WEBENCH® Tools/LM5164: Measurement of switching pin and current through to the Inductor is completely different by the webench simulation

Jonathan Geronga

Part Number: LM5164

Tool/software: WEBENCH® Design Tools

Hi Team,

The customer used LM5164 for converting the DC-48V to 28.8V @ 420mA and use a TI webench for design the buck converter below:

They measure the switching pin and also measure the current through to the Inductor but saw the signal shape is completely different by the simulation:

Green signal is inductor current
The blue one is SW pin
Purple is FB pin

They use the 220uH inductor from Wurth (MPN is : 74404084221)
In output they don't have any resistor series with the capacitor, just have a 4.7uF

Please let me know your comment or any question to the customer to resolve the issue.

Thanks,

Jonathan

over 4 years ago

0 iAlejandro over 4 years ago

TI__Expert 8130 points

Hi Jonathan,

Can you please provide the waveforms generated by the simulation? What exactly is the difference?
I did notice a difference between WEBENCH and customer schematic. The resistor value for setting R_ON differ; R_ON sets the buck switch on-time.

Thanks,
Alejandro

0 Jonathan Geronga over 4 years ago in reply to iAlejandro

TI__Expert 7930 points

Hi Alejandro,

This thread can now be closed as the customer seems resolved this issue by themselves.

Thank you very much for your support.

Regards,

Jonathan

0 iAlejandro over 4 years ago in reply to Jonathan Geronga

TI__Expert 8130 points

Hi Jonathan,

Thanks for the update. Would you kindly share what the solution was? That way future viewers who have a similar problem might have the solution at hand.

Thanks!
Alejandro

Power management

Power management forum

WEBENCH® Tools/LM5164: Measurement of switching pin and current through to the Inductor is completely different by the webench simulation