Patents Represented by Attorney Alan K. Stewart
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Patent number: 7284212Abstract: Reducing the number of computations required to pre-characterize cells in a cell-library. In an embodiment, a worst case vector which propagates most noise on an arc (combination of input pin and output pin) of a cell is determined, and NP characteristics and NIC are generated only for the worst case vector. Noise analysis is then performed using such curves generated from the worst case vector. Since curves corresponding to only the worst case vector may need to be generated, the computational requirements may be reduced. The search ranges in determining the immunity transition points forming the NIC may be reduced, according to some aspects of the present invention. The data corresponding to NIC may be used to generate NP curves, and vice versa to reduce computational requirements further.Type: GrantFiled: July 16, 2004Date of Patent: October 16, 2007Assignee: Texas Instruments IncorporatedInventors: Gaurav Kumar Varshney, Sreeram Chandrasekar
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Patent number: 7282964Abstract: A transition detect circuit includes: a first input port referenced to a first supply voltage node and a second input port referenced to a second supply voltage node. The circuit simultaneously monitors both ports for transitions, and once a transition occurs, directly generates the translated control signals at its output. Once a transition occurs at the inputs, the translated control signal is generated at the output within at most two gate delays. The circuit has very low quiescent current.Type: GrantFiled: September 29, 2005Date of Patent: October 16, 2007Assignee: Texas Instruments IncorporatedInventor: Mark B. Welty
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Patent number: 7279974Abstract: The fully differential large swing variable gain amplifier circuit includes: a first 5-transistor transconductor having a common mode node; and a second 5-transistor transconductor having a common mode node coupled to the common mode node of the first 5-transistor transconductor, wherein the second 5-transistor transconductor operates 180 degrees out of phase with the first 5-transistor transconductor.Type: GrantFiled: June 10, 2005Date of Patent: October 9, 2007Assignee: Texas Instruments IncorporatedInventor: Matthew D. Rowley
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Patent number: 7277828Abstract: A method, and associated storage medium containing software and a system, includes extracting a time domain impulse response from parameters that characterize a communication channel, generating a probability distribution function (PDF) of an output voltage based on the impulse response; and computing a relationship between bit error rate and voltage margin based on the final probability distribution function. Generating the PDF of the output voltage may comprise one or more of the following acts: quantizing the impulse response into a plurality of quantized levels, assigning taps to the quantized levels and determining a number of taps assigned to each quantized level, determining allowable voltage levels for each quantized level, and determining a probability of occurrence of each allowable voltage level, determining a PDF for each voltage level; and convolving all of the PDFs for the various voltage levels to obtain the PDF of the output voltage.Type: GrantFiled: February 12, 2004Date of Patent: October 2, 2007Assignee: Texas Instruments IncorporatedInventors: Sridhar Ramaswamy, Song Wu, Bhavesh G. Bhakta
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Patent number: 7277803Abstract: Determining the transition counts at various scan elements of a scan chain (for sequential scan tests) by merely examining the bits of an input vector and the expected results of evaluation. In an embodiment, assuming there are N bits of input vector (with the Nth bit being scanned in first and first bit being scanned in last) and N elements of a scan chain (with the first scan element receiving each bit first), the number of transition at Nth scan element equals an XOR of the Nth bit and the bit stored in the first scan element before scan-in operation. The number of transitions at Pth scan element then equals a sum of (XOR of (P+1)st bit and (Pth bit)) and the number of the transitions at the (P+1)st element. The transitions due to scan out operations can also be similarly determined. The computed number of transitions can be used for determining power dissipation during sequential scan test.Type: GrantFiled: January 4, 2006Date of Patent: October 2, 2007Assignee: Texas Instruments IncorporatedInventors: Senthil Arasu Thirunavukarasu, Devanathan Varadarajan
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Patent number: 7277920Abstract: The control flow underlying an application is represented in the form of a FSM (Finite State Machine) containing multiple states, transitions between states, and tasks associated with each transition. An execution block iteratively (in loops) transitions between the states according to the FSM representation, performing various operations according to the specified tasks in the transitions. In an embodiment, each state is associated with utmost one file providing inputs to the application. Such an approach provides an explicit control flow and easier way to develop and manage an application.Type: GrantFiled: April 21, 2003Date of Patent: October 2, 2007Assignee: Texas Instruments IncorporatedInventors: Roshin Lal Ramesh, Manisha Choithwani
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Patent number: 7277308Abstract: A technique to pre-charge a CAM block array that includes a plurality of CAM blocks that is organized into at least one rectangular array having rows each having a plurality of CAM blocks, a group of CAM cells and associated read/write bit lines connecting the group of CAM cells to a write/search driver and one or more precharge circuits. In one example embodiment, this is accomplished by precharging each read/write bit line substantially after completing a read cycle using the one or more precharge circuits. Then, precharging each read/write bit line substantially after completing a write cycle using a write/search bit line decoder and driver circuit, followed by precharging each search bit line in the CAM block array using the write/search bit line decoder and driver circuit substantially after completing a search operation.Type: GrantFiled: November 16, 2005Date of Patent: October 2, 2007Assignee: Texas Instruments IncorporatedInventor: Rashmi Sachan
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Patent number: 7277519Abstract: In one embodiment, a system for frequency and phase correction in a phase-locked loop (PLL) includes a phase frequency detector, first and second charge pumps respectively generating a first current and a voltage, a voltage-to-current (V2I) converter, a current summer, and a current-controlled oscillator (CCO). The phase frequency detector detects a frequency difference and a phase difference between a clock signal and a comparison signal, communicates the frequency difference to a first charge pump generating a first current, and communicates the phase difference to a second charge pump generating a voltage. The comparison signal is derived from an output signal of the PLL. The first charge pump modifies the first current according to the frequency difference and communicates the first current to the current summer. The second charge pump modifies the voltage according to the phase difference and communicates the voltage to the V2I converter.Type: GrantFiled: December 2, 2003Date of Patent: October 2, 2007Assignee: Texas Instruments IncorporatedInventors: Prasun K. Raha, T. Lakshmi Viswanathan, Richard E. Jennings
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Patent number: 7274581Abstract: A novel array fault testing for a TCAM system that includes a plurality of TCAM blocks that is organized into at least one rectangular array having rows each having a plurality of TCAM blocks, a group of TCAM cells and associated read/write bit lines connecting the group of TCAM cells to write driver and decoding block. The data decode bypass circuit of the TCAM cell provides a raw write feature to detect faults in a full suite of memory related tests. The debug input of the data debug bypass circuit of the TCAM cell when asserted in the test mode enables the TCAM cell to write raw, unencoded data into the array, and when deasserted in the test mode, enables the testing of the TCAM array. The resulting TCAM cell provides exhaustive fault testing thereby detecting and eliminating faults in TCAM.Type: GrantFiled: May 4, 2006Date of Patent: September 25, 2007Assignee: Texas Instruments IncorporatedInventors: Theo Jay Powell, Bryan D Sheffield, Rashmi Sachan
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Patent number: 7274916Abstract: A differential signal receiver and method is disclosed. One embodiment relates to a receiver for receiving a differential signal. The receiver includes a first voltage-to-current converter that converts the voltage received at a first input to a first current, and a second voltage-to-current converter that converts a voltage signal received at a second input to a second current. A current subtractor provides a difference current of the first and second currents that is indicative of the differential signal.Type: GrantFiled: July 23, 2004Date of Patent: September 25, 2007Assignee: Texas Instruments IncorporatedInventors: Mohammad A. Al-Shyoukh, Narasimhan R. Trichy
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Patent number: 7274233Abstract: A digital storage element comprises a master transparent latch that receives functional data signals from data input ports and scan data signals from a scan input port, the data input ports coupled to a four-input, one-output multiplexer adapted to receive the functional data signals and to selectively output one of the functional data signals. The digital storage element also comprises a slave transparent latch coupled to the master transparent latch, the slave transparent latch comprising dedicated functional data and scan data output ports. While operating in a scan mode, a first clock signal is used by the slave transparent latch and a second clock signal is used by the master transparent latch, wherein the first and second clock signals are non-overlapping.Type: GrantFiled: June 30, 2005Date of Patent: September 25, 2007Assignee: Texas Instruments IncorporatedInventors: Charles M. Branch, Steven C. Bartling, Dharin N. Shah
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Patent number: 7274716Abstract: An improved digital interface circuit that allows a plurality of data streams and other digital information to be output over a single channel. The digital interface circuit includes a plurality of data inputs, at least one control input, at least one clock input, and a single serial bit output. The digital interface circuit receives respective input data streams at the data inputs, receives digital control information at the control input, and receives a clock signal at the clock input. The control information is an N-bit data stream having a data rate of 1/N times the rate of the input data streams (N?1). The digital interface circuit generates a frame synchronization signal for providing framing for the N-bit data stream, and time-multiplexes the data and control information over the single serial bit output.Type: GrantFiled: June 18, 2003Date of Patent: September 25, 2007Assignee: Texas Instruments IncorporatedInventor: James R. Hochschild
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Patent number: 7274234Abstract: A digital storage element comprises a master transparent latch that receives functional data signals from data input ports and scan data signals from a scan input port, the data input ports coupled to a four-input, one-output multiplexer that receives the functional data signals and selectively outputs one of the functional data signals. The element comprises a slave transparent latch coupled to the master transparent latch and comprising dedicated functional and scan data output ports. While operating in a scan mode, a first clock signal is used by the slave transparent latch and a second clock signal is used by the master transparent latch, wherein the first and second clock signals are non-overlapping. A first transistor is coupled to the master transparent latch and a second transistor is coupled to the slave transparent latch. When activated, the first or second transistor resets the element.Type: GrantFiled: June 30, 2005Date of Patent: September 25, 2007Assignee: Texas Instruments IncorporatedInventors: Charles M. Branch, Steven C. Bartling, Dharin N. Shah
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Patent number: 7275223Abstract: A design management tool which automates the parallel validation of an entire integrated circuit while the individual blocks (together forming the integrated circuit) are designed. In an embodiment, a designer specifies various checkpoints associated with each design stage, and the specific information to be made available to a top level performing the validation. When each checkpoint is reached for a design block, the specified information is made available to the top level and the validation of the integrated circuit is performed up to that checkpoint. As a result, design closure of the integrated circuit can be obtained quickly.Type: GrantFiled: July 1, 2005Date of Patent: September 25, 2007Assignee: Texas Instruments IncorporatedInventors: Venkatasubramanyam Visvanathan, Sharad Arora, Sivakumar Ramaiyan
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Patent number: 7259979Abstract: An area efficient stacked TCAM cell for fully parallel search. The TCAM cell includes a top half circuit portion interconnected with a replicated bottom half circuit portion such that there is a shared match line between each of the half circuit portions. Each TCAM cell includes a pair of memory elements that is connected to a pair of associated compare circuits such that the interconnections between the memory elements and the compare circuits are substantially vertical in active MOS layers and substantially horizontal in metal layers. The memory elements and the compare circuits are connected such that they facilitate shorter interconnections and sharing of terminals at the boundary of adjacent cells. The resulting stacked TCAM cell provides shorter match lines, shared bit lines, and reduced silicon area to facilitate improved routing and performance.Type: GrantFiled: March 3, 2006Date of Patent: August 21, 2007Assignee: Texas Instruments IncorporatedInventors: Rashmi Sachan, Santhosh Narayanaswamy
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Patent number: 7253675Abstract: The bootstrapping circuit capable of sampling inputs beyond supply voltage includes: a bootstrapped switch MN20 coupled between an input node and an output node; a first transistor MP13 having a first end coupled to a control node of the bootstrapped switch MN20; a clock bootstrapped capacitor C13 having a first end coupled to a second end of the first transistor MP13; a second transistor MN27 coupled between the first end of the first transistor MP13 and a supply node, and having a control node coupled to a first clock signal node PHI; a third transistor MN26 coupled between the second end of the first transistor MP13 and the supply node; a charge pump having a first output coupled to a control node of the third transistor MN26; a level shifter having a first output coupled to a second end of the clock bootstrapped capacitor C13; a fourth transistor MN25 coupled between the supply node and a control node of the first transistor MP13, and having a control node coupled to a second output of the charge pump; aType: GrantFiled: June 22, 2005Date of Patent: August 7, 2007Assignee: Texas Instruments IncorporatedInventors: Devrim Y. Aksin, Mohammad A. Al-Shyoukh
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Patent number: 7236003Abstract: The H-bridge circuit with shoot through current prevention during power-up includes: a high side transistor; a low side transistor coupled in series with the high side transistor; pull down devices coupled to a control node of the high side transistor and to a control node of the low side transistor; and wherein the pull down devices are controlled by a pull down circuit including a Power On Reset circuit, monitoring the digital power supply such that the high side and low side transistors are OFF until the digital power supply has settled to a desired operating voltage.Type: GrantFiled: September 29, 2005Date of Patent: June 26, 2007Assignee: Texas Instruments IncorporatedInventors: Shanmuganand Chellamuthu, Brett E. Smith, Thomas A. Schmidt, Abidur Rahman
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Patent number: 7236552Abstract: A circuit for receiving multiple serial datastreams in parallel is disclosed. A bit clock is recovered from each data stream, there being one data bit for ach transition of the clock signal both positive and negative going. The phases of the bit clocks are compared and are adjusted by 180 degrees so that the positive going edges of all occur close to each other. The bits of each stream are assembled into words under the control of a word clock. In one embodiment a common word clock is derived form the set of bit clocks as a whole. In another embodiment each stream is provided with its own word clock which is aligned to positive edges of the respective bit clocks that are close to each other.Type: GrantFiled: July 22, 2003Date of Patent: June 26, 2007Assignee: Texas Instruments IncorporatedInventors: Iain Robertson, Richard Simpson, Michael Harwood
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Patent number: 7236556Abstract: In an integrated circuit receiving multiple serial data streams in parallel, a local clock is generated from each data stream and is synchronized with the data stream. Sometimes a data stream may have no transitions making it difficult to keep the clock synchronized with its data. A clock channel is provided, which always has edges. A circuit is provided for each data stream which measures the time elapsed since the data stream had an edge. After a certain period, the phase of the local clock is nudged towards that of the clock channel. Thereafter, the longer there are no edges on the data stream the more frequently nudges towards the phase of the clock channel are made.Type: GrantFiled: July 22, 2003Date of Patent: June 26, 2007Assignee: Texas Instruments IncorporatedInventors: Richard Ward, Giuseppe Surace, Andrew Joy
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Patent number: 7236034Abstract: The self correcting scheme to match pull up and pull down devices includes: a first comparator for comparing a common mode signal to a high reference limit; a second comparator for comparing the common mode signal to a low reference limit; a first flip flop having an input coupled to an output of the first comparator; a second flip flop having an input coupled to an output of the second comparator; a counter having inputs coupled to the first and second flip flops; and a delay device controlled by an output of the counter, wherein the delay device provides a pull down control signal that is delayed relative to a pull up control signal.Type: GrantFiled: July 27, 2004Date of Patent: June 26, 2007Assignee: Texas Instruments IncorporatedInventors: Wayne T. Chen, Narasimhan R. Trichy