I am curious about how it would work to go: uC -> Photocoupler -> ULN2003 or similar. what does VI(on) ON-state input voltage mean in the spec sheet? the ULN2003 has a max of ~3v, but it can be driven from a 5v uC. What does this all mean?
Hi, I doubt it when You say, "you can omit connecting the suppressor diodes common pin when not using indictve loads". I have done exactly that just because of couriosity on my latest clock build. It was on a high side driver. Anyway. IF the diodes could be pulled out of the circuit that would work. By not connecting the common pin to Vcc it makes an OR-gate out ouf the INTERNAL diodes. Watch the multiplexed outputs simultaniously altering when done on a clock. The number digits start blinking at the frequency of the seconds LED, fed through the same chip.
Hi, see my U125D based clock. Initially it had used an integrate high side driver. The UTC 62783 is suffered from not fully shutting off the unused digits on a multiplexed clock. This results in ghosting on the LED displays. The Toshiba IC TBD62783AP is said not being suffered from this bad behaviour But I had none on hand. I replaced the 62783, a counterpart of the well known ULN2803, with a number of discrete transistor drivers. @@LewisLoflin Works much better.
