Power level transitioning in a surgical instrument

摘要

An electrosurgical system and method are disclosed. The system includes an electrosurgical generator adapted to supply electrosurgical energy to tissue. The generator is further adapted to supply an electrosurgical signal at a variable power level. The generator includes sensor circuitry adapted to sense tissue impedance and/or an electrosurgical signal zero crossing. The generator also includes a controller, which may include a microprocessor, that is adapted to receive a tissue impedance signal and/or a waveform zero crossing signal. The controller is configured to monitor tissue impedance, and in response to a threshold value of impedance being reached, to cause a power level of the electrosurgical energy to transition from a first power level to a second power level. The slew rate of the power transition may be in accordance with a transition function, such as a cosine function. The power transition may additionally or alternatively be performed during, or correlated with, an electrosurgical signal zero crossing. The system also includes an electrosurgical instrument including at least one active electrode adapted to apply electrosurgical energy to tissue for treatment.

主权项

1. An electrosurgical system comprising:
an electrosurgical generator adapted to supply electrosurgical energy to tissue at a power level responsive to a generator power level signal; sensor circuitry adapted to monitor tissue impedance and output an impedance signal in response thereto, the sensor circuitry further adapted to monitor a zero crossing of the electrosurgical energy and output a zero crossing signal in response thereto; a microprocessor operably coupled to the electrosurgical generator and the sensor circuitry and adapted to receive the impedance signal and the zero crossing signal and to compare the impedance signal to an impedance transition point, and configured to output a generator power level signal, wherein the generator output signal causes the electrosurgical generator to transition from a first power level to a second power level in accordance with a transfer function defined substantially in accordance with a cosine function during a zero crossing of the electrosurgical energy; wherein the microprocessor is further adapted to increase the impedance transition point when the second power level is greater than the first power level and/or decrease the impedance transition point when the second power level is less than the first power level; and an electrosurgical instrument including at least one active electrode adapted to apply electrosurgical energy to tissue for treatment.