PHASE-LOCKED LOOP CIRCUITRY USING CHARGE PUMPS WITH CURRENT MIRROR CIRCUITRY

摘要

A system and method for performing phase-locked loop is disclosed. The systemincludes phase frequency detector circuitry, charge pump circuitry (225)having first current mirror circuitry (305) and second current mirrorcircuitry (310), loop filter circuitry, and voltage controlled oscillatorcircuitry. The phase frequency detector circuitry generates an up signal and adown signal based on the phase difference of an input signal and a feedbacksignal. The first and second current miroir circuitries (305, 310) replicate arefrence current (340). A biasing circuitry (315) is configured to generate avoltage for the first current miroir circuitry (310) based on a voltage biasto the second current mirror circuitry (310) based on a voltage for the firstcurrent mirror circuitry and the voltage of the circuitries to accuratelyreplicate the reference current (340) at low power thereby providing currentpulses of equal magnitude at low currents.