Multiple frequency unambiguous phase detector for phacoemulsification system
US5852794A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 22, 1997 |
| Grant date | Dec 22, 1998 |
| Priority date | — |
| Expiry date | Jan 22, 2017 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB06B2201/76
- WIPO fieldMedical technology
- WIPO sectorInstruments
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.