Electrosurgical generator and system

An electrosurgical system comprising:

• an electrosurgical instrument including at least three electrodes,
• a generator system for generating radio frequency (RF) power, the generator system comprising:
• first and second sources of RF output power operating at different frequencies, the first source of RF power delivering a cutting RF waveform, and the second source of RF power delivering a second coagulating RF waveform,
• a controller for controlling the generator to deliver the cuffing RF waveform or the coagulating RF waveform, and, in a combined mode, to deliver both first and second RF waveforms, and
• an output stage for feeding the waveforms to the at least three electrodes of the electrosurgical instrument, such that, in the combined mode, the cutting RF waveform is delivered between a first pair of the at least three electrodes, and the coagulating RF waveform is delivered between a second pair of the at least three electrodes.

An electrosurgical system comprising:

• an electrosurgical instrument including at least three electrodes,
• a generator system for generating radio frequency (RF) power, the generator system comprising:
• a common power supply,
• a first RF oscillator operating at a first frequency,
• a second RF oscillator operating at a second frequency,
• a controller for controlling the generator to deliver a cutting RF waveform power signal from the first RF oscillator or a coagulating RF waveform power signal from the second RF oscillator, and, in a combined mode, to deliver both the cutting and coagulating RF waveform power signals from the first and second RF oscillators, and
• a switch for selecting the cutting RF waveform power signal from the first oscillator or the RF coagulating waveform power signal from the second oscillator, the switch, in the combined mode, being operated repeatedly at a predetermined rate to produce a blended output power signal, the selected output power signal being produced across a pair of output connections of the switch,
• a pair of tuned circuits, each circuit being tuned to a different one of the oscillator frequencies, outputs of the tuned circuits being coupled to respective electrodes of the electrosurgical instrument, such that the cutting signal from the first oscillator is fed to a cutting electrode and a common electrode of the electrosurgical instrument, and the coagulation signal from the second oscillator is fed to a coagulation electrode and the common electrode of the electrosurgical instrument.

An electrosurgical system comprising:

• a generator system for generating radio frequency (RF) power, and an electrosurgical instrument including at least three electrodes, the generator system comprising:
• a first RF source circuit comprising a first RF oscillator operating at a first frequency, a first power supply, a first controller, a first voltage threshold detector and a first on time control circuit, the first voltage threshold detector being set such that first output connections from the first RF source circuit provide an output power signal having a cutting RF waveform,
• a second RF source circuit comprising a second RF oscillator operating at a second frequency, a second power supply, a second controller, a second voltage threshold detector, and a second on time control circuit, the second voltage threshold detector being set such that second output connections from the second RF source circuit provide an output power signal having a coagulating RF waveform, and
• an output stage connected to each of the first and second source circuits,
• the first output connections from the first source circuit being connected to a first pair of input connections of the output stage, and the second output connections from the second source circuit being connected to a second pair of input connections of the output stage, respectively, one of each of the first and second input connections both being connected to a first output connection of the output stage, the other of the first input connections being connected to a second output connection of the output stage, and the other of the second input connections being connected to a third output connection of the output stage,
• wherein the cutting RF waveform from the first source circuit is delivered between the first and second output connections of the output stage, and hence to one pair of electrodes on the electrosurgical instrument, and wherein the coagulating RF waveform from the second source circuit is delivered between the first and third output connections of the output stage, and hence to a different pair of electrodes of the instrument so that the electrosurgical instrument is able simultaneously to cut and coagulate tissue using the two different frequency waveforms.

An electrosurgical system comprising:

• an electrosurgical instrument including at least three electrodes,
• a generator system for generating radio frequency (RF) power, the generator system comprising:
• a power supply,
• a first oscillator operating at a first RF frequency,
• a second oscillator operating at a second RF frequency,
• a controller for controlling the generator to deliver a cutting RF waveform from the first oscillator or a coagulating RF waveform from the second oscillator, and, in a combined mode, to deliver both the cutting and coagulating RF waveforms from the first and second oscillators, and
• an output stage comprising at least one pair of push-pull RF switches, each switch being connected to an output of one of the first and second oscillators, and a pair of tuned circuits, each circuit being tuned to either the first oscillator's frequency or the second oscillator's frequency, outputs of the tuned circuits being coupled to respective electrodes of the electrosurgical instrument, such that the cutting signal from the first oscillator is fed to a cutting electrode and a common electrode of the electrosurgical instrument, and the coagulation signal from the second oscillator is fed to a coagulation electrode and the common electrode of the electrosurgical instrument.