POSITION DETECTION DEVICE AND POSITION DETECTION METHOD

摘要

The present invention relates to a position detecting device and position detecting method capable of canceling an error due to looseness in a vertical direction and of eliminating variation in temperature characteristics by calculating a ratio between output voltages of a plurality of Hall elements. Assuming that the Hall voltage Vhe1 of a Hall element (22a) becomes A·K·Bhe1 (A is the amplification factor of a preamplifier (32), K is a constant, and Bhe1 is the magnetic flux density the Hall element receives), then a PI regulator (41) automatically adjusts the bias point of the PI output by feedback control in such a manner that A·K·Bhe1 + Vref = AGND (= 0) holds. The Hall voltage Vhe2 of the Hall element (22b) after amplification becomes A·K·Bhe2. Since K = -Vref/A·Bhe1, the Hall voltage Vhe2 of the Hall element is given by -Vref·Bhe2/Bhe1. It is equivalent to the ratio between the output voltages of the Hall element (22a) and Hall element (22b) because the Hall voltage is proportional to the magnetic flux density.