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TPA3116D2: Can it drive telephone pick-up coils (R=280 Ohm, L=159mH) as "speakers"?

Henrik Rosenø
Prodigy 170 points
Part Number: TPA3116D2
Other Parts Discussed in Thread: TPA3255, TAS5828M, TAS5827, TAS5805M

Hi!

I am planning an experiment where I need to "play" white noise into coils, in order to create a short ranged multi frequency electromagnetic field.

According to my sources, this can be done by sending the white noise into telephone pick-up coils. I already have 2 from Monacor, with resistance R=280 Ohm and inductance L=159mH. So my question is if the TPA3116D2 audio amplifier can drive them as "speakers"?

The TPA3116D2 IC has been implemented in a neat and practical audio amplifier ZK-1002T - that I already have - see here:

https://www.amazon.com/DAMGOO-Bluetooth-Amplifier-Wireless-Installation/dp/B088BP48Z9/

PS: I tried posting this question as a related question to this question:

https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1276275/which-ina-needed-up-to-24-khz-input-2-x-1-kohm-impedance-coils-output-audio-mic-or-line-signal

But that was not possible...! The form insisted that I type a Part Number, while at the same time blocking any input to that same field... I REAL Catch 22! :-)

  • 0
    TI__Genius 14420 points

    Hello Henrik,


    There might be limitations given the max PVCC on TPA3116D2 is 26V when you are trying to drive high impedance loads depending on your output voltage needs and given this is a very high impedance load the output current would be quite small, additionally our devices requires an L-C filter to get a traditional audio waveform but could have effects depending on what the desired output is on the telephone coil. Would recommend validating the functionality with an EVM with your desired load since this is an atypical application.

    best regards,
    Luis

  • 0 in reply to Luis Fernandes de Pina
    Prodigy 170 points

    Thank you for your reply!

    I am not sure what you mean by "our devices requires an L-C filter to get a traditional audio waveform"?

    Which kind of EVM are you thinking about, to evaluate telephone pick-up coils as "speakers"?

    The TPA3116D2 based amplifier ZK-1002T is kind of an EVM. ;-)

  • 0 in reply to Henrik Rosenø
    TI__Genius 14420 points

    Hello Henrik,


    Class-D Amplifier outputs are PWM but using a low-pass L-C filter you attentuate the switching noise allowing the audio signal to pass through the output. We typically recommend using TI EVMs in evaluation as we have more detailed documentation such as providing the schematic and component selection compared to a system you buy online and our EVMs allow for easier debug and performance evaluation. However you can test the system you purchased with your desired loads but note the comments i made previously.

    best regards,
    Luis

  • 0 in reply to Luis Fernandes de Pina
    Prodigy 170 points

    OK! The TPA3116D2 based amplifier was the first I found. :-)

    But are there other types of amplifiers that would be more appropriate for my unusual purpose? :-)

  • +1 in reply to Henrik Rosenø
    TI__Genius 14420 points

    Hello Henrik,

    We don't have any specific device for your purpose. TPA3255 is our highest power device, TPA3139 is a fairly recent analog input device. If you want a digital input device the TAS5805M, TAS5827, TAS5828M are options depending on the output power needs. 

    best regards,

    Luis

  • 0 in reply to Luis Fernandes de Pina
    Prodigy 170 points

    Thank you very much for you reply! :-)