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I'm developing an application on ESP32 using the deep-sleep feature to save battery. I read that ESP32 consumes only uA when it works on deep-sleep.

I bought a board from Az-Delivery called D1-R32 with ESP32-WROOM-32 inside.

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I programmed it to enter in deep sleep, and I used some AA batteries to power it. I also powered on my oscilloscope and I used a shunt resistor (1 ohm - 1%) to measure the current flowing from the batteries to the ESP32 board.

The first measure I obtained is about 12 mA. I tried to change the LDO regulator, because the one that the board has is the AMS1117, and that LDO regulator has a quiescent current of 10 mA, so I thought... problem solved?

I replaced the LDO regulator for another one that has 70 uA quiescent current. I powered the ESP32 modules with the batteries, connected the oscilloscope again and now I get 6 mA.

I also tried to disconnect the on state LED. It only dropped to 5.7 mA.

Is there something on this board, that I can modify to achieve a power consumption of uA?

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  • \$\begingroup\$ What components are on the board? \$\endgroup\$
    – HandyHowie
    Commented Jul 27, 2021 at 11:32
  • \$\begingroup\$ How much current does it draw when in active mode? \$\endgroup\$
    – HandyHowie
    Commented Jul 27, 2021 at 11:33
  • \$\begingroup\$ What about the USB-to-Serial converter? \$\endgroup\$
    – StarCat
    Commented Jul 27, 2021 at 11:39
  • \$\begingroup\$ @HandyHowie About 30-40 mA \$\endgroup\$
    – TS.Box
    Commented Jul 27, 2021 at 11:57
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    \$\begingroup\$ Check out this answer with some code for the gpios that reduced sleep from 77uA to 7uA. Also, there is an interesting video from Andreas Spiess testing several ESP32 boads for low power design with a table (link in description) summarizing the result. \$\endgroup\$
    – meuh
    Commented Jul 27, 2021 at 14:10

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