SparkFun Forums

[fluflux]

Hi,

The ESP32 has a deep sleep mode that allows it to use less than 2.5 µA, which is a main reason for me choosing it.
I bought the SparkFun ESP32 thing, and on the product page at https://www.sparkfun.com/products/13907 there's also noted that indeed, "2.5 µA deep sleep current", is supported on this board.

However, in practice the power usage I get is 2mA rather than 2.5 µA. What I did was:

1. Disconnect the power led (which of course consumes power)
2. Created a program for that calls " esp_deep_sleep(5000000); " (deep sleep for 5 seconds). No outputs or anything else is activated (no leds on of course).
3. Supplied power (3.3V) to the GND/UBAT connections, I tried as well to the GND/3.3V directly (to bypass any regulator) but same result.
4. Measured the power when in deep sleep mode, I get to 1.9 to 2 mA, consistently. That's about a thousand times too high

Can you please help me to reach the "real" low power consumption? Thx a lot, I'm really hoping for this feature as it was a key decision point to go for the ESP32 Thing. Thx!

[fluflux]

Nobody has any info?
What's the best way to contact sparkfun directly then? As in, I'm a customer and I'd like to reach out to sparkfun because the product is not functioning as it was sold to me ?

[darrellg]

https://www.sparkfun.com/technical_assistance

[anon]

Any updates on topic?
I managed to go down to 900µA with ESP32-THING, nowhere near claimed few µA.

[anon]

Ok, quick fix I found, the SPI Flash has no pull-up resistor for CS pin, so it does not go into standby mode when ESP is in deep sleep.
I've put a 100k pull-up resistor and current dropped from 900µA to 75µA with built-in LDO (55µA quiescent current).

[aspz]

anon, how did you find out that adding a resistor between those two points would lower the power usage? Do you think there is any possibility of further reducing current usage while in deep sleep mode? Why do you think you see 75uA rather than the 5uA reported by others such as this guy?

[VacLab]

For reduced power consumption you have to look at the power-led (a) and at
the supply of the flash IC (b)

a) You have to cut the jumper SJ2 on the back side to stop the power-led from running all the time.
--> Then I got around 800 uA in DeepSleep.

In deep sleep the !CS of the SPI flash in not set by the microcontroller any more, so it is floating.
Mine is floating near ground, so the IC means it is selected. If Vdd of the Flash keeps connected,
it can be activated when DeepSleep starts because !CS in no more set to 3,3V.

b) You have to cut the jumper SJ3 on the back side from 3V3 and connect it with the other pin (FLASH_VDD)
I have not checked who runs that FLASH_VDD pin high and low, but it works with Arduino IDE.
--> Then I got around 65uA in DeepSleep.

@aspz: the guy in the video has no ESP32 thing Board, so many parts (e.G. voltage regulators) are not the same.
So you cannot compare the power consumption directly.

[noblerabbit]

Hi,

Thanks for this post.

I have cut the SJ1 and SJ3 jumpers as you wrote and my current is at 470 uA in deep sleep.
My current in deep sleep: 2.5 mA (with power led on), 1.2 mA (with power led off), 470 uA (with power led off and FLASH_VDD).

Any advice on how to reduce it further?

Thanks.

[rtek1000]

Hi,

Getting some uA consumption is good

But if it is possible to use an RTC (DS3231) with alarm,

It may be possible to completely stop the consumption,

As the RTC has its own battery,

The interrupt pin can perform a reset or initialize a power circuit,

In this way, any circuit could have its consumption totally interrupted, even if it is not with esp32.