Led Matrix

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
  • TPIC6595 8-Bit Power shifting register (250mA continious current per channel)
  • TPIC6C595, TPIC6B595, TPIC6A596 all simmilar to the above, ALL switch to ground
  • TPS1120 Dual P-channel Enhancemenent-Mode MOSFET
• On Semi
  • Latches they all suck 24mA current ist the maximum they can give
  • MOSFETs cheap thats cool
  • Shifting Registers they all suck 6mA max...

FPGA LED Matrix Controller

an FPGA producing the correct signals to drive