Design of an externally adjustable oscillator circuit

Abstract

In view of the traditional RC oscillator's low accuracy and inability to be adjusted, a new repairable and adjustable high-precision RC oscillator is proposed. The oscillator is composed of two inverters, comparators, controllable switches, capacitors and resistors. The comparator generates output voltage by comparing the capacitor voltage value and the reference voltage value. At the same time, it controls the working state of the switching MOS tube to complete the cyclic charge and discharge of the capacitor. The two groups of capacitors charge and discharge alternately, and then produce continuous oscillation waveform. The high-frequency clock is realized by alternating comparison between bilateral comparator and bias voltage. The advantage of this mode is that the oscillation frequency is only related to the charging time, but has nothing to do with the discharge time. There is no need to consider the influence of the discharge time delay on the frequency. In this paper, the coarse adjustment of the accuracy of the oscillator is realized by adjusting the charging current of the capacitor, and then the output of the oscillator is accurately adjusted by selecting the capacitance value of the capacitor.