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Thread: Data acquisition with Teensy 3.6

  1. #1
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    Data acquisition with Teensy 3.6

    Hi all,

    I am interested in using the Teensy 3.6 to acquire signal data of a square waveform that has a peak to peak voltage (Vpp) of 80 volts. Is this do-able? If so how would you go about doing this?

    Thanks and best regards.

  2. #2
    Senior Member+ Theremingenieur's Avatar
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    Voltage divider + limiting/clamping diodes. 9th grade stuff. No rocket science...

  3. #3
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    It seems simple enough (using Ohms law). But there are a few design decisions to be made - and that makes it more interesting.

    Is 80 volts the maximum? Or might this be variable even up to a peak of 100 volts? And how fast is this square wave? (Fast might need compensation). Lots of unknowns.

    I thought about a diode clamp to the 3v3 rail... but then wondered if a zener might be preferable? Anyone got thoughts here?

    Assuming slow frequency, my design settled on the following (with a 1:40 resistor ratio to allow for spikes)...
    Click image for larger version. 

Name:	Divider001.jpg 
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ID:	14936

  4. #4
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    Quote Originally Posted by TelephoneBill View Post
    It seems simple enough (using Ohms law). But there are a few design decisions to be made - and that makes it more interesting.

    Is 80 volts the maximum? Or might this be variable even up to a peak of 100 volts? And how fast is this square wave? (Fast might need compensation). Lots of unknowns.

    I thought about a diode clamp to the 3v3 rail... but then wondered if a zener might be preferable? Anyone got thoughts here?

    Assuming slow frequency, my design settled on the following (with a 1:40 resistor ratio to allow for spikes)...
    Click image for larger version. 

Name:	Divider001.jpg 
Views:	1 
Size:	10.1 KB 
ID:	14936
    Sorry for neglecting the details. I am operating at 1 MHz with a 30% duty cycle. And yes you're correct, I am planning on sweeping the peak to peak voltage from 10 to 80 V.

  5. #5
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    I first thought your input was analogue "acquisition" (to the ADC). But on reflection, it's not clear what "data" you wish to acquire - it could be digital? At HF frequencies, the zener protection idea will probably be in trouble. They tend to be high capacitance at low zener voltages, and that will "shunt" the 1K resistor at HF. Often, test it provides the answers.

    Protecting the Teensy input directly could get messy. For that reason, I would put some low cost (sacrificial) buffer in between your signal and Teensy. If analogue, use a linear device. If digital use some logic gate.

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