Patent ID: 7688131
Filing Date: 2010-03-30
Classification: H02M

Abstract:
1. A charge pump circuit, for generating a first output voltage and a second output voltage according to an input voltage, comprising: a pump unit comprising at least an internal capacitor, a first terminal, a second terminal, a third terminal, and a fourth terminal, wherein the first terminal is coupled to the input voltage, the second terminal is coupled to a first voltage so as to charge the internal capacitor with the input voltage and the first voltage during a first period, and allow the internal capacitor to provide the first output voltage to the fourth terminal during a second period and a third period in accordance with a voltage level of the third terminal; a first switch, comprising a first terminal coupled to a second voltage, and a second terminal coupled to the third terminal of the pump unit, wherein the first switch is maintained off during the first period, and maintained on during the second period and the third period; a second switch, comprising a first terminal coupled to the fourth terminal of the pump unit, and a second terminal, wherein the second switch is maintained off during the first period, and maintained on during the second period and the third period; a third switch, comprising a first terminal coupled to the second terminal of the second switch, and a second terminal, wherein the third switch is maintained on during the first period and the second period, and maintained off during the third period, wherein the first terminal of the third switch is also coupled to the output terminal of the first output voltage; a fourth switch, comprising a first terminal coupled to a third voltage, and a second terminal, wherein the fourth switch is maintained on during the first period and the second period, and maintained off during the third period; a fifth switch, comprising a first terminal coupled to a fourth voltage, and a second terminal, wherein the fifth switch is maintained off during the first period and the second period, and maintained on during the third period; a fly capacitor, comprising a first terminal and a second terminal, wherein the first terminal of the fly capacitor is coupled to the second terminal of the third switch and the second switch of the fifth switch, the second terminal of the fly capacitor is coupled to the second terminal of the fourth switch, wherein the second terminal of the fly capacitor is coupled to the third voltage during the second period, for charging the fly capacitor with the first output voltage and the third voltage; the fly capacitor provides the second output voltage to the second terminal of the fly capacitor in accordance with a voltage level of the fourth voltage during the third period; and the second terminal of the fly capacitor is coupled to the third voltage, so as to provide the first output voltage to the first terminal of the fly capacitor during the first period in accordance with a voltage level of the third voltage; and a sixth switch, comprising a first terminal coupled to the second terminal of the fly capacitor, and a second terminal coupled to provide the second output voltage, wherein the sixth switch is maintained off during the first period and the second period, and maintained on during the third period.