With Field-effect Transistor Patents (Class 326/34)
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Patent number: 6008668Abstract: In an input circuit of a semiconductor device, a CMOS inverter has first and second transistors connected in series between an external power supply and ground and complementarily operating in accordance with an input signal. The first and second transistors have a connection point connected to an output terminal. A first switching device is connected in parallel to the second transistor and turned on/off. A comparator compares a voltage from the external power supply with a predetermined reference voltage and outputs a reference signal representing a comparison result. A logic circuit performs a logical operation between the reference signal from the comparator and the input signal supplied to an input terminal of the CMOS inverter and ON/OFF-controls the first switching device on the basis of a logical operation result.Type: GrantFiled: March 18, 1998Date of Patent: December 28, 1999Assignee: NEC CorporationInventor: Yasuhiro Saruwatari
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Patent number: 6002272Abstract: A domino logic circuit includes a clocked precharge stage coupled to a positive voltage rail with the precharge stage having an input. An evaluation network adapted to receive at least one input is coupled between the precharge stage and a common voltage rail. A static CMOS stage is coupled to the positive voltage rail, and includes an input and an output, the input being coupled to a junction formed by the precharge stage and the evaluation network. A negative voltage rail is coupled to the static CMOS stage to precharge the output negative.Type: GrantFiled: December 23, 1997Date of Patent: December 14, 1999Assignee: Intel CorporationInventors: Dinesh Somasekhar, Vivek De
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Patent number: 5994925Abstract: A pseudo-differential receiver is described which includes a bias generator circuit portion for providing a bias signal to a receiver circuit portion. The bias generator includes first and second load devices for establishing bias voltages at first and second nodes and also includes a first CMOS inverter biased by and coupled between the first and second nodes. The input of the first inverter is coupled to a reference voltage and the output of the inverter provides a bias voltage which is fed back to the gates of the first and second load devices. The biasing conditions on the first and second nodes bias the first inverter such that the threshold voltage of the first CMOS inverter is equal to the reference voltage. The biasing signal is used to bias loading devices in the receiver circuit portion. The receiver circuit portion includes loading and inverter devices that are electrically matched to the loading and inverter devices in the bias generator circuit portion.Type: GrantFiled: April 13, 1998Date of Patent: November 30, 1999Assignee: VLSI Technology, Inc.Inventor: D. C. Sessions
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Patent number: 5977796Abstract: A low voltage differential swing interconnect I/O buffer within an output buffer part comprising a voltage controlled current source, voltage controlled current sink, and a current switch and an input buffer part comprising a voltage controlled resistance. The output current and input resistance of the I/O buffer is determined by biasing voltages which are generated by on-chip reference circuits and applied to the voltage controlled components of the I/O buffer. Using two input reference voltages and a single reference resistor, the reference circuits dynamically adjust the biasing voltages so that the I/O buffer maintains the required output current and input resistance for all manufacturing process, supply voltage, and chip temperature variations.Type: GrantFiled: June 26, 1997Date of Patent: November 2, 1999Assignee: Lucent Technologies, Inc.Inventor: Thaddeus John Gabara
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Patent number: 5973541Abstract: The present invention provides an apparatus and method for repairing or improving the behavior of a tunable circuit of an integrated circuit (IC) when a target parameter exceeds a predetermined range due to a design and/or fabrication problem. The tunable circuit includes one or more tuning controllers for tuning a corresponding number of target circuits. Each tuning controller includes one or more registers and an optional decoder. Each target circuit includes a tunable portion and a functional portion. The functional portion can have one or more of a wide variety of functions including but not limited to logical gates, buffers, signal generators and amplifiers. The selectable parameters of the tunable circuit include timing delays, trip voltages, rise/fall times and/or output impedances. When a circuit designer wishes to tune the target parameter, an appropriate tuning pattern is latched into registers of the tuning controller.Type: GrantFiled: September 11, 1997Date of Patent: October 26, 1999Assignee: Sun Microsystems, Inc.Inventors: Sathyanandan Rajivan, Raoul B. Salem
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Patent number: 5955891Abstract: The control voltage .phi.1 outputted by the control voltage generating circuit 1 is at a low level in a range where an external supply voltage Vcc is lower than the threshold value of the transistor P1, but increases continuously in analog manner when the external supply voltage Vcc rises. After having matched the external supply voltage Vcc, the control voltage .phi.1 increases in the same way as the external supply voltage Vcc. By use of the control voltage provided with the characteristics as described above for an output circuit, controlled is the gate of a transistor P4 of a low-voltage operating output section 6 operative only at a voltage lower than a predetermined value. The transistor P2 of a full-voltage operating output section 5 of the output circuit is always operative on the basis of the control signal .phi.H of the data output control circuit 3.Type: GrantFiled: December 14, 1995Date of Patent: September 21, 1999Assignee: Kabushiki Kaisha ToshibaInventors: Eiichi Makino, Masaru Koyanagi
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Patent number: 5949270Abstract: A capacitor is connected between the gate of a transistor that is an object of threshold voltage compensation and an input terminal. A switching device is connected between a current source connected to one terminal of the transistor and the gate of the transistor. A second switching device is connected between the input terminal and a terminal to which a reference voltage is applied. The switching device is turned ON so that the transistor is diode-connected. The switching device is turned ON, thus applying the reference voltage to the input terminal. A reference voltage is applied to a current inflow terminal connected to another terminal of the transistor. After charge dependent on the threshold voltage of the transistor is accumulated in the capacitor, the switching device is turned OFF. With this control, a difference of a threshold voltage from another deriving from the fine structure of transistors as well as a difference in threshold voltage between adjoining transistors can be compensated for.Type: GrantFiled: March 19, 1997Date of Patent: September 7, 1999Assignee: Fujitsu LimitedInventor: Miyoshi Saito
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Patent number: 5933021Abstract: Circuits and methods of suppressing noise on a signal line are disclosed. A noise suppression pull-down circuit is coupled to a signal line which couples the output element of a first logic element to the input terminal of a second logic element. When the first logic element drives a logic low onto the signal line, the noise suppression pull-down circuit is activated to provide a weak pull-down on the signal line. When the first logic element drives a logic high onto the signal line, the noise suppression pull-down circuit is deactivated to prevent interference with the first logic element.Type: GrantFiled: June 18, 1996Date of Patent: August 3, 1999Assignee: Sun Microsystems, IncInventor: Bassam J. Mohd
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Patent number: 5917343Abstract: A MOS inverter within a large scale integrated circuit (LSI) includes a pair of circuits with the same performance. Each of the circuits includes a plurality of MOS inverters serially connected from the first stage to the last stage. Each of the MOS inverters is provided with an input such that the input of the MOS inverters of the first stage are formed to be adjacent one another.Type: GrantFiled: September 3, 1997Date of Patent: June 29, 1999Assignees: Yozan, Inc., Sharp Kabushiki KaishaInventors: Guoliang Shou, Kazunori Motohashi, Makoto Yamamoto, Sunao Takatori
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Patent number: 5909127Abstract: This invention provides a circuit and method to replace the passive resistive or statically biased active load devices with dynamically biased active load devices. This allows the load devices to present an effective load which varies depending on the state of the circuit output. The effective load and the time rate of change of the effective load can be dynamically optimized to improve circuit performance with changing conditions. The effective load is varied according to the state of the circuit by the use of time-delayed negative feedback. The biasing of the load devices is also capable to control the logic swing of the circuit. A bias generating circuit employing a dynamically biased active load is described. This provides a method for a family of logic circuits, especially CML circuits, to operate at low voltage and low power at high switching speeds, having symmetrical rise and fall times and well defined logic signal swings.Type: GrantFiled: February 14, 1996Date of Patent: June 1, 1999Assignee: International Business Machines CorporationInventors: Dale Jonathan Pearson, Scott Kevin Reynolds
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Patent number: 5900741Abstract: A CMOS buffer circuit having a trip point which is insensitive to variations in temperature, supply voltages and manufacturing processes. The circuit output stage has three series-connected MOS transistors including an N channel pull-down transistor connected between the buffer output and the circuit common, a first P channel pull-up transistor connected to a positive supply voltage and a second P channel pull-up transistor connected between the first P channel transistor and the buffer output. The gates of the first P channel transistor and the N channel transistor are connected together to form the buffer input. An N channel reference transistor is used to generate a reference current which is mirrored into the output stage by a third P channel transistor which is connected to the second P channel transistor of the output stage so as to form a current mirror.Type: GrantFiled: September 9, 1997Date of Patent: May 4, 1999Assignee: Micron Technology, Inc.Inventor: Frankie F. Roohparvar
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Patent number: 5892409Abstract: A CMOS compensation circuit receives compensation signals and provides a proportional compensation signal to an application circuit. The compensation circuit is implemented having a load for receiving at least one compensation signal. A device mirroring the load provides the application circuit with a compensation signal proportional to the received compensation signals. In a preferred embodiment, the compensation circuit provides a current controlled oscillator a compensation current to modify the bias of the oscillator. In a preferred embodiment, the compensation current is supplied by a fabrication variation monitor. The fabrication variation monitor supplies a signal to compensate for variations in the fabrication process, such as threshold voltage and effective length.Type: GrantFiled: July 28, 1997Date of Patent: April 6, 1999Assignee: International Business Machines CorporationInventor: David William Boerstler
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Patent number: 5883528Abstract: An input circuit to a semiconductor device may selectively accept different voltage logic levels (e.g., TTL or CMOS) as selected by a preset selection signal. The selection signal activates an N-type or P-type transistor in the input circuit which alters the threshold switching voltage of the input circuit logic. By altering the input threshold voltage, both TTL and CMOS input signals may be correctly triggered. An additional circuitry may be provided to allow a low voltage circuit (e.g., 3.3 Volts) to be tolerant of higher voltage inputs (e.g., 5 Volts). An isolation transistor isolates the input of the circuit from the high voltage signal, while a pulldown transistor pulls a high logic, high voltage signal down to supply voltage level.Type: GrantFiled: March 20, 1997Date of Patent: March 16, 1999Assignee: Cirrus Logic, Inc.Inventors: Abdul Qayyum Kashmiri, Junaid Ahmed Ahmed, Han My Kim
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Patent number: 5872464Abstract: The present invention provides a circuit and method using a floating PMOS transistor connected in series between the transistors of an input invertor. The floating PMOS transistor may be used to control the amount of current through the transistors. The gate of the floating PMOS transistor may be connected through a reference line to a duplicate of the input inverter stage. The duplicate stage is generally located in a reference block and fed with a stabilized reference voltage. Each couple (formed by the buffers input stage and the duplicate stage) functions as a differential comparator, which checks the input voltage against the reference voltage and rejects the power supply voltage variations which are perceived as a common-mode noise signal. The supply current is fixed by the reference voltage which reduces power consumption at high input voltages and high supply voltages.Type: GrantFiled: August 12, 1996Date of Patent: February 16, 1999Assignee: Cypress Semiconductor Corp.Inventor: Julian C. Gradinariu
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Patent number: 5859511Abstract: A circuit for operating a polyphase DC motor, such as the type having a plurality of "Y" connected stator coils, has circuitry for charging the coils at a rate which will reduce EMI and other noise, while maintaining an acceptable charge rate. The gate of a selected high side driving transistor is charged at a relatively high rate during a ramping phase. During the ramping phase, the gates of the selected transistor is charged to a voltage near the voltage needed to form a channel in the transistor for conduction. After the ramping phase, the gates are charged at a lesser rate in order to control the rate of charging of the stator coils to prevent noise.Type: GrantFiled: September 27, 1996Date of Patent: January 12, 1999Assignee: STMicroelectronics, Inc.Inventor: Francesco Carobolante
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Patent number: 5844426Abstract: A level shift is provided between a first level and a second level for a first and second compensatory signal. Power supply variations are measured and the levels are compensated for these power supply variations so that the power supply does not affect the first and second levels.Type: GrantFiled: June 13, 1996Date of Patent: December 1, 1998Assignee: Texas Intruments IncorporatedInventors: Benjamin Joseph Sheahan, Richard Charles Pierson
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Patent number: 5841309Abstract: An input buffer circuit has a switching point accurately set according to the input logic level, even when the input buffer circuit has a low supply voltage. The switching point is set according to an internal reference voltage of equal magnitude to the desired switching point that is applied to a current source. The current source accurately sources (or sinks) a current matching the current flowing in an input inverter when the input logic level substantially equals the reference voltage. At that point, the voltage at the output of the input inverter is substantially equal one half of the supply voltage. When the input logic level is slightly below or above the reference voltage, the output of the input inverter is near the supply or ground rail, respectively. Hysteresis is added to compensate for noise that may exist on the input logic signal.Type: GrantFiled: December 19, 1996Date of Patent: November 24, 1998Assignee: International Business Machines CorporationInventors: Anthony Richard Bonaccio, Wilbur David Pricer
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Patent number: 5838047Abstract: A semiconductor device includes a PMOS transistor and an NMOS transistor. In a standby state, a potential of Vcc level is applied to the substrate of the PMOS transistor and a potential of Vss level is applied to the substrate of the NMOS transistor. Therefore, the voltage between the source and substrate of the P and NMOS transistors becomes 0 V. In an active state, potentials that render the voltage between the source and substrate lower than the built-in potential are applied to respective substrates of the P and NMOS transistors. Therefore, the threshold voltage of the transistor is lowered in an active state than in a standby state, and almost no leakage current flows between the source and substrate.Type: GrantFiled: June 14, 1996Date of Patent: November 17, 1998Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Tadaaki Yamauchi, Kazutami Arimoto
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Patent number: 5825198Abstract: 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: GrantFiled: February 10, 1997Date of Patent: October 20, 1998Assignee: Hitachi, Ltd.Inventors: Takeshi Sakata, Kiyoo Itoh, Masashi Horiguchi
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Patent number: 5821769Abstract: A MOSFET circuit achieving high speed operation and low power consumption for a wide supply voltage range. MOSFET circuits are connected between a low threshold voltage CMOS circuit and a supply voltage and ground, as a power controller for switching power supply in response to sleep/active modes. High threshold voltage MOSFETs in the MOSFET circuits are gate biased by low threshold voltage MOSFETs, thereby preventing a current from flowing across the backgate terminal and the source terminal.Type: GrantFiled: April 18, 1996Date of Patent: October 13, 1998Assignee: Nippon Telegraph and Telephone CorporationInventor: Takakuni Douseki
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Patent number: 5801550Abstract: The pulse output circuit device comprises two transistors (2, 4) for constructing an output buffer, a transistor (7) connected between the output line (OUTP) of the output buffer and the high potential supply voltage (VDD), a transistor (8) connected between the output line (OUT) of the output buffer and the low potential supply voltage (GND), a control circuit (39) for applying a gate signal to the transistor (7), and a control circuit (40) for applying a gate signal to the transistor (8).Type: GrantFiled: November 29, 1995Date of Patent: September 1, 1998Assignee: Kabushiki Kaisha ToshibaInventors: Yasunori Tanaka, Ikue Yamamoto
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Patent number: 5798659Abstract: An input/output buffer including a bidirectional node, an output stage, an input stage, and a control circuit. The output stage has a first n-channel transistor coupled between the bidirectional node and a voltage supply node for pulling-up the bidirectional node, and first and second p-channel transistors coupled between the bidirectional node and the voltage supply node for pulling-up the bidirectional node. The input stage has a first inverter stage coupled between the bidirectional node and a first intermediate node and a second inverter stage coupled between the bidirectional node and a second intermediate node. The input stage also has a second n-channel transistor coupled between the first intermediate node and a ground node and a third n-channel transistor coupled between the second intermediate node and the ground node. The control circuit is coupled to the output stage and to the input stage and enables the output stage when in an output mode and disables the output stage when in an input mode.Type: GrantFiled: December 12, 1996Date of Patent: August 25, 1998Assignee: National Semiconductor CorporationInventors: Michael John Shay, Mark Douglas Koether
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Patent number: 5798658Abstract: This invention relates to source-coupled logic (SCL) which is a functional derivative of emitter-coupled logic (ECL). ECL is widely recognized as having the characteristics of high speed (low propagation delay) and low power supply noise generation. The SCL of the prior art succeeds at maintaining and improving the low noise characteristics of this architecture but does not fulfill the promise of high speed that one would expect from a current-mode logic. In addition, it uses a differential form of logic that is not as flexible and easy-to-use as a reference controlled or "single-ended" logic. The SCL disclosed here has the desired high speed properties and maintains the ease of use that is a property of reference controlled ECL. In addition, the reference controlled SCL of this invention provides new capabilities that make it even more flexible than ECL in generating logical switching functions.Type: GrantFiled: October 16, 1996Date of Patent: August 25, 1998Inventor: Paul M. Werking
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Patent number: 5796281Abstract: In an interface for an input signal with a small amplitude and a high bit rate, the output voltage of a receiver can become more indeterminate when the input signal voltage at the receiving end of a signal transmission line becomes equal to a reference voltage V.sub.ref. In the input buffer circuit of the CMOS current mirror type, a transistor Q.sub.2 is connected in parallel with another transistor Q.sub.1, where the conductivity types of both the transistors are the same and a reference voltage V.sub.ref is applied to the gate electrode of the transistor Q.sub.1. The transistor Q.sub.2 endows the input buffer circuit with a hysteresis characteristic, and the output power N1 of the input buffer circuit is supplied to the gate electrode of the transistor Q.sub.2.Type: GrantFiled: July 23, 1996Date of Patent: August 18, 1998Assignee: NEC CorporationInventors: Takanori Saeki, Yukio Fukuzo
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Patent number: 5789941Abstract: An ECL level/CMOS level logic signal interfacing device includes, connected in cascade, a circuit for generating an in-phase relationship with an ECL level input signal, a threshold inverter circuit receiving the in-phase signal at an inverter input and delivering an inverted in-phase signal, a shaping inverter circuit receiving the inverted in-phase signal and outputting a calibrated in-phase signal, and an output amplifier circuit receiving the calibrated in-phase signal and outputting an output signal to the CMOS level in phase relationship with the ECL level input signal. The circuits are supplied with a CMOS level supply voltage relative to a reference voltage.Type: GrantFiled: February 19, 1997Date of Patent: August 4, 1998Assignee: Matra MHSInventor: Remi Gerber
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Patent number: 5789942Abstract: A level converting circuit includes a first power supply line of a high potential, a second power supply line of a low potential, a third power supply line of a potential lower than that of the first power supply line by some degree, and a first internal power supply line. The level converting circuit also includes an inverter circuit configured to output an output potential equal to that of the second power supply line when an input signal is equal to a potential of the third power supply line, and another output potential equal to that of the first power supply line when the input signal is equal to a potential of the second power supply line.Type: GrantFiled: September 9, 1996Date of Patent: August 4, 1998Assignee: NEC CorporationInventor: Masayuki Mizuno
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Patent number: 5767699Abstract: A terminating element is connected between the terminating ends of a transmission line pair. A switching mechanism coupled to the originating ends of the transmission line pair steers a constant current through the transmission line pair. In response to input control signals, the switching mechanism steers the constant current in a complementary fashion into one of the lines of the transmission lines pair to creates a differential output voltage across the terminating element. Controlling the differential voltage by manipulating current flow allows for acurate control over V.sub.OH and V.sub.OL levels. Since the terminating element is connected between terminating ends of the transmission line pair, nearly all of the constant current flowing the driver contributes to the differential output voltage, thereby reducing power undesirable power dissipation.Type: GrantFiled: May 28, 1996Date of Patent: June 16, 1998Assignee: Sun Microsystems, Inc.Inventors: Robert J. Bosnyak, Robert J. Drost, David M. Murata
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Patent number: 5764077Abstract: An output buffer includes a pair of P-channel transistors and two cascode pull-down N-channel transistors to drive an output node. The output pull-up transistor has the gate thereof connected through a P-channel control transistor to an input driving signal. The control signal is isolated from the output node by a P-channel transistor which only conducts during overvoltage conditions. During normal operation, the control transistor is maintained in a conductive state to allow the gate of the output pull-up transistor to be pulled high and low. During an overvoltage condition, the P-channel transistor connected between the output node and the control transistor is turned on in order to effectively turn off the control transistor. The P-channel transistors in the output buffer are floating well-type transistors with the wells thereof tied to a switched voltage that is either the supply voltage during the normal operating mode or the output node during overvoltage conditions.Type: GrantFiled: February 5, 1996Date of Patent: June 9, 1998Assignee: Texas Instruments IncorporatedInventors: Bernhard Hans Andresen, Daniel Edmonson
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Patent number: 5751166Abstract: A method and a circuit for automatically adjusting a switching threshold of an input buffer circuit (100) to conform to an input signal V.sub.IN which can be from either a TTL or a CMOS logic family. A latch circuit (120) is initialized to set the switching threshold to that of one of the logic families. A level shifting circuit (130) has a switchable load which varies the switching threshold under the control of the latch circuit (120). The amplitude of the input signal V.sub.IN is detected in a threshold detector circuit (110). If the input signal V.sub.IN is a signal from the CMOS logic family, the latch circuit (120) changes state, switching the switchable load of the level shifting circuit (130) to adjust the switching threshold of the input buffer circuit (100).Type: GrantFiled: June 4, 1996Date of Patent: May 12, 1998Assignee: Motorola, Inc.Inventors: Jhy-Jer Shieh, Dandas K. Tang
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Patent number: 5748016Abstract: A driver circuit comprising (i) a pair of complementary MOS (CMOS) transistors connected in series and receiving an identical input signal, and (ii) a pair of control transistors changing a threshold voltage state of each of the pair of CMOS transistors by applying a plurality of voltages to a body terminal of each of the pair of CMOS transistors depending upon the ON/OFF state of each of the pair of CMOS transistors. Such a driver circuit is capable of reconciling a high-speed operation with a low power consumption under low power supply voltage conditions.Type: GrantFiled: March 20, 1996Date of Patent: May 5, 1998Assignee: NEC CorporationInventor: Susumu Kurosawa
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Patent number: 5748010Abstract: A logic signal level translation method and apparatus having very low dropout with respect to the powering rails and having a tri-state mode of operation allowing the output terminal to be driven to voltages beyond the highest supply voltage coupled thereto without significant power dissipation within the circuit. The output circuit includes well or body snatching devices which are controlled to assure that the wells of the output devices are able to follow extremes in voltage of the output terminal without biasing to conduction a PN junction of one or more of the output devices. A preferred embodiment is disclosed.Type: GrantFiled: January 3, 1996Date of Patent: May 5, 1998Assignee: Maxim Integrated ProductsInventor: Yusuf A. Haque
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Patent number: 5744982Abstract: A CMOS inverter has two p-channel FETs connected in series between V.sub.DD and the inverter output node, an upper FET connected to V.sub.DD and a lower FET connected to the output node. The gate of a upper FET and the gate of the inverter n-channel FET are connected to the circuit input through a series FET that protects the gate oxide of these FETs by turning off if a high voltage appears at the circuit input. The circuit is useful as a buffer that receives binary voltages that may be higher than the binary voltages of the circuits of the same chip. The gate of the upper p-channel FET is connected to the input and turns off fully to block a leakage current that would otherwise flow when the n-channel FET is turned on but the lower p-channel FET is left partly conducting by the voltage drop across the series FET.Type: GrantFiled: April 22, 1996Date of Patent: April 28, 1998Assignee: Taiwan Semiconductor Manufacturing Company, Ltd.Inventor: Ke-Cheng Chu
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Patent number: 5744978Abstract: A circuit for a sense amplifier (14) for use with a memory device (10). The circuit includes two devices (40 and 42) that are controlled by a selector (44). The first device (40) drives the sense amplifier (14) with a first current level. The second device (42) drives the sense amplifier (14) with a second current level, different from the first current level. The selector (44) is coupled to the first and second devices (40 and 42) so as to selectively couple one of the first and second devices (40 and 42) to the sense amplifier (14) based on a power supply voltage of the memory device (10).Type: GrantFiled: January 15, 1997Date of Patent: April 28, 1998Assignee: Micron Technology, Inc.Inventors: Gary R. Gilliam, Steve G. Renfro, Kacey Cutler, Roland Ochoa, Craig E. Schneider
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Patent number: 5742184Abstract: An input buffer circuit provides programmable resistors for inputs to a microprocessor and compensates for switching voltage timing differences caused when a selected programmable resistor is utilized for a selected input. In a preferred embodiment, an input buffer circuit has a weak transistor coupled between the input and an operating voltage source or ground, and a compensation circuit including two transistors in series between the operating voltage source or ground, and an output. When the weak transistor is on, thereby raising or lowering the input signal, one of the transistors is also on and the other transistor couples the output to the operating voltage source or ground.Type: GrantFiled: February 16, 1996Date of Patent: April 21, 1998Assignee: Cyrix CorporationInventor: Marvin W. Martinez, Jr.
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Patent number: 5736871Abstract: In an input buffer circuit for use in a semiconductor integrated circuit, comprising a differential pair formed of a pair of MOS transistors and receiving a reference voltage and an input signal supplied from an external, a first constant current source MOS transistor connected to the differential pair, and a load circuit connected to the differential pair, a second constant current source MOS transistor is connected in parallel to the first constant current source MOS transistor. A gate voltage of the second constant current source MOS transistor is controlled by a reference voltage convening circuit which receives the reference voltage.Type: GrantFiled: February 27, 1996Date of Patent: April 7, 1998Assignee: NEC CorporationInventor: Hiroyuki Goto
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Patent number: 5726590Abstract: A three-state buffer operating at a 3V power source supplies a three-state signal to a bus line pulled up to a 5V power source line. The three-state buffer includes CMOS transistors each receiving an output signal from a pre-stage buffer arid a transfer gate connected between the output of the CMOS transistors and the output terminal of the integrated circuit. The back-gate of the p-channel transistor of the CMOS is maintained at an intermediate potential between the 3V source line and the ground line while being in a floating state. The intermediate potential is presented by a serial three transistors. A low power dissipation and a high speed operation can be obtained by the circuit.Type: GrantFiled: June 3, 1996Date of Patent: March 10, 1998Assignee: NEC CorporationInventor: Toshio Isono
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Patent number: 5691654Abstract: A method of limiting or translating the voltages of input signals, and of generating output signals such that the input's high state and low state differ by a different voltage than the output's high and low state. The present invention also teaches a system comprising a level translator circuit having level translators controlled by an operational amplifier or by a Zener diode that regulates the voltage level on one side of the translators, the other side of the translators being regulated by an external power supply. The operational amplifier or Zener diode, in some embodiments of the present invention, ensures that the second side of the level translators are limited to a given reference voltage. Often, a resistor is connected to the Zener diode or to the output of the operational amplifier, and in some embodiments a resistor-capacitor network removes higher-frequency components from the voltage supply.Type: GrantFiled: December 14, 1995Date of Patent: November 25, 1997Assignee: Cypress Semiconductor Corp.Inventors: Gary W. Green, Mathew R. Arcoleo, Piyush Sevalia
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Patent number: 5670894Abstract: The present invention is to provide an output circuit, for a semiconductor circuit, capable of increasing the rise or fall time of an output signal without reducing the operating frequency of the output circuit, and thus effectively preventing occurrence of a malfunction due to an undesired change in the output signal caused by ringing, noise, or reflection occurring at the transition of the output signal. In the structure of present invention, an output circuit for a semiconductor circuit includes an input circuit, an output circuit including a transistor, and a control signal control circuit that lies between the input circuit and output circuit, outputs a control signal for use in driving the transistor in the output circuit, and changes the control signal according to a function of time.Type: GrantFiled: December 4, 1996Date of Patent: September 23, 1997Assignee: Fujitsu LimitedInventors: Toru Takaishi, Tetsu Tanizawa
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Patent number: 5668483Abstract: A CMOS buffer circuit having a trip point which is insensitive to variations in temperature, supply voltages and manufacturing processes. The circuit output stage has three series-connected MOS transistors including an N channel pull-down transistor connected between the buffer output and the circuit common, a first P channel pull-up transistor connected to a positive supply voltage and a second P channel pull-up transistor connected between the first P channel transistor and the buffer output. The gates of the first P channel transistor and the N channel transistor are connected together to form the buffer input. An N channel reference transistor is used to generate a reference current which is mirrored into the output stage by a third P channel transistor which is connected to the second P channel transistor of the output stage so as to form a current mirror.Type: GrantFiled: June 21, 1995Date of Patent: September 16, 1997Assignee: Micron Quantum Devices, Inc.Inventor: Frankie F. Roohparvar
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Patent number: 5666067Abstract: A voltage compensating CMOS input buffer converts input TTL signals to CMOS logic levels, and compensates for changing supply voltage by using a n-channel transistor to vary the effective size ratio of pairs p-channel to n-channel transistors making up an input inverter. The compensating transistor becomes operable with increasing supply voltage to help the n-channel input inverter transistors offset the p-channel input inverter transistors whose trip points would otherwise have been increased by increasing power supply voltage. As the power supply voltage decreases, the compensating transistor turns off, returning the input inverter to its original size ratio. The gate of the compensating transistor is coupled to the supply voltage through two diodes to control the amount of current flowing through the compensating transistor. Further trip point transistors in series with the compensating transistor have their gates coupled to the input signals to help stabilize the trip points.Type: GrantFiled: October 10, 1996Date of Patent: September 9, 1997Assignee: Micron Technology, Inc.Inventors: Joseph C. Sher, Manny K. F. Ma
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Patent number: 5661411Abstract: 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: GrantFiled: January 5, 1996Date of Patent: August 26, 1997Assignee: Fujitsu Microelectronics, Inc.Inventor: Huy S. Nguyen
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Patent number: 5661675Abstract: A logic circuit is described. The logic circuit generates a first signal state in response to a first set of input signals, generates a second signal state in response to a second set of input signals, activates a bypass switch in response to the first signal state, and bypasses a domino logic unit in response to the first signal state.Type: GrantFiled: March 31, 1995Date of Patent: August 26, 1997Assignee: Intel CorporationInventors: Kai J. Chin, Sudarshan Kumar
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Patent number: 5656952Abstract: According to embodiments of the present invention, a driver circuit, has first and second reference voltage rails for receiving first and second reference voltages, has first and second inputs for receiving an input differential signal and has first and second outputs for providing an output differential signal. The driver circuit comprises a first CMOS transistor, a second CMOS transistor, and first, second and third current sources. Positive voltage levels with respect to ground at the first and second outputs, are within typical acceptable ECL output voltage levels.Type: GrantFiled: November 13, 1995Date of Patent: August 12, 1997Assignee: Analog Devices, Inc.Inventors: Kevin J. McCall, David Reynolds
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Patent number: 5656946Abstract: 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: GrantFiled: January 23, 1996Date of Patent: August 12, 1997Assignee: Samsung Electronics Co., Ltd.Inventor: Jai-Hoon Sim
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Patent number: 5654645Abstract: A method and apparatus that controls and modulates the amount of hysteresis in a buffer in response to changes in operating conditions. The buffer comprises a first stage switching element and a hysteresis control element. The first stage switching element is configured to have a DC voltage trip point. As an input voltage, transitioning from a first state to a second state, is applied to the first stage switching element, the first stage switching element transitions as the input voltage reaches the DC voltage trip point. The transition of the first stage switching element enables the hysteresis control element to provide a feedback path biasing the first stage switching element. Consequently, as the input voltage transitions from the second logic level to the first logic level, the first stage switching element transitions at a voltage level offset from the DC trip point to provide hysteresis in the buffer.Type: GrantFiled: July 27, 1995Date of Patent: August 5, 1997Assignee: Cypress Semiconductor Corp.Inventor: Younes Lotfi
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Patent number: 5648734Abstract: An object of the present invention is to provide a buffer circuit little sensitive to a deviation from a threshold voltage of each of transistors. In order to achieve the above object, the present invention provides a typical buffer circuit comprising the following components.Type: GrantFiled: December 4, 1995Date of Patent: July 15, 1997Assignee: Oki Electric Industry Co., Ltd.Inventors: Tetsuya Tanabe, Satoru Tanoi
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Patent number: 5646551Abstract: This invention provides circuits which provide stable internally derived voltages for mixed mode large scale integrated circuits having SRAM, DRAM, and the like. The circuits use a summation of threshold voltages of metal oxide semiconductor field effect transistors to clamp voltages and a level detection circuit to compensate for variation in the primary supply voltage. A load detection and feedback circuit using a parasitic bipolar transistor provides voltage stability over a wide range of loading conditions.Type: GrantFiled: June 13, 1996Date of Patent: July 8, 1997Assignee: Etron Technology Inc.Inventor: Tah-Kang Joseph Ting
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Patent number: 5640104Abstract: A signal receiver for an interface of an MPU or a memory has a differential amplifier for receiving an input signal from an input/output line for the IPU and the memory, an inverter for receiving the output of the differential amplifier, and a feed-back section for providing the signal receiver with a transfer characteristic having a hysteresis with respect to the input signal of tile signal receiver. The feed-back section includes a feed-back signal path and a feed-back current path formed between a supply line and the output of the differential amplifier. The output signal of the gate is feed-backed to the feed-back current path as a control signal for making the feed-back current path active or inactive to shift tile voltage level of the output of the differential amplifier. The gate is not operated by a transient oscillation of the input signal so that unnecessary power consumption due to tile transient oscillation of the input of tile signal receiver is avoided.Type: GrantFiled: September 26, 1995Date of Patent: June 17, 1997Assignee: NEC CorporationInventor: Yasushi Matsubara
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Patent number: 5635859Abstract: The present invention provides a level converting circuit comprising: a differential output transistor circuit for amplifying a difference between two mutually complementary input logic signals; a first output transistor circuit for outputting an inverted output logic signal based on a signal output by the differential output transistor circuit; and a second output transistor circuit for outputting an uninverted output logic signal based on a signal output by the differential output transistor circuit, wherein the first output transistor circuit further comprises first and second field-effect transistors and the second output transistor circuit further comprises third and fourth field-effect transistors. The differential output transistor circuit comprises a combination of first, second, third, fourth and fifth bais components which are each resistive element or a field-effect transistors.Type: GrantFiled: March 3, 1993Date of Patent: June 3, 1997Assignee: Fujitsu LimitedInventors: Noboru Yokota, Noriaki Kogawa
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Patent number: 5635860Abstract: An overvoltage-tolerant self-biasing input/output buffer circuit having a p-channel field-effect transistor ("FET"), a first n-channel FET and a biasing circuit for biasing the body of the p-channel FET so as to prevent forward-biasing of the of the p-channel FET. The p-channel FET has a source connected to a first voltage, a gate connected to a first input, a drain connected to an output, and the body connected to a node. The first n-channel FET has a drain connected to the output, a gate connected to a second input, a body connected to a second voltage, and a source connected to the second voltage. The biasing circuit includes a second n-channel FET and a third n-channel FET. The second n-channel FET has a source and a gate connected to the first voltage, a drain connected to the node, and a body connected to the second voltage. The third n-channel FET has a drain connected to the node, a gate and a source connected to the output, and a body connected to the second voltage.Type: GrantFiled: December 28, 1995Date of Patent: June 3, 1997Assignee: Lucent Technologies Inc.Inventor: Eric H. Westerwick