A 695 pW standby power optical wake-up receiver for wireless sensor nodes

We propose an ultra-low power optical wake-up receiver with a novel front-end circuit and communication scheme suitable for miniature wireless sensor node applications. Named “FLOW” for Free-space Low-Power Optical Wake-up, the receiver consumes 695pW in standby mode, which is ~6,000× lower than previously reported RF and ultrasound wake-up radios. In active mode, it consumes 140pJ/bit at 91bps. A pulse width modulated communication encoding scheme is used, and chip-ID masking enables selective batch-programming and synchronization of multiple sensor nodes.