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MSP430 Launchpad Power consumption

Elliott Gurrola
Prodigy 90 points

Hello all,

I was wondering what is the max current I can get out of the Launchpad VCC pin, I see there's a 250mA voltage regulator but I'm not sure how much is being "stolen" by the board circuitry, a quick estimate would be okay, I just need an idea of how much juice is available for me to use 50mA? 100mA? 200 =) ?

Thanks in advance,

Elliott

The reason why I'm asking is because I've always been into educational workshops to get freeshman students at my university started developing electronics projects. In the past I've used Atmel's MCU's to teach students, however, I recently found out about this Launchpad board and it seems that the development cost would be much lower (as an estimate 80% cheaper)

Add a small breadboard, some extra resistors/LEDs/switches/pots/etc and you've got yourself an innexpensive development kit. I'm thinking of using the workshop + kit idea as a fundraiser for our organization, the problem is the power (else I would need to add some extra parts + battery = more "expensive")

I'll probably  add a "Make the Switch entry" once I give it a try. =)

As a small suggestion, it would be nice to have footprints from the USB VCC that way we could use the launchpad as a bigger power supply, just an idea

  • 0
    Guru 227245 points

    LaunchPad draws its current from USB. And I don't think it identifies itself to the PC as a high-current device. So the total limit is 100mA. Depending on current operation (especially the LEDs), it leaves ~70mA for peripheral electronics.

  • 0 in reply to Jens-Michael Gross
    Prodigy 90 points

    I thought USB ports could provide around 500mA or is this system dependent?

  • 0 in reply to Elliott Gurrola
    Guru 227245 points

    Elliott Gurrola said:
    I thought USB ports could provide around 500mA or is this system dependent?

    Yes and no. An unused USB socket will only provide up to 100mA. Only after a device has enumerated and identified itself as high-power-device (which the LaunchPad doesn't), the HUB will allow 500mA.
    However, some cheap HUBs have 500mA and even more enabled all the time (and by plugging the USB cable in, you can shortcut their power supply, resetting all other devices on the same HUB)

    The 500mA (900 on USB3.0) are distributed power. Only 100mA are guaranteed. I tmay even be that if a different device is drawing full current, new devices get their request for 500mA denied, even if they ask for it. Not every 8-port HUB comes with a 4A supply :)

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