34.6 EEG Dust: A BCC-Based Wireless Concurrent Recording/Transmitting Concentric Electrode
Tao Tang, Long Yan, Jeong Hoan Park, Han Wu, Lian Zhang, Benjamin Ho Yin Lee, Jerald Yoo
Abstract
EEG recording technology creates the opportunity to sense and discover potential fluctuation in the human brain [1]. Quantitative analysis based on various EEG sensor nodes provide vital information on the patient's mental and physiological status. However, conventional multi-channel work requires wire connections and thus suffers from huge environmental interference, which makes it difficult to be wearable and durable for daily EEG monitoring. Some work [2] tried to solve the problem of common mode interference from power line coupling by using a common mode charging pump (CMCP) technique, which cancels out a certain amount of common mode voltage. However, the charging speed of the capacitor makes it unsuitable when coupled common mode potential changes over time and environment. Some work [3] proposed a floating power system with an on-chip frequency-controlled LDO, while it requires all channels tied together to average out the common mode potential and forced a power plane to be shared by all of them, which works for implantable neural recording system instead of a widespread distributed EEG recording system. Moreover, a conventional EEG recording system requires a separate reference electrode, which introduces more connection wires and extra interferences. For the active electrode [4], which removes the input connection wires to reduce common mode interference, the potential difference between circuit ground and human body is another essential issue, a driven-right leg circuit is used in [4] leads to extra wire/interference and stability issue. Work in [5] proposed in-ear EEG AFE with BCC transmission, however, concurrent signal recording/BCC transmission is not reported.