Patents Assigned to Unitrode Corp.
  • Patent number: 4849656
    Abstract: A threshold comparator having hysteresis wherein the repeatable threshold levels are established by multiple current paths and resistance ratios, which provides an under-voltage lock-out signal. The current paths are established by transistors fabricated on a common substrate and include a split collector P-N-P transistor that provides the distribution of the input signal to the various current paths. The turn-on and turn-off threshold points of the circuit according to the present invention are established by resistance ratios which are more easily maintained than are absolute resistance values. Similarly, when implemented on a common substrate, the remaining component values may be selected so that the thresholds values are nearly independent of temperature, providing an easily manufactured, high yield circuit.
    Type: Grant
    Filed: June 11, 1987
    Date of Patent: July 18, 1989
    Assignee: Unitrode Corp.
    Inventor: Robert A. Neidorff