Patents Assigned to Alpha & Omega Semiconductor, Inc.
  • Patent number: 8722466
    Abstract: A semiconductor package with connecting plate for internal connection comprise: a plurality of chips each having a plurality of contact areas on a top surface; one or more connecting plates having a plurality of electrically isolated connecting plate portions each connecting a contact area of the semiconductor chips. The method of making the semiconductor package includes the steps of connecting one or more connecting plates to a plurality of semiconductor chips, applying a molding material to encapsulate the chips and the connecting plates, separating a plurality of connecting plate portions of the connecting plates by shallow cutting through or by grinding.
    Type: Grant
    Filed: March 12, 2010
    Date of Patent: May 13, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Jun Lu, Kai Liu, Yan Xun Xue
  • Patent number: 8722467
    Abstract: A die attach method for a semiconductor chip with a back metal layer located at the back surface of the semiconductor chip comprises the steps of forming a bonding ball array including a plurality of bonding balls with a same height on a die attach area at a top surface of a die paddle; depositing a die attach material in the bonding ball array area with a thickness of the die attach material equal or slightly larger than the height of the bonding ball; attaching the semiconductor chip to the die attach area at the top surface of the die paddle by the die attach material, wherein the bonding ball array controls the bond line thickness of the die attach material between the back metal layer and the top surface of the die paddle and prevents the semiconductor chip from rotating on the die attach material when it is melted.
    Type: Grant
    Filed: June 30, 2012
    Date of Patent: May 13, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Lei Shi, Aihua Lu, Yan Xun Xue
  • Patent number: 8722468
    Abstract: A semiconductor encapsulation comprises a lead frame further comprising a chip carrier and a plurality of pins in adjacent to the chip carrier. A plurality of grooves opened from an upper surface of the chip carrier partially dividing the chip carrier into a plurality of chip mounting areas. A bottom portion of the grooves is removed for completely isolate each chip mounting area, wherein a width of the bottom portion of the grooves removed is smaller than a width of the grooves. In one embodiment, a groove is located between the chip carrier and the pins with a bottom portion of the groove removed for isolate the pins from the chip carrier, wherein a width of the bottom of the grooves removed is smaller than a width of the grooves.
    Type: Grant
    Filed: July 25, 2013
    Date of Patent: May 13, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yan Xun Xue, Anup Bhalla, Jun Lu
  • Patent number: 8716985
    Abstract: A power factor correction device comprises a power stage circuit converting input alternating current voltage into input current according to a pulse width modulation signal and outputs the input current to a load generating output voltage on the load, and sampling the input current outputting a correcting current; a current compensating circuit receiving and comparing the correcting current with a reference current signal generating a compensating current signal; a voltage compensating circuit receiving and comparing the output voltage with a reference voltage generating a compensating voltage signal; a multiplication amplifier receiving the compensating current signal and the compensating voltage signal generating an updated reference current signal by multiplying the compensating current signal with the compensating voltage signal; and a pulse width modulation converter receiving the compensating current signal and the compensating voltage signal generating the pulse width modulation signal to synchronize
    Type: Grant
    Filed: February 29, 2012
    Date of Patent: May 6, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Chung-Ping Ku, Wei-Chi Huang
  • Patent number: 8716069
    Abstract: A semiconductor device comprises an aluminum alloy lead-frame with a passivation layer covering an exposed portion of the aluminum alloy lead-frame. Since aluminum alloy is a low-cost material, and its hardness and flexibility are suitable for deformation process, such as punching, bending, molding and the like, aluminum alloy lead frame is suitable for mass production; furthermore, since its weight is much lower than copper or iron-nickel material, aluminum alloy lead frame is very convenient for the production of semiconductor devices.
    Type: Grant
    Filed: September 28, 2012
    Date of Patent: May 6, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yan Xun Xue, Yueh-Se Ho, Yongping Ding
  • Patent number: 8709867
    Abstract: A dual-leadframe multi-chip package comprises a first leadframe with a first die pad, and a second leadframe with a second die pad; a first chip mounted on the first die pad functioning as a high-side MOSFET and second chip mounted on the second die pad functioning as a low-side MOSFET. The package may further comprises a bypass capacity configured as a third chip mounted on the first die pad or integrated with the first chip. The package may further comprise a three-dimensional connecting plate formed as an integrated structure as the second die pad for electrically connecting a top contact area of the first chip to a bottom contact area of the second chip. A top connecting plate connects a top contact area of the second chip and a top contact area of the third chip to an outer pin of the first leadframe.
    Type: Grant
    Filed: March 5, 2012
    Date of Patent: April 29, 2014
    Assignee: Alpha & Omega Semiconductor Inc.
    Inventors: Kai Liu, Lei Shi, Jun Lu, Anup Bhalla
  • Patent number: 8710648
    Abstract: A method to provide a wafer level package with increasing contact pad area comprising the steps of forming a first packaging layer on wafer top surface, grinding the wafer back surface and etch through holes, depositing a metal to fill the through holes and covering wafer backside, cutting through the wafer from wafer backside forming a plurality of grooves separating each chip then depositing a second packaging layer filling the grooves and covering the wafer back metal, reducing the first packaging layer thickness to expose the second packaging layer filling the grooves and forming a plurality of contact pads overlaying the first packaging layer thereafter cutting through the second packaging layer in the grooves to form individual package.
    Type: Grant
    Filed: March 23, 2012
    Date of Patent: April 29, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventor: Yan Xun Xue
  • Patent number: 8709893
    Abstract: The invention relates to a power semiconductor device and its preparation methods thereof. Particularly, the invention aims at providing a method for reducing substrate contribution to the Rdson (drain-source on resistance) of power MOSFETs, and a power MOSFET device made by the method. By forming one or more bottom grooves at the bottom of Si substrate, the on resistance of the power MOSFET device attributed to the substrate is effectively reduced. A matching lead frame base complementary to the substrate with bottom grooves further improves the package of the power MOSFET device.
    Type: Grant
    Filed: August 23, 2011
    Date of Patent: April 29, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yi Su, Daniel Ng, Anup Bhalla, Jun Lu
  • Patent number: 8703545
    Abstract: A semiconductor package is provided with an Aluminum alloy lead-frame without noble metal plated on the Aluminum base lead-frame. Aluminum alloy material with proper alloy composition and ratio for making an aluminum alloy lead-frame is provided. The aluminum alloy lead-frame is electroplated with a first metal electroplating layer, a second electroplating layer and a third electroplating layer in a sequence. The lead-frame electroplated with the first, second and third metal electroplating layers is then used in the fabrication process of a power semiconductor package including chip connecting, wire bonding, and plastic molding. After the molding process, the area of the lead-frame not covered by the molding compound is electroplated with a fourth metal electroplating layer that is not easy to be oxidized when exposing to air.
    Type: Grant
    Filed: February 29, 2012
    Date of Patent: April 22, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Zhiqiang Niu, Ming-Chen Lu, Yan Xun Xue, Yan Huo, Hua Pan, Guo Feng Lian, Jun Lu
  • Patent number: 8692477
    Abstract: A simple, cost-effective and efficient short circuit protection with simple routing of the ground on the PCB is achieved in an asynchronous DC-DC boost converter wherein a voltage sensing controller selectively isolates an input power supply to a load in the event of a short circuit. The controller alleviates need for additional components by utilizing the circuit for under voltage lockout protection and the circuit for overvoltage protection to generate signals for detecting short circuit. A predetermined offset voltage is added to a sensed output voltage to generate a reference voltage that is compared to a sensed input voltage and an output signal having a high state is generated in the event that the reference voltage is less than the sensed input voltage for selectively disabling the source of input power when the output signal is in the high state.
    Type: Grant
    Filed: February 1, 2013
    Date of Patent: April 8, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventor: Gilbert S. Lee
  • Patent number: 8686546
    Abstract: A combined packaged power semiconductor device includes a flipped top source low-side MOSFET electrically connected to a top surface of a die paddle, a first metal interconnection plate connecting between a bottom drain of a high-side MOSFET or a top source of a flipped high-side MOSFET to a bottom drain of the low-side MOSFET, and a second metal interconnection plate stacked on top of the high-side MOSFET chip. The high-side, low-side MOSFET and the IC controller can be packaged three-dimensionally that reduces the overall size of semiconductor devices and can maximize the chip's size within a package of the same size and improves the performance of the semiconductor devices. The top source of flipped low-side MOSFET is connected to the top surface of the die paddle and thus is grounded through the exposed bottom surface of die paddle, which simplifies the shape of exposed bottom surface of the die paddle and maximizes the area to facilitate heat dissipation.
    Type: Grant
    Filed: March 31, 2011
    Date of Patent: April 1, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yueh-Se Ho, Hamza Yilmaz, Yan Xun Xue, Jun Lu
  • Publication number: 20140085760
    Abstract: A protection circuit for a power transistor includes a first transistor connected in parallel with the power transistor and having a control terminal connected to a first power supply voltage through a first resistive element; and a first set of diodes connected between a first terminal and a control terminal of the first transistor. In operation, the voltage at the first terminal of the first transistor is clamped to a clamp voltage and the first transistor is turned on to conduct current in a forward conduction mode when an over-voltage condition occurs at a first terminal of the power transistor.
    Type: Application
    Filed: September 27, 2012
    Publication date: March 27, 2014
    Applicant: ALPHA & OMEGA SEMICONDUCTOR, INC.
    Inventor: Sik K. Lui
  • Patent number: 8669650
    Abstract: A semiconductor device package comprises a lead frame having a die paddle comprising a first chip installation area and a second chip installation area, a recess area formed in the first chip installation area, and multiple metal pillars formed in the recess area, a notch divides the first chip installation area into a transverse base extending transversely and a longitudinal base extending longitudinally, and separates the recess area into a transverse recess part formed in the transverse base and a longitudinal recess part formed in longitudinal base; a portion of a transverse extending part connecting to an external pin extends into a portion inside of the notch.
    Type: Grant
    Filed: September 23, 2011
    Date of Patent: March 11, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Xiaotian Zhang, Hamza Yilmaz, Jun Lu, Xiaoguang Zeng, Ming-Chen Lu
  • Patent number: 8669613
    Abstract: A semiconductor die with integrated MOSFET and diode-connected enhancement mode JFET is disclosed. The MOSFET-JFET die includes common semiconductor substrate region (CSSR) of type-1 conductivity. A MOSFET device and a diode-connected enhancement mode JFET (DCE-JFET) device are located upon CSSR. The DCE-JFET device has the CSSR as its DCE-JFET drain. At least two DCE-JFET gate regions of type-2 conductivity located upon the DCE-JFET drain and laterally separated from each other with a DCE-JFET gate spacing. At least a DCE-JFET source of type-1 conductivity located upon the CSSR and between the DCE-JFET gates. A top DCE-JFET electrode, located atop and in contact with the DCE-JFET gate regions and DCE-JFET source regions. When properly configured, the DCE-JFET simultaneously exhibits a forward voltage Vf substantially lower than that of a PN junction diode while the reverse leakage current can be made comparable to that of a PN junction diode.
    Type: Grant
    Filed: September 29, 2010
    Date of Patent: March 11, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Sik Lui, Wei Wang
  • Publication number: 20140049293
    Abstract: A three-dimensional (3D) gate driver integrated circuit includes a high-side integrated circuit stacked on a low-side integrated circuit where the high-side integrated circuit and the low-side integrated circuit are interconnected using through-silicon vias (TSV). As thus formed, the high-side integrated circuit and the low-side integrated circuit can be formed without termination regions and without buried layers.
    Type: Application
    Filed: August 17, 2012
    Publication date: February 20, 2014
    Applicant: ALPHA & OMEGA SEMICONDUCTOR, INC.
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 8642397
    Abstract: A wafer-level semiconductor package method comprising the step of providing a first wafer comprising a plurality of first dies each having a first, a second and a third electrodes formed on its front surface; attaching a second die having a fourth and a fifth electrodes formed on its front surface and a sixth electrode formed at its back surface onto each of the first die of the first wafer with the sixth electrode at the back surface of the second die attached and electrically connected to the second electrode at the front surface of the first die; and cutting the first wafer to singulate individual semiconductor packages.
    Type: Grant
    Filed: September 9, 2012
    Date of Patent: February 4, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yuping Gong, Yan Xun Xue, Ping Huang
  • Patent number: 8642429
    Abstract: A semiconductor device structure with an oxide-filled large deep trench (OFLDT) portion having trench size TCS and trench depth TCD is disclosed. 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: June 29, 2012
    Date of Patent: February 4, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Xiaobin Wang, Anup Bhalla, Yeeherg Lee
  • Patent number: 8642385
    Abstract: The present invention proposes a package for semiconductor device and the fabrication method for integrally encapsulating a whole semiconductor chip within a molding compound. In the semicondcutor device package, bonding pads distributed on the top of the chip are redistributed into an array of redistributed bonding pads located in an dielectric layer by utilizing the redistribution technique. The electrodes or signal terminals on the top of the semiconductor chip are connected to an electrode metal segment on the bottom of the chip by conductive materials filled in through holes formed in a silicon substrate of a semiconductor wafer. Furthermore, the top molding portion and the bottom molding portion seal the semiconductor chip completely, thus providing optimum mechanical and electrical protections.
    Type: Grant
    Filed: August 9, 2011
    Date of Patent: February 4, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Yan Xun Xue, Ping Huang, Yueh-Se Ho, Hamza Yilmaz, Jun Lu, Ming-Chen Lu
  • Patent number: 8643137
    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: June 4, 2012
    Date of Patent: February 4, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventors: Shekar Mallikarjunaswamy, Amit Paul
  • Patent number: 8633512
    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+½Vzx. In another embodiment, a proposed power switching device with integrated VDS-clamping includes a switching FET; and 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: April 24, 2012
    Date of Patent: January 21, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventor: Sanjay Havanur