Patents by Inventor David James Megaw

David James Megaw has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 10135340
    Abstract: A controller may control a buck-boost regulator having an input voltage and an output voltage. The controller may include: circuitry that causes the output voltage of the buck-boost regulator to be at the bottom of a pre-determined voltage window when the input voltage goes below the bottom of the pre-determined voltage window: circuitry that causes the output voltage of the buck-boost regulator to be at the top of the pre-determined voltage window when the input voltage goes above the top of the pre-determined voltage window; and circuitry that causes the buck-boost regulator to pass the input voltage through the buck-boost regulator so as to cause the voltage output of the buck-boost regulator to be at the same level as the input voltage when the input voltage is within the pre-determined voltage window.
    Type: Grant
    Filed: September 11, 2017
    Date of Patent: November 20, 2018
    Assignee: Linear Technology Holding LLC
    Inventor: David James Megaw
  • Patent number: 8278886
    Abstract: A circuit for recovering charge at the gate of an output transistor arranged to drive the output of a switching circuit such as a switching regulator or controller. A substantial portion of the charge for each switching cycle is recovered under a wide range of load conditions for the switching circuit, e.g., no load, partial load, or full load. Also, charge recovery operates effectively with a switching circuit that is arranged to switch in a synchronous or asynchronous manner. Additionally, if the output voltage of a switching circuit is 12 or more volts, the amount of charge that can be saved can be relatively substantial.
    Type: Grant
    Filed: June 18, 2010
    Date of Patent: October 2, 2012
    Assignee: National Semiconductor Corporation
    Inventor: David James Megaw
  • Patent number: 7969127
    Abstract: A method and circuit for controlling the start-up of a shunt regulator that uses an error amplifier for normal operation in a linear range of a target value output voltage set by a reference voltage upon circuit start-up clamps the output voltage to a first level value below the target value, next applies regenerative positive feedback independent of the error amplifier to force the output voltage through a range where adverse conditions can occur to a second level value below the target value, and then releases the positive feedback near the target value where the error amplifier assumes control of the regulation.
    Type: Grant
    Filed: April 25, 2008
    Date of Patent: June 28, 2011
    Assignee: National Semiconductor Corporation
    Inventor: David James Megaw
  • Publication number: 20100259234
    Abstract: A circuit for recovering charge at the gate of an output transistor arranged to drive the output of a switching circuit such as a switching regulator or controller. A substantial portion of the charge for each switching cycle is recovered under a wide range of load conditions for the switching circuit, e.g., no load, partial load, or full load. Also, charge recovery operates effectively with a switching circuit that is arranged to switch in a synchronous or asynchronous manner. Additionally, if the output voltage of a switching circuit is 12 or more volts, the amount of charge that can be saved can be relatively substantial.
    Type: Application
    Filed: June 18, 2010
    Publication date: October 14, 2010
    Inventor: David James Megaw
  • Patent number: 7746153
    Abstract: A circuit for recovering charge at the gate of an output transistor arranged to drive the output of a switching circuit such as a switching regulator or controller. A substantial portion of the charge for each switching cycle is recovered under a wide range of load conditions for the switching circuit, e.g., no load, partial load, or full load. Also, charge recovery operates effectively with a switching circuit that is arranged to switch in a synchronous or asynchronous manner. Additionally, if the output voltage of a switching circuit is 12 or more volts, the amount of charge that can be saved can be relatively substantial.
    Type: Grant
    Filed: November 9, 2007
    Date of Patent: June 29, 2010
    Assignee: National Semiconductor Corporation
    Inventor: David James Megaw
  • Patent number: 7612609
    Abstract: A circuit for providing a self-stabilizing, differential load circuit with well controlled complex impedance to an amplifier is described. According to an embodiment, two pairs of transistors in a cross-coupled configuration, a degeneration resistor for each transistor, and parasitic capacitance cancelation capacitors provide a self-stabilizing, differential load. Small signal analysis of the circuit illustrates an impedance of the load circuit to be substantially equal to a combination of impedance values with substantially little dependence on transconductances and incremental resistances of the transistors over an extended frequency range. By employing well matched resistors, impedance of the load to the amplifier can be controlled and common mode feedback loops avoided, because a current source is not employed as a load. The use of parasitic capacitance cancelation capacitors can substantially increase the bandwidth of the amplifier.
    Type: Grant
    Filed: May 19, 2008
    Date of Patent: November 3, 2009
    Assignee: National Semiconductor Corporation
    Inventor: David James Megaw
  • Patent number: 7164259
    Abstract: An apparatus and method for producing an output reference voltage is provided. A voltage divider is configured to provide the output reference voltage from a bandgap reference voltage. The bandgap reference voltage is applied across a biased portion of the voltage divider. Additionally, a second-order temperature coefficient (TC) of the impedance of a controllable portion of the voltage divider is adjusted in response to a second-order trim signal. The first and zeroth order TCs of the controllable portion of the voltage divider are substantially independent of the second-order trim signal. In one embodiment, the controllable portion includes a resistor digital-to-analog converter (DAC) that is responsive to the second-order trim signal. The resistor DAC includes at least two different types of resistors. The second-order TCs of the two different types of resistors are substantially different.
    Type: Grant
    Filed: March 16, 2004
    Date of Patent: January 16, 2007
    Assignee: National Semiconductor Corporation
    Inventors: David James Megaw, Paul Ranucci
  • Patent number: 7088146
    Abstract: A half-latch that includes negative feedback circuitry is provided. The negative feedback circuitry causes the steady-state gain of the half-latch to remain high so that the overdrive voltage needed to change the state of the half-latch is significantly reduced. Additionally, the negative feedback is bypassed by capacitors at high frequencies so that the speed of the half-latch is substantially unaffected by the negative feedback.
    Type: Grant
    Filed: November 3, 2004
    Date of Patent: August 8, 2006
    Assignee: National Semiconductor Corporation
    Inventor: David James Megaw