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TM4C1294 Launchpad current consumption

Other Parts Discussed in Thread: TM4C1294NCPDT, TPS2052B

I am including the TM4C1294 Launchpad in one of my designs, and I want to make sure I have enough capacity on my chosen power supply for the launchpad (as well as other components in my system). I just need to know the max and/or typical current consumption when powered from the 5V BoosterPack.


I've seen some specs for the chip itself (such as Tables 27-63 and 27-64 in the Tiva TM4C1294NCPDT Microcontroller datasheet), but I want to know what the overall launchpad is capable of drawing. Given that the two main components appear to be the microcontroller and the TM4C123GH6PMI, would it be appropriate to simply add their max consumptions together? Or are their other components on the launchpad that would draw non-trivial (ie higher than uA range) current?

I also see in the Launchpad datasheet that both the 5V and 3.3V output from the BoosterPacks are limited to 1A total, regulated by the TPS2052B and TPS73733, respectively, which I could do the calculations for with efficiency, etc., and add that to the consumptions of the two microcontrollers.


Rather than doing my own calculations, I'd prefer if there was just an existing spec for the launchpad I could use, but I don't see one. Any help would be appreciated.

Thanks,

Mike

  • Hello Mike

    LaunchPads are "NOT" production designs. So if you make a commercial product out of it there is no TI liability. The simplest method to measure current is to load your program. Then remove the header on JP1 and connect a 5V supply with common GND to the Launchpad and measure the current using a multimeter (average current samples).

  • Hi Amit,

    Understood. When I said "design," I simply meant the thing I'm putting together - it's for preliminary testing, not a commercial product. Even so, I still want to make sure my power supply is appropriate. From your answer, it appears that there is no spec listed in a datasheet somewhere, and I'll just have to wait until the program is completed before I'll be able to determine how to appropriately size the supply that will be used to power it. Is that correct?
  • Hello Mike

    The LaunchPad is not spec'ed as the choice of components affect the current consumption. As an example, the ICDI micro on the board is not required and a user can instead use an off-board JTAG debug probe. That would save a lot of current.
  • I see what you're saying, but I'm not necessarily interested in how current consumption could be affected based on optional functionality - I'm just interested in knowing the maximum current consumption possible that the overall launchpad could be using. The example of a user choosing to use an off-board JTAG would affect the ability to provide a "typical" consumption spec (as who is to say what is typical or not in a system with such variability), but most electronic devices I've seen over the years provide at least a maximum consumption spec as a worst-case scenario. I was hoping such a spec would be provided for the launchpad, but I will assume that no such max spec exists, and I will have to measure it or approximate it with my own calculations.

    Thank you for your replies - they have been informative.
  • Hello Mike

    It completely depends on what use case you are executing on the device. In the safest terms you may add up the Max current for both the TM4C devices and then divide it by the efficiency of the LDO i.e, if the efficiency of the LDO is 60%, then Current/0.6 as the input to the LDO.

    We do not provide the same for the LaunchPad as it always meant to be an evaluation board.