Apparatus for calibrating a charge pump and method therefor

A calibration apparatus for minimizing a main current from a charge pump, said charge pump including a first switch, a second switch, a first current source, and a second current source, wherein said first current source is coupled to said first switch at a first node, said second current source is coupled to said second switch at a second node, and said first switch is coupled to said second switch at a third node, said charge pump outputs said main current through said third node when said first switch and said second switch are enabled, the direction and magnitude of said main current are determined by a first current and a second current, wherein said first current is outputted from said first current source and passes through said first switch, and second current is outputted from said second current source and passes through said second switch, said calibration apparatus comprising:

• a detecting circuit coupled to said charge pump at said third node for outputting a detecting signal according to said direction and magnitude of said main current;
• a current adjusting circuit coupled to said detecting circuit for outputting a calibrating signal according to the polarity and magnitude of the slew rate for said detection signal;
• and
• a calibrating circuit coupled to said charge pump and said current adjusting circuit for adjusting said first current and said second current according to said calibrating signal by outputting a first calibrating current and a second calibrating current to said charge pump.