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Abstract

A solid-state defibrillation circuit for applying a multiphasic defibrillation pulse to a patient is disclosed. The circuit eliminates the need for a mechanical relay, and provides for a current limiting circuit for limiting leakage currents that would otherwise flow to the patient from the solid-state components, and for preventing the short-circuiting of a defibrillation pulse from a second defibrillator. In one embodiment, the output circuit of the defibrillator comprises an H-bridge, and the current limiting circuit comprises a plurality of resistors coupled in parallel with each of the legs of the H-bridge. The plurality of resistors allow current flow which reduces the voltage potential across the patient that is caused by the leakage currents through the output circuit. The current limiting circuit also includes a shunt resistor for shunting leakage currents away from the patient. The current limiting circuit also includes a non-linear element, such as an MOV or tranzorb in series with the output of the defibrillation circuit for limiting the leakage currents. The current limiting circuit also includes a diode coupled in series with one of the solid-state switches of the output circuit, for helping prevent voltage breakdown across the switches of the output circuit when an external energy shock is applied from an outside source, such as from a second defibrillator.

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First Claim