Granted Patent B2

US 7,283,004 · App. 10/561,556 · Granted Oct 16, 2007

Assignee: Freescale Semicondcutor, Inc.

Abstract

Claims (5)

1. A phase locked loop system for integration onto an integrated circuit comprising a charge pump arranged to output a first current over a first charge pump path while a second current is output over a second charge pump path; and a phase locked loop filter characterised in that it comprises only a first capacitor electrically coupled between the first charge pump path and the second charge pump path; and a parallel resistor/capacitor circuit electrically coupled to the second charge pump path with the resistor/capacitor circuit having a second capacitor and a first resistive element; wherein the first capacitor and second capacitor are connected in series to allow a voltage associated with the first capacitor and a voltage associated with the parallel resistor/capacitor circuit to be added together, and an extra pole having a second resistive element and a shunt capacitor coupled, at one end to the second resistive element and at the other end to a reference voltage.

2. A phase locked loop system according to claim 1 , wherein the current flow in the second path is greater than the current flow in the first path to allow a decrease in the capacitance of the phase locked loop filter.

3. A phase locked loop system according to claim 1 , wherein the added voltage is arranged to control a voltage controlled oscillator.

4. An electronic device incorporating a phase locked loop system according to claim 1 .

5. A radiotelephone incorporating a phase locked loop system according to claim 1 .

Assignments (20)

Priority Claims (1)

Continuity (1)