I'm working on controlling the supply of an amplifier board with 5V 2.4A power in a manner which tries to eliminate noise from the speaker. I asked a few professors at my university and they said that an optocoupler would be the best way. Since I need a higher amperage, I also need a MOSFET or transistor or some sort.
The following circuit is the result of my research and testing in Livewire. The idea is that this will then be my first custom PCB which we'll etch in the lab and then incorporate into my refurbishing of an old vintage radio.
Q1: IRL520 (or similar) MOSFET
Q2: 4N35 Optocoupler
CN1: Line to 5V 2.4A power supply
CN2: Cables to On/Off switch
CN3: Power line to amplifier, needs at least 5V 2A
CN4: Control lines to 3.3V microcontroller, (Rasp0W or Arduino)
R1: 1k Ohms to make sure the gate isn't triggered unless microcontroller is HIGH
R2: ~250 Ohms to make sure the optocoupler's LED (Vf~=1.5V) only gets 10mA off a 3.3V line.
When I simulate the circuit by:
adding a 5V source at CN1
shorting the terminals in CN2
adding a lamp/led at CN3
adding a 3.3V source at CN4
The circuit remains closed when the microcontroller is LOW, and when it is pulled high, the voltage to the gate of the MOSFET reads 3.3V (wire marked with purple). However, it doesn't indicate that the light bulb at CN3 lights up.
My line of thinking is that Livewire doesn't know that I'm using a logic-level MOSFET, therefore thinks that I need at least 5V to trigger the gate.
Will this circuit be able to deliver 5V 2.4A to the amplifer at CN3? Are the parts adequate or are there better options out there? Thanks!