WEBENCH® Tools: Coil Designer

Tarek Mostafa

Prodigy 60 points

Tool/software: WEBENCH® Design Tools

Hi everyone,

I designed the following coil with the help of Coil Designer TI WEBENCH

Outer Diameter (Dout): 40 mm
Number of Layers: 2
Turns per layer: 35
Trace width (W): 0.2 mm
Spacing between Traces (S): 0.2 mm
Inner Diameter (Din): 12 mm
Space between 1st layer and 2ndlayer(x12) = 1.5 mm

This gave me L=94.8 uH, but after fabrication and measurements, it always gives me 4 uH.

Any help?

I have pictures for the coil and the measurements if needed.

over 7 years ago

0 Amod Vaze over 7 years ago

TI__Mastermind 28610 points

Hi Tarek,

Thank you for your question. I am trying to find the right contact who can help with this question. I will get back on this soon.

Regards,

Amod

0 Tarek Mostafa over 7 years ago in reply to Amod Vaze

Prodigy 60 points

Hi Amod,

Thank you so much for your very kind support, looking forward to your feedback.

Best Regards,

Tarek

0 Clancy Soehren over 7 years ago in reply to Tarek Mostafa

TI__Mastermind 23810 points

Tarek,

Please send us pictures. It shouldn't be so far off of the webench estimate. Perhaps one of the coils is partially shorted? Or maybe there is a problem with how you are measuring the coils?

0 Tarek Mostafa over 7 years ago in reply to Clancy Soehren

Prodigy 60 points

Dear Clancy,

Thank you so much for your kind reply.

Please find the photos in this link

I used the Keysight impedance analyzer for measurements and it's not the first time to measure a coil

0 Clancy Soehren over 7 years ago in reply to Tarek Mostafa

TI__Mastermind 23810 points

Tarek,

Everything looks OK, but I can't tell anything from the picture of the coil (too low resolution). My suspicion is that there was a problem with the PCB manufacturing. You might be able to tell with a visual inspection.

To double check that the impedance analyzer measurement is correct, you could try adding the parallel capacitor and connecting it to one of the LDC devices. From that, you can check the inductance by measuring the frequency of oscillation (which you can measure on the oscilloscope or with the output of the LDC device).

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WEBENCH® Tools: Coil Designer