A novel envelope edge detector for ultra-low power sensor wake-up circuit

Voltage comparators have been widely used in low-power sensor wake-up circuits for extracting digital bits from the envelope of received RF signals. This paper presents an alternative circuit to such comparators. The proposed circuit extracts digital bits by detecting the falling edge of the envelope signal. Since it essentially compares the values of the same signal at different times, it is potentially more robust than the comparator based approach, which compares the peak voltage of the envelope signal with another reference voltage. The design issues for using the proposed edge detection circuit into different wake-up receiver architectures are discussed and simulation results are also presented to demonstrate the performance of the proposed circuit.