Patents Represented by Attorney Chemily LLC
  • Patent number: 8247297
    Abstract: A method is disclosed for creating a semiconductor device structure with an oxide-filled large deep trench (OFLDT) portion having trench size TCS and trench depth TCD. A bulk semiconductor layer (BSL) is provided with a thickness BSLT>TCD. A large trench top area (LTTA) is mapped out atop BSL with its geometry equal to OFLDT. The LTTA is partitioned into interspersed, complementary interim areas ITA-A and ITA-B. Numerous interim vertical trenches of depth TCD are created into the top BSL surface by removing bulk semiconductor materials corresponding to ITA-B. The remaining bulk semiconductor materials corresponding to ITA-A are converted into oxide. If any residual space is still left between the so-converted ITA-A, the residual space is filled up with oxide deposition. Importantly, the geometry of all ITA-A and ITA-B should be configured simple and small enough to facilitate fast and efficient processes of oxide conversion and oxide filling.
    Type: Grant
    Filed: December 15, 2009
    Date of Patent: August 21, 2012
    Assignee: Alpha & Omega Semiconductor Inc.
    Inventors: Xiaobin Wang, Anup Bhalla, Yeeheng Lee
  • Patent number: 8217748
    Abstract: An inductive power electronics package is disclosed. It has a circuit substrate with power inductor attached atop. The power inductor has inductor core of closed magnetic loop with an interior window. The closed magnetic loop can include air gap for inductance adjustment. The circuit substrate has bottom half-coil forming elements constituting a bottom half-coil beneath the inductor core. Also provided are top half-coil forming elements interconnected with the bottom half-coil forming elements to form an inductive coil enclosing the inductor core. An inner connection chip can be added in the interior window for interconnecting bottom half-coil forming elements with top half-coil forming elements. An outer connection chip can be added about the inductor core for interconnecting bottom half-coil forming elements with top half-coil forming elements outside the inductor core. A power Integrated Circuit can be attached to the top side of the circuit substrate as well.
    Type: Grant
    Filed: March 4, 2009
    Date of Patent: July 10, 2012
    Assignee: Alpha & Omega Semiconductor Inc.
    Inventors: Tao Feng, Xiaotian Zhang, François Hébert, Ming Sun
  • Patent number: 8212329
    Abstract: A short channel Lateral MOSFET (LMOS) and method are disclosed with interpenetrating drain-body protrusions (IDBP) for reducing channel-on resistance while maintaining high punch-through voltage. The LMOS includes lower device bulk layer; upper source and upper drain region both located atop lower device bulk layer; both upper source and upper drain region are in contact with an intervening upper body region atop lower device bulk layer; both upper drain and upper body region are shaped to form a drain-body interface; the drain-body interface has an IDBP structure with a surface drain protrusion lying atop a buried body protrusion while revealing a top body surface area of the upper body region; gate oxide-gate electrode bi-layer disposed atop the upper body region forming an LMOS with a short channel length defined by the horizontal length of the top body surface area delineated between the upper source region and the upper drain region.
    Type: Grant
    Filed: November 6, 2010
    Date of Patent: July 3, 2012
    Assignee: Alpha and Omega Semiconductor Inc.
    Inventors: Shekar Mallikarjunaswamy, Amit Paul
  • Patent number: 8178954
    Abstract: A semiconductor package for power converter application comprises a low-side MOSFET chip and a high-side MOSFET chip stacking one over the other. The semiconductor package may further enclose a capacitor whereas the capacitor may be a discrete component or an integrated component on chip level with the low-side MOSFET. The semiconductor package may further comprise a PIC chip to provide a complete power converter on semiconductor chip assembly package level.
    Type: Grant
    Filed: January 26, 2010
    Date of Patent: May 15, 2012
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yan Xun Xue, Anup Bhalla, Jun Lu
  • Patent number: 7902894
    Abstract: A hysteretic comparator is proposed for comparing input signals and producing an output signal VOT with a hysteresis window Vhys. The hysteretic comparator includes a differential input stage with current output (DICO) having input transistors with transconductance Gmtnx for converting the input signals, with an input stage transconductance Gmin, into intermediate signal currents. A steerable offset current generator, driven by a steering control signal, steers an offset current source IOS to alternative offset currents. A current-to-voltage summing converter (IVSC) sums up the intermediate signal currents and the offset currents and converts the result into VOT plus the steering control signal causing Vhys=IOS/Gmin. A feedback resistance RNF is connected to the input transistors to form a negative feedback loop. The RNF is sized such that GMin, hence Vhys, becomes essentially solely dependent upon the feedback conductance GNF=1/RNF independent of the Gmtnx thus its process and environmental variation.
    Type: Grant
    Filed: June 26, 2009
    Date of Patent: March 8, 2011
    Assignee: Alpha and Omega Semiconductor Inc.
    Inventor: Behzad Mohtashemi
  • Patent number: 7898831
    Abstract: A circuit is proposed for limiting maximum switching FET drain-source voltage (VDS) of a transformer-coupled push pull power converter with maximum DC supply voltage VIN—MAX. Maximum VDS is accentuated by leakage inductances of the push pull transformer and the power converter circuit traces. The limiting circuit bridges the drains of the switching FETs and it includes two serially connected opposing Zener diodes each having a Zener voltage Vzx. The invention is applicable to both N-channel and P-channel FETs. In a specific embodiment, Vzx is selected to be slightly ?2*VIN—MAX with the maximum VDS clamped to about VIN—MAX+½ Vzx. In another embodiment, a proposed power switching device with integrated VDS-clamping includes: a) A switching FET. b) A Zener diode having a first terminal and a second terminal, the second terminal of the Zener diode is connected to the drain terminal of the switching FET.
    Type: Grant
    Filed: May 9, 2008
    Date of Patent: March 1, 2011
    Assignee: Alpha and Omega Semiconductor Inc.
    Inventor: Sanjay Havanur
  • Patent number: 7872546
    Abstract: A dual mode modulator is proposed for driving a power output stage having a serial connection of high-side power FET and low-side power FET. The dual mode modulator includes a PWM modulator operating under a PWM-frequency and a PFM modulator for controlling the power output stage. To improve the dynamic load regulation of the dual mode modulator, a dynamic frequency booster can be added to the dual mode modulator to boost up the PWM-frequency from its normal operating frequency during a PFM-to-PWM mode transition period. Secondly, a dynamic slew rate booster can be added to boost up an error amplifier slew rate of the PWM modulator from its normal operating slew rate during the mode transition period. Thirdly, a dynamic turn-off logic circuit can be added to turn off the low-side power FET during the mode transition period.
    Type: Grant
    Filed: July 7, 2009
    Date of Patent: January 18, 2011
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Behzad Mohtashemi, Allan Chang
  • Patent number: 7868431
    Abstract: A power semiconductor package is disclosed with high inductance rating while exhibiting a reduced foot print. It has a bonded stack of power IC die at bottom, a power inductor at top and a circuit substrate, made of leadframe or printed circuit board, in the middle. The power inductor has a inductor core of closed magnetic loop. The circuit substrate has a first number of bottom half-coil forming conductive elements beneath the inductor core. A second number of top half-coil forming conductive elements, made of bond wires, three dimensionally formed interconnection plates or upper leadframe leads, are located atop the inductor core with both ends of each element connected to respective bottom half-coil forming conductive elements to jointly form an inductive coil enclosing the inductor core. A top encapsulant protectively encases the inductor core, the top half-coil forming conductive elements, the bottom half-coil forming conductive elements and the circuit substrate.
    Type: Grant
    Filed: February 23, 2009
    Date of Patent: January 11, 2011
    Assignee: Alpha and Omega Semiconductor Incorporated
    Inventors: Tao Feng, Xiaotian Zhang, François Hébert, Ming Sun
  • Patent number: 7776658
    Abstract: A semiconductor package is disclosed for packaging two adjacent semiconductor dies atop a circuit substrate. The dies are separated from each other along their longitudinal edges with an inter-die distance. An elevation-adaptive electrical connection connects a top metalized contact of die two to the bottom surface of die one while accommodating for elevation difference between the surfaces. The elevation-adaptive electrical connection includes: a) An L-shaped circuit route that is part of the circuit substrate, extending transversely from a die one longitudinal edge and placing an intermediate contact area next to a die two transverse edge. b) An interconnection plate connecting the top metalized contact area of die two with the intermediate contact area while being formed to accommodate for elevation difference between the contact areas.
    Type: Grant
    Filed: August 7, 2008
    Date of Patent: August 17, 2010
    Assignee: Alpha and Omega Semiconductor, Inc.
    Inventors: Kai Liu, Ming Sun
  • Patent number: 7585705
    Abstract: A method and device structure are disclosed for preventing gate oxide damage of a trench MOSFET during wafer processing while adding an ESD protection module atop the trench MOSFET. The ESD protection module has a low temperature oxide (LTO) bottom layer whose patterning process is found to cause the gate oxide damage. The method includes: a) Fabricate numerous trench MOSFETs on a wafer. b) Add a Si3N4 isolation layer, capable of preventing the LTO patterning process from damaging the gate oxide, atop the wafer. c) Add numerous ESD protection modules atop the Si3N4 isolation layer. d) Remove those portions of the Si3N4 isolation layer that are not beneath the ESD protection modules. In one embodiment, hydrofluoric acid is used as a first etchant for patterning the LTO while hot phosphoric acid is used as a second etchant for removing portions of the Si3N4 isolation layer.
    Type: Grant
    Filed: November 29, 2007
    Date of Patent: September 8, 2009
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Mengyu Pan, Zengyi He, Kaiyu Chen
  • Patent number: 7502148
    Abstract: A multi-lightguide document imaging device is proposed for scanning a document transported atop it. The device includes a line image sensor module having a top sensing area and built-in circuitry for converting an incident line image into video signal output; an intervening rod lens for focusing line image lights from the document onto the sensing area; a number or lightguides lightguide-j (j=1,2, . . . ,N) disposed below the document where each lightguide-j has its own built-in light sources, a transverse cross section spaced at a distance SPCj from the scan line an oriented angularly along a ?-coordinate so as to project a line-illumination aiming at the scan line; and an imager frame having a base for holding the line image sensor module, a multi-element support for holding the rod lens plus the lightguides and a scan line backing portion for backing the document.
    Type: Grant
    Filed: February 16, 2007
    Date of Patent: March 10, 2009
    Assignee: CMOS Sensor, Inc.
    Inventor: Weng-Lyang Wang