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TMS570Lc43x power consumption

Markus Auer
Intellectual 420 points

Hello guys i have a question about this specific MCU about its power consumption,

i am using this MCU to get some sensor data (temperature sensor DS1621 pretty small one around 1mA). This data i pass to a LTE Modul from Telit (LE910-EU V2).

My usecase is that i want to use only one power supply. i thought about 12 V power supply and then it was the question how much Ampere i need.

i dont know yet what the telit modul needs right now exactly but i need also to know how much the TI MCU needs usually, or basically what is definitly necessary and what i can assume will be maximum?

in the data sheet i found something about 990mA. is that right for the maximum? and when does the controller reach this?

because as i said i will only use a little sensor or the buttons and LED on the board so far.

Would be nice if someone can help me with knowledge about getting a decision which power supply i need.

regards,

Markus

  • 0
    TI__Guru 72500 points
    Yes, 990mA is the maximum for the core (1.2V) supply. That covers the case with the CPU running at 300MHz, the core voltage is at 1.32V and the junction temperature is 150C. There is a footnote showing how you can derate that value when at different conditions.
  • 0 in reply to Bob Crosby
    Intellectual 420 points

    Hello Bob,

    and what can i assume when i just use the button and the LED turning on and off and sending over sci one c struct looking like this

    typedef struct{
    uint8 w,
    uint8 x,
    uint8 y,
    uint8 z}

    so a simple Byte struct. And if i use the temp.sensor DS1621 which only is around 1,25mA.
    1) so what can i assume approximatly for the consumption? its okay if it is overassumed. but should i assume 100mA or rather 500mA?

    2) And if i plug the MCU over USB to my Laptop. How much Volt and how much Ampere can i assume is there just in "idle" mode by doing nothing with it?

    3) Where can i find the footnote and can you make an example because it is probably confusing for me because i am not an electricity expert.

    thank you very much in advance,


    kind regards
    Markus

  • 0 in reply to Markus Auer
    TI__Guru 72500 points

    Are you asking the power consumption of the microcontroller, or of a particular board? The current required by the micro is a function of the clock speed, temperature and voltage. The footnote is on page 59 of SPNS195

  • 0 in reply to Markus Auer
    TI__Guru 68920 points
    Markus,

    You should also look at www.ti.com/.../power.page because with an efficient switching regulator, your current from something like USB at 4.6V minimum would be only around 300mA@4.6V to produce 990mA@1.2V. If you source 12V then it's even less but then it's even more critical to have a switching regulator..
    The Webench tools can help you find the right power supply for your situation. And if you get stuck there are E2E forums for the power supply designs as well...