Ultrasound powered pulse delivery device

An implantable medical device system for delivering electrical stimulation pulses to a patient's body, comprising:

• an implantable pulse delivery device;
• and
• a second implantable device comprising an array of ultrasound transducers, a control circuit, and a first housing enclosing the array of ultrasound transducers and the control circuit, the control circuit configured to control the array to transmit ultrasound signals at a pulse delivery rate to the implantable pulse delivery device;
• the implantable pulse delivery device comprising:
• a second housing;
• a pair of electrodes carried by the second housing;
• a piezoelectric element that is enclosed by the housing and produces voltage signals in response to receiving ultrasound energy transmitted through the patient's body;
• and
• a circuit coupled to the piezoelectric element and configured to pass at least a portion of the voltage signals produced by the piezoelectric element to the pair of electrodes for delivering an electrical stimulation pulse to the patient's body, the circuit comprising a rate limiter configured to filter a voltage signal produced by the piezoelectric element that occurs at an interval less than a maximum pulse rate interval after a preceding voltage signal has been passed to the pair of electrodes.

An implantable medical device system for delivering electrical stimulation pulses to a patient's body, comprising:

• a first implantable device;
• and
• a second implantable device comprising an array of ultrasound transducers, a control circuit, and a first housing enclosing the array of ultrasound transducers and the control circuit, the control circuit configured to control the array to transmit ultrasound signals at an electrical stimulation pulse delivery rate to the first device;
• the first implantable device comprising:
• a second housing;
• a pair of electrodes carried by the second housing;
• a piezoelectric element enclosed by the housing and configured to produce a voltage signal in response to receiving ultrasound energy transmitted through a patient's body, the piezoelectric element, wherein the ultrasound energy comprises first ultrasound signals transmitted by the second implantable device and second, diagnostic ultrasound signals transmitted through the patient's body;
• and
• a circuit coupled to the piezoelectric element and configured to:
• deliver electrical stimulation pulses to the patient's body by passing a first portion of the voltage signals produced by the piezoelectric element in response to the first ultrasound signals transmitted by the second implantable device to the pair of electrodes, and
• filter a second portion of the voltage signals from being passed to the pair of electrodes, the second portion of the voltage signals produced by the piezoelectric element in response to the second, diagnostic ultrasound signals.