An Energy-Efficient ASK Demodulator Robust to Power-Carrier-Interference for Inductive Power and Data Telemetry

Area of Science:

• Biomedical Engineering
• Electrical Engineering
• Implantable Devices

Background:

• Amplitude-shift keying (ASK) modulation is common in wireless power and data telemetry for biomedical implants.
• Mutual inductance between power and data links causes power-carrier-interference (PCI), degrading signal-to-interference ratio (SIR) and increasing bit-error-rate (BER).

Purpose of the Study:

• To propose an innovative, high energy-efficient ASK demodulator robust to PCI.
• To enable reliable data demodulation in the presence of strong interference for implantable devices.

Main Methods:

• Development of a novel sampling-and-subtraction (SAS) architecture for the ASK demodulator.
• Implementation of a prototype using a 180 nm standard CMOS process, occupying a core area of 0.51 mm².

Main Results:

• The SAS demodulator effectively withstands PCI up to 2.5 times the data carrier amplitude without high-order filters.
• Achieved a typical bit-error-rate (BER) below 1.3×10⁻³ at 1 Mbps data rate and 13.56 MHz carrier frequency.
• Demonstrated exceptional energy efficiency of 280 pJ/bit, a 7.5× improvement over prior work.

Conclusions:

• The proposed ASK demodulator offers significant energy efficiency and robustness against PCI.
• This technology holds great potential for applications like retina prostheses and other ultra-low-power implantable biomedical devices.