Patent ID: 7439784
Filing Date: 2008-10-21
Classification: H03L

Abstract:
1. A charge pump circuit, comprising: a first current providing circuit, for providing a current source to the charge pump circuit; a second current providing circuit, for providing a current sink to the charge pump circuit; a dummy current path, coupled between the first current providing circuit and the second current providing circuit, comprising a first switch element, a second switch element, and a first junction node between the first switch element and the second switch element; a first capacitor, coupled to the first junction node; a normal current path, coupled between the first current providing circuit and the second current providing circuit, comprising a third switch element, a fourth switch element, and a second junction node between the third switch element and the fourth switch element; a second capacitor, coupled to the second junction node; a voltage follower, coupled to the second junction node of the normal current path; a switch, coupled between an output node of the voltage follower and the first junction node of the dummy current path; wherein when the switch is switched on in a first period, a first voltage is at the first junction node and the second junction node, and when the switch is switched off in a second period, the first voltage is at the second junction node and a second voltage is at the first junction node; and a calibration circuit, coupled to the first junction node of the dummy current path and the output node of the voltage follower, for comparing the first voltage and the second voltage to balance a current mismatch between the current source and the current sink, the calibration circuit comprising: