An implantable wireless bidirectional communication microstimulator for neuromuscular stimulation

TLDR

The study presents an integrated circuit design for a wireless bidirectional microstimulator enabling neuromuscular stimulation. The device integrates an RF front‑end, control, stimulator, and on‑chip transmitter in a single TSMC 0.35‑µm CMOS chip, using 2‑MHz ASK to deliver 3‑V DC and digital data, providing 8‑bit resolution stimulation currents up to 1 mA at 20 Hz–2 kHz with 150–500 µs pulse widths while also acquiring biological signals with low‑power processing.

Abstract

This paper presents the integrated circuit design for a wireless bidirectional transmission microstimulator. This implantable device is composed of an internal radio-frequency (RF) front-end circuit, a control circuit, a stimulator, and an on-chip transmitter. A 2-MHz amplitude-shift keying modulated signal, including the power and data necessary for the implantable device, is received, and a stable 3-V dc voltage and digital data will be extracted to further execute neuromuscular stimulation. The current-mode microstimulator can produce a bidirectional output current with 8-bit resolution for stimulation. The maximum stimulation current is 1 mA while the stimulation frequency is from 20 Hz to 2 kHz and the pulsewidth of stimulation current is from 150 to 500 /spl mu/s. Furthermore, the system can acquire the biological sensing signal by means of an on-chip transmitter. Most of the signal processing circuits have been designed with low-power schemes to reduce the power consumption, and the performance is also conformed to the requirements of the microstimulator. All of the circuits except for the RF link are combined in a single chip and implemented in TSMC 0.35-/spl mu/m 2P4M standard CMOS process.