Patents by Inventor Naoaki Naka

Naoaki Naka 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: 8290734
    Abstract: A semiconductor integrated circuit including: a data input circuit inputting a data input signal from outside and outputting the signal; a comparison value register memorizing an expectation value of the output signal varying in accordance with an input to the data input circuit; and a comparing circuit comparing a value in accordance with a switching number of the output signal of the data input circuit and the expectation value, is provided.
    Type: Grant
    Filed: October 16, 2007
    Date of Patent: October 16, 2012
    Assignee: Fujitsu Semiconductor Limited
    Inventors: Shigeru Nishio, Naoaki Naka
  • Publication number: 20080116937
    Abstract: A semiconductor integrated circuit including: a data input circuit inputting a data input signal from outside and outputting the signal; a comparison value register memorizing an expectation value of the output signal varying in accordance with an input to the data input circuit; and a comparing circuit comparing a value in accordance with a switching number of the output signal of the data input circuit and the expectation value, is provided.
    Type: Application
    Filed: October 16, 2007
    Publication date: May 22, 2008
    Inventors: Shigeru Nishio, Naoaki Naka
  • Publication number: 20070146063
    Abstract: A differential amplifier circuit includes a first load coupled to a first reference potential, a first MOS transistor having a drain node coupled to the first load, a second load coupled to the first reference potential, a second MOS transistor having a drain node coupled to the second load, a first constant current source coupled between a second reference potential and the source nodes of the first MOS transistor and the second MOS transistor, a third MOS transistor having a source node coupled to the first load, a fourth MOS transistor having a source node the second load, and a second constant current source coupled between the second reference potential and the drain nodes of the third MOS transistor and the fourth MOS transistor, wherein the first and second MOS transistors are of a first conduction type, and the third and fourth MOS transistors are of a second conduction type.
    Type: Application
    Filed: February 24, 2006
    Publication date: June 28, 2007
    Inventors: Junko Nakamoto, Naoaki Naka
  • Patent number: 7003060
    Abstract: An output circuit of the present invention includes a data output circuit and a clock output circuit. The output circuit includes a first D-type flip-flop and a selector for selectively outputting an output from the first D-type flip-flop or second data according to a selection signal. The clock output circuit includes a second D-type flip-flop, a third D-type flip-flop, and a dummy selector circuit. The dummy selector circuit is connected to the second and third D-type flip-flops and outputs a clock signal by using the same elements as those of the selector in order to realize the same delay time as that of the selector.
    Type: Grant
    Filed: March 13, 2002
    Date of Patent: February 21, 2006
    Assignee: Fujitsu Limited
    Inventors: Naoaki Naka, Junko Nakamoto
  • Publication number: 20050044461
    Abstract: A semiconductor device test circuit that prevents unnecessary data from being inputted to a functional macro circuit at the time of testing the functional macro circuit. In a plurality of flip-flops connected in series, serial test pattern data latched by a flip-flop at a stage is latched by a flip-flop at the next stage in synchronization with a first clock signal. The test pattern data latched by flip-flops at all the stages is outputted to the functional macro circuit at once in synchronization with a second clock signal inputted to the flip-flops.
    Type: Application
    Filed: March 26, 2004
    Publication date: February 24, 2005
    Inventors: Akimitsu Ikeda, Naoaki Naka
  • Patent number: 6661274
    Abstract: In the level converter circuit, when input signal is L level, a first NMOS transistor and a first PMOS transistor P1 are turned on by a first power supply potential, a second power supply potential is output to a first output terminal, a second NMOS transistor is turned on, and thereby, a reference potential VSS is output to a second output terminal. On the other hand, when the input signal is H level, a third NMOS transistor is turned on, the reference potential is output to the first output terminal, a fourth NMOS transistor and a second PMOS transistor are turned on, and thereby, the first power supply potential VDH is output to the second output terminal.
    Type: Grant
    Filed: October 30, 2000
    Date of Patent: December 9, 2003
    Assignee: Fujitsu Limited
    Inventors: Naoaki Naka, Junko Nakamoto
  • Patent number: 6636109
    Abstract: An amplification circuit of the present invention includes a first MOS transistor having a gate to which a first input terminal for inputting a positive logic input signal or a reference potential is connected and a drain to which a first load is connected, a second MOS transistor having a gate to which a second input terminal for inputting a negative logic input signal, which composes differential input signals with the positive logic signal, or the reference potential is connected and a drain to which an output terminal and a second load are connected, and pairing up with the first MOS transistor, and a current source to which sources of the first and second MOS transistors are connected, for supplying a constant current when the difference in voltage between the first and second input terminals is in a predetermined range, and varying the current to be supplied when the difference in voltage is beyond the predetermined range.
    Type: Grant
    Filed: March 13, 2002
    Date of Patent: October 21, 2003
    Assignee: Fujitsu Limited
    Inventors: Naoaki Naka, Junko Nakamoto, Yanyan Qiao
  • Patent number: 6624625
    Abstract: The invented test equipment, includes a circuit under test including a first terminating resistance connected to a first terminal; a first test circuit for outputting a high-speed test signal to said circuit under test via the second terminal; a tester connecting its third terminal to the second terminal of said first test circuit when said first test circuit outputs the high-speed test signal, or connecting a second test circuit for outputting a low-speed test signal to said circuit under test via its third terminal when said first test circuit does not output the high-speed test signal; and a determination circuit for evaluating the outputted signal of said circuit under test. A wiring between the first terminating resistance, the first terminal, the second terminal, the third terminal, and the second terminating resistance is joined in this serial order, when said tester connects the second terminating resistance to the third terminal.
    Type: Grant
    Filed: March 12, 2002
    Date of Patent: September 23, 2003
    Assignee: Fujitsu Limited
    Inventor: Naoaki Naka
  • Publication number: 20030042973
    Abstract: An amplification circuit of the present invention includes a first MOS transistor having a gate to which a first input terminal for inputting a positive logic input signal or a reference potential is connected and a drain to which a first load is connected, a second MOS transistor having a gate to which a second input terminal for inputting a negative logic input signal, which composes differential input signals with the positive logic signal, or the reference potential is connected and a drain to which an output terminal and a second load are connected, and pairing up with the first MOS transistor, and a current source to which sources of the first and second MOS transistors are connected, for supplying a constant current when the difference in voltage between the first and second input terminals is in a predetermined range, and varying the current to be supplied when the difference in voltage is beyond the predetermined range.
    Type: Application
    Filed: March 13, 2002
    Publication date: March 6, 2003
    Applicant: Fujitsu Limited
    Inventors: Naoaki Naka, Junko Nakamoto, Yanyan Qiao
  • Publication number: 20030016031
    Abstract: The invented test equipment, comprises a circuit under test including a first terminating resistance connected to a first terminal; a first test circuit for outputting a high-speed test signal to said circuit under test via the second terminal; a tester connecting its third terminal to the second terminal of said first test circuit when said first test circuit outputs the high-speed test signal, or connecting a second test circuit for outputting a low-speed test signal to said circuit under test via its third terminal when said first test circuit does not output the high-speed test signal; and a determination circuit for evaluating the outputted signal of said circuit under test. A wiring between the first terminating resistance, the first terminal, the second terminal, the third terminal, and the second terminating resistance is joined in this serial order, when said tester connects the second terminating resistance to the third terminal.
    Type: Application
    Filed: March 12, 2002
    Publication date: January 23, 2003
    Applicant: Fujitsu Limited
    Inventor: Naoaki Naka
  • Publication number: 20020186801
    Abstract: An output circuit of the present invention includes a data output circuit and a clock output circuit. The output circuit includes a first D-type flip-flop and a selector for selectively outputting an output from the first D-type flip-flop or second data according to a selection signal. The clock output circuit includes a second D-type flip-flop, a third D-type flip-flop, and a dummy selector circuit. The dummy selector circuit is connected to the second and third D-type flip-flops and outputs a clock signal by using the same elements as those of the selector in order to realize the same delay time as that of the selector.
    Type: Application
    Filed: March 13, 2002
    Publication date: December 12, 2002
    Applicant: FUJITSU LIMITED
    Inventors: Naoaki Naka, Junko Nakamoto
  • Patent number: 6384682
    Abstract: A differential amplifier circuit comprising a pair of input MOS transistors, wherein inputs are supplied to the gates thereof, load circuits are connected to the drains thereof, and a current source is connected to the sources thereof, the current value of the current source is altered in line with variations in the characteristics of the input MOS transistors, thereby suppressing variations in the output level generated at the drain terminals of the input MOS transistors. In other words, unlike a conventional differential amplifier circuit, the current value of the current source is not kept to a uniform value, but rather is altered in accordance with the transistor characteristics generated by the manufacturing process.
    Type: Grant
    Filed: June 25, 2001
    Date of Patent: May 7, 2002
    Assignee: Fujitsu Limited
    Inventors: Junko Maeda, Naoaki Naka
  • Publication number: 20010038311
    Abstract: A differential amplifier circuit comprising a pair of input MOS transistors, wherein inputs are supplied to the gates thereof, load circuits are connected to the drains thereof, and a current source is connected to the sources thereof, the current value of the current source is altered in line with variations in the characteristics of the input MOS transistors, thereby suppressing variations in the output level generated at the drain terminals of the input MOS transistors. In other words, unlike a conventional differential amplifier circuit, the current value of the current source is not kept to a uniform value, but rather is altered in accordance with the transistor characteristics generated by the manufacturing process.
    Type: Application
    Filed: June 25, 2001
    Publication date: November 8, 2001
    Applicant: Fujitsu Limited
    Inventors: Junko Maeda, Naoaki Naka
  • Patent number: 6275107
    Abstract: A differential amplifier circuit comprising a pair of input MOS transistors, wherein inputs are supplied to the gates thereof, load circuits are connected to the drains thereof, and a current source is connected to the sources thereof, the current value of the current source is altered in line with variations in the characteristics of the input MOS transistors, thereby suppressing variations in the output level generated at the drain terminals of the input MOS transistors. In other words, unlike a conventional differential amplifier circuit, the current value of the current source is not kept to a uniform value, but rather is altered in accordance with the transistor characteristics generated by the manufacturing process.
    Type: Grant
    Filed: September 17, 1999
    Date of Patent: August 14, 2001
    Assignee: Fujitisu Limited
    Inventors: Junko Maeda, Naoaki Naka
  • Patent number: 5966044
    Abstract: A pull-up circuit includes a pull-up transistor of a P-channel type having a drain coupled to a bus via a terminal, a source, a gate and a back gate, and a control circuit controlling the pull-up transistor so that no currents flow in a first current path formed from the drain to the back gate and a second path formed from the drain to the source.
    Type: Grant
    Filed: November 4, 1997
    Date of Patent: October 12, 1999
    Assignee: Fujitsu Limited
    Inventor: Naoaki Naka
  • Patent number: 5936456
    Abstract: A power-supply circuit 121 generates a potential Vw which is approximately the higher of a power-supply potential VDD and a potential Vo at an output to set the potential Vw at an N-well of a pMOS pull-up transistor Qu equal to or higher than the potential at the source S and the drain D of the pMOS transistor Qu. The power-supply circuit 122 generates a potential Vs approximately equal to VDD--Vth when Vo<VDD, and turns off when Vo>VDD to prevent a current from flowing from the output OUT through the pMOS transistor Qu to the power-supply potential VDD, where Vth is the threshold voltage of the MOS transistors.
    Type: Grant
    Filed: September 17, 1997
    Date of Patent: August 10, 1999
    Assignee: Fujitsu Limited
    Inventor: Naoaki Naka