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ESP32 Delay circuit for EN pin

Posted: Thu Dec 26, 2024 1:54 pm
by tachin
Hi there,
I have some problems with the power supply (which I can't change) which is quite weak at the first start-up.

ESP32 often resets several times at startup until the power supply stabilises. I have measured that by adding 10k/20uF for EN pin, the ESP32 startup/power demand is delayed by about 100mS, a period long enough for the power supply to be in optimal condition making the ESP32 start up perfect.

I wonder if this solution could be adequate or could it lead to problems in another area of the ESP32 that I am not contemplating as the values I use for the RC delay are ‘out of spec’.

Thanks!

Re: ESP32 Delay circuit for EN pin

Posted: Thu Dec 26, 2024 3:07 pm
by username
you could use a Reset Supervisor for the EN pin. They also come in through hole versions as well.

https://www.digikey.com/en/products/det ... R/14004302

Re: ESP32 Delay circuit for EN pin

Posted: Thu Dec 26, 2024 5:26 pm
by tachin
username wrote:
Thu Dec 26, 2024 3:07 pm
you could use a Reset Supervisor for the EN pin. They also come in through hole versions as well.

https://www.digikey.com/en/products/det ... R/14004302
Thanks for the recommendation, I will take note. Unfortunately I already have the board finished and have no option to add it in this batch, I'm trying to find a solution for a quick fix.

Anyway, I have had a look at the datasheet and it looks more like a brownout detector that the ESP32 already has and quite robust, what I try to do is to delay the load by 100ms so that the regulator has time to stabilise.

Re: ESP32 Delay circuit for EN pin

Posted: Thu Dec 26, 2024 7:46 pm
by GeoffL
The TLV803EF29DBZR is the right solution for what you described.

It with hold the ESP32 in reset for the set time after the power is at the right voltage. If the voltage dopes, the timer starts again.