Apparatus and method for controlling excitation frequency of magnetostrictive transducer
US7715167B2 · kind B2 · utility
Inventors
Key dates
| Filing date | Feb 13, 2006 |
| Grant date | May 11, 2010 |
| Priority date | — |
| Expiry date | Mar 13, 2029 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61C17/20
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
Apparatus and method for controlling the frequency of the current in the excitation coil of the handpiece of a dental magnetostrictive ultrasonic scaling unit, or similar transducer. A microprocessor continually samples a predetermined function of the current through the excitation coil, and adjusts the frequency for a function maximum, performing coarse and fine frequency adjustments. The function can be proportional to the current, its time-derivative, or combination thereof. A voltage-controlled oscillator is employed, controlled by pulse-width modulation from the microprocessor. The base frequency scan is performed each time the handpiece is energized by the practitioner, assuring automatic optimal frequency adjustment at all times and under all conditions. Apparatus according to the invention does not require transformers, sensing coils, or complex power- or impedance-sensing circuitry, and covers a wide range of resonant frequencies for different insert types. A configuration with multiple handpieces is supported.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.