I'm trying to make a BLE beacon with Li-Ion battery and Qi wireless charging circuit. NRF52833 works in high-voltage mode (VDDH connected directly to the battery, internal LDO regulates VDD) There are a lot of problems with different charging ICs, so had to choose BQ25101Y chip which doesn't have battery over-discharge protection. My plan was to put NRF52833 into shutdown mode with sys_poweroff() when battery voltage is lower than 3.0V. But i've encountered weird problem.
When i call sys_poweroff() function in zephyr application at input battery voltage 3.7..4.2V, power consumption (measured with PPK2) is 0.6uA. But if i decrease input voltage below 3.6V - power consumption jumps to around 45uA at 3.5V (25uA at 2.1V). It doesn't change if i change REGOUT1 at all (stays same for internal LDO output at 1.8V or 3.3V).
This behaviour not unacceptable as in real device battery will have quite small capacity (20-50 mAh) and that consumption will over-discharge battery very fast. This is normal in high-voltage mode or i've screwed something? Below is full schematics for my beacon:
