LM5001 Simulation Model Not Working Webench

Brandon,

Simulation is supported for LM5001 Boost. It is not supported for LM5001 SEPIC. You can find this information here: webench.ti.com/.../devices

Best regards,

Thanks,
I simulated a boost using the deafult settings:

Vin: 12-36 V
Vout: 48 V
Iout: 0.1 A
Temp: 30 C

However, every time I try to simulate a bode plot I get an convergence error. Please help.

Brandon

Hi Brandon,

I apologize for this issue any inconvenience it has caused you.  I am currently looking into this issue, and will let you know once it has been resolved.

Regards,
Jonathan Arzadon
Applications Engineer
WEBENCH® Design Center
Texas Instruments

Jonathan,

Before the simulation was “fixed” we were able to simulate it once before we got that error. We remember seeing 0 degrees of phase margin in the example that was asked about.

 

With the fixed simulation the phase at unity gain is -105 degrees.  We interpret this to be 75 degrees of phase margin.  Do you agree?

 

Was the simulation fix to the phase reference of the model?  Were there other modifications?

Thanks,

Brandon

Hi Brandon,

Yes, you are right. The Phase Margin in this case is 75 degrees. We are in the process of unifying what we show to customers in Bode Plots. Currently what you see for some parts (like this one and predominantly for parts starting with LM) is that Phase starts from 0 degrees and goes negative. So in order to get Phase Margin, -180 has to be subtracted from the actual Phase at crossover.

In other parts (predominantly parts starting with TPS) you will see that phase starts from 180 degrees and goes towards 0 degrees. In this case, the phase at crossover is the phase margin, so it is easier to get phase margin directly.

Thanks,