Patents by Inventor Othmar Pfarrkircher

Othmar Pfarrkircher 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: 6278390
    Abstract: A circuit arrangement for monitoring an output load (4) of a digital-to-analog current converter (1). The digital-to-analog converter supplies an analog output current dependent on a digital comparison data word to a first resistor (2) and, if present, to the output load (4) arranged in parallel with the first resistor. In order to provide a continuous monitoring of the output load, a digital first comparator (12) compares the data words applied to the digital-to-analog current converter (1) with at least one comparison data word. An analog second comparator (5) compares the voltage drop across the first resistor with at least one reference voltage and applies its output signal to a flip-flop (8). A comparison circuit (11) monitors the magnitude and/or the presence of the output load dependent on the output signals of the first comparator and the flip-flop.
    Type: Grant
    Filed: March 4, 1999
    Date of Patent: August 21, 2001
    Assignee: U.S. Philips Corporation
    Inventors: Robert Meyer, Othmar Pfarrkircher
  • Patent number: 6154160
    Abstract: A circuit checks the value and the existence of an external load of a digital-to-analog current converter. A first comparator compares a digital word to be converted, with a comparison data word. The output signal of the first converter indicates during which periods the digital data word is greater and during which periods it is smaller than the comparison data word. A second comparator compares the voltage at the output of the converter with a reference voltage. The output signal of the second converter indicates during which periods the output voltage is greater and during which periods it is smaller than the reference voltage. A comparison circuit checks the existence and the value of the output load by comparing the time periods indicated by the output signals of the two converters. Thus, a conclusion about the existence and the value of the output load is possible at any time.
    Type: Grant
    Filed: February 19, 1999
    Date of Patent: November 28, 2000
    Assignee: U.S. Philips Corporation
    Inventors: Robert Meyer, Othmar Pfarrkircher