Using the DOs as Current sinks

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BAM
Posts: 6
Joined: Wed Jul 29, 2020 9:22 am

Using the DOs as Current sinks

Post by BAM » Tue Aug 04, 2020 12:48 pm

Hello,

I have been trying to control a 12V RGB LED strip using a Controllino MAXI and its' PWM outputs. My problem here is, that the LED strip has a common anode which forces me to use the digital Outputs as current sinks instead of current supplies. On the pin header this works just fine when I use a small single RGB LED that is rated for 5V. When I plug the common anode of the strip into the screw terminal digital Output and connect one of the color channels to ground it works as well. But when I try to use the digital output as a current sink as stated above (common Anode connects to +12V and the color channels connect to the digital outputs) nothing happens at all. I have used a multimeter to see if there is any kind of current flowing but there's nothing.

Can the HighSide Switches only be used as a current supply?
Would it be possible to have a look at the datasheet of the HighSide Switch?

Regards,
BAM

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Jarda
Posts: 61
Joined: Fri Dec 14, 2018 10:52 am

Re: Using the DOs as Current sinks

Post by Jarda » Wed Aug 05, 2020 11:06 am

Hello BAM,

at MAXI is digital power output implemented by High Side Switch, that means it cannot pull down the output. On CONTROLLINO MEGA are some digital outputs implemented by Half-Bridge configuration and there it is possible - see MEGA product description.

If you want to use MAXI, you have use some additional transistor to be able to pull it down.

BR
Jarda

BAM
Posts: 6
Joined: Wed Jul 29, 2020 9:22 am

Re: Using the DOs as Current sinks

Post by BAM » Thu Aug 06, 2020 6:20 am

I see. Thank you for your quick answer!

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Jarda
Posts: 61
Joined: Fri Dec 14, 2018 10:52 am

Re: Using the DOs as Current sinks

Post by Jarda » Fri Oct 02, 2020 1:57 pm

Your welcome !
Enjoy the CONTROLLINO !

BR
Jarda

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