Patent ID: 8749215

Claim:
An apparatus comprising: a buck-boost switching regulator having buck switches, boost switches, an input terminal, and an output terminal, wherein the buck-boost switching regulator is adapted to operate in a buck mode, boost mode, and bridge mode; and control circuitry that is coupled to at least one of the output terminal and the input terminal and that controls the buck-boost switching regulator with control signals, and wherein the control circuitry adjusts phase relationships between corresponding boost switches and buck switches in bridge mode to reduce ripple current in the buck-boost switching regulator, wherein the buck-boost switching regulator further comprises: a first switch that is coupled between the input terminal and a first switching node; a second switch that is coupled between the first switching node and ground; an inductor that is coupled between the first switching node and a second switching node; a third switch that is coupled between the second switching node and ground; and a fourth switch that is coupled between the second switching node and the output terminal wherein the control circuitry provides a first, second, third, and fourth control signals for the first, second, third, and fourth switches, respectively wherein the control circuitry adjusts the third control signal to have an on-time for the third switch that is centered to an off-time for the first switch, wherein an inductor current of the inductor coupled to the first and third switches is substantially constant wherein the control circuitry adjusts the third control signal; wherein the control circuitry further comprises: a processor; a voltage divider that is coupled to the output terminal; and an error amplifier that receives a reference voltage and that is coupled to the voltage divider and the processor.