PLL CIRCUIT, SEMICONDUCTOR DEVICE, ELECTRONIC CONTROL UNIT, AND CONTROL METHOD OF PLL CIRCUIT

摘要

According to one embodiment, a PLL circuit includes: a digital phase comparator that captures an instantaneous value of a reference clock signal, which is a digital since wave, in synchronization with a feedback clock signal, and detects a phase difference between the reference clock signal and the feedback clock signal based on the captured instantaneous value; a control voltage generation unit that generates a control voltage according to the phase difference; a voltage control oscillator that generates an output clock signal having a frequency according to the control voltage; a frequency divider that divides a frequency of the output clock signal to generate the feedback clock signal; and a control unit that amplifies the reference clock signal to be supplied to the digital phase comparator with an amplification factor according to the phase difference.

主权项

1. A PLL circuit comprising:
a phase difference detection unit that captures an instantaneous value of a reference clock signal in synchronization with a feedback clock signal, and detects a phase difference between the reference clock signal and the feedback clock signal based on the captured instantaneous value, the reference clock signal being a digital sine wave; a control voltage generation unit that generates a control voltage according to the phase difference; a voltage control oscillator that generates an output clock signal having a frequency according to the control voltage; a frequency divider that divides a frequency of the output clock signal to generate the feedback clock signal; and a control unit that amplifies the reference clock signal to be supplied to the phase difference detection unit with an amplification factor according to the phase difference.