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Nath

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Magnetic field in the center of an on-chip transformer
Sep 16^th, 2014, 6:53pm

Hi,
I have a �fundamental question about the magnetic field in the center of an inter-wound symmetric monolithic transformer. As I understand it, the built in phase inversion from the primary to secondary of an inter-wound (lateral) transformer results in ZERO magnetic field at the center.
This is quite contrary to a spiral inductor whose field is strongest in the center. Does this make sense or am I not looking at this correctly? �

Regards,
Nath �

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loose-electron Senior Fellow Offline Best Design Tool = Capable Designers Posts: 1638 San Diego California	Re: Magnetic field in the center of an on-chip transformer Reply #1 - Sep 17^th, 2014, 8:09am care to provide a picture of what you are talking about?
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aaron_do Senior Fellow Offline Posts: 1398	Re: Magnetic field in the center of an on-chip transformer Reply #2 - Sep 18^th, 2014, 4:28am Hi Nath, I believe your reasoning is correct. The currents in the primary and secondary will be going in the opposite direction and the magnetic fields which they produce will cancel at the center of the transformer. Aaron
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totowo

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SH, PRC

Re: Magnetic field in the center of an on-chip transformer
Reply #3 - Nov 13^th, 2014, 11:25pm

According to Lenz's law, the secondary current is really trying to cancel the magnetic flux, but it is always more 'weak' to cancel all.

Nath wrote on Sep 16^th, 2014, 6:53pm:

Hi,
I have a �fundamental question about the magnetic field in the center of an inter-wound symmetric monolithic transformer. As I understand it, the built in phase inversion from the primary to secondary of an inter-wound (lateral) transformer results in ZERO magnetic field at the center.
This is quite contrary to a spiral inductor whose field is strongest in the center. Does this make sense or am I not looking at this correctly? �

Regards,
Nath �

Back to top

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