Simulate the TI's Demo board PMP7188 in LTspice

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Basically,it can work.
But I discover that the value of Vin is digger than 36(typ Vin ESD) in the beginning.


Theoretically, Vin should be clamped between 30~40.
It is impossible that Vin>40.
Is it a error of LTspice???

plz help me with this problem.m(_ _)m

View attachment PMP7188.rar
 

Hi,

in the given picture I see the "5mA" condition. Did you take care about this?
How do you limit this current?

Klaus
 

KlausST

Sorry!
I didn't notice it!

I don't know what it mean.
I use resistor(R1&R2) to limit the current.
 

Due to missing components, the circuit can't be simulated. If you post a simulation circuit, you should add all files that are not contained in a recent LTspice distribution.

I might be either a model fault (Z-diode missing or inappropriately modeled) or a LTSpice problem.

5 mA is a maximum rating for continuous current. The Z-diode should still have a clamping effect at higher currents.

- - - Updated - - -

I reviewed your circuit a second time. Looks like LM5021 misses a ground pin.

- - - Updated - - -

Second comment. I see that the LM5021 model uses global ground node 0. Should work, bad practice though.

But there's no Z-diode model in the subcircuit. You may want to add it externally.
 
FvM
Sorry, it's my false that I didn't check the files.
This is a new files I have checked.
View attachment PMP7188.rar

the LM5021 model has only just 7 pins.
I will simulated in TINA-TI again.
If I have any information or solution, I will reply here.

In order to simulate optocoupler, I use Diodes and behavioral current sources as shown below.
 
Last edited:

Still missing symbols



If you post a simulation circuit, you should add all files that are not contained in a recent LTspice distribution.
Click to expand...
Means, you unpack the archive, open the *.asc file and start the simulation with a standard Ltspice version.
 

Besides the missing Z-diode in LM5021 model, which can be easily added, what's your particular question?
 

My question is:
Because Cvin(C7) should be shorted to GND, the Vin should be close to 0 in the beginning.
The Z-diode shouldn't be a major cause this result.(Maybe I'm wrong)
 

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