Big 7 seg LED display

[shahidali55]

Hi everyone,
I made a 4 digit LED clock using 4, 7segment common anode displays of 1 inch size.
Now i want to make a bigger one using 2.3inch displays.
But these 2.3 inch displays require more than 9.6v to function.
Since i am multiplexing the 4 displays, i need to control the 8 cathodes (which are in parallel) and the common anodes. But these anodes require 9.6 volts.
But the pic can supply only 5 volts. How should i make the circuit so that it supplies 9.6 volts to the displays???
Can anyone please help me?

Hardware :-
4 common anode 9.6v displays (2.3 inch)
pic16f84A

[mister_e]

Do a little search for Level Translator.

You will find some Transistor, CMOS, etc etc circuits for that.

[sayzer]

A concept as below could work, I think.

It is just a concept though. Can be modified for anode / cathode path.
You will need 8-transistors + 4 for the common ones.
ULN type of drivers could be handy here, but you need to make use of them with respect to anode/cathode issue.



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[mat janssen]

This will not work.
The transistor will work as a emittorfolower and the voltage on the emittor will not come over 4,3 volt.

[sayzer]

While I was editing the concept, mat posted.

How is it now?

[mister_e]

Nope ! or i have some doubt...