A super-regenerative-oscillator wake-up receiver for underwater applications with improved PVT immunity

Abstract

A novel super-regenerative wake-up receiver for underwater communication systems is presented. Optimized wake-up receiver design for underwater communications plays an important role in increasing the deployment duration of sensor nodes through reduced power consumption. In this work, the super-regenerative oscillator (SRO) based receiver is designed to receive 20 kHz underwater acoustic signal. To enable high sensitivity without compromising the loop gain, a novel current-reuse SRO architecture is proposed using adaptive bulk biasing to increase negative transconductance $$ - G_{m} $$ under the same biasing current with improved sensitivity and start-up time. Differential input transistors with dynamic threshold control techniques are used to increase input transconductance and improve the gain without the need of a front-end low noise amplifier. A differential switch-controlled charge-pump is adopted to provide the quenching mechanism for the SRO. Furthermore, additional digital automatic gain control, frequency-lock loop, and common mode feedback are designed to improve the SRO immunity under process–voltage–temperature variations. The proposed super-regenerative receiver is implemented in TSMC 180 nm CMOS technology with center frequency of 20 kHz. It achieves sensitivity of − 83 dBm with data rate of 100 kbps and power consumption of 114 μW.