Patents Examined by Peter S. Wrong
  • Patent number: 6172495
    Abstract: A method and apparatus for mirroring currents in application specific integrated circuits provides higher current mirroring accuracy than previously obtainable with matched active devices by using small groups of resistors with local matching to create a summing node which represents the average voltage across the source resistors of the active output devices and by forming a reference resistor through the combination of resistors from the local resistor groups such that the reference resistor has properties which will largely cause cancellation of location gradients and initial value variation in the resistor groups. An error amplifier compares the voltage at the summing junction with the voltage across the reference resistor and adjusts its output voltage to drive the paralleled gates of each active mirror output device such that the summing junction and reference resistor voltages remain equal.
    Type: Grant
    Filed: February 3, 2000
    Date of Patent: January 9, 2001
    Assignee: LSI Logic Corporation
    Inventor: Clyde Washburn