Design Of A Temperature-Robust Ultra-Low Power Wake-Up Receiver With High Sensitivity

With the continuous advancement of technology in integrated circuits and wireless communication,the vision of the Internet of Everything has changed from science fiction to reality.Wireless sensor networks（WSNs）is the cornerstone technology of the Internet of Things.With the gradual popularization of Internet of things applications,the chips used for WSNs have attracted more and more attention.The development of WSNs technology puts forward the requirements of miniaturization and long battery life for node devices.However,the increase in wireless communication distance greatly increases the power consumption of the main radios.Therefore,in energy-limited WSNs node applications,the main radios for communication must operate in a deep-sleep mode in an inactive state to reduce power consumption to prolong node battery life.The Wake-Up working mode is one of the most effective low-power schemes for WSNs nodes,using the wake-up receiver to wake up the main radios only when data communication is required.For the low average throughput WSNs applications,this thesis discussed the design of the ultra-low power wake-up receivers.In this article,the OOK modulation method is selected,and the direct RF signal detection wake-up receiver architecture with the direct envelope detector is adopted.Through the detailed analysis and modeling of the system noise,a temperature-robust,high sensitivity,and ultra-low power wake-up receiver is proposed.The main work of this thesis is as follows:（1）A bulk-tuned differential passive envelope detector with common-mode bias is proposed,solving the problem of floating DC-coupled bias.Moreover,its conversion gainis twice that of the single-ended output envelope detector and the sensitivity of the receiver is improved by 1.5d B.（2）An optimal design method based on boundary impedance conditions is proposed in the RF front-end and baseband circuit interface design to obtain the best sensitivity and the lowest power consumption.（3）A low-voltage and low power fully differential baseband amplifier with current-reusing based on inverter is proposed to reduce power consumption and improve robustness.（4）An offset calibration loop based on a dual-path envelope detector and a delay-locked loop is proposed,which eliminates the DC offset and low-frequency flicker noise of the two differential paths,optimizing the input signal-to-noise ratio before signal demodulation and improve the Anti-interference ability.（5）An ultra-low power area saving temperature compensated timer based on gate leakage is proposed to provide the system clock required to wake up the receiver,which improves the robustness of the ultra-low power wake-up receiver in the temperature range of 0～70°C.Based on TSMC 65nm LP CMOS process,this thesis completed the circuit design and physical layout implementation of the proposed temperature-robust,high-sensitivity,and ultra-low-power wake-up receiver.The realized wake-up receiver is compatible with the ISM frequency band,using a carrier frequency of 915 MHz and a data transmission rate of100 bps.The post-simulation results show that,the proposed temperature compensated timer realizes a 1.6k Hz system clock with a frequency temperature drift coefficient of 98ppm/℃from 0 to 70℃,thus the proposed wake-up receiver can normally realize the wake-up function.Under the level of false alarm rate less than 1/h and missed detection rate less than10^-3,the proposed wake-up receiver achieves the sensitivity of-77.2d Bm.Under the supply voltage of 0.4V,the wake-up receiver consumes only 7.4n W,of which the temperature compensated timer consumes 3.76n W.The layout implementation results show that the area of the entire wake-up receiver chip is 1.39mm*0.79mm,of which the core circuit occupies an area of 0.72mm*0.36mm.