Patent ID: 7248125
Filing Date: 2007-07-24
Classification: H03K

Abstract:
1. An even number phase ring oscillator having at least eight, equally spaced phases, comprising: at least eight stages, defining at least four pairs of stages, with each pair including a first stage and an associated second stage, the first stages being arranged such that an output of a first stage defines a primary input of another first stage, with the output of the first stage of the last pair defining the primary input of the second stage of the first pair, and the second stages being arranged such that an output of a second stage defines a primary input of an another second stage, with the output of the second stage of the last pair crossing over the output of the first stage of the last pair and defining a primary input of the first stage of the first pair, thereby defining a closed loop, a first cross connection between an output of each first stage of each pair and an input of each associated second stage, and a second cross connection between an input of each first stage of each pair and an output of each associated second stage, thereby ensuring that the oscillator provides an odd number inversions around the loop, and a feed forward connection between an input of each (n) stage and an output of each (n+2) stage, with (n) being any one of the stages, so as to provide a feed forward input to each stage to increase a speed at which an output of each stage switches, wherein two bias inputs are provided to control a strength of N pull-down and P pull-up of each stage.