Adafruit ESP32-S2 Feather: I2C powered through pull-ups when

[linux203]

Low Power friendly! In deep sleep mode we can get down to 30uA of current draw from the Lipoly connection. Quiescent current is from the power regulator, ESP32-S2 chip, and Lipoly monitor. Turn off the NeoPixel and external I2C power for the lowest quiescent current draw.

When I2C_POWER_INVERTED is driven HIGH, the Q1 MOSFET turns off. This is supposed to turn off external I2C power.

However, the i2c pull-ups (R3 and R6) are connected to 3.3v not VSENSOR. Since Adafruit STEMMA QT sensors also contain resistors between SDA/SCL and 3v3, the i2c sensors are still powered through the pull-ups.

[linux203]

I pulled out the DMM. While the ESP32-S2 is in deep sleep, the VIN pin on the AHT20 breakout is 2.836v. The SDA and SCL lines are both at 3.147v.

[jasonwoodland]

also interested in the solution for "low power operation" using external qt attached sensors

[adafruit2]

yes this is going to be fixed in next PCB rev - we'll have a fully separate LDO!