I'm trying to reduce power consumption on an MP3 module controlled by an Arduino. The MP3 module specs are:
- 3.2-5V (typical 4.2V)
- <1A peak current, 20mA on standby (which is too much on batteries)
In my prototype, I use a simple diode to lower the 5V regulated from Arduino by around 1V. I also have 1k resistors to adapt logic level on serial communication.
Basically my idea is to use a mosfet as a switch, so that the arduino can enable/disable power supply to the MP3 module, either on high:
Or on low side:
My questions are:
- Are the circuits above correct?
- What are some good options of widely available mosfets? IRL540?
- How do I pick the gate and pulldown resistor values?
- In low-side configuration, do I still need the TX/RX resistors?
- Should I add a ceramic capacitor to eliminate any noise from speakers/sudden change in current, and what sort of value?