METHOD AND APPARATUS OF DETERMINING RATIO BETWEEN TIME CONSTANT IN INTEGRATED CIRCUIT AND DESIRED VALUE FOR REDUCING COMPLEXITY OF INTEGRATED CIRCUIT BY ENSURING EXACT DETERMINATION FOR RATIO OF RC TIME CONSTANT OF AT LEAST ONE RC ELEMENT WITHIN SMALL SURFACE AREA ON INTEGRATED CIRCUIT

摘要

PURPOSE: A method and an apparatus of determining a ratio between a time constant in an integrated circuit and a desired value are provided to reduce the complexity of the integrated circuit by ensuring the exact determination for the ratio of an RC time constant of at least one RC element within a small surface area on the integrated circuit. CONSTITUTION: A first reference RC element having a first resistor(R1) and a first capacitor(C1), and a second RC element having a second resistor(R2) and a second capacitor(C2) are provided. A normalized RC time constant for the two reference RC elements(R1,C1,R2,C2) is defined. Successive charge and discharge cycles are implemented during a predetermined evaluation period. The evaluation period is matched to the normalized RC time constant. The number of charge and discharge cycles actually implemented is determined. A value corresponding to a quotient of the actual number and the predetermined number are provided in order to provide a measure of the ratio of the normalized RC time constant to the RC time constant of the reference RC elements.