ESP32 Restarting

[amintegia]

Hello everyone,

We see that there are problems with our microcontroller, an ESP323-S3, power supply. The module starts correctly from 4.2V to 3.3V. However, when the voltage drops from this value, the microcontroller gives a "brownout" error which indicates that the supply current is not sufficient.

The input voltage goes first through a BOOST (https://www.mouser.es/datasheet/2/277/MP3120-2945726.pdf) to 5V and then through a LDO (https://www.mouser.es/datasheet/2/389/ld1117-1849389.pdf) to 3.3V as you can see in the attached image.

We believe that this problem could be due to the start of some bluetooth process of the microcontroller which requires a higher current peak than normal. Although in principle this should not create any problem since both the BOOST and the LDO are capable of supplying values above 300 mA.

[Shonky]

Is that the real schematic used to create a PCB design? There are a number issues with it as drawn.

What is ESP_BUS supplied from?

Got a scope? Put the supply rail on the scope.

[Doctorandus_P]

Those radios can be very power hungry. If you do a search for peak current for ESP32, then you find suggestions that it may be over 700mA. So I suggest you start by actually measuring what your peak currents are.

[amintegia]

Hi Shonky, thanks for your reply.

This is just a small part of a series of schematic sheets. ESP_BUS is powered from a USB connection, passed through the MP3120 and regulated by the LDO.

Secondly, we have already measured the voltages on the ESP32 power pin. We saw 3.3 V are regulated correctly over a 4 ms time period from 0 V.

[amintegia]

Those radios can be very power hungry. If you do a search for peak current for ESP32, then you find suggestions that it may be over 700mA. So I suggest you start by actually measuring what your peak currents are.

Hello Doctorandus, thank you for your answer.

Probably that is the origin of the problem, we will try to measure that current and I will comment you the results.