Help with 1280 - TLC5940NT + Led strips

Other Hardware LEDs and Multiplexing
4

You have a number of wiring errors:-

  1. Don't join the pin 16s together.
  2. Iref is on pin 20 not pin 22 as you have it
  3. Ground is pin 22
  4. There are no decoupling capacitors on the supply.
  5. There is no common connection to the anodes of the LEDs.