Multiple frequency unambiguous phase detector for phacoemulsification system

Abstract

A method for determining the voltage current phase relationship of a piezoelectric phacoemulsification handpiece includes the steps of obtaining an AC voltage signal corresponding to the operating AC voltage of a piezoelectric handpiece and obtaining an AC current signal corresponding to the operating AC current of the piezoelectric handpiece. From said AC current signal, onset of a current cycle is determined and after onset of the current cycle, a voltage (V.sub.I) corresponding to a time necessary for the AC current signal to reach a maximum value is produced. Also, after onset of the current cycles, a voltage (V.sub.v) corresponding to a time necessary for the AC voltage signal to reach a maximum value is produced. Using an A/D converter, a digital output (D.sub.v) corresponding to (V.sub.v) is produced and a digital output (D.sub.I) corresponding to (V.sub.I) is produced. Comparing (D.sub.v) and (D.sub.I) determines the phase relationship between the voltage and current of the piezoelectric phacoemulsification handpiece.

Dependencies are inferred from the claim text.