Charge pump, phase frequency detector and charge pump methods

A phase/frequency detector (PFD) for controlling a charge pump, the PFD received a reference clock signal and an input clock signal, and the PFD characterized in that:

• when a phase information between the reference clock signal and the input clock signal indicates a leading phase, the PFD controls the charge pump to conduct electrical charges into/from an output terminal of the charge pump at a predetermined rate;
• when the phase information indicates the lagging phase, the PFD controls the charge pump to conduct the electrical charges from/into the output terminal of the charge pump at the predetermined rate;
• and when the phase information indicates a transition between the leading phase and the lagging phase, the PFD controls the charge pump to conduct a predetermined quantity of electrical charges via the output terminal.