Patents by Inventor Chiawei Liao

Chiawei Liao 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: 9629214
    Abstract: The present invention discloses a backlight control circuit with flexible configuration, comprising: a light emitting device path; a current source for controlling the current amount on the light emitting device path, the current source receiving a relatively high reference voltage in a first state, and receiving a relatively low reference voltage in a second state; and a current source control circuit for controlling the current source, whereby when the light emitting device path is in normal use, the current source is set to the first state, and when the light emitting device path is not in normal use, the current source is set to the second state.
    Type: Grant
    Filed: May 20, 2015
    Date of Patent: April 18, 2017
    Assignee: RICHTEK TECHNOLOGY CORPORATION
    Inventors: Chiawei Liao, Jing-Meng Liu
  • Patent number: 9179517
    Abstract: The present invention discloses a backlight control circuit, comprising: a voltage supply circuit for receiving an input voltage and generating an output voltage under control by a control signal; at least one voltage comparison path respectively coupled to at least one light emission device path; a voltage operative amplifier circuit for generating the control signal according to a lowest voltage on the at least one voltage comparison path; and at least one under current detection circuit for detecting whether a corresponding one of the at least one light emission device path is in an under current status, whereby when anyone of the under current detection circuits detects the under current status, it sends an exclusion signal excluding a corresponding one of the at least one voltage comparison path from being an effective input of the voltage operative amplifier.
    Type: Grant
    Filed: August 13, 2013
    Date of Patent: November 3, 2015
    Assignee: RICHTEK TECHNOLOGY CORPORATION
    Inventors: Chiawei Liao, Jing-Meng Liu
  • Publication number: 20150257228
    Abstract: The present invention discloses a backlight control circuit with flexible configuration, comprising: a light emitting device path; a current source for controlling the current amount on the light emitting device path, the current source receiving a relatively high reference voltage in a first state, and receiving a relatively low reference voltage in a second state; and a current source control circuit for controlling the current source, whereby when the light emitting device path is in normal use, the current source is set to the first state, and when the light emitting device path is not in normal use, the current source is set to the second state.
    Type: Application
    Filed: May 20, 2015
    Publication date: September 10, 2015
    Applicant: RICHTEK TECHNOLOGY CORPORATION
    Inventors: Chiawei Liao, Jing-Meng Liu
  • Patent number: 9072137
    Abstract: The present invention discloses a backlight control circuit with flexible configuration, comprising: a light emitting device path; a current source for controlling the current amount on the light emitting device path, the current source receiving a relatively high reference voltage in a first state, and receiving a relatively low reference voltage in a second state; and a current source control circuit for controlling the current source, whereby when the light emitting device path is in normal use, the current source is set to the first state, and when the light emitting device path is not in normal use, the current source is set to the second state.
    Type: Grant
    Filed: January 14, 2008
    Date of Patent: June 30, 2015
    Assignee: RICHTEK TECHNOLOGY CORPORATION
    Inventors: Chiawei Liao, Jing-Meng Liu
  • Patent number: 8941325
    Abstract: The present invention discloses a current splitter circuit for splitting a supply current to multiple light emitting device strings of a light emitting device array. The current splitter circuit includes: a minimum selector circuit coupled to the multiple light emitting device strings to generate a minimum signal which indicates a minimum voltage of the light emitting device strings; and multiple current source circuits each including a first current source end coupled to a corresponding light emitting device string, a second current source end coupled to ground, and a current source control end receiving a current control signal related to the minimum signal, so as to control currents through the corresponding light emitting device string.
    Type: Grant
    Filed: September 6, 2011
    Date of Patent: January 27, 2015
    Assignee: Richtek Technologies Corporation, R.O.C.
    Inventors: Jing-Meng Liu, Chiawei Liao
  • Patent number: 8853960
    Abstract: The present invention discloses a dimming control circuit and a method for generating analog and digital signals according to an analog control signal. The dimming control circuit according to the present invention comprises an input for receiving an analog control signal; a digital dimming circuit for receiving the analog control signal and generating a digital signal; an analog dimming circuit for receiving the analog control signal and generating an analog signal; and a power circuit enabled by the digital signal for converting a supply voltage to an output voltage according to the analog signal generated by the analog dimming circuit.
    Type: Grant
    Filed: October 8, 2008
    Date of Patent: October 7, 2014
    Assignee: Richtek Technology Corporation, R.O.C.
    Inventors: Chiawei Liao, Hsin-Kai Chiang
  • Publication number: 20140009075
    Abstract: The present invention discloses a backlight control circuit, comprising: a voltage supply circuit for receiving an input voltage and generating an output voltage under control by a control signal; at least one voltage comparison path respectively coupled to at least one light emission device path; a voltage operative amplifier circuit for generating the control signal according to a lowest voltage on the at least one voltage comparison path; and at least one under current detection circuit for detecting whether a corresponding one of the at least one light emission device path is in an under current status, whereby when anyone of the under current detection circuits detects the under current status, it sends an exclusion signal excluding a corresponding one of the at least one voltage comparison path from being an effective input of the voltage operative amplifier.
    Type: Application
    Filed: August 13, 2013
    Publication date: January 9, 2014
    Applicant: RICHTEK TECHNOLOGY CORPORATION
    Inventors: Chiawei Liao, Jing-Meng Liu
  • Patent number: 8508464
    Abstract: The present invention discloses a backlight control circuit capable of distinguishing an under current condition, comprising: at least one light emission device path having a voltage node; at least one current source for controlling the current amount on the light emission device path; and at least one under current detection circuit for generating a first control signal according to the voltage at the voltage node, wherein when the first control signal changes its state, the under current detection circuit generates a second control signal to change the voltage on the voltage node if the light emission device path is normally connected.
    Type: Grant
    Filed: January 14, 2008
    Date of Patent: August 13, 2013
    Assignee: Richtek Technology Corporation
    Inventors: Chiawei Liao, Xiaoyong Zhang, Jing-Meng Liu
  • Patent number: 8319444
    Abstract: The present invention discloses a tail-less LED control circuit, which includes: a power supply stage having an output terminal which provides electrical power to an LED circuit; an output capacitor coupled to the output terminal; an LED driver circuit coupled to the power supply stage for controlling the power supply stage to provide the electrical power to the LED circuit, the LED driver circuit receiving a PWM dimming signal for adjusting brightness of the LED circuit; and a MOSFET switch coupled to the output capacitor in series, the MOSFET switch switching synchronously with the PWM dimming signal to alleviate LED afterglow, wherein the MOSFET switch includes a body diode having an anode-cathode direction against the discharge direction of the output capacitor.
    Type: Grant
    Filed: May 26, 2010
    Date of Patent: November 27, 2012
    Assignee: Richtek Technology Corporation, R.O.C.
    Inventors: Chiawei Liao, Jing-Meng Liu, Leng-Nien Hsiu
  • Publication number: 20110316424
    Abstract: The present invention discloses a backlight control circuit, comprising: a voltage supply circuit for receiving an input voltage and generating an output voltage under control by a control signal; at least one voltage comparison path respectively coupled to at least one light emission device path; a voltage operative amplifier circuit for generating the control signal according to a lowest voltage on the at least one voltage comparison path; and at least one under current detection circuit for detecting whether a corresponding one of the at least one light emission device path is in an under current status, whereby when anyone of the under current detection circuits detects the under current status, it sends an exclusion signal excluding a corresponding one of the at least one voltage comparison path from being an effective input of the voltage operative amplifier.
    Type: Application
    Filed: September 7, 2011
    Publication date: December 29, 2011
    Inventors: CHIAWEI LIAO, JING-MENG LIU
  • Patent number: 8044920
    Abstract: The present invention discloses a backlight control circuit, and a method for controlling light emission devices. The method comprises: providing a plurality of light emission device paths connected in parallel; and setting a total current of the paths connected in parallel to a constant.
    Type: Grant
    Filed: October 2, 2007
    Date of Patent: October 25, 2011
    Assignee: Richtek Technology Corporation
    Inventors: Chiawei Liao, Jing-Meng Liu
  • Patent number: 8035606
    Abstract: The present invention discloses a backlight control circuit, comprising: a voltage supply circuit for receiving an input voltage and generating an output voltage under control by a control signal; at least one voltage comparison path respectively coupled to at least one light emission device path; a voltage operative amplifier circuit for generating the control signal according to a lowest voltage on the at least one voltage comparison path; and at least one under current detection circuit for detecting whether a corresponding one of the at least one light emission device path is in an under current status, whereby when anyone of the under current detection circuits detects the under current status, it sends an exclusion signal excluding a corresponding one of the at least one voltage comparison path from being an effective input of the voltage operative amplifier.
    Type: Grant
    Filed: October 2, 2007
    Date of Patent: October 11, 2011
    Assignee: Richtek Technology Corporation
    Inventors: Chiawei Liao, Jing-Meng Liu
  • Patent number: 8026676
    Abstract: The present invention discloses a dimming control circuit, comprising: an input terminal for receiving an input signal; an analog and digital dimming circuit receiving the input signal, wherein the analog and digital dimming circuit provides an analog dimming function when a voltage level of the input signal is between a predetermined lower limit and a predetermined upper limit, and a digital dimming function when the voltage level of the input signal switches above and below the predetermined lower limit, and wherein the analog and digital dimming circuit generates an analog signal when the voltage level of the input signal is above the predetermined lower limit; and a power circuit for supplying an output current in correspondence to the analog signal generated by the analog and digital dimming circuit.
    Type: Grant
    Filed: December 4, 2008
    Date of Patent: September 27, 2011
    Assignee: Richtek Technology Corporation, R.O.C.
    Inventors: Jing-Meng Liu, Chiawei Liao, Leng-Nien Hsiu
  • Publication number: 20100301761
    Abstract: The present invention discloses a tail-less LED control circuit, which includes: a power supply stage having an output terminal which provides electrical power to an LED circuit; an output capacitor coupled to the output terminal; an LED driver circuit coupled to the power supply stage for controlling the power supply stage to provide the electrical power to the LED circuit, the LED driver circuit receiving a PWM dimming signal for adjusting brightness of the LED circuit; and a MOSFET switch coupled to the output capacitor in series, the MOSFET switch switching synchronously with the PWM dimming signal to alleviate LED afterglow, wherein the MOSFET switch includes a body diode having an anode-cathode direction against the discharge direction of the output capacitor.
    Type: Application
    Filed: May 26, 2010
    Publication date: December 2, 2010
    Inventors: Chiawei Liao, Jing-Meng Liu, Leng-Nien Hsiu
  • Publication number: 20100084991
    Abstract: The present invention discloses a dimming control circuit, comprising: an input terminal for receiving an input signal; an analog and digital dimming circuit receiving the input signal, wherein the analog and digital dimming circuit provides an analog dimming function when a voltage level of the input signal is between a predetermined lower limit and a predetermined upper limit, and a digital dimming function when the voltage level of the input signal switches above and below the predetermined lower limit, and wherein the analog and digital dimming circuit generates an analog signal when the voltage level of the input signal is above the predetermined lower limit; and a power circuit for supplying an output current in correspondence to the analog signal generated by the analog and digital dimming circuit.
    Type: Application
    Filed: December 4, 2008
    Publication date: April 8, 2010
    Inventors: Jing-Meng Liu, Chiawei Liao, Leng-Nien Hsiu
  • Patent number: 7656142
    Abstract: Controlled compensation for a switching regulator is attained by detecting switching duty cycle of the switching regulator, developing a compensation signal having a time duration that is related to the detected switching duty cycle percentage, and generating a duty cycle control signal for the regulator that is dependent in part on the developed compensation signal.
    Type: Grant
    Filed: July 14, 2005
    Date of Patent: February 2, 2010
    Assignee: Linear Technology Corporation
    Inventor: Chiawei Liao
  • Publication number: 20090140666
    Abstract: The present invention discloses a dimming control circuit and a method for generating analog and digital signals according to an analog control signal. The dimming control circuit according to the present invention comprises an input for receiving an analog control signal; a digital dimming circuit for receiving the analog control signal and generating a digital signal; an analog dimming circuit for receiving the analog control signal and generating an analog signal; and a power circuit enabled by the digital signal for converting a supply voltage to an output voltage according to the analog signal generated by the analog dimming circuit.
    Type: Application
    Filed: October 8, 2008
    Publication date: June 4, 2009
    Inventors: Chiawei Liao, Hsin-Kai Chiang
  • Patent number: 7518351
    Abstract: Output voltage overshoot of a switching regulator is controlled by deactivating switching operation when a signal proportional to the output voltage exceeds a variable threshold level, with the threshold level set as a function of regulator output current. In accordance with an embodiment, a difference signal is generated that corresponds to a difference between an output voltage feedback signal and a constant reference voltage. The generated difference signal is combined with a signal proportional to load current to obtain an adapted threshold level. The adapted threshold level is greater than the level of the constant reference voltage. A regulator switch is reset to an off state when the output voltage feedback signal exceeds the adapted threshold level.
    Type: Grant
    Filed: May 18, 2005
    Date of Patent: April 14, 2009
    Assignee: Linear Technology Corporation
    Inventors: Chiawei Liao, Robert C. Dobkin
  • Publication number: 20080180386
    Abstract: The present invention discloses a backlight control circuit capable of distinguishing an under current condition, comprising: at least one light emission device path having a voltage node; at least one current source for controlling the current amount on the light emission device path; and at least one under current detection circuit for generating a first control signal according to the voltage at the voltage node, wherein when the first control signal changes its state, the under current detection circuit generates a second control signal to change the voltage on the voltage node if the light emission device path is normally connected.
    Type: Application
    Filed: January 14, 2008
    Publication date: July 31, 2008
    Inventors: Chiawei Liao, Xiaoyong Zhang, Jing-Meng Liu
  • Publication number: 20080180387
    Abstract: The present invention discloses a backlight control circuit with flexible configuration, comprising: a light emitting device path; a current source for controlling the current amount on the light emitting device path, the current source receiving a relatively high reference voltage in a first state, and receiving a relatively low reference voltage in a second state; and a current source control circuit for controlling the current source, whereby when the light emitting device path is in normal use, the current source is set to the first state, and when the light emitting device path is not in normal use, the current source is set to the second state.
    Type: Application
    Filed: January 14, 2008
    Publication date: July 31, 2008
    Inventors: Chiawei Liao, Jing-Meng Liu