Automatic amplitude control type crystal oscillator

Abstract

The invention relates to an automatic amplitude control type crystal oscillator, which comprises a current mirror circuit controlled by amplitude, an inverter, a first pulse switch, a second pulse switch and a bias resistor; the first pulse switch is connected to the source of a mirror image tube in the current mirror circuit, and the second pulse switch is connected to the grounding end of the inverter; by setting the control pulse of the first pulse switch, the first pulse switch is closed when the sine wave output by the phase inverter is at the peak value, the phase inverter charges the crystal in a short time, and the energy injection efficiency is improved; and the control pulse of the first pulse switch and the control pulse of the second pulse switch are opposite in phase and are not overlapped, so that a PMOS tube and an NMOS tube of the phase inverter do not work simultaneously; therefore, the short-circuit power consumption of the phase inverter is eliminated, and the overall power consumption of the crystal oscillator is reduced.

Description

technical field [0001] The invention relates to the technical field of crystal oscillators, in particular to an automatic amplitude control type crystal oscillator. Background technique [0002] In IoT applications, ultra-low power consumption systems such as wireless sensory nodes stay in a dormant state for a long time and wake up to work through the real-time clock (RTC) to extend the service life of the device. When the system is in sleep mode, RTC consumes the main power consumption of the entire system, so an ultra-low power oscillator is required as the clock source of RTC. Common oscillators are mainly divided into two types, one is RC oscillator, the power consumption can reach sub-nW level, but the accuracy is relatively low, for systems that need to send and receive data each other, such as between wireless sensing nodes and nodes , the low precision of the clock will cause a time error between the two clock references, resulting in a huge waste of wake-up power ...

AI Technical Summary

Problems solved by technology

[0003] In order to reduce the power consumption of the crystal oscillator, an automatic amplitude control crystal oscillator was proposed. The traditional automatic amplitude control crystal oscillator controls the charging current of the crystal through amplitude feedback, so that the crystal maintains low-amplitude oscillation and reduces power consumption, but through a The amplitude-controlled current mirror provides bias current for the inverting amplifier. The current mirror itself consumes high power consumption and is in the state of charging the crystal for a long time. In fact, the crystal only needs a small part of energy to maintain oscillation, and the rest is equal to is consumed, which greatly reduces the crystal energy injection efficiency

And because the input terminal of the inverting amplifier is a sine wave, the PMOS and NMOS of the inverter will be turned on at the same time, resulting in a large short-circuit power consumption

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