Power consumption

A project log for ESPresso Scale

Fully open source scale with ADS1232 24-bit ADC, ESP32 MCU and some coffee related software features.

jousisjousis 07/08/2019 at 20:330 Comments

Currently in a quest to minimize deep sleep power consumption of the latest revisions (white=4layer, black 2 layer).

I've managed to go as low as 60uA with minor spikes at 70uA with 2 button modules connected (LEDs removed) and one 128x32 OLED.

My main LDO (TLV75533PDBVR) consumes ~25uA when the scale is in deep sleep. I have some HT7833 that can drop the sleep current further but since I cannot find them as easily as the TI ones I will test them when everything else is set in stone.

I could save some more uA if I install a switch (mosfet) for the ADC instead of keeping it in sleep mode, but it wouldn't worth the cost and complexity. The analog +3.3V supply for the analog pins and the load cell is controlled by the secondary LDO (0.01uA sleep current).

For this amateur design around ESP32 WROOM module, I am happy even with 100uA. With a proper lipo (1300mAh) it can last more than a year in stand by (but of course it won't because...real life :D ).

Will update the gitlab repo with the firmware fixes and the latest revisions after all the tests. As usual, if you are in a hurry, feel free to contact me.