In accordance with various embodiments, methods for controlling electrical power provided to tissue via a surgical device may comprise providing a drive signal to a surgical device; receiving an indication of an impedance of the tissue; calculating a rate of increase of the impedance of the tissue; and...http://www.google.com.hk/patents/US20110087214?utm_source=gb-gplus-share專利 US20110087214 - SURGICAL GENERATOR FOR ULTRASONIC AND ELECTROSURGICAL DEVICES
