Patents by Inventor Chit Sang Chan

Chit Sang Chan 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: 11942942
    Abstract: A level shifter circuit uses standard n-channel and p-channel transistors except for a pair of Lateral-Diffusion Metal-Oxide-Semiconductor (LDMOS) transistors that have an added lateral diffusion under the gate between the source and the conduction channel, increasing the breakdown voltage. The source of each LDMOS transistor connects to a drain of a transient differential transistor that has its gate driven by a oneshot that generates a pulse after an input transition. After the pulse ends a holding differential transistor draws a smaller bias current from the LDMOS transistors. The source of each LDMOS transistor connects to the drain and gate of a p-channel sensing transistor that drives gates of mirror transistors generating mirrored currents to cross-coupled n-channel mirror transistors that drive both terminals of a bistable latch that holds the output using a floating ground between driver transistors of a Buck converter switched by the bistable latch.
    Type: Grant
    Filed: November 21, 2022
    Date of Patent: March 26, 2024
    Assignee: Hong Kong Applied Science and Technology Research Institute Company Limited
    Inventors: Chit Sang Chan, Wei Qian, Ziyang Gao
  • Patent number: 11646737
    Abstract: A level-shifting output buffer has cascode transistors with varying rather than fixed gate bias voltages. An adaptive regulator bypasses the I/O pad voltage to a regulator output when the I/O begins switching, but later clamps the regulator output to a middle bias voltage. The regulator output can be applied to a supply terminal of a buffer that drives the gate of the cascode transistor. Since the adaptive regulator follows the I/O pad voltage as switching begins, a voltage boost is provided to the gates of the cascode transistors, allowing for higher currents or smaller cascode transistors and preventing over-voltage stress. The adaptive regulator has an n-channel bypass transistor between the I/O pad and the regulator output, and an n-channel clamp transistor between the regulator output and the middle bias, with a gate driven from the I/O pad by either a p-channel gate-biasing transistor or an n-channel gate-biasing transistor.
    Type: Grant
    Filed: July 29, 2022
    Date of Patent: May 9, 2023
    Assignee: Hong Kong Applied Science and Technology Research Institute Company Limited
    Inventors: Chit Sang Chan, Chun-Kit Yam
  • Patent number: 7239117
    Abstract: A DC-DC converter circuit includes an inductor having an inductor current, an inductor current emulation circuit for producing an emulated inductor current, and a control circuit coupled with the emulation circuit for receiving the emulated inductor current and determining a peak inductor current for the DC-DC converter.
    Type: Grant
    Filed: January 6, 2005
    Date of Patent: July 3, 2007
    Assignee: Solomon Systech Limited
    Inventors: Cheung Fai Lee, Stephen Wai-Yan Lai, Alvin Chit-Sang Chan, David Chin-Tung Or