Patents by Inventor Sang Y. Youn

Sang Y. Youn 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: 20150109279
    Abstract: An electronic device may be provided with an organic light-emitting diode display. The display may include row driver circuitry that provides an emission control signal at an output terminal to display pixels. The emission control signals may enable or disable light emission by the pixels. The row driver circuitry may include a bootstrapping capacitor that stores charge for boosting a gate signal at an intermediate node for a pull-up transistor above a power supply voltage. The row driver circuitry may include a pull-down transistor coupled to the intermediate node. The source terminal of the pull-down transistor may be coupled to the output terminal or an additional pull-down transistor may be stacked with the pull-down transistor to reduce leakage current. Charge pump circuitry may be coupled to the intermediate node to ensure that the intermediate node is maintained at a voltage above the power supply voltage.
    Type: Application
    Filed: October 1, 2014
    Publication date: April 23, 2015
    Inventors: Vasudha Gupta, Tsung-Ting Tsai, Jae Won Choi, Sang Y. Youn, Young Bae Park, Chin-Wei Lin
  • Publication number: 20150109276
    Abstract: An electronic device may be provided with an organic light-emitting diode display. The display may include row driver circuitry that provides an emission control signal at an output terminal to display pixels. The emission control signals may enable or disable light emission by the pixels. The row driver circuitry may include a bootstrapping capacitor that stores charge for boosting a gate signal at an intermediate node for a pull-up transistor above a power supply voltage. The row driver circuitry may include a pull-down transistor coupled to the intermediate node. The source terminal of the pull-down transistor may be coupled to the output terminal or an additional pull-down transistor may be stacked with the pull-down transistor to reduce leakage current. Charge pump circuitry may be coupled to the intermediate node to ensure that the intermediate node is maintained at a voltage above the power supply voltage.
    Type: Application
    Filed: June 26, 2014
    Publication date: April 23, 2015
    Inventors: Vasudha Gupta, Tsung-Ting Tsai, Jae Won Choi, Sang Y. Youn, Young Bae Park
  • Patent number: 8970464
    Abstract: The present disclosure is directed to systems and methods for determining sheet resistance values in a liquid crystal display (LCD) panel. In certain embodiments, a system for determining sheet resistance values in an LCD panel may include a display driver integrated circuit (IC). The display driver IC may include a first switch coupled to a first input/output (I/O) pad and a second I/O pad such that the first I/O pad is configured to couple to a voltage source and the second I/O pad is configured to couple to a current source. The display driver IC may also include a second switch coupled to a third I/O pad and the second I/O pad such that the second switch has substantially the same geometry as the first switch and the third I/O pad is configured to couple to a thin-film transistor (TFT) layer of the display panel.
    Type: Grant
    Filed: August 31, 2012
    Date of Patent: March 3, 2015
    Assignee: Appl Inc.
    Inventors: Kingsuk Brahma, Saman Saeedi, Sang Y. Youn, Shafiq M Jamal, Taif A. Syed
  • Patent number: 8890545
    Abstract: Better performance can be provided for a display system that has semiconductor microelectronic components such as demultiplexors, gate line and data line drivers, and pixel switches formed on the display substrate, e.g., a glass substrate that constitutes part of an active matrix display panel. A gate source capacitance of a constituent transistor of one of these microelectronic components, e.g., a pixel thin film transistor (TFT) that is part of a particular display element, may be measured using a replica component that emulates the behavior of the component.
    Type: Grant
    Filed: September 11, 2012
    Date of Patent: November 18, 2014
    Assignee: Apple Inc.
    Inventors: Shafiq M. Jamal, Hopil Bae, Sang Y Youn, Wei H. Yao
  • Publication number: 20140139415
    Abstract: Systems and methods for efficiently generating display driver timing signals are provided. In one example, display driver circuitry of an electronic display may provide a negative voltage from a negative voltage supply to display control circuitry during a first period and may provide a positive voltage from a positive voltage supply to the display control circuitry during a second period. After providing the negative voltage during the first period but before providing the positive voltage during the second period, the display driver circuitry may precharge the capacitance of the display control circuitry to ground. In this way, the positive voltage supply substantially does not supply charge to raise the voltage on the capacitance of the display control circuitry from the negative voltage to ground.
    Type: Application
    Filed: November 15, 2013
    Publication date: May 22, 2014
    Applicant: APPLE INC.
    Inventors: David A. Stronks, Hopil Bae, Kingsuk Brahma, Sang Y. Youn
  • Publication number: 20140132585
    Abstract: The present disclosure relates to devices and methods for reducing power consumption of a display. One electronic display includes a first switch coupled between a first gate of a first transistor and a second gate of a second transistor to selectively connect the first gate to the second gate. The display includes a second switch coupled between the second gate of the second transistor and a third gate of a third transistor to selectively connect the second gate to the third gate. The display also includes driving circuitry that controls the first switch to connect the first gate to the second gate to share a first charge between the first and second gates. The driving circuitry also controls the second switch to connect the second gate to the third gate to share a second charge between the second and third gates. Accordingly, power consumption of the display may be reduced.
    Type: Application
    Filed: May 9, 2013
    Publication date: May 15, 2014
    Applicant: Apple Inc
    Inventors: Sang Y. Youn, Hopil Bae, David A. Stronks, Kingsuk Brahma, Taif A. Syed
  • Publication number: 20140125645
    Abstract: A method for testing integrated circuit-to-substrate joints that electrically connect an IC to a substrate. An ammeter is coupled to a test node of the driver IC, while the test node is coupled to a current source, and a measured current output of the ammeter is recorded. A voltmeter is coupled to the test node while the test node is coupled to an end node of a group of dummy IC-to-substrate joints that are daisy chained; a first measured voltage output of the voltmeter is then recorded. The IC then couples the test node to another end node of the daisy chained dummy joints, and a second measured voltage output is recorded. A resistance or admittance value for the electrical connection of the IC to the substrate is then computed, using the first and second measured voltage outputs and the measured current output. Other embodiments are also described and claimed.
    Type: Application
    Filed: December 11, 2012
    Publication date: May 8, 2014
    Applicant: Apple Inc.
    Inventors: Mir B. Ghaderi, Shafiq M. Jamal, Sang Y. Youn
  • Publication number: 20140071111
    Abstract: An electronic display includes a display panel. The display panel includes a pixel array and receives a supply voltage. The display panel also includes a panel driver configured to generate a gate line voltage. The panel driver also supplies the gate line voltage to the display panel based on a comparison between the gate line voltage and the supply voltage.
    Type: Application
    Filed: November 9, 2012
    Publication date: March 13, 2014
    Applicant: APPLE INC.
    Inventors: Taif Ahmed Said, Kevin J. White, Sang Y. Youn
  • Publication number: 20140062845
    Abstract: The present disclosure is directed to systems and methods for determining sheet resistance values in a liquid crystal display (LCD) panel. In certain embodiments, a system for determining sheet resistance values in an LCD panel may include a display driver integrated circuit (IC). The display driver IC may include a first switch coupled to a first input/output (I/O) pad and a second I/O pad such that the first I/O pad is configured to couple to a voltage source and the second I/O pad is configured to couple to a current source. The display driver IC may also include a second switch coupled to a third I/O pad and the second I/O pa such that the second switch has substantially the same geometry as the first switch and the third I/O pad is configured to couple to a thin-film transistor (TFT) layer of the display panel.
    Type: Application
    Filed: August 31, 2012
    Publication date: March 6, 2014
    Applicant: APPLE INC.
    Inventors: Kingsuk Brahma, Saman Saeedi, Sang Y. Youn, Shafiq M. Jamal, Taif A. Syed
  • Patent number: 8653882
    Abstract: A charge pump driver circuit has a first charge switch that couples a first node of a flying capacitor to a first power supply node, and a second charge switch that couples a second node of the capacitor to a second power supply node. Control circuitry is coupled to open the second charge switch and discharge the second node of the capacitor, in response to a control signal. Other embodiments are also described and claimed.
    Type: Grant
    Filed: March 29, 2012
    Date of Patent: February 18, 2014
    Assignee: Apple Inc.
    Inventors: Taif A. Syed, Sang Y. Youn
  • Publication number: 20130328576
    Abstract: Better performance can be provided for a display system that has semiconductor microelectronic components such as demultiplexors, gate line and data line drivers, and pixel switches formed on the display substrate, e.g., a glass substrate that constitutes part of an active matrix display panel. A gate source capacitance of a constituent transistor of one of these microelectronic components, e.g., a pixel thin film transistor (TFT) that is part of a particular display element, may be measured using a replica component that emulates the behavior of the component.
    Type: Application
    Filed: September 11, 2012
    Publication date: December 12, 2013
    Applicant: Apple Inc.
    Inventors: Shafiq M. Jamal, Hopil Bae, Sang Y. Youn, Wei H. Yao
  • Publication number: 20130328852
    Abstract: Better performance can be provided for a display system that has semiconductor microelectronic components such as demultiplexors, gate line and data line drivers, and pixel switches formed on the display substrate, e.g., a glass substrate that constitutes part of an active matrix display panel. A threshold voltage of a constituent transistor of one of these microelectronic components, e.g., a pixel thin film transistor (TFT) that is part of a particular display element, may be measured using a replica component that emulates the behavior of the component.
    Type: Application
    Filed: September 11, 2012
    Publication date: December 12, 2013
    Applicant: Apple Inc.
    Inventors: Shafiq M. Jamal, Hopil Bae, Sang Y. Youn, Wei H. Yao
  • Publication number: 20130328846
    Abstract: Better performance can be provided for a display system that has semiconductor microelectronic components such as demultiplexors, gate line and data line drivers, and pixel switches formed on the display substrate, e.g., a glass substrate that constitutes part of an active matrix display panel. A constituent transistor of one of these microelectronic components, e.g., a pixel thin film transistor (TFT) that is part of a particular display element, may be characterized using a replica component that emulates the behavior of the component.
    Type: Application
    Filed: September 11, 2012
    Publication date: December 12, 2013
    Applicant: Apple Inc.
    Inventors: Shafiq M. Jamal, Hopil Bae, Sang Y. Youn, Wei H. Yao
  • Publication number: 20130328847
    Abstract: Methods and devices employing mura prevention circuitry, are provided. In one example, a method may include supplying a first voltage pathway between a common electrode driver and a common electrode of an electronic display device and supplying a second voltage pathway between the common electrode driver and ground. Mura prevention circuitry may be supplied that activates the first voltage pathway when the electronic display device is turned on and an activation gate signal is provided from a gate corresponding to the common electrode driver. Further, the mura prevention circuitry may activate the second voltage pathway when the electronic display device is turned off or no activation gate signal is provided from the gate corresponding to the common electrode driver.
    Type: Application
    Filed: October 17, 2012
    Publication date: December 12, 2013
    Applicant: APPLE INC.
    Inventors: Ahmad Al-Dahle, Hopil Bae, Sang Y. Youn, Yafei Bi, Wei H. Yao, David A. Stronks
  • Publication number: 20130328749
    Abstract: A display is disclosed that includes a transparent substrate and a plurality of pixel transistors that are formed on the transparent substrate to generate an image for display. A transistor drive circuit is used to drive the pixel transistors to generate the image. The transistor drive circuit may include a gate driver. Further, a test circuit may be used to: adjust voltages that are applied by the gate driver to a pixel transistor; and determine the voltage of the gate driver when a current spike has occurred to the pixel transistor which causes the pixel transistor to turn on. Once this threshold voltage for the gate driver to turn on the pixel transistor has been determined, it may be stored in a storage device for future use by the gate driver. Other embodiments are also described and claimed.
    Type: Application
    Filed: August 22, 2012
    Publication date: December 12, 2013
    Applicant: APPLE INC
    Inventors: Shafiq M. Jamal, Yafei Bi, Hopil Bae, Sang Y. Youn
  • Publication number: 20130257521
    Abstract: A charge pump driver circuit has a first charge switch that couples a first node of a flying capacitor to a first power supply node, and a second charge switch that couples a second node of the capacitor to a second power supply node. Control circuitry is coupled to open the second charge switch and discharge the second node of the capacitor, in response to a control signal. Other embodiments are also described and claimed.
    Type: Application
    Filed: March 29, 2012
    Publication date: October 3, 2013
    Applicant: Apple Inc.
    Inventors: Taif A. Syed, Sang Y. Youn