ADS1292R bioimpedance derivation

Tobias Johansson

Other Parts Discussed in Thread: ADS1292R

Hi,

I have a setup according to the figure below. I have no problem deriving the voltage level from both channel i.e. ECG and respiration. But how can I derive the impedance from the voltage level from respiration?

Best regards,

Tobias Johansson

/source to figure: www.ti.com/.../sbas502b.pdf

over 9 years ago

0 Brian Pisani over 9 years ago

TI__Mastermind 38745 points

Tobias,

I need to consult the biomeasurement expert on our team to give you an answer to this question. Please excuse the delay.

Brian Pisani

0 Tobias Johansson over 9 years ago in reply to Brian Pisani

Prodigy 90 points

Thanks , it is appreciated!

0 Tobias Johansson over 9 years ago in reply to Brian Pisani

Prodigy 90 points

Hi Brian,

Did you get any answer to this question?

Tobias Johansson

0 Brian Pisani over 9 years ago in reply to Tobias Johansson

TI__Mastermind 38745 points

Hello Tobias,

I apologize for the long delay in my response. I believe that the calculation is best described on page 59 of the ADS1292R datasheet. The normalized patient impedance can be found by multiplying the baseline body impedance by the modulation current (calculated as VREFP-AVSS divided by the impedance of the modulation circuit) and the product divided by 30 uA. I hope this answers your question.

Regards,
Brian

0 Tobias Johansson over 9 years ago in reply to Brian Pisani

Prodigy 90 points

Great, thank you! I missed that in the data sheet.

Best regards,
Tobias Johansson

Data converters

Data converters forum

ADS1292R bioimpedance derivation