ESP32 reduce peak consumption during BLE init

Hr.Mitrev
Posts: 4
Joined: Tue Sep 04, 2018 2:31 pm

ESP32 reduce peak consumption during BLE init

Postby Hr.Mitrev » Tue Jul 20, 2021 9:01 am

Hi!
I have developed esp32 board myself with www.diodes.com/assets/Datasheets/AP2138-9.pdf LDO. It was not intended to be used with bluetooth and the quiescent current had to be tiny. Unfortunatelly down the line I had to include BLE functionality. Now the problem is that during initialization of ble there's a peak consumption of about 190mA for 20ms. The LDO's datasheet states that with consumption of 100mA it has dropout of 700 to 1000mV and if the consumtion is 250mA, the dropout is 1000-1300mV. Since my device is powered by a single Li-Ion cell, the 3V3 rail in some devices sags below 2.4V and brownout is triggered. The battery should not discharge to minumum voltage. At 3.4V the device enters deep sleep. I use nimble libraries for my bluetooth functionality.

So my question is if there's a way to reduce the peak consumption(190mA for 20ms) of the bluetooth periph during init. This will solve my problem without requiring hardware changes which at this point will be quite inconvinient. I am reducing tx power to ESP_PWR_LVL_N12. Unfortunately it does not help. Maybe this consumtion is correlated with phy calibration? Also brownout shouldn't be disabled even momentarily.

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