Sensorless solutions remove any sensored components from the design, which helps save on BOM costs. Many TI motor drivers can detect the position of the brushless-DC motor without the use of Hall-effect sensors by either measuring back-EMF voltages generated on unconnected windings of the motor driver (Figure 2-7) or internally estimating the back-EMF voltage (Es) generated (Figure 2-8) using winding resistance (R), winding inductance (L), phase current (Is), and motor voltage (Vs).

Sensorless control is typically used for speed applications since the motor generates enough Back-EMF when it is spinning at a constant speed. Position control cannot be sensorless, and torque control is difficult to implement sensorlessly.