Reduce inrush current LTspice simulation

[rakeshm55]

I was trying to simulate inrush current for a battery powered product. Battery 28.8V li ion battery pack (10A continuous current supported...Pulse current of 18A)

I use a push button controller to implement Power ON/OFF....Also  a reverse voltage protection circuit ....

I plan to have following sequence for input protection....

Battery --->PTC ---> Transorb/MOV ----> common mode choke ----> reverse voltage protection ---> ON off controller

For the purpose of simulation I have skipped ist three components ....
On turn ON I can observe an inrush current of about 160A in simuation.... I will like to reduce is ..... Can the above circuit rearranged for soft start??
Any techniques to reduce start up current...

My understanding is I should keep inrush current less that pulse current of battery ... is it correct??

PLease advice on methods to reduce inrush current ....

[MiDi]

Inrush current limiting is achived by series resistance before caps, advanced would be ntc.
Keep in mind that battery, connectors, traces/wires, components in series will all add their series resistance and the cap has esr that adds too - this is not implicitly given in simulation.

As you have already a mosfet for reverse protection, you could go for one with the appropriate on resistance.

Quite not shure what value is added by the mov and the common mode choke when only battery powered.

[rakeshm55]

Can I add in some series resistance (say 10Ohms) during initial turn on??

Then once the Capacitors charge to a certain voltage level say 20-22V (Use TL431) I bypass using a pmos...

On googling i could not find any literature or standard technique on this --- I have seen delayed turn on but not voltage sense based Any inherent drawbacks for this??

What should be wattage needed for  resistor?? say I use a 10 Ohms 0.125W resistor. 100ms An  average current of 1A flows. Will the resistor sustain shuch pulse loads??

[MiDi]

No problem to add 10Ohms, that would give max 3A @30V.
As a rule of thumb resistors can withstand 10x rated power @room temp for very short time without degrading that much.
But that depends on the resistor-type, the max temperature for resistive material (not the resistor incl. case) and its thermal capacitance.
In general the smaller, the less capability of short term overload.

For bypassing after inrush current a pmos could fit, if a few 100mV dropout are suitable, a pnp would do it as well.
You have to provide appropriate driving circuit for bypass (second inrush).