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LED forward voltage estimation in pulse oximeter

  • US 20050187450A1
  • Filed: 02/25/2004
  • Published: 08/25/2005
  • Est. Priority Date: 02/25/2004
  • Status: Active Grant
First Claim
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1. A pulse oximeter comprising:

  • at least one light emitting diode (LED) drive circuit;

    a current measuring circuit for measuring a current through said LED;

    a controller for generating a pulse width modulator (PWM) drive signal to said LED; and

    a processor, coupled to said controller and to said current measuring circuit, configured to determine if a forward voltage of said LED is within a predetermined range using a measurement of said current and said PWM signal.

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