METHOD AND APPARATUS FOR CAPACITANCE MULTIPLICATION WITHIN A PHASE LOCKED LOOP

摘要

A method and apparatus for capacitance multiplication using two charge pumps. A first charge pump (206) provides a current signal (I216) that is first conducted by a resistor (310) of an RC network and then split into three current paths prior to being conducted by a capacitor of the RC network. A first current path provides current to the capacitor (306) of the RC network from node (320). A second current path multiplies the current conducted by capacitor (306) by a first current multiplication factor. A third current path provides current to a second charge pump (208), which multiplies the current from the first charge pump (206) by a second current multiplication factor that has a fractional value with an inverse magnitude sign relative to the first current multiplication factor. The combination of the second and third current paths effectively multiplies the capacitance magnitude of capacitor (306).