Threshold voltage degradation measuring circuit

The invention relates to the technical field of integrated circuits and provides a threshold voltage degradation measuring circuit. The circuit comprises two MOS (Metal Oxide Semiconductor) tubes which are connected in series, wherein the first MOS tube is a detected tube; a grid electrode of the first MOS tube is connected with first direct-current voltage, a source electrode and a substrate of the first MOS tube are simultaneously connected with source electrode voltage, and a drain electrode of the first MOS tube is connected with an output end; a grid electrode and a drain electrode of the second MOS tube are simultaneously connected with second direct-current voltage, and a source electrode and a substrate of the second MOS tube are simultaneously connected with the output end. According to the scheme disclosed by the invention, the threshold voltage degradation measuring circuit with a simple structure is provided; the circuit only comprises the two MOS tubes which are connected in series and the threshold voltage degradation condition of the tube to be detected can be directly measured by only measuring the voltage change of the output end; and the circuit only relates to the obtaining of one physical amount and does not need to carry out secondary process and analysis, so that the technical scheme has the advantages of simple structure, convenience for operation, time-saving property, accurate and direct results and easiness in implementation.