Intermittent Excitation of High-Q Resonators for Low-Power High-Speed Clock Generation

There is growing demand for circuits that can provide ever greater performance from a minimal power budget. Example applications include wireless sensor nodes, mobile devices, and biomedical implants. High speed clock circuits are an integral part of such systems, playing roles such as providing digital processor clocks, or generating wireless carrier signals; this clock generation can often take a large part of a system's power budget. Common techniques to reduce power consumption generally involve reducing the clock speed, and/or complex designs using a large circuit area. This paper proposes an alternative method of clock generation based on driving a high-Q resonator with a periodic chain of impulses. In this way, power consumption is reduced when compared to traditional resonator based designs; this power reduction comes at the cost of increased period jitter. A circuit was designed and laid out in 0.18μm CMOS, and was simulated in order to test the technique. Simulation results suggest that the circuit can achieve a FoM of 4.89GHz/mW, with a peak period jitter of 10.2ps at 2.015GHz, using a model resonator with a Q-factor of 126.