I'm creating a low-power IoT sensor node and I wanted to place some LEDs on my PCB. The chosen LED has a forward current of 2mA, which my MCU can easily supply, however I was wondering, as saving power is important, would it be more efficient to connect the MCU to the gate of a MOSFET and power the LED directly off the battery? (please refer to attached image).
I'm not sure if it'd be more efficient to power the LED straight from the MCU or to control it via an MOSFET.
I am aware typically MOSFETS are useful with LEDs that draw a current higher than an MCU can supply but I wasn't sure if this might be something else I'm unaware of.