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envelope detector

Aldo Gonzalez
Prodigy 60 points
Other Parts Discussed in Thread: OPA4377

Hello friends!!!, I am Aldo from Buenos Aires. I am looking for an good and precision audio signal envelope detector. I was testing some circuits from internet, but finally none work very well. Somebody can recommend to me some circuit that really works ???.

My email is aldohgonzalez@gmail.com

thank you very much.

  • 0
    TI__Genius 14317 points

    Hi Aldo,

    Thanks for using the TI E2E Forums!

    This is from a previous discussion on this very subject:

    Envelope detection can be accomplished with an op amp based precision rectifier, but often the simple diode detectors are sufficient for general applications. If precision detection is required, then take a look at the TI Precision Design (TIPD) for a precision rectifier:

    http://www.ti.com/tool/tipd139

    This will provide you some idea as to what is required to attain precision performance. The ac performance of the operational amplifier must be correct for the application. You will note that the op amps in the TIPD are higher current, wide bandwidth amplifiers. The low power requirement must be kept in perspective in relation to the ac performance requirements.

    National Semi had various precision rectifier circuits in some of their operational amplifier data sheets. A Google search will show some alternative circuits for the LF353 and the LM301.

  • 0 in reply to Jeffery Pfarr
    Prodigy 60 points
    Hi Jeff, nice to write you, and thank you for the information you sent me, but it´s not I am looking for. I need the envelope detector copy exactly the border or the waveform, like this jpg I send you.. I am simulating your circuit in Multisim, an it do not work as I like.
    Regards

    2.bp.blogspot.com/.../chi2.jpg
  • 0 in reply to Aldo Gonzalez
    TI__Genius 14317 points

    Hello Aldo,

    Take a look at Fig 2 in the attached .pdf which shows a L/R audio envelope circuit that's used as part of an audio envelope tracking power supply design. If your design uses only one channel, then you could eliminate one of the input OA circuits and make the output stage a non-inverting unity gain stage. The OPA4377 is a quad OA so the whole circuit would require only one device plus diodes and passives. You might want to do some gain scaling of the input stage and use +/- supplies if available. The input is AC coupled.

    tidual0.pdf