Patent ID: 7180378
Filing Date: 2007-02-20
Classification: H03K

Abstract:
1. A tunable ring oscillator having a delay circuit, the delay circuit comprising: a first fixed time delay operable to receive a delay signal input and to generate a first delayed signal; fine tuning circuitry for mixing the delay signal input and the first delayed signal as a function of a fine tuning input; a fast path delay operable to apply a second fixed time delay to an output signal of the fine tuning circuitry to generate a second delayed output; a slow path delay operable to apply a third fixed time delay to the output signal of the fine tuning circuitry to generate a third delayed output; and coarse tuning circuitry for setting one of a minimum time delay or a maximum time delay as a function of a coarse tuning input; wherein the coarse tuning circuitry is operable to set one of the minimum time delay or the maximum time delay by mixing the second delayed output signal and the third delayed output signal as a function of the coarse tuning input.