  This article presents a hardware platform including stimulating implants
wirelessly powered and controlled by a shared transmitter (TX) for coordinated
leadless multisite stimulation. The adopted novel single-TX, multiple-implant
structure can flexibly deploy stimuli, improve system efficiency, easily scale
stimulating channel quantity, and relieve efforts in device synchronization. In
the proposed system, a wireless link leveraging magnetoelectric (ME) effect is
co-designed with a robust and efficient system-on-chip (SoC) to enable reliable
operation and individual programming of every implant. Each implant integrates
a 0.8-mm2 chip, a 6-mm2 ME film, and an energy storage capacitor within a
6.2-mm3 size. ME power transfer is capable of safely transmitting milliwatt
power to devices placed several centimeters away from the TX coil, maintaining
good efficiency with size constraints, and tolerating 60 degree, 1.5-cm
misalignment in angular and lateral movement. The SoC robustly operates with
2-V source amplitude variations that spans a 40-mm TX-implant distance change,
realizes individual addressability through physical unclonable function (PUF)
IDs, and achieves 90% efficiency for 1.5-3.5-V stimulation with fully
programmable stimulation parameters.
