Tool/software:
I am using the audio amplifier LM48100Q which has:
- a permanent 3.3V supply for the IC2VDD pin
- because the MCU I2C is at 3.3V level
- a switched 5V supply for the VDD pin
- it can be turned off to save battery power
However, the audio amplifier is powered and works even when the switched 5V supply to the VDD pin is disabled.
I assume its using the 3.3V on the IC2VDD pin to power the device ?
Is this correct ?
I would have thought the IC2VDD was only for the I2C interface, I am surprised it also powers the device ?
It also means turning the switched 5V supply off will not save battery power, because it will just use the permanent 3.3V supply.
The LM48100Q is a development board from Mikroe....
https://www.mikroe.com/audioamp-click
The schematic is below for reference.
Note: Originally the I2CVDD (pin 4) and the I2C pull up resistors were connected to VDD. I modified the board so I could connect I2CVDD and IC2 pull up resistors to 3.3V....
