Ring oscillation circuit, delay time measuring circuit, testing circuit, clock generating circuit, image sensor, pulse generating circuit, semiconductor integrated circuit, and testing method thereof

摘要

A ring oscillation circuit, which can operate the ring oscillation due to a positive feedback stably and continuously, is provided and it is applied to an accurate measurement of delay time and a measurement of timing accuracy in a jitter of a clock signal or the like with a high accuracy. A ring oscillation circuit comprises a delay circuit and a monostable multivibrator. An output of the delay circuit is connected to an input of the monostable multivibrator, an output of the monostable multivibrator is connected to an input of the delay circuit, and the delay circuit and the monostable multivibrator configure a positive feedback loop. An oscillation starting circuit for starting oscillation upon receipt of an input of a trigger pulse for triggering oscillation is provided on the positive feedback loop, or in the inside of the delay circuit or the monostable multivibrator.