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: 8751694
    Abstract: A data transfer operation completion detection circuit including a first counter for performing a shifting operation in response to the generation of a read initiation signal, a second counter for performing a shifting operation in response to the generation of a burst completion signal, and an SR latch circuit for generating a read enable signal in response to the burst completion signal being generated when the count value of the first counter matches the count value of the second counter. The completion of a read operation or another data transfer operation is thus detected based on a read initiation signal reception history; therefore, it is possible to detect whether all read operations are complete at a given time even if a new read command is received while a read operation or the like is in progress.
    Type: Grant
    Filed: March 13, 2013
    Date of Patent: June 10, 2014
    Inventor: Hiroki Fujisawa
  • Patent number: 8724416
    Abstract: Disclosed herein is a semiconductor device having self-refresh modes in which a refresh operation of storage data is periodically performed asynchronously with an external clock signal. The semiconductor device performs the refresh operation on n memory cells in response to an auto-refresh command. The semiconductor device periodically performs the refresh operation on m memory cells included in the memory cell array during the self-refresh mode, where m is smaller than n.
    Type: Grant
    Filed: July 26, 2012
    Date of Patent: May 13, 2014
    Inventor: Hiroki Fujisawa
  • Patent number: 8713247
    Abstract: A data transfer operation completion detection circuit including a first counter for performing a shifting operation in response to the generation of a read initiation signal, a second counter for performing a shifting operation in response to the generation of a burst completion signal, and an SR latch circuit for generating a read enable signal in response to the burst completion signal being generated when the count value of the first counter matches the count value of the second counter. The completion of a read operation or another data transfer operation is thus detected based on a read initiation signal reception history; therefore, it is possible to detect whether all read operations are complete at a given time even if a new read command is received while a read operation or the like is in progress.
    Type: Grant
    Filed: September 18, 2006
    Date of Patent: April 29, 2014
    Inventor: Hiroki Fujisawa
  • Publication number: 20140111271
    Abstract: A semiconductor device includes a boosting circuit that boosts an internal power supply voltage in a boosting range according to an external power supply voltage, an external voltage-level comparison circuit that compares the external power supply voltage and a predetermined reference voltage, and a variable resistor circuit that includes a variable resistor connected to an output terminal of the boosting circuit. The variable resistor circuit controls a resistance value of the variable resistor based on a comparison result of the external voltage-level comparison circuit.
    Type: Application
    Filed: December 27, 2013
    Publication date: April 24, 2014
    Applicant: Elpida Memory, Inc.
    Inventors: Hiroki FUJISAWA, Shuichi KUBOUCHI, Hitoshi TANAKA
  • Patent number: 8699256
    Abstract: A bit memory circuit of an antifuse element set includes two antifuse elements of which logical states are changed from an insulation state to a conductive state when a program voltage is applied. 1-bit data is represented by the logical states of the two antifuse elements. The two antifuse elements are collectively controlled by one decoder circuit. When writing data, the decoder circuit simultaneously performs insulation-breakdown on the two antifuse elements by simultaneously connecting the two antifuse elements to program voltage lines, respectively.
    Type: Grant
    Filed: September 7, 2010
    Date of Patent: April 15, 2014
    Assignee: Elpida Memory, Inc.
    Inventors: Shuichi Kubouchi, Hiroki Fujisawa
  • Patent number: 8686567
    Abstract: A semiconductor device includes a lower wiring layer, having signal lines and power supply lines extending in a Y-direction; an upper wiring layer having signal lines and power supply lines extending in an X-direction; via conductors provided in first overlap regions where corresponding signal lines overlap each other; and via conductors provided in second overlap regions where corresponding power supply lines overlap each other. The width in the X-direction of the first regions is wider than the widths in the X-direction of the second regions. Therefore, in the first regions, a plurality of via conductors can be provided. Moreover, the power supply lines are divided in the Y-direction to avoid interference with the first regions. On a plurality of lower-layer lines, two vias are placed at a minimum pitch containing one via.
    Type: Grant
    Filed: November 17, 2011
    Date of Patent: April 1, 2014
    Inventors: Kiyotaka Endo, Kazuteru Ishizuka, Hiroki Fujisawa
  • Publication number: 20140078852
    Abstract: For example, a semiconductor device includes a first latency counter, which selects whether to give an odd-cycle latency to an internal command signal; and a second latency counter, which gives a latency to an internal command signal at intervals of two cycles. The latency counters are connected in series. Since the number of bits in control information, which is used to set a latency, is smaller than the types of settable latency as a result, it is possible to reduce wiring density.
    Type: Application
    Filed: November 22, 2013
    Publication date: March 20, 2014
    Applicant: Elpida Memory, Inc.
    Inventor: Hiroki Fujisawa
  • Patent number: 8633758
    Abstract: A semiconductor device includes a boosting circuit that boosts an internal power supply voltage in a boosting range according to an external power supply voltage, an external voltage-level comparison circuit that compares the external power supply voltage and a predetermined reference voltage, and a variable resistor circuit that includes a variable resistor connected to an output terminal of the boosting circuit. The variable resistor circuit controls a resistance value of the variable resistor based on a comparison result of the external voltage-level comparison circuit.
    Type: Grant
    Filed: March 11, 2011
    Date of Patent: January 21, 2014
    Assignee: Elpida Memory, Inc.
    Inventors: Hiroki Fujisawa, Shuichi Kubouchi, Hitoshi Tanaka
  • Patent number: 8630129
    Abstract: A semiconductor device is provided with a control circuit generating a plurality of first control signals indicating timings at which column switches conduct at the time of reading and a plurality of second control signals indicating timings at which the column switches conduct at the time of writing. The control circuit activates the plurality of first control signals such that timing at which the data read from each of memory cell arrays arrives at a FIFO circuit after reception of a read instruction from outside is the same in each bank and activates the plurality of second control signals such that the column switches match a timing at which write data input from outside to a first data input/output terminal arrives at the corresponding column switch.
    Type: Grant
    Filed: November 23, 2011
    Date of Patent: January 14, 2014
    Assignee: Elpida Memory, Inc.
    Inventors: Hiroki Fujisawa, Yuuji Motoyama
  • Patent number: 8618853
    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: Grant
    Filed: June 14, 2013
    Date of Patent: December 31, 2013
    Inventors: Yoshio Mizukane, Hiroki Fujisawa
  • Patent number: 8611177
    Abstract: For example, a semiconductor device includes a first latency counter, which selects whether to give an odd-cycle latency to an internal command signal; and a second latency counter, which gives a latency to an internal command signal at intervals of two cycles. The latency counters are connected in series. Since the number of bits in control information, which is used to set a latency, is smaller than the types of settable latency as a result, it is possible to reduce wiring density.
    Type: Grant
    Filed: October 24, 2011
    Date of Patent: December 17, 2013
    Assignee: Elpida Memory, Inc.
    Inventor: Hiroki Fujisawa
  • Patent number: 8611176
    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: Grant
    Filed: September 16, 2011
    Date of Patent: December 17, 2013
    Assignee: Elpida Memory, Inc.
    Inventor: Hiroki Fujisawa
  • Patent number: 8576656
    Abstract: A latency counter includes an input selecting circuit that selects one of a plurality of signal paths and supplies an internal command to the selected signal path, a shift circuit that switches a correspondence relation between the signal paths and a latch circuit, and an output selecting circuit that causes the internal command taken in the latch circuit to be output. The input selection circuit includes a timing control circuit allocated to each of the signal paths. The timing control circuit includes an SR latch circuit that is set by the internal command and is reset in response to deactivation of a corresponding count value. Therefore, it becomes possible to suppress shortening of an active period of the internal command that is output from the input selecting circuit.
    Type: Grant
    Filed: September 3, 2010
    Date of Patent: November 5, 2013
    Assignee: Elpida Memory, Inc.
    Inventor: Hiroki Fujisawa
  • Publication number: 20130278310
    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: June 14, 2013
    Publication date: October 24, 2013
    Inventors: Yoshio MIZUKANE, Hiroki FUJISAWA
  • Patent number: 8553489
    Abstract: For example, a semiconductor device includes latch circuits, whose input nodes are connected to an input selection circuit and whose output nodes are connected to an output selection circuit; and a control circuit, which controls the input selection circuit and the output selection circuit. The control circuit includes a shift register to generate an input pointer signal and a binary counter to generate an output pointer signal. The input selection circuit selects one of the latch circuits on the basis of a value of the input pointer signal. The output selection circuit selects one of the latch circuits on the basis of a value of the output pointer signal. Therefore, it is possible to prevent a hazard from occurring in the input selection circuit, as well as to reduce the number of signal lines that transmit the output pointer signal.
    Type: Grant
    Filed: October 24, 2011
    Date of Patent: October 8, 2013
    Assignee: Elpida Memory, Inc.
    Inventors: Hiroki Fujisawa, Yuuji Motoyama
  • Patent number: 8537626
    Abstract: A semiconductor device includes a data input/output circuit connected to the memory cell array via a sense circuit, and an access control circuit that controls access to the memory cell array. The access control circuit includes: a first signal unit outputting a first signal for activating or inactivating a word line; a second signal unit outputting a second signal for activating or inactivating a bit line and the sense circuit; a third signal unit outputting a third signal for starting or stopping a supply of an overdrive voltage to the sense circuit; and a fourth signal unit outputting a fourth signal for inactivating the word line. The period during which the third signal remains activated is determined in accordance with the magnitude of an external voltage. In the fourth signal unit, the timing to generate the fourth signal is determined independently of the magnitude of the external voltage.
    Type: Grant
    Filed: October 24, 2011
    Date of Patent: September 17, 2013
    Assignee: Elpida Memory, Inc.
    Inventors: Hiroki Fujisawa, Kazuhisa Ureshino
  • Publication number: 20130205157
    Abstract: A data transfer operation completion detection circuit including a first counter for performing a shifting operation in response to the generation of a read initiation signal, a second counter for performing a shifting operation in response to the generation of a burst completion signal, and an SR latch circuit for generating a read enable signal in response to the burst completion signal being generated when the count value of the first counter matches the count value of the second counter. The completion of a read operation or another data transfer operation is thus detected based on a read initiation signal reception history; therefore, it is possible to detect whether all read operations are complete at a given time even if a new read command is received while a read operation or the like is in progress.
    Type: Application
    Filed: March 13, 2013
    Publication date: August 8, 2013
    Applicant: Elpida Memory, Inc.
    Inventor: Hiroki FUJISAWA
  • Patent number: 8493110
    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: Grant
    Filed: July 15, 2011
    Date of Patent: July 23, 2013
    Assignee: Elpida Memory, Inc.
    Inventors: Yoshio Mizukane, Hiroki Fujisawa
  • Patent number: 8461867
    Abstract: To include an output terminal, unit buffers, and plural output-wiring paths that respectively connect the unit buffers and the output terminal. The output wiring paths have individual output wiring sections individually allocated to corresponding unit buffers. Unit buffers corresponding to these output wiring paths are common output wiring sections shared by the output wiring paths, and are connected to the output terminal without via a common output wiring section having a higher resistance value than those of the individual output wiring sections. Accordingly, an deviation of impedance due to a parasitic resistance between the output terminal and the unit buffers is suppressed.
    Type: Grant
    Filed: September 10, 2010
    Date of Patent: June 11, 2013
    Assignee: Elpida Memory, Inc.
    Inventors: Shunji Kuwahara, Hiroki Fujisawa
  • Patent number: 8427856
    Abstract: The present invention efficiently decides line failure and contact failure in a semiconductor device. The semiconductor device has a plurality of bit line groups in which connection with local I/O lines is controlled by the same column selection signal line. A failure detecting circuit compares a first data group read from a first bit line group and a second data group read from a second bit line group to detect whether or not connection failure (contact failure) with the column selection signal line occurs in one of the first and second bit line groups.
    Type: Grant
    Filed: September 27, 2011
    Date of Patent: April 23, 2013
    Assignee: Elpida Memory, Inc.
    Inventors: Shingo Mitsubori, Hiroki Fujisawa