Patents Assigned to Alpha and Omega Semiconductor (Cayman) LTD
  • Publication number: 20190006285
    Abstract: A method comprises the steps of providing a semiconductor device wafer; forming a first plurality of alignment marks on a first side of the semiconductor device wafer; forming a first pattern of a first conductivity type; forming a second plurality of alignment marks on a second side of the semiconductor device wafer; forming a bonded wafer by bonding a carrier wafer to the semiconductor device wafer; forming a third plurality of alignment marks on a free side of the carrier wafer; applying a grinding process; forming a plurality of device structure members; removing the carrier wafer; applying an implanting process and an annealing process; applying a metallization process and applying a singulation process.
    Type: Application
    Filed: June 14, 2018
    Publication date: January 3, 2019
    Applicant: Alpha and Omega Semiconductor (Cayman) Ltd.
    Inventors: Lei Zhang, Hongyong Xue, Jian Wang, Runtao Ning
  • Patent number: 10170559
    Abstract: An RC-IGBT includes a semiconductor body formed having a base region incorporating a field stop zone where the base region and the field stop zone are both formed using an epitaxial process and the field stop zone has an enhanced doping profile to realize improved soft-switching performance for the semiconductor device. In alternate embodiments, RC-IGBT device, including the epitaxial layer field stop zone, are realized through a fabrication process that uses front side processing only to form the backside contact regions and the front side device region. The fabrication method forms an RC-IGBT device using front side processing to form the backside contact regions and then using wafer bonding process to flip the semiconductor structure onto a carrier wafer so that front side processing is used again to form the device region.
    Type: Grant
    Filed: June 29, 2017
    Date of Patent: January 1, 2019
    Assignee: Alpha and Omega Semiconductor (Cayman) Ltd.
    Inventors: Hongyong Xue, Lei Zhang, Brian Schorr, Chris Wiebe, Wenjun Li
  • Patent number: 10157702
    Abstract: A voltage converter comprises a second controller as a power switch of the secondary side of the transformer for comparing a detection voltage representing an output voltage and/or load current with a first reference voltage and generating a control signal, and a coupling element for transmitting the control signal generated by the second controller to the first controller on the primary side of the transformer enabling the first controller to generate a first pulse signal driving the power switch to control the on/off state of the primary side winding.
    Type: Grant
    Filed: August 18, 2016
    Date of Patent: December 18, 2018
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.
    Inventors: Tien-Chi Lin, Yu-Ming Chen, Jung-Pei Cheng, Pei-Lun Huang
  • Patent number: 10157904
    Abstract: A transient voltage suppressor (TVS) is constructed as an NPN bipolar transistor including individually optimized collector-base and emitter-base junctions both with avalanche mode breakdown. The TVS device is constructed using a base that includes a lightly doped base region bordered by a pair of more heavily doped base regions. The two more heavily doped base regions are used to form the collector-base junction and the emitter-base junction both as avalanche breakdown junctions. The lightly doped base region between the collector-base and emitter-base doping regions ensures low leakage current in the TVS device. In this manner, the TVS bipolar transistor of the present invention provides high surge protection with robust clamping while ensuring low leakage current.
    Type: Grant
    Filed: March 31, 2017
    Date of Patent: December 18, 2018
    Assignee: Alpha and Omega Semiconductor (Cayman) Ltd.
    Inventors: Shekar Mallikarjunaswamy, Ning Shi
  • Patent number: 10141300
    Abstract: A transient voltage suppressor (TVS) circuit includes a P-N junction diode and a silicon controlled rectifier (SCR) formed integrated in a lateral device structure of a semiconductor layer. The lateral device structure includes multiple fingers of semiconductor regions arranged laterally along a first direction on a major surface of the semiconductor layer, defining current conducting regions between the fingers. The current paths for the SCR and the P-N junction diode are formed in each current conducting region but the current path for the SCR is predominantly separated from the current path for the P-N junction diode in each current conducting region in a second direction orthogonal to the first direction on the major surface of the semiconductor layer. The TVS device of the present invention realizes low capacitance at the protected node. The TVS device is suitable for protecting data pins of an integrated circuit, especially when the data pins are used in high speed applications.
    Type: Grant
    Filed: October 19, 2017
    Date of Patent: November 27, 2018
    Assignee: Alpha and Omega Semiconductor (Cayman) Ltd.
    Inventor: Shekar Mallikarjunaswamy
  • Patent number: 10141249
    Abstract: An intelligent power module (IPM) has a first, second, third and fourth die paddles, a first, second, third, fourth, fifth and sixth metal-oxide-semiconductor field-effect transistors (MOSFETs), a tie bar, a metal slug, a plurality of spacers, a plurality of leads and a molding encapsulation. The molding encapsulation encloses the first, second, third and fourth die paddles, the first, second, third, fourth, fifth and sixth MOSFETs, the tie bar and the plurality of spacers. A bottom surface of the metal slug is exposed from the molding encapsulation. A process for fabricating the IPM comprises preparing the first, second, third and fourth die paddles, the first, second, third, fourth, fifth and sixth MOSFETs, the tie bar, the plurality of leads, the metal slug and the plurality of spacers and applying a molding process to form the molding encapsulation.
    Type: Grant
    Filed: September 8, 2017
    Date of Patent: November 27, 2018
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.
    Inventors: Zhiqiang Niu, Bum-Seok Suh, Wonjin Cho, Jun Lu
  • Patent number: 10141264
    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 21, 2018
    Date of Patent: November 27, 2018
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.
    Inventor: Yan Xun Xue
  • Patent number: 10063146
    Abstract: Aspects of the present disclosure describe a SMPS system, comprising a SMPS and an inductor current sensing device. The SMPS comprise a high-side (HS) switch and a low-side (LS) switch coupled in series and an output filter including an inductor and a capacitor coupled to a switch node formed by the HS and LS switches. An inductor current is supplied by the inductor to a load. The inductor current sensing device coupled across the LS switch has a first input configured to receive a node signal indicating a voltage level at the switch node, a second input configured to receive an input voltage of the system and a third input configured to receive an output voltage of the system.
    Type: Grant
    Filed: March 31, 2017
    Date of Patent: August 28, 2018
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.
    Inventor: Gilbert S. Z. Lee
  • Patent number: 10062682
    Abstract: A bidirectional transient voltage suppressor (TVS) circuit for data pins of electronic devices includes two sets of steering diodes and a diode triggered clamp device in some embodiment. In other embodiments, a bidirectional transient voltage suppressor (TVS) circuit for data pins of electronic devices includes two sets of steering diodes with a clamp device merged with a steering diode in each set. The TVS circuit is constructed to realize low capacitance at the protected nodes and improved clamping voltage for robust protection against surge evens. In some embodiments, the TVS circuit realizes low capacitance at the protected nodes by fully or almost completely depleting the P-N junction connected to the protected nodes in the operating voltage range. In this manner, the TVS circuit does not present undesirable parasitic capacitance to the data pins being protected, especially when the data pins are applied in high speed applications.
    Type: Grant
    Filed: May 25, 2017
    Date of Patent: August 28, 2018
    Assignee: Alpha and Omega Semiconductor (Cayman) Ltd.
    Inventors: Shekar Mallikarjunaswamy, Ning Shi
  • Patent number: 10056822
    Abstract: A control circuit for a switching regulator implementing a fixed frequency constant on-time control scheme incorporates a reference voltage generator to generate a reference voltage ramp that varies over substantially the entire switching period. In one embodiment, the reference voltage increases from an initial voltage value at the start of each switching period towards the end of the switching period and is reset to the initial voltage value at the end of each switching period. The reference voltage ramp ensures stable feedback control operation in the switching regulator without introducing voltage offset for all output voltage values. The control circuit enables the switching regulator to apply constant on-time control scheme while using an output capacitor having any ESR value, including an output capacitor with low or zero ESR.
    Type: Grant
    Filed: December 26, 2017
    Date of Patent: August 21, 2018
    Assignee: Alpha and Omega Semiconductor (Cayman) Ltd.
    Inventors: Zhiye Zhang, Zhinan Wei
  • Patent number: 10056893
    Abstract: A power module has a lead frame, a first power chip, a second power chip, a plurality of single in-line leads, a gate drive and protection integrated circuit (IC), a plurality of bonding wires and a molding encapsulation. The first and second power chips are attached to a top surface of the lead frame. The plurality of single in-line leads has a high voltage power lead, a low voltage power lead and a plurality of signal control leads. The low voltage power lead has a lead portion and an extension portion. The gate drive and protection IC is attached to the extension portion of the low voltage power lead. The molding encapsulation encloses the first and second power chips, the extension portion of the low voltage power lead, the gate drive and protection IC, the plurality of bonding wires and at least a majority portion of the lead frame.
    Type: Grant
    Filed: October 16, 2016
    Date of Patent: August 21, 2018
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.
    Inventors: Bum-Seok Suh, Zhiqiang Niu, Wonjin Cho, Son Tran, James Rachana Bou
  • Patent number: 9997593
    Abstract: A trench type power semiconductor device with improved breakdown voltage and UIS performance and a method for preparation the device are disclosed. The trench type power semiconductor device includes a first contact hole formed in a mesa in the active area and a second contact hole formed in a mesa in an active to termination intermediate area, where the first contact hole is deeper and wider than the second contact hole. The method comprises the steps of providing a semiconductor substrate, etching an epitaxial layer, depositing a conductive material, depositing an insulation passivation layer and etching through the insulation passivation layer.
    Type: Grant
    Filed: July 10, 2017
    Date of Patent: June 12, 2018
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.
    Inventors: Yongping Ding, Hamza Yilmaz, Xiaobin Wang, Madhur Bobde
  • Patent number: 9966328
    Abstract: A semiconductor power device is disclosed. The semiconductor power device comprises a lead frame unit, two or more pluralities of single in-line leads, two or more semiconductor chip stacks, and a molding encapsulation. Each semiconductor chip stack includes a high-side semiconductor chip, a low-side semiconductor chip and a clip connecting a top surface of the high-side semiconductor chip to a bottom surface of the low-side semiconductor chip. This invention further discloses a method for fabricating semiconductor power devices.
    Type: Grant
    Filed: July 25, 2017
    Date of Patent: May 8, 2018
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.
    Inventors: Yan Xun Xue, Zhiqiang Niu
  • Patent number: 9954449
    Abstract: An output current calculating circuit for a flyback converter operating under CCM and DCM is disclosed. The off current value IOFF and the blanking current value ILEB flowing through a sensing resistor are calculated using a detection module and are summed together using a current summing unit. A voltage converted from the sum value of the off current value IOFF and the blanking current value ILEB is transmitted through an output stage in a predetermined time ratio of a cycle with the duty cycle determined by a logic control unit, in which the logic control unit controls the output stage to receive the voltage converted from sum current in a predetermined time period of each cycle, and prevents the output stage to receive the voltage converted from sum current in the remaining time other than such predetermined time period of each cycle.
    Type: Grant
    Filed: November 3, 2016
    Date of Patent: April 24, 2018
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.
    Inventors: Yu-Ming Chen, Jung-Pei Cheng, Pei-Lun Huang
  • Patent number: 9954455
    Abstract: The present invention discloses a constant on-time isolated converter comprising a transformer with a primary side and a secondary side. The primary side is connected to an electronic switch and secondary-side is connected to a load and a processor. The processor is connected to a driver on primary side through at least one coupling element and to the electronic switch. The processor receives an output voltage or an output current across the load generating a control signal accordingly. The driver receives the control signal through the coupling element and accordingly changes the ON/OFF state of the electronic switch, regulating the output voltage and the output current via the transformer, where the duration of the ON/OFF state of the electronic switch is determined between the moment control signal changes from negative to positive and the moment it changes from positive to negative to achieve a high-speed load transient response.
    Type: Grant
    Filed: December 7, 2014
    Date of Patent: April 24, 2018
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.
    Inventors: Tien-Chi Lin, Chih-Yuan Liu, Yueh-Ping Yu, Jung-Pei Cheng, Pei-Lun Huang
  • Publication number: 20180109249
    Abstract: A power module has a lead frame, a first power chip, a second power chip, a plurality of single in-line leads, a gate drive and protection integrated circuit (IC), a plurality of bonding wires and a molding encapsulation. The first and second power chips are attached to a top surface of the lead frame. The plurality of single in-line leads has a high voltage power lead, a low voltage power lead and a plurality of signal control leads. The low voltage power lead has a lead portion and an extension portion. The gate drive and protection IC is attached to the extension portion of the low voltage power lead. The molding encapsulation encloses the first and second power chips, the extension portion of the low voltage power lead, the gate drive and protection IC, the plurality of bonding wires and at least a majority portion of the lead frame.
    Type: Application
    Filed: October 16, 2016
    Publication date: April 19, 2018
    Applicant: Alpha and Omega Semiconductor (Cayman) Ltd.
    Inventors: Bum-Seok Suh, Zhiqiang Niu, Wonjin Cho, Son Tran, James Rachana Bou
  • Publication number: 20180108601
    Abstract: An intelligent power module (IPM) has a first, second, third and fourth die paddles, a first, second, third, fourth, fifth and sixth metal-oxide-semiconductor field-effect transistors (MOSFETs), a tie bar, a metal slug, a plurality of spacers, a plurality of leads and a molding encapsulation. The molding encapsulation encloses the first, second, third and fourth die paddles, the first, second, third, fourth, fifth and sixth MOSFETs, the tie bar and the plurality of spacers. A bottom surface of the metal slug is exposed from the molding encapsulation. A process for fabricating the IPM comprises preparing the first, second, third and fourth die paddles, the first, second, third, fourth, fifth and sixth MOSFETs, the tie bar, the plurality of leads, the metal slug and the plurality of spacers and applying a molding process to form the molding encapsulation.
    Type: Application
    Filed: September 8, 2017
    Publication date: April 19, 2018
    Applicant: Alpha and Omega Semiconductor (Cayman) Ltd.
    Inventors: Zhiqiang Niu, Bum-Seok Suh, Wonjin Cho, Jun Lu
  • Publication number: 20180108598
    Abstract: An intelligent power module (IPM) has a first, second, third and fourth die paddles, a first, second, third, fourth, fifth and sixth metal-oxide-semiconductor field-effect transistors (MOSFETs), a tie bar, an IC, a plurality of leads and a molding encapsulation. The first MOSFET is attached to the first die paddle. The second MOSFET is attached to the second die paddle. The third MOSFET is attached to the third die paddle. The fourth, fifth and sixth MOSFETs are attached to the fourth die paddle. The IC is attached to the tie bar. The molding encapsulation encloses the first, second, third and fourth die paddles, the first, second, third, fourth, fifth and sixth MOSFETs, the tie bar and the IC. The IPM is a small-outline package. It reduces system design time and improves reliability. The IC includes boost diodes. It reduces a package size of the IPM.
    Type: Application
    Filed: May 22, 2017
    Publication date: April 19, 2018
    Applicant: Alpha and Omega Semiconductor (Cayman) Ltd.
    Inventors: Zhiqiang Niu, Bum-Seok Suh, Jun Lu, Wonjin Cho
  • Patent number: 9881856
    Abstract: An intelligent power module (IPM) has a first, second, third and fourth die paddles, a first, second, third, fourth, fifth and sixth transistors, a tie bar, a low voltage IC, a high voltage IC, a first, second and third boost diodes, a plurality of leads and a molding encapsulation. The first transistor is attached to the first die paddle. The second transistor is attached to the second die paddle. The third transistor is attached to the third die paddle. The fourth, fifth and sixth transistor s are attached to the fourth die paddle. The low and high voltage ICs are attached to the tie bar. The molding encapsulation encloses the first, second, third and fourth die paddles, the first, second, third, fourth, fifth and sixth transistors, the tie bar, the low and high voltage ICs, and the first, second and third boost diodes. The IPM has a reduced top surface area and a reduced number of leads compared to a conventional IPM.
    Type: Grant
    Filed: May 19, 2017
    Date of Patent: January 30, 2018
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.
    Inventors: Bum-Seok Suh, Zhiqiang Niu, Wonjin Cho, Cheow Khoon Oh, Son Tran, James Rachana Bou
  • Patent number: 9882500
    Abstract: The present invention relates to a power supply device for voltage converter, which includes a master switch, a first controller for generating a first pulse signal to drive the master switch to be turned on and turned off, a second controller for comparing a detection voltage representing an output voltage and/or load current with a first reference voltage to determine the logic state of a control signal generated by the second controller, and a coupling element connected between the first controller and the second controller for transmitting the logic state of the control signal to the first controller and enabling the first controller to determine the logic state of the first pulse signal according to the logic state of the control signal. The second controller includes a driving module for generating a second control signal to drive a synchronous switch to be turned on and turned off.
    Type: Grant
    Filed: August 18, 2016
    Date of Patent: January 30, 2018
    Assignee: Alpha & Omega Semiconductor (Cayman), Ltd.
    Inventors: Tien-Chi Lin, Yu-Ming Chen, Jung-Pei Cheng, Yung-Chuan Hsu, Yueh-Ping Yu, Wei-Ting Wang, Pei-Lun Huang