POWER electronics

Nov 1, 2009 12:00 PM
SAM DAVIS, Editor in Chief

COMMON-MODE NOISE REDUCTION USING PARASITIC CAPACITANCE CANCELLATION

Issued October 13, 2009
United States Patent 7,602,159

A negative capacitance is developed by configuring an inductor as two inversely coupled windings having different numbers of turns, and connecting a capacitance to a center tap between the two windings. Negative capacitance is developed on the side of the inductor having the winding with the greater number of turns. The negative capacitance so developed may advantageously be used to cancel any capacitance or parasitic capacitance desired for reducing power loss, increasing switching speed, or reducing or eliminating common-mode noise in a switched circuit, such as a switched power converter.

Inventors: Wang, Shuo (Blacksburg, VA); Lee, Fred C. (Blacksburg, VA)

Assignee: Virginia Tech Intellectual Properties, Inc. (Blacksburg, VA)

Appl. No.: 11/678,864

Filed: February 26, 2007

COUPLED INDUCTOR OUTPUT REGULATION

Issued October 13, 2009
United States Patent 7,602,163

An information handling system includes a power converter having a first switched inductor to supply current to a load. A second switched inductor is inductively coupled to the first switched inductor. A control circuit activates the second switched inductor in response to a change in the power requirements of the load, so as to remove energy stored in the first switched inductor and thereby regulate the output voltage of the power converter when load current is stepped downwards.

Inventors: Johnson, Brian Patrick (Cedar Park, TX); Jenkins, Daniel E. (Bastrop, TX)

Assignee: Dell Products L.P. (Round Rock, TX)

Appl. No.: 11/313,343

Filed: December 20, 2005

INTEGRATED POWER SUPPLY FOR SURFACE COILS

Issued October 13, 2009
United States Patent 7,602,187

An RF receive coil for receiving a magnetic resonance (MR) signal includes an RF antenna. The RF antenna includes one or more electrical conductors, at least one of which is a substantially hollow conductor. At least one electrical component is mounted to be shielded from interfering with the MR signal by disposing it inside the substantially hollow conductor. At least one electrical component can be, for example, a battery, a storage capacitor, or coil electronics.

Inventors: Luedeke, Kai-Michael (Hamburg, DE); Findeklee, Christian (Hamburg, DE); Notten, Peter H. (Eindhoven, NL); van Helvoort, Marinus J. A. M. (Best, NL); Tuithof, Hans H. (Best, NL)

Assignee: Koninklijke Philips Electronics N.V. (Eindhoven, NL)

Appl. No.: 11/570,893

Filed: June 7, 2005

HALF-BRIDGE CIRCUITS WITH NORMALLY ON SWITCHES AND PREVENTING UNINTENDED CURRENT FLOW

Issued October 13, 2009
United States Patent 7,602,228

A method for rendering a half-bridge circuit containing normally on switches — such as JFETs — inherently safe from uncontrolled current flow is described. The switches can be made from silicon carbide or from silicon. The methods described allow for the use of better-performing normally on switches in place of normally off switches in IPMs, thereby improving the efficiency, size, weight, and cost of the IPMs. As described herein, a power supply can be added to the gate driver circuitry. The power supply can be self starting and self oscillating while being capable of deriving all of its source energy from the terminals supplying electrical potential to the normally on switch through the gate driver. The terminal characteristics of the normally on switch can then be coordinated to the input-to-output characteristics of the power supply.

Inventors: Mazzola, Michael S. (Starkville, MS); Kelley, Robin L. (Columbus, MS)

Assignee: SemiSouth Laboratories, Inc. (Starkville, MS)

Appl. No.: 11/802,388

Filed: May 22, 2007

HIGH-FREQUENCY CONTROL OF A SEMICONDUCTOR SWITCH

Issued October 13, 2009
United States Patent 7,602,229

Resonant gate-driver circuits provide for efficient switching of, for example, a MOSFET. However, often an operation of the gate-driver circuit does not allow for an application where high switching frequencies are required. According to the present invention, pre-charging of the inductor of the resonant gate driver circuit allows for highly efficient and fast operation of the MOSFETs.

Inventors: Tolle, Tobias Georg (Turnhout, DE); Durbaum, Thomas (Baiersdorf, DE); Sauerlander, Georg (Aachen, DE); Lopez; Toni (Aachen, DE)

Assignee: Koninklijke Philips Electronics N.V. (Eindhoven, NL)

Appl. No.: 10/570,743

Filed: August 25, 2004

LUMINANCE SUPPRESSION POWER CONSERVATION

Issued October 13, 2009
United States Patent 7,602,408

Described herein are systems and methods to reduce power consumption for electronic devices. The systems and methods alter video information in a display area and reduce power for a display device when a graphics item is enlarged. The enlargement threatens to increase perceived luminance for the graphics item or increase aggregate luminance for the display area. Altering video information reduces the luminance of video information in at least the graphics item when enlarged. This may offset perceived luminance gained by human visual processing when an item increases in size. If the graphics item is smaller than the display area after enlargement, other video information in the display area may also be altered to conserve power.

Inventors: Plut, William J. (Menlo Park, CA)

Assignee: Honeywood Technologies, LLC (Menlo Park, CA)

Appl. No.: 11/122,318

Filed: May 4, 2005

POWER SUPPLY PROVIDES ULTRAFAST MODULATION OF OUTPUT VOLTAGE

Issued October 13, 2009
United States Patent 7,602,155

A power supply for providing a modulated output voltage to a load is disclosed. The power supply comprises a plurality of parallel-connected switch-mode power modules and a controller. The controller is connected to each power module and controls the duty cycles of the respective power modules, such that the power modules have a common duty cycle in steady state, but in a phase-shifted or interleaved manner. In addition, the controller manages power converter output voltage by controlling the ratio of power modules in the forward state to the total number of power modules.

Inventors: Markowski, Piotr (Worcester, MA)

Assignee: Artesyn Technologies, Inc. (Boca Raton, FL)

Appl. No.: 11/190,642

Filed: July 27, 2005

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