I'm just powering opamps, so 50 mV of load regulation doesn't matter here.
My sim shows 30 mv drop when the 10 mA current load step kicks in. The thing that wrecks regulation isn't the zener, it's R1, the current-limit resistor. That 30 mV step drops to 5 mV if R1 is changed to 1 ohm.
What's annoying, in such a simple circuit, is that LT Spice will go compute-bound randomly, like when a part value is changed. The usual fix is to change the minimum time step from something arbitrary like 500 ns to 600 ns. Or back.
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John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com
Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators
Would be nice if there was a way to have the lib file show up in the parts list instead of using a directive to include the .lib maybe there is and I am just not seeing it.
Yes. The problem with your circuit was that the charge pump wouldn't work, which I pointed out and you subsequently realized. Your assumed Vrect waveform won't be available in a real-life offline power supply.
You posted two unsuccessful circuits to solve the startup problem, and then declared that your third one works. But you never posted that one. Why not?
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John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com
Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators
That's with a MMBZ5232BT (5.6V nominal) zener. Zener current 0.35mA to 1.05mA over same input voltage range.
What's annoying, in such a simple circuit, is that LT Spice will go compute-bound randomly, like when a part value is changed. The usual fix is to change the minimum time step from something arbitrary like 500 ns to 600 ns. Or back.
All Spice does that. This particular example was happier at 10us than 1us.
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"For a successful technology, reality must take precedence
over public relations, for nature cannot be fooled."
(Richard Feynman)
Most of the older Tek sampling scopes used an avalanche transistor to generate the sampling impulses, directly or through an SRD. The ones still around usually work, after trillions of avalanche events.
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John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com
Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators
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Regardless, that's a dangerous protocol to follow because whatever you
"dump" into any LTspice folders over which Linear Tech exercises
control can be deleted at their convenience or, as a matter of course,
during synchronization.
A much better approach is to upload all of the files to a single
directory, somewhere, and then have your readers download them all
into a single folder.
The beauty in that is that all of the data needed to run that sim will
be local to that file, making it truly portable as long as the circuit
list *.asc file is associated with LTspice.
Helmut has posted the procedure over and over again for those of us
who are slow to catch on.
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