Signal Sensitivity Or Transmission Integrity Patents (Class 326/21)
  • Patent number: 7116126
    Abstract: A method of transmitting adjacent signals is disclosed. Sensing is performed on signals in the group and adjacent signals are either switched or delayed if the adjacent signals are switching at the same time. The method is used in networks where coupling and capacitance effects are possible.
    Type: Grant
    Filed: October 16, 2001
    Date of Patent: October 3, 2006
    Assignee: Sun Microsystems, Inc.
    Inventors: Nayon Tomsio, Harsh D. Sharma
  • Patent number: 7099786
    Abstract: A receiving unit may implement voltage compensation using a parameters table, an analog calibration component, and/or a digital calibration component. In certain implementation(s), an integrated circuit may include a voltage driver that modifies a supplied compensated voltage based on a feedback signal. The feedback signal may be produced responsive to a distributed voltage version of the compensated voltage, to a received data signal, and to a comparison involving an expected data value. In other implementation(s), a parameters table may be initialized by storing calibration values in entries in association with respective multiple identifications of multiple external points.
    Type: Grant
    Filed: February 24, 2005
    Date of Patent: August 29, 2006
    Assignee: Rambus Inc.
    Inventors: Huy M. Nguyen, Benedict C. Lau
  • Patent number: 7091741
    Abstract: Provided is an input buffer whose input capacitance presented to input signals can be reduced. The input buffer includes a first differential amplifier which compares the sizes of a first input signal and a second input signal and outputs an output signal as the result of the comparison; a second differential amplifier which compares the sizes of the first input signal and a reference voltage and outputs a second output signal as the result of the comparison; and a third differential amplifier which compares the sizes of the second input signal and the reference voltage and outputs a third output signal as the result of the comparison, wherein the first differential amplifier shares transistors, to which the first and second input signals are input, with the second and third differential amplifiers. The first differential amplifier operates only in a differential operation mode, and the second and third differential amplifiers operate only in a single operation mode.
    Type: Grant
    Filed: September 24, 2004
    Date of Patent: August 15, 2006
    Assignee: Samsung Electronics, Co., Ltd
    Inventor: Kyu-hyoun Kim
  • Patent number: 7088129
    Abstract: A hybrid binary/thermometer code is employed to adjust the output impedance of a variable impedance output driver circuit having an impedance network comprising a plurality of impedance legs each programmably electrically connectable according to the hybrid binary/thermometer code in parallel between a voltage source and the signal pad. The plurality of impedance legs are partitioned into one or more set pairs of binary stepped impedance legs and corresponding thermometer stepped impedance legs. A binary set of calibration signals in the hybrid binary/thermometer code steps a given set of binary stepped impedance legs according to a binary code and a thermometer set of calibration signals in the hybrid binary/thermometer code steps the corresponding set of thermometer stepped impedance legs according to a thermometer code once per full count iteration of the binary set of calibration signals.
    Type: Grant
    Filed: April 30, 2004
    Date of Patent: August 8, 2006
    Assignee: Avago Technologies General IP (Singapore) Pte. Ltd.
    Inventors: Guy Harlan Humphrey, David Lawrence Linam
  • Patent number: 7084662
    Abstract: A variable impedance output driver has been disclosed. One embodiment of the variable impedance output driver includes a first pull-up structure, a pull-down structure, and a comparator, coupled to the first pull-up structure and the pull-down structure, to calibrate the first pull-up structure and the pull-down structure against a reference impedance. Other embodiments are described and claimed.
    Type: Grant
    Filed: February 6, 2004
    Date of Patent: August 1, 2006
    Assignee: Cypress Semiconductor Corporation
    Inventors: Hari Om, Andrew J. Wright
  • Patent number: 7075329
    Abstract: A logic signal isolator comprising a transformer having a primary winding and a secondary winding; a transmitter circuit which drives said primary winding in response to a received logic signal, such that in response to a first type of edge in the logic signal, a signal of a first predetermined type is supplied to the primary winding and in response to a second type of edge in the logic signal, a signal of a second predetermined type is supplied to said primary winding, the primary winding and the transmitter being referenced to a first ground; and the secondary winding being referenced to a second ground which is galvanically isolated from the first ground and said secondary winding supplying to a receiver circuit signals received in correspondence to the signals provided to the primary winding, the receiver reconstructing the received logic signal from the received signals.
    Type: Grant
    Filed: April 29, 2004
    Date of Patent: July 11, 2006
    Assignee: Analog Devices, Inc.
    Inventors: Baoxing Chen, Geoffrey Haigh
  • Patent number: 7071727
    Abstract: A low-pass filter 10 on a microprocessor bus 22 for attenuating radio frequencies from digital signals travelling on the bus 22 from a microprocessor 12 to a peripheral device 20. An RC network is implemented as close as physically possible to the junction of the bus connection to microprocessor 12 and memory 14 to filter radio frequencies to an extent that limits radiation of these frequencies from the length of the bus 22. Wait states are adjusted as necessary to accommodate filtering of the digital signal that is transmitted over microprocessor bus 22.
    Type: Grant
    Filed: February 14, 2003
    Date of Patent: July 4, 2006
    Assignee: Kyocera Wireless Corp.
    Inventor: Robert B. Ganton
  • Patent number: 7053651
    Abstract: A CMOS switching circuit that includes a charge reservoir and a multiplexer connected to the charge reservoir. The multiplexer receives control signals from a delay line and a control signal line, and it delivers a switching signal to an output terminal. A first set of signals delivered to the control terminals of the multiplexer causes the charge reservoir to deliver charge to the output terminal, and a second set of signals delivered to the control terminals causes charging of the charge reservoir. With the charge reservoir, charge from falling signals is conserved and used to help rising signals at the output, reducing the power required to provide an output switching signal.
    Type: Grant
    Filed: September 15, 2004
    Date of Patent: May 30, 2006
    Assignee: Avago Technologies General IP Pte. Ltd.
    Inventor: Jason Gonzalez
  • Patent number: 7038486
    Abstract: A plurality of sets of circuits are provided, each of which generates an impedance code through the use of an impedance control circuit in association with a resistive element connected to an external terminal, and each of which varies the impedance in accordance with such an impedance code. The impedance control circuit includes an impedance comparator which is formed equivalently to the resistive element and the plurality of sets of circuits, and which performs an impedance comparison with each of a plurality of replica circuits to form an up signal that increases the impedance and a down signal that decreases the impedance. Counters are provided adjacent to the individuals of the plurality of sets of circuits to thereby generate the impedance codes in response to the up signal and the down signal.
    Type: Grant
    Filed: July 13, 2004
    Date of Patent: May 2, 2006
    Assignee: Renesas Technology Corp.
    Inventors: Satoshi Aoyama, Atsuhiro Hayashi, Yasuhiko Takahashi
  • Patent number: 7034566
    Abstract: Aspects for increased noise immunity for clocking signals in high speed digital systems are described. The aspects include buffering a differential clock signal with a single buffer circuit for a plurality of load circuits and configuring the single buffer circuit to adjust to alterations in the number of load circuits receiving the differential clock signal. The configuring achieves a constant bandwidth and voltage level for the clock signal output while adjusting to alterations in the number of load circuits.
    Type: Grant
    Filed: February 12, 2004
    Date of Patent: April 25, 2006
    Assignee: International Business Machines Corporation
    Inventors: Hayden C. Cranford, Jr., Joseph M. Stevens
  • Patent number: 7024496
    Abstract: An I/O pad has a data transmitting circuit, a data monitoring control circuit, and a control selection circuit. The control selection circuit controls the data transmitting circuit. When it is enabled, data in the data transmitting circuit are exported to a receiving circuit. When it is disabled, data exportation stops. The data monitoring circuit receives signals of the data transmission circuit and export signals to the control selection circuit. The data monitoring circuit judges whether the data transmission is under a stable condition. If it is not, an unstable signal is exported to a first input end of the control selection circuit. A second input end of the control selection circuit receives an output enabling signal. When the data transmission is stable and the output enabling signal indicates a disable status, the control selection circuit disables the data transmitting circuit. Otherwise, the control selection circuit enables the data transmitting circuit.
    Type: Grant
    Filed: August 30, 2004
    Date of Patent: April 4, 2006
    Assignee: VIA Technologies, Inc.
    Inventor: Nai-Shung Chang
  • Patent number: 7023236
    Abstract: A data transmission system capable of transmitting data at high speed without being bound by a counterpart's power supply voltage can be realized. The data transmission system comprises multiple electronic equipment having individual power supplies, a cable for connecting between the multiple electronic equipment so as to transmit signals therebetween, digital data transmitting circuits extending, between the multiple electronic equipment and the cable and each having an open drain type output section at the transmitting end, and an input section provided with a pull-up type resistor at the receiving end, wherein the resistor and the output section are moved from the electronic equipment to the connector of the cable so that parasitic capacitance for restricting time constant of waveforms of signals when rising is changed from a capacitance to a small capacitance.
    Type: Grant
    Filed: November 19, 2002
    Date of Patent: April 4, 2006
    Assignee: Rohm Co., Ltd.
    Inventor: Isao Yamamoto
  • Patent number: 7023237
    Abstract: Power dissipation of a semiconductor integrated circuit chip is reduced when it is operated at an operating voltage of 2.5 V or below. A switching element is provided in each circuit block within the chip. Constants of the switching element are set so that leakage current in each switching element in their off-state is smaller than the subthreshold current of MOS transistors within the corresponding circuit block. Active current is supplied to active circuit blocks, while switching elements of non-active circuit blocks are turned off. Thus, dissipation currents of non-active circuit blocks are limited to leakage current value of corresponding switching elements. Thus, the sum of dissipation currents of non-active circuit blocks is made smaller than the active current in the active circuit blocks. As a result, power dissipation in the semiconductor integrated circuit chip can be reduced even in the active state.
    Type: Grant
    Filed: December 7, 2004
    Date of Patent: April 4, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Takeshi Sakata, Kiyoo Itoh, Masashi Horiguchi
  • Patent number: 7009420
    Abstract: An input circuit for receiving a signal at an input on an integrated circuit, particularly a DRAM circuit, and for assessing the signal with respect to a reference voltage is provided. One embodiment provides a termination circuit for setting a termination voltage, wherein the termination circuit includes a first resistor and a second resistor connected in series between a high voltage potential and a low voltage potential, the termination voltage being tapped between the first and second resistors, a first voltage-dependent resistor element having a first resistance gradient connected in parallel with the first resistor and a second voltage-dependent resistor element having a second resistance gradient connected in parallel with the second resistor, wherein the resistance values of the first and second resistor elements are controlled by a control voltage to set the termination voltage.
    Type: Grant
    Filed: April 1, 2004
    Date of Patent: March 7, 2006
    Assignee: Infineon Technologies AG
    Inventor: Andre Schäfer
  • Patent number: 7005893
    Abstract: High performance clock-powered logic runs at below supply levels and reduces the need for faster digital logic circuitry. In a preferred embodiment, a clocked buffer (101) is used to drive the signal line. The receiving end of the line is connected to a jam latch (123), preferably followed by an n-latch (125), followed by the digital logic (109), and followed by a second n-latch (127). The first n-latch is eliminated in an alternative embodiment, preferably one that uses complementary data signals.
    Type: Grant
    Filed: July 18, 2000
    Date of Patent: February 28, 2006
    Assignee: University of Southern California
    Inventors: William C. Athas, Nestor Tzartzanis, Weihua Mao, Lena Peterson
  • Patent number: 7003602
    Abstract: In apparatuses (1, 2, 3) controlled or operated via an I2 C bus, it may be necessary to take measures to suppress interference signals at the data signal input/output of the respective apparatus without impairing the data transport at the same time. The data line at the data signal input/output contains an RC element, in the form of a low-pass filter, with a diode connected in parallel with the RC element, the low-pass filter action allowing the arrangement to be used to suppress interference signals acting on the data signal input/output, and, secondly, the transmissive action of the diode meaning that the arrangement does not impair a data signal leaving the data signal input/output.
    Type: Grant
    Filed: November 19, 2001
    Date of Patent: February 21, 2006
    Assignee: Thomson Licensing
    Inventors: Alfred Selz, Veit Armbruster
  • Patent number: 6995585
    Abstract: A self-timed data transmission system includes a data bit group defined by at least two data bits to be transmitted from a corresponding plurality of transmitting storage elements. A corresponding plurality of data receiving storage elements receives the data transmitted from said transmitting storage elements. Encoding logic is used for encoding the transmitted data from the transmitting storage elements, wherein the encoded transmitted data is coupled to a plurality of data lines. The encoding logic is further configured so as to result in only one of the plurality of data lines being activated during a given data transmission cycle.
    Type: Grant
    Filed: August 5, 2003
    Date of Patent: February 7, 2006
    Assignee: International Business Machines Corporation
    Inventors: Darren L. Anand, John E. Barth, Jr.
  • Patent number: 6992507
    Abstract: A method for selecting an I/O buffer. The method includes providing a plurality of I/O buffers. Each one of the plurality of I/O buffers has a different performance characteristic. Each one of the plurality of I/O buffers is coupled to a receiving device through a corresponding one of a plurality of transmission lines. Each one of the plurality of buffers is driven by a logic signal. Each one of the transmission lines produces a corresponding series of output logic signals. The plurality of output signals is observed. The method includes selecting one of the plurality of I/O buffers in accordance with the observed output signals.
    Type: Grant
    Filed: March 30, 2004
    Date of Patent: January 31, 2006
    Assignee: EMC Corporation
    Inventor: Tomer Jackman
  • Patent number: 6989686
    Abstract: The present invention is to provide a logic circuit which assures short-circuit current reduction by using a gate which uniquely fixes the level of each node and also reduces leakage current so that the power is turned on and off quickly. Logic gates of the subject logic circuit are divided into first-type logic gate and second-type logic gates. The first-type logic gate outputs high potential under the specific status and the second-type logic gate outputs low potential under the specific status. Under the state that the high potential is supplied to the first-type logic gates and the low potential is supplied to the second-type logic gates, the power switch MOS is turned on. Further, in case of the adder, the specific status is equal to selecting a constant as an input of the adder. For general logic circuit, specific flip-flops are introduced to implement this specific status.
    Type: Grant
    Filed: October 15, 2004
    Date of Patent: January 24, 2006
    Assignee: Renesas Technology Corp.
    Inventor: Fumio Arakawa
  • Patent number: 6985004
    Abstract: An electrical wiring structure and method of designing thereof. The method identifies at least one wire pair having a first wire and a second wire. The second wire is already tri-stated or can be tri-stated. The wire pair may have a same-direction switching probability per clock cycle that is no less than a predetermined or user-selected minimum same-direction switching probability. Alternatively, the wire pair may have an opposite-direction switching probability per clock cycle that is no less than a predetermined or user-selected minimum opposite-direction switching probability. The first wire and the second wire satisfy at least one mathematical relationship involving: a spacing between the first wire and the second wire; and a common run length of the first wire and the second wire.
    Type: Grant
    Filed: February 12, 2001
    Date of Patent: January 10, 2006
    Assignee: International Business Machines Corporation
    Inventors: John M. Cohn, Alvar A. Dean, Amir H. Farrahi, David J. Hathaway, Thomas M. Lepsic, Jagannathan Narasimhan, Scott A. Tetreault, Sebastian T. Ventrone
  • Patent number: 6985005
    Abstract: An output amplifier is provided for use in a bidirectional communications interface, for example, connecting a transmitter and a receiver to a transmission line. The output amplifier includes a differential amplifier pair connected to output circuitry. The differential amplifier pair receives differential data signal pairs from each of a transmission line and a transmitter. The output circuitry receives signals from the differential amplifier pair and, in response, forms single-ended output logic signals. The output amplifier suppresses electronic input noise throughput using an asymmetric transfer characteristic that offsets output signal logic levels with respect to input noise signal levels. The asymmetric transfer characteristic is produced by skewing a transfer characteristic of the differential amplifier pair using an asymmetrical transistor configuration at an output side of the differential amplifier pair.
    Type: Grant
    Filed: November 20, 2001
    Date of Patent: January 10, 2006
    Assignee: Silicon Image
    Inventors: Gyudong Kim, Min-Kyu Kim
  • Patent number: 6980021
    Abstract: An output buffer for driving a capacitively-terminated transmission line produces a waveform which comprises a first portion during which the waveform transitions from a voltage V1 to a voltage V2; a second portion during which it remains fixed at V2; a third portion during which it transitions to a voltage V3; and a fourth portion during which it remains fixed at V3. The waveform is created within a unit interval whenever successive data bits transition between logic states. The first and second portions are generated with circuitry arranged such that V2 is maximized by reducing the buffer's output impedance. The fourth portion is generated with circuitry which has a non-zero output impedance preferably equal to the transmission line's characteristic impedance, to absorb transitions reflected back to the source circuitry by the capacitive termination.
    Type: Grant
    Filed: June 18, 2004
    Date of Patent: December 27, 2005
    Assignee: Inphi Corporation
    Inventors: Nikhil K. Srivastava, Gopal Raghavan, Carl W. Pobanz
  • Patent number: 6978434
    Abstract: A wiring structure of a semiconductor device, includes a wiring layer formed on an insulating film, a width (W) of each wire in the wiring layer and a thickness (H) of the insulating film satisfying “W/H<1” a length (L) of each wiring in the wiring layer being equal to or longer than 1 mm.
    Type: Grant
    Filed: June 23, 2000
    Date of Patent: December 20, 2005
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Naoyuki Shigyo, Tetsuya Yamaguchi
  • Patent number: 6972597
    Abstract: Method and apparatus for use with simultaneous bi-directional (SBD) input/output circuits are included among the embodiments. In exemplary systems, the receiver in an SBD circuit compares a bit line voltage to two different voltages representing the two voltages that are expected on the bit line, based on the data that the driver in the SBD circuit is currently driving. Other embodiments are described and claimed.
    Type: Grant
    Filed: December 29, 2003
    Date of Patent: December 6, 2005
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Woo-Seop Kim
  • Patent number: 6970010
    Abstract: A method is described that involves driving a first current through a line and a termination resistance so that a logical value on the line changes from a first logical value to a second logical value. The method also includes holding the second logical value on the line by driving a second current through the line and the termination resistance where the second current less than the first current. An apparatus is described that includes a driver that drives a first current through a line and a termination resistance so that a logical value on the line changes from a first logical value to a second logical value. The driver holds the second logical value on the line by driving a second current through the line and the termination resistance. The second current is less than said first current.
    Type: Grant
    Filed: August 18, 2003
    Date of Patent: November 29, 2005
    Assignee: Intel Corporation
    Inventors: Jeffrey R. Wilcox, Noam Yosef, Marcelo Yuffe
  • Patent number: 6961229
    Abstract: An electronic circuit device having a power-supply structure capable of supporting fast signals in and above a GHz band is offered. A driver transistor is formed in a surface of a semiconductor substrate. Power-supply/ground pair transmission lines which provide the driver transistor with power and signal/ground pair transmission lines which transmit signals to a receiver are formed on the semiconductor substrate. The power-supply/ground pair transmission lines are connected to a drain layer of the driver transistor and a P+ layer in a P well. The signal/ground pair transmission lines are connected to a source layer of the driver transistor and a P+ layer in the P well.
    Type: Grant
    Filed: February 20, 2004
    Date of Patent: November 1, 2005
    Assignees: Sanyo Electric Co., Ltd., Oki Electric Industry Co., Ltd., Sharp Kabushiki Kaisha, Sony Corporation, Kabushiki Kaisha Toshiba, NEC Corporation, Hitachi, Ltd., Matsushita Electric Industrial Co., Ltd., Mitsubishi Denki Kabushiki Kaisha, Fujitsu Limited, Rohm Co., Ltd.
    Inventors: Kanji Otsuka, Tamotsu Usami
  • Patent number: 6943588
    Abstract: Systems and methods are provided using dynamically adjustable differential output drivers. Integrated circuits such as programmable logic devices may be provided with adjustable differential output drivers for transmitting high-speed data to other integrated circuits. The peak-to-peak output voltage and common-mode voltage of the output drivers may be adjusted. Dynamic control circuitry may be used to control the settings of current sources, programmable resistors, and voltage source circuitry in the adjustable differential output driver automatically in real time. The adjustable components in the differential output driver may be adjusted by the dynamic control circuitry based on feedback information received from the integrated circuit to which the data is transmitted.
    Type: Grant
    Filed: September 24, 2003
    Date of Patent: September 13, 2005
    Assignee: Altera Corporation
    Inventors: Mei Luo, Sergey Shumarayev, Wilson Wong, Chong H. Lee
  • Patent number: 6933745
    Abstract: A system and method for transmitting data includes one or more transmitters connected to each of at least one bus data line via open-driver bus data line drivers, and one or more receivers. In a preferred embodiment, the devices are interconnected by a parallel interface using a bus architecture having the bus data and carrier-sense (CRS) lines each driven by open-collector or open-drain drivers in a wired-and configuration. Pullup resistors and a common clock signal are also provided. Each device is provided with an interfacing unit which connects the device to the bus, and detects collisions by comparing data transmitted by the device with data received from the bus. The invention is particularly applicable to implementation as a backplane connecting intercommunicating printed wiring boards having interfaces such as the IEEE 802.3 (Ethernet) Media Independent Interface (MII), the interfacing unit serving to emulate the Ethernet PHY.
    Type: Grant
    Filed: August 28, 2003
    Date of Patent: August 23, 2005
    Assignee: Spediant Systems Ltd.
    Inventors: Eliezer Magal, Zeev Oster
  • Patent number: 6930507
    Abstract: A termination network has multiple resistors forming multiple voltage dividers with a common node. Half of the resistors are coupled to the positive power supply voltage with P channel field effect transistors (PFETs) and the other half are coupled to the negative or ground power supply voltage with N channel FETs (NFETs). Logic signals are used to control the gates of the FETs. By modifying which FETs are ON, the termination network can be selectively controlled to produce various offset levels with the same impedance level. The impedance levels may also be modified while maintaining the same offset level. A delay circuit may be selectively employed to feedback control signals after a selected delay time to adjust the threshold level to dynamically or statically optimize signal reception.
    Type: Grant
    Filed: July 10, 2003
    Date of Patent: August 16, 2005
    Assignee: International Business Machines Corporation
    Inventors: Daniel M. Dreps, Frank D. Ferraiolo, Anand Haridass, Bao Gia-Harvey Truong
  • Patent number: 6917217
    Abstract: There is provided an apparatus for generating an input signal for a cable that is mismatched on an output side. The apparatus has a line driver for connecting to an input of the cable via a resistor. The line driver includes a controller that, depending on a data input signal, is for triggering (a) a first switch to apply a supply voltage at an input of the resistor, (b) a second switch to apply a reference potential at the input of the resistor, and (c) a third switch to apply an auxiliary voltage at the input of the cable, all of them at predeterminable points in time, in order to minimize power dissipation in the resistor.
    Type: Grant
    Filed: July 31, 2003
    Date of Patent: July 12, 2005
    Assignee: IC-Haus GmbH
    Inventor: Manfred Herz
  • Patent number: 6917546
    Abstract: In a memory device which is used with the memory device connected to a data bus, the memory device includes an active termination circuit for terminating the memory device when the active termination circuit is electrically put into an active state and for unterminating the memory device when the active termination circuit is electrically put into an inactive state. The memory device further includes a control circuit for controlling the active termination circuit to electrically put the active termination circuit into the active state or the inactive state.
    Type: Grant
    Filed: August 23, 2002
    Date of Patent: July 12, 2005
    Assignee: Elpida Memory, Inc.
    Inventor: Yoshinori Matsui
  • Patent number: 6906549
    Abstract: In some embodiments, a chip includes first and second nodes, a variable voltage source, and transmitter and control circuitry. The transmitter includes a driver coupled to the first and second nodes, and first and second resistive structures coupled between the first and second nodes, respectively, and the variable voltage source. The control circuitry selects an impedance level for the first and second resistive structures, and detect coupling of a remote receiver to the transmitter through interconnects and detect decoupling of the remote receiver from the transmitter. Other embodiments are described and claimed.
    Type: Grant
    Filed: December 31, 2002
    Date of Patent: June 14, 2005
    Assignee: Intel Corporation
    Inventors: Theodore Zale Schoenborn, Andrew Martwick
  • Patent number: 6903578
    Abstract: A logic isolation circuit has a transmitter circuit for receiving a logic input signal and providing a periodic signal to an isolation barrier, and a receiving circuit for receiving the periodic signal from the isolation barrier and for providing an output signal that indicates the transitions in the logical input signal.
    Type: Grant
    Filed: May 11, 2004
    Date of Patent: June 7, 2005
    Assignee: Analog Devices, Inc.
    Inventors: Geoffrey T. Haigh, Baoxing Chen
  • Patent number: 6888369
    Abstract: The circuits and methods are provided for impedance termination on an integrated circuit. A network of resistors are formed on an integrated circuit (IC) to provide on-chip impedance termination to differential input/output (IO) pins. Transistors are coupled in the network of termination resistors. The transistors provide additional termination impedance to the differential IO pins. The transistors can be turned ON or OFF separately to change the impedance termination.
    Type: Grant
    Filed: July 17, 2003
    Date of Patent: May 3, 2005
    Assignee: Altera Corporation
    Inventors: Bonnie I. Wang, Chiakang Sung, Khai Nguyen
  • Patent number: 6888370
    Abstract: The on-chip impedance termination circuits can be dynamically adjusted to match transmission line impedance values. A network of termination resistors on an integrated circuit provides termination impedance to a transmission line coupled to an IO pin. The termination resistors are coupled in series and in parallel with each other. Pass gates are coupled to the resistors. The pass gates are individually turned ON or OFF to couple or decouple resistors from the transmission line. Each pass gate is set to be ON or OFF to provide a selected termination resistance value to the transmission line. The termination resistance of the resistor network can be increased or decreased to match the impedance of different transmission lines. The termination resistance can also be varied to compensate for changes in the resistors caused by temperature variations on the integrated circuit or other factors.
    Type: Grant
    Filed: August 20, 2003
    Date of Patent: May 3, 2005
    Assignee: Altera Corporation
    Inventors: Mei Luo, Wilson Wong, Sergey Shumarayev
  • Patent number: 6886065
    Abstract: Over-terminating the differential mode impedance of a differential transmission line, such as an INFINIBAND™ cable, at the receiving end, improves the differential signal integrity for typical variations in termination network impedance component (e.g., resistor) and transmission line characteristics. Eye opening of the differential signal can be made larger with reduced attenuation but increased jitter compared to under-terminating the differential mode impedance. Because the differential signal quality (larger eye opening) is improved, data can be transmitted over a longer transmission line with the same transmitter and receiver.
    Type: Grant
    Filed: September 29, 2001
    Date of Patent: April 26, 2005
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Chi Kim Sides, Sompong Paul Olarig
  • Patent number: 6876223
    Abstract: EMI caused on a sensitive pin by large electric current flowing through a load pin when driving a high load is reduced or substantially eliminated. An equal amount of current, but in opposite direction, is caused to be flown in another pin (“third pin”) located close to the load pin. As a result, the EMI caused by the third pin cancels the EMI generated by the load pin. During a discharge phase, a fourth pin carries and equal amount of current, but in opposite direction, to that in the load pin. The third and fourth pins may be formed by power supply pin and ground pin. A control path may avoid a path from the third pin to the fourth pin during both the charging and discharging phases. In addition, the high load may be driven by a programmable driver which uses an amount of current proportionate to the extent of load, thereby avoiding parasitic currents. EMI is further reduced as a result.
    Type: Grant
    Filed: July 25, 2002
    Date of Patent: April 5, 2005
    Assignee: Texas Instruments Incorporated
    Inventors: Gireesh Rajendran, Anil Kumar, Debapriya Sahu, Srinivasan Venkatraman
  • Patent number: 6876224
    Abstract: A method of enhancing noise margin on digital signal lines of a system includes steps of evaluating impedances and lengths of the digital signal lines. Resonances of each digital signal line are determined, and target waveforms for each digital signal line optimized for noise margin are determined. A configuration is generated for a programmable device driver to configure the device driver to generate the waveform optimized for noise margin. An alternative embodiment selects waveforms, and corresponding configurations, from a group of possible waveforms at boot time to ensure that data is transferred with optimum noise margins. Also claimed is apparatus embodying bus drivers capable of driving a bus with a waveform approximating blended trapezoidal and sinusoidal edge shapes, this waveform being optimum for noise margin in certain systems having multidrop busses.
    Type: Grant
    Filed: November 5, 2002
    Date of Patent: April 5, 2005
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: David John Marshall, Philip L. Barnes, Larry Jay Thayer
  • Patent number: 6873660
    Abstract: A data transmitter for converting single-ended data to differential data has the advantages of energy saving, being able to precisely control the common-mode level, and being wide in operational frequency width. An NMOS transistor is employed as a source follower to provide current flowing to conduction paths, and a PMOS transistor is also employed as another source follower to discharge the current of the conduction paths.
    Type: Grant
    Filed: May 3, 2001
    Date of Patent: March 29, 2005
    Assignee: Himax Technologies, Inc.
    Inventor: Lin-kai Bu
  • Patent number: 6873178
    Abstract: Circuits and methods for driving buses (data buses or address buses) which provide a reduction in interference such as crosstalk between adjacent bus lines of a bus, even as the width of the bus increases and the intervals between the bus lines decrease. In the bus driving circuits and methods, a portion of the bus lines are driven at a first time, and a portion of the bus lines are driven at a second time, subsequent to the first time, so as to reduce or eliminate crosstalk between adjacent bus lines.
    Type: Grant
    Filed: January 29, 2003
    Date of Patent: March 29, 2005
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Hoi-Jin Lee
  • Patent number: 6870390
    Abstract: A transmit line driver with selectable slew rates and a common mode idle state comprises a capacitor array of selectable capacitors coupled between a line driver and a pre-driver wherein a slew rate may be selected by the selectable capacitors. A common mode idle state is provided by coupling a selectable switch (MOSFET in the described embodiment) to a mirror device that provides a bias current to the pre-driver wherein, when the bias current is removed by the switch, the pre-driver produces an output signal that is equal to the supply voltage for the circuit. Accordingly, a differential pair of the line driver are both biased on and provide a common mode idle state. The common mode idle state is equal to one half of an output signal magnitude for a logic one.
    Type: Grant
    Filed: September 11, 2003
    Date of Patent: March 22, 2005
    Assignee: Xilinx, Inc.
    Inventors: Eric D. Groen, Charles W. Boecker, William C. Black
  • Patent number: 6864707
    Abstract: Input structures and topologies are provided for coupling a differential input into a first stage of a circuit, topology, or device. An input pin is coupled to an impedance divider that translates an input voltage to accommodate low input voltage levels, while not saturating an input differential pair. A termination pair with a center tap pin is further coupled to the input pins. The center tap facilitates coupling different termination configurations to the input signal. The topologies accommodate packaged devices that have at least three external pins, two pins for the coupling of a differential input signal, and a pin for the termination pair center tap.
    Type: Grant
    Filed: September 30, 2002
    Date of Patent: March 8, 2005
    Assignee: Micrel, Incorporated
    Inventors: Thomas S. Wong, Stephen J. B. Pratt
  • Patent number: 6856165
    Abstract: In a circuit arrangement for adapting the characteristic wave impedance at line ends of a vehicle data bus having at least two data bus lines and data terminals, each with a transceiver unit for differential-mode signal transmission on the data bus, the data bus is connected to the transceiver unit via a connection interface that includes a reactor for filtering interference on the data bus and an adaptation resistor network for adapting the characteristic wave impedance of a data bus line. The adaptation resistor network is arranged between the reactors and the respective line ends of the data bus lines, while the adaptation resistor network connects the line ends to ground via a capacitor.
    Type: Grant
    Filed: July 31, 2003
    Date of Patent: February 15, 2005
    Assignee: DaimlerChrysler AG
    Inventor: Bernhard Rall
  • Patent number: 6853218
    Abstract: An apparatus comprising a first arbiter cell, a second arbiter cell and a selection device. The first arbiter cell may be configured to lock if one or more requests are not resolved within a first predetermined time period. The second arbiter cell may be configured to dominate if the first arbiter cell enters a metastable state. The selection device may be configured to provide arbitration between the first and second arbiter cells within a second predetermined time period.
    Type: Grant
    Filed: December 19, 2003
    Date of Patent: February 8, 2005
    Assignee: Cypress Semiconductor Corp.
    Inventor: Grahame K. Reynolds
  • Patent number: 6853213
    Abstract: Disclosed is an input/output circuit having a terminating circuit that contributes to a smaller chip area. The input/output includes an output buffer having a first series circuit, which comprises a first transistor and a resistor and a second series circuit, which comprises a second transistor and a resistor, connected in parallel between a high-potential power supply and an input/output pin, as well as a third series circuit, which comprises a third transistor and a resistor and a fourth series circuit, which comprises a fourth transistor and a resistor, connected in parallel between the input/output pin and a low-potential power supply.
    Type: Grant
    Filed: October 25, 2002
    Date of Patent: February 8, 2005
    Assignee: Elpida Memory, Inc.
    Inventor: Seiji Funaba
  • Patent number: 6850089
    Abstract: A capacitor-coupling acceleration apparatus is an accelerating circuit capable of being applied to interconnect lines in an integrated circuit in order to reduce delay owing to parasitic resistance and capacitance of the interconnect lines in the integrated circuit. The apparatus can be disposed between the interconnect lines. When a signal transmitted on the interconnect line has a change from a low-level voltage to a high-level voltage, the apparatus detects the voltage level change of the signal and provides a charging loop to charge the interconnect line, thereby accelerating the change from the low-level voltage to the high-level voltage. When a signal on the interconnect line has a change from the high-level voltage to the low-level voltage, the apparatus detects the voltage level change of the signal and provides a discharging loop to discharge the interconnect line, thereby accelerating the change from the high-level voltage to the low-level voltage.
    Type: Grant
    Filed: January 13, 2003
    Date of Patent: February 1, 2005
    Assignee: Industrial Technology Research Institute
    Inventors: Hong-Yi Huang, Shih-Lun Chen
  • Patent number: 6844754
    Abstract: In a memory system having a data bus transferring data in either direction, highly reliable data transfer is provided regardless of the direction in which data is transferred. The signal lines of a data bus (12) bidirectionally transfer data. That is to say, during data write operations to a DIMM, the signal lines transfer data from a memory controller (10) to the DIMM, and during data read operations, they transfer data from the DIMM to the memory controller (10). The signal lines have, as terminating resistors, terminating variable resistors (VRt) whose impedance is controlled by the memory controller (10). During data write operations to the DIMM, the memory controller (10) sets the impedance of each terminating variable resistor (VRt) at a value suitable for writing, and during data read operations, it sets the impedance of each terminating variable resistor (VRt) at a value suitable for reading.
    Type: Grant
    Filed: November 20, 2002
    Date of Patent: January 18, 2005
    Assignee: Renesas Technology Corp.
    Inventor: Tadato Yamagata
  • Patent number: 6838900
    Abstract: A bus architecture for the application of data transmission between distinct integrated circuits. The bus architecture includes at least one transmission line connecting with I/O pin of ICs for transmitting data. In a middle point of the transmission line, there is a middle resistor with a resistance value preferably equal to the characteristic impedance of the transmission line. In addition, there are internal pull-up resistors within the ICs, which has a first end coupled to the I/O pin and a second end coupled to the voltage source. Each pull-up resistor has a resistance value higher than the characteristic impedance of the transmission line, for example, 2 or 3 times of the characteristic impedance, for suppressing the rising edge ringback.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: January 4, 2005
    Assignee: VIA Technologies, Inc.
    Inventors: Jin-Cheng Huang, Ching Fu Chuang
  • Patent number: 6826635
    Abstract: An I/O pad has a data transmitting circuit, a data monitoring control circuit, and a control selection circuit. The control selection circuit controls the data transmitting circuit at the control end, so as to enable or disable the transmission. When it is enabled, data in the data transmitting circuit are exported to a receiving circuit. When it is disabled, data exportation stops. The data monitoring circuit receives signals of the data transmission circuit and export signals to the control selection circuit. The data monitoring circuit judges whether the data transmission is under a stable condition. If it is not yet, an unstable signal is exported to a first input end of the control selection circuit. A second input end of the control selection circuit receives an output enabling signal. The output end of the control selection circuit is connected to the control end of the data transmitting circuit.
    Type: Grant
    Filed: September 7, 2001
    Date of Patent: November 30, 2004
    Assignee: VIA Technologies, Inc.
    Inventor: Nai-Shung Chang
  • Patent number: 6822476
    Abstract: The present invention is to provide a logic circuit which assures short-circuit current reduction by using a gate which uniquely fixes the level of each node and also reduces leakage current so that the power is turned on and off quickly. Logic gates of the subject logic circuit are divided into first-type logic gate and second-type logic gates. The first-type logic gate outputs high potential under the specific status and the second-type logic gate outputs low potential under the specific status. Under the state that the high potential is supplied to the first-type logic gates and the low potential is supplied to the second-type logic gates, the power switch MOS is turned on. Further, in case of the adder, the specific status is equal to selecting a constant as an input of the adder. For general logic circuit, specific flip-flops are introduced to implement this specific status.
    Type: Grant
    Filed: January 21, 2003
    Date of Patent: November 23, 2004
    Assignee: Renesas Technology Corporation
    Inventor: Fumio Arakawa