Patent ID: 8237513

Claim:
A voltage controlled oscillator (VCO) for a phase locked loop (PLL), comprising: a startup oscillator; a primary oscillator wherein the startup oscillator has a lower frequency than the primary oscillator, and wherein the startup oscillator and the primary oscillator are each controlled by a control voltage; and a control module connected to the startup oscillator and the primary oscillator, wherein the control module comprises a clock counter, and further comprises a start logic module configured to: send a startup enable signal to the startup oscillator at startup of the PLL, wherein the control voltage is below an oscillator threshold of the startup oscillator and the startup oscillator and primary oscillators are each turned off at startup of the PLL, wherein the control voltage is configured to increase after startup of the PLL, and wherein the startup oscillator is configured to turn on when the control voltage is greater than the oscillator threshold of the startup oscillator after receiving of the startup enable signal by the startup oscillator; wait a predetermined number of clock cycles of the startup oscillator after turning on of the startup oscillator; and when the predetermined number of startup oscillator clock cycles has elapsed, wherein elapsing of the predetermined number of startup oscillator clock cycles is determined by the clock counter: send a disable signal to the startup oscillator such that the startup oscillator turns off; and send a primary enable signal to the primary oscillator such that the primary oscillator is turned on by the control voltage after receiving of the primary enable signal by the primary oscillator.