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Phase frequency detector and phase-locked loop circuit

A technology of frequency and phase detectors and frequency dividers, which is applied in the field of circuits and can solve problems such as the dead zone effect of frequency and phase detectors

Pending Publication Date: 2022-05-13
SHENZHEN HENGCHANGTONG ELECTRONICS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In view of the above technical problems, the present invention provides a frequency and phase detector and a phase-locked loop circuit to solve the problem of the dead zone effect in the frequency and phase detectors in the prior art

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  • Phase frequency detector and phase-locked loop circuit
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Embodiment Construction

[0014] Typical embodiments that embody the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention is capable of various changes in different embodiments without departing from the scope of the present invention, and that the description and illustrations therein are illustrative in nature and not limiting. this invention.

[0015] In the description of the present invention, it should be understood that the terms "first" and "second" are used for description purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of said features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0016] In the description of the p...

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Abstract

The invention discloses a phase frequency detector and a phase-locked loop circuit, the phase frequency detector comprises a first D trigger, a second D trigger, a time delay unit and an AND gate, the D end of the first D trigger is connected with a power supply, the CLK end of the first D trigger is connected with a reference frequency signal input, the Q end of the first D trigger is a control signal output end, and the Reset end of the first D trigger is connected with the output end of the time delay unit; the D end of the second D trigger is connected with the power supply, the CLK end is connected with feedback signal input, the Q end is a control signal output end, and the Reset end is connected with the input end of the delay unit; the input end of the delay unit is connected with the input end of the AND gate; and the output end of the AND gate is respectively connected to the Q ends of the first D trigger and the second D trigger. According to the phase-locked loop, the dead-zone effect of the phase discriminator is comprehensively overcome through the simple and very low-cost technical scheme, the overall performance of the phase-locked loop is improved, and the cost and complexity of the phase-locked loop circuit are effectively reduced.

Description

technical field [0001] The invention relates to the technical field of circuits, in particular to a frequency and phase detector and a phase-locked loop circuit. Background technique [0002] The function of the phase frequency detector (PFD) is to compare the external input reference signal (fref) with the feedback signal (ffb) output by the frequency divider in the system, detect the frequency difference and phase difference of the two input signals, and The phase difference is converted into UP and DN signals in the form of pulses, which are used by the charge pump in the subsequent stage. The basic structure of PFD is composed of D flip-flop and AND gate with reset terminal (Reset). DN outputs a high level through the AND gate, which is transmitted to the reset terminal of the D flip-flop, and UP and DN are set to zero at the same time. In theory, the time for DN to be high level is infinitesimal, so DN is approximately all low level. When the phase of the feedback si...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03L7/085H03L7/089H03L7/099H03L7/18
CPCH03L7/085H03L7/0891H03L7/099H03L7/18
Inventor 沈冰亮
Owner SHENZHEN HENGCHANGTONG ELECTRONICS CO LTD