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hello all, I am a newbee to embedded field.I need some good suggetions and details regarding LED driver-ic.I want to know which LED driver is suitable(or)compatible for atmega16-16pu mu-c and about the shift register IC that is used in a LED.please mention the full circuit details too.Thankyou.
Are you shifting (no pun intended) question now?
Are you switching the question from LED drive chips to standard shift registers? A normal shift register does not contain any logic to control the drive current. If you use a normal shift register (for example with 5V output) then you need to burn a significant percentage of the voltage over a series resistor just to handle the variances in the Vf of the individual diodes.
Multiplexing may work when you light individual diodes in an X/Y matrix. When you have multi-diode segments then you either do need a current-controlled driver, or you need to be able to drive the individual diodes in the segment one-by-one or you need that the diodes in the segment are in series and that you have high enough drive voltage so you still have a significant amount of voltage to burn over a series resistor.
Back to you again: Exactly what work have _you_ done. Have you at least once tried Google for LED driver chips and taken a closer look at some of the drivers? It is important that _you_ spend time learning exactly how driver chips works. The quickest way is to browse through the datasheets for 3-5 different chips. That would give you ideas. That would also give you the background knowledge to come back and ask specific questions about advantages of different concepts. Requesting that "the net" should do all your homework is not really a working solution. A 80-digit display board is expensive. You really own it to yourself and whoever chips (still no pun intended) in the money to make sure that _you_ learn how to drive diodes, and that _you_ know enough to be able to motivate why _you_ selected a specific chip - even if that driver chip was recommended on a web forum.
Why? It is _you_ who will have to explain why it doesn't work, or why the display burns out diodes, if you make an incorrect design.
I mentioned multi-LED display segments earlier. But I still don't know if there are one, two, three, four, ... diodes/segment. Or if the diodes have a common anode. Or if they have a common cathode. Or if they are in series... On the web, you may get an example of a perfect LED driver. But without the knowledge about how the LED segments are built, that LED driver may still be unusable - even if it is a golden-edition super-duper LED driver. Only you have the full information about the requirements. The only thing people on this - or other forums - can suggest is if the LED driver works with your, or any other, uC with a specific signal level on the I/O pins.
There are other important criteria too. How expensive is the driver - and does the cost matter, compared to the cost of the other parts in the project. Will the driver chip be available in your part of the world? How many driver chips do you nead, and what lead times can you accept for such a quantity? Are any second-sources available? Expected life-time of the product? Any mounting requirements? Most probably RoHS. ...
dear per, thanks for replying me.could I contact you further if I got any doubts in the future regarding embedded.reply.
SITI 2221A and smilar offerings from Allegro, Rohm and more,
Erik
STILL, this is the wrong place for ATmega references, where does Keil come in?.
If you post on any forum I read, I'm likely to respond.
But I don't do private consultancy on the net. I have enough work as it is.