| 摘要 |
PROBLEM TO BE SOLVED: To obtain a method of measuring capacity value by which the capacity value of an object to be measured can be measured accurately even when a leakage current of a nonnegligible level occurs in the capacity of the object. SOLUTION: In this method, a test current ICnorm is measured by using a normal PMOS gate potential Gp1 as a PMOS gate potential Gp which performs on/off control on PMOS transistors MP1 and MP2 in a prescribed period in a first step S1. In a second step S2, a current ICrat is measured by using an on-period geometric multiple PMOS gate potential Gp2, the "L" period and trailing time of which are geometric multiples of the normal PMOS gate potential Gp1. In a step S3, the current value of a capacity current CIC composed only of a capacity current ICt component is calculated by eliminating the leakage current IRt, based on current ICnorm and current ICrat. Thereafter, a target capacity CCt is found based on the capacity current CIC and a charging frequency found in a step 4 in a step 5. COPYRIGHT: (C)2004,JPO
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