Event-driven sensor processor for accuracy-energy trade-off applications

Abstract

The latest sensor interface adopts the dedicated processor, which is integrated with the conventional sensor analog front-end, to identify the proper events from the change of the electrical signal such as touch, proximity, temperature, motion, and IR(infrared radio) indicative signal as an example of rare-event sensing applications. The operating lifetime of the sensor systems including the sensor analog-front-end and sensor processor is becoming major research topics by enhancing the circuit level improvement and architectural innovation. In this dissertation, a specially-designed, event-driven sensor processor architecture for the rare-event sensing applications is proposed by allowing the accuracy error, which is caused by the characteristics of the sensing applications. The conventional sensor processor performs the discrete-time based data sampling, data-quantization and utilizes the advanced time-quantization approach to reduce the energy consumption. Especially, for the rare-event applications, in which the event-to-event distance is very long, can be represented with the pre-defined event signal for a certain amount of signal range by the event type data of the signal shape and featured elapsed time range. The received analog signals for the specified time region are converted into the series of the atomic events by the signal-to-event converter (S2E) before the sensor data processing is performed. The signal-to-event conversion approach consumes additional power consumption, but the entire signal sampling rate can be reduced, which is more effective way to reduce the energy consumption. The event conversion concept allowing the accuracy error is proposed to utilize application-specific constraints to reduce the power consumption in the dedicated oscillator and timer, in which large amount of current is needed for the conventional time-quantization. The event-driven sensor data processing unit is also proposed to identify the final detected event usin...