2025-03-19 11:58 AM
Hi, I am trying to sample a low voltage signal around -100mV to 100mV. I am able to sample it with dual interleave mode of ADC giving it a 120mV DC offset with a DC supply to be able to measure the whole signal. Now I want to give an offset first and then amplify the signal right before ADC. I read that STM32L476 OPAMPs can be used for both offsetting and amplification. I enabled IN15 as OPAMP2 Output Single-Ended for both ADC1 and ADC2 and selected "Dual Interleaved Mode Only". I am kind of confused about configurations,
I am not sure how to configure OPAMP2, I need 2 things, one is to offset the signal for like 200mV(To shift it completely to positive side) and other is to amplify it. I understand that I should be able to do both from what is written in this document: https://www.st.com/resource/en/product_training/STM32L4_Analog_Opamp.pdf
I am not sure if I can set this with PGA not connected, also PB0 is for sampling the amplified signals but I am not sure what PA6 is for, I will not be amplifying my signal shifting it more than 1V so I think I also should be able to do it without giving an external bias.
I have looked through some application notes but could not exactly figure out how to set these for my needs so I appreciate any advice.