View Single Post
Old 2nd Aug 2020, 9:56 pm   #89
dave cox
Nonode
 
dave cox's Avatar
 
Join Date: Jan 2009
Location: Bristol, UK.
Posts: 2,059
Default Re: High voltage regulator circuit.

MJE5852G is a possible, but its a bit hefty/expensive (for what you need) and it still running not a million miles from its secondary breakdown limit.

Maybe the one you have with a few zeners is the best option after all. Usually, with a current source you would not want to cripple its compliance (*) with a string of zeners but in this case it is predictably dropping down from the supply rail to the 24V rail, so as long as there is enough compliance left to soak up any supply voltage fluctuation, it doesn't matter.

Refugee's point about a separate supply rail is sound. If that WERE available we could power the ref and other electronics from it and then there is no issue with heat. If its available, of course

dc

(*) Compliance meaning its ability to swing the output voltage in order to get to the right current. The LTSpice ones will go to multi-mega volts but in the real word they are restricted by the supplied voltage less a 'bit' to operate. If you add zeners then that 'bit' becomes a 'lot'
dave cox is offline