Abstract: The disclosure provides methods and apparatus for simultaneously providing protection to an implantable medical device, such as an extra-cardiac implantable defibrillator (EID), while allowing efficacious therapy delivery via an external defibrillator (e.g., an automated external defibrillator, or AED). Due to the orientation of the electrodes upon application of therapy via, for example, via an AED the structure of the EID essentially blocks therapy delivery. In addition, but for the teaching of this disclosure sensitive circuitry of an EID can be damaged during application of external high voltage therapy thus rendering the EID inoperable. EIDs are disclosed that are entirely implantable subcutaneously with minimal surgical intrusion into the body of the patient and provide distributed cardioversion-defibrillation sense and stimulation electrodes for delivery of cardioversion-defibrillation shock and pacing therapies across the heart when necessary.

Abstract: In power circuit designs, it is sometimes necessary to connect two or more semiconductor power switches in parallel and to simultaneously operate both so that current levels in excess of the rated current handling capability of one of the devices can be conducted. Such operation, however, encounters the problem of current sharing which results from variations in the characteristics of the parallel-connected devices. The method of the present invention obviates the difficulties encountered with current sharing by operating N parallel-connected semiconductor devices one at a time in sequential fashion so that each device conducts an average current equal to the desired average output current divided by N.