Patents by Inventor Wen-Hua Chang

Wen-Hua Chang 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: 20160098139
    Abstract: A touch system, a stylus, a touch apparatus, and a control method of the touch apparatus are provided. The control method includes following steps. At least one characteristic data of at least one input tool is obtained. An identifier of the input tool is generated according to the characteristic data. If a touch operation on the touch panel is performed with the input tool, a specific function of the touch apparatus is determined according to the identifier of the input tool.
    Type: Application
    Filed: July 23, 2015
    Publication date: April 7, 2016
    Inventors: Yao-Tsung Chang, Ching-Fu Hsu, Ming-Chih Chen, Kuo-Hsing Wang, Jui-Ta Hsieh, Chih-Chung Chiang, Wen-Hua Chang
  • Publication number: 20160087632
    Abstract: A current amplifier and a transmitter using the same. The current amplifier has a first and second transistor and a voltage level shifting unit. The first transistor has a gate receiving an input current and a drain receiving a driving current. The voltage level shifting unit providing a voltage shift is coupled between the drain of the first transistor and the gate of the second transistor. An output current is generated at the drain of the second transistor.
    Type: Application
    Filed: December 8, 2015
    Publication date: March 24, 2016
    Inventors: Tsun-Yuan FAN, Wen-Hua CHANG
  • Patent number: 9276597
    Abstract: An analog-to-digital converter is provided. Each pre-amplifier provides a pair of differential outputs according to a pair of differential analog input signals and a first reference voltage and a second reference voltage from a resistor chain, wherein the first reference voltage is different from the second reference voltage. Each dynamic comparator provides a first comparing signal and a second comparing signal according to the pair of differential outputs of the pre-amplifier. Each pre-amplifier includes a first calibration unit for calibrating a first offset voltage from the pre-amplifier at the pair of differential outputs at a specific temperature, and a second calibration unit for calibrating a second offset voltage from the corresponding dynamic comparator at the pair of differential outputs.
    Type: Grant
    Filed: February 10, 2015
    Date of Patent: March 1, 2016
    Assignee: MEDIATEK INC.
    Inventor: Wen-Hua Chang
  • Patent number: 9203423
    Abstract: A signal generation apparatus includes a digital-to-analog converter, a bias stage and a class AB output stage. The digital-to-analog converter is arranged for outputting a current as an input signal. The bias stage is coupled to the digital-to-analog converter, and is arranged for generating a bias signal according to at least the input signal. The class AB output stage is coupled to the bias stage, and is arranged for generating an output signal at an output node of the signal generation apparatus according to the bias signal, wherein the output signal includes a first signal component and a second signal component, both the first signal component and the second signal component correspond to the input signal, and there is a linear relation between the output signal and the input signal.
    Type: Grant
    Filed: August 22, 2013
    Date of Patent: December 1, 2015
    Assignee: MEDIATEK INC.
    Inventor: Wen-Hua Chang
  • Publication number: 20150258657
    Abstract: A grinding wheel includes a base disk, and a plurality of teeth protruding beyond a surface of the base disk. The plurality of teeth is aligned to an elongated ring encircling a center of the grinding wheel.
    Type: Application
    Filed: May 29, 2015
    Publication date: September 17, 2015
    Inventors: Chun-Hsing Su, Jing-Cheng Lin, Tsei-Chung Fu, Wen-Hua Chang, Yi-Chao Mao
  • Publication number: 20150193043
    Abstract: A touch input device including a carrying board, a plurality of first electrode pads, and a plurality of conductive lines is provided. The carrying board includes a plurality of cantilever portions and a plurality of connecting portions. The connecting portions are respectively connected to the cantilever portions. The first electrode pads are respectively disposed on the cantilever portions and configured to sense capacitance variation due to an object approaching or touching the carrying board. The conductive lines extend on the connecting portions and are respectively connected to the first electrode pads. A manufacturing method of a touch input device and a touch sensing method are also provided.
    Type: Application
    Filed: April 6, 2014
    Publication date: July 9, 2015
    Applicant: Wistron Corporation
    Inventors: Sweehan J.H. Yang, Tung-Yang Tang, Wen-Hua Chang, Yong-Yu Chen
  • Publication number: 20150054584
    Abstract: A signal generation apparatus includes a digital-to-analog converter, a bias stage and a class AB output stage. The digital-to-analog converter is arranged for outputting a current as an input signal. The bias stage is coupled to the digital-to-analog converter, and is arranged for generating a bias signal according to at least the input signal. The class AB output stage is coupled to the bias stage, and is arranged for generating an output signal at an output node of the signal generation apparatus according to the bias signal, wherein the output signal includes a first signal component and a second signal component, both the first signal component and the second signal component correspond to the input signal, and there is a linear relation between the output signal and the input signal.
    Type: Application
    Filed: August 22, 2013
    Publication date: February 26, 2015
    Applicant: MEDIATEK INC.
    Inventor: Wen-Hua Chang
  • Publication number: 20140361836
    Abstract: A current amplifier and a transmitter using the same. The current amplifier includes: a first transistor having a gate coupled to a former-stage circuit, a drain coupled to a current source, and a source biased at a constant voltage level; a second transistor having a gate coupled to the current source and having a source and a drain; a first impedance circuit coupled between the gate of the first transistor and the source of the second transistor; and a second impedance circuit coupled between the source of the second transistor and a ground terminal The current amplifier receives an input current from the former-stage circuit and generates an output current at the drain of the second transistor. Note that no current source is connected to the source of the first transistor.
    Type: Application
    Filed: June 5, 2013
    Publication date: December 11, 2014
    Inventors: Wen-Hua CHANG, Tsung-Yi CHOU
  • Patent number: 8836565
    Abstract: An analog to digital converter can operate in a sampling mode or in a comparing mode. The analog to digital converter comprises: a comparator; a first capacitor, comprising a first terminal coupled to a first input terminal of the comparator; a second capacitor; a first switch module; a control unit, for controlling the conductive states of the first switch module corresponding to the sampling mode or the comparing mode. The first capacitor samples a value of a first input signal and the second capacitor samples a value of a first reference signal via the first switch module in the sampling mode. The first capacitor and the second capacitor are not coupled to each other in the sampling mode. The first capacitor and the second capacitor are coupled in series via the first switch module in the comparing mode.
    Type: Grant
    Filed: September 27, 2013
    Date of Patent: September 16, 2014
    Assignee: Mediatek Inc.
    Inventor: Wen-Hua Chang
  • Patent number: 8285228
    Abstract: A signal transmitting circuit includes: a signal generating circuit arranged to generate an output signal to a loading device according to an input signal; an adjusting circuit; and a matching circuit having a first port coupled to the adjusting circuit and a second port coupled to the signal generating circuit, wherein the second port is arranged to couple to the loading device so as to provide a matching impedance corresponding to the loading device; and the adjusting circuit is arranged to generate an adjusting signal of which a voltage applied on the first port is substantially equal to a voltage of the output signal applied on the second port.
    Type: Grant
    Filed: April 12, 2010
    Date of Patent: October 9, 2012
    Assignee: Mediatek Inc.
    Inventor: Wen-Hua Chang
  • Patent number: 8222927
    Abstract: A reference buffer circuit is provided, comprising a reference buffering stage and a driving stage. The buffering stage provides a first driving voltage based on a first input voltage. The driving stage is driven by the first driving voltage to output a first output voltage. In the buffering stage, a first operational amplifier has a first input end for receiving the first input voltage, a second input end, and an output end for outputting a first tracking voltage. A first level shifter is coupled to the output end of the first operational amplifier, shifting a level of the first tracking voltage to generate the first driving voltage. A first buffering transistor has a drain coupled to a first supply voltage, a source connected to the second input end of the first operational amplifier, and a gate coupled to the first charge pump for receiving the first driving voltage.
    Type: Grant
    Filed: April 9, 2009
    Date of Patent: July 17, 2012
    Assignee: Mediatek Inc.
    Inventors: Chieh-Wei Liao, Wen Hua Chang, Tse-Hsiang Hsu
  • Patent number: 8111178
    Abstract: A capacitor array includes a plurality of capacitor components each having a first node and a second node, and first nodes of the capacitor components are coupled to each other. A calibration method for the capacitor array utilizes a calibration capacitor component to couple the first nodes. Then, the calibration method determines a capacitance indication value regarding the specific capacitor component by coupling different references voltage to a second node of the specific capacitor component and coupling different test voltages to a second node of the calibration capacitor component. Accordingly, the calibration method calibrates the capacitance mismatches of the capacitor array in the digital domain.
    Type: Grant
    Filed: November 26, 2009
    Date of Patent: February 7, 2012
    Assignee: Mediatek Inc.
    Inventors: Chieh-Wei Liao, Chia-Hua Chou, Tse-Hsiang Hsu, Wen-Hua Chang
  • Publication number: 20110249711
    Abstract: A signal transmitting circuit includes: a signal generating circuit arranged to generate an output signal to a loading device according to an input signal; an adjusting circuit; and a matching circuit having a first port coupled to the adjusting circuit and a second port coupled to the signal generating circuit, wherein the second port is arranged to couple to the loading device so as to provide a matching impedance corresponding to the loading device; and the adjusting circuit is arranged to generate an adjusting signal of which a voltage applied on the first port is substantially equal to a voltage of the output signal applied on the second port.
    Type: Application
    Filed: April 12, 2010
    Publication date: October 13, 2011
    Inventor: Wen-Hua Chang
  • Publication number: 20110122006
    Abstract: A capacitor array includes a plurality of capacitor components each having a first node and a second node, and first nodes of the capacitor components are coupled to each other. A calibration method for the capacitor array utilizes a calibration capacitor component to couple the first nodes. Then, the calibration method determines a capacitance indication value regarding the specific capacitor component by coupling different references voltage to a second node of the specific capacitor component and coupling different test voltages to a second node of the calibration capacitor component. Accordingly, the calibration method calibrates the capacitance mismatches of the capacitor array in the digital domain.
    Type: Application
    Filed: November 26, 2009
    Publication date: May 26, 2011
    Inventors: Chieh-Wei Liao, Chia-Hua Chou, Tse-Hsiang Hsu, Wen-Hua Chang
  • Publication number: 20100259303
    Abstract: A reference buffer circuit is provided, comprising a reference buffering stage and a driving stage. The buffering stage provides a first driving voltage based on a first input voltage. The driving stage is driven by the first driving voltage to output a first output voltage. In the buffering stage, a first operational amplifier has a first input end for receiving the first input voltage, a second input end, and an output end for outputting a first tracking voltage. A first level shifter is coupled to the output end of the first operational amplifier, shifting a level of the first tracking voltage to generate the first driving voltage. A first buffering transistor has a drain coupled to a first supply voltage, a source connected to the second input end of the first operational amplifier, and a gate coupled to the first charge pump for receiving the first driving voltage.
    Type: Application
    Filed: April 9, 2009
    Publication date: October 14, 2010
    Applicant: MEDIATEK INC.
    Inventors: Chieh-Wei Liao, Wen Hua Chang, Tse-Hsiang Hsu
  • Patent number: 7464258
    Abstract: Disclosed is a method of displaying foreground visual data in foreground and executing system booting in background for a computer system, including the following steps: a computer system detecting a pre-configured hot key being pressed; the computer system being activated and executing the BIOS; the BIOS loading and executing the monitor driver, and loading a default animation related to the applications associated with the pre-configured hot key; the monitor displaying the default animation while operating system being loaded and executed; and finally, after the initialization of the operating system, the application programs associated with the pre-configured hot key being loaded and executed.
    Type: Grant
    Filed: October 5, 2005
    Date of Patent: December 9, 2008
    Assignee: Mitac Technology Corp.
    Inventor: Wen-Hua Chang
  • Publication number: 20070022282
    Abstract: Disclosed is a method of displaying foreground visual data in foreground and executing system booting in background for a computer system, including the following steps: a computer system detecting a pre-configured hot key being pressed; the computer system being activated and executing the BIOS; the BIOS loading and executing the monitor driver, and loading a default animation related to the applications associated with the pre-configured hot key; the monitor displaying the default animation while operating system being loaded and executed; and finally, after the initialization of the operating system, the application programs associated with the pre-configured hot key being loaded and executed.
    Type: Application
    Filed: October 5, 2005
    Publication date: January 25, 2007
    Inventor: Wen-Hua Chang
  • Publication number: 20060065162
    Abstract: A dual functional desk with tilt-adjustable tops includes a stand frame; a front top mounted to an upper front portion of the stand frame via a front tilt control device; and a rear top including a screen support and mounted to an upper rear portion of the stand frame via a rear tilt control device. A computer, TV, or PDA screen may be mounted on the screen support, and the front and the rear top may be separately adjusted to different tilt angles best for writing, reading, or drawing at the front top, or watching the screen mounted on the rear top. When the screen is not in use, the front and the rear top may be simultaneously restored to a horizontal state or adjusted to the same plane with the screen invisibly located below the rear top to increase the usable area on the desk.
    Type: Application
    Filed: September 24, 2004
    Publication date: March 30, 2006
    Inventors: Yueh Chi, Wen-Hua Chang, Hungh-Hsiang Wang
  • Publication number: 20060065167
    Abstract: A desk with tilt-adjustable tops includes a stand frame; a front top mounted to an upper front portion of the stand frame via a front tilt control device; and a rear top mounted to an upper rear portion of the stand frame via a rear tilt control device. The stand frame is height-adjustable and has a storage box located below a rear portion of the front top. The front and the rear top may be separately adjusted to different tilt angles best for writing, drawing, or reading at the desk. In normal time, the front and the rear top may be simultaneously restored to a horizontal state or adjusted to the same plane with the storage box invisibly located below the front top, so that the desk is used as a general desk with a flat top.
    Type: Application
    Filed: September 24, 2004
    Publication date: March 30, 2006
    Inventors: Yueh Chi, Wen-Hua Chang, Hungh-Hsiang Wang
  • Publication number: 20060065166
    Abstract: A dual functional desk with tilt-adjustable tops includes a stand frame; a front top mounted to an upper front portion of the stand frame via a front tilt control device; and a rear top including a screen support and mounted to an upper rear portion of the stand frame via a rear tilt control device. A computer, TV, or PDA screen may be mounted on the screen support, and the front and the rear top may be separately adjusted to different tilt angles best for writing, reading, or drawing at the front top, or watching the screen mounted on the rear top. When the screen is not in use, the front and the rear top may be simultaneously restored to a horizontal state or adjusted to the same plane with the screen invisibly located below the rear top to increase the usable area on the desk.
    Type: Application
    Filed: September 30, 2004
    Publication date: March 30, 2006
    Inventors: Yueh Chi, Wen-Hua Chang, Hungh-Hsiang Wang