Arduino Soft Latch Power Switch Using the AO4606 MOSFET

by NewsonsElectronics in Circuits > Arduino

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Arduino Soft Latch Power Switch Using the AO4606 MOSFET

IMG20260814063942.jpg

Have you ever wanted your project to use zero current when it’s turned off? This can be achieved by using a soft-latch switch to control the power to your entire electronic project.

The soft latch allows a push of a button to turn the circuit on, powering up the MCU. Once powered, the MCU takes over and holds the power switch on. When you want to turn the project off, the MCU releases the latch, completely disconnecting power from the circuit and reducing the power consumption to essentially zero.

Then, with another push of the button, the soft latch turns the power back on, restarting the MCU and allowing it to take control of the circuit again.


Video that explains how it works https://youtu.be/Inx08JgaJvA

Supplies

Components Required

  1. 1 × AO4606 dual MOSFET IC (N-channel + P-channel)
  2. 1 × 100 kΩ resistor
  3. 1 × Microcontroller (MCU)
  4. 1 × Battery

Build the Circuit

IMG20260814063942.jpg
Schematic.jpg

Connect the two MOSFETs as follows:

N-Channel MOSFET

  1. Pin 1 (S1): Connect to GND.
  2. Pin 2 (G1): Connect to the MCU.
  3. Pin 3 (S2): Connect to VBAT+.
  4. Connect a 100 kΩ resistor between Pins 3 and 4.
  5. Pin 4 (G2): Connect to Pin 7 or Pin 8.
  6. Pin 5: Connect to VOUT.

Push Button

Connect a push button between GND and Pin 4.

When the circuit is powered off, pressing the button pulls Pin 4 to GND, activating the latch circuit and powering the system back on. Once the MCU starts, it can take over and hold the latch on until it is instructed to shut down.


Basic Code

When the circuit is powered on, the MCU’s main job is to output a voltage that keeps the switch latched ON. This can be done in the setup() section of your project’s main code, ensuring that the latch is activated as soon as the MCU starts.


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int LatchPin=2; // use any pin you wish

void setup() {
pinMode(LatchPin, OUTPUT);
digitalWrite(LatchPin, HIGH);
}