Patents by Inventor Zhanming LI

Zhanming LI 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).

  • Publication number: 20240021677
    Abstract: Packaging structures for lateral high voltage gallium nitride (GaN) devices achieve electrical isolation while also maintaining thermal dissipation is provided. The electrical isolation reduces or eliminates vertical leakage current, improving high voltage performance with the semi-insulating layer for adhering the lateral semiconductor power device chip to the back-plate. The packages may use or be compatible standards such as JEDEC, which reduces packaging cost and facilitates implementation of the packaged devices in conventional circuit design approaches.
    Type: Application
    Filed: August 2, 2023
    Publication date: January 18, 2024
    Inventors: Zhanming LI, Zeyu WAN
  • Publication number: 20220109048
    Abstract: A gallium nitride (GaN) semiconductor device has first and second electrodes connected to a top metal layer disposed in complementary first and second irregular shapes, each irregular shape including a wide connection area at a first end, a tapered area, and a narrow area at a second end. The first and second irregular shapes are arranged adjacent each other along complementary edges such that a gap between the complementary edges is of substantially constant width. The first and second wide connection areas include pads for wire bond or land grid array electrical connections to external circuitry. The first and second irregular shapes for source and drain metal of a field effect transistor (FET) or high electron mobility transistor (HEMT) allows the width of the gate finger to be short so that electrical current injected from the gate can reach all portions of the gate fingers efficiently during high frequency switching, making the topology suitable for high voltage power devices.
    Type: Application
    Filed: September 28, 2021
    Publication date: April 7, 2022
    Inventors: Zhanming Li, Yan-Fei Liu, Wai Tung Ng
  • Patent number: 11107755
    Abstract: Packaging methods and structures for lateral high voltage gallium nitride (GaN) devices achieve electrical isolation while also maintaining thermal dissipation. The electrical isolation reduces or eliminates vertical leakage current, improving high voltage performance. The packages may use or be compatible standards such as JEDEC, which reduces packaging cost and facilitates implementation of the packaged devices in conventional circuit design approaches.
    Type: Grant
    Filed: May 10, 2020
    Date of Patent: August 31, 2021
    Inventors: Zhanming Li, Yue Fu, Yan-Fei Liu
  • Patent number: 10939553
    Abstract: A packaged GaN semiconductor device with improved heat dissipation is provided. A GaN device is packaged on a printed circuit board (PCB) with a vertical side of the device, and optionally the back side of the device, in thermal contact with the PCB. The packaging is compatible with surface mount technologies such as land grid array (LGA), ball grid array (BGA), and other formats. Thermal contact between the PCB and a vertical side of the device, and optionally the back side of the device, is made through solder. The solder used for the thermal contact may also connect a source terminal of the device, which also improves electrical stability of the device. The packaging is particularly suitable for GaN HEMT devices.
    Type: Grant
    Filed: January 22, 2019
    Date of Patent: March 2, 2021
    Inventors: Zhanming Li, Yan-Fei Liu, Yue Fu, Wai Tung Ng
  • Patent number: 10892254
    Abstract: Use of gallium nitride (GaN) semiconductor material for power devices is challenging due to low yield caused by high defect density on the wafer. Device layout on the wafer, chip probing, and device packaging increase the yield of large area power devices. Device dies containing a plurality of lower-power sub-devices are used to achieve high power ratings, by connecting only functional sub-devices together in the package, while being tolerant of defective sub-devices by selectively excluding the defective sub-devices. The packages and methods are particularly relevant to GaN power switching devices such as high electron mobility transistors (GaN HEMT).
    Type: Grant
    Filed: May 11, 2019
    Date of Patent: January 12, 2021
    Inventors: Zhanming Li, Guanhou Luo, Yue Fu, Wai Tung Ng, Yan-Fei Liu
  • Patent number: 10855273
    Abstract: A gate driver circuit for a gallium nitride (GaN) power transistor includes a RS-flipflop that receives a first pulse train at an S input terminal and a second pulse train at an R input terminal, and produces an output pulse train, and an amplifier that amplifies the output pulse train and produces a gate driver signal for the GaN power transistor. The RS-flipflop and the amplifier may be implemented together on a GaN monolithic integrated circuit, optionally together with the GaN power transistor. The GaN power transistor may be a high-side switch of a half-bridge circuit. The RS-flipflop may be implemented with enhancement mode and depletion mode GaN high electron mobility transistors (HEMTs). Embodiments avoid drawbacks of prior hybrid (e.g., silicon-GaN) approaches, such as parasitic inductances from bonding wires and on-board metal traces, especially at high operating frequencies, as well as reduce implementation cost and improve performance.
    Type: Grant
    Filed: May 27, 2019
    Date of Patent: December 1, 2020
    Inventors: Zhanming Li, Yan-Fei Liu, Yue Fu, Wai Tung Ng
  • Publication number: 20200357727
    Abstract: Packaging methods and structures for lateral high voltage gallium nitride (GaN) devices achieve electrical isolation while also maintaining thermal dissipation. The electrical isolation reduces or eliminates vertical leakage current, improving high voltage performance. The packages may use or be compatible standards such as JEDEC, which reduces packaging cost and facilitates implementation of the packaged devices in conventional circuit design approaches.
    Type: Application
    Filed: May 10, 2020
    Publication date: November 12, 2020
    Inventors: Zhanming Li, Yue Fu, Yan-Fei Liu
  • Patent number: 10686436
    Abstract: Voltage stabilizing and voltage regulating circuits implemented in GaN HEMT technology provide stable output voltages suitable for use in applications such as GaN power transistor gate drivers and low voltage auxiliary power supplies for GaN integrated circuits. Gate driver and voltage regulator modules include at least one GaN D-mode HEMT (DHEMT) and at least two GaN E-mode HEMTs (EHEMTs) connected together in series, so that the at least one DHEMT operates as a variable resistor and the at least two EHEMTs operate as a Zener diode that limits the output voltage. The gate driver and voltage regulator modules may be implemented as a GaN integrated circuits, and may be monolithically integrated together with other components such as amplifiers and power HEMTs on a single die to provide a GaN HEMT power module IC.
    Type: Grant
    Filed: June 27, 2019
    Date of Patent: June 16, 2020
    Inventors: Zhanming Li, Yue Fu, Yan-Fei Liu
  • Patent number: 10686411
    Abstract: Voltage stabilizing and voltage regulating circuits implemented in GaN HEMT technology provide stable output voltages suitable for use in applications such as GaN power transistor gate drivers and low voltage auxiliary power supplies for GaN integrated circuits. Gate driver and voltage regulator modules include at least one GaN D-mode HEMT (DHEMT) and at least two GaN E-mode HEMTs (EHEMTs) connected together in series, so that the at least one DHEMT operates as a variable resistor and the at least two EHEMTs operate as a Zener diode that limits the output voltage. The gate driver and voltage regulator modules may be implemented as a GaN integrated circuits, and may be monolithically integrated together with other components such as amplifiers and power HEMTs on a single die to provide a GaN HEMT power module IC.
    Type: Grant
    Filed: June 22, 2019
    Date of Patent: June 16, 2020
    Inventors: Zhanming Li, Yue Fu, Yan-Fei Liu
  • Patent number: 10615094
    Abstract: Described herein are semiconductor devices and structures with improved power handling and heat dissipation. Embodiments are suitable for implementation in gallium nitride. Devices may be provided as individual square or diamond-shaped dies having electrode terminals at the die corners, tapered electrode bases, and interdigitated electrode fingers. Device matrix structures include a plurality of device dies arranged on a substrate in a matrix configuration with interdigitated conductors. Device lattice structures are based on a unit cell comprising a plurality of individual devices, the unit cells disposed on a chip with geometric periodicity. Also described herein are methods for implementing the semiconductor devices and structures.
    Type: Grant
    Filed: December 30, 2017
    Date of Patent: April 7, 2020
    Inventors: Zhanming Li, Yue Fu, Wai Tung Ng, Yan-Fei Liu
  • Patent number: 10586749
    Abstract: Described herein are semiconductor devices and structures with improved power handling and heat dissipation. Embodiments are suitable for implementation in gallium nitride. Devices may be provided as individual square or diamond-shaped dies having electrode terminals at the die corners, tapered electrode bases, and interdigitated electrode fingers. Device matrix structures include a plurality of device dies arranged on a substrate in a matrix configuration with interdigitated conductors. Device lattice structures are based on a unit cell comprising a plurality of individual devices, the unit cells disposed on a chip with geometric periodicity. Also described herein are methods for implementing the semiconductor devices and structures.
    Type: Grant
    Filed: April 23, 2018
    Date of Patent: March 10, 2020
    Inventors: Zhanming Li, Yue Fu, Wai Tung Ng, Yan-Fei Liu
  • Publication number: 20200007091
    Abstract: Voltage stabilizing and voltage regulating circuits implemented in GaN HEMT technology provide stable output voltages suitable for use in applications such as GaN power transistor gate drivers and low voltage auxiliary power supplies for GaN integrated circuits. Gate driver and voltage regulator modules include at least one GaN D-mode HEMT (DHEMT) and at least two GaN E-mode HEMTs (EHEMTs) connected together in series, so that the at least one DHEMT operates as a variable resistor and the at least two EHEMTs operate as a Zener diode that limits the output voltage. The gate driver and voltage regulator modules may be implemented as a GaN integrated circuits, and may be monolithically integrated together with other components such as amplifiers and power HEMTs on a single die to provide a GaN HEMT power module IC.
    Type: Application
    Filed: June 22, 2019
    Publication date: January 2, 2020
    Inventors: Zhanming Li, Yue Fu, Yan-Fei Liu
  • Publication number: 20200007119
    Abstract: Voltage stabilizing and voltage regulating circuits implemented in GaN HEMT technology provide stable output voltages suitable for use in applications such as GaN power transistor gate drivers and low voltage auxiliary power supplies for GaN integrated circuits. Gate driver and voltage regulator modules include at least one GaN D-mode HEMT (DHEMT) and at least two GaN E-mode HEMTs (EHEMTs) connected together in series, so that the at least one DHEMT operates as a variable resistor and the at least two EHEMTs operate as a Zener diode that limits the output voltage. The gate driver and voltage regulator modules may be implemented as a GaN integrated circuits, and may be monolithically integrated together with other components such as amplifiers and power HEMTs on a single die to provide a GaN HEMT power module IC.
    Type: Application
    Filed: June 27, 2019
    Publication date: January 2, 2020
    Inventors: Zhanming Li, Yue Fu, Yan-Fei Liu
  • Publication number: 20190379374
    Abstract: A gate driver circuit for a gallium nitride (GaN) power transistor includes a RS-flipflop that receives a first pulse train at an S input terminal and a second pulse train at an R input terminal, and produces an output pulse train, and an amplifier that amplifies the output pulse train and produces a gate driver signal for the GaN power transistor. The RS-flipflop and the amplifier may be implemented together on a GaN monolithic integrated circuit, optionally together with the GaN power transistor. The GaN power transistor may be a high-side switch of a half-bridge circuit. The RS-flipflop may be implemented with enhancement mode and depletion mode GaN high electron mobility transistors (HEMTs). Embodiments avoid drawbacks of prior hybrid (e.g., silicon-GaN) approaches, such as parasitic inductances from bonding wires and on-board metal traces, especially at high operating frequencies, as well as reduce implementation cost and improve performance.
    Type: Application
    Filed: May 27, 2019
    Publication date: December 12, 2019
    Inventors: Zhanming Li, Yan-Fei Liu, Yue Fu, Wai Tung Ng
  • Publication number: 20190378822
    Abstract: Use of gallium nitride (GaN) semiconductor material for power devices is challenging due to low yield caused by high defect density on the wafer. Device layout on the wafer, chip probing, and device packaging increase the yield of large area power devices. Device dies containing a plurality of lower-power sub-devices are used to achieve high power ratings, by connecting only functional sub-devices together in the package, while being tolerant of defective sub-devices by selectively excluding the defective sub-devices. The packages and methods are particularly relevant to GaN power switching devices such as high electron mobility transistors (GaN HEMT).
    Type: Application
    Filed: May 11, 2019
    Publication date: December 12, 2019
    Inventors: Zhanming Li, Guanhou Luo, Yue Fu, Wai Tung Ng, Yan-Fei Liu
  • Patent number: 10388743
    Abstract: This invention relates to interdigitated electrodes for power electronic and optoelectronic devices where field and current distribution determine the device performance. Described are geometries based on rounded asymmetrical fingers and electrode bases of varying width. Simulations demonstrate benefits for reducing self-heating and thermal power loss, which reduces overall on-state resistance and increases reverse break down voltages.
    Type: Grant
    Filed: October 13, 2017
    Date of Patent: August 20, 2019
    Inventors: Zhanming Li, Yue Fu, Wai Tung Ng, Yan-Fei Liu
  • Publication number: 20190246499
    Abstract: A packaged GaN semiconductor device with improved heat dissipation is provided. A GaN device is packaged on a printed circuit board (PCB) with a vertical side of the device, and optionally the back side of the device, in thermal contact with the PCB. The packaging is compatible with surface mount technologies such as land grid array (LGA), ball grid array (BGA), and other formats. Thermal contact between the PCB and a vertical side of the device, and optionally the back side of the device, is made through solder. The solder used for the thermal contact may also connect a source terminal of the device, which also improves electrical stability of the device. The packaging is particularly suitable for GaN HEMT devices.
    Type: Application
    Filed: January 22, 2019
    Publication date: August 8, 2019
    Inventors: Zhanming Li, Yan-Fei Liu, Yue Fu, Wai Tung Ng
  • Patent number: 10135359
    Abstract: A hybrid rectifier that works as either a hybrid full bridge or a voltage doubler. Under 220 V AC input condition, the hybrid rectifier operates in full bridge mode, while at 110 V AC input, it operates as voltage doubler rectifier. The hybrid rectifier may be used with a DC-DC converter, such as an LLC resonant converter, in a power supply. With this mode switching, the LLC converter resonant tank design only takes consideration of 220 V AC input case, such that the required operational input voltage range is reduced, and the efficiency of the LLC converter is optimized. Both the size and power loss are reduced by using a single stage structure instead of the conventional two-stage configuration.
    Type: Grant
    Filed: April 25, 2018
    Date of Patent: November 20, 2018
    Inventors: Yang Chen, Hongliang Wang, Yan-Fei Liu, Zhanming Li, Yue Fu
  • Patent number: 10116233
    Abstract: A hybrid rectifier that works as either a hybrid full bridge or a voltage doubler. Under 220 V AC input condition, the hybrid rectifier operates in full bridge mode, while at 110 V AC input, it operates as voltage doubler rectifier. The hybrid rectifier may be used with a DC-DC converter, such as an LLC resonant converter, in a power supply. With this mode switching, the LLC converter resonant tank design only takes consideration of 220 V AC input case, such that the required operational input voltage range is reduced, and the efficiency of the LLC converter is optimized. Both the size and power loss are reduced by using a single stage structure instead of the conventional two-stage configuration.
    Type: Grant
    Filed: February 1, 2018
    Date of Patent: October 30, 2018
    Inventors: Yang Chen, Hongliang Wang, Yan-Fei Liu, Zhanming Li, Yue Fu
  • Publication number: 20180247879
    Abstract: Described herein are semiconductor devices and structures with improved power handling and heat dissipation. Embodiments are suitable for implementation in gallium nitride. Devices may be provided as individual square or diamond-shaped dies having electrode terminals at the die corners, tapered electrode bases, and interdigitated electrode fingers. Device matrix structures include a plurality of device dies arranged on a substrate in a matrix configuration with interdigitated conductors. Device lattice structures are based on a unit cell comprising a plurality of individual devices, the unit cells disposed on a chip with geometric periodicity. Also described herein are methods for implementing the semiconductor devices and structures.
    Type: Application
    Filed: April 23, 2018
    Publication date: August 30, 2018
    Inventors: Zhanming Li, Yue Fu, Wai Tung Ng, Yan-Fei Liu