Signal Sensitivity Or Transmission Integrity Patents (Class 326/21)
  • Patent number: 5828233
    Abstract: A mixed-mode, overvoltage tolerant input buffer for interfacing to a tristate bus line is disclosed, the input buffer having a bus hold feature for maintaining the state of the input buffer output and bus line when the bus line enters into the tristate mode, the input buffer being capable of suppressing leakage currents from the bus input through the bus hold circuit to the input buffer power supply during overvoltage conditions. The bus hold circuit has a feedback inverter coupled between the output and the bus input for providing a stabilizing feedback signal to the bus input, the inverter being powered by a source voltage which is selectively coupled to the input buffer power supply, the source voltage being isolated from the input buffer power supply during overvoltage conditions.
    Type: Grant
    Filed: September 12, 1996
    Date of Patent: October 27, 1998
    Assignee: Quality Semiconductor, Inc.
    Inventors: Hung T. Nguyen, Leo Lee
  • Patent number: 5818263
    Abstract: An improved local clock driver for locating race conditions within a integrated digital circuit. Highly integrated digital circuits have many local circuits and each local circuit has a local clock driver. The local clock driver strengthens and distributes a clock signal within the local circuit. The improved local clock driver introduces a controllable delay circuit in all the local clock drivers of the digital integrated circuit. By selectively delaying each local clock driver, clock skew problems that cause race conditions can be located. To compensate for such race conditions caused by clock skew problems, the delay circuit can be turned on in the receiving local block circuit.
    Type: Grant
    Filed: September 29, 1995
    Date of Patent: October 6, 1998
    Assignee: Intel Corporation
    Inventor: Roni Ashuri
  • Patent number: 5818260
    Abstract: A driver for providing binary signals from a data system to a transmission line includes a data input node and an output transistor coupled between a data output node and ground. The output transistor has a gate, a source and a corresponding gate-source voltage therebetween. A first transistor is coupled to the gate of the output transistor and is responsive to signals applied to the input node. It conducts a discharge current from the gate of the output transistor for discharging the gate of the output transistor to reduce its gate-source voltage. A clamping circuit clamps the gate-source voltage of the output transistor to a first voltage level above ground to prevent the discharge current from reducing the, gate-source voltage of the output transistor to ground.
    Type: Grant
    Filed: April 24, 1996
    Date of Patent: October 6, 1998
    Assignee: National Semiconductor Corporation
    Inventor: James R. Kuo
  • Patent number: 5815031
    Abstract: An improved signal line routing scheme includes a plurality of dynamic signal lines disposed in parallel to each other, and a plurality of static signal lines disposed in parallel to each other and also disposed in parallel with the plurality of dynamic signal lines, wherein at least one of the plurality of static signal lines is disposed immediately adjacent to each one of the plurality of dynamic signal lines.
    Type: Grant
    Filed: June 19, 1997
    Date of Patent: September 29, 1998
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Teik-Chung Tan, Stephen C. Kromer, Joe Peters
  • Patent number: 5808483
    Abstract: A logic circuit combines a plurality of pass-transistor logic trees and a multiple-input logic gate for receiving intermediate logic signals from the respective pass-transistor logic trees, and can express a complex logical operation while decreasing the number of stages in pass-transistor logic trees and improving operation speed. Even a logical operation that cannot be expressed efficiently by a known or conventional pass-transistor logic circuit can be expressed efficiently with performance higher than that of a known CMOS logic circuit. Furthermore, when a static feedthrough current of the multiple-input logic gate is suppressed, power consumption can be reduced. In some embodiments, since circuitry for suppressing a static feedthrough current of the multiple-input logic gate is arranged so that a probability of occurrence of logical collision with a preceding stage will decrease or will be nil, power consumption can further be reduced.
    Type: Grant
    Filed: September 20, 1996
    Date of Patent: September 15, 1998
    Assignee: Kawasaki Steel Corporation
    Inventor: Norimitsu Sako
  • Patent number: 5796270
    Abstract: A driver circuit provides for selectively changing the state of an output signal, such as a pre-charged dynamic bus signal. The circuit detects whether or not the data is the opposite state as the pre-charged bus signal, and if so, it drives the bus to the appropriate state. The output from the circuit is self-timed when data can be driven onto the bus as soon as data is valid, i.e., data propagates from the input of the circuit to the bus without depending on a clock or other timing edge.
    Type: Grant
    Filed: August 22, 1996
    Date of Patent: August 18, 1998
    Assignee: International Business Machines Corporation
    Inventors: John Atkinson Fifield, Glenn Peter Giacalone, Peter Joel Jenkins
  • Patent number: 5789936
    Abstract: A circuit for sensing a communication state equipped with a signal detecting circuit and a busy signal generating circuit for sensing different communication states accurately monitors the communication state of a communication network. The circuit includes a signal detecting section for detecting a start signal representing the initiation of data transmission and a stop signal informing of the finish of the data transmission from serial data and serial clock received via a bus, a busy signal generating section for determining a level of a busy signal according to levels of the start signal and stop signal of the signal detecting section, and a microprocessor for controlling the transmission/reception of the serial data and serial clock in accordance with the level of the busy signal of the busy signal generating section. Thus, when data is transmitted to other auxiliary device except the auxiliary devices under being communicated, the destroy of the communicating data is prevented.
    Type: Grant
    Filed: August 26, 1996
    Date of Patent: August 4, 1998
    Assignee: Daewoo Electronics Co., Ltd.
    Inventor: Young-Min Kim
  • Patent number: 5789944
    Abstract: An asynchronous anticontention circuit for a bi-directional bus. The asynchronous anticontention circuit comprises an anticontention circuit coupled to an asynchronous delay circuit. The anticontention circuit receives a driver select signal and generates a first signal and a second signal. The first signal and the second signal each have an active state and an inactive state. When the driver select signal is in a first logic state, the first signal is in the inactive state and the second signal is in the active state. When the driver select signal transitions from the first logic state to a second logic state, the anticontention circuit transitions the second signal from the active state to the inactive state. The asynchronous delay circuit couples the transition of the second signal to the anticontention circuit after a delay of time. After the delay of time, the anticontention circuit transitions the first signal from the inactive state to the active state.
    Type: Grant
    Filed: June 28, 1996
    Date of Patent: August 4, 1998
    Assignee: Cypress Semiconductor Corp.
    Inventors: Garrett Choy, W. Alfred Graf, III
  • Patent number: 5789945
    Abstract: A circuit and method for improving the metastable resolving time in low-power multi-state devices, including binary latches in integrated circuits. Upon detection of a metastable condition at the outputs of the integrated circuit, an increase in energy is locally applied to the decision making portion of the circuit. The localized application of energy to the decision making circuit reduces the metastability time constant tau (.tau.), thereby causing the circuit to resolve more rapidly to a stable operating state.
    Type: Grant
    Filed: February 27, 1996
    Date of Patent: August 4, 1998
    Assignee: Philips Electronics North America Corporation
    Inventor: Ronald L. Cline
  • Patent number: 5781028
    Abstract: A bidirectional universal serial bus (USB) includes switched terminations that are selectively activated to terminate the receiving end of the data bus in its characteristic impedance. The USB includes a twisted pair data cable that permits bidirectional data communication between a USB interface in a computer and a USB peripheral device. To control the bidirectional communication, the USB defines a transmit mode and a receive mode. Each end of the twisted pair data cable includes a selectively activatable switch termination that terminates the twisted pair data cable in its characteristic impedance when selectively activated. When the USB peripheral device is in the receive mode, the switched termination within the USB peripheral device is selectively activated so that the twisted pair data cable is terminated in its characteristic impedance. This reduces ringing and electromagnetic (EM) radiation on the twisted pair data cable.
    Type: Grant
    Filed: June 21, 1996
    Date of Patent: July 14, 1998
    Assignee: Microsoft Corporation
    Inventor: Joseph C. Decuir
  • Patent number: 5764084
    Abstract: A robust family of pre-conditioned complementary CMOS logic elements using scaled MOSFETs and a single clock phase which may be easily interconnected to form high speed logic networks. The family includes both N-type and P-type pre-conditioned logic elements using a skewed complementary CMOS structure to achieve low power and high speed. The logic elements achieve next generation CMOS performance yet are manufactured using present day processes and equipment. Logic element implementation is described in detail. A method for scaling the MOSFETs according to the present invention is provided, and several routing methods for reducing interconnection cross-talk are set forth.
    Type: Grant
    Filed: March 17, 1997
    Date of Patent: June 9, 1998
    Assignee: Microunity Systems Engineering, Inc.
    Inventor: Lavi A. Lev
  • Patent number: 5764074
    Abstract: The noise from the effects of currents through distributed capacitances between electrical circuitry on an integrated circuit chip and the chip substrate is minimized, especially for analog circuitry mixed on the chip with digital circuitry. The invention separates a plurality of bits in each digital word into a plurality (e.g. 2) of segments. A first register off the chip latches the first bits in each word with a first clock signal. A second register off the chip latches the second bits in each word with a second clock signal delayed from the first clock signal. The first register bits are latched on the chip with the first clock signal by a third register. The delayed second register bits are latched on the chip by a fourth register with the second clock signal or with a delayed first clock signal having the same delay as the second clock signal. Substrate ties for the third and fourth registers may be connected to at least one, preferably a plurality, of bonding pads on the chip.
    Type: Grant
    Filed: September 18, 1996
    Date of Patent: June 9, 1998
    Assignee: Brooktree Corporation
    Inventors: Michael D. Wykes, Michael J. Brunolli
  • Patent number: 5760601
    Abstract: A source terminated transmission line driver circuit with precise impedance matching capability and particularly suited for the output drivers of integrated circuit devices. The output transistors are operated in a current source mode using a common reference current, transistor dimension scaling, and current mirrors. The magnitude of the current provided by the output transistors is established to match the boundary conditions of the transmission line at turn-on and inherently matches the impedance characteristics upon the return of the reflected wave through conduction changes in the output transistors responsive to the transmission line voltage. The driver circuit transmits data signals over single or bus lines with minimum ringing.
    Type: Grant
    Filed: August 26, 1996
    Date of Patent: June 2, 1998
    Assignee: International Business Machines Corporation
    Inventor: Richard Francis Frankeny
  • Patent number: 5757205
    Abstract: A dynamic switching circuit for use in a domino circuit array is disclosed. The dynamic switching circuit includes a charge-saving transistor for preventing charge stored on the dynamic circuit's output node from discharging to ground. The charge stored on the output node is then fed back to a precharge control transistor to charge the dynamic node during the subsequent precharge/evaluate cycle.
    Type: Grant
    Filed: July 22, 1996
    Date of Patent: May 26, 1998
    Assignee: International Business Machines Corporation
    Inventors: Michael Kevin Ciraula, Donald George Mikan, Jr.
  • Patent number: 5748012
    Abstract: A pulsed logic circuit test methodology and circuitry therefor are disclosed. The methodology and circuitry allow the inhibiting of reset pulses, the ability to force resets and the ability to test the circuit in a pseudo-static mode of operation.
    Type: Grant
    Filed: January 5, 1996
    Date of Patent: May 5, 1998
    Assignee: International Business Machines Corporation
    Inventors: Michael Patrick Beakes, Barbara Alane Chappell, Terry Ivan Chappell, Bruce Martin Fleischer, Rudolf Adriaan Haring, Talal Kamel Jaber, Edward Seewann
  • Patent number: 5742182
    Abstract: A selector circuit with symmetry is disclosed. It steers input transition events to one of two outputs according to the value of a data input signal. The selector circuit includes a first flip-flop and a second flip-flop. Depending on the state of a data input, one of the two flip-flops is enabled and the other is disabled. The disabled flip-flop will be in a tristate mode. The enabled flip-flop continues storing its data, and may load the disabled flip-flop with this data. The selector circuit further includes pass gates to couple the outputs of the flip-flops based on the state of the event input.
    Type: Grant
    Filed: June 13, 1996
    Date of Patent: April 21, 1998
    Assignee: Sun Microsystems, Inc.
    Inventor: Ivan E. Sutherland
  • Patent number: 5736867
    Abstract: A reconfigurable buffer circuit capable of producing an active high or an active low output signal in accordance with a stored control parameter that is input to the buffer circuit. The reconfigurable buffer circuit has an output buffer that outputs a buffered output signal corresponding to an input signal. The reconfigurable buffer control circuit also has a control circuit that receives and stores an inputted control parameter, and receives at least one control signal from a control signal source. Based on the stored control parameter and the at least one control signal received from the control signal source, the control circuit produces the input signal.
    Type: Grant
    Filed: June 4, 1996
    Date of Patent: April 7, 1998
    Assignee: Cypress Semiconductor Corporation
    Inventors: Fred W. Keiser, Michael F. Maas
  • Patent number: 5729152
    Abstract: A memory device which utilizes a plurality of memory modules coupled in parallel to a master I/O module through a single directional asymmetrical signal swing (DASS) bus. This structure provides an I/O scheme having symmetrical swing around half the supply voltage, high through-put, high data bandwidth, short access time, low latency and high noise immunity. The memory device utilizes improved column access circuitry including an improved address sequencing circuit and a data amplifier within each memory module. The memory device includes a resynchronization circuit which allows the device to operate either synchronously and asynchronously using the same pins. Each memory module has independent address and command decoders to enable independent operation. Thus, each memory module is activated by commands on the DASS bus only when a memory access operation is performed within the particular memory module. The memory device includes redundant memory modules to replace defective memory modules.
    Type: Grant
    Filed: October 27, 1995
    Date of Patent: March 17, 1998
    Assignee: Monolithic System Technology, Inc.
    Inventors: Wingyu Leung, Winston Lee, Fu-Chieh Hsu
  • Patent number: 5726582
    Abstract: A termination network in an integrated circuit, and a control circuit for controlling the impedance of the termination network is described. The termination network comprises transistors for matching the impedance of the termination network with the characteristic impedance of a transmission line, which is connected to the termination network. The control circuit comprises a reference transistor which is integrated on the same integrated circuit as the termination network. The control circuit senses the impedance of the reference transistor and controls the reference transistor and the transistors in the termination network in such a way that the impedance is not affected by variations in temperature and in the manufacturing process of the integrated circuit.
    Type: Grant
    Filed: February 24, 1995
    Date of Patent: March 10, 1998
    Assignee: Telefonaktiebolget LM Ericsson
    Inventor: Mats Hedberg
  • Patent number: 5726588
    Abstract: A differential-to-CMOS level converter includes a differential-to-CMOS conversion circuit, first and second buffers and a cross-over adjustment circuit. The conversion circuit has first and second differential input terminals and first and second complementary output terminals. The first buffer has a buffer input coupled to the first complementary output and has a buffer output. The second buffer has a buffer input coupled to the second complementary output and has a buffer output. The cross-over adjustment circuit has first and second voltage measurement inputs coupled to the first and second buffer outputs and has first and second offset current outputs coupled to the first and second buffer inputs, respectively.
    Type: Grant
    Filed: August 15, 1996
    Date of Patent: March 10, 1998
    Assignee: LSI Logic Corporation
    Inventor: Alan Fiedler
  • Patent number: 5721508
    Abstract: Circuit for preventing the improper functioning of a CMOS output buffer that may occur due to the fact that since the output buffer P-channel may be coupled between a supply voltage and an output pad. If the pad is driven higher than the supply voltage by an external source, current may be injected into the parasitic diodes of the source/drain of the transistor.
    Type: Grant
    Filed: January 24, 1996
    Date of Patent: February 24, 1998
    Assignee: Cypress Semiconductor Corporation
    Inventor: David Brian Rees
  • Patent number: 5712581
    Abstract: A data qualification circuit (11) comprises a comparator (28), a first threshold circuit (33), and a second threshold circuit (41). A differential input signal is applied to the data qualification circuit (11). A first threshold circuit (33) is enabled by a zero logic state at the output of comparator (28). The first threshold circuit (33) sets a one logic state threshold voltage which the differential input signal must overcome for the comparator (28) to generate a one logic state. A second threshold circuit (41) is enabled by a zero logic state at the output of comparator (28). The second threshold circuit (41) sets a zero logic state threshold voltage which the differential input signal must overcome for the comparator (28) to generate a zero logic state.
    Type: Grant
    Filed: December 21, 1995
    Date of Patent: January 27, 1998
    Assignee: Motorola, Inc.
    Inventor: Scott Alan Kaylor
  • Patent number: 5708374
    Abstract: A self-timed control circuit for self-resetting CMOS logic circuitry provides handshaking between macros to ensure that all data inputted to a particular macro is maintained by the source macros until all data inputs have been received. A data output signal from a macro is maintained until the macro receives a complete signal from all receiving macros indicating that the receiving macros have received all data inputs supplied to them.
    Type: Grant
    Filed: May 14, 1996
    Date of Patent: January 13, 1998
    Assignee: International Business Machines Corp.
    Inventors: Christopher McCall Durham, Peter Juergen Klim
  • Patent number: 5701093
    Abstract: A plurality of stages of MOS gate circuits are connected in series and are driven with a 2-phase AC power source. The alternating speed of the power source is slower than the operation speed of internal circuit elements of the MOS gate circuits. A cutoff device such as a transistor is arranged on each side of each of the MOS gate circuits and is connected to the power source. The cutoff devices of each MOS gate circuit are conductive only when one phase of the power source is at high potential and the other at low potential. When the MOS gate circuit of a given stage (N.sub.i) is inactive, the MOS gate circuit of the next stage (N.sub.i+1) holds charge, to reduce an energy loss.
    Type: Grant
    Filed: March 15, 1996
    Date of Patent: December 23, 1997
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Seigo Suzuki
  • Patent number: 5698996
    Abstract: A technique is provided for signaling to a first data processing circuit that an output of a second data processing circuit is ready for processing by the first data processing circuit. An occurrence of a logic transition at an input of the second data processing circuit is detected, and a latch circuit is used to produce a detection signal indicative of the occurrence. In response to the logic transition, the output of the second data processing circuit is produced, and this output is provided to the first data processing circuit. In response to production of the detection signal, and after delaying for an amount of time adequate to permit the second data processing circuit to produce its output, a done signal is sent to the first data processing circuit.
    Type: Grant
    Filed: August 1, 1996
    Date of Patent: December 16, 1997
    Assignee: Texas Instruments Incorporated
    Inventor: Uming Ko
  • Patent number: 5691652
    Abstract: A system and method for improving alpha-particle induced soft error rates in integrated circuits is provided. Logic isolation circuits implemented using a substantially fewer number of pn-junctions are situated at the outputs of fast logic portions containing a substantially greater number of pn-junctions. The present invention reduces the vulnerability of a dynamic logic circuit of incurring alpha soft errors by effectively trading the probability of an isolation circuit composed of only a few pn-junctions incurring alpha-particle strikes with the probability of a fast logic circuit having substantially more pn-junctions incurring alpha-particle strikes. By reducing the number of pn-junctions susceptible to alpha-particle strikes, the present invention significantly lowers the potential alpha-particle induced soft error rate.
    Type: Grant
    Filed: February 20, 1996
    Date of Patent: November 25, 1997
    Assignee: Hewlett-Packard Co.
    Inventors: Robert H. Miller, Jr., John R. Spencer
  • Patent number: 5689196
    Abstract: Information is supplied to a bus in a wired logic function, the potential on the bus either being pulled down to ground level or remaining at supply level. The data line in a bus is split into two parts which are interconnected via the main current channel a transistor. Different supply voltages are used on the two parts. The control electrode of the transistor is connected to the lowest of the supply voltages. The transistor becomes conductive when either of the parts is pulled down. The transistor is non-conductive when none of the parts is pulled down.
    Type: Grant
    Filed: December 1, 1995
    Date of Patent: November 18, 1997
    Assignee: U.S. Philips Corporation
    Inventor: Herman Schutte
  • Patent number: 5680062
    Abstract: A gunn transceiver logic input circuit for use in a semiconductor memory device is capable of effectively inputting a signal having a small voltage difference. The gunn transceiver logic input circuit includes first and second input units which respectively input a GTL-level input signal and a GTL-level reference signal. First and second generating units with first and second level shifters respectively shift the GTL-level input signal and GTL-level reference signal to the ECL-level. An ECL buffer circuit compares the voltages between the ECL-level input signal and the ECL-level reference signal and generates first and second ECL-level output signals while maintaining a swing width of the GTL level signal.
    Type: Grant
    Filed: April 1, 1996
    Date of Patent: October 21, 1997
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Young-dae Lee, Chul-min Jung, Uk-rae Cho
  • Patent number: 5675263
    Abstract: A hot clock adiabatic gate, using CMOS technology, incorporates an ancillary transistor. The gate is energized by multiple clock signals of different phases to reduce power consumption. The output logic voltage of the gate can reach full-rail voltage by allowing the CMOS technology to discharge via the ancillary transistor. The hot clock adiabatic gate and associated ancillary transistor may be incorporated into various logic circuits, such as an inverter, a memory cell, a NAND gate, and a NOR gate. In one configuration, a CMOS inverter is controlled by four clock signals having four discrete phases. The CMOS inverter optimally includes a CMOS gate transistor pair wherein the semiconductor channels of two ancillary transistors are in series with the semiconductor channels of the CMOS gate transistor pair.
    Type: Grant
    Filed: November 21, 1995
    Date of Patent: October 7, 1997
    Assignee: Lucent Technologies Inc.
    Inventor: Thaddeus J. Gabara
  • Patent number: 5670898
    Abstract: A circuit topology for implementing combinational logic functions with large fan-in, high speed, and low power consumption using a combination of dynamic and static gates. The circuit topology includes a dynamic gate and a Pseudo-NMOS gate coupled to the dynamic gate.
    Type: Grant
    Filed: November 22, 1995
    Date of Patent: September 23, 1997
    Assignee: Silicon Graphics, Inc.
    Inventor: Emerson Fang
  • Patent number: 5670899
    Abstract: A semiconductor integrated circuit has an integrally formed logic circuit that is controlled by clock signals. The semiconductor integrated circuit includes a clock signal delay device that generates a plurality of clock signals having phases that are shifted from each other by a small amount with respect to a reference clock signal. The logic circuit is divided into a plurality (N number) of circuit blocks so that each of the circuit blocks is controlled by each of the associated plurality of clock signals to reduce noises. Noises in a CMOS integrated circuit are also reduced by controlled reference clock signals. A CMOS integrated circuit includes at least one CMOS gate with an input terminal being commonly connected to gates of a PMOS transistor and an NMOS transistor, and a latch circuit for transmitting data to the input terminal of the CMOS gate by clock signal control.
    Type: Grant
    Filed: November 9, 1995
    Date of Patent: September 23, 1997
    Assignee: Yamaha Corporation
    Inventor: Takayuki Kohdaka
  • Patent number: 5661411
    Abstract: A logic circuit employing feedback controlled loads to increase the response time and minimize power consumption. A plurality of input circuits are provided, each having means for coupling a first signal to a second signal. A first load responsive to the second signal provides a means for pulling up the first signal and a second load responsive to the first signal provides a means for pulling down the second signal. A driver responsive to the first and second signals is provided for generating an output voltage.
    Type: Grant
    Filed: January 5, 1996
    Date of Patent: August 26, 1997
    Assignee: Fujitsu Microelectronics, Inc.
    Inventor: Huy S. Nguyen
  • Patent number: 5656946
    Abstract: A voltage driving circuit for use in a semiconductor memory device. The voltage driving circuit includes a generator which generates a first voltage for an operating mode of the device, a generator which generates a second voltage for a standby mode, and a pair of switches connected between the voltage generators and an operating circuit, for selectively supplying the first and second voltages thereto. The first and second switches each have a control terminal, both of which are commonly coupled to a mode signal, for allowing external control of the voltage selection. The first and second voltages are preferably set relative to each other so as to reduce the subthreshold leakage current consumed by the semiconductor memory during a standby mode, while maintaining a desired operating speed during an operating mode.
    Type: Grant
    Filed: January 23, 1996
    Date of Patent: August 12, 1997
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Jai-Hoon Sim
  • Patent number: 5657456
    Abstract: An I/O bus interface cell includes a driver circuit having an input terminal fed by a logic signal and an output terminal to produce in response thereto a drive signal having selectable rise and fall time characteristics in accordance with a reference voltage provided to the driver. The I/O cell also includes a receiver circuit having an input terminal coupled to said output terminal of said driver with the receiver disposed to latch an unresolved, unamplified received signal prior to resolving the state of the signal. The I/O cell further includes a termination circuit having a terminal connected to the output of said driver, and having a selectable impedance characteristic at said terminal, with said selectable impedance being in accordance with a reference voltage provided to an input of said termination Circuit. Preferably, the I/O cell the driver, receiver and termination circuits are fabricated on a common semiconductor substrate.
    Type: Grant
    Filed: September 12, 1995
    Date of Patent: August 12, 1997
    Assignee: Digital Equipment Corporation
    Inventors: William B. Gist, Joseph P. Coyle
  • Patent number: 5646550
    Abstract: An output buffer (30) is connected to an output signal line and receives an internal power supply voltage, for example 3.3 volts, which is lower than a voltage, for example 5 volts, that other devices which may be connected to the output signal line are able to drive. To protect an output transistor (71) from the harmful effects of the higher voltages on the output signal line, the output buffer (30) includes a special bulk biasing circuit (80). The bulk biasing circuit (80) biases the bulk of the output transistor (71) at an internal power supply voltage when the output buffer is driving and when not driving to a voltage determined by the output signal. To prevent overlap currents, the output buffer (30) includes a special gate biasing circuit (100), which momentarily drives the gate of the output transistor (71) to a voltage equal to the internal power supply voltage when the output buffer (30) stops driving.
    Type: Grant
    Filed: February 22, 1996
    Date of Patent: July 8, 1997
    Assignee: Motorola, Inc.
    Inventors: Jules D. Campbell, Jr., Rene M. Delgado, Steve Lim
  • Patent number: 5646556
    Abstract: An apparatus is provided for precharging a conductor within a bus containing a plurality of conductors. The apparatus comprises a precharge driver which precharges alternating pairs of conductors to opposite rail voltages. By precharging pairs of conductors to alternating rails, the present apparatus can minimize the speed degradation problems associated with a transitioning target conductor within the bus. Precharging alternating pairs of conductors also minimizes crosstalk noise from transitioning neighbor conductors to a non-transitioning target conductor. The improved dynamic bus thereby demonstrates improvements in speed degradation and crosstalk noise as seen by a transitioning target conductor or non-transitioning target conductor, respectively.
    Type: Grant
    Filed: November 27, 1995
    Date of Patent: July 8, 1997
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Michael L. Longwell, Joseph P. Geisler
  • Patent number: 5633599
    Abstract: In a semiconductor integrated circuit provided with a circuit for testing an input buffer threshold voltage, an output node of a first logic gate having its output logic value determined by an output signal of an input buffer, and an output node of a second logic gate having its output logic value determined by a condition setting signal from an external source, are connected to a common signal line. When a standardized voltage for discriminating the threshold voltage is applied to the input buffer, if the input buffer malfunctions, the output signal of the first logic gate collides with the output signal of the second logic gate on the common signal line, so that a power supply current greatly increases.
    Type: Grant
    Filed: July 31, 1995
    Date of Patent: May 27, 1997
    Assignee: NEC Corporation
    Inventor: Shuji Kubota
  • Patent number: 5633605
    Abstract: A dynamic bus system with a central precharge device is disclosed that utilizes a controller circuit with a one-shot generator and write synchronizing circuits in combination with logic output modules having pull-up/down devices. The issuance of the output enable (OE) signals is interlocked with the turn-off of the precharge. Thus, data is written to the dynamic bus only when the precharge device is inactive, avoiding bus collisions. The resulting circuitry not only ensures the precharging of the bus before the data write to the bus, but will allow the synchronized OE signals to be issued during the same clock phase as the precharge signal.
    Type: Grant
    Filed: May 24, 1995
    Date of Patent: May 27, 1997
    Assignee: International Business Machines Corporation
    Inventors: Jeffrey S. Zimmerman, John A. Fifield, Christopher P. Miller, Robert E. Busch
  • Patent number: 5627489
    Abstract: A level shifter for shifting a digital signal input voltage to a digital signal output voltage and for rejecting voltage variations in the level shifter that would cause the level shifter to shift in error. The level shifter includes a trigger for triggering a pulse at each transition of the digital signal between an input supply voltage and an input reference voltage, a latch for switching the digital signal to one of an output supply voltage and an output reference voltage in response to each pulse from the driver and holding the digital signal at that voltage, and two half-shifters connected between the trigger and the latch for providing the pulse to said latch when the digital signal transitions. Each of the half-shifters include a selector circuit with series-connected current mirrors connected to a current source for providing a current to the current mirrors responsive to receipt of the pulse.
    Type: Grant
    Filed: June 22, 1995
    Date of Patent: May 6, 1997
    Assignee: Harris Corp.
    Inventor: Thomas A. Jochum
  • Patent number: 5619146
    Abstract: In a switching speed fluctuation detecting apparatus, an input terminal for receiving a signal having a definite time period, a series arrangement of at least one first logic circuit connected to the input terminal, a second logic circuit having a first input connected to the input terminal and a second input connected to an output of the series arrangement and an integrator connected to an output of the second logic circuit are provided.
    Type: Grant
    Filed: February 21, 1996
    Date of Patent: April 8, 1997
    Assignee: NEC Corporation
    Inventors: Masahiro Fujii, Yasuo Ohno, Tadashi Maeda, Takao Atsumo, Noriaki Matsuno, Keiichi Numata, Nobuhide Yoshida
  • Patent number: 5617041
    Abstract: In an EPLD, a feedback switching circuit is provided on a feedback line connected between a macrocell output line and a interconnect matrix wordline, the switching circuit including a memory element and a switch for passing a macrocell output signal from the output line to the interconnect matrix wordline when the memory element is in a first state, and for blocking the macrocell output signal when the memory element is in a second state. This prevents coupling noise in the interconnect matrix because unnecessary feedback signals are prevented from entering the interconnect matrix. In another embodiment, a method is provided in which unused macrocells produce counteractive switching signals in the interconnect matrix to reduce the coupling effect caused by a multiple concurrent switching event. In another embodiment, a sense amplifier is provided in which an EPROM shields coupling between wordlines and bitlines in an interconnect matrix.
    Type: Grant
    Filed: June 2, 1995
    Date of Patent: April 1, 1997
    Assignee: Xilinx, Inc.
    Inventors: Napoleon W. Lee, Wei-Yi Ku, Hy V. Nguyen, Sholeh Diba
  • Patent number: 5610539
    Abstract: A new logic family is identified that achieves much better speeds than CML logic gates. This new logic family operates with multiple inputs and a single logic level, using differential pairs of transistors for each input transistor of the multiple input. This new logic family enables high speed operation, or higher speed, than the prior art, together with lower operating current and a power-delay enhancement significantly increased over the prior art.
    Type: Grant
    Filed: January 30, 1996
    Date of Patent: March 11, 1997
    Assignee: Philips Electronics North America Corporation
    Inventors: Robert A. Blauschild, Daniel J. Linebarger
  • Patent number: 5606269
    Abstract: A circuit for detecting an input signal, the circuit having an input node and an output node, includes a first latch having a set input coupled to the input node, for detecting falling transitions at the input node. A second latch having a set input coupled to the input node, detects rising transitions at the input node. A first logic device, responsive to outputs of the first and second latches, detects that an input signal has been received at both the first and second latches. A second logic device, responsive to a complement output of both the first and second latches, resets both the first and second latches.
    Type: Grant
    Filed: October 26, 1995
    Date of Patent: February 25, 1997
    Assignee: International Business Machines Corporation
    Inventors: Dale E. Pontius, Robert Tamlyn
  • Patent number: 5606265
    Abstract: This invention is to reduce the power dissipation of a semiconductor integrated circuit chip when it is operated at an operating voltage of 2.5 V or below. To achieve the object, a switching element is provided in each circuit block within the semiconductor integrated circuit chip. The constants of the switching element are set so that the leak current in the switching element of each circuit block in their off-state is smaller than the subthreshold current of the MOS transistors within the corresponding circuit block. The active current is supplied to the active circuit blocks, while the switching elements of the non-active circuit blocks are turned off. Thus, the dissipation currents of the non-active circuit blocks are limited to the leak current value of the corresponding switching elements. As a result, the sum of the dissipation currents of the non-active circuit blocks is made smaller than the active current in the active circuit blocks.
    Type: Grant
    Filed: March 21, 1996
    Date of Patent: February 25, 1997
    Assignee: Hitachi, Ltd.
    Inventors: Takeshi Sakata, Kiyoo Itoh, Masashi Horiguchi
  • Patent number: 5604449
    Abstract: CMOS transistor logic circuitry is permitted to operate at higher power supply voltages while retaining lower voltage processing geometries by providing each input signal as dual input signals that track each other within two different voltage ranges. A shield voltage is provided approximately midway between the uppermost and lowermost power supply voltages. The first input signal ranges between the lowermost power supply voltage and the shield voltage, and the second input signal ranges between the shield voltage and the uppermost power supply voltage. The first and second input signals drive the gates of n-channel and p-channel CMOS switching transistors, respectively, the drain terminals of which are coupled to first and second output terminals, respectively. N-channel and p-channel shield transistors are connected in series between the first and second output terminals, and have their gate terminals coupled to the shield voltage.
    Type: Grant
    Filed: January 29, 1996
    Date of Patent: February 18, 1997
    Assignee: Vivid Semiconductor, Inc.
    Inventors: Richard A. Erhart, Thomas W. Ciccone
  • Patent number: 5602493
    Abstract: A semiconductor device includes a semiconductor switch connected between a power supply terminal and a signal input terminal, and a latch circuit for controlling the ON/OFF of the semiconductor switch, wherein the content of the latch circuit is reset only by a first reset signal and is not reset by a second reset signal for resetting a circuit other than the latch circuit.
    Type: Grant
    Filed: October 25, 1995
    Date of Patent: February 11, 1997
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Masayuki Konishi, Mitsuo Kusakabe
  • Patent number: 5598106
    Abstract: In a semiconductor integrated circuit constructed by thin film transistors (TFTs), an invertor circuit or a NAND circuit is formed by arranging a transmission gate circuit, a P-channel type TFT or an N-channel type TFT between a circuit including at least one P-channel type TFT and a circuit including at least one N-channel type TFT. The N-channel type TFT is earthed. Voltage drop produces by the arranged transmission gate circuit or P-channel or N-channel type TFT, so that the drain voltage of the earthed N-channel type TFT is decreased and an electric field near the drain region of the N-channel type TFT is decreased.
    Type: Grant
    Filed: May 19, 1995
    Date of Patent: January 28, 1997
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Yuji Kawasaki, Jun Koyama
  • Patent number: 5596284
    Abstract: The noise from the effects of currents through distributed capacitances between electrical circuitry on an integrated circuit chip and the chip substrate is minimized, especially for analog circuitry mixed on the chip with digital circuitry. The invention separates a plurality of bits in each digital word into a plurality (e.g. 2) of segments. A first register off the chip latches the first bits in each word with a first clock signal. A second register off the chip latches the second bits in each word with a second clock signal delayed from the first clock signal. The first register bits are latched on the chip with the first clock signal by a third register. The delayed second register bits are latched on the chip by a fourth register with the second clock signal or with a delayed first clock signal having the same delay as the second clock signal. Substrate ties for the third and fourth registers may be connected to at least one, preferably a plurality, of bonding pads on the chip.
    Type: Grant
    Filed: November 10, 1994
    Date of Patent: January 21, 1997
    Assignee: Brooktree Corporation
    Inventors: Michael D. Wykes, Michael J. Brunolli
  • Patent number: 5592103
    Abstract: A technique is provided for switching circuitry in a manner which allows the circuit to respond quickly to changes in some critical input signals expected to arrive last. In the preferred embodiment the circuits of this invention are provided in triple logic column form. A circuit will typically include at least two logic columns, each having three portions serially coupled between a high and a low potential source. The middle portion of each logic column is connected to the output node and to receive the critical input signal expected to arrive last, or the input signal with the critical timing requirement. The upper and lower portions of each logic column are connected to receive the remaining input signals, that is those input signals not expected to be changing at the time the critical input signal is received. Thus, the state of the upper and lower portions of the logic column can be "set-up" in advance, in readiness for the critical input condition.
    Type: Grant
    Filed: July 3, 1995
    Date of Patent: January 7, 1997
    Assignee: Sun Microsystems, Inc.
    Inventor: Ivan E. Sutherland
  • Patent number: RE35764
    Abstract: A new inverting output driver circuit is disclosed that reduces electron injection into the substrate by the drain of the circuit's pull-up field effect transistor. This is accomplished by adding additional circuitry that allows the gate voltage of the pull-up transistor to track the source voltage. The output circuit makes use of an inverter having an output node (hereinafter the intermediate node) coupled to V.sub.CC through a first P-channel FET, and to ground through first and second series coupled N-channel FETs, respectively. The gates of the P-channel FET and the first N-channel FET are coupled to and controlled by an input node. The inverter output node controls the gate of third N-channel FET, through which a final output node is coupled to V.sub.CC. The intermediate node is coupled to the final output node through a fourth N-channel FET, the gate of which is held at ground potential. The gate of the second N-channel FET is coupled to V.sub.
    Type: Grant
    Filed: September 13, 1996
    Date of Patent: April 7, 1998
    Assignee: Micron Technology, Inc.
    Inventors: Stephen L. Casper, Kevin G. Duesman