Patents Assigned to Alpha & Omega Semiconductor (Cayman), Ltd.
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Patent number: 10714580Abstract: A trench metal-oxide-semiconductor field-effect transistor (MOSFET) device, comprising a substrate of a first conductivity type, a body region of a second conductivity type, a gate electrode formed in a gate trench extending in the body region and substrate, a lightly doped source region and a heavily doped source region formed in the body region, and a trench contact extending to the body region formed in a contact trench. A contact implant of the second conductivity type is formed surrounding a bottom portion of the contact trench and it also forms surrounding sidewall portions of the contact trench where it contacts with the lightly doped source region to form a PN diode.Type: GrantFiled: February 7, 2018Date of Patent: July 14, 2020Assignee: Alpha and Omega Semiconductor (Cayman) Ltd.Inventor: Sik Lui
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Patent number: 10692851Abstract: 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: GrantFiled: November 1, 2018Date of Patent: June 23, 2020Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.Inventors: Shekar Mallikarjunaswamy, Ning Shi
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Publication number: 20200194395Abstract: A semiconductor package has a plurality of pillars or portions of a plurality of lead strips, a plurality of semiconductor devices, one or two molding encapsulations and a plurality of electrical interconnections. The semiconductor package excludes a wire. The semiconductor package excludes a clip. A method is applied to fabricate semiconductor packages. The method includes providing a removable carrier; forming a plurality of pillars or a plurality of lead strips; attaching a plurality of semiconductor devices; forming one or two molding encapsulations; forming a plurality of electrical interconnections and removing the removable carrier. The method may further include a singulation process.Type: ApplicationFiled: December 18, 2018Publication date: June 18, 2020Applicant: Alpha and Omega Semiconductor (Cayman) Ltd.Inventors: Xiaotian Zhang, Yan Xun Xue, Long-Ching Wang, Yueh-Se Ho, Zhiqiang Niu
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Publication number: 20200194347Abstract: A semiconductor package has a plurality of pillars or portions of a plurality of lead strips, a plurality of semiconductor devices, one or two molding encapsulations and a plurality of electrical interconnections. The semiconductor package excludes a wire. The semiconductor package excludes a clip. A method is applied to fabricate semiconductor packages. The method includes providing a removable carrier; forming a plurality of pillars or a plurality of lead strips; attaching a plurality of semiconductor devices; forming one or two molding encapsulations; forming a plurality of electrical interconnections and removing the removable carrier. The method may further include a singulation process.Type: ApplicationFiled: December 18, 2018Publication date: June 18, 2020Applicant: Alpha and Omega Semiconductor (Cayman) Ltd.Inventors: Yan Xun Xue, Xiaotian Zhang, Long-Ching Wang, Yueh-Se Ho, Zhiqiang Niu
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Patent number: 10686038Abstract: An RC-IGBT includes a semiconductor body 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: GrantFiled: November 2, 2018Date of Patent: June 16, 2020Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.Inventors: Hongyong Xue, Lei Zhang, Brian Schorr, Chris Wiebe, Wenjun Li
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Patent number: 10665551Abstract: A trench-type metal-oxide-semiconductor field-effect transistor (MOSFET) device and a fabrication method are disclosed. A semiconductor substrate of a first conductivity type is provided. A plurality of first trenches arranged side by side in a first stripe layout extending along a first direction in a first preset area of the semiconductor substrate are formed. A plurality of second trenches arranged side by side in a second stripe layout extending along a second direction perpendicular to the first direction in a second preset area of the semiconductor substrate are formed. The plurality of first trenches and the plurality of second trenches are filled with a conductive material so as to form a plurality of control gates.Type: GrantFiled: June 21, 2018Date of Patent: May 26, 2020Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.Inventors: Xiaobin Wang, Madhur Bobde, Paul Thorup
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Patent number: 10651750Abstract: A constant on-time isolated converter comprises 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: GrantFiled: March 11, 2019Date of Patent: May 12, 2020Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.Inventors: Tien-Chi Lin, Chih-Yuan Liu, Yung-Chuan Hsu, Pei-Lun Huang
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Patent number: 10644102Abstract: A trench metal-oxide-semiconductor field-effect transistor (MOSFET) device includes a combination of shielded trench gate structure and a superjunction structure within an epitaxial layer including alternating n-doped and p-doped columns in an a drift region. In one example the gate trenches are formed in and over n-doped columns that have an extra charge region near and adjacent to the lower portion of the corresponding gate trench. The extra charge is balanced due to the shield electrodes in the gate trenches.Type: GrantFiled: December 28, 2017Date of Patent: May 5, 2020Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.Inventors: Karthik Padmanabhan, Lingpeng Guan, Madhur Bobde, Jian Wang, Lei Zhang
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Patent number: 10630080Abstract: A charger comprises a housing, a first multi-layer printed circuit board (PCB), a second multi-layer PCB, and a third multi-layer PCB. The first PCB comprises at least a portion of a primary side circuit. The second PCB comprises at least a portion of a secondary side circuit. The third PCB is perpendicular to the first PCB and the second PCB. An isolation coupling element is disposed on the third PCB. The isolation coupling element comprises a multi-layer PCB. The first PCB comprises a high voltage (HV) semiconductor package. A surface of a die paddle of the HV semiconductor package is exposed from a molding encapsulation of the HV semiconductor package.Type: GrantFiled: June 28, 2019Date of Patent: April 21, 2020Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.Inventors: Pei-Lun Huang, Yu-Ming Chen, Tien-Chi Lin, Jung-Pei Cheng, Yueh-Ping Yu, Zhi-Qiang Niu, Xiaotian Zhang, Long-Ching Wang
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Patent number: 10600727Abstract: An intelligent power module (IPM) has a first, second, third and fourth die supporting elements, a first, second, third, fourth, fifth and sixth transistors, a connection member, a low voltage IC, a high voltage IC, a plurality of leads and a molding encapsulation. The first transistor is attached to the first die supporting element. The second transistor is attached to the second die supporting element. The third transistor is attached to the third die supporting element. The fourth, fifth and sixth transistor s are attached to the fourth die supporting element. The low and high voltage ICs are attached to the connection member. The molding encapsulation encloses the first, second, third and fourth die supporting elements, the first, second, third, fourth, fifth and sixth transistors, the connection member and the low and high voltage ICs. The IPM has a reduced thermal resistance of junction-to-case (RthJC) compared to a conventional IPM.Type: GrantFiled: September 5, 2018Date of Patent: March 24, 2020Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.Inventors: Zhiqiang Niu, Bum-Seok Suh, Jun Lu, Son Tran, Wanki Hong, Guobing Shen, Xiaoguang Zeng, Mary Jane R. Alin
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Patent number: 10580868Abstract: A superjunction power semiconductor device includes a termination region with superjunction structures having higher breakdown voltage than the breakdown voltage of the active cell region. In one embodiment, the termination region includes superjunction structures having lower column charge as compared to the superjunction structures formed in the active cell region. In other embodiments, a superjunction power semiconductor device incorporating superjunction structures with slanted sidewalls where the grading of the superjunction columns in the termination region is reduced as compared to the column grading in the active cell region. The power semiconductor device is made more robust by ensuring any breakdown occurs in the core region as opposed to the termination region. Furthermore, the manufacturing process window for the power semiconductor device is enhanced to improve the manufacturing yield of the power semiconductor device.Type: GrantFiled: March 27, 2018Date of Patent: March 3, 2020Assignee: Alpha and Omega Semiconductor (Cayman) Ltd.Inventors: Madhur Bobde, Karthik Padmanabhan, Lingpeng Guan
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Publication number: 20190385863Abstract: A semiconductor device comprising a substrate layer, an epitaxial layer, a dielectric layer, a first aluminum layer, a first titanium interlayer and a second aluminum layer. The first titanium interlayer is disposed between the first aluminum layer and the second aluminum layer. A process for fabricating a semiconductor device comprising the steps of: preparing a semiconductor wafer; depositing a first aluminum layer onto the semiconductor wafer; depositing a first titanium interlayer onto the first aluminum layer; depositing a second aluminum layer onto the first titanium interlayer; applying an etching process so that a plurality of trenches are formed so as to expose a plurality of top surfaces of a dielectric layer; and applying a singulation process so as to form a plurality of separated semiconductor devices.Type: ApplicationFiled: August 29, 2019Publication date: December 19, 2019Applicant: Alpha and Omega Semiconductor (Cayman) Ltd.Inventors: Wei He, Chris Wiebe, Hongyong Xue
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Publication number: 20190385953Abstract: A high voltage (HV) converter implemented on a printed circuit board (PCB) includes a double diffused metal oxide semiconductor (DMOS) package comprising a lead frame and a main DMOS chip. The lead frame includes a gate section electrically connected to a gate electrode of the main DMOS chip, a source section electrically connected to a source electrode of the main DMOS chip and a drain section electrically connected to a drain electrode of the main DMOS chip. The PCB layout includes a large area source copper pad attached to and overlapping the source section of the DMOS package to facilitate cooling and a small area drain copper pad attached to and overlapping the drain section of the DMOS package to reduce electromagnetic interference (EMI) noise.Type: ApplicationFiled: August 29, 2019Publication date: December 19, 2019Applicant: Alpha and Omega Semiconductor (Cayman) Ltd.Inventors: Zhiqiang Niu, Kuang Ming Chang, Lin Chen, Ning Sun, QiHong Huang, Tzu-Hsin Lu
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Patent number: 10504823Abstract: A power semiconductor package has a small footprint. A preparation method is used to fabricate the power semiconductor package. A first semiconductor chip and a second semiconductor chip are attached to a front side and a back side of a die paddle respectively. Conductive pads are then attached to electrodes at top surfaces of the first and second semiconductor chips. It is followed by a formation of a plastic package body covering the die paddle, the first and second semiconductor chips, and the conductive pads. Side surfaces of the conductive pads are exposed from a side surface of the plastic package body.Type: GrantFiled: March 14, 2017Date of Patent: December 10, 2019Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.Inventors: Hongtao Gao, Jun Lu, Ming-Chen Lu, Jianxin Ye, Yan Huo, Hua Pan
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Publication number: 20190372463Abstract: The invention proposes a system and method for extending the maximum duty cycle of a step-down switching converter to nearly 100% while maintaining a constant switching frequency. The system includes a voltage mode or current mode step-down converter driven by a leading edge blanking (LEB) signal, which operates at the desired switching frequency. More particularly, the LEB signal is connected to a slope generator and/or a current sensing network. In each switching cycle, the LEB signal forces the slope signal and/or current sensing signal to reinitiate, thereby achieving a constant switching frequency and disassociating the switching frequency of the converter from the error voltage VCOMP. Corresponding methods for how to extend the maximum duty cycle of a step-down switching converter while maintaining a constant frequency are also disclosed.Type: ApplicationFiled: August 15, 2019Publication date: December 5, 2019Applicant: Alpha and Omega Semiconductor (Cayman) Ltd.Inventor: Youngbok Kim
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Patent number: 10497697Abstract: A transient voltage suppressor (TVS) circuit includes a first finger and a second finger of semiconductor regions arranged laterally along a first direction on a major surface of a semiconductor layer, the first finger and second finger extending in a second direction orthogonal to the first direction on the major surface of the semiconductor layer. The semiconductor regions in a first portion of the first and second fingers form a silicon controlled rectifier and the semiconductor regions in a second portion of the first and second fingers form a P-N junction diode.Type: GrantFiled: October 16, 2018Date of Patent: December 3, 2019Assignee: Alpha and Omega Semiconductor (Cayman) Ltd.Inventor: Shekar Mallikarjunaswamy
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Patent number: 10477626Abstract: A controller for driving a power switch incorporates a hard turn-on disable circuit to prevent the power switch from turning on when the power switch is sustaining a high voltage value. The hard turn-on disable circuit includes a hard turn-on detection circuit and a protection logic circuit. The hard turn-on disable circuit is configured to block or to pass the system input signal to the normal gate drive circuit of the power switch depending on the detection indicator signal. In particular, the protection logic circuit blocks the system input signal VIN in response to a high voltage detection so that the power switch ignores the system input signal VIN, which may be erroneous, and the power switch is prevented from undesirable hard switching.Type: GrantFiled: March 20, 2017Date of Patent: November 12, 2019Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.Inventors: Son Tran, Bum-Seok Suh, Wonjin Cho
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Patent number: 10476494Abstract: An intelligent power module includes a power switch, a freewheeling device, and a controller circuit incorporating a gate drive circuit and one or more power switch protection circuits. In one embodiment, the power switch is an insulated gate bipolar transistor (IGBT) device, the freewheeling device is a PN junction diode, and the controller circuit is implemented as a semiconductor integrated circuit (IC). The power module implements protection functions for the power switching device where the protection circuits are formed on the controller circuit IC and co-packaged with the power switch. In some embodiments, the control circuit in the power module includes an active soft-start circuit which is activated to realize soft-start of the power switch. In other embodiments, the control circuit in the power module includes an active turn-on pulse control circuit to detect for abnormal system input signal pulse events and block system undesired input pulses.Type: GrantFiled: March 20, 2017Date of Patent: November 12, 2019Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.Inventors: Bum-Seok Suh, Wonjin Cho, Son Tran
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Publication number: 20190318979Abstract: A charger includes a thermal conductive plate for heat dissipation, and a transistor. The transistor includes a drain terminal of a first pulsating voltage level, and a source terminal of a second pulsating voltage level. The second pulsating voltage level is lower than the first pulsating voltage level. The source terminal is disposed closer to the thermal conductive plate than the drain terminal.Type: ApplicationFiled: April 14, 2018Publication date: October 17, 2019Applicant: Alpha and Omega Semiconductor (Cayman) Ltd.Inventors: Yu-Ming Chen, Tien-Chi Lin, GUAN-YU Lin, TIN-WEI Chen
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Patent number: 10438900Abstract: A high voltage (HV) converter implemented on a printed circuit board (PCB) includes a double diffused metal oxide semiconductor (DMOS) package comprising a lead frame and a main DMOS chip. The lead frame includes a gate section electrically connected to a gate electrode of the main DMOS chip, a source section electrically connected to a source electrode of the main DMOS chip and a drain section electrically connected to a drain electrode of the main DMOS chip. The PCB layout includes a large area source copper pad attached to and overlapping the source section of the DMOS package to facilitate cooling and a small area drain copper pad attached to and overlapping the drain section of the DMOS package to reduce electromagnetic interference (EMI) noise.Type: GrantFiled: March 29, 2018Date of Patent: October 8, 2019Assignee: Alpha and Omega Semiconductor (Cayman) Ltd.Inventors: Zhiqiang Niu, Kuang Ming Chang, Lin Chen, Ning Sun, QiHong Huang