Patents Assigned to Linear Technology
  • Class AB folded-cascode amplifier having cascode compensation
    Patent number: 7414473
    Abstract: A class AB folded-cascode amplifier having improved gain-bandwidth product, comprises a differential input circuit including a differential transistor pair coupled to a source of tail current and responsive to a differential input signal for conducting a first current, a cascode circuit coupled to the differential input circuit for supplying a second current thereto, and a class AB output stage. A compensation circuit is configured for feeding back mutually complementary compensation signals from an output node to the differential input circuit.
    Type: Grant
    Filed: July 27, 2006
    Date of Patent: August 19, 2008
    Assignee: Linear Technology Corporation
    Inventors: Surapap Rayanakorn, Robert C. Dobkin, Brendan J. Whelan
  • Flashless lead frame with horizontal singulation
    Patent number: 7414302
    Abstract: A lead frame is configured for use with a singulation apparatus that eliminates flash. A die pad is attached to sides of the frame by tie bars and peripheral portions. The peripheral portions have cutout sections defining openings that are bridged by lead frame segments. The apparatus applies a downward force to the lead frame segments and translates the downward force to a horizontal force applied to the tie bars. The singulation process confines movement of the lead frame metal to within the plane of the lead frame.
    Type: Grant
    Filed: August 8, 2006
    Date of Patent: August 19, 2008
    Assignee: Linear Technology Corporation
    Inventor: David Pruitt
  • Method of fabricating a semiconductor device with multiple gate oxide thicknesses
    Patent number: 7402480
    Abstract: The individual performance of various transistors is optimized by tailoring the thickness of the gate oxide layer to a particular operating voltage. Embodiments include forming transistors with different gate oxide thicknesses by initially depositing one or more gate oxide layers with intermediate etching to remove the deposited oxide from active regions wherein transistors with relatively thinner gate oxides are to be formed, and then implementing one or more thermal oxidation steps. Embodiments include forming semiconductor devices comprising transistors with two different gate oxide thicknesses by initially depositing an oxide film, selectively removing the deposited oxide film from active areas in which low voltage transistors having a relatively thin gate oxide are to be formed, and then implementing thermal oxidation.
    Type: Grant
    Filed: July 1, 2004
    Date of Patent: July 22, 2008
    Assignee: Linear Technology Corporation
    Inventors: François Hébert, Salman Ahsan
  • Bidirectional power conversion with multiple control loops
    Publication number: 20080164853
    Abstract: Bidirectional power conversion systems provide the ability to change power attributes to and from a component. Current bidirectional power conversion systems use a unidirectional power converter for each direction. The integration of the two normally independent power converters results in a bidirectional power converter with nearly half the size, weight, volume, cost and complexity. Described are embodiments of bidirectional power conversion systems that allow power transfer between two or more components without requiring the use of separate unidirectional power converters.
    Type: Application
    Filed: March 17, 2008
    Publication date: July 10, 2008
    Applicant: LINEAR TECHNOLOGY CORPORATION
    Inventors: Thomas P. Hack, Robert C. Dobkin
  • Range compression in oversampling analog-to-digital converters using differential input signals
    Patent number: 7397403
    Abstract: An analog-to-digital converter according to the invention is provided. The analog-to-digital converter preferably includes an analog input signal, a first reference signal, a second reference signal, and a range compression signal. The range compression signal is preferably characterized by a magnitude greater than the first reference signal and smaller than the second reference signal. In addition, when the analog input signal is sampled N times and the range compression signal is sampled N1 times, a compression factor related at least in part to the ratio N1/(N+N1) is obtained.
    Type: Grant
    Filed: July 7, 2006
    Date of Patent: July 8, 2008
    Assignee: Linear Technology Corp.
    Inventor: Florin A. Oprescu
  • Current-mode control for switched step up-step down regulators
    Patent number: 7394231
    Abstract: A switched regulator circuit provides step-up and step-down operation in which the level of the input voltage can be greater, equal to, or less than a preset controlled output voltage. A four switch arrangement or two switch arrangement provides buck, boost, and buck-boost regulation under constant frequency valley-peak current mode control. A single sense resistor may be utilized for sensing inductor current during only a short period during each duty cycle. As an alternative to the sense resistor, the switches themselves can be used to sense current during operation.
    Type: Grant
    Filed: February 8, 2005
    Date of Patent: July 1, 2008
    Assignee: Linear Technology Corporation
    Inventors: Randy G. Flatness, Xunwei Zhou
  • Switching regulator duty cycle control in a fixed frequency operation
    Patent number: 7388444
    Abstract: A clock oscillator system for use in providing the switching regulator duty cycle control in a fixed frequency (no cycle skipping) operation is provided. In one embodiment, the circuit according to the invention uses an analog feedback loop to extend the switch ON time of the clock cycle by controlling the oscillator charging current and, thereby, increase the duty cycle. Preferably, this circuit can achieve very high switching duty cycle and/or very low switching duty cycle in a PWM switching regulator operated in very low drop-out operation when very high duty cycle is required or in other conditions when very low duty cycle is required.
    Type: Grant
    Filed: October 3, 2005
    Date of Patent: June 17, 2008
    Assignee: Linear Technology Corporation
    Inventor: Chiawei Liao
  • Circuit and method for controlling hysteresis for bilevel signal transitions
    Patent number: 7382167
    Abstract: An output signal is controlled with adjustable hysteresis in response to a variable voltage input signal. One or more signals derived from the input signal are respectively compared with first and second reference voltages of different magnitudes. The output signal changes from a first state to a second state when one of the derived signals reaches a first reference voltage level threshold, and changes from the second state to the first state when a second one of the derived signals reaches a second reference level voltage threshold. A first derived signal may be varied to have a voltage magnitude that is greater or lesser than the voltage magnitude of a second derived signal while maintaining a positive hysteresis level. The circuit may be configured to output a signal representing an undervoltage and/or overvoltage condition of the input signal.
    Type: Grant
    Filed: April 11, 2005
    Date of Patent: June 3, 2008
    Assignee: Linear Technology Corporation
    Inventors: Christopher Bruce Umminger, Zhizhong Hou, James Herr
  • Non-perturbing power supply margin controller
    Patent number: 7382303
    Abstract: A power supply margin controller may alter the voltage of a control signal used to control the output voltage of a power supply. The controller may include a digital-to-analog converter having an input and an output, and a comparator having a first input coupled to receive the control signal, a second input coupled to the output of the digital-to-analog converter, and an output. The controller may include a processing system configured to deliver data to the input of the digital-to-analog converter based on the output from the comparator that causes signals at the inputs to the comparator to be substantially equal.
    Type: Grant
    Filed: September 20, 2006
    Date of Patent: June 3, 2008
    Assignee: Linear Technology Corporation
    Inventors: Matthew J. Maloney, Andrew J. Gardner
  • Switching regulator slope compensation generator circuit
    Patent number: 7378822
    Abstract: A slope compensation circuit that provides slope compensation in a switching regulator is provided. The slope compensation circuit preferably is adapted to receive an oscillator pulse train from a pulse width modulator oscillator and a modulator pulse train from a pulse width modulator. The circuit preferably includes a feedback loop that is responsive to the oscillator pulse train. The circuit preferably provides a slope compensation pulse train of ON and OFF states that is responsive in part to the feedback loop and in part to the pulse width modulator switch pulse train. The invention preferably achieves lower maximum slope compensation current by incorporating an analog feedback loop in the PWM system to start slope compensation preferably only slightly ahead of PWM switch-OFF. This preferably occurs independent of the PWM duty cycle.
    Type: Grant
    Filed: November 17, 2005
    Date of Patent: May 27, 2008
    Assignee: Linear Technology Corporation
    Inventor: Chiawei Liao
  • Methods and circuits for output over-voltage reduction in switching regulators
    Patent number: 7378826
    Abstract: Switching regulator Burst Mode control circuitry is provided for limiting voltage overshoot at the output of a switching regulator operating in power saving Burst Mode. The Burst Mode control circuitry may include regulator load current sensing circuitry which may be operative to put and maintain the regulator in the SLEEP state when the load current amplitude is below a threshold. The control circuitry may also include gated over-voltage comparator circuitry operative to reduce regulator output overshoot and to eliminate erroneous deactivation of the regulator switch circuitry when the regulator is not operating in Burst Mode. The gated over-voltage circuitry may include a one-shot timer circuit.
    Type: Grant
    Filed: January 5, 2006
    Date of Patent: May 27, 2008
    Assignee: Linear Technology Corp.
    Inventor: Chiawei Liao
  • High voltage MOS transistor with gate extension
    Patent number: 7374982
    Abstract: A high voltage MOS transistor with a gate extension that has a reduced electric field in the drain region near the gate is provided. The high voltage MOS transistor includes a first and second gate layers, and a dielectric layer between the gate layers. The first and second gate layers are electrically coupled togther and form the gate of the transistor. The second gate layer extends over the drain of the transistor above the dielectric and gate oxide layers to form the gate extension. The gate extension reduces the peak electric field in the drain by providing a wide area for the voltage to drop between the drain and the gate of the transistor. The dielectric layer also reduces the peak electric field in the drain near the gate by providing insulation between the gate and the drain. A lower electric field in the drain reduces the impact generation rate of carriers.
    Type: Grant
    Filed: June 28, 2004
    Date of Patent: May 20, 2008
    Assignee: Linear Technology Corporation
    Inventor: Francois Hebert
  • Systems and methods for reducing transient errors on digital to analog converters (DACs) deglitcher
    Patent number: 7375671
    Abstract: A digital to analog converter that receives a digital signal and that converts the digital signal to an analog input signal is provided. The converter may include a group of most significant bits. The group is decoded to drive a plurality of equivalent most significant segments. The converter may also include a second group of bits. The second group is decoded to drive a second plurality of equivalent segments.
    Type: Grant
    Filed: February 6, 2007
    Date of Patent: May 20, 2008
    Assignee: Linear Technology Corporation
    Inventor: James Lee Brubaker
  • Protection for switched step up/step down regulators
    Patent number: 7365525
    Abstract: A four switch voltage converter is regulated for buck mode and boost mode under constant frequency valley-peak current mode control. Protection circuits are responsive to output voltage and regulator current to prevent excessive current that otherwise might result from abnormally low output voltage short circuit, or spurious switching abnormalities during low duty cycle operation. The regulator control circuit is responsive to the protection circuits to automatically connect a regulator inductor between a common potential and the output to limit current.
    Type: Grant
    Filed: February 8, 2005
    Date of Patent: April 29, 2008
    Assignee: Linear Technology Corporation
    Inventors: Xunwei Zhou, Randy G. Flatness
  • Non-feedback implemented control of the output-common mode of a differential amplifier
    Patent number: 7365600
    Abstract: A differential amplification circuit includes a differential amplifier and common mode control circuitry configured to control output common mode of the differential amplifier. However, this control circuitry does not use feedback. The circuitry controls the output common mode in either, or in a combination of two ways, neither of which employs feedback from the output common mode. One control technique uses a dummy circuit and comparator to cancel out the effect of variations in process, temperature and supply voltage on output common mode. Another control technique measures input common mode voltage, compares the measured common mode to a reference, and based on the difference, applies a current to the output that compensates for the variation in output common mode that a given input common mode would otherwise cause.
    Type: Grant
    Filed: June 2, 2005
    Date of Patent: April 29, 2008
    Assignee: Linear Technology Corporation
    Inventor: Kristiaan Bernard Peter Lokere
  • Methods and circuits for frequency modulation that reduce the spectral noise of switching regulators
    Patent number: 7362191
    Abstract: The present invention comprises methods and circuits for spread spectrum frequency modulation that reduce peak spectral noise at the outputs or inputs of switching regulators. More specifically, the present invention modulates the operating frequency of the switching regulator in accordance with a frequency modulation waveform having a shape coordinated to a peak noise amplitude waveform that describes the correlation between the operating frequency of a switching regulator and the peak noise amplitude at the regulator's input or output absent spread spectrum frequency modulation.
    Type: Grant
    Filed: April 29, 2004
    Date of Patent: April 22, 2008
    Assignee: Linear Technology Corporation
    Inventors: Yuhui Chen, Doug LaPorte, Randy Guy Flatness, Robert C. Dobkin
  • Circuits and methods for detecting the presence of a powered device in a powered network
    Patent number: 7356588
    Abstract: Circuits and methods for detecting the presence of a powered device in a powered network connection and removing power from the powered network connection when no powered device is present are disclosed. The circuits and methods involve applying a time-varying voltage signal into an analog amplifier circuit that converts the voltage into a current indicative of the impedance of the connection. The analog amplifier circuit may be implemented with a dual-output trans-conductance amplifier that provides a digital voltage to indicate the removal of the powered device from the powered network connection.
    Type: Grant
    Filed: December 16, 2003
    Date of Patent: April 8, 2008
    Assignee: Linear Technology Corporation
    Inventors: John A. Stineman, Jr., Jacob Herbold
  • Range compression in oversampling analog-to-digital converters
    Patent number: 7348907
    Abstract: An analog-to-digital converter according to the invention is provided. The analog-to-digital converter preferably includes an analog input signal, a first reference signal, a second reference signal, and a range compression signal. The range compression signal is preferably characterized by a magnitude greater than the first reference signal and smaller than the second reference signal. In addition, when the analog input signal is sampled N times and the range compression signal is sampled N1 times, a compression factor that is based at least in part on N1/(N+N1) is obtained.
    Type: Grant
    Filed: July 7, 2006
    Date of Patent: March 25, 2008
    Assignee: Linear Technology Corp.
    Inventor: Florin A. Oprescu
  • Bidirectional power conversion with multiple control loops
    Patent number: 7348767
    Abstract: Bidirectional power conversion systems provide the ability to change power attributes to and from a component. Current bidirectional power conversion systems use a unidirectional power converter for each direction. The integration of the two normally independent power converters results in a bidirectional power converter with nearly half the size, weight, volume, cost and complexity. Described are embodiments of bidirectional power conversion systems that allow power transfer between two or more components without requiring the use of separate unidirectional power converters.
    Type: Grant
    Filed: April 25, 2005
    Date of Patent: March 25, 2008
    Assignee: Linear Technology Corporation
    Inventors: Thomas P Hack, Robert C Dobkin
  • Low power wide dynamic range RMS-to-DC converter
    Patent number: 7342431
    Abstract: An RMS to DC converter squares an a-c input signal to obtain a squared direct current voltage signal. The squared direct current voltage signal is applied to successive stages, each stage amplifying its received signal and detecting the amplified level of the signal within a confined range. The detected levels detected in the successive stages are added to produce an output d-c signal that is variable in linear proportion to logarithmic change in RMS voltage of the input signal. The voltage level of the squared direct current voltage signal can be clamped to a predetermined maximum voltage. To expand the range of detection, the squared direct current voltage signal is attenuated prior to detection in one or more of the stages.
    Type: Grant
    Filed: July 27, 2006
    Date of Patent: March 11, 2008
    Assignee: Linear Technology Corporation
    Inventor: Min Z. Zou