Embodiments described herein include a resonant process monitor and methods of forming such a resonant process monitor. In an embodiment, the resonant process monitor includes a frame that has a first opening and a second opening. In an embodiment, a resonant body seals the first opening of the frame. In an embodiment, a first electrode on a first surface of the resonant body contacts the frame and a second electrode is on a second surface of the resonant body. Embodiments also include a back plate that seals the second opening of the frame. In an embodiment the back plate is mechanically coupled to the frame, and the resonant body, the back plate, and interior surfaces of the frame define a cavity.

A method and apparatus for converting power comprising an input bridge having an input adapted for coupling to a DC source, a piezoelectric transformer having an input coupled to an output of the input bridge, and an output bridge having an input coupled to an output of the piezoelectric transformer and an output adapted to couple to a load. A trajectory controller, coupled to the input bridge and output bridge, (1) measures current and voltage in the input bridge, the output bridge or both, (2) measures a current into or out of the piezoelectric transformer, (3) determines switch timing for control signals for the input bridge and output bridge based upon the measured current and/or voltage, and (4) applies the control signals to the input bridge and output bridge.

A piezoelectric transformer comprises at least a laminate of a first member, a first piezoelectric element, a second piezoelectric element and a second member sequentially stacked one on the other in the above-listed order and a pressurizing mechanism for squeezing the first member and the second member together in the stacking direction. The ratio of the electromechanical coupling coefficient k.sub.33 relative to the electromechanical coupling coefficient k.sub.31 (k.sub.33/k.sub.31) of the first piezoelectric element and the second piezoelectric element is not less than 2.0.

The electrical energy conversion system comprises: a converter including E first switching assembly or assemblies, each associated with an input voltage and including two first switches; N second switching assembly or assemblies, each associated with an output voltage and including two second switches; and at least one piezoelectric assembly connected to a switch; E>1, N>1; a control device configured for controlling, during a resonance cycle, a switching of the switches so as to alternate phases at constant voltage and phases at constant load across said piezoelectric assembly or assemblies.

The converter comprising an electrical transformer having a primary winding connected to a first switching assembly and a secondary winding connected to a second switching assembly, and each piezoelectric assembly being connected between a switch and a winding.

A wireless power transmitter includes: a switching unit configured to receive a direct current (DC) voltage and to perform switching to output a first alternating current (AC) voltage; a piezoelectric transformer configured to receive the first AC voltage through a first piezoelectric element, and to output a second AC voltage corresponding to mechanical vibration of a second piezoelectric element caused by mechanical vibration of the first piezoelectric element; and a resonator configured to receive the second AC voltage to wirelessly transmit power.

A converter of an input voltage into at least one output voltage, including a pair of first and second piezoelectric assemblies; a first bridge including two first switching branches each having at least one first switch; a second bridge including two second switching branches each having at least one second switch; each piezoelectric assembly including a first end connected to the first bridge and a second end connected to the second bridge; each first switch being connected between a terminal of the input voltage and a first end; each second switch being connected between a terminal of the output voltage and a second end. It includes at least one complementary switch connected directly between the ends of a pair of piezoelectric assemblies, connected to a same bridge,

A control circuit and a method for controlling a piezoelectric transformer are disclosed. In an embodiment the control circuit includes an inductor and a control unit, wherein the control circuit is configured to apply a voltage with a periodic waveform to a piezoelectric transformer, wherein a period duration of the voltage is specified by a control frequency and adjust the control frequency of the applied voltage as a function of an average current intensity of a current flowing through the inductor.

The present disclosure relates to circuitry for driving a piezoelectric transducer. The circuitry may be implemented as an integrated circuit and comprises driver circuitry configured to supply a drive signal to the piezoelectric transducer to cause the transducer to generate an output signal and active inductor circuitry configured to be coupled with the piezoelectric transducer. The active inductor circuitry may be tuneable to adjust a frequency characteristic of the output signal.

A printed circuit board comprises a first mounting surface, a second mounting surface, and a piezoelectric transformer. The piezoelectric transformer has a piezoelectric substance, external electrodes, and a frame substrate. The second mounting surface has a projection region. There is a first region from a first location, where an end portion further from the output electrode out of end portions of the input electrode is projected onto the second mounting surface in the projection region, to a second location, where an end portion closer to the output electrode out of the end portions of the input electrode is projected onto the second mounting surface, the first region being a mounting allowed region where an electronic component is mounted.

The invention relates to a piezoelectric transformer having a piezoelectric element (1) of the length L, wherein an input voltage U.sub.in can be applied on an input side (2) for being transformed into an output voltage U.sub.out on the output side (3) according to a transformation ratio U.sub.out/U.sub.in=K.sub.u. The piezoelectric element (1) comprises multiple plies (4a, 4b, 4c) of inner electrodes, which are arranged in multiple different layers (S1, S2, S3). Each ply (4a, 4b, 4c) of inner electrodes extends along at least one predetermined sub-section of a predetermined length, wherein sub-sections of plies (4a, 4c) of a first group of layers (S1, S3) and sub-sections of plies (4b) of a second group of layers (S2) have different dimensions, so that the piezoelectric transformer satisfies the following condition: C.sub.in≤N.sup.2C.sub.out, wherein C.sub.in indicates the input capacitance, C.sub.out indicates the output capacitance, and N indicates the transformation ratio of the ideal transformer.