I am designing a small audio player for my daughter, based on a TTGO T-Display. It will have a few buttons for control and to select playlists. It will have an SD card reader and two MAX98357 amplifiers for stereo sound.
This is a partial picture of it:
Currently, I am putting it to deep sleep, using a switch connected to the GPIO 33 to put it to deep sleep and to wake up from deep sleep. This switch is actually part of a potentiometer with an on/off switch. When the switch is high, the ESP32 goes to deep sleep. When low, it wakes up and stays awake.
But I was wondering, would it be worth to add some sort of PMIC to cut power for the SD Card and the two amplifiers when in deep sleep? While connected to the USB, I see that there's still a consumption of around 0.017A (17mA), which maybe is due the UART on the ESP32. My theory is that if I have the VDD of the SD Card (J3) and of the two MAX98357 cut via a PMIC or any inverter, I could save some battery.
So my questions are:
- Can I add a PMIC that would cut the 3.3V for the mentioned components when it gets a high input, and resume on a low input?
- If so, would this impact the voltage these components receive? I've seen that some people suggested the use of a simple inverter circuit with a transistor and resistor to get this, but I wonder if a dedicated PMIC would be a better choice.
- Bonus question: would it actually worth the effort, or will these components already be using very little? On a very short test, I noticed that simply removing them while on deep sleep reduces the consumption from 17mA to 15mA, so not really extraordinary.
