05372596 is referenced by 382 patents and cites 5 patents.

Apparatus and method find leakage due to tissue load or transients and has active and return electrodes for RF energy sensed by transformers for a circuit that finds leakage at more than two thousand times per second or a frequency dependent on the phase shift between voltage and current. Software and feedback manage V.sub.rms to reduce the voltage or increase the crest factor, which is V.sub.rms divided by peak voltage, by pulse width modulation of the RF drive. Voltage and current phase shift changes, angle .theta., are compared to a threshold, and when greater, the frequency at which the differences between the active and return current signals are examined is increased. The differences between the active and return currents are examined and when greater than maximum leakage while in coagulation mode, the RF drive pulse width is reduced to maintain voltage wave peaks at a preset value and reduce V.sub.rms thereby reducing leakage to the allowable maximum. Reducing the duty cycle or the pulse width of the output wave increases the crest factor. When the differences between active and return currents are greater than a maximum for leakage while in cut or bipolar mode, the V.sub.rms is reduced to limit leakage to a maximum level. When the phase angle .theta. is less than a threshold, the frequency with which leakage is examined is reduced.

Title
Apparatus for leakage control and method for its use
Application Number
8/97737
Publication Number
5372596
Application Date
July 27, 1993
Publication Date
December 13, 1994
Inventor
William G Paterson
Longmont
CO, US
Michael S Klicek
Boulder
CO, US
Agent
Aaron Passman
Lawrence C Akers
Peter C Richardson
Assignee
Valleylab
CO, US
IPC
A61B 17/39
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