Author Topic: Remote Powering the Differential Receiver boards  (Read 288 times)

Offline Tory Street Lights (NZ)

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Remote Powering the Differential Receiver boards
« on: June 07, 2019, 09:24:59 AM »
Is it "Kosher" to "back feed"  the Differential Receiver board power from the Pixel strings themselves, I will not be using any of the DC distribution capabilities of any of the Falcon gear as all my Pixel strings are individually powered, I only need the data from the boards.  I successfully ran Pixel sticks in this manner previously and it worked fine. With four "back feeds" it should be a relatively stable supply


My main concern being that as the board has a 5 volt Regulator on board, and I am using 5 Volt Pixels, with the regulator in the way it will not be doing much apart from dropping it's differential voltage to the two IC's. By the look of those two chips, it will not require very much power to drive the board, one being a Cmos device.


Thoughts  ??? 

Offline Sawdust

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Re: Remote Powering the Differential Receiver boards
« Reply #1 on: June 07, 2019, 03:13:51 PM »
Typically backfeed is ok, but can have problems when load causes voltage drop below the required level of the receiver board.

For this application, we can eliminate any possible receiver board problems by getting a little creative on your wiring:
Since you need no voltage at the 4 ports, do not connect the power there....Assuming all pixels are coming from same power source, tie all pixel power together and connect the pixel power lead(s) to the receiver board V+.
Ground is common so no need to duplicate ground connection.
If pixels come from different sources, only tie together those from same source and land on Receiver V+ - - Do Not Connect the others.

Couple things to think about.
Make sure your ground are large enough to carry data & V-
Make sure you have extra capacity.  Too much load will shut down the receiver until power is at an operating level again.  Suggest running those pixels at a reduced brightness.like 60%.

« Last Edit: June 07, 2019, 08:39:55 PM by Sawdust »

Offline Tory Street Lights (NZ)

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Re: Remote Powering the Differential Receiver boards
« Reply #2 on: June 07, 2019, 08:56:48 PM »
Thanks Sawdust,  fully understood.  I don't think that there is much wiring creativity necessary as the V+ Pixel sockets on the board are already connected to the External DC in V+ screw terminals via the fuses :-)   


In my installation, the Data inputs to the Pixel strings and their DC inputs are all terminated at the bottom of the Pixel string and have very heavy DC cables from the Power supply to the string, so there should be minimal voltage drop at that point, which will naturally be passed on to the Extender board.  Yes lowered brightness will be involved as the Pixels way overpower (in brightness) the original LED's that they are sequenced against, so that will also help  :-)


To help regulate/smooth any rapid fluctuations of the DC  at the board I could put a 1,000mfd (or bigger) Capacitor across the board using the DC in terminals to attach it.


Asking this question was not trying to be clever, just trying to simplifying the wiring  :-)

Offline Sawdust

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Re: Remote Powering the Differential Receiver boards
« Reply #3 on: June 08, 2019, 07:46:19 AM »
I have a policy of not connecting the pixel power lead if not feeding power to the pixels from that port, including back feeding....hence my process for creative wiring.  I use multiple 5V transformers on diff receivers (one per port, injected) with one being 12V. Not connecting power on Differential Receiver ports eliminates the possibility of miss connecting and paralleling 2 or more transformers.

Offline Tory Street Lights (NZ)

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Re: Remote Powering the Differential Receiver boards
« Reply #4 on: June 08, 2019, 09:57:22 AM »
I have a policy of not connecting the pixel power lead if not feeding power to the pixels from that port, including back feeding....hence my process for creative wiring.  I use multiple 5V transformers on diff receivers (one per port, injected) with one being 12V. Not connecting power on Differential Receiver ports eliminates the possibility of miss connecting and paralleling 2 or more transformers.


Fair comment, best not to introduce potential problems, food for thought  :-)

 

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