Big LED displays

Archiver

Dear List,

I am trying to make a four digit LED display using four 4" displays made by
Ligitek (common cathode). They require between 12 to 14 volts total to be
driven. I am using the Maxim 7219 seven segment LED driver... the problem
is of course that the Maxim chip cannot deliver that kind of voltage. I am
a bit unsure how to bridge the two... I need to bridge both the segment pins
and the digit pins of the chip to the display. How? I am assuming the
segment pins are positive and the digit pins are negative... The Maxim
chip's datasheet has a diagram that claims to explain how to do this but it
seemed to never leave the 5 volt realm.

Thanks in advance

Paul

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Paul Ramirez Jonas
email prjnyc@m...

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Archiver

> I am trying to make a four digit LED display using four 4" displays made
by
> Ligitek (common cathode). They require between 12 to 14 volts...

> I am using the Maxim 7219 seven segment LED driver... the problem
> is of course that the Maxim chip cannot deliver that kind of voltage.

Paul,

While not slated to be released until early next week, I'll mention this
just a bit early since you asked: The EDE707 Octal Seven-Segment LED Display
Decoder is now available for shipping. This 28 pin addition to our EDExx IC
Family should be just what you are looking for; its outputs drive
inexpensive 2N2222 NPN transistors, so the voltage you're using will pose no
problems.

Features include a full Hex character set (0123456789AbCdEF), counter
functionality, leading zero blanking, and lamp test. Interface is via a
four-bit bus with latch signal.

A PDF datasheet is available for download at our website:
http://www.elabinc.com in the 'EDExx IC Family' section. Also, for a CD-ROM
containing our latest datasheets (Paul or anyone on the list), just e-mail
me your postal mailing address (off-list) to the address shown below.

Best of luck with the project!

Todd Peterson
E-Lab Digital Engineering, Inc.
(816) 257-9954 FAX: (816) 257-9945
toddp@e...

http://www.elabinc.com