Patent ID: 6897662

Claim:
An apparatus for determining a state of a measurable circuit element having a plurality of states and a different impedance in each state, comprising: a replicate circuit having a replicate circuit element and configured to generate a first test current through the replicate circuit element, the replicate circuit element having similar electrical characteristics as the measurable circuit element; and a trim determination circuit coupled with the replicate circuit, the trim determination circuit including the measurable circuit element and configured to generate a second test current dependent on the first test current through the measurable circuit element the trim determination circuit further including a scaled reference current source for generating a scaled reference current and a dependent measurable current source coupled with the scaled reference current source for generating a measured current whereby the amount of the measured current is a function of a first voltage drop across the measurable circuit element and the state of the measurable circuit element is determined by the difference between the scaled reference current and the measured current.