Patents by Inventor Tatsuhiro Mizumasa

Tatsuhiro Mizumasa 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).

  • Patent number: 8648617
    Abstract: According to the following disclosure, disclosed is a semiconductor device including: an internal circuit configured to receive and output a signal current; a current mirror unit outputting a copied current corresponding to the signal current; and a test pad from which the copied current is taken out.
    Type: Grant
    Filed: February 7, 2011
    Date of Patent: February 11, 2014
    Assignee: Fujitsu Semiconductor Limited
    Inventors: Yuji Maruyama, Tatsuhiro Mizumasa, Takayuki Nakashiro, Shigeru Gotoh, Takayuki Yano, Susumu Koshinuma, Shunsuke Taniguchi, Yuki Yanagisako
  • Publication number: 20110221466
    Abstract: According to the following disclosure, disclosed is a semiconductor device including: an internal circuit configured to receive and output a signal current; a current mirror unit outputting a copied current corresponding to the signal current; and a test pad from which the copied current is taken out.
    Type: Application
    Filed: February 7, 2011
    Publication date: September 15, 2011
    Applicant: FUJITSU SEMICONDUCTOR LIMITED
    Inventors: Yuji MARUYAMA, Tatsuhiro Mizumasa, Takayuki Nakashiro, Shigeru Gotoh, Takayuki Yano, Susumu Koshinuma, Shunsuke Taniguchi, Yuki Yanagisako
  • Patent number: 7764116
    Abstract: A cutoff frequency adjusting method adjusts a cutoff frequency of a GmC filter circuit which has a capacitor and an Operational Transconductance Amplifier (OTA) circuit with a controllable Gm value. A Gm value of the OTA circuit is detected based on a voltage of the capacitor which is charged by an output of the OTA circuit, and a cutoff frequency of the GmC circuit is set to a desired value by controlling the Gm value of the OTA circuit constant based on the detected Gm value.
    Type: Grant
    Filed: April 29, 2008
    Date of Patent: July 27, 2010
    Assignee: Fujitsu Semiconductor Limited
    Inventor: Tatsuhiro Mizumasa
  • Publication number: 20090027115
    Abstract: A cutoff frequency adjusting method adjusts a cutoff frequency of a GmC filter circuit which has a capacitor and an Operational Transconductance Amplifier (OTA) circuit with a controllable Gm value. A Gm value of the OTA circuit is detected based on a voltage of the capacitor which is charged by an output of the OTA circuit, and a cutoff frequency of the GmC circuit is set to a desired value by controlling the Gm value of the OTA circuit constant based on the detected Gm value.
    Type: Application
    Filed: April 29, 2008
    Publication date: January 29, 2009
    Applicant: FUJITSU LIMITED
    Inventor: Tatsuhiro MIZUMASA
  • Patent number: 7310507
    Abstract: A filter circuit, having a plurality of selectable impedance elements, that has a cutoff frequency dependent on a selected impedance element, comprises a pulse generation circuit that supplies a variable frequency pulse with a successively increasing or decreasing frequency to an input of the filter circuit; and an impedance element selection unit that checks the attenuation of the output pulse of the filter circuit corresponding with the input of the variable frequency pulse and selects the plurality of impedance elements on the basis of the position of a pulse that is attenuated to or below a reference value.
    Type: Grant
    Filed: January 28, 2005
    Date of Patent: December 18, 2007
    Assignee: Fujitsu Limited
    Inventors: Tatsuhiro Mizumasa, Koji Nozoe
  • Patent number: 6999020
    Abstract: A frequency detecting circuit 10 detects frequency of a sampling pulse SP, and outputs the detected frequency as a detection value VOUT. A current adjusting circuit 20 adjusts a power supply current Ivd to be supplied to an AD converter 30 in accordance with the detection value VOUT. The power supply current Ivd varies continuously so as to follow the sampling frequency. As a result, an optimum power supply current Ivd can always be supplied in accordance with the operating frequency of the AD converter 30. That is, power consumption of the AD converter 30 can be reduced. Since the power supply current Ivd can be adjusted in accordance with the sampling frequency, it is possible to form the AD converter 30 that has a wide frequency band and allows great versatility.
    Type: Grant
    Filed: May 28, 2004
    Date of Patent: February 14, 2006
    Assignee: Fujitsu Limited
    Inventors: Tatsuhiro Mizumasa, Atsushi Hitaka
  • Publication number: 20050176393
    Abstract: A filter circuit, having a plurality of selectable impedance elements, that has a cutoff frequency dependent on a selected impedance element, comprises a pulse generation circuit that supplies a variable frequency pulse with a successively increasing or decreasing frequency to an input of the filter circuit; and an impedance element selection unit that checks the attenuation of the output pulse of the filter circuit corresponding with the input of the variable frequency pulse and selects the plurality of impedance elements on the basis of the position of a pulse that is attenuated to or below a reference value.
    Type: Application
    Filed: January 28, 2005
    Publication date: August 11, 2005
    Inventors: Tatsuhiro Mizumasa, Koji Nozoe
  • Publication number: 20050162301
    Abstract: A frequency detecting circuit 10 detects frequency of a sampling pulse SP, and outputs the detected frequency as a detection value VOUT. A current adjusting circuit 20 adjusts a power supply current lvd to be supplied to an AD converter 30 in accordance with the detection value VOUT. The power supply current lvd varies continuously so as to follow the sampling frequency. As a result, an optimum power supply current lvd can always be supplied in accordance with the operating frequency of the AD converter 30. That is, power consumption of the AD converter 30 can be reduced. Since the power supply current lvd can be adjusted in accordance with the sampling frequency, it is possible to form the AD converter 30 that has a wide frequency band and allows great versatility.
    Type: Application
    Filed: May 28, 2004
    Publication date: July 28, 2005
    Inventors: Tatsuhiro Mizumasa, Atsushi Hitaka
  • Patent number: 6901566
    Abstract: A semiconductor integrated circuit has a first circuit region using a first power supply voltage and a second circuit region using a second power supply voltage different from the first power supply voltage. The first circuit region is manufactured by a first design rule in accordance with the first power supply voltage, and the second circuit region is manufactured by a second design rule in accordance with the second power supply voltage.
    Type: Grant
    Filed: March 18, 2002
    Date of Patent: May 31, 2005
    Assignee: Fujitsu Limited
    Inventor: Tatsuhiro Mizumasa
  • Publication number: 20030070149
    Abstract: A semiconductor integrated circuit has a first circuit region using a first power supply voltage and a second circuit region using a second power supply voltage different from the first power supply voltage. The first circuit region is manufactured by a first design rule in accordance with the first power supply voltage, and the second circuit region is manufactured by a second design rule in accordance with the second power supply voltage.
    Type: Application
    Filed: March 18, 2002
    Publication date: April 10, 2003
    Applicant: Fujitsu Limited
    Inventor: Tatsuhiro Mizumasa