LED Driver Overview
This section includes the design specifications for the LED driver circuit that I designed to use in my Retro Arcade cabinet.
The programmers of MAME have made it possible for the LEDs to flash during certain games to simulate the original arcade Player 1 and 2 flashing buttons. The Atari games like Asteroids and Tempest have this option, for example. I wanted a way to drive clear blue, high bright LEDs inserted in my Player 1 and 2 buttons to also flash.
I also wanted to drive accessory LEDs to light the trackball and coin door.
I chose to use a DG211BDJ analog switch to drive my LEDs directly from my I-PAC encoder. This can be accomplished by connecting the following. Note that you can also use the header plug on the I-PAC. I just feel it's a lot easier to use the screw terminals using the following configuration. You can go directly to http://www.ultimarc.com/ipac2.html for more details.
I have also tested the circuit with a DG211CJ, DG201CJ, DG411DJ, DG441DJ, and DG201BDJ. Just about any quad analog switch with the same pin configuration should work fine. Pin 12 is held high for compatibility with older analog switches.
My design will allow you to chose between using +5V or +12V from your computer. I chose to use +12V so I could drive up to three LEDs in series off of each output of my LED driver PCB. Adding up all the outputs and you can drive a total of 36 possible high bright LEDs! Using +5 will only allow you to drive one high bright LED per output.
Grab the specification sheet of the LED you want to use, plug the values into the resistor calculator, and start building!
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