1020000036734 is referenced by 9 patents.
PURPOSE: A PLL(Phase Locked Loop) with a differential frequency current converter is provided to perform a tracking operation within a short time by detecting a frequency difference as well as a phase difference. CONSTITUTION: A frequency demultiplier(100) received a feedback output signal and divides the feedback output signal into arbitrary frequencies. A phase comparator(110) receives input signals from an outside and the feedback signal from the frequency demultiplier(100) and detects a phase difference. A charge pump(120) receives the phase difference from the phase comparator(110) and performs a charge operation or a discharge operation. A differential frequency current converter(200) receives the input signal and the feedback signal and compares a frequency of the input signal and a frequency of the feedback signal. A loop filter(130) receives an output signal from the differential frequency current converter(200) and removes a frequency component from the output signal of the charge pump(120). A voltage controlled oscillator(140) generates an output frequency proportional to the loop filter(130).