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TMS320F28335: Estimating power consumption of microcontroller

Rohit Baranwal
Expert 1025 points
Part Number: TMS320F28335

Hi,

I am trying get an estimate of the power consumption of the microcontroller on a F28335 based board. As it stands, I have following I/Os and peripherals connected on the board:

1. 12 GPIOs configured as 12 PWM channels

2. 16 GPIOs configured as inputs (connected to buffers)

3. 8 GPIOs configured as outputs (connected to buffers)

4. Two SCI modules

5. SPI module

6. All 16 ADC channels

7. One eCAP module

Other GPIOs are left floating and configured as outputs.

In a typical usage scenario, following I/Os are being used for the target application:

1. 8 PWM channels

2. One SCI module

3. 8 digital inputs

4. 1 eCap module

5. 7 ADC channels

6. SPI module

Based on the above, is there a way to approximate the power consumption of the processor? I do not need an exact figure, but something in the ballpark would be ok. An answer such as <100mW or <200mW or something similar is what I am looking for. Can somebody help?


If any other information is needed to get an estimate, I can try to provide that.

  • 0
    Guru 192875 points
    Hi Rohit,

    The best way to estimate the same would be to power the controller externally through a LAB Power Supply. Also, you can go through Section 6.4 Current Consumption in datasheet.

    Regards,
    Gautam
  • 0
    Guru 30330 points
    Rohit,

    You can calculate this estimation yourself using the device datasheet (SPRS439). Using Table 5-1, take the operational current numbers for the each supply, and calulate the total power consumption. You can compare your usecase against the peripherals listed in the test conditions column and then subtract the current for each peripheral you are not using by looking at Table 5-3 Typical Current Consumption by Various Peripherals (at 150 MHz).

    This should give you a rough estimate of the total power consumption of the device. You can add margin on top of that so you ensure your power supply can handle the loads well. Doing some characterization of your power consumption after your system is designed will help you fine tune your numbers. If you have a development kit, you can, as Gautam mentioned, power your device with a lab power supply and measure the current consumed either by your actual application code (later in the development process) or with some representative code using the modules you will be using.

    As the number of applications and usecases are so vast, it is not feasible for us to do much more than guide you through the process to do the legwork for your specific case. If we supplied power estimates to every customer who requested it, I don't think we would ever get around to making more innovative chips! :)

    Please let me know if you have any more questions.
    -Mark