CC3235MODSF: WiFi module generates a lot rush current when power up period ，please help me to find solution way, thanks!

Hi Kirin, 

I will test this out in the lab this week, in the meantime;

• Have you verified that the clock is stable when powering up?
• Have you gotten your board's design reviewed? You can request one here. (www.ti.com/.../SIMPLELINK-WIFI-DESIGN-REVIEWs )

Best Regards,

Jessica M. Torres

• Hi Jessica M. Torres,

  Thank you for you reply，my answer as follows；

  • my design is use CC3235MODSF which integrates crystal in package，i can not verified the clock.
  • i will request a board's design today
  • I have do a test on LAUNCHXL-CC3235SF Board, it also found rush current, pls see the attachment,thanks!
  • LAUNCHXL-C3235SF test.docx

Hi,

I am not sure what issue do you see at your power consumption. CC32xx devices are radio devices and you should expect hight current spikes when radio is at TX. When is CC32xx device is starting (NWP is enabled) there you can expect peak calibration current (~450mA at 3.3V).

But maybe I did not understand properly what you want to say.

Jan

Hi Jan， 

Thanks for your reply!

When CC3235MODSF start to power up and nRESET pin hold high, after about 1.2s later，there will appeare 3 times rush current (max 600mA )in 2.7s，maybe the module is doing calibration, So calibration event will be trige by a reset?

Hi,

This depends on calibration mode. Please read SWRU455 at chapter 4.9. Current spike 600mA is slightly higher that can be expected during calibration at 3.3V. But maybe you not have enough of bulk capacitance and maybe your measurement may to be slightly off.

In this document you can find some typical current characteristic in different mode of operation.

Jan

Hi,

From provided information I am not able say what exactly it is. Because behaviour depends on your code.

It may to be spikes during WLAN network scan, connection into WLAN or other WiFi TX activity.

Jan

Hi  Jan

I have capture a waveform with my wifi module, the capture period is from power up  to TX a data. My wifi board is the client, can you help to check the workflow of wifi module ? and i can't confirm  what the moudle is doing at quetion mark in the picture. Thanks!

Hi,

I am not sure what is meaning of current pulses after calibration current. Maybe TI guys can help you with explanation.

• WLAN scan is likely first part of wifi connection.
• Small spikes (marked ??) are probably TX of responses to management frames (beacon frames). This behaviour can be changed by  Power Policy settings.
• Last two spikes are both TX (high peak) and followed by the RX

Jan

Hi 

Thanks again, you really help a lot！

Have  a good day!

Hi Kiryn,

The impulses after calibration should be the device initialization (not “wlan scan”), and then the device starts trying to complete wi-fi connection (around the 2.25s mark from "power up").

As Jan mentioned the spikes marked with "???"  are the beacons. If you configure the device power mode to be LSI, the station will send less beacons and conserve power (see section 15.1.3.1 LSI (Long Sleep Interval) of the SimpleLink Wi-Fi® CC3x20, CC3x3x Network Processor User’s Guide).

The last two impulses being TX and then RX seems correct as well, but it depends on the code used.

Best Regards,

Jessica M. Torres