I am currently in the process of trying to implement a ADE7753 in a single-phase energy meter. However, as a fallback, I am also considering using a teensy 3.0 because of its fast quasi-13 bit adc.
Unlike the ADE7753, the teensy uses a single-ended adc whose input is positive-only. I could follow in the footsteps of the energy monitor project as I have in the past ie have a strong dc bias get wobbled by the attenuated transformer output.
But I also ran across differentiating op amps as another potential solution to turn an AC signal from the transformer (+- 5V) into a DC-biased signal suitable for the teensy, ie 1.65V +- 1.5V since the teensy is limited to 3.3v on its adc inputs.
What are your thoughts on using an op-amp for this sort of application? Is it overkill when sampling line frequencies?
As a second question, when it comes to monitoring the output of a transformer, should I built a voltage divider using resistors that results in the right input range for the op amp, or is it better to choose among the few differentiating op amps that are designed for attenuation to do the same?
Many thanks for all the insights you can share, Constantin