine.

 

[O2Surplus]

Put a 220ohm resistor between each LDD-H and it's respective Arduino PWM pin to prevent short circuits & more "blown" Arduino's. The 220ohm resistor will limit the current in each PWM circuit to around 22ma per channel. That's well below the Arduino's 40ma per pin limit.

 

[aiq25]

Put a 220ohm resistor between each LDD-H and it's respective Arduino PWM pin to prevent short circuits & more "blown" Arduino's. The 220ohm resistor will limit the current in each PWM circuit to around 22ma per channel. That's well below the Arduino's 40ma per pin limit.

Thank you. Maybe something was shorting out and the Arduino was trying to drive too much current. This makes sense.