I want to realise a basic ESP32 board to control three fans connected in parallel. In order to control the fan power, I'm using the FQP30N06L, a logic-level N-channel MOSFET. As you can see in the simplified schematic below, the MOSFET gate is connected to an ESP32 GPIO pin.
Everything works, but I noticed that the fans don't spin so fast. To debug the issue I measured the total current consumption and it is around 0.7 A.
Theoretically each fan draws 0.2A of current and is powered by 5 V, so a total current consumption of 0.6A should be normal, but if I connect the fans directly to the ground pin of the ESP32 (bypassing the MOSFET), the total current drawn is about 1A.
Of course with 1A of current drawn, the fans spin faster than the previous configuration.
The ESP32 board is USB powered and is configured to draw a maximum of 3 A at 5 V from the power source.
Does anyone know the reason why the current consumption is limited to 0.7 A when I'm using the MOSFET?