An electrosurgical generator configured to output radio frequency (RF) energy having a current-source type behavior is provided. The generator has a buck converter having a voltage source, at least one switch and an inductor. The generator also has an RF stage configured to output the RF energy. A sensor circuit configured to measure at least one parameter of the RF energy and a controller configured to receive the measured parameter from the sensor circuit and control the output of the electrosurgical generator based on the measured parameter may also be provided in the electrosurgical generator.
