Pressure telemetry implant

摘要

An implantable intracranial pressure (ICP) telemetry transmitter. Data transmission is accomplished by means of a radio frequency (RF) link coupled to a silicon piezoresistive pressure transducer. Electrostatic bonding of this transducer onto a tubular glass support provides long-term stability, stress isolation and a hermetic package. Because of the large temperature coefficient of the electrostatically bonded pressure transducer (-6 to -9 mm Hg/ DEG C.), a temperature sensor is added to allow temperature compensation to be carried out. Pulse code modulation is employed to assure accurate data transmission. Use of low duty cycle pulse powering techniques lowers the power consumption of the telemeter. The complexity of the electronics is reduced by the use of a custom integrated circuit. Two lithium batteries can provide more than one month of continuous operation and an RF command receiver provides ON/Off control of the telemeter to extend the lifetime of the telemeter.