Interleaved vco with balanced feedforward

An oscillator system comprising:

• a plurality of delay paths including at least first and second delay paths, wherein the plurality of delay paths are connected to form a loop so as to sustain oscillation in the loop;
• and
• at least one feedforward path coupled in parallel with one or more delay paths for receiving an output signal of the first delay path and outputting a feedforward signal to the second delay path, wherein the loop contains the one or more delay paths coupled between the first and second delay paths,
• wherein the at least one feedforward path comprises an AC path comprising:
• a first parallel section having a plurality of parallel branches and configured for receiving one or more control signals, wherein the plurality of parallel branches is selectively conducted in response to the one or more control signals;
• and
• a second parallel section coupled in series with the first parallel section and configured to remain conducting when any of the plurality of parallel branches becomes conducting, wherein the first and second parallel sections are configured to transmit an AC feedforward signal when conducting.

A phase-locked loop comprising:

• a phase-frequency detector generating an error signal and one or more control signals;
• a charge pump coupled to the phase-frequency detector for receiving the error signal;
• a loop filter coupled to the charge pump and configured for generating a voltage output Vc;
• a voltage-controlled oscillator coupled to the phase-frequency detector and the loop filter for receiving the one or more control signals and the voltage output Vc,
• wherein the voltage controlled oscillator has a plurality of delay paths coupled in a loop and an AC feedforward path coupled in parallel with one or more delay paths in the loop, the AC feedforward path comprising:
• a first parallel section having a plurality of parallel branches, wherein the plurality of parallel branches is selectively conducted in response to the one or more control signals;
• and
• a second parallel section coupled in series with the first parallel section and configured to remain conducting when any of the plurality of parallel branches becomes conducting, wherein the first and second parallel sections are configured to transmit an AC feedforward signal when conducting.