Alan8947
Full Member level 4
I was simply assuming that the solid state relays will never be turned on while a larger output voltage is present by working of the protection circuit. If this happens though with low impedance load, there can be a much higher energy dissipated due to the relative slow turn on and SOA exceedance is more likely.
Hi FvM
Lowering the R4 from 5.1K to 2.5K is the best I can do. The recommended current through the diode is 10mA. With 2.5K and +33V supply, assume voltage drop across the R4 is 30V, that's 12mA already. Do you have any better Photovoltiac isolator better than the ASR-V621, I can't find any? OR do you have a better circuit for SS relay for this purpose ( linear and below 2mohm on resistance).
Mechanical relay doesn't even come close to this good.
Thanks