Patents by Inventor Raoji A. Patel
Raoji A. Patel 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).
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Patent number: 7502699Abstract: A system and method for determining power use in a system are disclosed. Briefly described, one embodiment of a method comprises metering power flow into a metered front end rectifier system using a metering circuit residing in the metered front end rectifier system and coupled to an alternating current (AC) power source, determining information corresponding to the metered power flow and communicating the determined metered power flow information to a user interface.Type: GrantFiled: July 29, 2005Date of Patent: March 10, 2009Assignee: Hewlett-Packard Development Company, L.P.Inventors: Robert A. Guenther, Raoji Patel
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Patent number: 7193410Abstract: A monitor system and method are described for sensing voltage changes in a plurality of transistors of a multiphase circuit comprising a sensor connected to each one of the plurality of transistors for measuring a voltage drop across the each one, a difference detector for comparing the voltage drop to a previous voltage drop attributable to the each one of the plurality of transistors, and a driver circuit for controlling a state of the plurality of transistors, wherein the driver circuit deactivates one or more of the plurality of transistors when the voltage drop varies from the previous voltage drop by a predefined amount.Type: GrantFiled: May 4, 2004Date of Patent: March 20, 2007Assignee: Hewlett-Packard Development Company, L.P.Inventors: Raoji A. Patel, Robert A. Guenther
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Publication number: 20070027645Abstract: A system and method for determining power use in a system are disclosed. Briefly described, one embodiment of a method comprises metering power flow into a metered front end rectifier system using a metering circuit residing in the metered front end rectifier system and coupled to an alternating current (AC) power source, determining information corresponding to the metered power flow and communicating the determined metered power flow information to a user interface.Type: ApplicationFiled: July 29, 2005Publication date: February 1, 2007Inventors: Robert Guenther, Raoji Patel
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Publication number: 20060220463Abstract: In a computer system having redundant removable power supply modules, a power supply module comprises a voltage output and a signal input. At the voltage output, a voltage is supplied to components of the computer system. At the signal input, a module present signal is received from another power supply module. When the module present signal received from the other power supply module is asserted, the voltage is supplied at a nominal voltage. Upon deassertion of the module present signal received from the other power supply module, the voltage is increased to a maximum voltage.Type: ApplicationFiled: April 4, 2005Publication date: October 5, 2006Inventors: Raoji Patel, Robert Guenther
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Publication number: 20050248360Abstract: A monitor system and method are described for sensing voltage changes in a plurality of transistors of a multiphase circuit comprising a sensor connected to each one of the plurality of transistors for measuring a voltage drop across the each one, a difference detector for comparing the voltage drop to a previous voltage drop attributable to the each one of the plurality of transistors, and a driver circuit for controlling a state of the plurality of transistors, wherein the driver circuit deactivates one or more of the plurality of transistors when the voltage drop varies from the previous voltage drop by a predefined amount.Type: ApplicationFiled: May 4, 2004Publication date: November 10, 2005Inventors: Raoji Patel, Robert Guenther
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Publication number: 20050094330Abstract: Systems, methodologies, components, and other embodiments associated with converting power and bus architectures are described. One exemplary system embodiment comprises a first set of power converters configured to convert a received input power level to one or more power levels, and a second set of power converters. An interleaved intermediate bus is configured to supply independent and redundant input to the second set of power converters from the one or more output power levels of the first set of power converters.Type: ApplicationFiled: November 5, 2003Publication date: May 5, 2005Inventors: Robert Guenther, Raoji Patel
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Patent number: 6831544Abstract: A method and apparatus to layout planar magnetic coils on a PCB consists of maximizing the layer to layer overlap, and consequently maximizing total inductance for the given layout area, by spiraling alternating layers inward and outward. A further benefit of the matching opposite spirals is the ability to make the layer to layer electrical contacts within the magnetic field area, thus reducing leakage inductance, and minimizing the wasted extra conductor line length needed to make the connections outside the magnetic field. The reduced conductor line length results in reduced conductor line resistance. The method is applicable to voltage transformers and isolation transformers as well as simple inductors and other magnetic devices. In the transformer case the odd numbered layers are typically connected together in series to provide a larger turn ratio, and the even numbered layers are typically single turns (i.e., no spiral) connected together in parallel to provide more current capability.Type: GrantFiled: October 9, 2003Date of Patent: December 14, 2004Assignee: Hewlett-Packard Development Company, L.P.Inventors: Raoji A. Patel, James E. Drew, Raymond A. Pelletier, Brian R. McQuain
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Publication number: 20040070481Abstract: A method and apparatus to layout planar magnetic coils on a PCB consists of maximizing the layer to layer overlap, and consequently maximizing total inductance for the given layout area, by spiraling alternating layers inward and outward. A further benefit of the matching opposite spirals is the ability to make the layer to layer electrical contacts within the magnetic field area, thus reducing leakage inductance, and minimizing the wasted extra conductor line length needed to make the connections outside the magnetic field. The reduced conductor line length results in reduced conductor line resistance. The method is applicable to voltage transformers and isolation transformers as well as simple inductors and other magnetic devices. In the transformer case the odd numbered layers are typically connected together in series to provide a larger turn ratio, and the even numbered layers are typically single turns (i.e., no spiral) connected together in parallel to provide more current capability.Type: ApplicationFiled: October 9, 2003Publication date: April 15, 2004Inventors: Raoji A. Patel, James E. Drew, Raymond A. Pelletier, Brian R. McQuain
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Patent number: 6664883Abstract: A method and apparatus to layout planar magnetic coils on a PCB consists of maximizing the layer to layer overlap, and consequently maximizing total inductance for the given layout area, by spiraling alternating layers inward and outward. A further benefit of the matching opposite spirals is the ability to make the layer to layer electrical contacts within the magnetic field area, thus reducing leakage inductance, and minimizing the wasted extra conductor line length needed to make the connections outside the magnetic field. The reduced conductor line length results in reduced conductor line resistance. The method is applicable to voltage transformers and isolation transformers as well as simple inductors and other magnetic devices. In the transformer case the odd numbered layers are typically connected together in series to provide a larger turn ratio, and the even numbered layers are typically single turns (i.e., no spiral) connected together in parallel to provide more current capability.Type: GrantFiled: June 11, 2002Date of Patent: December 16, 2003Assignee: Hewlett-Packard Development Company, L.P.Inventors: Raoji A. Patel, James E. Drew, Raymond A. Pelletier, Brian R. McQuain
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Patent number: 6600668Abstract: A crowbar circuit comprises an over-voltage detector that monitors the output voltage of a synchronous DC/DC converter. When the output voltage rises above a predetermined threshold, the detector applies a control signal to a MOSFET switch that is already in use as part of a rectifier in the converter. The control signal overrides a periodic switching signal applied to the gate of the MOSFET, causing it to conduct continuously and thereby apply a shunt path for the output current of the rectifier. The control signal may be continuously applied until the converter is manually reset. Because the voltage across the conducting MOSFET is small and it can be turned on quickly, the MOSFET rapidly clamps the DC/DC converter's output to a voltage low enough to avoid damage to integrated circuitry powered by the converter.Type: GrantFiled: May 21, 2002Date of Patent: July 29, 2003Assignee: Hewlett-Packard Development Company, L.P.Inventors: Raoji A. Patel, Raymond A. Pelletier
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Patent number: 6565382Abstract: A core mounting assembly includes a printed wiring board having a substrate with opposite sides, a winding on one side and a plurality of through holes extending through the substrate adjacent to the winding. A pair of mirror-image core sections are positioned against the sides of the board opposite the first winding, the core sections having corresponding portions which project into the through holes. A bracket has a back portion engaging one of the core sections and at least two legs extending from the back portion through two of the through holes in the board. A resilient cover member has a first end releasably secured to one of the legs, a second end releasably secured to the other of the legs and a bridging portion extending between the first and second ends and pressing against the other of the core sections so as to bias the core sections together.Type: GrantFiled: December 7, 2001Date of Patent: May 20, 2003Assignee: Hewelett-Packard Development Company, L.P.Inventors: William M. Blodgett, Richard E. Olson, Raoji A. Patel
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Publication number: 20020149461Abstract: A method and apparatus to layout planar magnetic coils on a PCB consists of maximizing the layer to layer overlap, and consequently maximizing total inductance for the given layout area, by spiraling alternating layers inward and outward. A further benefit of the matching opposite spirals is the ability to make the layer to layer electrical contacts within the magnetic field area, thus reducing leakage inductance, and minimizing the wasted extra conductor line length needed to make the connections outside the magnetic field. The reduced conductor line length results in reduced conductor line resistance. The method is applicable to voltage transformers and isolation transformers as well as simple inductors and other magnetic devices. In the transformer case the odd numbered layers are typically connected together in series to provide a larger turn ratio, and the even numbered layers are typically single turns (i.e., no spiral) connected together in parallel to provide more current capability.Type: ApplicationFiled: June 11, 2002Publication date: October 17, 2002Applicant: Compaq Computer CorporationInventors: Raoji A. Patel, James E. Drew, Raymond A. Pelletier, Brian R. McQuain
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Patent number: 6456510Abstract: A regulated power supply in which square wave output of a switching rectifier is applied to a filter comprises a series inductor and a parallel capacitor. This filter lacks a series resistor. The ramp signal is developed across a second capacitor in series with a first resistor, and in parallel with the rectifier output. An amplifier adds the ramp signal to a signal representing the error in the DC output voltage of the power supply, producing an output that is fed to a control circuit. The control circuit in response generates a voltage control signal that controls the switching of the rectifier.Type: GrantFiled: August 31, 2000Date of Patent: September 24, 2002Assignee: Compaq Computer CorporationInventors: Raoji Patel, Robert Wolf
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Patent number: 6429763Abstract: A method and apparatus to layout planar magnetic coils on a PCB consists of maximizing the layer to layer overlap, and consequently maximizing total inductance for the given layout area, by spiraling alternating layers inward and outward. A further benefit of the matching opposite spirals is the ability to make the layer to layer electrical contacts within the magnetic field area, thus reducing leakage inductance, and minimizing the wasted extra conductor line length needed to make the connections outside the magnetic field. The reduced conductor line length results in reduced conductor line resistance. The method is applicable to voltage transformers and isolation transformers as well as simple inductors and other magnetic devices. In the transformer case the odd numbered layers are typically connected together in series to provide a larger turn ratio, and the even numbered layers are typically single turns (i.e., no spiral) connected together in parallel to provide more current capability.Type: GrantFiled: February 1, 2000Date of Patent: August 6, 2002Assignee: Compaq Information Technologies Group, L.P.Inventors: Raoji A. Patel, James E. Drew, Raymond A. Pelletier, Brian R. McQuain
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Publication number: 20020057171Abstract: A method and apparatus to layout planar magnetic coils on a PCB consists of maximizing the layer to layer overlap, and consequently maximizing total inductance for the given layout area, by spiraling alternating layers inward and outward. A further benefit of the matching opposite spirals is the ability to make the layer to layer electrical contacts within the magnetic field area, thus reducing leakage inductance, and minimizing the wasted extra conductor line length needed to make the connections outside the magnetic field. The reduced conductor line length results in reduced conductor line resistance. The method is applicable to voltage transformers and isolation transformers as well as simple inductors and other magnetic devices. In the transformer case the odd numbered layers are typically connected together in series to provide a larger turn ratio, and the even numbered layers are typically single turns (i.e., no spiral) connected together in parallel to provide more current capability.Type: ApplicationFiled: February 1, 2000Publication date: May 16, 2002Inventors: Raoji A. Patel, James E. Drew, Raymond A. Pelletier, Brian R. McQuain
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Patent number: 6373732Abstract: A method of preventing current hogging in parallel connected transformers, and an apparatus for efficiently implementing the method are presented. Current hogging occurs when synchronous power converter transformers operate in a low output current mode. Low output current demands are typically meet by adjusting the duty cycle of the transformer to a low level. This results in the catch FET maintaining a low resistance path to ground for long time periods and allows a stronger one of the parallel power converter transformers to sink current to ground through a weaker transformer. The method consists of using a current sensor to detect low or negative output currents, and then driving the transistor providing the path to ground to an off state.Type: GrantFiled: February 1, 2000Date of Patent: April 16, 2002Assignee: Compaq Information Technologies Group, L.P.Inventors: Raoji A. Patel, Raymond A. Pelletier, Robert J. Wolf
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Patent number: 5305185Abstract: There is provided a method and materials for cooling the power train components, such as transformers, rectifiers, chokes, and the like, of an integrated on-board power supply IOP) using a single heatsink. Spacers are positioned between the power train components and a substrate, the substrate for mounting the components. The spacers are individually dimensioned and shaped to raise the heat-removal surfaces of the components to a substantially uniform and minimal height. A heatsink having a substantially planar, heat-acquiring surface is positioned on the heat-removal surfaces of the power train components. Fasteners are used to compress the spacers, urging the components against the heatsink to provide a substantially continuous and coplanar thermal interface between the components and the heatsink. After the components, heat sink and substrate have been fastened to each other, the components are electrically connected to the substrate by soldering.Type: GrantFiled: September 30, 1992Date of Patent: April 19, 1994Inventors: Victor M. Samarov, Joseph A. DeCarolis, Raoji Patel, Gerald J. Piche, Glenn R. Skutt, Steve W. Norris
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Patent number: 4716514Abstract: A synchronous power rectifier incorporating a bipolar power transistor operable in a switching mode to rectify the energy from a secondary winding of a power transformer. The synchronous rectifier reduces or eliminates the need of rectifier diodes, which provides power rectification without the power loss associated with the rectifier diode voltage drops. Moreover, the present invention includes further refinements of the circuit, including adjustment of the rectifier switching time to accommodate delayed turn-off times of bipolar power devices, and adjustment of the switching signal duration to provide output voltage regulation independent of the excitation of the transformer primary. The resulting embodiments of the present invention provide a modular switching power supply circuit of high efficiency, which may be operable together in combination to provide multiple output voltages.Type: GrantFiled: September 22, 1986Date of Patent: December 29, 1987Assignee: Unitrode CorporationInventor: Raoji Patel