Apparatus for controlling rotational speed of motor

An apparatus for controlling a rotational speed of a motor, coupled to a sensing unit capable of outputting a sensing signal, the apparatus comprising:

• an open loop controlling unit, coupled to the sensing unit, for outputting a controlling signal according to the sensing signal and independently of the rotational speed of the motor, wherein the controlling signal is a first controlling signal or a second controlling signal;
• and
• a driving unit, coupled to the controlling unit, for outputting a driving signal to a motor rotor according to the duty ratio of the controlling signal, wherein the driving signal is a first driving signal or a second driving signal;
• the driving unit outputs the first driving signal when receiving the first controlling signal, and outputs the second driving signal when receiving the second controlling signal;
• wherein the motor rotor has a first rotational speed and a second rotational speed, and the motor rotor rotates at the first rotational speed when receiving the first driving signal, and rotates at the second rotational speed when receiving the second driving signal.

An apparatus for controlling a rotational speed of a motor, coupled to a sensing unit capable of outputting a sensing signal, the apparatus comprising:

• an open loop controlling unit, coupled to the sensing unit, for outputting a controlling signal according to the sensing signal and independently of the speed of the motor, wherein the controlling signal is a square wave and has a duty ratio that is determined by the sensing signal;
• a lock protection unit, for outputting a lock protection signal according to whether a motor rotor is locked by external factors, and then determining a lock period;
• a driving timing controlling unit, coupled to the controlling unit and the lock protection unit respectively, for outputting a driving timing signal according to the controlling signal and the lock protection signal;
• and
• a driving unit, coupled to the controlling unit, for outputting a driving signal to the motor rotor according to the driving timing signal.

An apparatus for controlling a rotational speed of a motor, coupled to a sensing unit capable of outputting a sensing signal, the apparatus comprising:

• an open loop controlling unit, coupled to the sensing unit, for outputting a controlling signal according to the sensing signal and independently of the rotational speed of the motor, wherein the controlling signal is a first controlling signal or a second controlling signal;
• a lock protection unit, for outputting a lock protection signal according to whether a motor rotor is locked by external factors, and then determining a lock period;
• a driving timing controlling unit, coupled to the controlling unit and the lock protection unit respectively, for outputting a driving timing signal according to the controlling signal and the lock protection signal, wherein the driving timing signal is a first driving timing signal or a second driving timing signal;
• and
• a driving unit, coupled to the controlling unit, for outputting a driving signal to the motor rotor according to the driving timing signal, wherein the driving signal is a first driving signal or a second driving signal;
• the driving unit outputting the first driving signal when receiving the first driving timing signal, and outputting second driving signal when receiving the second driving timing signal;
• wherein the motor rotor has a first rotational speed and a second rotational speed, and the motor rotor rotates at the first rotational speed when receiving the first driving signal, and rotates at the second rotational speed when receiving the second driving signal.