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Thread: Tennsy 3.2 Input Current

  1. #1

    Tennsy 3.2 Input Current

    Hello. I am doing a project that involves powering the teensy 3.2 from the Vin pin. We are using a 12V DC voltage source which is then fed into a voltage regulator. My friend originally was using a voltage regulator that supplied 5V up to 1A. The datasheet for that LDO is found here. I thought that this could potentially damage the teensy with too much current, and found another LDO that provides 5V at 150mA. The datasheet for that device is found here.

    My question is: is there a valid reason for me to switch from my friend's regulator to mine? And is there a maximum input current that Vin can take? The system was working with the old LDO but when I showed this project to an experienced EE he said that I should look into getting a new regulator since the old one was capable of producing a lot of current.

    Thanks for the help as always!

  2. #2
    Senior Member
    Join Date
    Jul 2020
    Current only flows when the load demands it. A 50A regulator isn't going to damage a 1mA part(!) - but if the voltage was
    too high, that's a different matter...

    The 78xx series is not an LDO regulator, its the original high-drop out regulator family, requiring perhaps 2V of headroom,
    but this doesn't matter if you are regulating 12V down to 5V.

  3. #3
    Oh, I see. So how much current does the teensy draw normally? I guess I should be more concerned if the regulator supplies enough current instead of supplying too much current.

    The current from my voltage regulator is also split between several sources including a solenoid, fan, LCD, and the teensy. I guess it would actually be important that my voltage regulator can supply a decent amount of current since it will be split between several different components, right? I have included a photo of my schematic for reference.

    Click image for larger version. 

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  4. #4
    Junior Member
    Join Date
    Jan 2021
    Hi Maxwell,

    I am looking for ways to power my teensy 3.2 with an octoboard safely. What was your result using these regulators and can you tell me what regulator works best?

    Best, Rob

  5. #5

    Hello. Thanks for your interest in my project. Currently, I have been experimenting with the first voltage regulator I mentioned which outputs 5V at 1A. That has been working really well for me, and I have been able to power the teensy, a solenoid valve, an LCD, a fan, and a flow meter all from that. As mentioned above, I think the key is getting a regulator that outputs enough current to feed all your devices. The best way to do this is to look at each of the datasheets for all your parts, and then double-check with a multimeter when you're prototyping. I will tell you from my very quick tests my teensy 3.2 is drawing about 25-35 mA when everything is running properly. Everything else has been drawing the expected current listed on their respective datasheet.

    Hope this helps!


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