PHASE-LOCKED LOOP SYSTEMS AND METHODS

摘要

Improved common mode feedback techniques are provided for charge pumps, phase-locked loops (PLLs), and other circuits. For example, in accordance with an embodiment of the present invention, a circuit includes a loop filter having first and second loop filter nodes. An amplifier is provided having first and second differential inputs respectively coupled to the first and second loop filter nodes. A first current source is coupled to the first loop filter node and a second current source is coupled to the second loop filter node. The first and second current sources are adapted to continuously adjust a common mode voltage of the loop filter nodes.