Grumpy_Mike:
Asking a lot here for a forum answer, it is more like a chapter of a book you need.
single color LED
RGB LEDs
An RGB LED is just 3 LEDs, nothing special. Some (not all) have one connection common.
c)LED order (RGBRGBRGB, or RRRGGGBBB)
? - just depends on how you wire them up.
- Voltage limited (resistored)
- Current limited (LED driver)
No. 1) is not voltage limited, they are both current limited. Both attempt to produce a constant current in the LED. An active constant current output is what some, but not all, LED drivers have. Most that have constant current use a pull down constant current control because it is a lot cheaper to do this. This is what you call a common anode driver.
- current sink
- current source
Most drivers, even the ones that are not constant current use a current sink, again because it is easier / cheaper to do this. I know beginners don't like current sink but just get over it.
I would like to know more about LED driver chips,
So down load the data sheets and read all about them. There are many more than you mentioned. Go to a major distributor like Farnell, search on LED drivers and pick the ones you want to look at. The data sheet is available on line from them.
I assumed current source meant that the chips controls + voltage, and current sink meant controls the ground,
Yes if you want to think of it that way it will do as a working definition.
The MAX7219 also controls the multiplexing of a matrix in a way that many drivers do not.
So, for the scope of LEDs and microcontrollers, we can consider current source switching +5 on (or turn a pin high, or set to 1) all prettymuch the same thing, and current sinking switching to ground (or turn a pin low, or set to 0). also all prettymuch the same thing?
How would you group the driver chips? constant current (like TLC5940 ?), and not constant current (like shift registers ?) Or current sinking and current sourcing?
I suppose there is another category, where you use transistors to power columns or rows.
I looked over many datasheets, and there were perfectly good reasons to not use each and every one of them, but all that data is kinda mushed up into one big ball of not organized information. It would be nice to have a table that you could check off your needs, and get a list of viable solutions.
The max7219 is most suitable in multiplexing is exactly the kind of thing I would like to know about each of the driver chips mentioned, and not yet mentioned.
Does that chip control both source and sink, that sounds like another category all together.