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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.
I am a newbee to embedded field first lesson: Keil does not support atmega and thus you are in the wrong place
the atmegas are discussed in a place named something like avrphreaks
Erik
Second lesson:
If the processor has 3.3V signaling, then most peripherial chips with 3.3V signal levels are compatible.
If the processor hsa 5V signaling, then most peripherial chips with 5V signal levels are compatible.
Third lesson:
It isn't enough to say that you need a LED driver IC. You also have to describe what problem you are going to solve. Are you going to drive a number of high-intensity LED for illumination? Or are you going to build a full-color 720x480 pixel LED TV? Or something in between?
http://www.avrfreaks.net/
Dear per westermark, thankyou for replying my message.I want to drive a LED display board that have 7 segment LEDs in both 2 inches and 1 inch length. 2 inch LEDs in upper part of the board and 1 inch LEDs on the lower side.There is a provision for digital clock,that would come in between 2 and 1 inch LEDs on the sides.Total LEDs constitutes 80 digits.I am using atmega16 to send signals to all these LEDs.I want to what type of driver that I should have to use that is compatible for Atmega16 to drive all these LEDs.Is this info is enough to you? kindly reply.
Read lesson 2 again.
If the LED driver has compatible signal levels, then it will be compatible.
In this case - since you have quite a lot of LEDs - you should look at either a multiplexed solution, but better a LED driver with shift-register and current control. Current control is extra important since I have to assume that there are multiple LED in each segment of these 7-segment digits. A multiplexed display requires that the individual diodes are very closely matched to make sure that they get an uniform intensity and that some LEDs are not burned to cinders.
Responder #1 - Erik Malund - is probably ready to supply a number of favourite driver chips, since working with display boards is what he does for a living.
What solutions have you looked at yourself?
I too have a thought of using shift register to drive all these in a multiplexed passion,tell me which IC(s) is better so that it could be used for shift register and multiplexer
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,
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.