This circuit makes use of a NPN to PNP configuration with the output driving the gate of a NMOS.
With this configuration, an external load can be switched with a voltage higher than that of the input to the base of the NPN.
A simple 3V3 output from a MCU would allow control to be exercised. It is worth noting that the NMOS is operating as a low-side switch and care should be taken to ground sensitive devices which require a low impedance ground reference.
The added advantage is that the circuit is quite energy efficient in that no current is drawn (other than leakage current) when the 3V3 input is switched LOW perfect for lower power application.
