Fujitsu Corporation

Fujitsu Media Devices Limited

Kabushiki Kaisha Toshiba

Taiyo Yuden Mobile Technology Co., Ltd.

Fujimaru Industry Co., Ltd.

Naoyuki Mishima

Yu Yonezawa

Satoshi Ueda

Tadashi Nakatani

Anh Tuan Nguyen

Shingo Masuko

Michio Miura

Noboru Wakatsuki

Xiaoyu Mi

Takeaki Shimanouchi

Masao Irikura

Masanori Ueda

Nobuhisa Aoki

Yuuta Nakaya

Takeshi Takano

Masahiko Imai

Seiichi Mitobe

Youichi Masuda

Shunichi Aikawa

Yasuo Ebata

Takumi Kooriike

Satoshi Ichikawa

Hirohisa Tanaka

Toru Uemura

Kunihisa Wada

Takamasa Oto

Hideaki Deguchi

Motoyoshi Takase

A switching power supply includes: a first switch provided between a positive terminal of a DC power supply and a positive terminal of a load; a second switch connected in parallel with the first switch; a first capacitor provided between the second switch and a node of the first switch on a DC power supply side; a first inductor provided between the first capacitor and the positive terminal of the DC power supply; and a control circuit that turns off the second switch after the first switch is turned off and when or before a voltage across the first capacitor becomes zero.

Switching power supply, control circuit for controlling switching power supply, control method of switching power supply and module substrate

The present invention is a switch circuit equipped with a first switch connected between another end of an inductive load having a one end connected to a one end of a DC power supply and another end of the DC power supply, a capacitor connected between the another end of the inductive load and the another end of the DC power supply and connected in parallel with the first switch, a second switch that connects the another end of the inductive load and the capacitor, a third switch that connects a one end of the capacitor on an inductive load side to the one end of the inductive load so as to be parallel to the second switch, and a control circuit that turns ON the second switch before the first switch is turned OFF and turns OFF the second switch before the first switch is turned ON after being turned OFF.

Switch circuit with inductive load and capacitor

The present invention is a DC-DC converter characterized by including a switch element that is provided between one end of a DC power source and one end of a load and turns ON and OFF current input from the DC power source, an inductance element that is provided between one end of the switch element on a load-side end and includes a doughnut-shaped magnetic core and a conductive wire wound around the magnetic core, a commutation switch provided between a node between the switch element and the inductance element and a ground potential, and a capacitance element provided between a node between the inductance element and the load and the ground potential, wherein a magnetic flux density of the magnetic core varies partially.

DC-DC converter

A micro-switching device includes a base substrate, a fixing member on the substrate, a movable part having an end fixed to the fixing member and extending along the substrate, a movable contact electrode provided on the movable part and facing away from the substrate, a pair of stationary contact electrodes bonded to the fixing member and including a region facing the movable contact electrode, a movable driver electrode between the movable contact electrode and the stationary end on the movable part at a surface facing away from the substrate, and a stationary driver electrode bonded to the fixing member and including an elevated portion having a region facing the movable driver electrode. The elevated portion is provided with steps facing the movable driver electrode, where the steps are closer to the substrate as they are farther from the movable contact electrode.

Micro-switching device and manufacturing method for the same

A drive control method for a micro machine device is provided. The micro machine device is made up of first and second electrodes opposed to each other and a dielectric layer disposed between them. The drive control method includes the steps of applying a control voltage between the first and the second electrodes so that an electrostatic force is exerted on the first and the second electrodes for displacing the first or the second electrode, and switching polarity of the control voltage at a predetermined period or a shorter period.

Drive control method and unit for micro machine device

In a method for drive controlling a micro machine device including two electrodes opposing each other and a dielectric layer sandwiched therebetween, a control voltage in a rectangular waveform in which positive and negative polarities are alternately inverted is applied between the two electrodes. A current passing through the micro machine device due to the application of the control voltage are detected with respect to positive and negative sides, and parameters related to a capacitance of the micro machine device are acquired with respect to the positive and negative sides on the basis of the detected current. The control voltage is controlled so that the parameters acquired with respect to the positive and negative sides accord with each other. Thus, variation of the capacitance between the positive side and the negative side can be suppressed in switching drive of a variable capacitance device.

Apparatus and method for drive controlling micro machine device

A switching power supply includes: a first switch provided between one end of a DC power supply and one end of a load; a second switch provided between a node of the first switch located on a load side and another end of the DC power supply; a capacitor provided between the second switch and the another end of the DC power supply; a third switch provided between a node of the first switch located on a DC power supply side and a node between the second switch and the capacitor; and a delay circuit that is provided between the third switch and the node between the second switch and the capacitor and delays a current for charging the capacitor, wherein the second switch is turned on in a period during which the first switch is kept on.

Switching power supply, control circuit controlling switching power supply and control method of switching power supply

A switch includes a movable portion, a first electrode and a second electrode. The movable portion is provided on a substrate and moves with respect to the substrate. The first electrode is provided on the movable portion. The second electrode is able to contact with the first electrode and is fixed to the substrate. f&#xd7;Ro&#xd7;C&#x2266;1.6&#xd7;10when an operation frequency is represented as 'f' (Hz), a transmission impedance is represented as 'Ro' (&#x3a9;), and a capacitance in &#x201c;OFF&#x201d; state between the first electrode and the second electrode is represented as &#x201c;C&#x201d; (F).

Switch with movable portion

A micro-switching device includes a movable electrode provided on a movable support having an end fixed to a fixing member. The switching device also includes first and second stationary electrodes. The movable electrode includes first and second contact portions. The first stationary electrode includes a third contact portion facing the first contact portion of the movable electrode. The second stationary electrode includes a fourth contact portion facing the second contact portion of the movable electrode. The distance between the first and the third contact portions is smaller than the distance between the second and the fourth contact portions. The switching device further includes a driving mechanism having a driving force generation region provided on the movable support. The center of gravity of the driving force generation region is closer to the second contact portion than to the first contact portion.

Micro-switching device

A micro-switching device includes a fixing portion, a movable portion, a first electrode with first and second contacts, a second electrode with a third contact contacting the first contact, and a third electrode with a fourth contact opposing the second contact. In manufacturing the micro-switching device., the first electrode is formed on a substrate, and a sacrifice layer is formed on the substrate to cover the first electrode. Then, a first recess and a shallower second recess are formed in the sacrifice layer at a position corresponding to the first electrode. The second electrode is formed to have a portion opposing the first electrode via the sacrifice layer, and to fill the first recess. The third electrode is formed to have a portion opposing the first electrode via the sacrifice layer; and to fill the second recess. Thereafter the sacrifice layer is removed.

Micro-switching device and method of manufacturing the same

A surface acoustic wave device includes a package having a cavity, a SAW chip housed in the cavity, a resin sealing the cavity, and a metal thin film provided on the resin.

Surface acoustic wave device, package for the device, and method of fabricating the device

A switch includes a first member, one end of which being secured to a substrate, multiple first beam portions respectively having multiple first contact portions, one ends of the multiple beam portions being secured to the first member, multiple contact switch portions connected in parallel, the multiple first contact portions and multiple second contact portions being in a contact state or in a non-contact state in the multiple contact switch portions, and resistors arranged respectively between the multiple contact switch portions and a common connection point to which the multiple contact switch portions are coupled. When at least one of the multiple switch portions is in a contact state, one of the resistors corresponding to the at least one of the multiple switch portions in a contact state has a resistance value greater than another one of the resistors corresponding to at least one of the multiple contact switch portions that is in a non-contact state.

Switch

A surface acoustic wave device has a SAW device elementand a packagehousing the SAW device element. The package includes a resin substratehaving metal patternsandformed on both surfaces thereof, and a resin cap. The SAW device element is mounted on one of the metal patterns of the resin substrate. The resin cap is adhered to the resin substrate to cover the SAW device element. The surfaces of the resin substrate are flush with corresponding end surfaces of the resin cap.

Surface acoustic wave device and manufacturing method of the same

An elastic boundary wave device includes a first piezoelectric substrate, IDTs arranged thereon, a first dielectric film having a smoothed surface that covers the IDTs, a second substrate that is a silicon-based substrate, and a second dielectric film provided on a main surface of the second substrate. The smoothed surface of the first dielectric surface and a surface of the second dielectric film are joined together.

Elastic boundary wave device and method of manufacturing the same

A surface acoustic wave device includes a surface acoustic wave chip having a piezoelectric substrate on which comb-like electrodes and electrode pads are formed, a package housing the surface acoustic wave chip, and electrode patterns provided on a bottom surface of the package. The bottom surface of the package is wider than a top surface of the package. The electrode patterns are away from edges of the bottom surface of the package.

Growing community of inventors

Yokohama, Japan

Naoyuki Mishima