Patents by Inventor Koji Nii

Koji Nii 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).

  • Publication number: 20140070212
    Abstract: A semiconductor device having a capability of generating chip identification information includes: an SRAM macro having a plurality of memory cells arranged in rows and columns; a test address storage unit configured to store a test address; a self-diagnostic circuit configured to output the test address based on a result of confirmation of operation of the memory cell selected by the test address; and an identification information generation circuit configured to generate chip identification information based on the test address which is output by the self-diagnostic circuit.
    Type: Application
    Filed: September 10, 2013
    Publication date: March 13, 2014
    Applicant: RENESAS ELECTRONICS CORPORATION
    Inventors: Hidehiro FUJIWARA, Makoto YABUUCHI, Koji NII, Yoshikazu SAITO
  • Patent number: 8659969
    Abstract: By using a fact that a bit error in an on-chip embedded memory occurs at a random address, means for creating a chip-unique ID and utilizing this ID are provided. A controller having received a verification request from outside instructs a variable power supply circuit to decrease a voltage supplied to a memory to be lower than that at the normal operation time. When the voltage supplied to the memory is stabilized, the controller requests a memory test to a memory BIST. By using an address where an error occurs due to a result of the memory test, the controller creates the chip-unique ID and uses the ID as a response to the verification request.
    Type: Grant
    Filed: August 22, 2011
    Date of Patent: February 25, 2014
    Assignee: Renesas Electronics Corporation
    Inventors: Hidehiro Fujiwara, Koji Nii, Makoto Yabuuchi, Kazutami Arimoto
  • Patent number: 8630142
    Abstract: Cell power supply lines are arranged for memory cell columns, and adjust impedances or voltage levels of the cell power supply lines according to the voltage levels of bit lines in the corresponding columns, respectively. In the data write operation, the cell power supply line is forced into a floating state according to the bit line potential on a selected column and has the voltage level changed, and a latching capability of a selected memory cell is reduced to write data fast. Even with a low power supply voltage, a static semiconductor memory device that can stably perform write and read of data is implemented.
    Type: Grant
    Filed: June 8, 2012
    Date of Patent: January 14, 2014
    Assignee: Renesas Electronics Corporation
    Inventors: Koji Nii, Shigeki Obayashi, Hiroshi Makino, Koichiro Ishibashi, Hirofumi Shinohara
  • Patent number: 8441843
    Abstract: The invention provides a semiconductor integrated circuit device provided with an SRAM that satisfies the requirements for both the SNM and the write margin with a low supply voltage. The semiconductor integrated circuit device include: multiple static memory cells provided in correspondence with multiple word lines and multiple complimentary bit lines; multiple memory cell power supply lines that each supply an operational voltage to each of the multiple memory cells connected to the multiple complimentary bit lines each; multiple power supply circuits comprised of resistive units that each supply a power supply voltage to the memory cell power supply lines each; and a pre-charge circuit that supplies a pre-charge voltage corresponding to the power supply voltage to the complimentary bit lines, wherein the memory cell power supply lines are made to have coupling capacitances to thereby transmit a write signal on corresponding complimentary bit lines.
    Type: Grant
    Filed: October 31, 2011
    Date of Patent: May 14, 2013
    Assignee: Renesas Electronics Corporation
    Inventors: Noriaki Maeda, Yoshihiro Shinozaki, Masanao Yamaoka, Yasuhisa Shimazaki, Masanori Isoda, Koji Nii
  • Patent number: 8363456
    Abstract: To improve reliability of a semiconductor device having an SRAM. The semiconductor device has a memory cell including six n-channel type transistors and two p-channel type transistors formed over a silicon substrate. Over the silicon substrate, a first p well, a first n well, a second p well, a second n well, and a third p well are arranged in this order when viewed in a row direction. First and second positive-phase access transistors are disposed in the first p well, first and second driver transistors are disposed in the second p well, and first and second negative-phase access transistors are arranged in the third p well.
    Type: Grant
    Filed: December 22, 2010
    Date of Patent: January 29, 2013
    Assignee: Renesas Electronics Corporation
    Inventor: Koji Nii
  • Patent number: 8310883
    Abstract: A driver power supply circuit stepping down a power supply voltage is arranged at a power supply node of a word line driver. The driver power supply circuit includes a non-silicide resistance element of N+ doped polycrystalline silicon, and a pull-down circuit lowering a voltage level of the driver power supply node. The pull-down circuit includes a pull-down transistor having the same threshold voltage characteristics as a memory cell transistor pulling down a voltage level of the driver power supply node, and a gate control circuit adjusting at least a gate voltage of the pull-down transistor. The gate control circuit corrects the gate potential of the pull-down transistor in a manner linked to variations in threshold voltage of the memory cell transistor.
    Type: Grant
    Filed: July 28, 2011
    Date of Patent: November 13, 2012
    Assignee: Renesas Electronics Corporation
    Inventors: Makoto Yabuuchi, Koji Nii
  • Patent number: 8305836
    Abstract: First and second read word lines are provided in each set made of two adjacent rows. First, second, third, and fourth read bit lines are provided in each column. Each of the first and second read word lines is connected to memory cells in a corresponding one of the sets. Each of the first and third read bit lines is connected to a memory cell in one row in each of the sets, out of memory cells in a corresponding one of the columns. Each of the second and fourth read bit lines is connected to a memory cell in the other row in each of the sets, out of the memory cells in the corresponding one of the columns.
    Type: Grant
    Filed: May 19, 2011
    Date of Patent: November 6, 2012
    Assignee: Renesas Electronics Corporation
    Inventor: Koji Nii
  • Publication number: 20120243302
    Abstract: Cell power supply lines are arranged for memory cell columns, and adjust impedances or voltage levels of the cell power supply lines according to the voltage levels of bit lines in the corresponding columns, respectively. In the data write operation, the cell power supply line is forced into a floating state according to the bit line potential on a selected column and has the voltage level changed, and a latching capability of a selected memory cell is reduced to write data fast. Even with a low power supply voltage, a static semiconductor memory device that can stably perform write and read of data is implemented.
    Type: Application
    Filed: June 8, 2012
    Publication date: September 27, 2012
    Applicant: Renesas Electronics Corporation
    Inventors: Koji NII, Shigeki OBAYASHI, Hiroshi MAKINO, Koichiro ISHIBASHI, Hirofumi SHINOHARA
  • Patent number: 8238142
    Abstract: In a multipart SRAM memory cell of the present invention, an access transistor of a first port is disposed in a p-type well, and an access transistor of a second port is disposed in a p-type well. The gates of all of transistors disposed in a memory cell extend in the same direction. With the configuration, a semiconductor memory device having a low-power consumption type SRAM memory cell with an increased margin of variations in manufacturing, by which a bit line can be shortened in a multiport SRAM memory cell or an associative memory, can be obtained.
    Type: Grant
    Filed: May 18, 2011
    Date of Patent: August 7, 2012
    Assignee: Renesas Electronics Coporation
    Inventor: Koji Nii
  • Patent number: 8238192
    Abstract: A multiple-port semiconductor memory device capable of achieving a smaller circuit area is provided. A power supply line supplying an operation voltage of a memory cell is formed in an identical metal interconnection layer where word lines are formed and it is provided adjacent to and between corresponding first word line and second word line. Then, for example, when the same memory cell row is accessed, a voltage level of the power supply line is raised by a coupling capacitance of the word lines. Thus, even in identical-row-access, static noise margin in identical-row-access can be maintained to be as great as that in different-row-access. Therefore, for example, even when a size or the like of a driver transistor is not made larger, deterioration of static noise margin can be suppressed and a circuit area can be made smaller.
    Type: Grant
    Filed: February 14, 2011
    Date of Patent: August 7, 2012
    Assignee: Renesas Electronics Corporation
    Inventor: Koji Nii
  • Patent number: 8218390
    Abstract: Cell power supply lines are arranged for memory cell columns, and adjust impedances or voltage levels of the cell power supply lines according to the voltage levels of bit lines in the corresponding columns, respectively. In the data write operation, the cell power supply line is forced into a floating state according to the bit line potential on a selected column and has the voltage level changed, and a latching capability of a selected memory cell is reduced to write data fast. Even with a low power supply voltage, a static semiconductor memory device that can stably perform write and read of data is implemented.
    Type: Grant
    Filed: July 20, 2011
    Date of Patent: July 10, 2012
    Assignee: Renesas Electronics Corporation
    Inventors: Koji Nii, Shigeki Obayashi, Hiroshi Makino, Koichiro Ishibashi, Hirofumi Shinohara
  • Publication number: 20120087198
    Abstract: A level shift element adjusting a voltage level at the time of selection of a word line according to fluctuations in threshold voltage of a memory cell transistor is arranged for each word line. This level shift element lowers a driver power supply voltage, and transmits the level-shifted voltage onto a selected word line. The level shift element can be replaced with a pull-down element for pulling down the word line voltage according to the threshold voltage level of the memory cell transistor. In either case, the selected word line voltage level can be adjusted according to the fluctuations in threshold voltage of the memory cell transistor without using another power supply system. Thus, the power supply circuitry is not complicated, and it is possible to achieve a semiconductor memory device that can stably read and write data even with a low power supply voltage.
    Type: Application
    Filed: December 14, 2011
    Publication date: April 12, 2012
    Applicant: Renesas Electronics Corporation
    Inventors: Koji Nii, Shigeki Ohbayashi, Yasumasa Tsukamoto, Makoto Yabuuchi
  • Publication number: 20120044775
    Abstract: The invention provides a semiconductor integrated circuit device provided with an SRAM that satisfies the requirements for both the SNM and the write margin with a low supply voltage. The semiconductor integrated circuit device include: multiple static memory cells provided in correspondence with multiple word lines and multiple complimentary bit lines; multiple memory cell power supply lines that each supply an operational voltage to each of the multiple memory cells connected to the multiple complimentary bit lines each; multiple power supply circuits comprised of resistive units that each supply a power supply voltage to the memory cell power supply lines each; and a pre-charge circuit that supplies a pre-charge voltage corresponding to the power supply voltage to the complimentary bit lines, wherein the memory cell power supply lines are made to have coupling capacitances to thereby transmit a write signal on corresponding complimentary bit lines.
    Type: Application
    Filed: October 31, 2011
    Publication date: February 23, 2012
    Inventors: Noriaki Maeda, Yoshihiro Shinozaki, Masanao Yamaoka, Yasuhisa Shimazaki, Masanori Isoda, Koji Nii
  • Publication number: 20120044777
    Abstract: By using a fact that a bit error in an on-chip embedded memory occurs at a random address, means for creating a chip-unique ID and utilizing this ID are provided. A controller having received a verification request from outside instructs a variable power supply circuit to decrease a voltage supplied to a memory to be lower than that at the normal operation time. When the voltage supplied to the memory is stabilized, the controller requests a memory test to a memory BIST. By using an address where an error occurs due to a result of the memory test, the controller creates the chip-unique ID and uses the ID as a response to the verification request.
    Type: Application
    Filed: August 22, 2011
    Publication date: February 23, 2012
    Inventors: Hidehiro FUJIWARA, Koji NII, Makoto Yabuuchi, Kazutami Arimoto
  • Patent number: 8098533
    Abstract: A level shift element adjusting a voltage level at the time of selection of a word line according to fluctuations in threshold voltage of a memory cell transistor is arranged for each word line. This level shift element lowers a driver power supply voltage, and transmits the level-shifted voltage onto a selected word line. The level shift element can be replaced with a pull-down element for pulling down the word line voltage according to the threshold voltage level of the memory cell transistor. In either case, the selected word line voltage level can be adjusted according to the fluctuations in threshold voltage of the memory cell transistor without using another power supply system. Thus, the power supply circuitry is not complicated, and it is possible to achieve a semiconductor memory device that can stably read and write data even with a low power supply voltage.
    Type: Grant
    Filed: June 25, 2009
    Date of Patent: January 17, 2012
    Assignee: Renesas Electronics Corporation
    Inventors: Koji Nii, Shigeki Ohbayashi, Yasumasa Tsukamoto, Makoto Yabuuchi
  • Patent number: 8072799
    Abstract: The invention provides a semiconductor integrated circuit device provided with an SRAM that satisfies the requirements for both the SNM and the write margin with a low supply voltage. The semiconductor integrated circuit device include: multiple static memory cells provided in correspondence with multiple word lines and multiple complimentary bit lines; multiple memory cell power supply lines that each supply an operational voltage to each of the multiple memory cells connected to the multiple complimentary bit lines each; multiple power supply circuits comprised of resistive units that each supply a power supply voltage to the memory cell power supply lines each; and a pre-charge circuit that supplies a pre-charge voltage corresponding to the power supply voltage to the complimentary bit lines, wherein the memory cell power supply lines are made to have coupling capacitances to thereby transmit a write signal on corresponding complimentary bit lines.
    Type: Grant
    Filed: March 29, 2010
    Date of Patent: December 6, 2011
    Assignee: Renesas Electronics Corporation
    Inventors: Noriaki Maeda, Yoshihiro Shinozaki, Masanao Yamaoka, Yasuhisa Shimazaki, Masanori Isoda, Koji Nii
  • Publication number: 20110286291
    Abstract: A driver power supply circuit stepping down a power supply voltage is arranged at a power supply node of a word line driver. The driver power supply circuit includes a non-silicide resistance element of N+ doped polycrystalline silicon, and a pull-down circuit lowering a voltage level of the driver power supply node. The pull-down circuit includes a pull-down transistor having the same threshold voltage characteristics as a memory cell transistor pulling down a voltage level of the driver power supply node, and a gate control circuit adjusting at least a gate voltage of the pull-down transistor. The gate control circuit corrects the gate potential of the pull-down transistor in a manner linked to variations in threshold voltage of the memory cell transistor.
    Type: Application
    Filed: July 28, 2011
    Publication date: November 24, 2011
    Applicant: Renesas Electronics Corporation
    Inventors: Makoto YABUUCHI, Koji NII
  • Publication number: 20110273952
    Abstract: Cell power supply lines are arranged for memory cell columns, and adjust impedances or voltage levels of the cell power supply lines according to the voltage levels of bit lines in the corresponding columns, respectively. In the data write operation, the cell power supply line is forced into a floating state according to the bit line potential on a selected column and has the voltage level changed, and a latching capability of a selected memory cell is reduced to write data fast. Even with a low power supply voltage, a static semiconductor memory device that can stably perform write and read of data is implemented.
    Type: Application
    Filed: July 20, 2011
    Publication date: November 10, 2011
    Applicant: Renesas Electronics Corporation
    Inventors: Koji NII, Shigeki Obayashi, Hiroshi Makino, Koichiro Ishibashi, Hirofumi Shinohara
  • Publication number: 20110221007
    Abstract: In a multipart SRAM memory cell of the present invention, an access transistor of a first port is disposed in a p-type well, and an access transistor of a second port is disposed in a p-type well. The gates of all of transistors disposed in a memory cell extend in the same direction. With the configuration, a semiconductor memory device having a low-power consumption type SRAM memory cell with an increased margin of variations in manufacturing, by which a bit line can be shortened in a multiport SRAM memory cell or an associative memory, can be obtained.
    Type: Application
    Filed: May 18, 2011
    Publication date: September 15, 2011
    Applicant: Renesas Electronics Corporation
    Inventor: Koji Nii
  • Patent number: RE44242
    Abstract: A semiconductor memory having a memory cell structure capable of reducing soft error without complicating a circuit configuration. Specifically, an inverter (I1) consists of a NMOS transistor (N1) and a PMOS transistor (P1), and an inverter (I2) consists of a NMOS transistor (N2) and a PMOS transistor (P2). The inverters (I1, I2) are subjected to cross section. The NMOS transistor (N1) is formed within a P well region (PW0), and the NMOS transistor (N2) is formed within a P well region (PW1). The P well regions (PW0, PW1) are oppositely disposed with an N well region (NW) interposed therebetween.
    Type: Grant
    Filed: July 29, 2010
    Date of Patent: May 28, 2013
    Assignee: Renesas Electronics Corporation
    Inventor: Koji Nii