Patents by Inventor David Chalmers Schie

David Chalmers Schie 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: 7622820
    Abstract: A switch-mode power supply (SMPS) with auto-tuning using limit-cycle oscillation response evaluation provides optimized performance with reduced capacitance and inductance requirements for a given design. During operation of the SMPS, parameters of the converter are extracted, and the feedback and/or feed-forward compensation is adjusted to either hold the loop bandwidth of the converter near the critical bandwidth of the output capacitors, or maintain output voltage transients within a specified limit. The compensator response is either periodically updated, or is updated in response to an event, such as detection of a transient voltage spike having a characteristic that exceeds one or more predetermined thresholds.
    Type: Grant
    Filed: April 23, 2008
    Date of Patent: November 24, 2009
    Inventors: Aleksandar Prodic, Zhenyu Zhao, David Chalmers Schie
  • Patent number: 6958920
    Abstract: A switching power converter and method of controlling an output voltage thereof using predictive sensing of magnetic flux provides a low-cost switching power converter via primary-side control using a primary-side winding. An integrator generates a voltage that represents flux within a magnetic element by integrating a primary-side winding voltage. A detection circuit detects the end of a half-cycle of post-conduction resonance that occurs in the power magnetic element subsequent to zero energy level in the power magnetic element. The integrator voltage is stored at the end of the half-cycle and is used to determine a sampling point prior to or equal to the start of post-conduction resonance in a subsequent switching cycle of the power converter. The primary-side winding voltage is then sampled at the sampling point, providing an indication of the output voltage of the power converter by which the output voltage of the converter can be controlled.
    Type: Grant
    Filed: May 4, 2004
    Date of Patent: October 25, 2005
    Assignee: Supertex, Inc.
    Inventors: Alexander Mednik, David Chalmers Schie, James Hung Nguyen, Wei Gu
  • Patent number: 6940733
    Abstract: A switch state controller generating a pulse train is used in a power converter utilizing a plurality of converter stages all simultaneously controlled by a single switch controlled by said pulse train. On time of the pulse train is controlled according to an input or interim node characteristic of the supply and period is controlled by a characteristic of the output of the converter. This allows development of AC-to-DC converters, including power-factor-correction converters, and DC to DC converters with high conversion ratio with minimal parts count & high reliability.
    Type: Grant
    Filed: August 22, 2003
    Date of Patent: September 6, 2005
    Assignee: Supertex, Inc.
    Inventors: David Chalmers Schie, Alexander Mednik, James Hung Nguyen, Sang Ton Ngo, Khai Minh Le, Wei Gu, Larry Kerenyi
  • Publication number: 20040264216
    Abstract: A switching power converter and method of controlling an output voltage thereof using predictive sensing of magnetic flux provides a low-cost switching power converter via primary-side control using a primary-side winding. An integrator generates a voltage representing magnetic flux within a power magnetic element by integrating a voltage on a primary-side winding of the power magnetic element. A detection circuit detects the end of a half-cycle of post-conduction resonance in the power magnetic element after the energy level in the power magnetic element reaches zero. The voltage of the integrator is stored at the end of the post-conduction resonance half-cycle and is used to determine a sampling point prior to or equal to the start of post-conduction resonance in a subsequent switching cycle of the power converter. The primary-side winding voltage is then sampled at the sampling point, providing an indication of the output voltage of the power converter.
    Type: Application
    Filed: October 2, 2003
    Publication date: December 30, 2004
    Inventors: Alexander Mednik, David Chalmers Schie, James Hung Nguyen, Wei Gu
  • Patent number: 6781351
    Abstract: AC/DC cascaded power converters having high DC conversion ratio and improved AC line harmonics provide low input harmonic currents, high power factor and efficient operation for low voltage DC outputs when coupled directly to a source of unfiltered rectified AC voltage. The power converter incorporates an intermediate storage element that provides most or all of the energy storage capacitance within the power converter and a blocking device that enables continuous energy transfer from AC line to output to achieve unity power factor and regulated output while maintaining low AC input current ripple.
    Type: Grant
    Filed: October 28, 2002
    Date of Patent: August 24, 2004
    Assignee: Supertex Inc.
    Inventors: Alexander Mednik, David Chalmers Schie, Wei Gu
  • Patent number: 6771679
    Abstract: An apparatus and method for programmable control of laser diode modulation and operating point provides control for laser diodes having widely varying characteristics, such as laser diodes from a variety of manufacturers. Operating a wide variety of lasers is useful for implementation of a device independent integrated circuit for control of a laser diode. Laser diode maximum AC drive levels, AC input circuit response and DC operating point are programmed via a programmable storage coupled via control circuits to a drive amplifier and a bias circuit. The laser diode modulation control may be combined with laser diode bias control in a single integrated circuit, providing a single-chip solution for laser diode transceiver module manufacturers. The programmable storage may be one-time programmable for factory customization of laser diode transceiver module diodes, or may be an electrically alterable storage.
    Type: Grant
    Filed: May 16, 2001
    Date of Patent: August 3, 2004
    Inventor: David Chalmers Schie
  • Publication number: 20040105283
    Abstract: A switch state controller generating a pulse train is used in a power converter utilizing a plurality of converter stages all simultaneously controlled by a single switch controlled by said pulse train. On time of the pulse train is controlled according to an input or interim node characteristic of the supply and period is controlled by a characteristic of the output of the converter. This allows development of AC-to-DC converters, including power-factor-correction converters, and DC to DC converters with high conversion ratio with minimal parts count & high reliability.
    Type: Application
    Filed: August 22, 2003
    Publication date: June 3, 2004
    Inventors: David Chalmers Schie, Alexander Mednik, James Hung Nguyen, Sang Ton Ngo, Khai Minh Le, Wei Gu, Ladislas G. Kerenyi
  • Publication number: 20040079953
    Abstract: AC/DC cascaded power converters having high DC conversion ratio and improved AC line harmonics provide low input harmonic currents, high power factor and efficient operation for low voltage DC outputs when coupled directly to a source of unfiltered rectified AC voltage. The power converter incorporates an intermediate storage element that provides most or all of the energy storage capacitance within the power converter and a blocking device that enables continuous energy transfer from AC line to output to achieve unity power factor and regulated output while maintaining low AC input current ripple.
    Type: Application
    Filed: October 28, 2002
    Publication date: April 29, 2004
    Inventors: Alexander Mednik, David Chalmers Schie, Wei Gu
  • Publication number: 20020166073
    Abstract: An apparatus and method for adaptively controlling power supplied to a hot-pluggable subsystem controls the inrush current of the hot-pluggable subsystem when the subsystem is coupled to another system that supplies power, and optionally other signal connections. The apparatus and method adaptively control a pass device by detecting the voltage at the gate of the pass device during initial charging of the gate. The gate voltage may be sampled and used subsequently to control the operation of the pass device, and short-circuit conditions may be detected by determining that the miller effect does not change the charging of the gate capacitance. Automatic restart circuitry can be included to generate multiple startup attempts, and under-voltage lockout circuitry and power-on-reset timers can be used to provide a robust solution. The apparatus and method can be adapted to provide a three terminal device that does not require a feedback connection from a power supply output.
    Type: Application
    Filed: May 2, 2001
    Publication date: November 7, 2002
    Inventors: James Hung Nguyen, Sang Ton Ngo, David Chalmers Schie, Ladislas G. Kerenyi, Khai Minh Le