Current sensing apparatus in power factor correction circuits and related methods are disclosed. An example power factor correction circuit includes a first Gallium Nitride (GaN) transistor having a first current terminal and a second current terminal, a second GaN transistor having a third current terminal and a fourth current terminal, a first diode having a first anode, a second diode having a second anode, the second anode coupled to the first anode, and a resistor having a first terminal and a second terminal, the first terminal coupled to the second current terminal and the fourth current terminal, the second terminal coupled to the first anode and the second anode.