Hey guys, so soon ill get my hands on a flip dot display from an old bus, and i'm starting to think about the circuit. I'll multiplex the dots, and use and H bridge to change polarity with a bunch of 8 bit shift registers for the coulombs and rows. I started to think about power and got very confused. With the shift registers, the latch pin will only be enabled when all the bits are in place, the everything will turn on exactly at once. Thats a lot of current. For each dot i might need around 400 ma, and 4.5 volts, so i need to do them a couple at a time. I was going to put a transistor IC after the shift registers also. How should i go about this problem?
You said you were using a mutliplexed h-bridge to flip the dots. So I'd imagine you'll have a bunch of relays, or transistor equivalents, that will let you connect the h-bridge to the individual flip dots so you can pulse current thru them one at a time & flip them as needed?
Im not sure what you mean. I dont know yet how the H bridge would be connected to the system.
if i have shit registers connected to each row or coulomb, couldn't i just change the polarity there. Like for one coulomb I would make it 1, then for the row 0 to flip one way, then just switch to go the other? that would make it so no H birdge would be needed