Patents Represented by Attorney, Agent or Law Firm Thompson & Knight, LLP
  • Patent number: 7400284
    Abstract: A circuit including a first element sampling noise from and discharging noise to a signal line in response to an input signal transitioning on selected edges of a clock signal. A second element samples noise from and discharges noise to the signal line in response to another input signal transitioning on other edges of the clock signal differing from the selected edges of the clock signal such that noise coupled into substrate and supply are independent of the input signal.
    Type: Grant
    Filed: March 29, 2004
    Date of Patent: July 15, 2008
    Assignee: Cirrus Logic, Inc.
    Inventors: Tom Gong Lei, Bruce Eliot Duewer, Stephen Timothy Hodapp
  • Patent number: 7393981
    Abstract: A catalytic process for producing ketones and particularly methyl-benzyl-ketone is provided. A catalyst comprising thorium oxide and a second metal oxide, preferably MnO, is formed on a substrate, preferably pumice. Phenylacetic acid and acetic acid are reacted in the presence of the catalyst to form methyl-benzyl-ketone.
    Type: Grant
    Filed: December 12, 2007
    Date of Patent: July 1, 2008
    Assignee: Property Development Corporation International, Ltd, Inc.
    Inventors: Alimamed Latif Shabanov, Elmira Mamedem Ramazanova
  • Patent number: 7395209
    Abstract: A digital audio decoder for receiving an encoded audio signal and decoding the audio signal. The digital audio decoder uses both real time computations and calculations pre-stored in a look-up table to decode the encoded audio signal. The digital audio decoder uses fixed point arithmetic but a variable word format to represent the intermediate computations and pre-stored look-up table entries.
    Type: Grant
    Filed: May 12, 2000
    Date of Patent: July 1, 2008
    Assignee: Cirrus Logic, Inc.
    Inventors: Vladimir Z. Mesarovic, Miroslav V. Dokic
  • Patent number: 7391842
    Abstract: Clock signal generation circuitry includes input circuitry for receiving a frequency control input signal and a clock signal and generating a memory address therefrom, a memory for storing digital data indexed by the memory address and representing real and imaginary parts of a complex digital waveform, and digital to analog conversion circuitry. The digital to analog conversion circuitry includes real-part digital to analog conversion circuitry for converting digital data retrieved from the memory and representing the real part of the complex waveform into a real-part analog signal and imaginary-part digital to analog conversion circuitry for converting digital data retrieved from the memory and representing the imaginary part of the complex waveform into an imaginary-part analog signal.
    Type: Grant
    Filed: May 11, 2006
    Date of Patent: June 24, 2008
    Assignee: Cirrus Logic, Inc.
    Inventor: John Laurence Melanson
  • Patent number: 7379834
    Abstract: A system for determining a data converter operating mode includes measurement circuitry operable to measure a master clock frequency of a master clock signal, the master clock frequency measurement biased by a past operating mode selection, and operable to measure a frequency ratio between a frequency of a data clock signal and the master clock frequency. A mapping system maps the measurements of the master clock frequency and the frequency ratio to an operating mode of the data converter. In an additional embodiment, the measurement circuitry biases the master clock frequency measurement based on a past master clock frequency measurement.
    Type: Grant
    Filed: May 24, 2005
    Date of Patent: May 27, 2008
    Assignee: Cirrus Logic, Inc.
    Inventors: Bruce Eliot Duewer, John Laurence Melanson
  • Patent number: 7376915
    Abstract: A method of forming a scan chain for testing an integrated circuit includes examining an interconnection of register elements in an integrated circuit design. A register element segment is identified which includes a source register element having an output and a destination register element having an input directly coupled to the output of the source register element. The segment is selectively coupled to another scan register element to form a portion of scan chain.
    Type: Grant
    Filed: October 7, 2004
    Date of Patent: May 20, 2008
    Assignee: Cirrus Logic, Inc.
    Inventors: Bruce Eliot Duewer, Richard Dean Putman
  • Patent number: 7352303
    Abstract: A system for determining a data converter operating mode includes measurement circuitry that measures a master clock frequency of a master clock signal received without a modification in frequency from a master clock signal source and that measures a frequency ratio between a frequency of a data clock signal and the master clock frequency. A mapping system maps the measurements of the master clock frequency and the frequency ratio to an operating mode of the data converter. In other embodiments, mapping systems map the measurements of the master clock frequency and the frequency ratio to an operating mode of the data converter based on mode priority constraints. In additional embodiments, mapping systems map the measurements of the master clock frequency and the frequency ratio to an operating mode of the data converter by narrowing the choices of master clock divide ratios and subsequently determining an operating mode from the frequency ratio.
    Type: Grant
    Filed: May 24, 2005
    Date of Patent: April 1, 2008
    Assignee: Cirrus Logic, Inc.
    Inventors: Bruce Eliot Duewer, John Laurence Melanson, Kartik Nanda
  • Patent number: 7348813
    Abstract: A method of interfacing circuits operating in different voltage domains includes receiving a first signal with a first circuit operating in a first voltage domain and generating a second signal with a second circuit operating in a second voltage domain. The second signal is level shifted between the first and second voltage domains with a level shifter and synchronized with the first signal with a third circuit operating in the first voltage domain.
    Type: Grant
    Filed: December 2, 2005
    Date of Patent: March 25, 2008
    Assignee: Cirrus Logic, Inc.
    Inventors: Kartik Nanda, Aryesh Amar, Rahul Singh, Jerome E Johnston
  • Patent number: 7350001
    Abstract: Methods and Apparatuses are provided for automatically converting a word length of sample data being transmitted over a serial link. A serial interface transmits and/or receives one or more data words comprising digital signals, a bit clock synchronizes transmission of individual bits, and a word clock is used to group the bits into sample words. A desired word length is determined based on the relationship between the bit clock and the word clock during the transmission or reception of a data word. Based on the desired word length, the sample data is either truncated or padded, and an appropriate amount of dither is added to the sample words to reduce the distortion and quantization artifacts introduced by the word length conversion.
    Type: Grant
    Filed: January 17, 2003
    Date of Patent: March 25, 2008
    Assignee: Cirrus Logic, Inc.
    Inventors: Dylan Alexander Hester, John Laurence Melanson, Steven Green
  • Patent number: 7330217
    Abstract: Chrominance phase error correction circuitry includes a demodulator for demodulating a received video color burst signal into first and second demodulated signals and signal generation circuitry for providing to the demodulator a demodulating signal for demodulating video color burst signal. Phase correction circuitry detects a phase error from the first and second demodulated signals and varies a phase of the demodulating signal to provide a corrected demodulating signal for demodulating a video chrominance signal with the demodulator during an active video period.
    Type: Grant
    Filed: October 20, 2004
    Date of Patent: February 12, 2008
    Assignee: Cirrus Logic, Inc.
    Inventor: Rahul Singh
  • Patent number: 7324544
    Abstract: Synchronization within a common communication channel having designated transmission time slots for various devices of a computer network is maintained by allowing transmissions within the channel outside of a network device's designated time slot when a clear channel assessment indicates that a previous time slot is not being utilized by its associated device and/or upon receipt of an indication of the end of a transmission of another device in the network. The clear channel assessment preferably takes into account the device's designated transmission time slot within the communication channel with respect to those of other network devices and may be a time period that is the product of a predetermined clear channel waiting time and a numerical representation of the device's designated transmission time slot within the communication channel with respect to those of other network devices. The clear channel waiting time itself may be specified by a network master device as part of a network connection process.
    Type: Grant
    Filed: February 18, 2003
    Date of Patent: January 29, 2008
    Assignee: Cirrus Logic, Inc.
    Inventors: Rajugopal Gubbi, Donia Sevastian, Natarajan Ekambaram, Nirmalendu Bikash Patra
  • Patent number: 7308027
    Abstract: A pulse width modulation circuit for driving a full-bridge output load includes a pulse width modulation stage for generating, from an input data stream, a pulse width modulated data stream for driving a terminal of a full-bridge output load and another pulse width modulated data stream for driving another terminal of the full bridge output load. A delay circuit delays the another pulse width modulated data stream relative to the pulse width modulated data stream such that edges of the another pulse width modulated data stream and edges of the pulse width modulated data stream are temporally spaced.
    Type: Grant
    Filed: April 21, 2004
    Date of Patent: December 11, 2007
    Assignee: Cirrus Logic, Inc.
    Inventors: Johann Guy Gaboriau, Melvin L. Hagge, Lingli Zhang, John Laurence Melanson
  • Patent number: 7286069
    Abstract: A system for determining a data converter operating mode includes measurement circuitry for measuring master clock frequency of a master clock signal and a frequency ratio between a frequency of a data clock signal and the master clock frequency and a mapping system for mapping the measurement of the frequency ratio to an operating mode of the data converter. The mapping system generates a set of candidate divide ratios for dividing the master clock frequency to generate corresponding internal master clock frequencies of an internal clock signal and determines the lowest divide ratio which generates a supported internal master clock frequency. In an alternate embodiment, the mapping system determines the divide ratio required by a filter of the data converter by dividing the data clock to master clock frequency ratio by a data clock to internal clock frequency ratio between the data clock frequency and the frequency of an internal clock signal.
    Type: Grant
    Filed: May 24, 2005
    Date of Patent: October 23, 2007
    Assignee: Cirrus Logic, Inc.
    Inventors: Bruce Eliot Duewer, John Laurence Melanson, Kartik Nanda
  • Patent number: 7262654
    Abstract: An operational amplifier including at least one amplifier stage and chopping circuitry for chopping an input signal to the amplifier stage and an output signal from the chopping signal having a frequency randomly varying within the selected frequency band.
    Type: Grant
    Filed: January 14, 2005
    Date of Patent: August 28, 2007
    Assignee: Cirrus Logic, Inc.
    Inventors: Murari Kejariwal, Gowtham Vemulapalli, John Laurance Melanson
  • Patent number: 7252039
    Abstract: A ballast discharge car having at least one non-pivoting transverse conveyor disposed beneath a hopper for distributing the ballast between the rails, near the outside of the rails, and well beyond the outside of the rails in a stockpiling application. The speed, direction, and angle of each conveyor is adjustable so that the ballast can be selectively cast a wide range of distances from the outside of the rails.
    Type: Grant
    Filed: December 26, 2003
    Date of Patent: August 7, 2007
    Assignee: BNSF Railway Company
    Inventor: John H. Bosshart
  • Patent number: 7251231
    Abstract: A communication channel is controlled so as to dynamically accommodate network client requests for access thereto. The communication channel may be supported on a wireless link, such as a spread spectrum wireless link, and client requests for access thereto may be dynamically accommodated by allocating time slots for client transmissions on the wireless link. Providing a quiet time slot within which clients may request access to the communication channel may accommodate various client requests for access to the communication channel. These quiet slots may exist with other forward and reverse time slots which are superimposed on the communication channel, each forward and reverse time slot including one or more data frames. The forward and reverse time slots are preferably fixed, but negotiable, time periods. Each of the data frames may include a plurality of data packets, each of the data packets being variable in length.
    Type: Grant
    Filed: February 21, 2003
    Date of Patent: July 31, 2007
    Assignee: Cirrus Logic, Inc.
    Inventor: Rajugopal Gubbi
  • Patent number: 7248186
    Abstract: A method of reducing noise in a system utilizing a serial port includes generating a data word having a selected number of bits and ensuring that a last bit of the data word corresponds to a first bit of a next data word. The data word is output through the serial port and the next data word switched for output through the serial port in response to an event.
    Type: Grant
    Filed: March 22, 2005
    Date of Patent: July 24, 2007
    Assignee: Cirrus Logic, Inc.
    Inventor: Bruce Eliot Duewer
  • Patent number: 7236109
    Abstract: A system for determining a data converter operating mode includes measurement circuitry which measures a master clock frequency, measures a frequency ratio between a frequency of a data clock signal and the master clock frequency, and measures a selected operating condition of the data converter. A mapping system maps the measurements of the master clock frequency, the frequency ratio, and the selected operating condition, to an operating mode of the data converter. In another embodiment, the measurement circuitry adjusts the measurement of the master clock frequency in response to a measurement of the operating conditions of the data converter. In a further embodiment, user input information varies the measurement of the master clock frequency.
    Type: Grant
    Filed: May 24, 2005
    Date of Patent: June 26, 2007
    Assignee: Cirrus Logic, Inc.
    Inventors: Bruce Eliot Duewer, John Laurence Melanson
  • Patent number: 7236488
    Abstract: An intelligent routing and switching system includes an interface for coupling said system to an external network and a switch fabric for selectively routing bits of data being exchanged with an external network through the interface. The switch fabric includes an array of multiport switching elements each including switches and memory elements for introducing programmable delays in selected ones of the bits being routed. The routing and switching system further includes a first controller for implementing a routing table and scheduler in accordance with a sequencing graph to route bits of data through the switch fabric and a second controller for generating the sequencing graph and for allocating input and output slots for inputting and outputting data through the interface.
    Type: Grant
    Filed: August 9, 2002
    Date of Patent: June 26, 2007
    Inventor: Gautam Kavipurapu
  • Patent number: 7230454
    Abstract: An output driver circuit including a transistor for pulling down an output terminal voltage and a charge pump for driving an input of the transistor to pull-down the output terminal voltage substantially to zero volts in response to a selected level of an input signal.
    Type: Grant
    Filed: February 18, 2005
    Date of Patent: June 12, 2007
    Assignee: Cirrus Logic, Inc.
    Inventors: Joseph Jason Welser, Johann Guy Gaboriau