Lock detection circuit for phase-locked loop

Abstract

The invention relates to a lock detection circuit for a phase-locked loop. The phase-locked loop comprises an input frequency divider and a feedback frequency divider, and the lock detection circuit comprises two input buffers, three digital lock detection modules and a majority voter, wherein one of the input buffers receives a reference signal provided by the input frequency divider and simultaneously provides reference buffer signals to the three digital lock detection modules; the other input buffer receives a feedback signal provided by the feedback frequency divider and simultaneously provides feedback buffer signals to the three digital lock detection modules; each of the digital lock detection modules compares the reference buffer signals with the feedback buffer signals; and the majority voter generates a lock detection signal based on output signals of the three digital lock detection modules. The scheme of the invention has the advantages of strong flexibility, anti-single event effect and the like.

Description

technical field [0001] The invention relates to a highly reliable integrated circuit, in particular to a lock detection circuit for a phase-locked loop. Background technique [0002] The phase-locked loop circuit is an automatic phase control system, which makes the oscillator output signal track the reference input signal through a phase negative feedback loop to obtain a low-jitter output signal. In 1932, Bellescize realized the phase-locked loop for the first time by using vacuum electron tubes. Due to the cost and technical complexity, the phase-locked loop was mainly used in the field of space technology in the early days, such as: missile beacon tracking, satellite communication, etc. It was not until the integration of phase-locked loops that they were widely used in electronic and communication systems. Today, phase-locked loops are known as the "heart" of electronic systems, and are widely used in various clock systems, including frequency synthesizers, clock data ...

AI Technical Summary

Problems solved by technology

[0006] However, when the lock detection circuit is bombarded by a single event, the lock detection signal may jump, that is, the lock detection signal is affected by the single event effect and outputs an out-of-lock signal, thereby causing misjudgment

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