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Phased locked loop to provide precise frequency and phase tracking of two signals

  • US 4,902,986 A
  • Filed: 01/30/1989
  • Issued: 02/20/1990
  • Est. Priority Date: 01/30/1989
  • Status: Expired due to Term
First Claim
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1. A device for use within an integrated circuit and which utilizes an external reference oscillating signal to calibrate signals within the integrated circuit, the device comprising:

  • a ring oscillator for generating a calibration signal oscillating at a first frequency which is to be matched to the frequency of oscillation of the external reference oscillating signal;

    a power source for supplying a compensated power signal to the ring oscillator, the frequency of oscillation of said calibration signal increasing when the voltage of said compensated power signal is increased, and the frequency of oscillation of said calibration signal decreasing when the voltage of said compensated power signal is decreased, the voltage of said compensated power signal being responsive to a control signal; and

    phase detector means, coupled to the power source, for receiving as input said calibration signal and said reference oscillating signal and for generating said control signal, the phase detector means varying said control signal so that said first frequency matches the frequency of oscillation of the external reference oscillating signal;

    wherein said compensated power signal is used in other portions of the integrated circuit which are critical data paths.

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