Delay-lock loop circuit for clock synchronization

Abstract

PURPOSE: To solve problems, such as instability in case of acquiring synchronism and a long start time after resetting. CONSTITUTION: When a clock signal VOUT is distributed among a large number of loads and a phase detector 21 detects phase difference between a clock signal and a reference signal REF, a capacitor C in a low-pass filter is charged in time consistent with the reference signal, so that a delay circuit 40 can be provided at a loop circuit for sending back a control voltage VCTRL to a veritable delay line 20 for passing the clock signal before distribution and a delayed reference signal 10 can be generated by delaying the reference signal timewise. Further, the phase detector 21 detects a phase difference between the reference signal and the clock signal, detects the phase difference between the delayed reference signal, and the clock signal and generates plural output voltages VC and VC'. By providing a logic circuit 30 and regulating the control voltage, a variable delay line is driven. COPYRIGHT: (C)1992,JPO

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Cited By (8)

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    US-6081147-AJune 27, 2000Fujitsu LimitedTiming controller and controlled delay circuit for controlling timing or delay time of a signal by changing phase thereof
    US-6259290-B1July 10, 2001Kabushiki Kaisha ToshibaDelay locked loop having a mis-lock detecting circuit
    US-6333657-B1December 25, 2001Fujitsu LimitedTiming controller and controlled delay circuit for controlling timing or delay time of a signal by changing phase thereof
    US-6420922-B1July 16, 2002Fujitsu LimitedTiming controller and controlled delay circuit for controlling timing or delay time of a signal by changing phase thereof
    US-7119595-B2October 10, 2006Fujitsu LimitedTiming controller and controlled delay circuit for controlling timing or delay time of a signal by changing phase thereof
    US-7368967-B2May 06, 2008Fujitsu LimitedTiming controller and controlled delay circuit for controlling timing or delay time of a signal by changing phase thereof
    US-7633326-B2December 15, 2009Fujitsu Microelectronics LimitedTiming controller and controlled delay circuit for controlling timing or delay time of a signal by changing phase thereof
    WO-9916078-A1April 01, 1999Hitachi, Ltd., Hitachi Ulsi Enginnering Corp.Composant de circuit integre synchrone