Transcutaneous Power and Ultrasonic Blood-Flow Velocity Sensors,
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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The use of transcutaneous power to operate an implanted ultrasonic blood-flow sensor is analyzed. The purpose of such a study is the total elimination of batteries. The theory of transcutaneous power is developed from the basic equations of Maxwell and Stefan and a basic efficiency statement is derived. Design guidelines and graphs are generated from this statement and basic experiments are conducted to indicate the validity of the theory. The conclusion is that a properly designed and applied transcutaneous power-transfer circuit is capable of efficiencies as high as 90. A high-efficiency low-voltage regulator and a low-voltage reference are developed. This regulator and reference are compatibile with existing low-voltage implantable circuits intended initially to be battery powered. An extensive program is described involving the design, fabrication and employment of a discrete-component continuous-wave implanted ultrasonic doppler blood-flow velocity sensor. Transcutaneous power, low-voltage regulator design and the original ultrasonic blood-flow unit are combined in the first of its kind transcutaneously powered blood-flow velocity sensor. The details of this sensor are described in addition to the results of two implants with a prototype unit.
- Anatomy and Physiology