Reconfigurable multi-path injection locked oscillator

A ring oscillator comprising:

• a plurality of delay cells, each of which comprises a primary input lead, a second input lead, and an output lead, wherein the primary input lead and the second input lead in each delay cell are differential leads, wherein the primary input lead of each delay cell comprises a first number of inverter slices, wherein the second input lead of each delay cell comprises a second number of inverter slices,
• wherein the plurality of delay cells are coupled to provide a primary path and a second path, wherein the primary path connects the output lead of each delay cell to a corresponding primary input lead of another delay cell, wherein the second path further connects the output lead of each delay cell coupled to a corresponding second input lead of another delay cell, and wherein the primary path and the second path are configured to generate an oscillating signal with an operating frequency;
• and
• a digital controller coupled to the plurality of delay cells and configured to control a first inverter strength in the primary path and a second inverter strength in the second path, wherein the first and second inverter strengths are determined by the first and second numbers of inverter slices, respectively, and wherein controlling at least one of the first and second inverter strengths tunes the operating frequency.

A method implemented by a ring oscillator that comprises three or more delay cells and a plurality of paths formed by connections among the delay cells, the method comprising:

• receiving reference clock signals at a plurality of differential inputs in each of the delay cells;
• generating an oscillating signal that has an operating frequency and an amplitude;
• and
• calibrating the oscillating signal by digitally controlling at least one inverter strength in at least one of the plurality of paths, wherein controlling the at least one inverter strength tunes the operating frequency, or the amplitude, or both, wherein each path provides an inverter strength determined by a number of inverters in a corresponding differential input lead of each delay cell.