Patents by Inventor Torbjorn Ivar Randahl

Torbjorn Ivar Randahl 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).

  • xDSL-line-interface-circuit
    Patent number: 7801296
    Abstract: at least one self oscillating loop circuit which oscillates with a switching frequency (fs), wherein the self oscillating loop circuit (18, 19, 20) comprises an output driver (19) which is switched with said switching frequency and a loop filter (20) which feeds back an amplified loop signal output by said driver (19) to an input of said self oscillating loop and a trimming circuit (21) for trimming the switching frequency (fs) of said self oscillating loop circuit.
    Type: Grant
    Filed: January 27, 2005
    Date of Patent: September 21, 2010
    Assignee: Infineon Technologies AG
    Inventors: Karl Stefan Barkarö, Bo Bokinge, Jörg Hauptmann, Karl-Mikael Johanson, Lars Karlsson, Torbjörn Ivar Randahl
  • Class D-amplifier
    Patent number: 7282992
    Abstract: A class D-amplifier which amplifies an input signal applied to an signal input of said amplifier (21) to generate an amplified signal output by an signal output (28a, 28b) of said amplifier comprising a comparator (23) which compares the applied input signal with a switch signal to generate a pulse width modulated signal; a driving unit (24) which amplifies the pulse width modulated signal to generate the amplified output signal; and a feedback circuit which generates the self oscillating switch signal for the comparator (23).
    Type: Grant
    Filed: June 15, 2005
    Date of Patent: October 16, 2007
    Assignee: Infineon Technologies AG
    Inventors: Karl Stefan Barkaro, Bo Bokinge, Carl-Mikael Johansson, Lars Karlsson, Torbjorn Ivar Randahl, Andreas Wiesbauer
  • Method for off-hook detection during ringing and the use of a subscriber line interface circuit for off-hook detection during ringing
    Patent number: 5734712
    Abstract: A method and an apparatus for off-hook detection in a subscriber line interface circuit responds to a ringing signal which preferably lacks a DC component. A signal is generated that is a function of the line current through the subscriber line, and the time at which the signal exceeds a predetermined current value is measured. The measured time is compared with a predetermined time value, and an off-hook indication is produced in a processor depending on the comparison.
    Type: Grant
    Filed: January 20, 1995
    Date of Patent: March 31, 1998
    Assignee: Telefonaktiebolaget LM Ericsson
    Inventor: Torbjorn Ivar Randahl