| 摘要 |
<p>PURPOSE:To obtain a stable crystal oscillation without generating a self- oscillation by making a first inverter to amplify the output of a crystal oscillating circuit into the inverter of a Schmitt trigger input in a crystal oscillator having plural inverter stages in the internal part of a CMOS structure. CONSTITUTION:When the output of a crystal oscillator is changed from an L level to an H level or from the H level to the L level, a current instantaneously flows between power sources, a noise occurs and the noise of 12 or 14 is fed back to an input 9 of a crystal oscillating circuit through a power source line. It is amplified by an oscillation inverter 1, and the waveform of 13 and 15 is outputted to the output of the crystal oscillating circuit. The waveform is inputted to the inverter 7 of Schmitt a trigger input, and for an inverter 7, when a voltage to exceed a high level threshold VP or a voltage to lower a low level threshold VN is not inputted, the output is not inverted. For this reason, since the voltage does not arrive at the threshold at waveforms 13 and 15, the inverter 7 does not respond. Consequently, a feedback loop is stopped and the self-oscillation cannot be executed.</p> |
