Stable Equilibrium State Analysis of the Differential Ring Oscillator with Even Number of Stages
Zhang Hui①② Yang Hai-gang① Zhou Fa-biao①② Liu Fei① Gao Tong-qiang①
①(Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China) ②(Graduate University of Chinese Academy of Sciences, Beijing 100049, China)
Abstract:The start-up conditions for differential oscillator with an even number of stages are analyzed in this paper. Compared with those that have an odd number of stages, such oscillators may have two stable equilibrium states besides an astable equilibrium state in which the circuits can start to oscillate. To avoid the risk of possible latching up into the stable states, an additional start-up circuit technique is proposed. The proposed circuit should also reduce the start-up time. The theory is further confirmed with the design and fabrication of three kinds of differential ring Voltage-Controlled Oscillator (VCO), a 3-stage one, 4-stage ones with and without the start-up circuit based on a 0.13 μm standard CMOS process. The measurement results show that the 3-stage one and the 4-stage one with the start-up circuit have the correct output oscillation signals, but the 4-stage without the start-up circuit has nothing to output.
张辉, 杨海钢, 周发标, 刘飞, 高同强. 偶数级差分环形振荡器的稳定平衡态分析[J]. 电子与信息学报, 2011, 33(8): 1969-1974.
Zhang Hui, Yang Hai-Gang, Zhou Fa-Biao, Liu Fei, Gao Tong-Qiang. Stable Equilibrium State Analysis of the Differential Ring Oscillator with Even Number of Stages. , 2011, 33(8): 1969-1974.