What is a LED driver??

I've looked around trying to find out what the difference is between shift register and an led driver. Is a driver such as this: http://www.ti.com/product/tlc59116

Basically a 16 channel shift register which also controls boosts current (like a transistor shift register combo)? Or does it simply control current between channels more evenly than a shift register without bumping up the current?

I've seen many tutorials on how to use shift registers to light extra LEDs, but since output pins are limited to a certain current (for instance 40ma on the Arduino), how do you get around this? Seems like a shift register would still only pull 40ma and just spread it among 8 LEDs.

For that matter, how do these videos show 16 LEDs being lit off 3 PWM pins when the LEDs would draw 20ma*16=320ma and the pins can only provide 60ma? Thanks for any help on understanding this!

 

Led driver is a PCB that contains either boost or buck or buck/boost converter to drive a serie of LEDs, it does also different special functions like dimming and current regulation.

 

Wow, thank you! Been on here for a week asking MANY questions and that was definitely the most informative answer I got (although that might be due to my quickly growing knowledge of what the hell people are talking about).

The videos I was referring to used 2 shift registers daisy chained off 3 pwms to run 16 LEDs. Don't think they were multiplexed (and don't think that would be a solution for my project because my LED's will be moving somewhat quickly and I don't want there to be any artifacts), but probably just run at a low current.

Would the TLC59116 and a microcontroller alone allow me to drive 5 rgb LEDs? Would I need additional transistors or anything? Could I use 2 of these to drive 10 rgb LEDs off a single microcontroller? Thanks for the help, I really appreciate it!

 

This is a pretty cool device. Mikey likes!

Yes. Each RGB LED needs 3 outputs, so 5 of these require 15 outputs, and this thing has 16.

Nope. Each output is a PWM switched controlled current sink, so the LEDs wire in directly. See Figure 10 of the spec sheet.

DO pay attention to the DISSIPATION RATINGS on sheet 4. Even the SOIC is rated for 1.2 watts, that's a lot. The QFN package is better at 3 watts but that will need a good thermal pad underneath, basically one huge pad with vias to the other side to help spread the heat generated. Without this pad it may be comparable to the SOIC package.

When you pick some LEDs stop back and we can check how much power they will dump into the package. It's basically (your Vcc - the LED diode drop) times the current you drive them at, sum for each and every LED.

If the power gets excessive then some external resistors can help (a lot!).

Each device has 4 pins to set the I2C address, so you could add 16 of these things on a single I2C bus. And since you could conceivable have several I2C buses off the same micro you can keep stacking these things up.

Hey I just got here!

 

Thanks again! Great stuff!

Found these, might choose something else, but heard they're pretty good:
http://www.superbrightleds.com/moreinfo/through-hole/rl5-rgb-diffused-tricolor-led/776/

2*.02*3*5=.6W so I should be fine. Might implement this, not sure it will be cost effective, but does make things simple!