High frequency power source

A method for controlling an electrosurgical RF power generator for performing electrosurgical tissue cutting at a patient's site, comprising:

• a. directly contacting tissue at the patient's site with an exposed conductive length of a tissue cutting electrode while a return electrode is in contact with the patient's tissue at a location that is remote from the patient's site, each of the tissue cutting electrode and the return electrode being in electrical communication with the electrosurgical RF power generator;
• b. generating RF energy as a waveform within the electrosurgical RF power generator and gating the RF energy to generate gated RF energy;
• c. delivering the gated RF energy from the electrosurgical RF power generator to the tissue cutting electrode so as to pass an electrical current from the exposed conductive length of the tissue cutting electrode to tissue in contact with the exposed conductive length of the tissue cutting electrode to form a steam layer between the tissue cutting electrode and the tissue by tissue desiccation and generate a conductive plasma along the exposed conductive length, and with the onset of the steam layer continued desiccation and cutting of the tissue is effected;
• and
• d. regulating the electrosurgical RF power generator to maintain formation of the steam layer by adjusting a gain of a voltage controlled amplifier in the electrosurgical RF power generator based at least in part on a DC potential generated across a tool/tissue boundary of the electrosurgical cutting tool and the tissue at the patient's site.

A method for controlling an electrosurgical RF power generator for performing electrosurgical tissue cutting at a surgical site on a patient, comprising:

• a. contacting tissue at the surgical site with an exposed conductive length of a tissue cutting electrode while a return electrode is in contact with the patient's tissue at a location that is remote from the surgical site, each of the tissue cutting electrode and the return electrode being in electrical communication with the electrosurgical RF power generator;
• b. generating RF energy as a waveform within the electrosurgical RF power generator and gating the RF energy to generate gated RF energy;
• c. delivering the gated RF energy from the electrosurgical RF power generator to the tissue cutting electrode so as to pass an electrical current from the exposed conductive length of the tissue cutting electrode to tissue in contact with the exposed conductive length of the tissue cutting electrode to form a steam layer between the tissue cutting electrode and the tissue by tissue desiccation and generate a conductive plasma along the exposed conductive length, and with the onset of the steam layer continued desiccation and cutting of the tissue is effected;
• and
• d. regulating the electrosurgical RF power generator to maintain formation of the steam layer by adjusting a gain of a voltage controlled amplifier in the electrosurgical RF power generator based at least in part on a DC potential generated across a tool/tissue boundary of the electrosurgical cutting tool and the tissue at the patient's site.