Electrosurgical radiofrequency generator having regulated voltage across switching device
AssigneeGyrus Medical Limited
InventorColin C. O. Goble
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Abstract
In an electrosurgical generator having a self-tuning oscillator which includes a switching device and a resonant output network connected between the switching device and a supply rail, an oscillator feedback circuit feeds to the switching device a switching control pulse signal for separately switching the switching device to its "on" state whilst the voltage across the device is decreasing, the phase of the "on" point being dynamically variable such that the "on" time of the device is adjusted so as to regulate the amplitude of the voltage thereacross. This allows reverse conduction of the switching device to be avoided, giving improved efficiency.
Claims21
An electrosurgical generator having a radio frequency oscillator comprising at least one switching device, a resonant output network coupled in series with the switching device in a path between power supply rails of opposite polarities, and an oscillator feedback circuit operable to feed to the switching device a switching control pulse signal as an oscillation feedback signal such that the switching device is cyclically switched to its "on" state whilst the voltage across the switching device is decreasing, the phase of the "on" point being dynamically variable such that the "on"-time of the switching device is adjusted to regulate the amplitude of the voltage across the switching device.
Dependencies are inferred from the claim text.