This is a 7x5 LED dot-matrix with driving circuit. LEDs are connected serially along both rows and columns.
LED0 ~ LED5( the column lines) are connected to the data signals through a 74HC574 and DRV0 ~ DRV6(the row lines) are used as the line driving signals through a 2003A. This circuit uses 1/7 duty driving method that turns on only a row line at a time slice.
So it turns on a line after a line from DRV0 to DRV6 and it starts from DRV0 again repeatedly. As you know, it’s so fast we can’t recognize the sequence and it looks like everything is turned on all together.
The 74HC574 is octal 3-state non-inverting D Flip-Flop. It has 8 channels, but only 6 channels are used in this application.
The 2003A is a 7-channel darlington sink driver(or transistor array). It can drive up to 600mA per channel, so it light up about 30 LEDs serially. It comes from many manufacturers with other different names. You can use TD62003, ULN2003, ULQ2003 or ILN2003 as the same usage.
Here is the picture of a heart image displayed on this LED dot-matrix.
This is the schematic of simple 7x5 dot-matrix with driving circuit.
