Motorola Corporation

John Mattson

Charles L Zimnicki

Jin Huang

Bruce Vojak

Jiashi Yang

A power transformer circuit (100) includes a capacitor (120) and a resonator (140). The resonator (140) is coupled in series with the capacitor (120) and is operable to provide a substantially inductive impedance between its terminals (142,144). Resonator (140) is preferably implemented as a piezoelectric lithium niobate resonator that is operated in a thickness-shear mode. In a preferred embodiment, power transformer circuit (100) is employed as a series resonant output circuit in an electronic ballast (500) for powering at least one gas discharge lamp (30).

Power transformer circuit with resonator

A high frequency acoustic wave piezoelectric device (10) having parallel etched channels cut into a surface of a piezoelectric substrate so as to form micromachined ridges (20). Top electrodes (30) are located on tops (26) of the ridges (20) and bottom electrodes (32) are located on bottoms of the channels in spacings (22) between ridges (20). The top and bottom electrodes (30, 32) are offset from each other and substantially non-opposing. The electrodes (30, 32) generate a sufficient vertical electrical field (38) when driven to cause the ridges (20) to resonate. A height (28) of the ridges (20) define the operating frequency. The ridges (20) can be made small enough to produce frequencies well over 100 MHz in a fundamental bulk acoustic wave mode.

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Palatine, IL, United States of America

John Mattson