Patents by Inventor Vivek Mehrotra

Vivek Mehrotra 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: 7280026
    Abstract: A matrix integrated magnetics (MIM) “Extended E” core in which a plurality of outer legs are disposed on a base and separated along a first outer edge to define windows therebetween. A center leg is disposed on the top region of the base and separated from the outer legs to define a center window. The center leg is suitably positioned along a second outer edge opposite the first or between outer legs positioned along opposing outer edges. A plate is disposed on the outer legs opposite the base.
    Type: Grant
    Filed: August 19, 2004
    Date of Patent: October 9, 2007
    Assignee: ColdWatt, Inc.
    Inventors: Sriram Chandrasekaran, Vivek Mehrotra
  • Publication number: 20060187684
    Abstract: A power converter having input and output nodes and a method of operating the same. In one embodiment, the power converter includes a switching circuit including first, second and third active phase legs. Each of the first, second and third active legs includes a first switch coupled to one of the input nodes and a second switch coupled to another of the input nodes and has a common switching node therebetween. The power converter further includes a magnetic device including first, second and third primary windings, and first, second and third secondary windings. The first, second and third primary windings are coupled to the common switching node of the first, second and third active phase legs, respectively. The power converter still further includes a rectifier including first, second and third rectifier elements interposed between the first, second and third secondary windings, respectively, and one of the output nodes.
    Type: Application
    Filed: February 8, 2006
    Publication date: August 24, 2006
    Inventors: Sriram Chandrasekaran, Vivek Mehrotra
  • Publication number: 20060151871
    Abstract: A method of forming packages containing SiC or other semiconductor devices bonded to other components or conductive surfaces utilizing transient liquid phase (TLP) bonding to create high temperature melting point bonds using in situ formed ternary or quaternary mixtures of conductive metals and the devices created using TLP bonds of ternary or quaternary materials. The compositions meet the conflicting requirements of an interconnect or joint that can be exposed to high temperature, and is thermally and electrically conductive, void and creep resistant, corrosion resistant, and reliable upon temperature and power cycling.
    Type: Application
    Filed: January 7, 2005
    Publication date: July 13, 2006
    Inventor: Vivek Mehrotra
  • Patent number: 7046523
    Abstract: There is disclosed a core structure with a very low profile, high power density and lower losses. The disclosed design allows for a larger core area where the DC fluxes are added, thereby reducing the air-gap requirements in the cores derived from low saturation density materials such as ferrites. The cellular nature of the design can be effectively employed in vertically packaged power converters and modules. Also disclosed is a DC-DC converter topology which preferably employs the disclosed core. N AC drive voltages drive N current doubler rectifiers (CDRs) in accordance with the symmetric modulation scheme; each CDR provides two rectified output currents to an output node. Each AC drive voltage has a switching period Ts. The drive voltages are phase-shifted by Ts/(2*N), such that the rectified output currents of the CDRs are interleaved, thereby reducing output voltage ripple.
    Type: Grant
    Filed: November 21, 2002
    Date of Patent: May 16, 2006
    Assignee: ColdWatt, Inc.
    Inventors: Jian Sun, Xiukuan Jing, Sriram Chandrasekaran, Vivek Mehrotra
  • Patent number: 7012414
    Abstract: A vertically packaged cellular power converter solves the problems associated with conventional designs and paves the way for a cellular circuit architecture with ultra-low interconnect resistance and inductance. The vertical packaging results in a power flow in the vertical direction (from the bottom to the top) with very short internal interconnects, thereby minimizing the associated conduction losses and permitting high conversion efficiency at high currents. The cellular architecture is ideally suited for generating multiple supply voltages.
    Type: Grant
    Filed: August 19, 2004
    Date of Patent: March 14, 2006
    Assignee: ColdWatt, Inc.
    Inventors: Vivek Mehrotra, Jian Sun, Sriram Chandrasekaran
  • Publication number: 20060038649
    Abstract: Cutout and/or keep away regions are etched in the winding structure near the gapped center leg of a magnetic core. This reduces eddy current losses caused by the leakage field and improves current uniformity and current sharing between windings thereby increasing converter efficiency. Windings closest to the air gap are suitably formed with both keep away regions and cutouts. Windings a little further away are formed with only cutouts and the windings furthest away are unchanged. This approach keeps the net winding losses low in the presence of a fringing field. The precise configuration is determined by the core structure, air gap and winding arrangements.
    Type: Application
    Filed: August 19, 2004
    Publication date: February 23, 2006
    Inventors: Vivek Mehrotra, Jian Sun
  • Publication number: 20060038549
    Abstract: A vertically packaged cellular power converter solves the problems associated with conventional designs and paves the way for a cellular circuit architecture with ultra-low interconnect resistance and inductance. The vertical packaging results in a power flow in the vertical direction (from the bottom to the top) with very short internal interconnects, thereby minimizing the associated conduction losses and permitting high conversion efficiency at high currents. The cellular architecture is ideally suited for generating multiple supply voltages.
    Type: Application
    Filed: August 19, 2004
    Publication date: February 23, 2006
    Inventors: Vivek Mehrotra, Jian Sun, Sriram Chandrasekaran
  • Publication number: 20060038650
    Abstract: A vertical winding structure for planar integrated magnetics used in switched-mode power converters maintains close coupling between the different windings but reduces the eddy current losses, lowers the DC winding resistance and reduces the number of layers of the PCB. Vertical and horizontal windings can be used together without sacrificing these performance advantages and further minimizing the capacitive coupling between the outer-leg windings and the center-leg winding. This winding structure can be used in a wide range of magnetic structures including isolated and non-isolated CDRs, interleaved CDRs, and buck and boost converters.
    Type: Application
    Filed: August 19, 2004
    Publication date: February 23, 2006
    Inventors: Vivek Mehrotra, Jian Sun, Sriram Chandrasekaran
  • Patent number: 6980077
    Abstract: A composite magnetic core formed of a high permeability material and a lower permeability, high saturation flux density material prevents core saturation without an air gap and reduces eddy current losses and loss of inductance. The composite core is configured such that the low permeability, high saturation material is located where the flux accumulates from the high permeability sections. The presence of magnetic material having a relatively high permeability keeps the flux confined within the core thereby preventing fringing flux from spilling out into the winding arrangement. This composite core configuration balances the requirements of preventing core saturation and minimizing eddy current losses without increasing either the height or width of the core or the number of windings.
    Type: Grant
    Filed: August 19, 2004
    Date of Patent: December 27, 2005
    Assignee: ColdWatt, Inc.
    Inventors: Sriram Chandrasekaran, Vivek Mehrotra, Jian Sun
  • Publication number: 20050245658
    Abstract: A method of forming nano composites within a polymer structure comprises exposing a wettable polymer having ion-exchangeable groups pendant therefrom to an aqueous solution of a soluble salt containing metal ions, the metal ions replacing, by ion exchange, the pendant groups on the polymer. After ion exchange the polymer is exposed to a reducing agent forming metal oxides trapped within the polymer structure.
    Type: Application
    Filed: April 30, 2004
    Publication date: November 3, 2005
    Inventors: Vivek Mehrotra, Ira Goldberg
  • Patent number: 6873237
    Abstract: There is disclosed a core structure with a very low profile, high power density and lower losses. Higher core surface area and improved core utilization in terms of flux density are other desirable feature in the disclosed design. The disclosed design also allowed for a larger core area where the DC fluxes are added, thereby reducing the air-gap requirements in the cores derived from low saturation density materials such as ferrites. The cellular nature of the design can also be effectively employed in vertically packaged power converters and modules.
    Type: Grant
    Filed: April 18, 2002
    Date of Patent: March 29, 2005
    Assignee: Innovative Technology Licensing, LLC
    Inventors: Sriram Chandrasekaran, Vivek Mehrotra, Jian Sun
  • Publication number: 20050024179
    Abstract: A matrix integrated magnetics (MIM) “Extended E” core in which a plurality of outer legs are disposed on a base and separated along a first outer edge to define windows there between. A center leg is disposed on the top region of the base and separated from the outer legs to define a center window. The center leg is suitably positioned along a second outer edge opposite the first or between outer legs positioned along opposing outer edges. A plate is disposed on the outer legs opposite the base.
    Type: Application
    Filed: August 19, 2004
    Publication date: February 3, 2005
    Inventors: Sriram Chandrasekaran, Vivek Mehrotra
  • Publication number: 20030197585
    Abstract: There is disclosed a core structure with a very low profile, high power density and lower losses. Higher core surface area and improved core utilization in terms of flux density are other desirable feature in the disclosed design. The disclosed design also allowed for a larger core area where the DC fluxes are added, thereby reducing the air-gap requirements in the cores derived from low saturation density materials such as ferrites. The cellular nature of the design can also be effectively employed in vertically packaged power converters and modules.
    Type: Application
    Filed: April 18, 2002
    Publication date: October 23, 2003
    Applicant: INNOVATIVE TECHNOLOGY LICENSING, LLC
    Inventors: Sriram Chandrasekaran, Vivek Mehrotra, Jian Sun
  • Publication number: 20030198067
    Abstract: There is disclosed a core structure with a very low profile, high power density and lower losses. The disclosed design allows for a larger core area where the DC fluxes are added, thereby reducing the air-gap requirements in the cores derived from low saturation density materials such as ferrites. The cellular nature of the design can be effectively employed in vertically packaged power converters and modules. Also disclosed is a DC-DC converter topology which preferably employs the disclosed core. N AC drive voltages drive N current doubler rectifiers (CDRs) in accordance with the symmetric modulation scheme; each CDR provides two rectified output currents to an output node. Each AC drive voltage has a switching period Ts. The drive voltages are phase-shifted by Ts/(2*N), such that the rectified output currents of the CDRs are interleaved, thereby reducing output voltage ripple.
    Type: Application
    Filed: November 21, 2002
    Publication date: October 23, 2003
    Applicant: Innovative Technology Licensing, LLC
    Inventors: Jian Sun, Xiukuan Jing, Sriram Chandrasekaran, Vivek Mehrotra
  • Patent number: 6353295
    Abstract: A lamp electronic ballast with a piezoelectric cooling fan. Use of ballast-driven lamps is limited in some lighting applications by thermal considerations. For example, the problem of heat removal from compact fluorescent lamps with integrated ballasts has limited their use. Similarly, the use of ballast-driven fluorescent lighting in high hat and other closed luminaire applications has been limited by thermal considerations. Thermal management of ballasts for such thermally sensitive applications is provided by a piezoelectric fan integrated with the ballast. The power to drive the fan may be obtained from the same AC line input that supplies the ballast, or from an AC ripple voltage present at the output of a rectifier in the ballast, or from the output of the ballast to the lamp, or from any suitable circuit location in the ballast. The fan maybe a membrane-type spot-cooler comprising a thin membrane carried by a frame mounted adjacent a hot spot.
    Type: Grant
    Filed: January 20, 1999
    Date of Patent: March 5, 2002
    Assignee: Philips Electronics North America Corporation
    Inventors: Shri Sridhar, Vivek Mehrotra, Juan Sabate, Gert W. Bruning, Nicolaas Bernardus Roozen
  • Patent number: 6342753
    Abstract: A piezoelectric transformer has pairs of input/output electrodes located on a piezoelectric body corresponding to period locations on a standing sine wave superimposed on said body, and having a waveform corresponding to vibrational modes of the piezoelectric body at resonance. The transformer also has a grounded guard electrodes to reduce parasitic coupling between its input and output regions.
    Type: Grant
    Filed: September 25, 2000
    Date of Patent: January 29, 2002
    Assignee: Rockwell Technologies, LLC
    Inventors: John Oliver, Vivek Mehrotra, R. R. Neurgaonkar
  • Patent number: 6118651
    Abstract: Anodized aluminum anode and cathode foils are interleaved in a stack separated by spacers saturated with electrolyte in an enclosure. The anode foils and cathode foils have tabs which protrude from the housing and are cold welded to leads outside the housing, where they are not exposed to electrolyte. This permits using copper leads, which can be soldered to traces on a printed circuit board. A flat capacitor can be fixed underneath a PCB or even used as the substrate for a circuit, resulting in high volume efficiencies and the possibility of using it as a heat sink for other components.
    Type: Grant
    Filed: December 24, 1997
    Date of Patent: September 12, 2000
    Assignee: Philips Electronics North America Corp.
    Inventors: Vivek Mehrotra, Jose Azevedo, Shri Sridhar
  • Patent number: 6037714
    Abstract: Novel emitter materials, electrode assemblies amd lamps comprising the same are provided in which, in accordance with the invention, novel electrodes are provided having a lamp electrode structure, preferably including a hollow ferrule for sealing in a lamp to permit evacuation; an emitter material of the invention on at least one surface thereof, preferably on a protrusion attached to the hollow ferrule; a thermal isolator, preferably in the form of a low thermal conductivity wire or an incised or cut-out portion of the hollow ferrule body, for thermally isolating the protrusion from the ferrule to maintain a sufficiently high temperature for thermionic emission, and further comprising an emitter material requiring no in-lamp processing. The emitter materials are a mixed oxide of Ba, Sr and mixtures thereof with one or more of the metals from the series comprising Ta, Ti, Zr, Sc, Y, and La, are preferably selected from the group consisting of Ba.sub.4 Ta.sub.2 O.sub.9, Ba.sub.5 Ta.sub.4 O.sub.15, BaY.sub.
    Type: Grant
    Filed: December 29, 1995
    Date of Patent: March 14, 2000
    Assignee: Philips Electronics North America Corporation
    Inventors: Vivek Mehrotra, Thomas F. McGee, Susan McGee, Jeroen Langevoort, Edward Young
  • Patent number: 6007399
    Abstract: To improve performance, reliability and lifetime of a plasma-containing electro-optic display device, at least the cathode electrodes have hollows or wells within which plasma discharge occurs. This reduces the tendency of the electrode material to be sputter deposited on the walls of the device. In addition, cathode emission is improved by incorporating emitter materials into the electrodes, either by alloying or by surface coatings.
    Type: Grant
    Filed: March 23, 1999
    Date of Patent: December 28, 1999
    Assignee: Philips Electronics North America Corporation
    Inventors: Vivek Mehrotra, Babar A. Khan
  • Patent number: 5982097
    Abstract: Novel emitter materials, electrode assemblies amd lamps comprisinfg the same are provided in which, in accordance with the invention, novel electrodes are provided having a lamp electrode structure, preferably including a hollow ferrule for sealing in a lamp to permit evacuation; an emitter material of the invention on at least one surface thereof, preferably on a protrusion attached to the hollow ferrule; a thermal isolator, preferably in the form of a low thermal conductivity wire or an incised or cut-out portion of the hollow ferrule body, for thermally isolating the protrusion from the ferrule to maintain a sufficiently high temperature for thermionic emission, and further comprising an emitter material requiring no in-lamp processing. The emitter materials are a mixed oxide of Ba, Sr and mixtures thereof with one or more of the metals from the series comprising Ta, Ti, Zr, Sc, Y, and La, are preferably selected from the group consisting of Ba.sub.4 Ta.sub.2 O.sub.9, Ba.sub.5 Ta.sub.4 O.sub.15, BaY.sub.
    Type: Grant
    Filed: December 29, 1995
    Date of Patent: November 9, 1999
    Assignee: Philips Electronics North America Corporation
    Inventors: Vivek Mehrotra, Thomas F. McGee, Susan McGee, Jeroen Langevoort, Edward Young