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2026-04-08 12:42 pm
so recently i am working on project that require a battery powered operation , i am using esp32s3 controller with arduino ide . my application requires a quick wake up from sleep within 1-2 ms duration so i cant use the deep sleep ( it take more 100 ms to wake up ) . so as per datasheet the current consumption in light sleep mode is 250uA now here the thing in my custom pcb when i put esp32s3 in light sleep it shows current consumption around 2 mA . now to verify that nothing wrong in the pcb just for testing i put the esp into deep sleep it shows current around 10uA , so the pcb does not have any leakage current - now real problem is that i would i reduce the 2mA current i the light sleep mode?
2026-04-09 9:35 pm
So long for some kind of reply. I copy pasted your post into chatGPT and received an immediate comprehensive reply.
There is so much more complexity in these new boards and so many variants it appears to be difficult to find the information you need to use them. Takes all the fun out it for a time poor hobbyist like myself compared with the first Arduino boards for which there were lots of books on how to use them and even had a starter book with the board kit itself.
I see @guyzly hasn't received anything either.
2026-04-12 2:14 pm
Hi @kd_lmit,
Sorry I don't have any instant answers, but a quick Google brought up an old discussion, suggesting that your experience is not the first.
https://esp32.com/viewtopic.php?t=41048
which opens with
Hi, I'm looking into my custom board's light sleep current consumption. I'm expecting well below sub-1mA, given ESP32-S3 240 uA light sleep current (claimed on the datasheet) + quiescent current draw from components on-board which I estimate to just be a few hundred uA.
and after showing current graphs, summarises with
There is a ~700 uA dip for ~100 ms+ (which is what I expect light sleep current to be around), then the current consumption goes to ~1.90 mA. Is this normal?
The discussion continues, and I quickly note that the flash memory is implicated ... I'll leave you to read it properly.
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I also noted the ESP-IDF guide is rather lengthy on the subject of sleep modes, indicating a good deal of complexity and options regarding the 'lighter' sleep modes.
https://docs.espressif.com/projects/esp-idf/en/stable/esp32s3/api-reference/system/sleep_modes.html
I haven't read it thoroughly, but my first impression is that 'light sleep' is not a single on/off switch option, but rather a list of different parts of the chip which may be enabled/disabled. Maybe you still have some part that can be disabled, such as flash memory?
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Although my personal direct experience is limited, my impression is that sleep modes for microcontrollers in general, seems to have been an area of difficulty and disappointment over many years, often appearing in the 'bugs' reports for failing to live up to intuitive expectations.
For many people starting with development boards, it is often mixed in with power consumption of other components, such as USB interfaces and voltage regulators, not forgetting pull ups etc., but noting this is a custom PCB design, I assume that this is not relevant in your case.
So sorry, this sounds rather negative, but it seems you could check you have the most appropriate form of 'light' sleep, but if that fails, maybe the ESP32-S3 is not the best chip for the job.
Good luck. Please report your findings of any further investigation, as the ESP32-S3 is a popular, low cost, useful chip in many cases, and you will not be the last one to consider using it in 'light sleep' mode to extend battery life.
Best wishes, Dave