Patent ID: 8018212

Claim:
A buck-boost regulator for converting an input voltage to an output voltage, comprising: an inductor having a first end and a second end; an error circuit which determines an error of the output voltage and which provides an error voltage indicative thereof; a buck switching circuit which switches said first end of said inductor between the input voltage and ground as controlled by a buck pulse width modulation signal; a buck ripple circuit which replicates ripple current through said inductor based on said buck pulse width modulation signal and which provides a buck ripple voltage indicative thereof; a buck hysteretic comparator circuit which develops said buck pulse width modulation signal based on comparing said buck ripple voltage within a buck window voltage range between said error voltage and said error voltage combined with a buck window voltage; a boost switching circuit which switches said second end of said inductor between the output voltage and ground as controlled by a boost pulse width modulation signal; a boost ripple circuit which replicates ripple current through said inductor based on said boost pulse width modulation signal and which provides a boost ripple voltage indicative thereof; and a boost hysteretic comparator circuit which develops said boost pulse width modulation signal based on comparing said boost ripple voltage within a boost window voltage range between said error voltage and said error voltage combined with a boost window voltage.