Patent ID: 8723489

Claim:
A buck-boost circuit comprising: a first voltage bus; a second voltage bus; at least one buck-boost converter coupled between the first voltage bus and the second voltage bus; wherein: the buck-boost converter is configured to generate a voltage on the first voltage bus responsive to a voltage on the second voltage bus in a first mode of operation during use; the buck-boost converter is configured to generate the voltage on the second voltage bus responsive to the voltage on the first voltage bus in a second mode of operation during use; the first mode of operation is a boost mode; the second mode of operation is a buck mode; and the buck-boost converter comprises: an inductor; a first node; a first switch in parallel with a first power diode between the second voltage bus and the first node, wherein the first switch is configured to be closed in the buck mode and the first power diode is distinct from the first switch; and a second switch in parallel with a second power diode between the first node and ground, wherein the second switch is configured to be closed in the boost mode and the second power diode is distinct from the second switch; and a monitoring circuit configured to: monitor a voltage across the inductor; and detect a failure of the buck-boost converter, wherein the failure of the buck-boost converter is indicated when a peak voltage across the inductor is zero.