How to connect TLC5940nt and ULN2003

I tested the arduino with just the TLC5940 and it worked.
I wired a ULN2003 like this:


It seems like the signal is inverted. When the LEDs should be off, they're on and vice versa.
Do you guys see the mistake?

The 2003 is an inverter driver.

Why does the signal not get inverted when I use PWM from the arduino?

And, should I buy a different transistor or can I fix the problem in the software?

Can you not drive them directly?

12-1-2013 12-21-40 PM.jpg

scottholtzapple:
Why does the signal not get inverted when I use PWM from the arduino?

And, should I buy a different transistor or can I fix the problem in the software?

It is not the PWM that inverts the signal but the fact that the TLC chip is a current sink and so is the ULN, if you want to avoid this then get a top switch Darlington driver, that is one that sources current rather than sinks it.

LarryD, the lights I'm using draw about 700mA

Thanks Mike. I'll look into that

the lights I'm using draw about 700mA

Your 2803 wont handle this.