Hello,

I am trying to drive an 8x8 RGB Common Cathode LED matrix. I am planning to use four 74HC595 shift registers. The problem is that I want to get the maximum brightness out of the LEDs but I do not know which IC to use between output of shift registers and LEDs.

I am using 5050 smd RGB LEDs

5060BRG4.pdf

I know that shift registers provide 20mA and 20mA is sufficient for the LEDs, however as 8x8 LED matrix is driven by one column at a time, the brightness is diminished by 8, so I need more current. (That's why in the datasheet of the LED there is a parameter called : "Peak pulsing current (1/8 duty f=1kHz) " I think )

The schematics of the driver circuit and the 8x8 matrix are :

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What should I use in the box with the question mark in the schematic of the driver circuit? I am planning to use UDN2981 for the anodes and ULN2803 for the cathodes of the LEDs. Would this configuration provide me maximum brightness? I would appreciate if you could help me.

Thanks.