Patent ID: 8081037

Claim:
An apparatus comprising a ring oscillator and a loop controller, the ring oscillator comprising: a first ring loop comprising a plurality of series coupled delay cells; and at least one additional ring loop comprising a plurality of series coupled delay cells, the at least one additional ring loop being coupled to the first ring loop by one or more common delay cells shared between the first ring loop and the at least one additional ring loops, and an enable cell configured to activate or deactivate the additional ring loop based on a corresponding control signal, wherein the loop controller is configured to dynamically control the number of active additional ring loops by individually asserting or de-asserting each control signal, and wherein the first ring loop and the at least one additional ring loop are configured to be active concurrently when the at least one additional ring loop is activated, and the first ring loop is configured to be active independently of the at least one additional ring loop when the at least one additional ring loop is deactivated.