An implantable defibrillation circuit can include an output circuit. The output circuit can include a first switch configured to controllably connect a first supply node to a first output node, a second switch configured to controllably connect a second supply node to the first output node through a first rectifier, and the second switch can be configured to inhibit the first switch from connecting the first supply node to the first output node when the second supply node is connected to the first output node through the second switch. In an example, the first and second switches can include insulated gate bipolar transistors.
