Patent ID: 6922097

Claim:
A dual two-phase charge pump comprising: a first transfer capacitor; a second transfer capacitor; a first output capacitor, between a first output and a ground; a second output capacitor, between a second output and the ground; positive phase control logic for charging the first transfer capacitor during a second positive phase, and for coupling the first transfer capacitor to the first output capacitor during a first positive phase to generate a boosted positive voltage on the first output; negative phase control logic for charging the first transfer capacitor during a second negative phase, and for coupling the first transfer capacitor to the second transfer capacitor during a first negative phase, and for coupling the second transfer capacitor to the second output capacitor during the second negative phase to generate a boosted negative voltage on the second output; a first comparator, for comparing the first output to a first reference voltage to generate a first activation signal to the positive phase control logic when a voltage of the first output is below the first reference voltage; and a second comparator, for comparing the second output to a second reference voltage to generate a second activation signal to the negative phase control logic when a magnitude of a voltage of the second output is less than the second reference voltage, whereby the boosted negative voltage and the boosted positive voltage are generated by separate output capacitors and whereby charge transfer using the positive phase control logic and the negative phase control logic is separately activated by the voltage comparisons.