For the LED Matrix we want to build on the CCCamp2007 we decided to design our own LEDMatrix Controller/Driver setup. It will consist of two parts.
LED Matrix Driver Boards
Our Matrix should have a resolution of 48x72 pixels. So there will be 48 rows and 72 columns. The basic building block of our ledmatrix will consist of an 8x72 pixel module (or 8x48 if 72 is too big for a decent refresh rate).
So how is such basic building block connected? The cathode (GND) pins of all LEDs in each of the 8 rows are connected to each other. These 8 rows are each connected to a powermosfet and are driven to ground one at a time (so the matrix is 8times multiplexed).
Likewise all the annode (+) pins of all LEDS in a column are connected together and are driven by a constant currentsource (I could not find a shifting register that can sourcer more than 20mA this suxx)
chips that might be usefull for this
- Texas Instruments
- On Semi
FPGA LED Matrix Controller
an FPGA producing the correct signals to drive