Phase-locked loop having phase detector error signal reshaping and method thereof

Abstract

A phase-locked loop includes a signal reshaper connected between a phase detector and a charge pump. The signal reshaper can be controlled by a controller to reshape the phase error signal based on the difference between the frequency of an output signal, output from a low pass filter, and a target frequency. The signal reshaper outputs a reshaped or unreshaped phase error signal to the charge pump. The unreshaped phase error signal causes the phase-locked loop to lock the frequency of a feedback signal to the frequency of an input signal. The reshaped phase error signal causes the charge pump to output a charge pump signal that synchronizes the frequency of the output signal with the target frequency.

Description

technical field [0001] The present invention provides a phase-locked loop, particularly a phase-locked loop capable of reshaping a phase error signal and related methods. Background technique [0002] Phase-locked loops have been widely used in digital electronic instruments, signal telemetry devices, and communication technologies. In these applications, phase-locked loops are widely used in clock distribution, recovery, and data demodulation. [0003] The phase-locked loop is mainly used to generate an oscillation frequency that matches the frequency of an input signal. see figure 1 , figure 1 It is a block diagram of a basic PLL 10 known in the art. The PLL 10 includes a phase detector 12 for receiving an input signal S1 and a feedback signal S2 and comparing the phase difference between them. The phase detector 12 generates a phase error signal according to the phase difference. The PLL 10 further includes a frequency detector 13 for receiving the input signal S1 an...

AI Technical Summary

Problems solved by technology

[0007] However, the known phase-locked loop still has the problem that the response time is not fast enough

More specifically, a phase-locked loop that uses both a frequency detector and a phase detector will still have frequencies in the frequency range where it cannot lock, and cannot meet the needs of faster response times

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