Method for controlling power during electrosurgery

• US 4,024,467 A
• Filed: 06/02/1975
• Issued: 05/17/1977
• Est. Priority Date: 07/15/1974
• Status: Expired due to Term

• Current Assignee: MDT Incorporated, Santa Barbara Research Center Goleta CA
• Original Assignee: Sybron Corporation (Envista Holdings Corporation)
• Inventors: Woltosz, Stanley, Andrews, Stephen William
• Primary Examiner(s): Grimm, Siegfried H.
• Application Number:
  US05/582,593
• Time in Patent Office: 715 Days
• Field of Search: 128/303.14, 128/303.17, 128/303.18, 332/14, 332/15, 332/10
• US Class Current: 606/37
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 2018/00642 with feedback, i.e. closed loop control
• CPC Class Codes: A61B 2018/00726 Duty cycle
• CPC Class Codes: A61B 2018/00892 Voltage

Abstract

A control circuit forelectrosurgical units establishes a particular output signal to patient electrodes in response to condition of the patient electrodes. The duty cycle of the output signal is reduced when the patient electrodes are not in contact with the patient so as to prevent unwanted cutting and the duty cycle is increased when both patient electrodes are in contact with the patient so as to maximize the coagulation effect.

The invention includes method of adjusting coagulation power by varying the duty cycle and not the amplitude of the output signal.

Claims

1. The method of controlling, during operating conditions, the average power of a pulse modulated output signal on an electrosurgical unit which comprises the following steps:

selecting the mode of operation;

providing a pulse modulated output signal having a constant amplitude; and

varying the duty cycle of said output signal to obtain the amount of power desired for the particular operating conditions while allowing the amplitude to remain substantially constant.