A crystal oscillator circuit

Abstract

The invention relates to a crystal oscillating circuit, which comprises an oscillating stage circuit, a direct current negative feedback circuit, and a push-pull amplifier circuit. The oscillating stage circuit generates an oscillator signal and outputs the oscillator signal to the direct current negative feedback circuit; the direct current negative feedback circuit performs amplitude control on the oscillator signal of the oscillating stage circuit and feeds back the oscillator signal to the oscillating stage circuit; the oscillating stage circuit outputs the oscillator signal which is subjected to the amplitude control to the push-pull amplifier circuit by the direct current negative feedback circuit; and the push-pull amplifier circuit is a post-stage amplifying circuit, amplifies the oscillator signal which is input and subjected to the amplitude control and outputs the oscillator signal to the outside. According to the invention, a transistor V5 adopts an emitter follower, so that an output load of the crystal oscillating circuit is less, and oscillation starting of the crystal is facilitated; and the capacitance of a capacitor which is connected in series with the crystal is increased, so that the capacitive reactance of the capacitor in the circuit is reduced, an alternating current which runs through the crystal is increased, and the driving power of the crystal is increased.

Description

technical field [0001] The invention relates to a crystal oscillation circuit. Background technique [0002] Crystal oscillation circuit is an important part of various electronic equipment circuits. The design of its crystal excitation power has a great influence on the reliability of the equipment. Since the selection of crystal excitation power involves many parameters, the selection of different parameters has great influence on the existing If the crystal oscillator circuit is not properly designed, the crystal excitation power will be insufficient or too large, which cannot meet the conditions for the crystal to start oscillating, so that the crystal will not oscillate or stop oscillating intermittently. [0003] The existing capacitive three-point crystal oscillator circuit has the following deficiencies in design: [0004] (1) The capacitance value connected in series with the crystal is too small, resulting in insufficient excitation power of the crystal, so that t...

AI Technical Summary

Problems solved by technology

[0004] (1) The capacitance value connected in series with the crystal is too small, resulting in insufficient excitation power of the crystal, so that the crystal does not vibrate or stops vibrating intermittently after starting to vibrate;

[0005] (2) The output load of the crystal oscillator circuit is relatively large, and the load capacity is not strong

[0006] (3) The DC voltage at the base of the triode will affect the stability of the crystal oscillator circuit

[0007] (4) The waveform of the crystal oscillator circuit is poor, and the selection of the static operating point of the crystal oscillator circuit is not appropriate

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