Abstract: A method and apparatus related to detecting the presence of a power transfer coil implanted in a patient are disclosed. According to the aspect, an external device of a medical implant system is provided, the external device having an external coil and processing circuitry. The processing circuitry is configured to monitor a resonance frequency associated with the external coil. When the resonance frequency changes as a distance between the external coil and an expected location of an internal coil, then the processing circuitry is configured to conclude that the internal coil has been detected. When the resonance frequency ramps up to a steady state value at a rate that falls below a rate threshold, then the processing circuitry is configured to conclude that the internal coil is connected to an internal load.

Abstract: A device, such as an IMD, having a tissue conductance communication (TCC) transmitter controls a drive signal circuit and a polarity switching circuit by a controller of the TCC transmitter to generate an alternating current (AC) ramp on signal having a peak amplitude that is stepped up from a starting peak-to-peak amplitude to an ending peak-to-peak amplitude according to a step increment and step up interval. The TCC transmitter is further controlled to transmit the AC ramp on signal from the drive signal circuit and the polarity switching circuit via a coupling capacitor coupled to a transmitting electrode vector coupleable to the IMD. After the AC ramp on signal, the TCC transmitter transmits at least one TCC signal to a receiving device.

Abstract: An external power source, implantable medical device, and method for indicating an extent of power transfer between an external coil to an internal coil associated with the implantable medical device. According to one aspect, a method includes determining a parameter that depends on an extent to which the external coil is aligned with the internal coil, where the parameter includes at least one of an indication of an internal coil output power and power transfer efficiency and a resonant frequency of the external coil when inductively coupled to the internal coil. The method further includes indicating an extent to which the external coil is aligned with the internal coil based on the parameter.

Abstract: A device includes a tissue conduction communication (TCC) transmitter that generates a TCC signal including a carrier signal having a peak-to-peak amplitude and a carrier frequency cycle length including a first polarity pulse for a first half of the carrier frequency cycle length and a second polarity pulse opposite the first polarity pulse for a second half of the carrier frequency cycle length. Each of the first polarity pulse and the second polarity pulse inject a half cycle charge into a TCC pathway. The TCC transmitter starts transmitting the TCC signal with a starting pulse having a net charge that is half of the half cycle charge and transmits alternating polarity pulses of the carrier signal consecutively following the starting pulse.

Abstract: A device is configured to transmit tissue conductance communication (TCC) signals by generating multiple TCC signals by a TCC transmitter of the IMD. The generated TCC signals are coupled to a transmitting electrode vector via a coupling capacitor to transmit the plurality of TCC signals to a receiving medical device via a conductive tissue pathway. A voltage holding circuit holds the coupling capacitor at a DC voltage for a time interval between two consecutively transmitted TCC signals.

Abstract: A device, such as an IMD, having a tissue conductance communication (TCC) transmitter controls a drive signal circuit and a polarity switching circuit by a controller of the TCC transmitter to generate an alternating current (AC) ramp on signal having a peak amplitude that is stepped up from a starting peak-to-peak amplitude to an ending peak-to-peak amplitude according to a step increment and step up interval. The TCC transmitter is further controlled to transmit the AC ramp on signal from the drive signal circuit and the polarity switching circuit via a coupling capacitor coupled to a transmitting electrode vector coupleable to the IMD. After the AC ramp on signal, the TCC transmitter transmits at least one TCC signal to a receiving device.

Abstract: A system, such as an IMD system, includes a tissue conductance communication (TCC) transmitter configured to generate a beacon signal by generating a carrier signal and modulating a first property of the carrier signal according to a first type of modulation. The TCC transmitter is configured to generate a data signal subsequent to the beacon signal by generating the carrier signal and modulating a second property of the carrier signal different than the first property according to a second type of modulation different than the first type of modulation.

Abstract: A pressure sensing system provides signals representative of a magnitude of pressure at a selected site. A sensor module includes a first transducer producing a first signal having an associated first response to pressure and strain applied to the sensor module and a second transducer producing a second signal having an associated second response to pressure and strain applied to the sensor module. A calculated pressure, a bending pressure error and a bend-compensated pressure are computed in response to the first signal and the second signal.

Abstract: A medical device and associated method determine a signal amplitude of a sensor signal produced by a MEMS sensor, compare the signal amplitude to a stiction detection condition, detect stiction of the MEMS sensor in response to the signal amplitude meeting the stiction detection condition, and automatically provide a corrective action in response to detecting the stiction.

Abstract: A medical device and associated method determine a signal amplitude of a sensor signal produced by a MEMS sensor, compare the signal amplitude to a stiction detection condition, detect stiction of the MEMS sensor in response to the signal amplitude meeting the stiction detection condition, and automatically provide a corrective action in response to detecting the stiction.

Abstract: A medical device and associated method convert an analog signal using an adaptable bit number. The medical device includes an analog-to-digital (A/D) converter for receiving an analog signal. The A/D converter has a full scale range and a total number of bits spanning the full scale range. The A/D converter converts the analog signal to a digital signal over conversion cycles using an adaptable bit number so that on at least a portion of the conversion cycles an adapted number of bits spanning a portion of the full scale range less than the total number of bits is used by the A/D converter to convert the analog signal.

Abstract: Various techniques are described for periodically performing a calibration routine to calibrate a low-power system clock within an implantable medical device (IMD) based on a high accuracy reference clock also included in the IMD. The system clock is powered continuously, and the reference clock is only powered on during the calibration routine. The techniques include determining a clock error of the system clock based on a difference between frequencies of the system clock and the reference clock over a fixed number of clock cycles, and adjusting a trim value of the system clock to compensate for the clock error. Calibrating the system clock with a delta-sigma loop, for example, reduces the clock error over time. This allows accurate adjustment of the system clock to compensate for errors due to trim resolution, circuit noise and temperature.

Abstract: A medical device and associated method convert an analog signal using an adaptable bit number. The medical device includes an analog-to-digital (A/D) converter for receiving an analog signal. The A/D converter has a full scale range and a total number of bits spanning the full scale range. The A/D converter converts the analog signal to a digital signal over conversion cycles using an adaptable bit number so that on at least a portion of the conversion cycles an adapted number of bits spanning a portion of the full scale range less than the total number of bits is used by the A/D converter to convert the analog signal.

Abstract: A medical device and associated method convert an analog signal using an adaptable number of comparisons between the analog signal and a reference signal. The medical device includes an analog-to-digital (A/D) converter for receiving an analog signal. The A/D converter has a full scale range and a total number of bits spanning the full scale range. The A/D converter converts the analog signal to a digital signal over conversion cycles using an adaptable number of comparisons. For at least one of the conversion cycles, the adaptable number of comparisons is less than the total number of comparisons required to convert the analog signal over the full scale range of the A/D converter.

Abstract: Various techniques are described for periodically performing a calibration routine to calibrate a low-power system clock within an implantable medical device (IMD) based on a high accuracy reference clock also included in the IMD. The system clock is powered continuously, and the reference clock is only powered on during the calibration routine. The techniques include determining a clock error of the system clock based on a difference between frequencies of the system clock and the reference clock over a fixed number of clock cycles, and adjusting a trim value of the system clock to compensate for the clock error. Calibrating the system clock with a delta-sigma loop, for example, reduces the clock error over time. This allows accurate adjustment of the system clock to compensate for errors due to trim resolution, circuit noise and temperature.

Abstract: Various techniques are described for periodically performing a calibration routine to calibrate a low-power system clock within an implantable medical device (IMD) based on a high accuracy reference clock also included in the IMD. The system clock is powered continuously, and the reference clock is only powered on during the calibration routine. The techniques include determining a clock error of the system clock based on a difference between frequencies of the system clock and the reference clock over a fixed number of clock cycles, and adjusting a trim value of the system clock to compensate for the clock error. Calibrating the system clock with a delta-sigma loop, for example, reduces the clock error over time. This allows accurate adjustment of the system clock to compensate for errors due to trim resolution, circuit noise and temperature.

Abstract: An implantable medical sensor system provides signals representative of a magnitude of moment fraction applied to a sensor module at a selected site. A sensor module includes a first transducer producing a first signal having an associated first response to pressure and strain applied to the sensor module and a second transducer producing a second signal having an associated second response to pressure and strain applied to the sensor module. A moment fraction is computed in response to the first signal and the second signal. In various embodiments, the moment fraction is used to guide positioning of the sensor module, indicate a need for repositioning the sensor module, report loading of the sensor module during normal operation for use as sensor design information and in setting sensor calibration ranges.

Abstract: This disclosure is directed to an implantable medical device having a communication dipole configured in accordance with the techniques described herein. In one example, the disclosure is directed to an implantable medical device comprising a housing that encloses at least a communication module, a first electrode of a communication dipole electrically coupled to the communication module and an electrically conductive fixation mechanism that is electrically coupled to a portion of the housing and wherein a portion of the fixation mechanism is configured to function as at least part of a second electrode of the communication dipole. The electrically conductive fixation mechanism includes a dielectric material that covers at least part of a surface of the fixation mechanism. The communication module is configured to transmit or receive a modulated signal between the first electrode and second electrode of the communication dipole.

Abstract: This disclosure is directed to the synchronization of clocks of a secondary implantable medical device (IMD) to a clock of a primary IMD. The secondary IMD includes a communications clock. The communications clock may be synchronized based on at least one received communications pulse. The secondary IMD further includes a general purpose clock different than the communications clock. The general purpose clock may be synchronized based on at least one received power pulse. The communications clock may also be synchronized based on the at least one received power pulse.

Abstract: A reflectance-type optical sensor includes one or more photodiodes formed in a semiconductor substrate. A well having sidewalls and a bottom is formed in the top surface of the substrate, and a reflective layer is formed on the sidewalls and bottom. A light-emitting diode (LED) is mounted in the well, so that light emitted laterally and rearwardly from the LED strikes the sidewalls or bottom and is redirected in a direction generally perpendicular to the top surface of the substrate. The optical sensor can be fabricated using microelectromechanical systems (MEMS) fabrication techniques.