The block diagram shown here is of two brushless DC motors, one with a discrete drive stage and one with an integrated drive stage. The top motor is driven by a high voltage / high current drive stage while the bottom motor is driven by a mid voltage / mid current drive stage. High voltage / high current drive stages are almost always composed of discrete gate drivers and FETs or a module that is composed of discrete gate drivers and FETs.  Mid voltage / mid current drive stages can also be discrete, but are more commonly based on integrated motor drivers. Control, torque, position, and speed feedback loops can be found in all motor types. These control loops consist of optical or electromagnetic sensors, current sense amps, and ADCs. Isolation is primarily needed in high voltage motors for safety. The high voltage plane is typically isolated from the control circuitry and from the user interface.