Heart Rate measurement circuit implementation using AFE4490

Sathiya Seelan Sekar

Other Parts Discussed in Thread: AFE4490, AFE4403, AFE4404EVM, AFE4404

We are using IC AFE4490 (QFN Package Industrial grade) for Heart Rate Measurement Application. We need clarification on the application circuit implementation.

Reference part: In AFE4403 (BGA Package) data sheet, it is mentioned that the TX3 pin driving the Green LED is used for heart rate measurement & the IR LED, Red LED is used for SP02 pulse oximetry application. (Ref: 8.3.5.1 Third LED Support, Page 39)

But in the AFE4490 part, there is no TX3 pin available. We are using the SFH7050 as sensor interface to AFE, which has IR, Red and Green LED then Photo detector.

Please clarify us, which pins from AFE are required to drive the SFH 7050 part & also specify which color LED is to be driven for the heart rate measurement application.

Regards,

S.Sathiya Seelan

over 10 years ago

0 Amy Schnoor over 10 years ago

TI__Mastermind 18285 points

Sathiya,

We have received your post and hope to have a response back to you soon.

0 Praveen Aroul over 10 years ago

TI__Mastermind 49956 points

Hello Sathiya,

AFE4490 supports only 2 LEDs in H-Bridge or push-pull configuration. Refer to the application section 9.2.1 for possible configurations.

Using SFH7050 with AFE4490, only 2 out of 3 LEDs could be used. Depending on your application, you can choose the two LEDs and the configuration (H-Bridge or Push-pull) and connect to the TXP and TXN pins of the AFE.

0 HARINI B over 10 years ago in reply to Praveen Aroul

Intellectual 340 points

Hello everyone,

Can I know the circuit implementation of AFE4490 with SFH 7050 Biomon Sensor ?

0 Amy Schnoor over 10 years ago in reply to HARINI B

TI__Mastermind 18285 points

Harini,

The AFE4404EVM uses the SFH7050 for the sensor board. You can use that as a reference.

www.ti.com/.../AFE4404

0 HARINI B over 10 years ago in reply to Amy Schnoor

Intellectual 340 points

you don't have exact implementation of SFH 7050 with AFE4490 ?
I want the circuit description along with Source Code..
Please help me on this..
What is the role of Accelerometer Sensor in this module ?
Can I know in brief about this ?

0 Amy Schnoor over 10 years ago in reply to HARINI B

TI__Mastermind 18285 points

Harini,

No we did not use this with the AFE4490, but the implementation is very similar.

We offer source code for each of our AFE44xx devices. Those can be found under tools & software on each product folder.

The sensor board has an option to use the BMA280, which is an accelerometer. We give just give this as an option for customers who want to use this for things like motion cancellation. However, we leave it uninstalled by default.

0 HARINI B over 10 years ago in reply to Amy Schnoor

Intellectual 340 points

Can I know the accuracy of SFH7050 with AFE4490 ?
Do you have the values of the experimental data of AC and DC values of RED and IR LED's ?
And these values are from the output of the Sensor or what ?

0 Amy Schnoor over 10 years ago in reply to HARINI B

TI__Mastermind 18285 points

We do not have the exact accuracy number, but we have found it to be accurate with our AFE4404, which will be a very similar implementation. IT is one of our recommended sensors.

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Heart Rate measurement circuit implementation using AFE4490