Wireless re-charge of an implantable medical device

A near-field energy transmitter for charging an implantable medical device (1 MB), the transmitter comprising:

• a transmit coil configured to transmit near-field energy to the IMD;
• an output driver for driving the transmit coil so that the transmit coil transmits the near-field energy at a transmit frequency and a transmit amplitude, wherein at least one of the transmit frequency and transmit amplitude is adjustable;
• a communication block for communicating with the IMD, wherein the communication block is configured to receive one or more messages from the IMD regarding the transmit power that is received by the IMD;
• and
• a controller operatively coupled to the output driver and the communication block, the controller configured to adjust one or more of the transmit frequency and transmit amplitude of the near-field energy so that the transmit power that is received by the IMD meets a predetermined criteria.

A near-field energy transmitter for charging an implantable medical device (IMD), the transmitter comprising:

• a transmit coil configured to transmit near-field energy to the IMD;
• an output driver for driving the transmit coil so that the transmit coil transmits the near-field energy at a transmit frequency, wherein the transmit frequency is adjustable;
• a monitor operatively coupled to the output driver for detecting a transmit power of the transmitted near-field energy;
• a controller operatively coupled to the output driver and the monitor, the controller configured to:
• cause the output driver to adjust the transmit frequency of the near-field energy across two or more transmit frequencies;
• identify the transmit power of the near-field energy at each of the two or more transmit frequencies using the monitor;
• select the transmit frequency of the two or more transmit frequencies that results in a transmit power that has a predetermined characteristic;
• and
• set the transmit frequency of the output driver to the selected transmit frequency;
• wherein the controller is configured to detect a decrease in the transmit power at the selected transmit frequency, and in response:
• cause the output driver to adjust the transmit frequency of the near-field energy across two or more transmit frequencies;
• identify the transmit power of the near-field energy at each of the two or more transmit frequencies;
• select the transmit frequency of the two or more transmit frequencies that results in a transmit power that has a predetermined characteristic;
• and
• set the transmit frequency of the output driver to the selected transmit frequency.