LM61440: Simulation error - "There are no waveforms for this simulation."

Nelson Cavaco

Part Number: LM61440

Tool/software:

Hey everyone,

So I got to try this simulation tool WeBench Power Designer for a DCDC buck converter.

My requirements are quite on the edge:

Vin: 5V to 35V
Iout: 4A max
Vout: 4.4V

The thing is that with these parameters I am reaching max duty cycle apparently. So I modified the parameters for the simulation to work:

With this I can get all the simulations to run but not the "Input Transient" one.

whats happening?
If someone could help me or facilitate me an IC for those requirements would be great thanks :)

8 months ago

0 Joshua Austria 8 months ago

TI__Mastermind 24135 points

Hi,

Thank you for sending this information over. Could you also please send over the webench design that you are using so I can help you debug this?

Thank you,

Joshua Austria

0 Nelson Cavaco 8 months ago in reply to Joshua Austria

Prodigy 40 points

What do you mean?

The system doesnt allow me to export the design.

Just type LM61440AANRJRR in the part number search bar, modify the parameter for the ones above and you can easily replicate this behavior.

0 Joshua Austria 8 months ago in reply to Nelson Cavaco

TI__Mastermind 24135 points

Hi Nelson,

If you click the three dots in the upper right hand corner you can create a link to share. I believe this method would be the easiest to ensure that we have the starting point to accurately debug this.

Thank you,

Joshua Austria

0 Nelson Cavaco 8 months ago in reply to Joshua Austria

Prodigy 40 points

Hey Joshua,

Please see the link below:

https://webench.ti.com/appinfo/webench/scripts/SDP.cgi?ID=EA75A655C0B5C2CD

Thank you for your help,

Nelson

+1 Joshua Austria 8 months ago in reply to Nelson Cavaco

TI__Mastermind 24135 points

Hi Nelson,

The problem seems to be with the input voltage parameters. Changing the parameters from 5-35 V to 12-36 V resolves the issue and a waveform is achievable:

I believe the device may not be able to handle such a dramatic swing in input voltage during the stated load and temperature parameters.

Are you expecting a 5-35 V swing on input on the order of 10s of usec? If not, I would recommend testing this on the bench with the EVM modified to your parameters to get a better understanding of the true input voltage transient that is suspected for this application.

Thank you,

Joshua Austria

0 Nelson Cavaco 8 months ago in reply to Joshua Austria

Prodigy 40 points

Hey Joshua,

ok. Fair enough. Thank you so much for your helping on this matter.

Thank you,

Nelson

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LM61440: Simulation error - "There are no waveforms for this simulation."