7-segment display driver

[pcar]

I want to design a single digit, 7-segment display circuit and was wondering about the latest state-of-the-art method using the fewest components for best longevity. Electronics isn't my primary b.g., but am willing to climb the learning curve. Product will be used in adverse vibrating conditions. Will also pot the components as well. There are several BCD decoders on the market from which to choose.

Since this is a low-volume item, I'd like to reduce the amount of production hand soldering. Reduced components also increases circuit reliability, yes? The standby 4511 IC requires a group of resistors on both sides of the chip. 74LS47 only needs a group on the display side. Anyone use CA3160 or recommend others? Some are more expensive than others, but the up-front cost might be offset by reduced labor to assemble the board, not to mention fewer components to go south. Pros and cons of one over the other? I'm aware of matching the proper common anode/cathode LED display to the IC.

I looked at LCD displays, but I think LEDs might provide better visual perception. VFDs (vacuum flourescent displays) are nice and bright, but I haven't been able to locate a single digit unit; most are 2 digits or more.

In addition, any thoughts on an appropriate harness/connector-type for these conditions? Mil-spec?

Thanks for your patience.

 

[Skogsgurra]

Single digit? I would use a cheap micro for that. Multiplexing the segments and using one resistor in the common anode or cathode. That would leave with one resistor, one 7-segment display and a micro. Use one with internal clock and reset circuitry. You can put the rest of the functionality (counting, decoding, whatever) in the micro as well.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[jimkirk]

I've got a few old 7 segment displays kicking around. Apply 5 volts and ground, a 4 TTL input bits, and the decoding is built in. One component, maybe a bypass cap.

TI made the TIL306 and TIL307 (depending on where the decimal point was). Try a Google search. Since it's low volume, try one of the various rare and obsoleted parts distributers. I think HP made something similar, before Agilent split off.