2020-07-02 12:02 PM
Hello,
I'm developing a battery-powered application for the STM32WB55 (specifically the STM32WB55RGV6) and am seeing periodic pulses or spikes in the SoC's current consumption every 200ms in STOP2 and standby modes. These pulses occur with the Nucleo board MB1355-C02 as well, though the pulses have a different shape on the Nucleo board than the ones I can observe on the board I designed. I have tried the demo firmware in addition to my own, and observe the pulses with it as well.
A couple other notes:
I've attached couple images from my power analyzer that show the pulse period and shape.
Any help or advice would be very appreciated! Thanks and take care,
Ryan
2020-07-07 01:38 PM
Any thoughts, folks?
2020-07-08 02:00 AM
Is that on a part with SMPS? Probably when sleeping, SMPS is in pulse skipping mode. When VFBSMPS has dropped some margin, C2 from Figure 4 "Pwer distribution " is recharged. Higher temperature -> Higher leakage -> more frequent recharge
2020-07-09 08:55 AM
Thanks for your reply, and a very interesting theory! The part does have a SMPS, but in the STOP2 and standby modes, the SMPS is open and the LDO is powering the low-voltage core. I checked the switching node for the SMPS (called V_LXSMPS on this part) with my scope and saw no switching there.
2024-05-08 07:42 PM
Hi Ryan,
Have you solved this problem?
Regards
Aaron