For energy conservation of sensorless two-phase half-wave brushless DC fan, this thesis develops a driver based on analogy circuits with current feedback control and speed feedback control. The main parts of the system include a sensorless start-up circuit, a sensorless commutation detection circuit, a speed feedback control circuit and a current feedback control circuit. Finally, we design experiments to compare it with outside PWM open-loop control and speed feedback control on experiment, the result shows that the driver with both current feedback control and speed feedback control displays better efficiency and lower vibration.