Patents by Inventor WAI-KEUNG CHENG

WAI-KEUNG CHENG 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: 9468055
    Abstract: Parallel light emitting diode channels may be controlled using a pulsed control signal input characterized by an input duty cycle and one or more current sense input signals. Each of the one or more current sense input signals is indicative of a current through a corresponding load channel of one or more load channels. One or more pulsed channel current control signals are provided to one or more corresponding dimming controls correspondingly coupled to the one or more load channels. Each of the dimming controls is configured to provide an output signal to a corresponding ON-OFF switch, each of which is coupled in series with a corresponding the load channels. The channel duty cycle of each channel current control signal is adjusted relative to the input duty cycle in response to the current sense input signals.
    Type: Grant
    Filed: October 24, 2011
    Date of Patent: October 11, 2016
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INCORPORATED
    Inventors: Wai-Keung Cheng, Son Tran
  • Publication number: 20130099684
    Abstract: Parallel light emitting diode channels may be controlled using a pulsed control signal input characterized by an input duty cycle and one or more current sense input signals. Each of the one or more current sense input signals is indicative of a current through a corresponding load channel of one or more load channels. One or more pulsed channel current control signals are provided to one or more corresponding dimming controls correspondingly coupled to the one or more load channels. Each of the dimming controls is configured to provide an output signal to a corresponding ON-OFF switch, each of which is coupled in series with a corresponding the load channels. The channel duty cycle of each channel current control signal is adjusted relative to the input duty cycle in response to the current sense input signals.
    Type: Application
    Filed: October 24, 2011
    Publication date: April 25, 2013
    Applicant: Alpha and Omega Semiconductor Incorporated
    Inventors: WAI-KEUNG CHENG, Son Tran