IN-RUSH CURRENT LIMITING: PREDICTING WITH LTSPICE

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scelbit

Joined Jul 24, 2019
4
I have a somewhat standard in-rush current limiter. I can see intuitively how it works but am trying to get a value for the reduced inrush. LTSPICE, which is what I am using, models the steady state current fine with limited output capacitance and a load of 4.5ohms. When I add in the capacitance and the limiter the output voltage drops to 0v and 0 current which is fine except I should be drawing current. Does anyone have an inrush current circuit that works or can anyone tell me why LTSPICE can't predict the inrush? The load is a microprocessor circuit not a motor.
 

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ericgibbs

Joined Jan 29, 2010
14,648
hi s,
Please add your MOS model. ,lib
BTW: in tran you have Ignore initial also not set the Start from 0,
Try changing these and rerun the sim

E
 
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