Patent ID: 8000117

Claim:
A buck boost voltage converter circuit, comprising: a capacitor pump circuit for boosting an input voltage in a first mode of operation when an input voltage is below a desired level; and a buck converter circuit for providing the output voltage responsive to the boosted input voltage from the capacitor pump circuit in the first mode of operation and for providing the output voltage responsive to the input voltage in a second mode of operation when the input voltage is above the desired level wherein the buck converter circuit further comprises: a high side switching transistor connected to receive either the input voltage or the boosted input voltage; a low side switching transistor connected between the high side switching transistor and ground; an inductor connected between the high side switching transistor and an output node; and an output capacitor connected between the output node and ground; wherein the capacitor pump circuit is operated in unison with the high side switching transistor to provide twice the input voltage when the high-side switching transistor is turned on in the first mode of operation and to provide the input voltage when the high-side switching transistor is turned off in the first mode of operation.