Patents by Inventor David Philip Martin Chown

David Philip Martin Chown 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).

  • Driver circuit for a solid state optical emitter device
    Patent number: 6028871
    Abstract: The present invention relates to a circuit for driving a solid state optical emitter device such as a laser diode, and in particular a circuit which limits the maximum current which may be drawn through the device. The circuit comprises a current supply path and a current return path to which the optical emitter may be connected, and a current limit device to limit a maximum current that may flow through one of the current paths. The current limit device has a current mirror with an input portion and an output portion, the circuit being arranged so that when a first current flows through the input portion, the second portion is predisposed to supply a second current up to a maximum which mirrors the first current. The maximum current through the paths is thereby limited in accordance with the maximum of the second current.
    Type: Grant
    Filed: October 23, 1998
    Date of Patent: February 22, 2000
    Assignee: Hewlett-Packard Company
    Inventors: John Barry Vaughan, David Philip Martin Chown, David Martin Gee