Patents by Inventor Franciscus H. T. Lammers

Franciscus H. T. Lammers 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: 5909089
    Abstract: The invention relates to a circuit arrangement for igniting and operating a high-pressure discharge lamp provided with a control circuit which limits the voltage to a value Vb across the output terminals of the circuit arrangement such that:Vla<Vb<Vi.wherein Vla is the nominal lamp voltage and Vi is the threshold voltage across the output terminals at which the ignitor starts.
    Type: Grant
    Filed: April 16, 1997
    Date of Patent: June 1, 1999
    Assignee: U.S. Philips Corporation
    Inventors: Oscar J. Deurloo, Franciscus H. T. Lammers
  • Patent number: 5532528
    Abstract: A circuit arrangement which is provided with an up-converter (3) which comprises at least an inductive device (31), a switch (32), and a capacitive device (34) which in the operational state is periodically charged with a charging current in dependence on periodic switching of the switch. The switch is switched to the conducting state periodically during a substantially constant time t.sub.on. The circuit arrangement is provided with detection circuitry (I) for direct detection of the charging current. As a result, a load current which has a sinusoidal shape by good approximation is drawn from a connected AC voltage supply source by the circuit arrangement.
    Type: Grant
    Filed: May 17, 1995
    Date of Patent: July 2, 1996
    Assignee: U.S. Philips Corporation
    Inventor: Franciscus H. T. Lammers
  • Patent number: 4935672
    Abstract: A DC-AC converter for igniting and supplying a gas discharge lamp (1). The converter has two input terminals (C, D) to be connected to a DC voltage source. The input terminals are interconnected by means of a series arrangement that includes a load circuit comprising at least the lamp (1) and an induction coil (5), and a first semiconductor switching element (6) including a freewheel diode. The load circuit is bridged by a circuit including a second semiconductor switching element (7) with a freewheel diode. The semiconductor switching elements (6, 7) are provided with control circuits for rendering said switching elements alternately conducting. The control circuit (9) of switching element (7) has a voltage measuring point which is connected via a rectifier element (10) to the control circuit (8) of the first switching element.
    Type: Grant
    Filed: June 2, 1988
    Date of Patent: June 19, 1990
    Assignee: U.S. Philips Corporation
    Inventors: Franciscus H. T. Lammers, Henk Houkes, Paul R. Veldman