Frequency detection device and method thereof

Abstract

The invention relates to a frequency detection device and a method thereof, wherein, the frequency detection device comprises a frequency converting circuit and an analog converting circuit. The invention is characterized in that the frequency converting circuit receives an input clock, and generates analog signals corresponding to the frequency of the input clock according to the frequency of the input clock; the analog converting circuit is coupled with the frequency converting circuit to receive the analog signals, and generates judging signals corresponding to the frequencies of the input clock according to the analog signals, wherein, the judging signals are used for representing frequencies intervals of the input clock.

Description

technical field [0001] The invention relates to an electronic circuit, especially a frequency detection circuit. Background technique [0002] In the application of integrated circuits (ICs), it is sometimes necessary to input different reference frequencies, and then use the input reference frequencies to complete subsequent circuit applications. For example, a phase lock loop (PLL) is a technology that receives a reference frequency and utilizes a feedback control principle to realize frequency and phase synchronization. [0003] The phase-locked loop receives an external reference frequency and keeps the frequency output by the circuit synchronized with the reference frequency. When the reference frequency or phase changes, the phase-locked loop will detect this change and adjust the output frequency through internal feedback control until the output frequency and the reference frequency are resynchronized. In addition, in the actual application of the phase-locked loop...

AI Technical Summary

Problems solved by technology

However, with the traditional method, when there are more reference frequencies to be selected, more pins need to be additionally set. For example, when there are five different reference frequencies to be selected, three additional pins must be set.

With the increasing demand for thinner and lighter electronic products, the space configuration of each pin has become very precious, so it has gradually become impossible to allow the space for additional pins to exist.

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