problems with the TLC59116F (i2c LED driver with 16 channels and PWM)

I'm trying the TLC59116F with an arduino UNO R3. This IC is a i2c controllable LED driver with PWM and 16 outputs. The registers seem all loaded fine (I'm using the wire library directly, there are no libraries for this chip I think) here's a print of their contents I've done with a loop:

0:11
1:0
2:C8
3:C8
4:C8
5:C8
6:C8
7:C8
8:C8
9:C8
A:C8
B:C8
C:C8
D:C8
E:C8
F:C8
10:C8
11:C8
12:FF
13:FF
14:FF
15:FF
16:FF
17:FF
18:D2
19:D4
1A:D8
1B:D0

As you can see, all outputs are on C8 (200) which should be high brightness.. and all LED are active I think (the FF registers). I have attached an LED to OUT0 like this:


If I attach the led to GND instead of OUT0 it (of course) works fine. The IC talks fine on i2c therefore it shouldn't be burnt.. The IC power comes directly from the arduino 5v, which is in turn powered by the USB connection.

You haven't said what your actual problem is.

I'm not familiar with that chip but usually there's some sort of 'output enable' bit that has to be set in one of the registers.

Just setting a 'brightness' isn't enough.

I'm sorry I didn't check this topic any more.. I solved the problem (the LED wasn't lighting), it was just that you have to set the output max current by connecting a resistor (Rext) between pin 1 and GND. Now it works but I have a different problem..

The total current I can get out of the chip is around 180ma, and not 100ma per channel.. if I go higher it automatically shuts down. Quick question: 100ma was per channel, right? In the datasheet it's not really clear I think.. I hope it's not 100ma total output current, that would make it quite useless.

The data sheet is quite clear, it has a 120mA maximum output per channel.

Ok I’ve figured out the problem but I don’t know why it’s happening. I was using 5V for the LED, which has a voltage drop of around 2.8V. Now I’ve switched to 7.5V and it works perfectly, providing 120mA per channel (360 with 3 channels combined for a single white LED).

To better understand, why is this happening?
Thanks

Why what is happening, the voltage drop on the 5V line? It will be because it can't supply the current,