Patents by Inventor Weina ZHOU

Weina ZHOU 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).

  • Current-switching LED driver using DAC to ramp bypass currents to accelerate switching speed and reduce ripple
    Patent number: 8581519
    Abstract: A light-emitting diode (LED) driver provides faster rise and fall times for LED current to reduce image sticking and other interference. A standard DC-DC converter provides a sum current that is slowly ramped up and down by a bypass current digital-to-analog converter (DAC). A digital value to the bypass current DAC is ramped up or down before an LED current is turned on or off. When the LED current is turned on, current is shifted from a bypass path to a path through the LED, maintaining a constant sum current from the DC-DC converter. When a different LED is turned on, current is shifted from one LED's path to the other LED's path. Separate LED current DAC's in each LED path and in the bypass path can share the sum current with digital precision. Using a single DAC for the sum current and switches in each path reduces cost.
    Type: Grant
    Filed: August 25, 2011
    Date of Patent: November 12, 2013
    Assignee: Hong Kong Applied Science & Technology Research Institute Co., Ltd.
    Inventors: Kwok Kuen (David) Kwong, Lee L. Yang, Yunlong Li, Weina Zhou
  • Current-Switching LED Driver Using DAC to Ramp Bypass Currents to Accelerate Switching Speed and Reduce Ripple
    Publication number: 20130049628
    Abstract: A light-emitting diode (LED) driver provides faster rise and fall times for LED current to reduce image sticking and other interference. A standard DC-DC converter provides a sum current that is slowly ramped up and down by a bypass current digital-to-analog converter (DAC). A digital value to the bypass current DAC is ramped up or down before an LED current is turned on or off. When the LED current is turned on, current is shifted from a bypass path to a path through the LED, maintaining a constant sum current from the DC-DC converter. When a different LED is turned on, current is shifted from one LED's path to the other LED's path. Separate LED current DAC's in each LED path and in the bypass path can share the sum current with digital precision. Using a single DAC for the sum current and switches in each path reduces cost.
    Type: Application
    Filed: August 25, 2011
    Publication date: February 28, 2013
    Applicant: Hong Kong Applied Science & Technology Research Institute Compnay Limited
    Inventors: Kwok Kuen (David) KWONG, Lee L. YANG, Yunlong LI, Weina ZHOU