Addressable Microstimulator Circuit for Neural Prosthesis

Current state-of-the-art Brain-Machine Interfaces (BMIs) with multi-channel neural interfacing microsystem has been developed as the scale of CMOS process continuously miniatured. Further performance enhancement in BMIs relies on the ability to develop implantable integrated circuit system that would reduce the noise level and the power consumption to operate scalable thousands of channels. In this work, we describe a prototype of distributed wireless microimplants, which provide a high-density network of addressable neural stimulator system with an optical powering method. The proposed circuit built in a standard 0.18μm CMOS process, which include the rectifier, the binary phase-shift keying (BPSK) demodulator, the clock recovery, 9-bits metal fuses and the digital block to discriminate address for each chip. The circuit occupies 211×204 μm2 of silicon area totally, which would be a reasonable size for micro implant. A photovoltaic cell is used to provide efficient power as BPSK modulated signal with the supply voltage 3 V. The designed circuit consumes ~77μW at a data rate of 20 Mbps at 20 MHz carrier frequency. Keywords—Brain-machine interface, implantable sensor, wireless microstimulator