Driving larger alphanumeric led digits

Using Arduino LEDs and Multiplexing
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Hi all,

I'm looking to build a little project with four alphanumeric displays from kingbright:

http://www.kingbrightusa.com/product.asp?catalog_name=LED&product_id=PSC23-11EWA

Here's my challenge: half of the segments run at less current in each display. The displays also have a common-cathode for all 16 segments (decimal not necessary for my project).

So I was thinking to use something like two MAX7219s or two MBI5026s, one for the segments that want 30mA, the other for the ones that want 60mA.

After a lot of research, my head is spinning and I'm concerned I can't make it work because of the mix of common cathode, as well as well as the heterogeneousness of currents that are needed within each character.

Any IC suggestions anyone could offer would be very appreciated. Not afraid of datasheets :slight_smile:

Thanks for your thoughts and suggestions in advance.

C

edit the link was to the common-anode product, not the common-cathode. Here is the datasheet for the correct part:

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Those look like just common anode to me.
Sink current from the segments with TPIC6B595, use 2 per chip, current limit resistors as needed.
I offer this board with up to 12 chips, can drive up to 6 digits for you.
http://www.crossroadsfencing.com/BobuinoRev17/

768×843 255 KB

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Hi, and thanks for the advice. Great board!

I have used the TPIC6x595 in the past and liked them quite a bit. My question is then, would I then need to put a resistor on every segment of every digit 16x4=64 resistors?

I am hoping to come up with something a little quicker to assemble.

Thanks again for the help!

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Thanks. It does really nice driving LED strips with built in current limit resistors.
Yes you would.
The alternate is 1 resistor per common anode, and only turning on 1 segment at a time, resulting in a much dimmer display.

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