Motor torque control circuit with barking control and motor drive system using the same

A motor control circuit which comprises a reference signal generating circuit for outputting a reference signal for setting a reference rotational speed of the motor;

• a torque control signal generating circuit for outputting a torque control signal in a direction which generates a torque corresponding to the reference signal in response to a rotational speed condition difference represented by a detection signal relating to the rotational speed of the motor and the reference signal and further outputting a torque control signal which generates a torque corresponding to the reference signal when no difference of rotational speed condition is reached;
• and a drive circuit which droves to rotate the motor by supplying a driving current which causes to generate a torque according to the torque control signal, and which further performs a control for stopping the rotation of the motor by driving the motor into the reversing direction when a stop signal for stopping the motor is received, further comprising a level inverting and changing-over circuit disposed between said torque control signal generating circuit and said drive circuit for outputting a torque control signal by inverting the level thereof with reference to the level of the torque control signal which generates the torque corresponding to the reference signal when the stop signal is received and further outputting the torque control signal without inverting the level thereof when no stop signal is received, said reference signal generating circuit includes a clock generating circuit and a driving circuit, and said reference signal generating circuit determines the reference signal as a first reference signal and further generates a second reference signal determined with reference to a lower rotational speed than the reference rotational sped when the stop signal is received by changing the dividing rate of said driving circuit and outputs the same to said torque control signal generating circuit.

A motor control circuit which comprises a reference signal generating circuit which generates a reference signal representing a reference rotational speed of the motor a speed signal generating circuit which generates a rotational speed signal corresponding to a rotational speed of the motor a speed comparing circuit which compares the reference signal and the rotational speed signal and generates a speed difference signal corresponding to the speed difference represented by the reference signal and the rotational speed signal a torque control signal generating circuit which generates a torque control signal which operates to bring back to a torque corresponding to the reference signal in response to the speed difference upon reception of the speed difference signal a drive circuit which drives to rotate the motor by supplying a driving current which causes to generate a torque according to the torque control signal and which further performs a control for stopping the rotation of the motor by generating a torque in the motor into the reversing direction when a stop signal for stopping the motor is received and a level inverting circuit disposed between said torque control signal generating circuit and said drive circuit for inverting the level of the torque control signal with respect to a predetermined reference level, wherein said level inverting circuit outputs a level inverted signal of the torque control signal to said drive circuit when the stop signal is received, and said reference signal generating circuit determines the reference signal as a first reference signal and further outputs a second reference signal determined with reference to a lower rotational speed than the reference rotational speed to said speed comparing circuit when the stop signal is received.

A motor driving system which comprises a motor a reference signal generating circuit which generates a reference signal representing a reference rotational speed of the motor ;

• a speed signal generating circuit which generates a rotational speed signal corresponding to a rotational speed of the motor a speed comparing circuit which compares the reference signal and the rotational speed signal and generates a speed difference signal corresponding to the speed difference represented by the reference signal and the rotational speed signal a torque control signal generating circuit which outputs a torque control signal which operates to bring back to a torque corresponding to the reference signal in response to the speed difference upon reception of the speed difference signal and which further outputs a torque control signal which generates a torque corresponding to the reference signal when the speed difference signal shows no difference ;
• a drive circuit which drives to rotate the motor by supplying a driving current which causes to generate a torque according to the torque control signal and which further performs a control for stopping the rotation of the motor by generating a torque in the motor into the reversing direction when a stop signal for stopping the motor is received;
• and a level inverting circuit disposed between said torque control signal generating circuit and said drive circuit for inverting the level of the torque control signal with respect to a predetermined reference level, wherein said level inverting circuit outputs a level inverted signal of the torque control signal to said drive circuit when the stop signal is received, and said reference signal generating circuit determines the reference signal as a first reference signal and further outputs a second reference signal determined with reference to a lower rotational speed than the reference rotational speed to said speed comparing circuit when the stop signal is received.