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Original question:

THS4551: Single ended source to ADS1288

THP210: Single supply design

Lkhagvajantsan Damdinsuren
Prodigy 70 points

Part Number: THP210
Other Parts Discussed in Thread: ADS127L14, ADS1288

Tool/software:

Hello Luis,

Thank you again for your support.

We have tested ADXL354 MEMS accelerometer, it worked well.

Now we are stepping to production.

We will have two sensors and 4 channels, 3 channel for accelerometer ADXL354 and 1 channel for geophone.

I think we will use THP210 and ADS127L14 (for all 4 channels).

My circuit for geophone has dual supply, i.e +-5V as below.

Please advice me can we make geophone circuit below single supply?

I have an circuit idea from ADS1288 datasheet page 45.

Best regards,

Lhagva

  

  • 0
    TI__Mastermind 29118 points

    Lhagva,

    The most common way to convert a dual supply to single supply is to replace all the ground references with a mid supply reference.  The mid supply is now acts as an analog ground.  The op amp negative power supply would then connect to the system ground (i.e. GND = 0V).  See original circuit below and single supply version.

    New version:

    Old version:

    Files:

    geo-dual-sup.TSC

    geo-single-sup.TSC

    Best regards, Art

  • 0 in reply to Art Kay
    Prodigy 70 points

    Hello Art,

    Thank you very much for your reply.

    I will use TI DIYAMP-SOIC-EVM evaluation boards.

    The user's guide SBOU162A.pdf page 9 and page 10 mentions schematics for Sallen key filter and Non inverting amp as below.

    Can we use this configuration.

    Best regards,

    Lhagva

    sbou162a DIYAMP-SOIC-EVM.pdf

  • 0 in reply to Lkhagvajantsan Damdinsuren
    TI__Mastermind 29118 points

    Lhagva,

    That is a good find.  Yes, definitely use that and you can confirm it meets your requirements with the EVM.  

    Best regards, Art

  • 0 in reply to Art Kay
    Prodigy 70 points

    Hi Art,

    I did simulation.

    The first stage is fine and has DC voltage 2.5V at the output.

    But the second stage goes to almost 5V (4.962V exactly).

    Please advice me how to fix it.

    I would be happy if you provide me with the documentation for single supply design.

    Best regards,

    Lhagva 

  • 0 in reply to Lkhagvajantsan Damdinsuren
    TI__Mastermind 29118 points

    Lhagva,

    1. Here is a reference for single supply design:  sloa030a 
    2. The problem with that reference is that it doesn't really cover your specific circuit.  The more unusual you make the circuit, the less likely you are to have a specific example for that circuit.  Based on your comment it seems that the DIYAMP-SOIC-EVM document helped you get the first stage to work.
    3. For the second stage, I can help you with that but I need to know what your specific goal is.  The circuit has an inverting connection back to the input and an non-inverting connection.  What input output relationship do you want?  What is your input signal range from the first stage and what output do you want.
    4. When I do single supply design I do what I mentioned in a previous post.  That is, I ground the negative supply and take all other grounds and place them at mid supply.  If you do this you can take any generic circuit and convert it to single supply.

    Sorry I don't have a specific circuit for the answer, but I don't what to guess at what your goal is.

    Best regards, Art