Ladungspumpe für einen Phasenregelkreis

Charge pump in a phase lock loop

Pompe de charge dans une boucle à verrouillage de phase

Abstract

A charge pump (16) in a phase lock loop equalizes the charge and discharge currents flowing into the filter capacitor (20) independent of the loop node voltage for providing a linear VCO output frequency. The potential at the output of the charge pump determines whether the charging/discharging current is decreased or increased. An active up control signal to increase VCO output frequency and a low level potential at the output of the charge pump limits the charging current to the loop filter while increasing the discharge current. An active down control signal to decrease the VCO output frequency and a high potential at the output of the charge pump limits the discharging current while increasing the charge current. The voltage change at the output of the charge pump in response to the up control signal is made equal to the voltage change during the down control signal for providing equal charge and discharge currents to the loop filter independent of the loop voltage.

Claims

Description

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Patent Citations (4)

    Publication numberPublication dateAssigneeTitle
    EP-0334980-A1October 04, 1989Deutsche ITT Industries GmbHFilterschaltung
    EP-0415649-A2March 06, 1991Delco Electronics CorporationCompensated phase locked loop circuit
    JP-H01177867-AJuly 14, 1989Nec Corp, Nec Eng LtdCharge pump circuit
    JP-H0263219-AMarch 02, 1990Nec Corp, Nec Eng LtdCharge pump circuit

NO-Patent Citations (3)

    Title
    "DIFFERENTIAL CHARGE PUMP", IBM TECHNICAL DISCLOSURE BULLETIN., vol. 33, no. 9, February 1991 (1991-02-01), NEW YORK US, pages 332 - 333, XP000109567
    PATENT ABSTRACTS OF JAPAN vol. 13, no. 459 (E - 832) 17 October 1989 (1989-10-17)
    PATENT ABSTRACTS OF JAPAN vol. 14, no. 239 (E - 930) 21 May 1990 (1990-05-21)

Cited By (15)

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    DE-19713058-C2September 13, 2001Mitsubishi Elec Semiconductor, Mitsubishi Electric CorpPLL-Schaltung
    EP-0881774-A2December 02, 1998Nec CorporationPhase locked loop using a Schmitt trigger block
    EP-0881774-A3June 09, 1999Nec CorporationPhase locked loop using a Schmitt trigger block
    EP-1292032-A1March 12, 2003Mitsubishi Denki Kabushiki KaishaSynchronous device
    EP-1292032-A4August 20, 2003Mitsubishi Electric CorpSynchrone vorrichtung
    US-5912575-AJune 15, 1999Mitsubishi Electric Semiconductor Software Co., Ltd., Mitsubishi Denki Kabushiki KaishaPhase-locked loop circuit with charge pump and time constant circuit
    US-6043695-AMarch 28, 2000Nec CorporationPhase locked loop using a schmitt trigger block
    US-6812754-B1November 02, 2004Renesas Technology Corp.Clock synchronizer with offset prevention function against variation of output potential of loop filter
    US-6864723-B2March 08, 2005Broadcom CorporationHigh-swing transconductance amplifier
    US-6873194-B2March 29, 2005Broadcom CorporationCharge pump including a feedback device for use in a phase-locked loop
    US-7005902-B2February 28, 2006Broadcom CorporationCharge pump including a feedback device for use in a phase-locked loop
    WO-0227923-A2April 04, 2002Broadcom CorporationHigh-swing transconductance amplifier for charge pump circuit
    WO-0227923-A3September 06, 2002Broadcom CorpAmplificateur de transconductance de forte oscillation pour circuit de pompage de charge
    WO-9614690-A1May 17, 1996National Semiconductor CorporationCircuit de pompe de charge a commutation par cascode