Patent ID: 8575966

Claim:
A method of operating a charge pump of a phase-lock assistant circuit, the method comprising: determining a first relative timing relationship of a phase of a data signal during a current clock cycle to a phase of a first phase clock during the current clock cycle; determining a second relative timing relationship of the phase of the data signal during the current clock cycle to a phase of a second phase clock during the current clock cycle, the first and second phase clocks having a 45° phase difference; generating an up signal and a down signal in response to the first relative timing relationship, and the second relative timing relationship, a third relative timing relationship of a phase of the data signal during a previous clock cycle to a phase of the first phase clock during the previous clock cycle, and a fourth relative timing relationship of the phase of the data signal during the previous clock cycle to a phase of the second phase clock during the previous clock cycle; and driving the charge pump circuit according to the up signal and the down signal.