Patents by Inventor Choshu Ito

Choshu Ito 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: 10808333
    Abstract: A method and system for designing an integrated circuit layout are disclosed. In one embodiment, the method includes generating a stem cell library with stem cell layouts, wherein each stem cell layout includes an analog core area where a device element resides, and abutment boundaries on left, right, top, and bottom sides of the analog core area. The method also includes mapping device elements in a schematic netlist to the stem cell layouts in the stem cell library. In addition, the method includes placing and routing the mapped device elements to optimize a layout for the schematic netlist.
    Type: Grant
    Filed: January 8, 2019
    Date of Patent: October 20, 2020
    Assignee: Totic Technology Inc.
    Inventors: Choshu Ito, Dan Bui
  • Publication number: 20190211475
    Abstract: A method and system for designing an integrated circuit layout are disclosed. In one embodiment, the method includes generating a stem cell library with stem cell layouts, wherein each stem cell layout includes an analog core area where a device element resides, and abutment boundaries on left, right, top, and bottom sides of the analog core area. The method also includes mapping device elements in a schematic netlist to the stem cell layouts in the stem cell library. In addition, the method includes placing and routing the mapped device elements to optimize a layout for the schematic netlist.
    Type: Application
    Filed: January 8, 2019
    Publication date: July 11, 2019
    Inventors: Choshu Ito, Dan Bui
  • Patent number: 9239896
    Abstract: A design methodology which prevents functional failure caused by CDM ESD events. A transistor model is used to model the final states of cells, and a simulator is then used to identify invulnerable cells. Cells that are potential failure sites are then identified. The cells which have been identified as being potential victims are replaced by the previously-identified invulnerable cells that have the identical logic function. On the other hand, if a cell with identical function cannot be found, an invulnerable buffer cell (that will not effect logic function) can be inserted in front of the potential victim transistor as protection. By replacing all the potential victim cells with cells which have been determined to be invulnerable, the resulting design will be guaranteed to be CDM ESD tolerant.
    Type: Grant
    Filed: October 21, 2008
    Date of Patent: January 19, 2016
    Assignee: Avago Technologies General IP (Singapore) Pte. Ltd.
    Inventors: Choshu Ito, Tze Wee Chen, William Loh
  • Patent number: 8929497
    Abstract: Described embodiments calibrate a sampling phase adjustment of a receiver. An analog-to-digital converter generates samples of a received signal at a sample phase. A phase detector selects a window of n samples. If the window includes a Nyquist pattern, a bang-bang trap is enabled that iteratively, for each transition between a first consecutive bit and a second consecutive bit in the Nyquist pattern, samples the received signal at a zero crossing between the first and second consecutive bits and determines the transition polarity. Based on the transition polarity and the zero crossing sample value, the bang-bang trap determines whether the sample phase is correct. If Nyquist patterns are absent from the window, a margin phase detector determines a target voltage margin value and a voltage of a cursor bit of the window. Based on the target voltage margin and voltage, the margin phase detector determines whether the sample phase is correct.
    Type: Grant
    Filed: March 16, 2012
    Date of Patent: January 6, 2015
    Assignee: LSI Corporation
    Inventors: Erik V. Chmelar, Choshu Ito
  • Patent number: 8923382
    Abstract: Described embodiments adapt one or more taps of a decision feedback equalizer of a receiver by setting a reference voltage for each of one or more data recovery comparators to a corresponding predetermined initial value. The data recovery comparators generate a bit value for each sample of a received signal. A tap adaptation module of the receiver selects a window of n received bit samples. The tap adaptation module iteratively, for each of the one or more data recovery comparators, tracks (i) a detected number of bits having a logic 0 value, and (ii) a detected number of bits having a logic 1 value. The tap adaptation module adjusts, based on a ratio of the detected number of bits having a logic 0 value to the detected number of bits having a logic 1 value, the reference voltage for the corresponding data recovery comparator by a predetermined step amount.
    Type: Grant
    Filed: March 16, 2012
    Date of Patent: December 30, 2014
    Assignee: LSI Corporation
    Inventors: Choshu Ito, Erik V. Chmelar
  • Patent number: 8798981
    Abstract: A method for simulating a response of a circuit to an ESD input stimulus applied to the circuit includes the steps of: receiving a description of the circuit into a circuit simulation program, the circuit including at least one mutual inductance element indicative of magnetic coupling in the circuit; generating a linear approximation of nonlinear elements in the circuit at respective DC bias points of the nonlinear elements; obtaining a frequency domain transfer function of the circuit; obtaining a time domain impulse response of the circuit as a function of the frequency domain transfer function; integrating the time domain impulse response to yield a step response of the circuit, the step response being indicative of a response of the circuit to the ESD input stimulus; and analyzing the step response of the circuit to determine whether the circuit will operate within prescribed parameters corresponding to the circuit.
    Type: Grant
    Filed: June 23, 2008
    Date of Patent: August 5, 2014
    Assignee: LSI Corporation
    Inventors: Choshu Ito, William Loh
  • Publication number: 20130243127
    Abstract: Described embodiments calibrate a sampling phase adjustment of a receiver. An analog-to-digital converter generates samples of a received signal at a sample phase. A phase detector selects a window of n samples. If the window includes a Nyquist pattern, a bang-bang trap is enabled. The bang-bang trap iteratively, for each transition between a first consecutive bit and a second consecutive bit in the Nyquist pattern, samples the received signal at a zero crossing between the first and second consecutive bits and determines the transition polarity. Based on the transition polarity and the zero crossing sample value, the bang-bang trap determines whether the sample phase is correct. If Nyquist patterns are absent from the window, a margin phase detector determines a target voltage margin value and a voltage of a cursor bit of the window. Based on the target voltage margin value and the voltage of the cursor bit, the margin phase detector determines whether the sample phase is correct.
    Type: Application
    Filed: March 16, 2012
    Publication date: September 19, 2013
    Inventors: Erik V. Chmelar, Choshu Ito
  • Publication number: 20130243070
    Abstract: Described embodiments adapt one or more taps of a decision feedback equalizer of a receiver by setting a reference voltage for each of one or more data recovery comparators to a corresponding predetermined initial value. The data recovery comparators generate a bit value for each sample of a received signal. A tap adaptation module of the receiver selects a window of n received bit samples. The tap adaptation module iteratively, for each of the one or more data recovery comparators, tracks (i) a detected number of bits having a logic 0 value, and (ii) a detected number of bits having a logic 1 value. The tap adaptation module adjusts, based on a ratio of the detected number of bits having a logic 0 value to the detected number of bits having a logic 1 value, the reference voltage for the corresponding data recovery comparator by a predetermined step amount.
    Type: Application
    Filed: March 16, 2012
    Publication date: September 19, 2013
    Inventors: Choshu Ito, Erik V. Chmelar
  • Publication number: 20130243056
    Abstract: Described embodiments provide a method of recovering timing data from a received signal. An analog-to-digital converter (ADC) of a receiver generates an actual ADC value for each bit sample of a received signal. Each bit sample occurs at an associated sample phase of the receiver. A margin phase detector of the receiver recovers timing information from the received signal by determining a target voltage margin value. The margin phase detector selects a window of n received bit samples, where n is a positive integer, and determines a voltage of a cursor bit of the selected window of bit samples. The margin phase detector determines, based on the target voltage margin value and the voltage of the cursor bit, whether the sample phase is correct. If the sample phase is incorrect, the margin phase detector adjusts the sample phase of the receiver by a predetermined amount.
    Type: Application
    Filed: March 16, 2012
    Publication date: September 19, 2013
    Inventors: Erik V. Chmelar, Choshu Ito
  • Publication number: 20130243107
    Abstract: Described embodiments recover timing data from a received signal. An analog-to-digital converter (ADC) generates a value for each sample of the signal at a sample phase. A phase detector selects a window of n received bit samples, where n is a positive integer. If the bit window includes any Nyquist patterns, the phase detector enables a bang-bang trap. The bang-bang-trap iteratively, for each bit transition between a first consecutive bit and a second consecutive bit in the Nyquist patterns, samples the received signal at a zero crossing between the first and second consecutive bits and determines the polarity of the bit transition. Based on the polarity of the bit transition and the sample value at the zero crossing, the bang-bang trap determines whether the sample phase of the bit sample for the second consecutive bit is correct. If the sample phase is incorrect, the bang-bang trap adjusts the sample phase.
    Type: Application
    Filed: March 16, 2012
    Publication date: September 19, 2013
    Inventors: Erik V. Chmelar, Choshu Ito
  • Patent number: 8258016
    Abstract: Embodiments of the invention include a semiconductor integrated circuit package that includes a substrate having an integrated circuit die attached thereto. The package includes a ESD shield attached to the substrate. The ESD shield configured to increase the ESD hardness of the package. The ESD shield can further serve to stiffen the package to prevent warping and operate as a heat spreader.
    Type: Grant
    Filed: December 17, 2008
    Date of Patent: September 4, 2012
    Assignee: LSI Corporation
    Inventors: Choshu Ito, William M. Loh, Rajagopalan Parthasarathy
  • Patent number: 8121186
    Abstract: Various embodiments of the present invention provide systems and methods for signal equalization, and in some cases analog to digital conversion. For example, an analog to digital converter is disclosed that includes a comparator bank that receives a reference indicator and is operable to provide a decision output based at least in part on a comparison of an analog input with a reference threshold corresponding to the reference indicator. A range selection filter is included that has a first adjustment calculation circuit and a second adjustment calculation circuit. The first adjustment calculation circuit is operable to calculate a first adjustment feedback value based at least in part on a speculation that the decision output is a first logic level, and the second adjustment calculation circuit is operable to calculate a second adjustment feedback value based at least in part on a speculation that the decision output is a second logic level.
    Type: Grant
    Filed: June 6, 2008
    Date of Patent: February 21, 2012
    Assignee: LSI Corporation
    Inventors: Erik Chmelar, Choshu Ito, William Loh
  • Patent number: 7973692
    Abstract: Various embodiments of the present invention provide systems and methods for analog to digital conversion. For example, a latch based analog to digital converter is disclosed that includes a first interleave with a set of comparators, a selector circuit and a latch. The set of comparators is operable to compare an analog input with respective reference voltages, and is synchronized to a clock phase. The selector circuit is operable to select an output of one of the set of comparators based at least in part on a selector input. A first interleave output is derived from the selected output. The latch receives a second interleave output from a second interleave and is transparent when the clock phase is asserted. The selector input includes an output of the latch.
    Type: Grant
    Filed: June 6, 2008
    Date of Patent: July 5, 2011
    Assignee: LSI Corporation
    Inventors: Erik Chmelar, Choshu Ito, William Loh
  • Patent number: 7956790
    Abstract: Various embodiments of the present invention provide systems and methods for analog to digital conversion. For example, a retimed analog to digital converter is disclosed that includes a first set of sub-level interleaves and a second set of sub-level interleaves. The first set of sub-level interleaves includes a first sub-level interleave with a first set of comparators synchronized to a first clock phase, and a second sub-level interleave with a second set of comparators synchronized to a second clock phase. The second set of sub-level interleaves includes a third sub-level interleave with a third set of comparators synchronized to a third clock phase, and a fourth sub-level interleave with a fourth set of comparators synchronized to a fourth clock phase.
    Type: Grant
    Filed: June 6, 2008
    Date of Patent: June 7, 2011
    Assignee: LSI Corporation
    Inventors: Erik Chmelar, Choshu Ito, William Loh
  • Patent number: 7944655
    Abstract: An ESD protection circuit for protecting a host circuit coupled to a signal pad from an ESD event occurring at the signal pad includes at least one MEMS switch which is electrically connected to the signal pad. The MEMS switch includes a first contact structure adapted for connection to the signal pad, and a second contact structure adapted for connection to a voltage supply source. The first and second contact structures are coupled together during the ESD event for shunting an ESD current from the signal pad to the voltage supply source. The first and second contact structures are electrically isolated from one another in the absence of the ESD event. At least one of the first and second contact structures includes a passivation layer for reducing contact adhesion between the first and second contact structures.
    Type: Grant
    Filed: May 28, 2008
    Date of Patent: May 17, 2011
    Assignee: LSI Corporation
    Inventors: Tze Wee Chen, William Loh, Choshu Ito
  • Patent number: 7777996
    Abstract: A system and method for protecting a circuit. The system includes a protection circuit that includes an inverter and a capacitor coupled to the inverter. The inverter and the capacitor are implemented using logic circuits of a circuit core, and the inverter shunts electrostatic discharge ESD current through the capacitor. According to the system and method disclosed herein, because the protection circuit shunt circuit shunts ESD current using logic circuits of the circuit core, ESD protection is achieved while not requiring large FETs. Also, the protection circuit protects circuits against ESD events that conventional FET cannot protect.
    Type: Grant
    Filed: June 30, 2005
    Date of Patent: August 17, 2010
    Assignee: LSI Corporation
    Inventors: William M. Loh, Ken Doniger, Payman Zarkesh-Ha, Jau-Wen Chen, Choshu Ito
  • Publication number: 20100194616
    Abstract: Various embodiments of the present invention provide systems and methods for analog to digital conversion. For example, a retimed analog to digital converter is disclosed that includes a first set of sub-level interleaves and a second set of sub-level interleaves. The first set of sub-level interleaves includes a first sub-level interleave with a first set of comparators synchronized to a first clock phase, and a second sub-level interleave with a second set of comparators synchronized to a second clock phase. The second set of sub-level interleaves includes a third sub-level interleave with a third set of comparators synchronized to a third clock phase, and a fourth sub-level interleave with a fourth set of comparators synchronized to a fourth clock phase.
    Type: Application
    Filed: June 6, 2008
    Publication date: August 5, 2010
    Inventors: Erik Chmelar, Choshu Ito, William Loh
  • Publication number: 20100195776
    Abstract: Various embodiments of the present invention provide systems and methods for analog to digital conversion. For example, a latch based analog to digital converter is disclosed that includes a first interleave with a set of comparators, a selector circuit and a latch. The set of comparators is operable to compare an analog input with respective reference voltages, and is synchronized to a clock phase. The selector circuit is operable to select an output of one of the set of comparators based at least in part on a selector input. A first interleave output is derived from the selected output. The latch receives a second interleave output from a second interleave and is transparent when the clock phase is asserted. The selector input includes an output of the latch.
    Type: Application
    Filed: June 6, 2008
    Publication date: August 5, 2010
    Inventors: Erik Chmelar, Choshu Ito, William Loh
  • Publication number: 20100100859
    Abstract: A design methodology which prevents functional failure caused by CDM ESD events. A transistor model is used to model the final states of cells, and a simulator is then used to identify invulnerable cells. Cells that are potential failure sites are then identified. The cells which have been identified as being potential victims are replaced by the previously-identified invulnerable cells that have the identical logic function. On the other hand, if a cell with identical function cannot be found, an invulnerable buffer cell (that will not effect logic function) can be inserted in front of the potential victim transistor as protection. By replacing all the potential victim cells with cells which have been determined to be invulnerable, the resulting design will be guaranteed to be CDM ESD tolerant.
    Type: Application
    Filed: October 21, 2008
    Publication date: April 22, 2010
    Applicant: LSI CORPORATION
    Inventors: Choshu Ito, Tze Wee Chen, William Loh
  • Patent number: 7696915
    Abstract: An ADC circuit includes multiple comparators and a controller coupled to the comparators. Each of the comparators is operative to generate an output indicative of a difference between a first signal representative of an input signal applied to the ADC circuit and a corresponding reference signal. The controller is operative to perform at least one of: (i) activating a subset of the comparators during a given sample period being; and (ii) controlling levels of the corresponding reference signals of the comparators as a function of a level of the input signal. A number of active comparators during the given sample period is no greater than one less than a number of regions into which the input signal is quantized.
    Type: Grant
    Filed: April 24, 2008
    Date of Patent: April 13, 2010
    Assignee: Agere Systems Inc.
    Inventors: Erik Chmelar, Choshu Ito