Ultra-low power wake-up circuit for short-range wireless communication

A wake-up circuit sensitive to infrared signals is presented. The device is constantly active and waiting for a signal while consuming only four microamperes of current from a coin cell battery. The device also contains a transmission part for short reply messages using infrared signals. The piece of hardware could be used on its own for indoor positioning and various identification purposes as well as for waking up external hardware, e.g. sensor nodes or other battery powered objects in intelligent environments. Operating range for a wake-up signal is typically up to 30 metres depending on transmitter signal intensity.