Clock generator for generating accurate and low-jitter clock

Abstract

A clock generator has a clock generating circuit, a phase difference detection circuit, and a control signal generating circuit. The clock generating circuit has a function for varying a clock phase in accordance with a control signal. The phase difference detection circuit compares the clock phase output from the clock generating circuit with a phase of a reference waveform, and detects a phase difference therebetween. The control signal generating circuit generates a control signal for controlling the clock phase of the clock generating circuit, based on phase difference information obtained from the phase difference detection circuit. The phase difference detection circuit has a plurality of phase detection units. At least one of the plurality of phase detection units carries out a direct phase detection in which a phase of the clock is directly compared with the phase of the reference waveform, and at least the other one of the plurality of phase detection units carries out an indirect phase detection using a phase-synchronized waveform generating circuit generating a waveform synchronized in phase with the reference waveform or an output of the clock generating circuit and a phase information extracting circuit extracting phase information from the phase-synchronized waveform.

Description

technical field [0001] The invention relates to a signal transmission technology capable of realizing high-speed signal transmission between multiple LSI chips or between multiple devices or circuit groups in a single chip, or between multiple boards or cabinets, and specifically relates to a A clock generator for high bit rate signaling. Background technique [0002] Recently, the performance of various components used in computers and other information processing equipment has been greatly improved. In particular, for example, the performance of semiconductor memory devices such as SRAM (Static Random Access Memory) and DRAM (Dynamic Random Access Memory) and other semiconductor devices such as processors and switching LSIs has greatly improved. [0003] The improvement in performance of semiconductor memory devices, processors, etc. has reached a point where system performance cannot be further improved unless the signal transmission speed between components or elements ...

AI Technical Summary

Problems solved by technology

Also, the speed of signaling between peripherals and the processor / chipset is becoming a major factor limiting overall system performance

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