Hi, I have now built a circuit based on the TPIC6B595 to drive the common cathode displays. The first attempt worked in that it displayed the numbers correctly but the resistors goot too hot when the segments were not on !!! Each digit, fully illuminated, drew about 125mA (each segment draws about 15mA when on) - when all the segments were off the current jumped right up to about 1.5A - lots of heat coming off those 100R resistors.
The next attempt was very similar but using the TPIC6B595 to switch 2N7000G mosfets - I guess the theory is right but something is wrong in my circuit because it just doesn't want to play.
I have seen some circuits with a 100nf ceramic cap across the TPIC6B595 (connected to VCC & GND?).... decoupling? and a resistor on the common cathode/anode line on the digits - I don't know if adding either of these will help?
This is what I have done.....
