HIGH-FREQUENCY GENERATOR FOR PERFORMING HIGH-FREQUENCY SURGERY HAVING ADJUSTABLE POWER LIMITATION, AND METHOD FOR CONTROLLING THE POWER LIMITATION

摘要

The invention relates to an HF generator and to a method for limiting the output effective power of the HF generator, especially for performing HF surgical cutting and coagulation of human or animal tissue. According to the invention, the output voltage and the HF output current of the HF generator (1) are detected by at least two detector devices (2, 3), the peak values and the effective values of the HF output voltage and of the output current as well as the mean value of the output effective power of the HF generator are determined by an evaluation device (4), and the calculated mean value is compared to a defined maximum mean value of the output effective power of the HF generator by a comparison device (5). Afterwards, a modulation device (7) modulates the HF output voltage using a pulse-shaped modulation signal. A control device (6) controls the modulation device (7) in such a manner that the pulse duration of the pulse-shaped modulation signal and/or the pulse duration between the pulse-shaped modulation signals is modified in order to keep the peak value of the output voltage constant when the calculated mean value of the output effective power is greater than the maximum mean value of the output effective power. Alternatively, the HF generator (1) is equipped with a sensor for evaluating the intensity of electric arcs between an electrode connected to the HF generator and the tissue.