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how to configure AFE4400's the LEAST CURRENT?

Now the least current I set  is 25mA, when the current is least current, the SpO2 would be wrong. And it test on Fluke' simulator.I tried to test different SpO2 value,and if the current is 25mA or lower,the calculation results of SpO2 are all nearby 80%.And I set the least current to 3mA or higher,then the SpO2 would be right.

  • User,

    Let me make sure I understand. You are trying to measure SPO2 and accuracy is your first priority. Then you second priority is having the least current as possible?

    If this is true, I would try to get your settings to where you are obtaining accurate results. Then, reduce the current slightly while increasing the gain settings and other knobs. Continue to do this until you get what you need.

    Keep in mind each subject is different so the same settings will not work for everyone.
  • Amy,
    The way used to change current and gain is: First ,I set current and gain all highest ,then I read the ADC value, if the value is higher than 1000000,I would reduce current.Second, and if current is lower than 25mA,I would reduce gain to 1/2 of last value, and increase current to 50 mA. But I found when the status is the 27mA or lower,the Fluke' simulator testing would be wrong, but my body testing would be right.So I condsider if the led current can't be lower than a certain value