Method and Apparatus for Guiding an External Needle to an Implantable Device

A method of operating a localizer associated with an implanted medical device having a single power source to generate a navigation field and transmit telemetry from the implanted medical device, the method comprising:

• operating the implanted medical device to deliver a therapy to a patient including drawing a current from the single power source;
• sending a stop signal to a receiver in the implanted medical device to stop the operation of the implanted medical device from delivering the therapy;
• in response to the stop signal, stopping the operation of the implanted medical device from delivering the therapy;
• after stopping operation of the implanted medical device from delivering the therapy, starting a port finder routine having sub-routines including starting a port finder timer to time the operation of the port finder routine;
• powering a coil to emit a field;
• determining whether the port finder timer has expired;
• when it is determined that the port finder timer has expired, restarting the operation of the implanted medical device to deliver the therapy.

A system to provide a constant amplitude alternating current and/or voltage to a localizer in an implanted medical device, comprising:

• an operational amplifier operable to receive an input voltage and output a reference voltage to a precision resistor and a first PMOS current mirror cascode;
• a NMOS current mirror operable to receive an output voltage from the precision resistor;
• a second PMOS current mirror cascode operable to receive an output voltage from the NMOS current mirror and the first PMOS current mirror cascode to output a substantially constant amplitude alternating current and/or voltage based on the output reference voltage;
• a first coil;
• a first capacitor;
• and
• a first switch to form a connection between the second PMOS current mirror cascode and the first coil and the first capacitor;
• wherein the first capacitor is operable to tune the frequency of the output from the first coil to a selected frequency.

A system for generating a field relative to an implanted medical device, comprising:

• a coil array positioned in the implanted medical device including a single coil or a plurality of coils each having a winding group formed on a circuit;
• a power source in the implanted medical device to power all components of the implanted medical device including the coil array;
• and
• a processor operable to energize the coil array according to selected instructions to assist in providing a current to the coil array;
• wherein each of the plurality of coils in the coil array is formed substantially thin in the flexible circuit to provide a substantially thin profile of the flexible circuit.

A system for receiving a field within an implanted medical device, comprising:

• a coil array positioned in the implanted medical device including a single coil or plurality of coils each having a winding group formed on a circuit;
• a power source in the implanted medical device to power all components of the implanted medical device;
• a processor operable to measure the signals from a received field according to selected instructions and generate data regarding the measured signals;
• and
• a telemetry processing system operable to receive the generated data regarding the measured signals to an external processor system;
• wherein the external processor system is operable to determine a location of an emitting system that is emitting the received field.

A method of operating a localizer associated with an implanted medical device having a power source to generate a navigation field and transmit telemetry from the implanted medical device, the method comprising:

• operating the implanted medical device to deliver a therapy to a patient including drawing a current from the single power source;
• sending a stop signal to a receiver in the implanted medical device to stop the operation of the implanted medical device from delivering the therapy;
• in response to the stop signal, stopping the operation of the implanted medical device from delivering the therapy;
• after stopping operation of the implanted medical device from delivering the therapy, starting a port finder routine having sub-routines including starting a port finder timer to time the operation of the port finder routine;
• powering a coil to emit a field;
• determining whether the port finder timer has expired;
• when it is determined that the port finder timer has expired, restarting the operation of the implanted medical device to deliver the therapy.