The incorporation of artificial intelligence into the rapidly growing IoT devices demands a high level of built-in intelligence, e.g. machine learning capability at the device level. Affective computing offers a new degree of cognitive intelligence into edge processing IoT devices by inferring human emotion, stress levels for intelligent human assistance. This work explores the design space and runtime optimization opportunity for affective computing at the system-on-chip (SoC) level. A design optimization methodology for the neural network classifier and runtime power management schemes are proposed to achieve high energy efficiency on embedded low power devices. A test chip based on a 65nm CMOS process was used to demonstrate the proposed methodology on emotion and stress classification for affective computing. An average power saving of 45% is achieved with a peak power savings of 60% from the proposed emotion-driven adaptive power management scheme.

Modern biomedical devices use sensor fusion techniques to improve the classification accuracy of motion intent of users for rehabilitation application. The design of motion classifier observes significant challenges due to the large number of channels and stringent communication latency requirement. This paper proposes an edge-computing distributed neural processor to effectively reduce the data traffic and physical wiring congestion. A special local and global networking architecture is introduced to significantly reduce traffic among multi-chips in edge computing. To optimize the design space of the features selected, a systematic design methodology is proposed. A novel mixed-signal feature extraction approach with assistance of neural network distortion recovery is also provided to significantly reduce the silicon area. A 12-channel 55nm CMOS test chip was implemented to demonstrate the proposed systematic design methodology. The measurement shows the test chip consumes only 20uW power, more than 10,000X less power than the current clinically used microprocessor and can perform edge-computing networking operation within 5ms time.