Patents by Inventor Kuan-Hua Chao

Kuan-Hua Chao 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).

  • Patent number: 7994828
    Abstract: A frequency divider reduces jitter and power consumption, and includes a phase selector for receiving a plurality of clock signals and outputting an intermediate signal corresponding to phase characteristic of at least one of the clock signals, and an adjustable delay circuit for receiving the intermediate signal and generating an output signal by delaying the received intermediate signal.
    Type: Grant
    Filed: May 7, 2009
    Date of Patent: August 9, 2011
    Assignee: Mediatek Inc.
    Inventors: Hong-Sing Kao, Meng-Ta Yang, Kuan-Hua Chao, Tse-Hsiang Hsu
  • Patent number: 7936180
    Abstract: The invention provides a serial link transmitter coupled to a serial link receiver through a pair of transmission lines and having a pair of transmitting terminals respectively coupled to one of the transmission lines. The serial link transmitter comprises a differential amplifier and a voltage clamping circuit. The differential amplifier generates a pair of differential output voltages on the transmitting terminals according to a pair of differential input voltages for transmitting data to the serial link receiver, and the differential output voltages are transmitted with a common mode voltage to the serial link receiver during data transmission. The voltage clamping circuit clamps the pair of differential output voltages of the transmitting terminals to the common mode voltage before the serial link transmitter transmits data to the serial link receiver.
    Type: Grant
    Filed: November 6, 2008
    Date of Patent: May 3, 2011
    Assignee: Mediatek Inc.
    Inventors: Kuan-Hua Chao, Chih-Chien Hung, Pao-Cheng Chiu
  • Patent number: 7932740
    Abstract: A driving circuit includes: a first reference current source injects a reference current; each first switch unit is coupled between the first reference current source and one of first and second output ports; a second reference current source sinks the reference current; each second switch unit is coupled between the second reference current source and one of the output ports; a load unit is coupled between the output ports, and a common voltage is applied onto the load unit; and a calibration module calibrates an impedance of the load unit according to a voltage at one of the output ports, and the voltage is generated due to the reference current passing through one of the first switch units, the load unit, and one of the second switch units.
    Type: Grant
    Filed: August 6, 2008
    Date of Patent: April 26, 2011
    Assignee: Mediatek Inc.
    Inventors: Kuan-Hua Chao, Jeng-Horng Tsai, Tse-Hsiang Hsu
  • Publication number: 20100332887
    Abstract: One exemplary storage control device for a storage medium includes a controller and a voltage detector, where the controller controls data access of the storage medium, and the voltage detector monitors a power signal and asserts a detection signal to notify the controller when anomaly of the power signal is detected. Another exemplary storage control device for a storage medium includes a voltage detector and a controller, where the voltage detector monitors a power signal to generate a detection signal, and the controller controls data access of the storage medium. In addition, the controller enters a first operational state when the detection signal indicates that a voltage level of the power signal falls within a first voltage range, and enters a second operational state when the detection signal indicates that the voltage level of the power signal falls within a second voltage range.
    Type: Application
    Filed: March 19, 2010
    Publication date: December 30, 2010
    Inventors: Tzu-Chieh Lin, Tzu-Li Hung, Kuan-Hua Chao, Shiue-Shin Liu, Hong-Ching Chen, Li-Chun Tu
  • Patent number: 7706238
    Abstract: A laser power control system and related method for reducing a settling time in a target laser power transition are disclosed. The laser power control system includes a state decision circuit, for generating a state decision signal according to a selected operational state of a target circuit; a plurality of buffers, for storing a plurality of control data corresponding to a plurality of candidate operational states of the target circuit respectively; and a multiplexer, coupled between the state decision circuit and the buffers, for coupling a selected buffer of the buffers and the target circuit according to the state decision signal for outputting a control datum stored in the selected buffer to the target circuit.
    Type: Grant
    Filed: June 5, 2007
    Date of Patent: April 27, 2010
    Assignee: Mediatek Inc.
    Inventors: Ming-Jiou Yu, Chun-Yu Lin, Kuo-Jung Lan, Kuan-Hua Chao, Chia-Wei Liao, Chih-Ching Chen, Shu-Hung Chou, Jong-Woei Chen
  • Patent number: 7697399
    Abstract: A method for controlling a specific output power level emitted from a laser diode (LD) in an optical pick-up head unit (OPU) is disclosed. The LD is configured to provide a plurality of output power levels for accessing/recording an optical disc. The method includes: determining a specific power control value according to a first output power level, a second output power level, a first power control value of the first output power level, and the specific output power level, wherein the first output power level is less than the specific output power level and greater than the second output power level; and driving the LD to emit the specific output power level according to the specific power control value, the first power control value, and a second power control value of the second output power level.
    Type: Grant
    Filed: June 5, 2007
    Date of Patent: April 13, 2010
    Assignee: Mediatek Inc.
    Inventors: Ming-Jiou Yu, Chih-Ching Chen, Chia-Wei Liao, Kuo-Jung Lan, Bing-Yu Hsieh, Shu-Hung Chou, Kuan-Hua Chao, Jong-Woei Chen
  • Publication number: 20090296870
    Abstract: A clock generation circuit for a transmitter which transmits data according to an output clock signal is provided. The clock generation circuit include a clock generator and a phase locked loop (PLL). The clock generator generates a first clock signal. The PLL initially generates the output clock signal according to the first clock signal. When a frequency of the output clock signal generated according to the first clock signal is not within a range required for specification of the transmitter, the PLL switches to generate the output clock signal according to a second clock signal.
    Type: Application
    Filed: March 25, 2009
    Publication date: December 3, 2009
    Applicant: MEDIATEK INC.
    Inventors: Kuan-Hua Chao, Shiue-Shin Liu, Tse-Hsiang Hsu
  • Publication number: 20090296869
    Abstract: A clock generation circuit is provided and includes a phase locked loop (PLL) and a calibrator. The PLL is arranged to receive a first clock signal and generate the output clock signal. The PLL adjusts the frequency of the output clock signal according to a control signal. The calibrator is arranged to receive the output clock signal and a second clock signal, execute a frequency calibration between the output clock signal and the second clock signal, and generate the control signal according to results of the frequency calibration.
    Type: Application
    Filed: March 19, 2009
    Publication date: December 3, 2009
    Applicant: MEDIATEK INC.
    Inventors: Kuan-Hua Chao, Shiue-Shin Liu, Jeng-Horng Tsai, Chih-Ching Chen, Chuan Liu, Tse-Hsiang Hsu
  • Publication number: 20090278574
    Abstract: A frequency divider reduces jitter and power consumption, and includes a phase selector for receiving a plurality of clock signals and outputting an intermediate signal corresponding to phase characteristic of at least one of the clock signals, and an adjustable delay circuit for receiving the intermediate signal and generating an output signal by delaying the received intermediate signal.
    Type: Application
    Filed: May 7, 2009
    Publication date: November 12, 2009
    Inventors: Hong-Sing Kao, Meng-Ta Yang, Kuan-Hua Chao, Tse-Hsiang Hsu
  • Publication number: 20090195288
    Abstract: The invention provides a serial link transmitter coupled to a serial link receiver through a pair of transmission lines and having a pair of transmitting terminals respectively coupled to one of the transmission lines. The serial link transmitter comprises a differential amplifier and a voltage clamping circuit. The differential amplifier generates a pair of differential output voltages on the transmitting terminals according to a pair of differential input voltages for transmitting data to the serial link receiver, and the differential output voltages are transmitted with a common mode voltage to the serial link receiver during data transmission. The voltage clamping circuit clamps the pair of differential output voltages of the transmitting terminals to the common mode voltage before the serial link transmitter transmits data to the serial link receiver.
    Type: Application
    Filed: November 6, 2008
    Publication date: August 6, 2009
    Applicant: MEDIATEK INC.
    Inventors: Kuan-Hua Chao, Chih-Chien Hung, Pao-Cheng Chiu
  • Publication number: 20090184732
    Abstract: A driving circuit includes a pair of input ports, a pair of differential output ports, a first differential pair, a second differential pair, a load unit, and a current source. The first differential pair is directly connected to a first voltage level, and is coupled to the pair of input ports and the pair of differential output ports. The second differential pair is coupled to the pair of input ports and the pair of differential output ports. The load unit is coupled to the pair of differential output ports. The current source is coupled between the second differential pair and a second voltage level.
    Type: Application
    Filed: January 23, 2008
    Publication date: July 23, 2009
    Inventors: Kuan-Hua Chao, Tse-Hsiang Hsu
  • Publication number: 20090168943
    Abstract: A clock generation device provided for a transmitter is provided and comprises a clock generator, a calculator and a first phase locked loop (PLL) circuit. The clock generator generates a first clock signal. The calculator calculates a frequency difference between the first and second clock signals. The first PLL circuit generates an output clock signal according to a first reference clock signal related to the first clock signal, and a frequency of the output clock signal is changed according to the frequency difference. The transmitter transmits data according to the output clock signal.
    Type: Application
    Filed: December 5, 2008
    Publication date: July 2, 2009
    Applicant: MEDIATEK INC.
    Inventors: Kuan-Hua Chao, Chuan Liu, Tse-Hsiang Hsu
  • Publication number: 20080253492
    Abstract: A circuit for controlling a mixed mode controlled oscillator. The circuit comprises a charge pump, and a digital loop filter. The charge pump is coupled to the mixed mode controlled oscillator. The charge pump receives an up/down signal and sends a current signal to the mixed mode controlled oscillator. The digital loop filter receives the up/down signal and generates a digital code signal to the mixed mode controlled oscillator. An output frequency of the mixed mode controlled oscillator is controlled by the current signal and the digital code signal.
    Type: Application
    Filed: April 1, 2008
    Publication date: October 16, 2008
    Applicant: MEDIATEK INC.
    Inventors: Ping-Ying Wang, Kuan-Hua Chao, Jeng-Horng Tsai
  • Publication number: 20070280086
    Abstract: A laser power control system and related method for reducing a settling time in a target laser power transition are disclosed. The laser power control system includes a state decision circuit, for generating a state decision signal according to a selected operational state of a target circuit; a plurality of buffers, for storing a plurality of control data corresponding to a plurality of candidate operational states of the target circuit respectively; and a multiplexer, coupled between the state decision circuit and the buffers, for coupling a selected buffer of the buffers and the target circuit according to the state decision signal for outputting a control datum stored in the selected buffer to the target circuit.
    Type: Application
    Filed: June 5, 2007
    Publication date: December 6, 2007
    Inventors: Ming-Jiou Yu, Chun-Yu Lin, Kuo-Jung Lan, Kuan-Hua Chao, Chia-Wei Liao, Chih-Ching Chen, Shu-Hung Chou