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TDC1000-C2000EVM: amplifying TDC1000-C2000EVM TX signal disables RX signal

Swapnil Patel
Intellectual 635 points
Part Number: TDC1000-C2000EVM
Other Parts Discussed in Thread: TUSS4440, TUSS4470, PGA460, TDC1000

Hi,

I am currently using TDC1000-C2000EVM board with 1 Mhz transducer and is able to excite is properly and see echo back on RX side.

However, I wanted to amplify the TX signal strength. 

I am doing this by adding high voltage drive circuit from http://www.ti.com/lit/df/tidrbi0/tidrbi0.pdf to my TDC1000-C2000EVM. 

Currently this is added as a plug in board between output of the TDC1000-C2000EVM (J5) and transducer. 

But when I plugin my high voltage circuit, I can't see any echo back on my RX signal. I am trying to monitor this at TP12 as well as on TDC1000-C2000EVM at compin test point.

Any help would be greatly appreciated.

Thanks! 

  • 0
    TI__Mastermind 27950 points

    Swapnil,

    How do you have your transducer connected, and do you have R80 and/or R81 populated on the TDC1000-C2000 EVM?

    You should probe each stage of the receiver path to determine where the signal loss occurs: RX1/2, LNAOUT, PGAIN, PGAOUT, and COMPIN.

    The TDC1000-C2000EVM was designed to support a pre-driver voltage to drive transducers upwards of 30V. If you require a larger transducer voltage, I recommend that you use a transformer based ultrasonic IC, such as the PGA460 or the TUSS4440. Even the full-bridge driver of the TUSS4470 ultrasonic IC can support up to 36V.

    Depending on your ultrasonic application use-case, we have specific part number recommendations as discussed in the Ultrasonic E2E FAQ: https://e2e.ti.com/support/sensors/f/1023/t/748143 . Is there a reason you need to use the TDC1000 specifically? If you can provide some details on your ultrasonic application, I may be able to provide a specific part number and register setting solution.

  • 0 in reply to Akeem Whitehead
    Intellectual 635 points

    Hi,

    thank you for response!

    I have R80/R81 populated fine. The EVM board works fine when I disconnect my HV amplifier board. 

    And I can't see any signal back at the very beginning. (TX/RX pin connecting to the transducer). 

    I am trying to use ultrasonic to as distance sensor through oil.  Is there any alternative to TDC1000 that you recommend for that kind of application?

     again, thank you for your help.

    Thanks! 

    Swapnil 

  • 0 in reply to Swapnil Patel
    TI__Mastermind 27950 points

    Swapnil,

    Depending on the frequency of your transducer, and the required transducer drive voltage to generate sufficient sound pressure level, the PGA460, TUSS4470, or TUSS4440 are feasible alternatives to the TDC1000 for oil level sensing. Can you provide the part number and/or the aforementioned specifications of your transducer?

    Since you are measuring through oil, I assume you are mounting the transducer to the bottom of the oil tank for it to face upwards, so you will likely need a large driver voltage, so PGA460 or TUSS4440 may be the better options.

    What is the size of the oil tank, and what is the minimum and maximum oil level in distance you need to be able to measure?