Oscillator

Abstract

The oscillator comprises a biasing circuit, a first charging and discharging circuit, a second charging and discharging circuit, an oscillation control circuit, a reference resistor, a first feedback control circuit and a second feedback control circuit. The bias circuit is used for generating bias current. The first charging and discharging circuit and the second charging and discharging circuit charge and discharge the first capacitor and the second capacitor alternately under the control of the oscillation control circuit. Under the control of a first pulse signal from the first pulse generator, the first feedback control circuit controls the resistance value of the first resistor according to the result of comparing the charging peak voltage of the first capacitor with the reference voltage. And under the control of a second pulse signal from the second pulse generator, the second feedback control circuit controls the resistance value of the second resistor according to a comparison result of the charging peak voltage of the second capacitor and the reference voltage. By controlling the charging time of the capacitor, a small change is generated in a plurality of continuous charging and discharging periods, and long-term jitter is reduced.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuits, in particular to an oscillator. Background technique [0002] At present, RC oscillators are widely used. In some applications, the precision of the oscillator is very high. For example, when the Bluetooth communication system works in breathing mode, a 32KHz low-frequency clock is required, and the timing is 500 milliseconds to intermittently wake up the system for communication. shake hands. The system wakes up every 500 milliseconds, works for 5 milliseconds, looks for a paired device, and continues to sleep if not found. The 32KHz low-frequency clock usually uses long-term jitter to evaluate the accuracy of the clock. If this index is too large, the system needs to be designed to wake up earlier than the deviation timing, resulting in extra power consumption. Therefore, the more accurate the long-term jitter design is, the better. Some vibrators in the prior art can achieve...

AI Technical Summary

Problems solved by technology

The 32KHz low-frequency clock usually uses long-term jitter to evaluate the accuracy of the clock. If this index is too large, the system needs to be designed to wake up in advance of the timing time of its deviation, which will consume additional power consumption

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