Electric field rejection of a dual coil telemetry system

1 . A telemetry system for communicating with an implantable medical device, the telemetry system comprising:

telemetry circuitry configured to wirelessly communicate with the implantable medical device and being located on a circuit board;

a first bobbin, the first bobbin being located on a first side of the circuit board;

a first coil, the first coil being wound on the first bobbin in a first direction;

a second bobbin, the second bobbin being located on a second side of the circuit board; and

a second coil, the second coil being wound on the second bobbin in a second direction, the second direction being opposite to the first direction;

wherein an outer loop of the first coil and an outer loop of the second coil are electrically coupled together; and

a switch configured to be open when a telemetry system receiver is not in use and to be closed when the telemetry system receiver is in use, wherein a first portion of the switch is electrically coupled to the outer loop of the first coil and the outer loop of the second coil, and a second portion of the switch is electrically coupled to ground.

2 . The telemetry system of claim 1 , wherein the outer loop of the first coil and the outer loop of the second coil are electrically coupled together by being coupled to a same pin or by being coupled in the circuit board.

3 . The telemetry system of claim 1 , wherein the telemetry circuitry comprises a differential receiver, the differential receiver comprising a first receiver input and a second receiver input, an inner loop of the first coil being electrically coupled to the first receiver input and an inner loop of the second coil being electrically coupled to the second receiver input.

4 . The telemetry system of claim 1 , further comprising:

a first conductive spray coating located on a surface of the first bobbin; and

a second conductive spray coating located on a surface of the second bobbin,

wherein the first conductive spray coating and the second conductive spray coating are electrically coupled to the ground.

5 . The telemetry system of claim 1 , further comprising:

at least one shield cover, the at least one shield cover substantially surrounding the first bobbin and the second bobbin.

6 . The telemetry system of claim 1 , wherein the first bobbin comprises a first plastic structure and the second bobbin comprises a second plastic structure.

7 . The telemetry system of claim 1 , wherein the first bobbin and the second bobbin comprise a single plastic structure.

8 . The telemetry system of claim 1 , wherein a first device is the implantable medical device and wherein the telemetry circuitry is configured to receive data from the implantable medical device via the first coil and the second coil.

9 . The telemetry system of claim 8 , further comprising a computing device comprising processing circuitry, the processing circuitry being configured to process the received data.

10 . A method comprising:

placing telemetry circuitry on a circuit board, the telemetry circuitry being configured to wirelessly communicate with an implantable medical device;

winding a first coil on a first bobbin in a first direction;

winding a second coil on a second bobbin in a second direction, the second direction being opposite to the first direction;

placing the circuit board between the first bobbin and the second bobbin such that the first bobbin is located on a first side of the circuit board and the second bobbin is located on a second side of the circuit board; and

electrically coupling an outer loop of the first coil to an outer loop of the second coil; and

a switch configured to be open when a telemetry system receiver is not in use and to be closed when the telemetry system receiver is in use, wherein a first portion of the switch is electrically coupled to the outer loop of the first coil and the outer loop of the second coil, and a second portion of the switch is electrically coupled to ground.

11 . The method of claim 10 , wherein electrically coupling the outer loop of the first coil to the outer loop of the second coil comprises electrically coupling the outer loop of the first coil and the outer loop of the second coil to a same pin or in the circuit board.

12 . The method of claim 10 , wherein the telemetry circuitry comprises a differential receiver, the differential receiver comprising a first receiver input and a second receiver input, and wherein the method further comprises:

electrically coupling an inner loop of the first coil to the first receiver input; and

electrically coupling an inner loop of the second coil to the second receiver input.

13 . The method of claim 10 , further comprising:

electrically coupling first portion of the switch to the outer loop of the first coil and the outer loop of the second coil; and

electrically coupling a second portion of the switch to the ground,

wherein the switch is configured, during operation of a computing device, to be open when a telemetry system is not in use and to be closed when the telemetry system is in use.

14 . The method of claim 10 , further comprising:

depositing a first conductive spray coating on a surface of the first bobbin;

depositing a second conductive spray coating on a surface of the second bobbin; and

electrically coupling the first conductive spray coating and the second conductive spray coating to the ground.

15 . The method of claim 10 , further comprising:

placing at least one shield cover to substantially surrounding the first bobbin and the second bobbin.

16 . The method of claim 10 , wherein the first bobbin comprises a first plastic structure and the second bobbin comprises a second plastic structure.

17 . The method of claim 16 , wherein the first plastic structure and the second plastic structure comprise a single plastic structure.

18 . The method of claim 10 , wherein the telemetry circuitry is configured to, during operation, wirelessly receive data from the implantable medical device via the first coil and the second coil.

19 . A telemetry system for communicating with an implantable medical device, the telemetry system comprising:

telemetry circuitry configured to wirelessly communicate with a first the implantable medical device and being located on a circuit board;

at least one bobbin, the at least one bobbin being located on a first side of the circuit board;

a first coil, the first coil being wound on the at least one bobbin in a first direction;

a second coil, the second coil being wound on the at least one bobbin in a second direction, the second direction being opposite to the first direction, wherein an outer loop of the first coil and an outer loop of the second coil are electrically coupled together; and

a switch configured to be open when a telemetry system receiver is not in use and to be closed when the telemetry system receiver is in use, wherein a first portion of the switch is electrically coupled to the outer loop of the first coil and the outer loop of the second coil, and a second portion of the switch is electrically coupled to ground.