Big 7 seg LED display

[sayzer]

While I was editing the concept, mat posted.

How is it now?

[mister_e]

Nope ! or i have some doubt...

[mat janssen]

The schena above is still not ok.
Her an example how it should work.

From Darrel:
Mat, the file caused an error in vBulletin due the the filename "div. voltages.GIF". Can you try again?

[shahidali55]

Thanks for your replies everyone..
Is there any logic level convertion IC that can do this???

Sayzer, your idea for the a,b,c,etc segments is using NPN transistors is what i had in mind.
If i feed the output of the pic to a 4011 (AND gate with its both inputs made 1 common),
and then give it to a PNP transistor, will it work???
I think the AND gate will do the level conversion, i'm not sure ? ! ?

[mat janssen]

Here another try for the diagram.

[keithdoxey]

Thanks for your replies everyone..
Is there any logic level convertion IC that can do this???

If i feed the output of the pic to a 4011 (AND gate with its both inputs made 1 common),
and then give it to a PNP transistor, will it work???
I think the AND gate will do the level conversion, i'm not sure ? ! ?

No. The 4011 will still be connected to the 5v supply so the PNP will always be driven as its base will not be allowed to go to 9.6v to turn off.

You could use a chip with open collector or open drain outputs. Another ULN2803 would do the trick but would occupy about the same space as the three resistors and NPN transistors it replaced.

[sayzer]

shahidali55,

As Keith said, you will most likey have to use two ULN type of drivers.

Thats seems to be the way.

Also, why not consider mat's schematic?

Or if you have limitations, why not try finding Big Led displays with 5V, if there is any?

[shahidali55]

Big displays of 5v are not available...
Thanks for the schematic Mat.
Will your circuit work for 12v displays also???