LAPLACE

Hello Josef,

Please advise as to what simulator you are using.  

Thank you, 

~Leonard 

PSpice for TI

17.4-2020 S2006 Windows SPB 64-bit

Hello Josef,

Could you please archive and share your project with us? You can see archiving instructions here: e2e.ti.com/.../faq-pspice-for-ti-how-do-i-share-pspice-for-ti-projects

Thank you,

Jackie

OK, ZIP is ready - how to upload it???

test-coil-with-variable-Q-2021-07-21T10-50.zip

sorry.. got it!

I reduced the project to the most important parts. The coilcraft coil is a variable resistance coil. In the circuit I have a fixed inductance L1 and a fixed capacitance C1, which form an oscillating circuit with a resonance frequency of around 600kHz. Controlled by the variable R01, either the resistor R52 with a fixed value of 60Ω or the variable resistor G1, which also has 60Ω at 600kHz, is used. Its resistance value can be displayed in the output window using the additional trace V(R53:1, OUT)/I(R52).

The transmission curve for the resonant circuit with resistor R52 is correct, bandwidth approx. 28 kHz*. The curve for the variable resistance is wrong, bandwidth less than 0.1kHz, i.e. it is practically calculated with 0Ω instead of 60Ω!

Z=2*pi*600k*333µ=1255Ω, B(3dB)=600k*R/Z=600k*60/1255=28.7k

Thank you Josef. Please give me some time to look at your file. I will let you know my findings.

I guess / is it possible that XFORM = 1/s is behaving like an Inductor / capacitor ? Hence the difference in resonance frequency?

THAT'S IT! Replace XFORM = 1 / (s/62830) by XFORM = ABS(1 / (s/62830)) to get a REAL (not imaginary) value...

BUT: Why are the coilcraft models not using ABS???coilcraft.lib

Hello Josef,

Does that resolve the issue you are facing? As far as the model creation, I cannot comment on the models written by other parties.

Thank you,

Jackie

> Does that resolve the issue you are facing? 

definitely! Maybe there is a difference in handling between original and imported models, an between parameters in the GLAPLACE device which ca be placed in the circuit diagram and the GLAPLACE function. For the moment, I will model "real" coils as in the project above, which gives correct results with the ABS() function.

Thanks!