I represent a simple current limiter using a JFET and a tiny shunt resistance Rs.

Per Siliconix App Note AN103 (1997-03-10), the value of Rs to limit current to Imax is approximately -VTO/Imax*(1-sqrt(Imax/Idss)). Idss is I(Vgs=0), which is 2-4 times BETA when there is any significant current limiting happening. "For best regulation, [Imax] must be considerably less than Idss."

So, if Idss=2*Imax and BETA=Idss/2, set BETA=Imax. But I set it a bit higher than that, 2*Imax.

I introduce the following alterable values into the circuit in which I am included:

slope: A channel-length modulation parameter for the JFET that reduces how drastic the current limiting eventually gets. Basically, a slope limiter for the voltage vs. current curve after limiting starts.
shunt: The shunt resistance.

Instance Variable	Imax	Maximum current, the point where I really start dissipating power to limit amperage.
Method	setup	Conventional current flow is from my pos (more positive) terminal into me and then out my neg (more negative) terminal.

Inherited from NodeStuff (via Include):

Instance Variable	shunts	A dict of current sensing V elements with the pairs of nodes they connect.
Class Variable	debug	A `Bag` that gets set `True` for all instances to log info about each `setup` call.
Class Method	autoName	Undocumented
Method	setupResults	Undocumented
Method	fill	Undocumented
Method	nodeCheck	Call with the circuit building tool f and a sequence of nodes provided to this `Include` or `Subcircuit`.
Method	rawNetlist	Get lines of a raw netlist from a search hierarchy of possible sources.
Method	shunt	Call to insert a current-measuring shunt and add an entry to my `Elements` baton's dict of shunts.
Method	raw	See `Elements.raw`.
Method	iNode	See `Elements.iNode`.
Method	ground	See `Elements.ground`.
Method	sca	See `Elements.sca`.
Method	sca6	See `Elements.sca6`.
Class Method	_libDir	Undocumented
Method	_strippedLines	Undocumented
Method	_call_setup	Calls my `setup` method (almost always your override of that method, actually) and processes any return value.

Inherited from NodeStuff (via Include):

Instance Variable	shunts	A dict of current sensing V elements with the pairs of nodes they connect.
Class Variable	debug	A `Bag` that gets set `True` for all instances to log info about each `setup` call.
Class Method	autoName	Undocumented
Method	setupResults	Undocumented
Method	fill	Undocumented
Method	nodeCheck	Call with the circuit building tool f and a sequence of nodes provided to this `Include` or `Subcircuit`.
Method	rawNetlist	Get lines of a raw netlist from a search hierarchy of possible sources.
Method	shunt	Call to insert a current-measuring shunt and add an entry to my `Elements` baton's dict of shunts.
Method	raw	See `Elements.raw`.
Method	iNode	See `Elements.iNode`.
Method	ground	See `Elements.ground`.
Method	sca	See `Elements.sca`.
Method	sca6	See `Elements.sca6`.
Class Method	_libDir	Undocumented
Method	_strippedLines	Undocumented
Method	_call_setup	Calls my `setup` method (almost always your override of that method, actually) and processes any return value.

Imax =

Maximum current, the point where I really start dissipating power to limit amperage.

def setup(self, f, pos, neg):

overrides pingspice.circuit.netlist.Include.setup

Conventional current flow is from my pos (more positive) terminal into me and then out my neg (more negative) terminal.

API Documentation for pingspice, generated by pydoctor at 2021-09-18 08:41:11.

pingspice.examples.current-limit.CurrentLimiter(Include) class documentation

`pingspice.examples.current-limit.CurrentLimiter(Include)` class documentation