Patents by Inventor Yu Yonezawa
Yu Yonezawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20120182769Abstract: A DC-DC converter is disclosed that includes a first winding of a first transformer to which direct current power is supplied, a switching element configured to be connected in series with the first winding of the first transformer, a first winding of a second transformer and a capacitor configured to be connected in series with each other and in parallel with the switching element, a second winding of the first transformer configured to be coupled with the first winding of the first transformer, output terminals configured to be connected to the second winding of the first transformer and to output direct current power, and a pair of second windings of the second transformer configured to be coupled with the first winding of the second transformer, the second windings of the second transformer being connected in parallel with each other with reverse polarity between the output terminals.Type: ApplicationFiled: November 29, 2011Publication date: July 19, 2012Applicant: FUJITSU LIMITEDInventors: Yu Yonezawa, Yoshiyasu Nakashima
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Publication number: 20120163052Abstract: A power supply unit includes multiple input terminals to which alternating-current power is input; a positive terminal and a negative terminal for outputting direct-current power; a rectifier circuit configured to rectify the input alternating-current power; a first inductor connected to the rectifier circuit; a first capacitor connected between the positive terminal and the negative terminal; a first rectifying device connected between the output terminal of the first inductor and the positive terminal and having a rectification direction in a direction from the output terminal of the first inductor toward the positive terminal; a switching device connected between an input terminal of the first rectifying device and the negative terminal; a second rectifying device and a second capacitor connected in parallel to the switching device; and a second inductor connected between a connection of the second rectifying device and the second capacitor and the positive terminal.Type: ApplicationFiled: September 21, 2011Publication date: June 28, 2012Applicant: FUJITSU LIMITEDInventors: Yu Yonezawa, Yoshiyasu Nakashima
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Publication number: 20120153929Abstract: A controller CT1 switches on a first switch SW1, and the direct-current voltage given from a power source BAT flowing through a first inductor L1 is smoothed by a capacitor C1 and is output from an output terminal OUT1. After a specified period of time has elapsed since the first switch SW1 was turned off by the controller CT1, the second switch SW2 and the third switch SW3 are turned on approximately at the same time. The electric current which was flowing through the first inductor L1 is branched into the second switch SW2 and the third switch SW3, and the electric current flowing through the parasitic diode Dp1 of the second switch SW2 is reduced. As a result, when the second switch SW2 is turned off, the recovery current flowing through the parasitic diode Dp1 is reduced.Type: ApplicationFiled: December 27, 2011Publication date: June 21, 2012Applicant: Fujitsu LimitedInventors: Yu YONEZAWA, Hideaki Deguchi, Yoshiyasu Nakashima
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Publication number: 20120008351Abstract: A circuit include: a first power factor correction circuit that forces current produced by the positive AC voltage to be in phase with the positive AC voltage so that a power factor of electric power is improved; a second power factor correction circuit that forces current produced by the negative AC voltage to be in phase with the negative AC voltage so that a power factor of electric power is improved; and an output circuit including a first capacitor storing first electric power with a power factor improved by the first power factor correction circuit and a second capacitor storing second electric power with a power factor improved by the second power factor correction circuit, the first capacitor and the second capacitor being provided in series, the output circuit outputting the first electric power stored in the first capacitor and the second electric power stored in the second capacitor.Type: ApplicationFiled: July 1, 2011Publication date: January 12, 2012Applicant: FUJITSU LIMITEDInventors: Yu YONEZAWA, Yoshiyasu NAKASHIMA
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Publication number: 20110215788Abstract: 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.Type: ApplicationFiled: February 23, 2011Publication date: September 8, 2011Inventors: Yu Yonezawa, Naoyuki Mishima
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Patent number: 7986507Abstract: A variable capacitor is provided which is appropriate for suppressing fluctuation in driving voltage characteristic and for achieving a larger variation ratio of static capacitance. The variable capacitor includes a fixed electrode and a movable electrode. The fixed electrode includes a first opposing face, while the movable electrode includes a second opposing face that faces the first opposing face. The movable electrode further includes a curved portion that protrudes toward the fixed electrode. The variable capacitor also includes a dielectric pattern provided on the first opposing face.Type: GrantFiled: January 24, 2008Date of Patent: July 26, 2011Assignee: Fujitsu LimitedInventors: Takeaki Shimanouchi, Masahiko Imai, Yu Yonezawa, Xiaoyu Mi, Satoshi Ueda
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Patent number: 7965159Abstract: 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.Type: GrantFiled: December 5, 2007Date of Patent: June 21, 2011Assignee: Fujitsu LimitedInventors: Tadashi Nakatani, Anh Tuan Nguyen, Satoshi Ueda, Yu Yonezawa, Naoyuki Mishima
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Patent number: 7961448Abstract: 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.Type: GrantFiled: January 23, 2008Date of Patent: June 14, 2011Assignee: Fujitsu LimitedInventors: Naoyuki Mishima, Yu Yonezawa, Takeaki Shimanouchi, Xiaoyu Mi, Takeshi Takano, Nobuhisa Aoki, Yuuta Nakaya
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Publication number: 20110057519Abstract: 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.Type: ApplicationFiled: November 16, 2010Publication date: March 10, 2011Applicant: TAIYO YUDEN Mobile Technology Co., LtdInventors: Noboru Wakatsuki, Hideaki Deguchi, Yu Yonezawa, Naoyuki Mishima
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Patent number: 7903386Abstract: 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.Type: GrantFiled: February 28, 2008Date of Patent: March 8, 2011Assignee: Fujitsu LimitedInventors: Yu Yonezawa, Takeaki Shimanouchi, Naoyuki Mishima, Satoshi Ueda, Xiaoyu Mi, Masahiko Imai
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Patent number: 7880450Abstract: 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.Type: GrantFiled: May 11, 2010Date of Patent: February 1, 2011Assignee: Taiyo Yuden Mobile Technology Co., Ltd.Inventors: Yu Yonezawa, Naoyuki Mishima
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Publication number: 20100219801Abstract: 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.Type: ApplicationFiled: May 11, 2010Publication date: September 2, 2010Applicant: FUJITSU MEDIA DEVICES LIMITEDInventors: Yu Yonezawa, Naoyuki Mishima
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Publication number: 20100220416Abstract: 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.Type: ApplicationFiled: May 3, 2010Publication date: September 2, 2010Applicant: FUJITSU MEDIA DEVICES LIMITEDInventors: Yu YONEZAWA, Naoyuki Mishima
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Patent number: 7786830Abstract: 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×Ro×C?1.6×10?4 when an operation frequency is represented as “f” (Hz), a transmission impedance is represented as “Ro” (?), and a capacitance in “OFF” state between the first electrode and the second electrode is represented as “C” (F).Type: GrantFiled: July 23, 2007Date of Patent: August 31, 2010Assignee: Fujitsu LimitedInventors: Noboru Wakatsuki, Yu Yonezawa, Naoyuki Mishima, Tadashi Nakatani, Anh Tuan Nguyen
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Patent number: 7755459Abstract: 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.Type: GrantFiled: January 14, 2008Date of Patent: July 13, 2010Assignee: Fujitsu LimitedInventors: Anh Tuan Nguyen, Tadashi Nakatani, Satoshi Ueda, Yu Yonezawa, Naoyuki Mishima
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Patent number: 7755460Abstract: 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.Type: GrantFiled: December 5, 2007Date of Patent: July 13, 2010Assignee: Fujitsu LimitedInventors: Anh Tuan Nguyen, Tadashi Nakatani, Satoshi Ueda, Yu Yonezawa, Naoyuki Mishima
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Patent number: 7486488Abstract: A load is connected with a power supply. An energizing electric contact and a transient current contact are connected electrically in parallel with each other and can do time-coordinated making and breaking operation. A capacitor is connected in series with the transient current contact. During breaking operation of the energizing contact and keeping making state of the transient current contact, a transient current from the power supply flows into the capacitor and delay voltage increase of the energizing contact using voltage drop at an internal resistance of the power supply and the load.Type: GrantFiled: September 16, 2004Date of Patent: February 3, 2009Inventors: Noboru Wakatsuki, Yu Yonezawa
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Publication number: 20080239611Abstract: 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.Type: ApplicationFiled: February 28, 2008Publication date: October 2, 2008Applicant: FUJITSU LIMITEDInventors: Yu Yonezawa, Takeaki Shimanouchi, Naoyuki Mishima, Satoshi Ueda, Xiaoyu Mi, Masahiko Imai
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Publication number: 20080210531Abstract: 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.Type: ApplicationFiled: December 5, 2007Publication date: September 4, 2008Applicant: FUJITSU LIMITEDInventors: Tadashi Nakatani, Anh Tuan Nguyen, Satoshi Ueda, Yu Yonezawa, Naoyuki Mishima
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Publication number: 20080180872Abstract: 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.Type: ApplicationFiled: January 23, 2008Publication date: July 31, 2008Applicants: FUJITSU LIMITED, FUJITSU MEDIA DEVICES LIMITEDInventors: Naoyuki Mishima, Yu Yonezawa, Takeaki Shimanouchi, Xiaoyu Mi, Takeshi Takano, Nobuhisa Aoki, Yuuta Nakaya