A phase-locked loop circuit, including: an operating circuit for detecting a difference between a reference signal and a feedback oscillating signal to generate a detected result, and generating a first control signal according to the detected result, an auxiliary circuit for generating a second control signal that is asynchronous with the first control signal, and a controllable oscillator coupled to the operating circuit and the auxiliary circuit for generating an output oscillating signal according to the first control signal and the second control signal, wherein the feedback oscillating signal is derived from the output oscillating signal.