I've got a Maxim7219 controlling an 8x8 grid of LEDs. But I'm not able to get the LEDs bright enough.
Rather than powering the LEDs directly with the 7219's output-current, I'd like to implement the transistor circuit described here:http://www.maxim-ic.com/app-notes/index.mvp/id/1196
I think I'm able to use the Arduino's 5V supply voltage to light my LEDs, so I'm aiming to use the 'Figure 1' circuit for the DIG pins.
Can anyone help me determine which microchips to use for these transistors? I am quite new to working with transistors and am confused.
If I read this correctly, it looks like I need to use two different chips: An array of FETs on the DIG pins, and an array of NPNs on the SEG pins.
Some of the chips I've been looking at include:
But I'm really not qualified to tell these chips apart or understand precisely what they do.
Any guidance would be greatly appreciated!!
(I've also heard it suggested that this Maxim circuit may not be the best way to do this. If anyone knows a simpler circuit that would work, then please share!)