| 摘要 |
The present invention relates to a position detecting device 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 becomes A·K·Bhe1 (A is the amplification factor of a preamplifier, K is a constant, and Bhe1 is the magnetic flux density the Hall element receives), then a PI regulator 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 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.
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