Ultrasonic power supply
US4973876A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 20, 1989 |
| Grant date | Nov 27, 1990 |
| Priority date | — |
| Expiry date | Sep 20, 2009 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C66/939
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An ultrasonic power supply for driving a piezoelectric transducer at its parallel resonant frequency includes a clamped-mode resonant converter for converting direct current to alternating current and a demodulator, a loop filter and a voltage controlled oscillator in a phase locked loop configuration. The power supply also includes a control circuit for adjustably setting and controlling the amplitude of vibration of the transducer, and providing during start-up a ramp start. The power supply, further, includes a control circuit for limiting the maximum permissible current flow to the transducer and the reverse current flow from the transducer resulting from stored mechanical energy. Both control circuits provide feedback signals which control the pulse width modulated operation of the clamped-mode resonant converter and thereby control the voltage amplitude of the alternating current output from the converter. The phase locked loop circuit causes the frequency of the alternating current output from the converter to track the parallel resonant frequency of the transducer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.