LM3481: Simulation model clarification

Hi Archie,

thank you for supporting the LM3481.

Can you help me to find the location of this line in question.

Which model, version are you using?

Which file is this in, which line number?

Best regards,

 Stefan

Hello Stefan,

This is the model he is using:
LM3481 Unencrypted PSpice Transient Model (Rev. D)

"Statements on lines 123 and 174 in the pspice Transient Model file, the statement on line 123 is not understood, how can the sine function on line 174 be implemented with circuits in pspice?"

Thank you.

Regard,
Archie A.

Hi Archie,

this is still a model and on some points it is better to put simplified more mathematical functions onto the model then the full and real implementation.
Otherwise simulation would not take hours but days.

(e.g In the design the sine would be a oscillator)

Best regards,

 Stefan

Hello Stefan,

Thanks for the information.

Cx would like to ask, what function is the statement on line 123? How to set parameters?

Regards,
Archie A.

Hi Archie,

i think in this case it is not a function but a parameter which is set above: PULSE=155n

I am not sure where and when you would like to set parameters but have you watched the videos for PSPice for TI:
PSpice® for TI: Introduction | TI.com Training Series

In one of them is explained on how to set parameters on the top level.

Best regards,

 Stefan

Thanks, Stefan.

Cx needs further clarification:

I still don't understand which statement, I think it is a power supply, but the setting parameters are not correct.

V_IFA FA FA_SD PULSE 0 0 0

The above statement, you think PULSE=155n, which statement is in the PSPICE diagram?

Regards,
Archie A.

Hi Archie,

see line 189:

X_U2_U788 U2_N16828837 U2_N16832334 rising_oneshot PARAMS: PULSE=155n

Best regards,

 Stefan

Hello Stefan,

Apology but customer has follow up:

V_IFA       FA    FA_SD    PULSE  0  0  0          How to implement this statement in PSPICE? Can you draw a circuit diagram?

Regards,
Archie A.

Hello ArTzy,

I am sorry, but I do not understand what exactly the problem is. Could you please explain what the customer is doing with the model and what exactly the problem is?

Best regards,
Brigitte

Hi Brigitte,

For example,

E_ABM166         N17033989 0 VALUE { IF(V(FA_SD_30uhigh)>0.5,0,2.7)    }     This statement is implemented using the following circuit.

How can the following two statements be implemented with circuits?

V_U2_IFA U2_FAINT FA PULSE 0 0 0
E_U2_VCO_SIN U2_VCO_SQ 0 VALUE { SIN(2*3.142*V(U2_N16819994)*TIME) }

Thank you.

Regards,
Archie A.

Hi Archie,

Thank you for your reply, please allow us sometime to get back to you on this.

Thank you 

BR,

Haroon

Hi Archie,

Thank you for the detailed description.
I assume the customer is trying to rebuild the initial internal schematic based on the netlist, correct?

We do not have a hierarchical model for LM3481 available, therefore I cannot check how the circuit originally looks like.
Based on the code itself, it looks to me like a Pulse function with initial current=0, pulsed current=0 and time delay=0, so no actual pulse is happening.

It might be a dummy source for testing purposes, but I am not completely sure what the actual function of this line is.

Best regards,
Niklas