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 system includes phase frequency detector circuitry, charge pump circuitry (225) having first current mirror circuitry (305) and second current mirror circuitry (310), loop filter circuitry, and voltage controlled oscillator circuitry. The phase frequency detector circuitry generates an up signal and a down signal based on the phase difference of an input signal and a feedback signal. The first and second current mirror circuitries (305, 310) replicate a reference current (340). A biasing circuitry (315) is configured to generate a voltage for the first current mirror circuitry (310) based on a voltage basis to the second current mirror circuitry (310) based on a voltage for the first current mirror circuitry and the voltage of the circuitries to accurately replicate the reference current (340) at low power thereby providing current pulses of equal magnitude at low currents.