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Laser drive circuit

  • US 5,260,956 A
  • Filed: 09/22/1992
  • Issued: 11/09/1993
  • Est. Priority Date: 09/30/1991
  • Status: Expired due to Fees
First Claim
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1. A laser drive circuit for modulating a laser beam intensity emitted from a laser device to a maximum power and a minimum power in accordance with a first and second values of a binary signal, comprising:

  • photo-detector means for detecting the laser beam emitted from said laser device to produce a detection output signal;

    first differential amplifier means for producing a maximum error detection signal representing a difference between the detection output signal applied thereto and a maximum reference;

    second differential amplifier means for producing a minimum error detection signal representing a difference between the detection output signal applied thereto and a minimum reference,first sample and hold means for sampling and holding the maximum error detection signal at a timing of the first value of the binary signal and outputting the same as a maximum error signal;

    second sample and hold means for sampling and holding the minimum error detection signal at a timing of the second value of the binary signal and outputting the same as a minimum error signal; and

    laser drive amplifier means for controlling the maximum power and the minimum power of the laser beam emitted from the laser device in accordance with the maximum error signal and the minimum error signal.

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