Patents by Inventor So WATANABE

So WATANABE 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).

  • Publication number: 20250070636
    Abstract: The present invention adjusts the surge voltage of a switching element to a prescribed value or lower while reducing switching loss in accordance with an operation condition. The present invention includes a gate driving circuit unit that drives a semiconductor switching element and a feedback current control unit that applies, to a gate G of the semiconductor switching element, a feedback current which is calculated by multiplying the change rate of electricity applied by the gate driving circuit unit to the semiconductor switching element by a prescribed gain, in which the change rate of electricity is the time change rate of the voltage and/or current applied to the semiconductor switching element; and the feedback current control unit adjusts the surge voltage of the semiconductor switching element by changing the gain in accordance with an operation condition of the semiconductor switching element.
    Type: Application
    Filed: October 21, 2022
    Publication date: February 27, 2025
    Inventors: Hangxian GAO, So WATANABE, Hiroshi SUZUKI
  • Publication number: 20140001512
    Abstract: A semiconductor device provides a gate electrode formed on a lateral face of a wide trench, and thereby the gate electrode is covered by a gate insulating layer and a thick insulating layer to be an inter layer. Therefore, a parasitic capacitance of the gate becomes small, and there is no potential variation of the gate since there is no floating p-layer so that a controllability of the dv/dt can be improved. In addition, the conductive layer between the gate electrodes can relax the electric field applied to the corner of the gate electrode. In consequence, compatibility of low loss and low noise and high reliability can be achieved.
    Type: Application
    Filed: August 30, 2013
    Publication date: January 2, 2014
    Applicant: Hitachi, Ltd.
    Inventors: So WATANABE, Mutsuhiro MORI, Taiga ARAI
  • Publication number: 20130020634
    Abstract: A semiconductor device includes: a first semiconductor layer of a first conductivity type; a second semiconductor layer of a second conductivity type on the first semiconductor layer; trenches in the first semiconductor layer; a semiconductor protruding part on the first semiconductor layer; a third semiconductor layer on the semiconductor protruding part; a fourth semiconductor layer on the third semiconductor layer; a gate insulating layer disposed along the trench; a first interlayer insulating layer disposed along the trench; a first conductive layer facing to the fourth semiconductor layer; a second conductive layer on the first interlayer insulating layer; a second interlayer insulating layer covering the second conductive layer; a third conductive layer on the third semiconductor layer and fourth semiconductor layer; a contacting part connecting the third conductive layer and third semiconductor layer; and a fourth conductive layer formed on the second semiconductor layer.
    Type: Application
    Filed: July 19, 2012
    Publication date: January 24, 2013
    Applicant: Hitachi, Ltd.
    Inventors: So WATANABE, Masaki Shiraishi, Hiroshi Suzuki, Mutsuhiro Mori
  • Publication number: 20110133718
    Abstract: A semiconductor device provides a gate electrode formed on a lateral face of a wide trench, and thereby the gate electrode is covered by a gate insulating layer and a thick insulating layer to be an inter layer. Therefore, a parasitic capacitance of the gate becomes small, and there is no potential variation of the gate since there is no floating p-layer so that a controllability of the dv/dt can be improved. In addition, the conductive layer between the gate electrodes can relax the electric field applied to the corner of the gate electrode. In consequence, compatibility of low loss and low noise and high reliability can be achieved.
    Type: Application
    Filed: December 2, 2010
    Publication date: June 9, 2011
    Applicant: Hitachi, Ltd.
    Inventors: So WATANABE, Mutsuhiro Mori, Taiga Arai