Inductive structures with improved common mode transient immunity

Patent metadata

Field	Value
Publication number	US-9450651-B2
Application number	US-201414311354-A
Country	US
Kind code	B2
Filing date	Jun 23, 2014
Priority date	Jul 1, 2013
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

In a first inductive structure, a first data coil includes: a first portion for conducting a first common mode current in a first direction; and a second portion for conducting a second common mode current in a second direction opposite the first direction. The first and second portions of the first data coil are connected at a first node. In a second inductive structure, a second data coil includes: a first portion for conducting a third common mode current in the first direction; and a second portion for conducting a fourth common mode current in the second direction. The first and second portions of the second data coil are connected at a second node galvanically isolated from the first node. The first, second, third and fourth common mode currents are induced by a common mode transient.

First claim

What is claimed is:

1. A device, comprising:
a first inductive structure including a first data coil, wherein: a first portion of the first data coil is for conducting a first common mode current in a first direction; a second portion of the first data coil is for conducting a second common mode current in a second direction opposite the first direction; the first portion of the first data coil is connected at a first node to the second portion of the first data coil; and the first node is coupled to a first ground; and
a second inductive structure including a second data coil, wherein: a first portion of the second data coil is aligned with the first portion of the first data coil for conducting a third common mode current in the first direction; a second portion of the second data coil is aligned with the second portion of the first data coil for conducting a fourth common mode current in the second direction; the first portion of the second data coil is connected at a second node to the second portion of the second data coil; the second node is coupled to a second ground galvanically isolated from the first ground; and the first, second, third and fourth common mode currents are induced by a common mode transient that occurs with respect to the first and second grounds;
wherein the first and second portions of the first data coil are coupled to: receive data from a transmitter; and output the data by inductive coupling to the second data coil; and
wherein the first and second portions of the second data coil are coupled to: receive data by inductive coupling from the first data coil; and output the data to a receiver.

2. The device of claim 1 , and comprising:
an isolation barrier between the first and second inductive structures, wherein: the common mode current conducted in the first direction in the second data coil is capacitively induced across the isolation barrier by the common mode current conducted in the first direction in the first data coil; and the common mode current conducted in the second direction in the second data coil is capacitively induced across the isolation barrier by the common mode current conducted in the second direction in the first data coil.

3. The device of claim 1 , wherein the first inductive structure includes a first power coil, the first data coil is substantially centered within the first power coil, and the first power coil is for: receiving power from a transmitter; and outputting the power by inductive coupling to the second power coil.

4. The device of claim 3 , wherein the second inductive structure includes a second power coil, the second data coil is substantially centered within the second power coil, and the second power coil is for: receiving power by inductive coupling from the first power coil; and outputting the power to a receiver.

5. The device of claim 4 , wherein the first and second inductive structures are substantially identical to one another.

6. The device of claim 5 , wherein the first data coil is substantially centered within the first power coil.

7. The device of claim 6 , wherein the first and second portions of the first data coil are substantially identical to one another, yet reversed from one another.

8. A method, comprising:
conducting a first common mode current in a first direction through a first portion of a first data coil of a first inductive structure;
conducting a second common mode current in a second direction through a second portion of the first data coil, wherein: the second direction is opposite the first direction; the first portion of the first data coil is connected at a first node to the second portion of the first data coil; and the first node is coupled to a first ground;
conducting a third common mode current in the first direction through a first portion of a second data coil of a second inductive structure, wherein: the third common mode current is capacitively induced in response to the first current; and the first portion of the second data coil is aligned with the first portion of the first data coil;
conducting a fourth common mode current in the second direction through a second portion of the second data coil, wherein: the fourth common mode current is capacitively induced in response to the second current; the second portion of the second data coil is aligned with the second portion of the first data coil; the first portion of the second data coil is connected at a second node to the second portion of the second data coil; and the second node is coupled to a second ground isolated from the first ground;
with the first and second portions of the first data coil, receiving data from a transmitter, and outputting the data by inductive coupling to the second data coil; and
with the first and second portions of the second data coil, receiving data by inductive coupling from the first data coil, and outputting the data to a receiver.

9. The method of claim 8 , and comprising:
applying a common mode transient to the first inductive structure and capacitively coupling the common mode transient to the second inductive structure across an isolation barrier between the first and second inductive structure, wherein the third common mode current is substantially equal in magnitude to and opposite in polarity from the fourth common mode current.

10. The method of claim 8 , and comprising:
inducing a fifth common mode current in the first direction through the first portion of a second data coil; and
inducing a sixth common mode current in the second direction through the second portion of the second data coil; wherein: the fifth and sixth common mode currents are induced by capacitively coupling a first power coil to the data coil of the second inductive structure; and the first inductive structure includes the first power coil within which the first data coil is substantially centered.

11. The method of claim 8 , and comprising:
inducing a seventh common mode current in the first direction through the first portion of a second data coil; and
inducing an eighth common mode current in the second direction through the second portion of the second data coil; wherein: the seventh and eighth common mode currents are induced by capacitively coupling a second power coil to the data coil of the second inductive structure; and the second inductive structure includes the second power coil within which the second data coil is substantially centered.

12. The method of claim 8 , wherein the third and fourth common mode currents are substantially the same magnitude and are opposite in polarity to one another.

13. The method of claim 12 , and comprising:
high-pass filtering a signal that includes the data received by the second data coil.

14. A device, comprising:
a first inductive structure including a first data coil;
a second inductive structure including a second data coil, wherein the second data coil has a shape that is symmetric with respect to a shape of the first data coil, and wherein the first and second data coils are aligned with each other;
an isolation barrier between the first and second inductive structures, wherein the first data coil is for: receiving data from a transmitter; and outputting the data by inductive coupling across the isolation barrier to the second data coil; and
wherein the second data coil is for: receiving the data by inductive coupling across the isolation barrier from the first data coil; outputting the data to a receiver; receiving a capacitively coupled transient from the first inductive structure; generating a current of a first polarity in response to the capacitively coupled transient; and generating a cu

Assignees

• Texas Instruments Inc

Inventors

• Subramoniam Rajaram
• Lisi Gianpaolo
• Sankaran Swaminathan
• Kramer Bradley Allen
• Socci Gerard

Classifications

• H04B5/79 Primary

  for data transfer in combination with power transfer · CPC title

• H04B5/263 Primary

  Multiple coils at either side · CPC title

• H04B5/0037

  Electricity · mapped topic

• H04B5/0087 Primary

  Electricity · mapped topic

• H04B5/0031

  Electricity · mapped topic