TI LM25037 Not Running

QSPICE
1

I created a new model using the, “unencrypted PSpice Transient Model” from TI’s website, the model created just fine.
However, when I try and simulate with it I get the following error:
Fatal error: Error: no such function ‘sdt•x_osc1_vco•x1’
The problem occured while parsing the line:
** ESIN OSC1_VCO_SIN 0 VALUE {SIN(6.28318*(FCENTERV(TIME_A)+FRANGESDT(V(TABLE)))+PHASE*(3.14159/180))}**

I don’t know enough about the spice sintax to understand why I’m getting this error, any help would be
appreciated.

link to model

LM25037 Model Link

2

Open the model in text editor and edit SDT to DDT and try again.
Best regards

3

Pspice reference guide refer SDT as time integral of x
PSpice Reference Guide (upenn.edu)
image

The equivalent function in Qspice should be IDT

image
image956×37 2.04 KB

IDT should work in format idt(x), idx(x,y) or idx(x,y,z).
According to ivan comment, replace the line #611 with following to see if can work.

+Value {sin(6.28318*(Fcenter*V(time_a)+Frange*IDT(V(table)))+phase*(3.14159/180))}
1 Like
4

Thanks, that worked.
However, it’s running very slow, maybe i need to add some other .options, i’ll try that.

5

I made another part and changed SDT to IDT as you suggested, this also worked. But, the model is still very slow.
I still haven’t tried some .options yet.

6

Hi Guys-
I’m just now getting back to this design and I’m still having a lot of trouble getting the LM25037 to run.
As soon as i get one gate drive pulse it locks up, i tried setting a few initial conditions, limiting the maxstep but nothing is working. I have a feeling its all related to some with the LM25037 model, maybe there is another issue like KSKelvin pointed out.

Push_Pull 5June24.qsch (108.6 KB)
LM25037_TRANS_3.txt (30.1 KB)

7

Edit > Preferences : Disable “Fast (less accurate) Math”.
However, it is highly inefficient for Qspice to run the LM25037 Pspice model. After running the simulation for a few minutes, the performance significantly deteriorates, and the .qraw file quickly becomes excessively large due to the generation of numerous simulation data.

8

That’s what i was afraid of, thanks for looking at it.

9

Hi,

I added a buffer or “E” with gain=1 at the LM25037 FB input. It’s in burst mode but seems to work well. ( According to the circuit design, the target level of V(out) is approximately 1kV. )

I’m not exactly sure why a buffer is needed at the FB input, but without it, the V(out) didn’t converge to the expected 1kV.

image
image1912×1107 145 KB

Push_Pull 5June24.qsch (86.9 KB)

10

Good call, EL34.
The return for V(FB) was different from X2, it must have tripped up the netlist somehow.
Thanks!