WiFi power spikes

kostyan5
Posts: 50
Joined: Mon Mar 06, 2017 3:16 pm

WiFi power spikes

Postby kostyan5 » Mon Aug 21, 2017 8:56 pm

We have a custom ESP32 board and we're seeing periodic current spikes (thin blue lines on attached image) to about 400mA. This seems to be related to WiFi operation as it doesn't happen if WiFi is off. They are very short so we suspect it's just an artifact of WiFi radio turning on. Has anyone experienced this before?
DS2_201781911591.png
DS2_201781911591.png (60.39 KiB) Viewed 8078 times

ESP_Sprite
Posts: 8921
Joined: Thu Nov 26, 2015 4:08 am

Re: WiFi power spikes

Postby ESP_Sprite » Tue Aug 22, 2017 12:54 am

Yes, this is most likely the WiFi calibration, which is known to generate a spike like that. It's the reason we advise people to use at least a 500mA-capable power supply in the hardware design guidelines.

WiFive
Posts: 3529
Joined: Tue Dec 01, 2015 7:35 am

Re: WiFi power spikes

Postby WiFive » Tue Aug 22, 2017 4:07 am

ESP_Sprite wrote:Yes, this is most likely the WiFi calibration, which is known to generate a spike like that. It's the reason we advise people to use at least a 500mA-capable power supply in the hardware design guidelines.
Would be great though if rf self test was well documented.

ESP_Sprite
Posts: 8921
Joined: Thu Nov 26, 2015 4:08 am

Re: WiFi power spikes

Postby ESP_Sprite » Tue Aug 22, 2017 4:25 am

Fyi, just talked to a colleague: I may have recognized the spike wrongly; it's more likely to be a WiFi Tx spike.

ESP_Angus
Posts: 2344
Joined: Sun May 08, 2016 4:11 am

Re: WiFi power spikes

Postby ESP_Angus » Tue Aug 22, 2017 4:28 am

How much (low ESR) capacitance do you have on the VCC rail? You should be able to smooth these TX current spikes quite a bit via capacitance.

Who is online

Users browsing this forum: No registered users and 58 guests