Rotation detecting apparatus and electric power steering apparatus using the same

An electric power steering apparatus comprising:

• a motor configured to provide assist torque for assisting a driver's operation of a steering wheel;
• and
• the rotation detecting apparatus comprising:
• a sensor comprising a sensor element that outputs a measurement value indicative of rotation of a detection target, and a circuit module, the circuit module comprising:
• a rotational angle calculator configured to calculate, based on the measurement value, rotational angle information indicative of a rotational angle of the detection target, and generate a rotational angle signal including the rotational angle information;
• a rotation number calculator configured to calculate, based on the measurement value, rotation number information indicative of the number of rotations of the detection target, and generate a rotation number signal including the rotation number information;
• and
• an output unit configured to output, as an output signal, a communication frame storing a series of at least the rotational angle signal and the rotation number signal;
• and
• a controller configured to obtain the output signal from the communicator, and calculate, based on the output signal, information associated with the rotation of the detection target,
• wherein the sensor element of the rotation detecting apparatus is configured to output the measurement value indicative of rotation of the motor as the detection target.