Built-In Self Test device and Phase-Locked Loops including the same, Built-In Self Test scheme and Storage medium storing the same

摘要

A self test device built in a phase-locked loop, the package locked loop including the same, a testing method thereof, and a storage medium storing the same are provided to test an internal defect with small hardware overhead by using only digital signal inside the phase-locked loop by calculating a hamming distance. A built-in self test device(100) of a phase locked loop includes a first shift detection unit(110a,110b,110c), and a second shift detection unit(120a,120b,120c) and a shift frequency calculation unit(150). The first shift detection unit receives an original output signal of a voltage controlled oscillator of the phase-locked loop and the division signals dividing the frequency of the original output signal from a frequency divider and outputs the level shift between the signals in a digital type. The second shift detection unit. The second shift detection unit outputs the level shift in the digital type by comparing the level shift outputted from the first shift detection unit and the level shift previously outputted from the first shift detection unit. The shift calculation unit calculates the shift frequency through the output value of the second shift detection unit and determines the defect of the phase-locked loop.