LDO with current limit

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.

Reply to
George Herold
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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.

Reply to
George Herold

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.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

My latest fave is OPA171. RRIO, 3 MHz, 36 volts.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

OK thanks.

GH

Reply to
George Herold

torsdag den 21. februar 2019 kl. 05.11.05 UTC+1 skrev John Larkin:

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Reply to
Lasse Langwadt Christensen

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.

Reply to
whit3rd

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