Patent ID: 7282985

Claim:
A charge pump, for producing at least a first output voltage and a second output voltage according to an input voltage, the charge pump comprising: a pump unit, comprising at least an internal capacitor, a first end, a second end, a third end, a fourth end, a fifth end and a sixth end, wherein the first end is coupled to the input voltage, the second end is coupled to a first voltage, for the input voltage and the first voltage to charge the internal capacitor during a first period, for the internal capacitor to provide the fourth end with the first output voltage based on a level of the third end during a second period, for the internal capacitor to provide the sixth end with the second output voltage based on a level of the fifth end during a third period; a first switch, wherein one end thereof is coupled to a second voltage and another end thereof is coupled to the third end of the pump unit, for connecting the second voltage to the third end of the pump unit during the second period, so the level of the third end of the pump unit is the second voltage, when the first switch is turned on; a second switch, wherein a first end thereof is coupled to the fourth end of the pump unit, for connecting the first output voltage from the fourth end of the pump unit to a second end of the second switch during the second period; a third switch, wherein one end thereof is coupled to a third voltage and another end thereof is coupled to the fifth end of the pump unit, for connecting the third voltage to the fifth end of the pump unit during the third period, so the level of the fifth end of the pump unit is the third voltage, when the third switch is turned on; and a fourth switch, wherein a first end thereof is coupled to the sixth end of the pump unit, for connecting the second output voltage from the sixth end of the pump unit to a second end of the fourth switch during the third period, wherein during a fourth period, the internal capacitor of the pump unit provides the fourth end with a third output voltage based on the level of the third end, and the charge pump further comprises: a fifth switch, wherein one end thereof is coupled to a fourth voltage and another end thereof is coupled to the third end of the pump unit for connecting the fourth voltage to the third end of the pump unit during the fourth period, so the level of time third end of the pump unit is the fourth voltage, when the fifth switch is turned on; and a sixth switch, wherein a first end thereof is coupled to the fourth end of the pump unit for connecting the third output voltage from the fourth end of the pump unit to a second end of the sixth switch during the fourth period.