I've got an old welder that uses two SCRs for current control. I'm trying to re-engineer the electronics for the scr control, I was looking at the 555 timer for this but then I learned about the TCA785. Anybody have any experience with this? Are there other ICs out there that might be a better choice? The two SCRs control 15 volts each and are rated for up to 110 amps. I can't find a datasheet for the SCRs but my calculations show that gate current needs to be as low as 20 ma, but a little higher would probably be desireable. I can provide a drawing of what I have if need be.

 

http://www.datasheetcatalog.com/datasheets_pdf/T/C/A/7/TCA785.shtml