Patent ID: 8289088

Claim:
An inverting difference oscillator circuit, comprising: N stages, wherein each stage includes: a circuit element path that includes at least one inverting circuit element; a bypass path; and a selection circuit, wherein one input of the selection circuit is coupled to the circuit element path and another input of the selection circuit is coupled to the bypass path, and wherein an output of the selection circuit is coupled to the bypass path and to the circuit element path in a next stage; and wherein an output of a selection circuit in a last stage is coupled to the bypass path and to the circuit element path that are coupled to the inputs of the selection circuit in a first stage to form a circuit path loop; and N control signals, wherein each control signal is coupled to a separate selection circuit, and wherein the control signals configure the inverting difference oscillator as a ring oscillator by forwarding the output from the circuit element path in selected stages and forwarding the bypass path in any other stages to configure the circuit path loop to include an odd number of inverting circuit elements; wherein one or more of the stages includes a pulse generator circuit coupled to a disable signal, wherein, when the disable signal is asserted, the pulse generator circuit is configured so that none of a given set of internal inverting circuit elements in the pulse generator circuit is included as inverting circuit elements on the circuit element path in the stage, and wherein, when the disable signal is deasserted, the pulse generator circuit is configured so that at least some of the given set of internal inverting circuit elements in the pulse generator circuit are included as inverting circuit elements on the circuit element path in the stage.