Physio-control Manufacturing Corporation

Gus H White

Scott Owen Schweizer

Aaron Huynh

A method and apparatus for providing automatic power switching in a portable external defibrillator is disclosed. The power supply switching circuit includes a plurality of power supply ports for receiving power sources such as batteries and external power sources. The power supply switching circuit works with both batteries that include monitoring devices (smart batteries) and batteries that do not include monitoring devices (dumb batteries). The power supply switching circuit also includes microprocessor controllable switches for selectively coupling the power supply ports to the output of the power supply switching circuit, and a microprocessor for controlling the switches and for monitoring the power supply ports. Resident in the microprocessor is a control program for controlling the switching and monitoring operations. The control program uses data received from the power sources to select the best available power source to be used as the output for the power supply switching circuit. The control program has routines for monitoring both smart and dumb batteries, and the power supply switching circuit can thus use a combination of smart and dumb batteries. In one test, a load is placed on a battery and then the output voltage of the battery is measured. A user of the defibrillator is kept completely informed as to the status of the power sources through information that is provided from a display or auditory signals. For smart batteries, a fuel gauge is provided on the display. Warnings are provided when a battery needs changing, or when other user action is required.

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Redmond, WA, United States of America

Gus H White