Patents Represented by Attorney E. Eric Hoffman
  • Patent number: 7671401
    Abstract: A method, apparatus, and system in which an embedded memory fabricated in accordance with a conventional logic process includes one or more electrically-alterable non-volatile memory cells, each having a programming transistor, a read transistor and a control capacitor, which share a common floating gate electrode. The under-diffusion of the source/drain regions of the programming transistor and control capacitor are maximized. In one embodiment, the source/drain regions of the programming transistor are electrically shored by transistor punch-through (or direct contact).
    Type: Grant
    Filed: October 28, 2005
    Date of Patent: March 2, 2010
    Assignee: Mosys, Inc.
    Inventors: Gang-feng Fang, Dennis Sinitsky, Wingyu Leung
  • Patent number: 7564283
    Abstract: An automatic calibration scheme is provided, which calibrates the equivalent taps per period ETT/P every time a delay lock loop is used. More specifically, a digital phase shifter is used to measure equivalent taps per period ETT/P. Alternately, the digital phase shifter is used to directly measure the signal delay through a clock phase shifter of the delay lock loop, thereby directly determining the high frequency and low frequency overhead constants.
    Type: Grant
    Filed: April 30, 2004
    Date of Patent: July 21, 2009
    Assignee: XILINX, Inc.
    Inventors: John D. Logue, Alvin Y. Ching, Wei Guang Lu
  • Patent number: 7549139
    Abstract: A method of operating a programmable logic device includes the steps of using a full VDD supply voltage to operate a first set of active blocks of the programmable logic device, and using a reduced supply voltage (e.g., 0.9 VDD) to operate a second set of active blocks of the programmable logic device. A timing analysis is performed to determine the maximum available timing slack in each active block. Active blocks having a smaller timing slack are grouped in the first set, and are coupled to receive the full VDD supply voltage. Active blocks having a larger timing slack are grouped in the second set, and are coupled to receive the reduced VDD supply voltage. As a result, the active blocks in the second set exhibit reduced power consumption, without adversely affecting the overall speed of the programmable logic device.
    Type: Grant
    Filed: February 20, 2004
    Date of Patent: June 16, 2009
    Assignee: XILINX, Inc.
    Inventors: Tim Tuan, Jan L. deJong, Kameswara K. Rao, Robert O. Conn
  • Patent number: 7504854
    Abstract: A method of operating a programmable logic device, including the steps of using a full VDD supply voltage to operate one or more active blocks of the programmable logic device, and using a reduced supply voltage (e.g., ½ VDD) to operate one or more inactive blocks of the programmable logic device. The full VDD supply voltage and reduced supply voltage can be provided to the blocks of the programmable logic device through high-voltage n-channel transistors. A boosted voltage, greater than VDD, is applied to the gate of an n-channel transistor to provide the full VDD supply voltage to an active block. A standby voltage, less than VDD, is applied to the gate of an n-channel transistor to provide the reduced supply voltage to an inactive block. The inactive blocks can be determined during run time and/or design time of the programmable logic device.
    Type: Grant
    Filed: February 20, 2004
    Date of Patent: March 17, 2009
    Assignee: Xilinx, Inc.
    Inventors: Kevin T. Look, Michael J. Hart, Tim Tuan, Kameswara K. Rao, Robert O. Conn
  • Patent number: 7290201
    Abstract: A clock management system receives an input clock signal having rising edges and falling edges, a first set of data values associated with the rising edges of the input clock signal, and a second set of data values associated with the falling edges of the input clock signal. The clock management system provides a first clock and a second clock in response to the input clock signal. The first clock has a first set of edges that are synchronous with the rising edges of the input clock signal. The second clock has a second set of edges that are synchronous with the falling edges of the input clock signal. The first set of data values are latched in response to the first set of edges of the first clock. The second set of data values are latched in response to the second set of edges of the second clock.
    Type: Grant
    Filed: November 12, 2003
    Date of Patent: October 30, 2007
    Assignee: XILINX, Inc.
    Inventor: Gareth D. Edwards
  • Patent number: 7281082
    Abstract: A method and structure for configuring a programmable logic device (PLD) from a serial peripheral interface (SPI) based serial memory. The type of the SPI memory is initially identified by the PLD. The PLD then selects the appropriate read command in response to the SPI memory type. The PLD then issues the read command to the SPI memory. In response, the SPI memory continuously provides a set of configuration data to the PLD. The PLD is configured in response to the configuration data. The PLD can identify the SPI memory type in response to control signals on pins of the PLD. Alternately, the PLD can identify the SPI memory type by performing a search. The search can include issuing a plurality of known read commands to the SPI memory, and then determining which read command causes the SPI memory to respond.
    Type: Grant
    Filed: March 26, 2004
    Date of Patent: October 9, 2007
    Assignee: Xilinx, Inc.
    Inventor: Steven K. Knapp
  • Patent number: 7280421
    Abstract: A configuration circuit includes a latch and a dedicated non-volatile memory cell. The non-volatile memory cell is initially programmed or erased. The latch is then set to store a first logic value by coupling the latch to a first voltage supply terminal in response to an activated control signal. When the control signal is de-activated, the latch is de-coupled from the first voltage supply terminal and coupled to the non-volatile memory cell. If the non-volatile memory cell is programmed, the latch is coupled to a second voltage supply terminal, thereby storing a second logic value in the latch. If the non-volatile memory cell is erased, the latch is isolated from the second voltage supply terminal, and the first logic value remains stored in the latch. The latch can also be directly written through one or more access transistors, thereby facilitating testing.
    Type: Grant
    Filed: July 6, 2006
    Date of Patent: October 9, 2007
    Assignee: Xilinx, Inc.
    Inventors: Phillip A. Young, Sunhom Paak
  • Patent number: 7240320
    Abstract: A method of implementing a design on a programmable logic device (PLD) includes generating a database that identifies correspondence between resources and programming frames of the PLD. A first PLD design is compiled, wherein the first design uses a first set of resources in a first manner. Costs associated with using the first set of resources of the first design in the first manner are reduced. A second PLD design is then compiled, applying the reduced costs associated with using the first set of resources. A second set of resources required to compile the second design is identified, wherein the second set of resources is not used in the same manner as the first set of resources. A set of programming frames associated with the second set of resources is identified. Costs associated with using a third set of resources associated with the set of programming frames are increased.
    Type: Grant
    Filed: November 16, 2004
    Date of Patent: July 3, 2007
    Assignee: Xilinx, Inc.
    Inventors: Stephen M. Trimberger, Austin H. Lesea, Bernard J. New
  • Patent number: 7227378
    Abstract: A method of partially reconfiguring an IC having programmable modules that includes the steps of reading a frame of configuration information from the configuration memory array; modifying at least part of the configuration information, thereby creating a modified frame of configuration information; and overwriting the existing frame of configuration information in the configuration memory array with the modified frame, thereby partially reconfiguring the IC.
    Type: Grant
    Filed: April 7, 2005
    Date of Patent: June 5, 2007
    Assignee: Xilinx, Inc.
    Inventors: Brandon J. Blodget, Scott P. McMillan, Philip B. James-Roxby, Prasanna Sundararajan, Eric R. Keller, Derek R. Curd, Punit S. Kalra, Richard J. LeBlanc, Vincent P. Eck
  • Patent number: 7187742
    Abstract: A digital clock manager is provided. The digital clock manager generates an output clock signal that causes a skewed clock signal to be synchronized with a reference clock signal. Furthermore, the digital clock manager generates a frequency adjusted clock signal that is synchronized with the output clock signal during concurrence periods. The digital clock manager includes a delay lock loop and a digital frequency synthesizer. The delay lock loop generates a synchronizing clock signal that is provided to the digital frequency synthesizer. The output clock signal lags the synchronizing clock signal by a DLL output delay. Similarly, the frequency adjusted clock signal lags the synchronizing clock signal by a DFS output delay. By matching the DLL output delay to the DFS output delay, the digital clock manager synchronizes the output clock signal and the frequency adjusted clock signal.
    Type: Grant
    Filed: October 6, 2000
    Date of Patent: March 6, 2007
    Assignee: Xilinx, Inc.
    Inventors: John D. Logue, Andrew K. Percey, F. Erich Goetting
  • Patent number: 7157951
    Abstract: A delay line for a digital clock manager includes a tap delay structure and a trim delay structure. The trim delay structure includes a first buffer coupled to receive a clock signal from the tap delay structure, and in response, provide a delayed clock signal to a set of clock lines. The trim delay structure also includes a capacitive trim unit having a plurality of capacitive trim elements tapped off the set of clock lines. The capacitive trim elements are selectively enabled or disabled, thereby introducing additional delay to the delayed clock signal on the set of clock lines. Each capacitive trim element can include a transmission gate structure, which is turned on to introduce significant junction capacitance to the set of clock lines. The trim delay structure can also include a second buffer adapted to buffer the delayed clock signal on the set of clock lines.
    Type: Grant
    Filed: April 30, 2004
    Date of Patent: January 2, 2007
    Assignee: Xilinx, Inc.
    Inventors: Shawn K. Morrison, Raymond C. Pang
  • Patent number: 7149997
    Abstract: A method of routing a design on a programmable logic device (PLD) includes generating a database that identifies the correspondence between routing resources of the PLD and programming frames of the PLD. A first set of programming frames required to implement the logic of the design is identified, and the cost associated with using the first set of programming frames is eliminated. A second set of programming frames that are not used to implement the logic of the design is also identified, and the cost associated with using the second set of programming frames is maximized. Interconnect networks of the design are then routed, taking into account the costing of the programming frames. When a programming frame from the second set is used, the cost associated with using this programming frame is eliminated. This method minimizes used programming frames and maximizes unused programming frames, thus reducing PLD configuration time.
    Type: Grant
    Filed: October 15, 2004
    Date of Patent: December 12, 2006
    Assignee: Xilinx, Inc.
    Inventors: Jay T. Young, Jeffrey V. Lindholm, Ian L. McEwen
  • Patent number: 7109734
    Abstract: An integrated circuit (IC) includes multiple embedded test circuits that all include a ring oscillator coupled to a test load. The test load either is a direct short in the ring oscillator or else is a interconnect load that is representative of one of the interconnect layers in the IC. A model equation is defined for each embedded test circuit, with each model equation specifying the output delay of its associated embedded test circuit as a function of Front End OF the Line (FEOL) and Back End Of the Line (BEOL) parameters. The model equations are then solved for the various FEOL and BEOL parameters as functions of the test circuit output delays. Finally, measured output delay values are substituted in to these parameter equations to generate actual values for the various FEOL and BEOL parameters, thereby allowing any areas of concern to be quickly and accurately identified.
    Type: Grant
    Filed: December 18, 2003
    Date of Patent: September 19, 2006
    Assignee: Xilinx, Inc.
    Inventors: Xiao-Jie Yuan, Michael J. Hart, Zicheng G. Ling, Steven P. Young
  • Patent number: 7103685
    Abstract: A method and system for processing a plurality of multi-bit configuration words for configuring a programmable logic device. One or more of bits of the multi-bit configuration words are identified as “Don't Care” configuration bits that do not affect the functionality of the programmable logic device. These “Don't Care” configuration bits may or may not be related to the specific configuration of the programmable logic device. A lossy compression operation is performed on the multi-bit configuration words thereby creating a compressed data set. The identified “Don't Care” configuration bits are used during the compression operation. For example, the compression operation may include (1) maintaining a compression buffer of previously compressed configuration words, and (2) comparing configuration words to be compressed with the configuration words in the compression buffer, wherein the “Don't Care” configuration bits are deemed to result in matches during the comparison.
    Type: Grant
    Filed: January 16, 2004
    Date of Patent: September 5, 2006
    Assignee: Xilinx, Inc.
    Inventor: Stephen M. Trimberger
  • Patent number: 7098689
    Abstract: A method of operating a programmable logic device, including the steps of enabling resources of the programmable logic device being used in a circuit design implemented by the programmable logic device, and disabling unused or inactive resources of the programmable logic device that are not being used in the circuit design. The step of disabling can include de-coupling the unused or inactive resources from one or more power supply terminals. Alternatively, the step of disabling can include regulating a supply voltage applied to the unused or inactive resources. The step of disabling can be performed in response to configuration data bits stored by the programmable logic device and/or in response to user controlled signals. The step of disabling can be initiated during design time and/or run time of the programmable logic device.
    Type: Grant
    Filed: September 19, 2003
    Date of Patent: August 29, 2006
    Assignee: Xilinx, Inc.
    Inventors: Tim Tuan, Kameswara K. Rao, Robert O. Conn
  • Patent number: 7098710
    Abstract: A delay locked loop includes a primary delay line having a plurality of series-connected delay elements, wherein each of the delay elements operates in response to a supply voltage provided on a voltage supply line. When the delay locked loop is configured to operate in response to an input clock signal having a relatively high frequency, the voltage supply line is coupled to receive a first supply voltage. When the delay locked loop is configured to operate in response to an input clock signal having a relatively low frequency, the voltage supply line is coupled to receive a second supply voltage, which is significantly lower than the first supply voltage. When operating in response to the first supply voltage, the delay elements exhibit relatively short delays. Conversely, when operating in response to the second supply voltage, the delay elements exhibit relatively long delays.
    Type: Grant
    Filed: November 21, 2003
    Date of Patent: August 29, 2006
    Assignee: Xilinx, Inc.
    Inventors: Bernard J. New, Andrew K. Percey
  • Patent number: 7092293
    Abstract: A configuration circuit includes a latch and a dedicated non-volatile memory cell. The non-volatile memory cell is initially programmed or erased. The latch is then set to store a first logic value by coupling the latch to a first voltage supply terminal in response to an activated control signal. When the control signal is de-activated, the latch is de-coupled from the first voltage supply terminal and coupled to the non-volatile memory cell. If the non-volatile memory cell is programmed, the latch is coupled to a second voltage supply terminal, thereby storing a second logic value in the latch. If the non-volatile memory cell is erased, the latch is isolated from the second voltage supply terminal, and the first logic value remains stored in the latch. The latch can also be directly written through one or more access transistors, thereby facilitating testing.
    Type: Grant
    Filed: November 25, 2003
    Date of Patent: August 15, 2006
    Assignee: Xilinx, Inc.
    Inventors: Phillip A. Young, Sunhom Paak
  • Patent number: 7092273
    Abstract: A p-channel non-volatile memory (NVM) transistor is programmed by shifting the threshold voltage of the transistor. The threshold voltage is shifted by introducing a programming current to the gate electrode of the transistor, and simultaneously introducing a negative bias to the transistor. The threshold voltage of the p-channel NVM transistor is shifted in response to the negative bias condition and the heat generated by the programming current. The high temperature accelerates the threshold voltage shift. The threshold voltage shift is accompanied by an agglomeration of material in the gate electrode. The agglomeration of material in the gate electrode is an indication of the high temperature reached during programming. The threshold voltage shift of the p-channel NVM transistor is permanent.
    Type: Grant
    Filed: February 14, 2006
    Date of Patent: August 15, 2006
    Assignee: Xilinx Inc.
    Inventor: Kevin T. Look
  • Patent number: 7075332
    Abstract: A 6-input LUT architecture includes 64 memory cells, which store 64 corresponding data values. Sixty-four write control circuits are coupled to the 64 memory cells. A first write address decoder receives a first subset of the six input signals, and in response, provides a first set of write select signals to the 64 write control circuits. A second write address decoder receives a second subset of the six input signals and a write clock signal, and in response, provides a plurality of decoded write clock signals to the sixty-four write control circuits. A write data value, which is applied to each of the write control circuits, is written to one of the memory cells in a synchronous manner with respect to the write clock signal in response to the first set of write select signals and the decoded write clock signals.
    Type: Grant
    Filed: June 8, 2004
    Date of Patent: July 11, 2006
    Assignee: Xilinx, Inc.
    Inventors: Steven P. Young, Venu M. Kondapalli, Ramakrishna K. Tanikella
  • Patent number: 7064450
    Abstract: A pad pattern of a die includes first and second sets of elongated pads. The first set of elongated pads is interleaved with the second set of elongated pads. Each of the elongated pads has a bond pad area and a probe pad. Each bond pad area has a first constant width along a substantial portion thereof. Similarly, each probe pad area has a second constant width along a substantial portion thereof. The first constant width is greater than the second constant width. Each elongated pad in the first set has a first orientation. Similarly, each elongated pad in the second set has a second orientation, opposite the first orientation.
    Type: Grant
    Filed: May 11, 2004
    Date of Patent: June 20, 2006
    Assignee: Xilinx, Inc.
    Inventors: Abu K. Eghan, Richard C. Li, Xin X. Wu