PATIENT ELECTRODE ISOLATION

• US 3,699,389 A
• Filed: 11/19/1970
• Issued: 10/17/1972
• Est. Priority Date: 11/19/1970
• Status: Expired due to Term

• Current Assignee: N/A
• Original Assignee: N/A
• Time in Patent Office: 698 Days
• US Class Current: 361/1
• CPC Class Codes: A61B 5/301 providing electrical separation, e.g. by using isolating transformers or optocouplers
• CPC Class Codes: G01R 15/14 Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
• CPC Class Codes: Y10S 128/908 Patient protection from electric shock

Abstract

A system for preventing the inadvertent electrocution of a surgical patient through accidental coupling of probes and common equipment to ground. Isolation of the patient from ground is obtained through the use of a light emitting diode and a photo transistor in the probe circuit.

Claims

1. A patient electrode isolation circuit for preventing accidental electrocution of a patient comprising first, second, and third input means for receiving signals from electrical equipment as might be used in the treatment of a patient;

a first passive current limiting network connected between the first and second input means, said network being a resistance and a diode, said resistance preventing possible high voltage on the first and second input means from breaking down the diode;

a second passive current limiting network connected between the second and third input means, said network being a resistance and a diode, said resistance preventing possible high voltage on the second and third input means from breaking down the diode;

a first source follower series connected in the first input means;

a second source follower series connected in the third input means;

a third passive current limiting network connected between the input of the first source follower and the second input means, said network being a resistance and a diode, said diode being poled oppositely from the diode in the first passive current limiting network and the resistance preventing any excessive interelectrode leakage in the first source follower from breaking down the diode;

a fourth passive current limiting network connected between the input of the second source follower and the second input means, said network being a resistance and a diode, said diode being poled oppositely from the diode in the second passive current limiting network and the resistance preventing any excessive interelectrode leakage in the second source follower from breaking down the diode;

a differential amplifier connected to receive the outputs of the first and second source followers;

a driver amplifier connected to receive the output of the differential amplifier;

an optical coupler consisting of a diode and a phototransistor connected to the output of the driver; and

output means connected to the phototransistor.