madsci1016:
This library is great, tested and will be used for my girlfriend's project.But, has anyone brought out the point that using regular 74HC595 shift register is actually a bad design as you are forcing it to drive harder then it's rated for?
Yes, each IO is rated for 20mA, but supply/GND current is only rated to 70 mA. All outputs 'on' would be 160 mA with 20mA LEDs. 160 > 70
I suggest a TLC5916 instead as it's rated to drive LEDS like this and it has built in Constant Current driver, so you don't need to add resistors in series with each LED.
You are right about the supply current rating. I had not even noticed it. The 595 do not get hot and seem to have no problem driving the LED's, but I am indeed exceeding the datasheet specs.