Patents by Inventor Berthold Birk

Berthold Birk 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).

  • Circuitry for dimming a fluorescent lamp
    Patent number: 6351080
    Abstract: In a circuit arrangement for the dimmable operation of a fluorescent lamp at the operating frequency (f1), having an apparatus for switching the operating frequency (f1) on and off at a dimming frequency (f2), the pulse width (W2) of the dimming frequency (f2) being variable, and where f2<f1, it is provided that the fluorescent lamp current is simultaneously adjustable by the apparatus by the supply voltage being switched on and off at a switching frequency (f3) with a variable pulse width (W3), where f3>f1.
    Type: Grant
    Filed: January 19, 2000
    Date of Patent: February 26, 2002
    Assignee: Mannesmann VDO AG
    Inventors: Berthold Birk, Günter Hahlganss, Walter Kares, Ulrich Roskoni
  • Method for dimming a fluorescent lamp arranged in the secondary circuit of a transformer and arrangement to implement said method
    Patent number: 6313585
    Abstract: A method for dimming a fluorescent lamp, in which a transformer is driven by an AC voltage in a push-pull manner. In a method which ensures flicker-free light emission over a wide temperature range at the highest possible dimming rate, a resonant circuit containing the current transformer, the secondary capacitance element and the fluorescent lamp is momentarily made to oscillate in an ionization phase in such a way that the fluorescent lamp is reliably prevented from illuminating, and then the fluorescent lamp is positively controlled.
    Type: Grant
    Filed: January 14, 2000
    Date of Patent: November 6, 2001
    Assignee: Mannesmann VDO AG
    Inventor: Berthold Birk