RING OSCILLATING CIRCUIT, DELAYED TIME MEASURING CIRCUIT, TEST CIRCUIT, CLOCK SIGNAL GENERATING CIRCUIT, IMAGE SENSOR, PULSE GENERATING CIRCUIT, SEMICONDUCTOR INTEGRATED CIRCUIT AND ITS TESTING METHOD

摘要

A ring oscillating circuit is provided to perform a stably continuous ring oscillating operation by positive feedback and its highly precise timing measurement is applied to accurate measurement of delayed time, jitters in a clock signal, or the like. A ring oscillating circuit (1) is composed of a delay circuit (2) and a one-shot multivibrator (3). An output of the delay circuit (1) is connected to an input of the one-shot multivibrator (3) and an output of the one-shot multivibrator (3) is connected to an input of the delay circuit (1), so that the delay circuit (2) and the one-shot multivibrator (3) form a positive feedback loop. A oscillation starting-up circuit (4) which accepts an trigger pulse input for starting-up oscillation and starts up the oscillation is provided on the positive feedback loop or in the inside of the delay circuit (2) and the one-shot multivibrator (3).