Edit - I found a 24v pump as an alternative to the 220v pump. Discussion of 220v below can be ignored.
I want to produce a 220V square wave at 50hz with a varying duty cycle from 0% to 50%.
I feel it would be a good idea to have a hardware failsafe in case the arduino ever loses it's way and produces a constant Ground output or any similar out of spec output. I have produced the following circuit that appears to prevent any pulse longer than about 15mS in simulation.
(PDF is a clearer picture)
I don't think the circuit looks "elegant" and I would like to know if there is a low part count and cheap
alternative that would do the job better.
Logic-mosfet-drive.pdf (41.4 KB)