High-precision digitally controlled oscillator for high-frequency all-digital phase-locked loop

Abstract

The invention relates to a high-precision numerically controlled oscillator for a high-frequency all-digital phase locked loop. The high-precision numerically controlled oscillator comprises an inductor, a capacitor array and a differential coupling pair tube, wherein the capacitor array comprises a coarse tuning capacitor array and a fine tuning capacitor array, the fine tuning capacitor array comprises a plurality of high-precision capacitor units, each high-precision capacitor unit comprises three MOM capacitors and two NMOS tubes, the third MOM capacitor is respectively connected with one end of the first MOM capacitor and one end of the second MOM capacitor, the other ends of the first MOM capacitor and the second MOM capacitor are respectively connected with a differential clock output, drain electrodes of the two NMOS tubes are respectively connected to both ends of the third MOM capacitor, grid electrodes of the two NMOS tubes are in a short circuit and are connected with a control word, and source electrodes of the two NMOS tubes are in the short circuit and are grounded. The high-precision numerically controlled oscillator provided by the invention can meet the design requirements of a minimum effective capacitance value change which is smaller than the minimum capacitance in a process database, and thus the high-precision numerically controlled oscillator has obvious advantages compared with the traditional numerically controlled oscillator.

Description

technical field [0001] The invention belongs to the technical field of high-speed data communication integrated circuits. The invented new high-precision digital control oscillator can be applied to various digital phase-locked loop systems. The high-precision digital control oscillator can improve the accuracy of the oscillator capacitance, thereby reducing The minimum gain of the small digitally controlled oscillator suppresses phase noise and reduces clock jitter. Background technique [0002] figure 1 It is a typical all-digital phase-locked loop system, which is mainly composed of frequency and phase detector 101 , digital loop filter 102 , LC type digitally controlled oscillator 103 and frequency divider 104 . The reference clock 105 and the output signal 109 of the frequency divider 104 are processed by the frequency and phase detector 101 to obtain the phase lead / lag signal 106, and the signal is processed by the digital loop filter 102 to obtain the control word 10...

AI Technical Summary

Problems solved by technology

The problem faced by the first solution is that the capacitor built by the designer is easily affected by the process deviation and does not match the design index, and it is difficult to control the specific capacitance value; although the second solution seems to solve the problem of the minimum capacitance value, it is achieved by using simulation. The phase-locked loop voltage-controlled oscillator solution is solved, and the final result is a digital / voltage hybrid control oscillator structure, which will face the linearity problem of the oscillator gain faced by the voltage-controlled oscillator, while the pure digital control The oscillator has excellent linearity, and the introduction of delta-sigma modulation technology will bring additional power consumption, so this is not a perfect solution

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