LM3488: Problem for PSpice for TI simulation based on TIDA-010057

Hello Satoshi,

Thanks for reaching out to us via e2e.

When I load the project that you have attached in my PSpice for TI version 2021.1, I get the following result for the transient analysis:

Where exactly do you get your problem in ?

Thanks,
Harry

Hi harry,

Thank you for confirming,

I got the same simulation results, it was not converge and ±Vout are not become ±80V.

Is there uncorrectable point on schematic?

Best regards,

Satoshi

Hello Satoshi,

It seems that in my understanding the word "converge" has a different meaning than in yours.

In my understanding:
If a PSpice model does not converge, I will get an error message and I will not see the transient simulation results at all.

Obviously you mean something different when you say "it does not converge".

Can you please explain?

As per the level of the output voltage:

I can see that in your schematic you are using different values for the voltage divider compared to those in the TIDA-010057 schematic.

The output voltage is calculated in the following way: 

TIDA-010057 schematic:
VOUT = ( 1 + R42 / R45 )  x  1.26 V
VOUT = ( 1 + 294k / 4.7k ) x 1.26 V  =  80.08V

Your schematic:
VOUT = ( 1 + R11 / R6 )  x  1.26 V
VOUT = ( 1 + 330k / 7.5k ) x 1.26 V  =  56.7 V

So, with your voltage divider resistor values you will not reach 80 V.

What are R20 and V2 meant for?

Thanks,
Harry

Hi Harry,

I answer your question and update information below;

・Converge is the same means.

　Schematic is based on TIDA-010057, but simulation results is abnormal.

・Sorry, feedback divider value is mistaken.

・R20 and V2 meant for DC injection and adjust Vout, to prepare Vout change and test.

・Improved schematic is attached below, but simulation results is not steady ±80V.

　（Once Vout rise to about ±60V, but after Vout gentry decrease）

　If there any improve point, please let me know.

20220329_lm3488.zip

Best regards,

Satoshi

Hello Satoshi,

I will have a look at it next week.

In the meantime, can you please clarify the following:

One one hand you say that in your case the simulation does not converge,
which means that you cannot get any transient simulation results at all.
The window that I have sent would not even open in that case.

On the other hand you say that your results are the same as in the picture I have sent / they are abnormal / not steady,
which means that you can see the content.
So it does actually converge.

Which one is the case?
Do you see the diagrams in the transient simulation window or not?

If you can see them, what do you mean when you say "does not converge"?
Do you mean that the results are not stable or not as expected?

Thanks,
Harry

Hi Harry

Thank you for support,

I answer your question below,

・I can see the diagrams in the transient simulation window

・The mean of converge is "not as expected".

Best regards,

Satoshi