Patents Assigned to NorthStar Technologies Inc.
  • Patent number: 6300758
    Abstract: A magnetoresistive sensor for use in detecting relative motion between the sensor and a further object bearing an alternating pattern of north/south magnetic poles. The sensor includes one or more pairs of magnetoresistive elements positioned so that each element within a pair magnetically complements the corresponding element in that pair. That is, whenever an element is exposed to a north pole of the magnetic pattern, a corresponding complementary element is exposed to a south pole so as to provide a magnetically complemented output. Such pair of complementary magnetoresistive elements are connected into a bridge circuit such that jitter effects caused by asymmetric magnetic fields and physical differences between sensor elements are cancelled. The quadrature sensor output is frequency multiplied to provide frequency multiplied output signals in quadrature.
    Type: Grant
    Filed: December 2, 1999
    Date of Patent: October 9, 2001
    Assignee: NorthStar Technologies Inc.
    Inventors: Neil C. Griffen, Richard S. Stokes
  • Patent number: 6246233
    Abstract: A magnetoresistive sensor for use in a rotary encoder with a drum having a circumference covered with a magnetic track at a predetermined pitch includes a plurality of magnetoresistive elements positioned opposite the drum and connected in a bridge circuit such that when the drum rotates an output signal from the bridge indicates a rotary angle of the drum. The magnetoresistive elements include one or more complementary pairs of elements positioned 180° out of phase. Each of such pair of complementary magnetoresistive elements is connected in one leg of a bridge circuit such that jitter effects caused by asymmetric magnetic fields and physical differences between sensor elements are cancelled. Magnetoresistive sensor element configurations for minimizing the impact of temperature gradients across the magnetoresistive sensor are also disclosed.
    Type: Grant
    Filed: May 27, 1997
    Date of Patent: June 12, 2001
    Assignee: NorthStar Technologies Inc.
    Inventors: Neil C. Griffen, Richard S. Stokes