Rotation angle detection device and electric power steering device including same rotation angle detection device

A rotation angle detection device, comprising:

• an intermediate signal generator configured to generate an intermediate signal based on a product of a sine signal and a cosine signal which are based on a rotation angle of a rotating body;
• a first multiplication circuitry configured to multiply the intermediate signal by one of the sine signal or the cosine signal;
• an addition/subtraction circuitry configured to add the other one of the sine signal or the cosine signal and an output of the first multiplication circuitry to each other or to subtract the output of the first multiplication circuitry from the other one of the sine signal or the cosine signal;
• and
• a first rotation angle calculator configured to calculate the rotation angle of the rotating body based on the one of the sine signal or the cosine signal and on an output of the addition/subtraction circuitry.