I know this is an old product but it does seem to still be being offered for sale in various places. I’m a bit dosappointed with the hardware documentation - there seems to be nowehere (i can find) where a complete simple usage circuit diagram is shown - just the board circuit diagram and diagrams of bits of projects like the one in the video that’s linked from the product page.
A simple single page circuit diagram for a complete usage (inlcusing power arrangements) for flashing LEDs on and off could have been a great help to the pages of people asking questions. The question I have (which was asked by someone else, but not realy answered there) is what would be the maximum voltage that can be applied to VCC? The documentation (or at least those items I have found) does not make it clear that you don’t need separate feeds for the 5V DC which the TLC logic needs and the common +V which the LEDs take on the + side. Only by reference to the board’s circuit diagram can you learn that there is an on board 5V regulator that develops 5V from a single VCC feed - however there is no indication in any documentation, that I can find, of what the mximum voltage for VCC might be.
The datasheet on the product page (under ‘documents’) has it listed @ • VCC = 3 V to 5.5 V
Check out some examples here https://github.com/sparkfun/SparkFun_TL … 0/examples ; we also have this VERY complex example https://learn.sparkfun.com/tutorials/in … -led-array and some basic PWM examples if you search our ‘learn’ or blog areas of the site
Thanks for your reply - but it doesn’t really sort out my confusion. I still don’t see a simple usage circuit amongst the examples you supplied - and yes I looked at the complex example previously, but so far as I can see, the details of how the power is supplied are incomplete in the various diagram segments provided there. The other examples all seem to be just software and cover signal connections, but not power.
I believe the 3-5 volt range applies only to the VCC pin on the TLC5940 chip itself not to the overall board - those are the exact figures that the Texas datasheet quotes. But, according to the Sparkfun product circuit diagram, on this board the TLC5940 derives its VCC from a regulator whose input is VCC. So, if I feed 3V into VCC, the TLC probably wont even get 3V -from the regulator let alone the 5V that the circuit diagram says it gets.
Also, there seems no opportunity to decouple “VCC in” to the regulator and VCC which sits on one pin of each of the “OUT” ports - and according to the Texas datasheet those can take up to 17V. Which - since I see no way to seperate the VCC feed to the regulator and the “OUTxx” pins, brings me back to my question which is essentially this:
If I feed 12V to VCC (which is what my LEDs need), will the onboard regulator (which on my board is unmarked, so I can’t check its datasheet) be okay producing the 5V which the TLC needs?
Many thanks
Using a microscope I can just make out that the regulator on the board is marked 4A2D though I am not 100% sure about the “D” - the markings are very faint. This does some to be a somewhat vague part number though - applying to lots of different regulators which different fixed voltage outputs - and even cropss referred to completely different device part numbers. So not sure that gets me an further forward in knowing if this will take 12V at its input and still provide 5V output for the TLC.
I think I might just go ahead and try it… watch this space (for smoke!).
Well I tried it and ran it for an hour on +12V while using my temp monitor on the regulator and the 5940 - no problems at all. I had an Adruiono lighting up 16 pushbuttons (each with 12V @ about 20ma LED) in sequence. After a hour of that the regulator and the 5940 were only a couple of degrees c above ambient temp in the room. So I think we can say that these boards will run on 12V without a problem. I get that this is an old product now and probably end of life, but what a shame the documentation could not have made that clear.