Patents by Inventor Hiroki Fujisawa

Hiroki Fujisawa 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: 7710172
    Abstract: A DLL circuit includes a delay line (CDL) (10) that delays a clock signal at a relatively coarse adjustment pitch, a delay line (FDL) (20) that delays the clock signal at a relatively fine adjustment pitch, and phase detecting circuits and counter control circuits that control delay amounts of the delay lines (10, 20). The counter control circuits control the delay line (10) by a linear search method, and control the delay line (20) by a binary search method. As a result, even when the number of bits of the count signal for adjusting the delay line (20) is increased, a delay amount can be determined at a high speed.
    Type: Grant
    Filed: July 9, 2008
    Date of Patent: May 4, 2010
    Assignee: Elpida Memory, Inc.
    Inventors: Koji Kuroki, Yasuhiro Takai, Hiroki Fujisawa
  • Publication number: 20100097096
    Abstract: A semiconductor device adjusting an impedance level of an output buffer, includes a replica buffer circuit including a circuit configuration substantially identical to the output buffer, a counter circuit changing an impedance code to vary an impedance level of the replica buffer, a latch circuit temporarily holding the impedance code in response to a control signal, and an end-determining circuit producing the control signal in response to a lapse of a predetermined period from issuance of a calibration command, irrespective of a fact that the replica buffer has not yet reached a desirable impedance level.
    Type: Application
    Filed: December 15, 2009
    Publication date: April 22, 2010
    Applicant: ELPIDA MEMORY, INC.
    Inventors: Fumiyuki Osanai, Hiroki Fujisawa
  • Patent number: 7688671
    Abstract: A semiconductor memory chip with an On-Die Termination (ODT) function is disclosed, which comprises a delay locked loop (DLL) circuit, a synchronous circuit, an asynchronous circuit, a select signal generator, and a selector. The DLL circuit is configured to produce a local clock signal in response to a clock signal when a clock enable (CKE) signal is asserted. The DLL circuit has a predetermined boost time. The select signal generator is configured to assert a select signal in consideration of the predetermined boost time. The selector is configured to select an output of the asynchronous circuit until the select signal is asserted but to select another output of the synchronous circuit after the select signal is asserted.
    Type: Grant
    Filed: October 19, 2006
    Date of Patent: March 30, 2010
    Assignee: Elpida Memory, Inc.
    Inventors: Yuki Hosoe, Hiroki Fujisawa
  • Publication number: 20100045359
    Abstract: To include a first replica buffer that has substantially the same circuit configuration as a pull-up circuit which constitutes an output buffer and a second replica buffer that has substantially the same circuit configuration as a pull-down circuit which constitutes the output buffer. When a first calibration command ZQCS is issued, either a control signal ACT1 or ACT2 is activated, and a calibration operation is performed for either the first replica buffer or the second replica buffer. When a second calibration command ZQCL is issued, both of the control signals ACT1, ACT2 are activated and the calibration operation is performed for both the first replica buffer and the second replica buffer.
    Type: Application
    Filed: November 3, 2009
    Publication date: February 25, 2010
    Applicant: ELPIDA MEMORY, INC.
    Inventors: Hideyuki Yoko, Hiroki Fujisawa
  • Patent number: 7668039
    Abstract: An address counter includes FIFO units and first and second command counters that control the groups. The first command counter has a first mode in which any one of input gates is conducted in response to a first internal command and a second mode in which a plurality of input gates are conducted in response to an internal command. The second command counter has a first mode in which any one of output gates is conducted in response to one of second and third internal commands and second mode in which corresponding output gates are each conducted in response to one of the second and third internal commands. Thereby, when tCCD is small, the first mode can be selected, and when the tCCD is large, the second mode can be selected.
    Type: Grant
    Filed: July 3, 2008
    Date of Patent: February 23, 2010
    Assignee: Elpida Memory, Inc.
    Inventor: Hiroki Fujisawa
  • Patent number: 7656186
    Abstract: A calibration circuit includes: replica buffers; an up-down counter that changes impedance codes of the replica buffers; latch circuits each holding the impedance codes; an end-determining circuit that activates the latch circuits in response to a completion of impedance adjustments of the replica buffers; and a 32 tCK cycle counter that forcibly activates the latch circuits in response to a lapse of a predetermined period since issuance of the calibration command. Thereby, even when the adjustment is not completed during one calibration period, a subsequent calibration operation can be executed from a previous point.
    Type: Grant
    Filed: June 26, 2008
    Date of Patent: February 2, 2010
    Assignee: Elpida Memory, Inc.
    Inventors: Fumiyuki Osanai, Hiroki Fujisawa
  • Patent number: 7639560
    Abstract: An output control signal generating circuit includes latch circuits that are connected in cascade, and a timing signal generating circuit that generates a timing signal to be supplied to the latch circuits, based on a second clock of which phase is advanced from the phase of a first clock used to take in a read command. The timing signal generating circuit delays the phase of a timing signal to be supplied to a relatively pre-stage latch circuit included in the latch circuits, from the phase of a timing signal to be supplied to a relatively latter stage latch circuit included in the latch circuits. With this arrangement, a latch margin of a first latch circuit does not depend on the cycle of an external clock. Accordingly, even when a clock has a very high speed, the output can be controlled correctly.
    Type: Grant
    Filed: August 26, 2008
    Date of Patent: December 29, 2009
    Assignee: Elpida Memory, Inc.
    Inventor: Hiroki Fujisawa
  • Patent number: 7630275
    Abstract: A latency counter includes: a point-shift type FIFO circuit having plural latch circuits connected in parallel, each latch circuit including an input gate and an output gate, and having an internal command MDRDT supplied in common to the input gates; and a selector that makes any one of the input gates and any one of the output gates conductive. The selector includes a counter that changes over between a selection operation of selecting the input gate and a selection operation of selecting the output gate, and the counter outputs a count value in a binary format synchronously with an internal clock ICLK. Because the binary-format counter is used in this way, the count value itself does not cause an error.
    Type: Grant
    Filed: August 6, 2007
    Date of Patent: December 8, 2009
    Assignee: Elpida Memory, Inc.
    Inventor: Hiroki Fujisawa
  • Publication number: 20090290445
    Abstract: A semiconductor device includes a latency setting circuit setting the latency, an input command circuit outputting a normal-phase (reverse-phase) command signal obtained by capturing an input command signal using a normal-phase (reverse-phase) clock, first and second counter circuits each including latch circuits for sequentially shifting the normal-phase (reverse-phase) command signal based on the normal-phase (reverse-phase) clock, a selector circuit controlling a signal path so that the normal-phase (reverse-phase) command signal is transmitted through the first (second) counter circuit when an even latency is set and the normal-phase (reverse-phase) command signal is transmitted so as to be shifted from the first (second) counter circuit to the second (first) counter circuit when an odd latency is set, and a control circuit controlling so that the latch circuits of the first (second) counter circuit are activated in response to the input command signal and stopped after an operation period is elapsed.
    Type: Application
    Filed: July 11, 2008
    Publication date: November 26, 2009
    Applicant: ELPIDA MEMORY INC.
    Inventors: Hiroto Kinoshita, Hiroki Fujisawa
  • Publication number: 20090289659
    Abstract: In a calibration control circuit, a first clock gate circuit restricts passage of reference update clocks during a calibration period so as to stop a first one of the reference update clocks and supplies the restricted reference update clocks as first update clocks CLK1 to both a hit determination circuit and a second clock gate circuit. The second clock gate circuit 110 passes through the first update clocks CLK1 until reception of a hit signal from the hit determination circuit and delivers second update clocks CLK2 to an up/down counter 106. The up/down counter 106 is operated by the second update clocks CLK2. With this structure, the second update clocks used for adjustment steps can be increased in number during the calibration period.
    Type: Application
    Filed: May 20, 2009
    Publication date: November 26, 2009
    Inventors: Shunji Kuwahara, Hiroki Fujisawa
  • Publication number: 20090289499
    Abstract: A semiconductor device is disclosed. A first power supply wiring for connecting between a first output circuit consisting of a predetermined number of output circuits and a first power supply pad which corresponds to the first output circuit, is connected via a resistor with a second power supply wiring for connecting between a second output circuit consisting of a predetermined number of output circuit and a second power supply pad which corresponds to the second output circuit. Thus, power supply noise that is to be propagated to certain output circuits via in-chip output power supply wirings can be reduced.
    Type: Application
    Filed: May 21, 2009
    Publication date: November 26, 2009
    Applicant: ELPIDA MEMORY, INC.
    Inventors: Takenori Sato, Hiroki Fujisawa
  • Publication number: 20090289677
    Abstract: A device in which a clock generation circuit is connected to a counter circuit for controlling operation timing of a DLL circuit or the like, and the counter circuit is intermittently operated by intermittently supplying a clock signal to the counter circuit from the clock generation circuit.
    Type: Application
    Filed: May 20, 2009
    Publication date: November 26, 2009
    Applicant: Elpida Memory, Inc.
    Inventors: Yoshio Mizukane, Hiroki Fujisawa
  • Publication number: 20090285048
    Abstract: To provide a counter circuit capable of accurately counting a high-frequency signal in which hazard or the like is easily generated. There are provided: a frequency dividing circuit that generates first and second frequency dividing clocks, which differ in phase to each other, based on a clock signal; a first counter that counts the first frequency dividing clock; a second counter that synchronizes with the second frequency dividing clock to fetch a count value of the first counter; and a selection circuit that exclusively selects count values of the first and second counters. According to the present invention, a relation of the count values between the first and second counters is kept always constant, and thus, even when hazard occurs, the count values are only made to jump and the count values do not fluctuate.
    Type: Application
    Filed: May 18, 2009
    Publication date: November 19, 2009
    Applicant: ELPIDA MEMORY, INC.
    Inventor: Hiroki FUJISAWA
  • Publication number: 20090285034
    Abstract: To provide a latency counter capable of increasing the signal quality of outputted internal commands. There is provided a point-shift FIFO circuit controlled by count values of a counter circuit. The point-shift FIFO circuit includes: a first wired-OR circuit that combines outputs of first latch circuits; a second wired-OR circuit that combines outputs of second latch circuits; a gate circuit that combines outputs of the first and second wired-OR circuits; and reset circuits that reset the first and second wired-OR circuits, respectively, based on the count value of the counter circuit. According to the present invention, as compared to a case that outputs of all the latch circuits are wired-OR connected, output loads are more reduced. Thus, a high signal quality can be obtained.
    Type: Application
    Filed: May 18, 2009
    Publication date: November 19, 2009
    Applicant: Elpida Memory, Inc.
    Inventor: Hiroki FUJISAWA
  • Publication number: 20090272649
    Abstract: A method for studying, determining or evaluating a pharmacological action of a test substance, the method including subjecting the brain tissue of an SART stressed animal administered with the test substance to an expression proteome analysis, where expression changes of NSF (N-ethylmaleimide sensitive fusion protein), which is or is not modified after translation, in the SART stressed animal administered with the test substance as compared with an SART stressed animal to which a test substance is not administered is used as an index.
    Type: Application
    Filed: September 5, 2007
    Publication date: November 5, 2009
    Applicant: NIPPON ZOKI PHARMACEUTICAL CO., LTD.
    Inventors: Kusuki Nishioka, Tomohiro Kato, Hiroki Fujisawa
  • Patent number: 7612579
    Abstract: An output circuit includes a counter circuit that generates an ODT control signal ODTa, plural driver circuits having the ODT function, a synchronizing circuit that synchronizes a signal transmitted from the counter circuit to the driver circuit with an internal clock DLL, a first selecting circuit that activates one of plural ODT selection signals ODTb and ODTc based on the ODT control signal ODTa, and a second selecting circuit that selects a driver circuit to be used out of the plural driver circuits based on the activated ODT selection signal. The first selecting circuit is provided between the counter circuit and the synchronizing circuit, and the second selecting circuit is provided between the synchronizing circuit and the driver circuit.
    Type: Grant
    Filed: August 16, 2007
    Date of Patent: November 3, 2009
    Assignee: Elpida Memory, Inc.
    Inventor: Hiroki Fujisawa
  • Patent number: 7595645
    Abstract: Impedance adjusting transistors are once inactivated on every occasion of changing an impedance adjusting code. After restoring the potential to an initially set potential by once inactivating the impedance adjusting transistors, the state of the transistors is switched according to the impedance adjusting code. By starting the potential from the initially set potential at the time of switching the state of the transistors, no switching noise is generated. Since no switching noise is generated, a comparator always carries out stable comparison and judgment and thus there is obtained a calibration circuit that ensures stable outputs.
    Type: Grant
    Filed: October 16, 2006
    Date of Patent: September 29, 2009
    Assignee: Elpida Memory, Inc.
    Inventors: Hiroki Fujisawa, Hideyuki Yoko
  • Patent number: 7580321
    Abstract: A synchronous semiconductor memory device of the present invention has a clock generator for generating a normal and a reverse phase clocks by dividing an external clock, a command decoder for decoding an external command and outputting a command signal; latency setting means capable of selectively setting an even or odd number latency within a range of a predetermined number of clock cycles of the external clock, a latency counter which includes two counter circuits for sequentially shifting the command signal captured using the normal and reverse phase clock and being capable of switching a signal path in response to the number of clock cycles, and first and second control means which controls counting of the clock cycles equivalent to the even or odd number latency by forming an appropriate signal path.
    Type: Grant
    Filed: February 19, 2008
    Date of Patent: August 25, 2009
    Assignee: Elpida Memory, Inc.
    Inventors: Hiroki Fujisawa, Shuichi Kubouchi, Koji Kuroki
  • Patent number: 7576579
    Abstract: A DLL circuit includes a first delay adjusting circuit that adjusts an amount of delay of a frequency-divided signal CK1, a second delay adjusting circuit that adjusts an amount of delay of a frequency-divided signal CK2, a synthesizing circuit that synthesizes outputs of these delay adjusting circuits to generate an internal clock signal, and supplies the internal clock signal to a real path, a clock driver that receives the output of the first delay adjusting circuit and supplies the output to a replica path, and a clock driver that receives the output of the second delay adjusting circuit. These clock drivers have substantially the same circuit configuration. Accordingly, even when the power supply voltage fluctuates, influences of the fluctuations on the respective frequency-divided signals are almost equal. Thus, deterioration of the function of the DLL circuit due to fluctuations of the power supply voltage can be prevented.
    Type: Grant
    Filed: August 23, 2007
    Date of Patent: August 18, 2009
    Assignee: Elpida Memory, Inc.
    Inventors: Hiroki Fujisawa, Ryuji Takishita
  • Patent number: 7569428
    Abstract: Disclosed is a method for manufacturing a method for manufacturing a semiconductor device which comprises a substrate, a semiconductor chip and a plurality of terminals. The method comprises preparing the substrate comprising an insulator which is formed with a plurality of signal lines, a plurality of power lines related to the plurality of signal lines and a plurality of ground lines related to the plurality of signal lines on the insulator in accordance with a predetermined layout. Each of the plurality of line groups comprises one of the power lines, one of the ground lines and one of the signal lines arranged between the one of the power lines and the one of the ground lines. Each of the plurality of line groups shares any one of the power line and the ground line with a neighboring line group of the plurality of line groups.
    Type: Grant
    Filed: September 25, 2006
    Date of Patent: August 4, 2009
    Assignee: Elpida Memory, Inc.
    Inventors: Satoshi Isa, Satoshi Itaya, Mitsuaki Katagiri, Fumiyuki Osanai, Hiroki Fujisawa