Motorola Corporation

Brian M Mancini

Thomas A Knecht

Jin Huang

Pallab Midya

Jean-Robert Achille

Joseph P Krause

David J Sieben

A transformer circuit (10) for a piezoelectric transformer (12) having dual inputs which can piezoelectrically interfere with one another to provide adjustable output gain. The transformer circuit (10) provides two pulse-position-modulated input signals (18, 20) which are substantially identical waveforms, but being phase shifted from one another. When the signals (18, 20) constructively interfere maximum gain is achieved. When the two signals (18, 20) destructively interfere minimum gain is achieved. The waveforms may be of any arbitrary type including square, sine, triangle, sawtooth or irregular. Both input signals (18, 20) are at a resonant frequency of the piezoelectric transformer (12) and have a fifty percent duty cycle so as to always provide highest efficiency within the transformer (12). In addition, when the two input signals (18, 20) destructively interfere with each other piezoelectrically, the input impedance of the transformer (12) rises so as to lessen power dissipation within the transformer (12) which subsequently reduces adverse heating effects.

Driving circuit for multisectional piezoelectric transformers using

A piezoelectric transformer (10) operating in a thickness-shear vibration mode (26). The piezoelectric transformer (10) comprises a lithium niobate substrate (12) having first and second acoustically coupled portions (16,22), and a plurality of substantially opposing pairs of primary and secondary electrodes (14,20) disposed thereon. An input AC voltage applied to the primary electrode pairs (14) exciting a thickness-shear vibration (26) which couples to the secondary electrode pairs (20) producing an output AC voltage therebetween. The primary and secondary electrodes (14,20) being electrically connected in various combinations of parallel and series connections to provide a desired step-up or step-down voltage transfer ratio.

Lithium niobate piezoelectric transformer operating in thickness-shear

A multi-pole monolithic crystal filter (100) having at least three asymmetrically acoustically coupled resonators (104) on a piezoelectric blank (102) to provide an improved phase response (302). The resonators (104) are positioned substantially in inverse proportion to predetermined ladder network coupling coefficients to achieve an improved phase response filter. The ladder network coupling coefficients are selected from designs including Bessel, Gaussian, linear phase and equiripple models. In this way, a predetermined improved phase response (302) is obtained monolithically without discrete interstage tuning components.

Apparatus and method for an asymmetrical multi-pole monolithic crystal

A shielding apparatus for use with a non-conductive package has an insulated lid (102) which is retained in contact with a substrate (104) for holding an electrical circuit. The shielding apparatus includes a first conductive flash (201) deposited on the interior surface of the insulated lid (102), to produce a substantially contiguous conduction layer, and a second conductive flash (203) deposited over a film (110) disposed on the edge of the insulated lid (102), to produce a partially contiguous conduction layer. The shielding apparatus also includes a layer (108) for affixing the insulated lid (102) to the substrate (104), to produce an enclosure for isolating the electrical circuit from extraneous radio frequency (RF) energy.

Shielding apparatus for non-conductive electronic circuit packages

In-situ adjustments to frequency characteristics of an electronic device such as a piezoelectric element (40) can be accomplished by means of a predetermined atmosphere (18) enclosed within a package comprised of a base (12) and a cover (14) and an included amount of sputterable electrode material (22). By attachment of appropriate electric potentials (2), electrode molecules can be sputtered onto the electrode surfaces adjusting the resonant frequency characteristics of a crystal filter.

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Carol Stream, IL, United States of America

Brian M Mancini