Patents Assigned to Linear Technology
  • CURRENT RIPPLE REDUCTION CIRCUIT FOR LEDS
    Publication number: 20100141174
    Abstract: A powered LED circuit may include a power supply configured to generate and deliver an output current at a controllable average value with a substantial ripple component, one or more LEDs connected together, and a ripple reduction circuit connected to the power supply and to the one or more LEDs. The ripple reduction circuit may have a current regulator connected in series with the one or more LEDs which is configured to substantially reduce fluctuations in the current which flows through the one or more LEDs due to the ripple component of the output current, but not fluctuations in the current which flows through the one or more LEDs due to changes in the average value of the output current.
    Type: Application
    Filed: December 10, 2008
    Publication date: June 10, 2010
    Applicant: Linear Technology Corporation
    Inventor: Michael George Negrete
  • Programmable conduction mode control for switching circuits
    Patent number: 7733672
    Abstract: A control system that controls a switching circuit having a switching element and an inductive element coupled to an output of the switching element. The control system includes a switching control circuit that controls the switching element to operate the switching circuit in a first conduction mode of operation, such as a boundary conduction mode (BCM), in which current in the inductive element is maintained at a non-zero level during a first time period within each switching cycle. A conduction mode control circuit is configured for switching the switching circuit into a second conduction mode of operation, such as a discontinuous conduction mode (DCM), in which current in the inductive element is maintained at a non-zero level during a second time period within each switching cycle. The first time period differs from the second time period.
    Type: Grant
    Filed: November 29, 2006
    Date of Patent: June 8, 2010
    Assignee: Linear Technology Corporation
    Inventor: Xigen Zhou
  • Current control circuitry and methodology for controlling current from current constrained source
    Patent number: 7733061
    Abstract: Current control circuitry for controlling current supplied from a source, that may be a current-constrained source, to a load and a battery. A current limit control circuit limits current supplied by the source to the load in accord with a programmed current limit. Load current is measured, and an input charger control circuit controls magnitude of current to the battery based on the difference between measured load current and battery current programmed to be supplied to the battery, such that the sum of load current and battery current is maintained within the programmed current limit.
    Type: Grant
    Filed: December 29, 2004
    Date of Patent: June 8, 2010
    Assignee: Linear Technology Corporation
    Inventors: Roger A. Zemke, David B. Bell, Samuel Nork, Trevor Barcelo
  • POWER MEASUREMENT CIRCUIT
    Publication number: 20100127754
    Abstract: A power measurement circuit comprises: a transconductance rectifier arrangement including an input and configured to receive a sinusoidal input voltage signal; and an averaging filter for producing a time averaged DC output signal proportional to the mean square of the voltage at the input of the transconductance rectifier arrangement and representative of the average power of the input voltage signal within a range of voltages at the input.
    Type: Application
    Filed: November 25, 2008
    Publication date: May 27, 2010
    Applicant: Linear Technology Corporation
    Inventor: John P. MYERS
  • POWER MEASUREMENT CIRCUIT
    Publication number: 20100127755
    Abstract: A power measurement circuit and method are described. The circuit comprises: a transconductance rectifier arrangement including an input and configured to receive a periodically varying input voltage signal having an approximate 50% duty cycle; and an averaging filter for producing a time averaged DC output signal proportional to the mean square of the voltage at the input of the transconductance rectifier arrangement and representative of the average power of the input voltage signal within a range of voltages at the input.
    Type: Application
    Filed: December 18, 2008
    Publication date: May 27, 2010
    Applicant: Linear Technology Corporation
    Inventor: John P. MYERS
  • ACCELERATED RESPONSE TO LOAD TRANSIENTS IN PFM DC-TO-DC CONVERTERS
    Publication number: 20100123444
    Abstract: A pulse generator circuit in a DC-to-DC converter may be configured to generate pulses that have a frequency that increases in response to increases in the load on the DC-to-DC converter. The pulse generator circuit may be configured to cause each pulse to have a constant width. When the pulse reaches the end of the constant width and the magnitude of the current through an inductance in the converter is less than a threshold value, however, the pulse generator may be configured to extend the pulse until the magnitude of the current through the inductance reaches the threshold value. The pulse generator circuit may be configured to prematurely terminate each pulse if and at such time as the load voltage exceeds a target value by approximately half of the peak-to-peak voltage of the ripple component plus the noise component margin.
    Type: Application
    Filed: November 20, 2008
    Publication date: May 20, 2010
    Applicant: Linear Technology Corporation
    Inventors: Terry J. Groom, Jason Leonard
  • System and method for tracking a variable characteristic through a range of operation
    Patent number: 7714550
    Abstract: An analog control circuit is coupled to an apparatus having a variable characteristic over an operating range. A sensing circuit is coupled to the apparatus and the control circuit during the range of operation of the apparatus and is operative to sense the variable characteristic. The operating parameter of the apparatus is controlled to be set at a level corresponding to a prescribed criterion, which may be a maximum or minimum, of the characteristic sensed over the range of operation.
    Type: Grant
    Filed: October 20, 2005
    Date of Patent: May 11, 2010
    Assignee: Linear Technology Corporation
    Inventors: Talbott M. Houk, Joseph Duncan, Eugene L. Cheung
  • Method and system for variable-gain amplifier
    Patent number: 7714658
    Abstract: Method for a variable-gain amplifier (VGA). A plurality of attenuator nodes is serially connected via a first set of resistors between adjacent attenuator nodes to form an attenuator ladder and coupled to an AC input of the variable-gain amplifier. Each of the attenuator nodes includes a transistor and an RC circuitry that couples drain, gate, and source terminals of the transistor to a control signal for the attenuator node. The VGA also includes an amplifier that has an output produced based on an input to the amplifier connected to a plurality of coupled terminals, each of which is respectively from one of the plurality of attenuator nodes.
    Type: Grant
    Filed: November 24, 2008
    Date of Patent: May 11, 2010
    Assignee: Linear Technology Corporation
    Inventor: Walter Andrew Striflier
  • Power manager and power managing method for battery-powered application
    Patent number: 7710079
    Abstract: A power manager is configured to manage power for a battery-powered application. A power source, a load and a battery are interconnected through a circuit path. Power from the power source is provided to the load and battery by a switching regulator. Various implementations are presented.
    Type: Grant
    Filed: July 19, 2005
    Date of Patent: May 4, 2010
    Assignee: Linear Technology Corporation
    Inventors: Steven L. Martin, Trevor W. Barcelo, Samuel H. Nork, Roger A. Zemke, David J. Simmons
  • Dual-input DC-DC converter with integrated ideal diode function
    Patent number: 7709976
    Abstract: Novel system for supplying power from multiple power sources to a powered device has first and second input power supplies for respectively providing power from first and second power sources. An input selector circuit is responsive to the first and second input power supplies for producing an input power supply signal provided to a power regulator, such as a DC-DC converter, for generating a regulated output power supply signal. The power regulator includes a first transistor device controlled to support conversion of the input power supply signal into the output power supply signal if the input power supply signal is provided by the first input power supply, and a second transistor device controlled to support conversion of the input power supply signal into the output power supply signal if the input power supply signal is provided by the second input power supply.
    Type: Grant
    Filed: July 19, 2005
    Date of Patent: May 4, 2010
    Assignee: Linear Technology Corporation
    Inventor: John Phillip Bazinet
  • DC/DC converter with current limit protection
    Patent number: 7710700
    Abstract: A converter coupled to a DC voltage input and connectable to a load, includes a signal responsive switch coupled between a first circuit point and a second circuit point. Current flow is directed by the switch, when in a closed state, to the second circuit point to bypass the load. A regulator circuit has an output coupled to a control input of the switch. The regulator circuit has a first input for receiving a sensed load parameter, a second input for receiving a sensed current level signal at the second circuit point when the switch is in its closed state, and a third input for receiving a sensed current level signal at the second circuit point, measured directly, when the switch is in an open state. A fixed minimum time is set for the switch to be in the open state. The third input inhibits re-closing of the switch, providing current limit protection for the switch.
    Type: Grant
    Filed: January 10, 2005
    Date of Patent: May 4, 2010
    Assignee: Linear Technology Corporation
    Inventor: Eric Young
  • Multi-input power supply supervisor
    Patent number: 7711971
    Abstract: A system for monitoring multiple power supply signals with respect to a threshold has multiple inputs for receiving input power supply signals. A processing circuit of the system produces an output signal at a first level when the power supply signals have a prescribed relationship to a threshold value, and produces the output signal at a second level when at least one of the input power supply signals does not have the prescribed relationship to the threshold value. The processing circuit is configured for selecting the first level corresponding to a level of an input power supply signal at a pre-selected one of the inputs.
    Type: Grant
    Filed: June 28, 2006
    Date of Patent: May 4, 2010
    Assignee: Linear Technology Corporation
    Inventor: Robert Peter Jurgilewicz
  • Systems and methods for characterizing component ratios and generating a digital representation of same
    Patent number: 7705765
    Abstract: Circuits and methods for determining component ratios are provided. An analog to digital converter circuit may include comparison capacitors arranged in an upper group and a lower group for quantizing analog signals into the digital domain. In addition to determining the lower bits during an analog to digital conversion of an input sample, the lower group of comparison capacitors may also be used during calibration mode to quantize a ratio signal that represents the capacitor mismatches of the upper group rather than using a dedicated digital-to-analog converter to perform this function.
    Type: Grant
    Filed: October 10, 2008
    Date of Patent: April 27, 2010
    Assignee: Linear Technology Corporation
    Inventor: Heemin Yang
  • Combination of high-side and low-side current control in system for providing power over communication link
    Patent number: 7702302
    Abstract: A novel system for supplying power to a powered device over a communication link, such as an Ethernet link, has a current control mechanism that combines low-side current control circuitry with high-side current control circuitry. The low-side current control circuitry is coupled to a low-side power supply line for controlling low-side current flowing in the low-side power supply line. The high-side current control circuitry is coupled to a high-side power supply line for controlling high-side current in the high-side power supply line.
    Type: Grant
    Filed: August 21, 2006
    Date of Patent: April 20, 2010
    Assignee: Linear Technology Corporation
    Inventor: John Arthur Stineman, Jr.
  • Circuits and methods for canceling signal dependent capacitance
    Patent number: 7683695
    Abstract: Systems and methods for reducing the magnitude of signal dependent capacitance are provided. Capacitance canceling circuitry is operative to generate cancellation capacitance in response to the magnitude of a signal, which may be the same signal that produces the undesired signal dependent capacitance, to at least partially cancel the signal dependent capacitance.
    Type: Grant
    Filed: August 18, 2006
    Date of Patent: March 23, 2010
    Assignee: Linear Technology Corporation
    Inventors: Joseph L. Sousa, David M. Thomas
  • Single pass INL trim algorithm for networks
    Patent number: 7671770
    Abstract: A single-pass method of trimming a network, and a network manufactured according to the method, uses the assumption that the peak INL value is minimized by trimming all the structures in the network to a same target value based upon the boundary conditions of the discretely adjustable elements that make up the structures. Using this assumption, the number of targets that need to be simulated, can be greatly reduced making estimation of peak INL possible in a reasonable amount of testing or manufacturing time. The trim algorithm produces results that are optimum or substantially close to optimum and is guaranteed not to deteriorate the Peak INL compared to the untrimmed Peak INL. An auto-calibration system using the trim method is also provided so that the method can be used in a product in real time if desired.
    Type: Grant
    Filed: June 26, 2008
    Date of Patent: March 2, 2010
    Assignee: Linear Technology Corporation
    Inventor: Suat Sukuti Tukel
  • Method and system for bit polarization coding
    Patent number: 7656337
    Abstract: A method and system for converting a digital code. A digital signal is encoded to have a digital code having multiple binary bits. Substantially one half of the binary bits of the digital code is inverted to produce a modified digital code to reduce digital noise associated with the digital code.
    Type: Grant
    Filed: March 31, 2008
    Date of Patent: February 2, 2010
    Assignee: Linear Technology Corporation
    Inventors: Derek Redmayne, Richard James Reay
  • Switching regulator with variable slope compensation
    Patent number: 7656142
    Abstract: Controlled compensation for a switching regulator is attained by detecting switching duty cycle of the switching regulator, developing a compensation signal having a time duration that is related to the detected switching duty cycle percentage, and generating a duty cycle control signal for the regulator that is dependent in part on the developed compensation signal.
    Type: Grant
    Filed: July 14, 2005
    Date of Patent: February 2, 2010
    Assignee: Linear Technology Corporation
    Inventor: Chiawei Liao
  • Method and system for determining a clock input mode
    Patent number: 7656216
    Abstract: A method and system is provided for clock input mode selection. When a signal provided on one of two clock input terminals is received, the received signal is considered in connection with a second input signal in order to determine whether the first input signal and the second input signal satisfy a pre-determined condition. Based on whether the pre-determined condition is met, a clock input mode is selected that indicates whether the clock input terminals provide a differential clock input or a single-ended digital clock input.
    Type: Grant
    Filed: February 13, 2008
    Date of Patent: February 2, 2010
    Assignee: Linear Technology Corporation
    Inventor: Richard James Reay
  • Paralleling voltage regulators
    Patent number: 7642759
    Abstract: Circuits and methods for paralleling voltage regulators are provided. Improved current sharing and regulation characteristics are obtained by coupling control terminals of the voltage regulators together which results in precise output voltages and proportional current production. Distributing current generation among multiple paralleled voltage regulators improves heat dissipation and thereby reduces the likelihood that the current produced by the voltage regulators will be temperature limited.
    Type: Grant
    Filed: July 13, 2007
    Date of Patent: January 5, 2010
    Assignee: Linear Technology Corporation
    Inventor: Robert C. Dobkin