A Neural Recording Front End for Multi-channel Wireless Implantable Applications

A NEURAL RECORDING FRONT END FOR MULTI-CHANNEL WIRELESS IMPLANTABLE APPLICATIONS By Haitao Li By recording neurons’ activities simultaneously, awake animal behaviors can be predicted in real time, brain–machine interfaces controlling the machine by thought can be set up, and treatments for neurological disorders can be explored. Existing commercial neural recording equipment are bench-top systems that are bulky, high cost, consume high power, and require wire bundles tethering the neural recording probes to skull-mounted connector. To overcome these disadvantages, a miniature wireless implanted multi-channel integrated neural recording micro-system with low power and low noise is needed. This thesis work addresses the challenges to developing an analog front end for wireless implanted multi-channel neural recording systems, which include ultra low noise, extremely low power, high power supply rejection radio, low area occupation, sufficient data conversion speed and optimizing design tradeoff between all these requirements. Two versions of a neural amplifier were built. Following optimization guidelines in this thesis, noise efficiency and a new figure of merit for neural amplifiers were effectively improved. A successive approximation (SAR) ADC tailored to wireless implantable neural recording systems was also designed. The new SARADC is able to process 32 neural spikes recording channels in a multiplexing manner with low power consumption and low area occupation. The results of this research lay a solid foundation for future realization of high sensitivity wireless implantable neural recording system