Patent ID: 6618279
Filing Date: 2003-09-09
Classification: G11C

Abstract:
A method for determining a desired operating impedance for an operating circuit, the operating circuit having a plurality of discrete, selectively adjustable impedance values associated therewith, the method comprising:applying, to a reference circuit, a test impedance value, said test impedance value controlled by a binary count; determining, based upon said applied test impedance value, whether said reference circuit is in either a first state or a second state; incrementing said binary count if said reference circuit is in said first state and decrementing said binary count if said reference circuit is in said second state, thereby increasing said applied test impedance value if said binary count is incremented and decreasing said applied test impedance value if said binary count is decremented; determining a condition in which said reference circuit oscillates between said first state and said second state; storing a pair of binary count values, one of said pair of binary count values representing a first impedance value which causes said reference circuit to change from said first state to said second state, the other of said pair of binary count values representing a second impedance value which causes said reference circuit to change from said first state to said second state; and adjusting the lower of said stored pair of binary count values so as to create a buffered count by subtracting a predetermined, fixed value therefrom; wherein the desired operating impedance for the operating circuit corresponds to said buffered count.