IWRL6432: Current spike at first chirp in frame

Wolfgang Wendler TI

Intellectual 2310 points

Part Number: IWRL6432

Tool/software:

Hi team,

Asking on behalf of a customer:

We have been measuring current consumption on our IWRL6432 custom board.

The first chirp in each frame has around 50mA higher peak current consumption than the other chirps in the frames.

Why is that?

We have tried other configs but we still se the current spike in the first chirp of the frame.

Below are measurements(red graphs) of the current consumption for the IWRL6432 AOP when chirping in different time resolutions.

The chirp config in this case is:

sensorStop 0

chirpComnCfg 8 0 0 128 1 15 1

chirpTimingCfg 200 24 0 25 61

channelCfg 3 3 0

frameCfg 64 0 250 1 100 0

factoryCalibCfg 0 0 40 0 0

lowPowerCfg 0

sensorStart 0 0 0 0

Thanks,

/ Wolfgang

10 months ago

0 Blake Kisshauer 10 months ago

TI__Expert 4360 points

Wolfgang,

This is likely caused by a vco internal calibration at the start of a frame. This is why it appears strongly on the first chirp.

Thanks and Happy Thanksgiving.

Blake

0 Wolfgang Wendler TI 10 months ago in reply to Blake Kisshauer

TI__Intellectual 2310 points

Thanks Blake! I'll share with my customer.

Happy Thanksgiving to you!

Best,

/ Wolfgang

0 Wolfgang Wendler TI 9 months ago in reply to Wolfgang Wendler TI

TI__Intellectual 2310 points

Hi Blake,

Customer came back with this follow up question:

Will the VCO calibration always be at the start of every frame and will it always draw this amount of extra current? I.e is this something you look into/will look into or is this a set design? Reason for question is that it gives quite a bit of extra peak power(we measured around 250mW extra) compared to ordinary chirp peak power.

Thanks,

/ Wolfgang

0 Wolfgang Wendler TI 9 months ago in reply to Wolfgang Wendler TI

TI__Intellectual 2310 points

Hi Blake,

Customer asked if we have any feedback on their comment/question from 2 weeks ago?

Thanks,

/ Wolfgang

0 Blake Kisshauer 9 months ago in reply to Wolfgang Wendler TI

TI__Expert 4360 points

Wolfgang,

Thanks for checking in, we are still correlating this to internal data and will respond soon.

0 Blake Kisshauer 9 months ago in reply to Blake Kisshauer

TI__Expert 4360 points

Wolfgang,

It looks like you are using less than max TX and RX in your configuration. You are using 2TX and 2RX. In cases where there are less than 2T 3R, we expect the spike will dominate. This is expected and is due to the 1V LDO comming up.

So yes, all is as expected. Thanks for your patience.

Blake

0 Wolfgang Wendler TI 9 months ago in reply to Blake Kisshauer

TI__Intellectual 2310 points

Hi Blake,

Thank you. I have informed my customer.

Best,

/ Wolfgang

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IWRL6432: Current spike at first chirp in frame