Need help with TLC5920 LED driver

[Sugiman]

tlc5920

I'm trying to run a matrix of 16x5 of regular red LED's using the TLC5920 and I was wondering if anyone had a sample working schematic that I could use as a reference. I downloaded the pdf but it was sparse on details for how exactly to set it up.

I'm using a PIC18F2420 to run it and have spi(in,out,clk), latch, blank, csel(0-2), and +5V and GND running from the PIC to the TLC5920. It runs fine but I found when I disconnect the +5V line it still runs as if were still getting the same juice as it was when the +5 was connected.

So, I was wondering if it was a design flaw on my part or something else I'm missing. So, if anyone has a schematic I could look at, I'd really apreciate it.

Thanks

edit: I have the 5V from the PIC connected to the VLED pins on the 5920

 

[adelara]

tlc5920

Did you ever get a reply for this ?

You cannot run +5V from the PIC to the TLC5920. The LEDs driver
need to have its own power supply, even if VANA, VLED, VLOG are
the same.
The PIC cannot drive these lines.

As for the other signals, they are alright. Each one need to be
independently driven.

Yeah, the documentation sucks... and amazingly, the information
on the internet is very rare too....