Automatic clock oscillator calibration method and circuit

Abstract

The invention discloses an automatic clock oscillator calibration method and an automatic clock oscillator calibration circuit adopted for implementation of the method. The automatic clock oscillator calibration method comprises the following steps of: generating a specific period T through counting of an external precision reference clock, counting clock signals to be calibrated during the period T, comparing an obtained count value with a standard count value of the clock signals to be calibrated, carrying out rough adjustment by increasing or decreasing a control word with dichotomy according to the comparison results, realizing that a frequency of the clock signals output by a clock oscillator to be calibrated is within the acceptable error limit of a frequency corresponding to the standard value, then carrying out fine adjustment around a control word which is obtained by rough adjustment and finding a control word which can minimize the frequency error. The invention can be used for rapidly calibrating the clock oscillator, thereby greatly improving calibration speed of the clock oscillator and guaranteeing precision of the calibration.

Description

technical field [0001] The invention relates to a method for automatically calibrating a clock oscillator. The invention also relates to a circuit related to a clock oscillator, in particular to a clock oscillator automatic calibration circuit. Background technique [0002] Due to the error of the manufacturing process of the clock oscillator, dies in different places of the same wafer will produce different oscillation frequencies, so the frequency of the clock signal of the clock oscillator needs to be calibrated before using the clock oscillator. In the existing clock oscillator, a control word is set in the oscillator to adjust the current or voltage inside the oscillator to adjust the frequency of the oscillator. The control word is stored in the circuit in digital form. When controlling the clock frequency, it will control Words are converted into corresponding analog quantities to control the clock signal frequency of the clock oscillator. The size of the control wo...

AI Technical Summary

Problems solved by technology

At present, when the frequency of the clock signal of the clock oscillator is calibrated, the setting of the control word is often done manually, which is very inefficient.

Images