Dwayne Reid wrote:
>
> >I am using a PIC16C84 to drive some 7 segment LED displays.  My problem is
> >that the LED's are those BIG (3 inch) ones and each segment needs 40mA.  I
> >was going to use a 2803 to drive them but with all 7 segments on, it looks
> >like the power was too high.
>
> Scott - are you going to multiplex the displays?  If not, 2803 (or its less
> expensive 7 wide brother 2003) will work just fine.  Each channel is good
> for a maximum of 500 mA, total package current is ok for 600 mA or so.  Be
> sure to take the aprox. 1.2 V saturation voltage when calculating your LED
> segment resistors.
>
> PS: I've been talking up TPIC6B595 power o/p shift registers for several
> months now.  Each channel is good for 150 mA and all channels can be used at
> full current without any concern.  You can drive multiple displays
> (non-multiplexed) using only 3 output pins on your pic (2 pins if you use a
> RC delay on the clk line to drive the latch pins.  My current project uses 3
> seperate 32 bit bidirectional serial chains using only 5 i/o pins.  My
> eeprom shares 2 of those lines and takes one more i/o for a total of 6 i/o
> pins for ALL of my digital inputs, outputs and configuration storage.
>
> Anyways, hope this helps.
>
> Dwayne
Use Current limiting resistors !!!!!!!!!!!!!
        saras