The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 04, 1990
Filed:
Apr. 06, 1987
Ying-Ching Lo, Fremont, CA (US);
Samuel Zambre, Palo Alto, CA (US);
Tolentino Escorcio, San Leandro, CA (US);
Alcon Laboratories, Fort Worth, TX (US);
Abstract
A driver system for an ultrasonic probe using a tunable inductor in series with the piezoelectric crystal excitation transducer in the probe. The bias current through this flux moduation coil is controlled by the system such that the inductance of the tunable inductor cancels out the capacitive reactance of the load impedance presented by the probe when the probe is being driven by a driving signal which matches the mechanical resonance frequency of the probe. The resulting overall load impedance is substantially purely resistive. The system also adjusts the frequency of the driving signal to track changing mechanical resonance conditions for the probe at different power levels. This method of operation insures substantially maximum power transfer efficiency and substantially linear power control over a range of power dissipation levels. The system determines the mechanical resonance frequency by sweeping the drive frequency and monitoring the drive current to determine the frequency at which the drive current is a maximum.