Design of variable length ring oscillator for clock synthesis

In this paper, we propose a new architecture of voltage tuning variable length ring oscillator, which can be used in applications such as frequency synthesis, data clock recovery and in phase locked loops (PLLs) based systems. The frequency of the proposed ring oscillator (RO) can be changed dynamically from one frequency to another frequency within a clock period by changing the length of the oscillator electronically. An analog frequency tuning mechanism is also introduced here to make it suitable for applications in PLL based systems. The experimental results from a prototype hardware electronic circuit are presented here to support the validity of the proposed architecture of the RO.