AFE4900: Sample ppg signal

user5320919

Part Number: AFE4900

Hi,

AFE4900 has 4 leds and 3 pds, led3 or led4 is used to sample ambient light, but I want to use 4 leds to sample ppg signal , is there any problem?

over 6 years ago

0 Praveen Aroul over 6 years ago

TI__Mastermind 49916 points

Hi,

Welcome to TI E2E forum!

There are no restrictions from the AFE point of view.

However please refer to section 8.3.1 in the datasheet for system-level implications in using the 4th LED.

0 user5320919 over 6 years ago

Prodigy 150 points

Hi,

If I use all 4 leds to sample ppg siganl, ambient can't be acquired; so how much is Iamb?

0 Praveen Aroul over 5 years ago in reply to user5320919

TI__Mastermind 49916 points

Hi,

If you cannot measure ambient current, then you may not be able to use the Iamb in your calculation which may not yield accurate results depending on certain conditions like high ambient light environment etc.

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AFE4900: Sample ppg signal