Abstract: An AC/DC converter includes: a rectifier circuit that rectifies an alternating current input; a PFC circuit that has an inductance element, a switching element, and a diode and steps up and outputs an output of the rectifier circuit; a DC/DC converting circuit that converts an output of the PFC circuit into a direct current voltage power source of a predetermined voltage value; a target voltage command generating circuit that designates the target voltage so that the target voltage is low in a region; a target voltage converting circuit that generates a converted target voltage by converting the target voltage designated by the target voltage command generating circuit so that the target voltage is changed in a first period; and a voltage command generating circuit that generates an on and off control signal for controlling on and off of the switching element of the PFC circuit.

Abstract: An information processing apparatus includes: a processor; a plurality of power controllers, each of the power controllers includes: an electricity supply that supplies electricity supplied from an inserted power supply cable to the processor, and a detector that detects and notifies a half-disconnected state of the power supply cable; and a current controller that in response to a notification from any of the detectors, decreases output current from the electricity supply in a power controller which falls under the half-disconnected state, and increases output current from an electricity supply in another power controller.

Abstract: A direct current to direct current converter includes: a transformer configured to vary a direct-current voltage applied to a first side and output the varied direct-current voltage to a second side; a switch configured to periodically switch the voltage applied to the first side of the transformer; a load-current detecting circuit configured to detect load current flowing in the second side of the transformer; and a switching-frequency switching circuit configured to switch, when a magnitude of the load current detected by the load-current detecting circuit is smaller than a predetermined threshold, a frequency for switching the switch from a first frequency to a second frequency lower than the first frequency, and to switch, when the magnitude of the load current detected by the load-current detecting circuit is larger than the predetermined threshold, the frequency for switching the switch from the second frequency to the first frequency.

Abstract: In a method for manufacturing a monolithic ceramic electronic component, metal thin-films to be processed into internal electrodes are formed on green ceramic sheets and include first metal particles and second metal particles that are more oxidizable than the first metal. The internal electrodes are formed in a firing step such that the second metal particles located near the interfaces between the metal thin-films and the green ceramic sheets are selectively oxidized and the second metal particles located in inner portions of the metal thin-films are deposited outside the metal thin-films and oxidized such that oxide layers including the oxidized second metal particles are formed along the interfaces and the first metal particles are sintered such that the first metal particles grow along the oxide layers.

Abstract: A manufacturing method for an electronic component includes a process of forming a lower electrode and a dummy electrode, which are electrically connected to each other, on a substrate, and a process of forming a piezoelectric thin film on the dummy electrode and the lower electrode while a predetermined bias potential is applied to the lower electrode via the dummy electrode. In this method, the piezoelectric thin film is formed on the lower electrode by stabilizing the potential of the lower electrode, thereby decreasing the surface roughness of the piezoelectric thin film. It is thus possible to manufacture an electronic component that exhibits excellent piezoelectric characteristics, in which the electromechanical coupling coefficient and the quality factor of a resonator are increased.

Abstract: A piezoelectric thin-film resonator includes a supporting substrate. A piezoelectric thin-film is formed on the supporting substrate. A lower electrode and an upper electrode are formed with the piezoelectric thin-film therebetween. The stiffness of at least one of the lower and upper electrodes is higher than that of the piezoelectric thin-film.

Abstract: A piezoelectric thin film resonator having a stabilized temperature characteristic of resonant frequency, a method for manufacturing the same, and a communication apparatus using the piezoelectric thin film resonator are provided. The piezoelectric thin film resonator is provided with a substrate having an opening, first and second insulation films which are provided on one surface of the substrate while covering the opening and which primarily include SiO2 and Al2O3, respectively, Al2O3 having oxygen defect and being in an amorphous state, and a piezoelectric thin film which is provided on the second insulation film and is sandwiched between electrodes and which primarily includes ZnO.

Abstract: A piezoelectric thin film resonator having a stabilized temperature characteristic of resonant frequency, a method for manufacturing the same, and a communication apparatus using the piezoelectric thin film resonator are provided. The piezoelectric thin film resonator is provided with a substrate having an opening, first and second insulation films which are provided on one surface of the substrate while covering the opening and which primarily include SiO2 and Al2O3, respectively, Al2O3 having oxygen defect and being in an amorphous state, and a piezoelectric thin film which is provided on the second insulation film and is sandwiched between electrodes and which primarily includes ZnO.

Abstract: A piezoelectric thin-film resonator includes a supporting substrate. A piezoelectric thin-film is formed on the supporting substrate. A lower electrode and an upper electrode are formed with the piezoelectric thin-film therebetween. The stiffness of at least one of the lower and upper electrodes is higher than that of the piezoelectric thin-film.

Abstract: A piezoelectric thin film resonator having a stabilized temperature characteristic of resonant frequency, a method for manufacturing the same, and a communication apparatus using the piezoelectric thin film resonator are provided. The piezoelectric thin film resonator is provided with a substrate having an opening, first and second insulation films which are provided on one surface of the substrate while covering the opening and which primarily include SiO2 and Al2O3, respectively, Al2O3 having oxygen defect and being in an amorphous state, and a piezoelectric thin film which is provided on the second insulation film and is sandwiched between electrodes and which primarily includes ZnO.

Abstract: A manufacturing method for an electronic component includes a process of forming a lower electrode and a dummy electrode, which are electrically connected to each other, on a substrate, and a process of forming a piezoelectric thin film on the dummy electrode and the lower electrode while a predetermined bias potential is applied to the lower electrode via the dummy electrode. In this method, the piezoelectric thin film is formed on the lower electrode by stabilizing the potential of the lower electrode, thereby decreasing the surface roughness of the piezoelectric thin film. It is thus possible to manufacture an electronic component that exhibits excellent piezoelectric characteristics, in which the electromechanical coupling coefficient and the quality factor of a resonator are increased.

Abstract: A piezoelectric thin-film resonator includes a supporting substrate. A piezoelectric thin-film is formed on the supporting substrate. A lower electrode and an upper electrode are formed with the piezoelectric thin-film therebetween. The stiffness of at least one of the lower and upper electrodes is higher than that of the piezoelectric thin-film.

Abstract: A piezoelectric resonator includes a substrate and a vibrator. The vibrator includes a thin-film portion having at least one piezoelectric thin-film layer disposed on the substrate and at least one pair of upper and lower electrodes disposed on the substrate. The vibrator has a structure in which the thin-film portion is sandwiched from the upper and lower surfaces thereof by the upper and lower electrodes, which oppose each other in the depth direction, and the overlapping portion of the vibrator defined by the opposing upper and lower electrodes has a tetragonal shape, when viewed in the depth direction, other than a rectangle and a square, the tetragonal shape having substantially parallel sides having a longitudinal length equal to or smaller than about 10 times the oscillatory wavelength and also having at least one portion in which the distance between opposing electrode edges varies.

Abstract: A piezoelectric thin film resonator having a stabilized temperature characteristic of resonant frequency, a method for manufacturing the same, and a communication apparatus using the piezoelectric thin film resonator are provided. The piezoelectric thin film resonator is provided with a substrate having an opening, first and second insulation films which are provided on one surface of the substrate while covering the opening and which primarily include SiO2 and Al2O3, respectively, Al2O3 having oxygen defect and being in an amorphous state, and a piezoelectric thin film which is provided on the second insulation film and is sandwiched between electrodes and which primarily includes ZnO.

Abstract: A piezoelectric resonator includes a substrate, a vibration unit disposed on the substrate and having a structure in which at least one pair of an upper electrode and a lower electrode opposed to each other, the upper and lower electrodes sandwiching the upper and lower surfaces of an internal thin-film portion including at least one layer of a piezoelectric thin-film, and an external thin-film portion provided under the lower electrode and including at least one layer of a piezoelectric thin-film or a dielectric thin-film, the vibration unit being vibrated in an n-th harmonic (n is an integer of 2 or more), the upper electrode and the lower electrode being provided substantially in the positions of the loops of the n-th harmonic.

Abstract: A piezoelectric resonator includes a substrate, a vibration unit disposed on the substrate and having a structure in which at least one pair of an upper electrode and a lower electrode opposed to each other, the upper and lower electrodes sandwiching the upper and lower surfaces of an internal thin-film portion including at least one layer of a piezoelectric thin-film, and an external thin-film portion provided under the lower electrode and including at least one layer of a piezoelectric thin-film or a dielectric thin-film, the vibration unit being vibrated in an n-th harmonic (n is an integer of 2 or more), the upper electrode and the lower electrode being provided substantially in the positions of the loops of the n-th harmonic.

Abstract: A piezoelectric thin-film resonator includes a supporting substrate. A piezoelectric thin-film is formed on the supporting substrate. A lower electrode and an upper electrode are formed with the piezoelectric thin-film therebetween. The stiffness of at least one of the lower and upper electrodes is higher than that of the piezoelectric thin-film.

Abstract: A piezoelectric thin film resonator having a stabilized temperature characteristic of resonant frequency, a method for manufacturing the same, and a communication apparatus using the piezoelectric thin film resonator are provided. The piezoelectric thin film resonator is provided with a substrate having an opening, first and second insulation films which are provided on one surface of the substrate while covering the opening and which primarily include SiO2 and Al2O3, respectively, Al2O3 having oxygen defect and being in an amorphous state, and a piezoelectric thin film which is provided on the second insulation film and is sandwiched between electrodes and which primarily includes ZnO.

Abstract: A manufacturing method for an electronic component includes a process of forming a lower electrode and a dummy electrode, which are electrically connected to each other, on a substrate, and a process of forming a piezoelectric thin film on the dummy electrode and the lower electrode while a predetermined bias potential is applied to the lower electrode via the dummy electrode. In this method, the piezoelectric thin film is formed on the lower electrode by stabilizing the potential of the lower electrode, thereby decreasing the surface roughness of the piezoelectric thin film. It is thus possible to manufacture an electric component that exhibits excellent piezoelectric characteristics, in which the electromechanical coupling coefficient and the quality of a resonator are increased.

Abstract: A piezoelectric resonator includes a substrate and a vibrator. The vibrator includes a thin-film portion having at least one piezoelectric thin-film layer disposed on the substrate and at least one pair of upper and lower electrodes disposed on the substrate. The vibrator has a structure in which the thin-film portion is sandwiched from the upper and lower surfaces thereof by the upper and lower electrodes, which oppose each other in the depth direction, and the overlapping portion of the vibrator defined by the opposing upper and lower electrodes has a tetragonal shape, when viewed in the depth direction, other than a rectangle and a square, the tetragonal shape having substantially parallel sides having a longitudinal length equal to or smaller than about 10 times the oscillatory wavelength and also having at least one portion in which the distance between opposing electrode edges varies.