An Energy-Efficient Bridge-to-Digital Converter for Implantable Pressure Monitoring Systems.

Area of Science:

• Biomedical Engineering
• Integrated Circuits
• Sensor Technology

Background:

• Accurate pulmonary artery pressure monitoring is crucial for managing heart failure and pulmonary hypertension.
• Existing implantable sensors face challenges with power consumption and noise.

Purpose of the Study:

• To develop an energy-efficient, duty-cycled, spinning excitation bridge-to-digital converter (BDC) for implantable pressure sensing.
• To improve the monitoring of pulmonary artery pressure in patients.

Main Methods:

• Designed and fabricated a readout integrated circuit (IC) using a 180-nm CMOS process.
• Implemented a spinning excitation and simultaneous ADC input voltage strategy.
• Utilized duty cycling to minimize static power consumption and cancel noise.

Main Results:

• Achieved 8.4 effective number of bits (ENOB) at 1 kHz sampling rate with 0.53 μA current draw.
• Demonstrated 0.44 mmHg resolution over a 270 mmHg range with 1 ms conversion time.
• Reduced bridge sensor current consumption by 99.8% using duty cycling.

Conclusions:

• The proposed BDC offers state-of-the-art performance in energy efficiency and resolution for implantable pressure sensing.
• This technology has significant potential for improving patient care in cardiovascular diseases.
• The design effectively addresses power consumption and noise limitations in current systems.