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).
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Publication number: 20240077722Abstract: 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: ApplicationFiled: November 14, 2023Publication date: March 7, 2024Inventors: Megumi KURACHI, Masuo OKU, Hirokazu ISHII, Osamu KAWAMAE, Yasunobu HASHIMOTO, Kazuhiko YOSHIZAWA
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Patent number: 7508258Abstract: 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: GrantFiled: February 6, 2007Date of Patent: March 24, 2009Assignees: Seiko Instruments Inc., Gakkouhoujin ChikoujigakuenInventors: Hirokazu Yoshizawa, Ryoichi Anzai, Toshiyuki Uchida, Akira Takeda, Minoru Ariyama, Atsushi Igarashi
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Patent number: 7479826Abstract: 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: GrantFiled: August 4, 2006Date of Patent: January 20, 2009Assignees: Seiko Instruments Inc., Gakkouhoujin ChikoujigakuenInventors: Hirokazu Yoshizawa, Ryoichi Anzai, Toshiyuki Uchida, Minoru Ariyama, Atsushi Igarashi, Akira Takeda
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Publication number: 20070222509Abstract: 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: ApplicationFiled: February 6, 2007Publication date: September 27, 2007Inventors: Hirokazu Yoshizawa, Ryoichi Anzai, Toshiyuki Uchida, Akira Takeda, Minoru Ariyama, Atsushi Igarashi
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Publication number: 20070146065Abstract: 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: ApplicationFiled: August 4, 2006Publication date: June 28, 2007Inventors: Hirokazu Yoshizawa, Ryoichi Anzai, Toshiyuki Uchida, Minoru Ariyama, Atsushi Igarashi, Akira Takeda
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Publication number: 20040130377Abstract: 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: ApplicationFiled: November 24, 2003Publication date: July 8, 2004Inventors: Akira Takeda, Hirokazu Yoshizawa
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Patent number: 6713815Abstract: 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: GrantFiled: May 16, 2002Date of Patent: March 30, 2004Assignee: Seiko Instruments Inc.Inventors: Fumiyasu Utsunomiya, Hirokazu Yoshizawa
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Patent number: 6542007Abstract: 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: GrantFiled: November 21, 2001Date of Patent: April 1, 2003Assignee: Seiko Instruments Inc.Inventor: Hirokazu Yoshizawa
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Publication number: 20020175373Abstract: 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: ApplicationFiled: May 16, 2002Publication date: November 28, 2002Inventors: Fumiyasu Utsunomiya, Hirokazu Yoshizawa
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Publication number: 20020153926Abstract: 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: ApplicationFiled: November 21, 2001Publication date: October 24, 2002Inventor: Hirokazu Yoshizawa
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Patent number: 6437722Abstract: 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: GrantFiled: October 27, 2000Date of Patent: August 20, 2002Assignee: Seiko Instruments Inc.Inventor: Hirokazu Yoshizawa
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Patent number: 6351163Abstract: 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: GrantFiled: April 28, 2000Date of Patent: February 26, 2002Assignee: Seiko Instruments Inc.Inventors: Hirokazu Yoshizawa, Masanao Hamaguchi
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Patent number: 6288662Abstract: 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: GrantFiled: June 29, 1999Date of Patent: September 11, 2001Assignee: Seiko Instruments Inc.Inventor: Hirokazu Yoshizawa
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Patent number: 6037836Abstract: 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: GrantFiled: October 23, 1998Date of Patent: March 14, 2000Assignee: Seiko Instruments Inc.Inventor: Hirokazu Yoshizawa
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Patent number: 5982247Abstract: 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: GrantFiled: October 23, 1998Date of Patent: November 9, 1999Assignee: Seiko Instruments Inc.Inventors: Hirokazu Yoshizawa, Kenichi Kobayashi