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Electrosurgery system and instrument

  • US 6,547,786 B1
  • Filed: 05/18/2000
  • Issued: 04/15/2003
  • Est. Priority Date: 05/21/1999
  • Status: Expired due to Fees
First Claim
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1. An electrosurgery system comprising a generator which includes a source of radio frequency (r.f.) energy for feeding to a treatment electrode of an electrosurgical instrument, the generator comprising:

  • a circuit for sensing thermionic emission from the treatment electrode, the sensing circuit having an input stage arranged substantially to remove r.f. signals at an operating frequency or frequencies of the generator to yield an averaged representation of r.f. output of the generator, and a detection stage coupled to the input stage to receive the averaged representation, wherein the generator is arranged to generate a modulated r.f. output for feeding to the treatment electrode of the electrosurgical instrument, and the sensing circuit is arranged such that substantial removal of the r.f. signals at the generator operating frequency results in an averaged signal being fed to the detection stage which produces a sensing circuit signal as a measure of an amplitude of the averaged signal;

    wherein the sensing circuit input stage comprises a filter having a passband including the frequency of the modulation but excluding the generator operating frequency, the averaged signal being an a.c. signal having a frequency equal to the modulation frequency; and

    wherein the generator has an output stage having a pair of output lines coupled to respective generator output terminals, each output line having a series-connected isolation capacitor, and a series inductor in one of the output lines between the respective isolating capacitor and output terminal, the inductor being coupled to the input stage of the sensing circuit.

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