Patent ID: 11909409

Abstract:
A Phase Locked Loop (PLL) with reduced jitter includes: a phase detector, for comparing the phases of a reference clock and feedback clock to generate up and down control signals; a Voltage Controlled Oscillator (VCO) for generating an oscillation signal; an output divider, for dividing the oscillation signal to generate an output clock; a fractional feedback divider for receiving the oscillation signal and performing frequency division on the oscillation signal according to a modulated sequence to generate a modulated clock; and a divider coupled in series to the fractional feedback divider, for dividing the modulated clock of the fractional feedback divider by a fixed modulus to generate a divided clock. A frequency of the modulated clock of the fractional feedback divider is an integer multiple of the frequency of the divided clock, and one of the modulated clock and divided clock is used as the feedback clock.