Patents by Inventor Chunhe Zhao

Chunhe Zhao 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).

  • High isolation switch
    Patent number: 8575989
    Abstract: A switch is provided. The circuit includes a plurality of transistors configured to electrically isolate the input of the switch from the output of the switch. In one embodiment, for example, the plurality of transistors may be configured to provide at least one path between the input and the output of the switch, and to provide at least three layers of electrical isolation between the input and the output of the switch when the switch is open.
    Type: Grant
    Filed: July 10, 2012
    Date of Patent: November 5, 2013
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Douglas A. Garrity, Chunhe Zhao
  • Controlled bias current buffer and method thereof
    Patent number: 6707339
    Abstract: An operational amplifier circuit (10) uses a first operational amplifier (16) to selectively provide a boosted drive current in response to an input signal voltage transitioning. The boosted driver current is used by a second operational amplifier (22) having a single high gain stage (76). The output drive current of the operational amplifier circuit (10) is increased to a predetermined maximum value for a predetermined time after an input signal transition in order to source increased current to a capacitive or inductive load only during output signal transitions. Separate current boost circuits (30, 70) in each of the first and second operational amplifiers enable early signal transition detection and ensure continuation of increased current until completion of the signal transition.
    Type: Grant
    Filed: November 22, 2002
    Date of Patent: March 16, 2004
    Assignee: Motorola, Inc.
    Inventors: Kiyoshi Kase, Joseph Y. Chan, Chunhe Zhao