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Old 21st Jul 2020, 3:16 pm   #50
dave cox
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Join Date: Jan 2009
Location: Bristol, UK.
Posts: 2,059
Default Re: High voltage regulator circuit.

Andy, IIRC the TL431 is 2.5V without any resistors!
But yes, an LED would work and adjust the R3 a bit on the other side, it will have the same voltage across it.
I choose R6 to balance the current in the 2 legs of the LTP Q5/6 but its not critical.

I specified D2 at 30V but 24 will be fine. Monitor it in any case, it probably wont be that stable but it should not matter too much !

Yea, if the output voltage goes up too much, Q5 turns off, Q6 on then Q4 on (throught Q2) pulling the mosfets gate down by pulling current through R7.
Note, current can also be pulled through R7 by Q7 if the load is getting too much current.

Good luck Andy !

dc

Last edited by dave cox; 21st Jul 2020 at 3:27 pm.
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