Patent ID: 8090335

Claim:
A method of operating a phase locked loop (PLL), comprising: disconnecting a phase correction device used to correct errors between a local oscillator (LO) signal and a reference signal to perform a calibration function during an open loop operation of the PLL to set a frequency of the LO signal, the calibration function including, comparing the LO signal and the reference signal to obtain a relative frequency difference between the LO signal and the reference signal; calculating a step size signal based upon the relative frequency difference; and adjusting a control voltage in proportion to the relative frequency difference based upon the step size signal to adaptively adjust the frequency of the LO signal to be within a programmable range of a frequency of the reference signal, wherein the step size signal is adaptively adjusted to perform the calibration function; reconnecting the phase correction device after completion of the calibration function within the programmable range to allow the PLL to correct errors between the LO signal and the reference signal; monitoring the LO signal and the reference signal; and disconnecting the phase correction device to perform the calibration function during another open loop operation of the PLL if an unlocked state of the LO signal is detected based upon the programmable range.