VLSI implementation of implantable wireless power and data transmission micro-stimulator for neuromuscular stimulation

This paper presents the realization of the radio frequency (RF) power and data transmission for implantable microstimulators. This implantable device composes an internal RF front-end circuit, a control circuit, and a microstimulator. A 2 MHz AM-modulated signal including the power and data necessary for the implantable device is received, and a stable dc voltage and digital data will be extracted to further stimulate neuromuscular stimulation. In this implantable stimulator, the digital part is implemented by field programmable gate array (FPGA), and the analog part is implemented in a standard single-poly fifth-metal 0.25μm CMOS process. The latter occupies a silicon area smaller than 0.00638 mm² and produces an output current with 5-bit resolution for stimulations. The measuring stimulating current is 2.77 mA while the stimulation frequency is from 20 Hz to 2 kHz and the pulse width of stimulation current is from 100μs to 450μs. In addition, the simulation results of the RF front-end circuit and the verification of the control logic circuit are also presented in this paper.