Title :
A Sub-nW Multi-stage Temperature Compensated Timer for Ultra-Low-Power Sensor Nodes
Author :
Yoonmyung Lee ; Giridhar, B. ; Zhiyoong Foo ; Sylvester, Dennis ; Blaauw, David B.
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Univ. of Michigan, Ann Arbor, MI, USA
Abstract :
Accurate measurement of synchronization cycle time is required for ultra-low power wireless sensor nodes with stringent power budgets. A multi-stage gate-leakage-based timer with boosted charging is proposed to address the high jitter of prior-art gate-leakage-based timers. The key approaches are faster load capacitor charging, wider voltage swing, and an improved gain sensing inverter. The proposed timer reduces RMS jitter by 8.1× and synchronization uncertainty by 4.1×, which allows hourly tracking with 200 ms uncertainty while consuming 660 pW. A novel closed-loop temperature compensation scheme with dynamic leakage adjustment is also proposed to achieve temperature sensitivity of 31 ppm/°C.
Keywords :
invertors; low-power electronics; wireless sensor networks; RMS jitter; boosted charging; closed-loop temperature compensation scheme; dynamic leakage adjustment; improved gain sensing inverter; load capacitor charging; multistage gate-leakage-based timer; power 660 pW; stringent power budgets; sub-nW multistage temperature compensated timer; synchronization cycle time; temperature sensitivity; time 200 ms; ultra-low power wireless sensor nodes; voltage swing; Jitter; Logic gates; Oscillators; Temperature dependence; Temperature measurement; Temperature sensors; Uncertainty; Timer; ultra-low power; wireless sensor node;
Journal_Title :
Solid-State Circuits, IEEE Journal of
DOI :
10.1109/JSSC.2013.2275660