Patents by Inventor Hirokazu Yoshizawa

Hirokazu Yoshizawa 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: 20240077722
    Abstract: In a linked display system in which wireless communication connection between a first information device and a second information device has been established, when the first information device transmits text data to the second information device in a state of displaying content containing the text data and image data, the second information device displays the text data while the first information device stops displaying the text data and enlarges and displays the image data.
    Type: Application
    Filed: November 14, 2023
    Publication date: March 7, 2024
    Inventors: Megumi KURACHI, Masuo OKU, Hirokazu ISHII, Osamu KAWAMAE, Yasunobu HASHIMOTO, Kazuhiko YOSHIZAWA
  • Patent number: 7508258
    Abstract: Provided is a chopper amplifier circuit capable of eliminating an influence of a slew rate of an amplifier and suppressing spike generation to thereby obtain an output signal having little harmonic distortion. The chopper amplifier circuit according to the present invention includes: a first chopper circuit for chopping an input signal by a first pulse and a second pulse shifted from each other in phase by a half cycle, switching a relation of connection between an input terminal pair and an output terminal pair at a timing of the chopping, and outputting the input signal as a modulated signal; an amplifier for amplifying the modulated signal and outputting the modulated signal thus amplified as an amplified signal; a first sample hold circuit for holding the amplified signal at the first pulse and outputting the amplified signal at the second pulse; and a second sample hold circuit for holding the amplified signal at the second pulse and outputting the amplified signal at the first pulse.
    Type: Grant
    Filed: February 6, 2007
    Date of Patent: March 24, 2009
    Assignees: Seiko Instruments Inc., Gakkouhoujin Chikoujigakuen
    Inventors: Hirokazu Yoshizawa, Ryoichi Anzai, Toshiyuki Uchida, Akira Takeda, Minoru Ariyama, Atsushi Igarashi
  • Patent number: 7479826
    Abstract: Provided is a chopper amplifier circuit capable of reducing an offset voltage of a sensor bridge and temperature characteristics of the offset voltage. An offset adjusting voltage generation circuit for generating a voltage equal to an offset voltage of a sensor bridge and an offset temperature characteristics adjusting voltage generation circuit for generating a voltage having temperature characteristics equal to those of the offset voltage are provided. These output voltages are chopper-modulated and subtracted from a chopper-modulated output signal of the sensor bridge.
    Type: Grant
    Filed: August 4, 2006
    Date of Patent: January 20, 2009
    Assignees: Seiko Instruments Inc., Gakkouhoujin Chikoujigakuen
    Inventors: Hirokazu Yoshizawa, Ryoichi Anzai, Toshiyuki Uchida, Minoru Ariyama, Atsushi Igarashi, Akira Takeda
  • Publication number: 20070222509
    Abstract: Provided is a chopper amplifier circuit capable of eliminating an influence of a slew rate of an amplifier and suppressing spike generation to thereby obtain an output signal having little harmonic distortion. The chopper amplifier circuit according to the present invention includes: a first chopper circuit for chopping an input signal by a first pulse and a second pulse shifted from each other in phase by a half cycle, switching a relation of connection between an input terminal pair and an output terminal pair at a timing of the chopping, and outputting the input signal as a modulated signal; an amplifier for amplifying the modulated signal and outputting the modulated signal thus amplified as an amplified signal; a first sample hold circuit for holding the amplified signal at the first pulse and outputting the amplified signal at the second pulse; and a second sample hold circuit for holding the amplified signal at the second pulse and outputting the amplified signal at the first pulse.
    Type: Application
    Filed: February 6, 2007
    Publication date: September 27, 2007
    Inventors: Hirokazu Yoshizawa, Ryoichi Anzai, Toshiyuki Uchida, Akira Takeda, Minoru Ariyama, Atsushi Igarashi
  • Publication number: 20070146065
    Abstract: Provided is a chopper amplifier circuit capable of reducing an offset voltage of a sensor bridge and temperature characteristics of the offset voltage. An offset adjusting voltage generation circuit for generating a voltage equal to an offset voltage of a sensor bridge and an offset temperature characteristics adjusting voltage generation circuit for generating a voltage having temperature characteristics equal to those of the offset voltage are provided. These output voltages are chopper-modulated and subtracted from a chopper-modulated output signal of the sensor bridge.
    Type: Application
    Filed: August 4, 2006
    Publication date: June 28, 2007
    Inventors: Hirokazu Yoshizawa, Ryoichi Anzai, Toshiyuki Uchida, Minoru Ariyama, Atsushi Igarashi, Akira Takeda
  • Publication number: 20040130377
    Abstract: A switched capacitor amplifier circuit includes an operational amplifier; a plurality of switch circuits; a plurality of capacitors; and two input terminals; in which a standard voltage and a reference voltage are provided, and noise components of the standard voltage and the reference voltage are made in phase to reduce noises caused by offset voltage adjustment.
    Type: Application
    Filed: November 24, 2003
    Publication date: July 8, 2004
    Inventors: Akira Takeda, Hirokazu Yoshizawa
  • Patent number: 6713815
    Abstract: A semiconductor device is provided, which includes a pair of differential transistors that convert a voltage difference between a first input terminal and a second input terminal into a drain current difference between a first transistor and a second transistor and in which a voltage range of the first input terminal or the second input terminal is wide. A SOI structure MOSFET is used as each of the pair of differential transistors. The MOSFET includes a general MOSFET structure including a source region, a drain region, a well region between both the regions, a gate oxide film on an upper surface of the well region, and a gate electrode on the gate oxide film, and further includes a first conductivity type substrate region under the source region, the drain region and the well region through a buried oxide film.
    Type: Grant
    Filed: May 16, 2002
    Date of Patent: March 30, 2004
    Assignee: Seiko Instruments Inc.
    Inventors: Fumiyasu Utsunomiya, Hirokazu Yoshizawa
  • Patent number: 6542007
    Abstract: An inverter circuit is disclosed that prevents flow of a large feedthrough current. The inverter circuit includes depletion type MOS transistor combined with a resistor to impose a current limitation when a feedthrough current flows.
    Type: Grant
    Filed: November 21, 2001
    Date of Patent: April 1, 2003
    Assignee: Seiko Instruments Inc.
    Inventor: Hirokazu Yoshizawa
  • Publication number: 20020175373
    Abstract: A semiconductor device is provided, which includes a pair of differential transistors that convert a voltage difference between a first input terminal and a second input terminal into a drain current difference between a first transistor and a second transistor and in which a voltage range of the first input terminal or the second input terminal is wide. A SOI structure MOSFET is used as each of the pair of differential transistors. The MOSFET includes a general MOSFET structure including a source region, a drain region, a well region between both the regions, a gate oxide film on an upper surface of the well region, and a gate electrode on the gate oxide film, and further includes a first conductivity type substrate region under the source region, the drain region and the well region through a buried oxide film.
    Type: Application
    Filed: May 16, 2002
    Publication date: November 28, 2002
    Inventors: Fumiyasu Utsunomiya, Hirokazu Yoshizawa
  • Publication number: 20020153926
    Abstract: An inverter circuit is disclosed that prevents flow of a large feedthrough current. The inverter circuit includes depletion type MOS transistor combined with a resistor to impose a current limitation when a feedthrough current flows.
    Type: Application
    Filed: November 21, 2001
    Publication date: October 24, 2002
    Inventor: Hirokazu Yoshizawa
  • Patent number: 6437722
    Abstract: In a pipeline A/D converter circuit, the time at which outputs of MDACs of the A/D converter circuit change is shifted at respective stages, so that a cumulative error is avoided. In a resistance ladder circuit for supplying reference voltages to sub-A/D converter circuits of the pipeline A/D converter circuit, main resistors and auxiliary resistors are alternately connected in series to prepare the reference voltages, and the reference voltage supplied to the first stage MDAC is made different from the reference voltage supplied to the second and subsequent stage MDACs. In an embodiment, the auxiliary resistors have a resistance value of no more than one-half that of the main resistors to provide the offset.
    Type: Grant
    Filed: October 27, 2000
    Date of Patent: August 20, 2002
    Assignee: Seiko Instruments Inc.
    Inventor: Hirokazu Yoshizawa
  • Patent number: 6351163
    Abstract: A reset circuit includes an invertor having one control input terminal to which a positive supply voltage and a potential lower than GND are supplied, and an n-channel transistor having a gate terminal connected to an output terminal of the invertor, a source terminal connected to a potential lower than the GND and a drain terminal connected to the GND.
    Type: Grant
    Filed: April 28, 2000
    Date of Patent: February 26, 2002
    Assignee: Seiko Instruments Inc.
    Inventors: Hirokazu Yoshizawa, Masanao Hamaguchi
  • Patent number: 6288662
    Abstract: In a resistor ladder circuit for supplying reference voltages to sub-A/D converter circuits constituting a pipeline type A/D converter, the circuit is configured in such a way that main resistors are connected in series with auxiliary resistors in order to produce a plurality of reference voltages so that the reference voltages which are supplied to an MDAC in the first stage differ from those which are supplied to the MDACs in and after the second stage.
    Type: Grant
    Filed: June 29, 1999
    Date of Patent: September 11, 2001
    Assignee: Seiko Instruments Inc.
    Inventor: Hirokazu Yoshizawa
  • Patent number: 6037836
    Abstract: A switched-capacitor amplifier circuit produces accurate output signal even if the input signal varies rapidly at every sampling phase. Two capacitors having the same capacitance are connected, in series with the input of an operational amplifier circuit. A switching circuit is connected between a first terminal and ground terminal. The two capacitors are connected with the first terminal.
    Type: Grant
    Filed: October 23, 1998
    Date of Patent: March 14, 2000
    Assignee: Seiko Instruments Inc.
    Inventor: Hirokazu Yoshizawa
  • Patent number: 5982247
    Abstract: There is provided a CR oscillating circuit from which oscillation frequency is obtained as targeted, when MOS capacitors having large voltage dependency are used therein. The circuit is constructed such that bias voltage is applied always to the two MOS capacitors by connecting the two MOS, capacitors in series in the opposite direction from each other and by connecting further a MOSFET.
    Type: Grant
    Filed: October 23, 1998
    Date of Patent: November 9, 1999
    Assignee: Seiko Instruments Inc.
    Inventors: Hirokazu Yoshizawa, Kenichi Kobayashi