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IWR6843AOP: Power Consumption

Parker owen
Prodigy 55 points
Part Number: IWR6843AOP

I am trying to reduce the power consumption of the device. Right now I am using the IWR6843AOPEVM with the break away section removed. I have it configured to have a chirp duration of 28us, using all 3 TX antennas, with 32 loops, and a burst period of 25ms. By my math this means I should be running at about 10.8% duty cycle ( 3*32*0.028/25 = 0.108). Based on this chart from the data sheet I should be seeing a power draw of around 1 watt for the device. However, when I measure the power draw of the radar I typically get 2.1 watts before I start the sensor and then 2.41 when the sensor is active. Is this typical of what the sensor should be drawing and how can I reduce the power consumption?

  • 0
    Prodigy 55 points

    Quick update to my question. I found this note in the thermal design guide that says the radar the other 4 IC's on the mission PCB will dissipate another 0.5W-1.0W. This would explain the extra watt of power draw I was seeing in my test, however, I don't believe that the other devices are using that much power.

    Here are the specs from their data sheets.

    U1 PMIC: Assuming the radar is pulling 1.15W according to the data sheet the buck reg should be running at around 85% and therefore dissipating 172.5mW.

    U2 Radar: Assuming 25% duty cycle 1.15W.

    U3 USB to UART: According to it's data sheet it will pull at most 20mA. 3.3V * 20mA = 66mW

    U9 FLASH: Assuming worst case it can draw 3mA. 3.3V * 3mA = 9mW

    U18 UART MUX: According to it's data sheet it's only ever drawing nano Amps so I'll just call it negligible.

    Assuming all of this it only brings our total power consumption up to 1.38W so we still have about a Watt unaccounted for. Where is this extra Watt of power going?

  • 0 in reply to Parker owen
    TI__Mastermind 23725 points

    Hello

    On which rails are you measuring the power consumption and what kind of measurement equipment are you using to do the same?

    Thank you,

    Vaibhav

  • 0 in reply to Vaibhav Mahimkar
    Prodigy 55 points

    I am measuring voltage and current on the 5V line of the USB cable with the breakaway section of the PCB removed. I have mostly been using a fluke multimeter to measure the power consumption but I have used a few different multimeters and radar EVMs to verify my results.