ICM7228B IC Driven One to Eight Seven-Segment LED Display

Using a specialized IC to control a LED display is probably the best way to go. The ICM7228B IC is only about $4 (US) from Questlink.com. Using the ICM7228B driver, you do not have to have a microprocessor or microcontroller constantly updating the display (like this more simple design). The driver has a built-in 8 byte RAM to write your data into from a processor or controller. The ICM7228B takes care of the rest. It can also be set up to decode and display hexadecimal (0-F), CODE B (0-9), or you can control each individual segment. In order to interface to this circuit you will have to read the data sheet for the ICM7228 (download at Questlink.com). Enjoy.

Component Notes

U1: ICM7228B 8-digit LED display driver

LED1-8: Common-Cathode 7-seg. LED displays (low to medium current)

Example PCB

I have found this component layout to take up the least amount of Printed Circuit Board space. Notice that I did not use "through-hole" pads for most of the components. This is because I used IC sockets for the displays and for the ICM7228B IC. With IC sockets, there are no leads exposed on the top side of the board, therefore, it is not possible to solder the ICs on the top side (only the bottom). I did this so that I could easily remove these components, because as you probably know, there somewhat expensive. Blue tracks represent the bottom layer and red the top. Enjoy.