Patent attributes
A rotation angle measurement apparatus includes: a first Hall element pair for detecting a magnetic component in a first direction; a second Hall element pair for detecting a magnetic component in a second direction different from the first direction; a third Hall element pair for detecting a magnetic component in a third direction different from the first direction and the second direction; and a fourth Hall element pair for detecting a magnetic component in a fourth direction different from the first to third directions. An angle calculation unit calculates a first rotation angle θ of a rotating magnet based upon the strengths of the output signals from the first Hall element pair and the second Hall element pair, and calculates a second rotation angle θc of the rotating magnet based upon the strengths of the output signals from the third Hall element pair and the fourth Hall element pair.