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Light-emitting element driving device

  • US 6,967,978 B2
  • Filed: 07/08/2003
  • Issued: 11/22/2005
  • Est. Priority Date: 12/12/2002
  • Status: Expired due to Term
First Claim
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1. A light-emitting element driving device comprising:

  • a first control unit adapted to control a drive voltage applied from a voltage source to a light-emitting element;

    a second control unit adapted to control a drive current supplied from a current source to said light-emitting element;

    a test current supply unit adapted to supply a test current to the light-emitting element when the light-emitting element is switched off; and

    a bias voltage setting unit adapted to set a bias voltage applied to the light-emitting element on the basis of a terminal voltage of the light-emitting element supplied with the test current from the test current supply unit when the light-emitting element is switched off,wherein, the first control unit and the second control unit controls an light intensity of a light beam emitted from the light-emitting element.

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