Hmm an opamp comparator.. when not limiting, nice. You need an opamp that goes to the positive rail. What are you going to use?
George H.
Hmm an opamp comparator.. when not limiting, nice. You need an opamp that goes to the positive rail. What are you going to use?
George H.
Win, I once worked through foldback limiting with the sorta bog standard npn/ pnp current limit circuit. (See AoE 3 pg 694 for those reading along at home.) Do you see some easy way to add that to JL's opamp circuit? ...
Thanks, George H.
Add one resistor, from output to opamp -.
My load - a 50 ohm pulse generator - is such that I don't need foldback; limiter output voltage can't go all the way to ground. I do want high peak pulse current, and the output cap does that.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
My latest fave is OPA171. RRIO, 3 MHz, 36 volts.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
OK thanks.
GH
torsdag den 21. februar 2019 kl. 05.11.05 UTC+1 skrev John Larkin:
Does the PMOS have to take 24V gate-to-source? Bipolar pass element with a base current resistor is the easy fix. Diodes/resistors would protect the gate, but part count is high. Comparator instead of op amp has a two-resistor drive solution.
LP2951 might be the best overall, if your current limit doesn't need accuracy.
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