Patent ID: 8546996
Filing Date: 2013-10-01
Classification: A61B,A61N,B06B,G05B

Abstract:
1. A method of driving an ultrasonic transducer of a surgical instrument, the method comprising: generating by a generator coupled to an ultrasonic transducer at least one time varying electrical signal at a resonant frequency of the ultrasonic transducer; sampling the frequency of the at least one time varying electrical signal over a predetermined time period to obtain at least two sampled frequency data points of the at least one time varying signal; calculating a frequency slope between the at least two sampled frequency data points of the at least one time varying electrical signal over the predetermined time period, where the frequency slope is the difference between the at least two sampled frequency data points over the predetermined time period; comparing the frequency slope to a frequency slope threshold; and triggering a first response of the generator when the frequency slope crosses the frequency slope threshold.