| 摘要 |
PROBLEM TO BE SOLVED: To actualize a Hall electromotive-force signal detector effectively preventing a settling error in the signal detector for performing detection signal processing by using a ΔΣ modulator. SOLUTION: In detecting a rotation angle, etc. by using Hall electromotive force generated by supplying a bias current to a Hall element 101 in a magnetic field, the direction of the bias current and its signal polarity are changed by a first chopper switch 103 to acquire a modulated Hall electromotive-force signal with the electromotive force modulated thereinto, and this signal is demodulated by a second chopper switch 105 to acquire a demodulated Hall electromotive-force signal. This demodulated Hall electromotive-force signal is ΔΣ-modulated by the ΔΣ modulator 106 to acquire a detection output. Here, timing control is exercised so that a lead time about twice as long as the width of a drive pulse ϕ2 of the ΔΣ modulator 106 is given between the point of changing the direction of the bias current in a switch circuit 104 and the point of holding the demodulated Hall electromotive-force signal supplied to an operational amplifier in the ΔΣ modulator 106. COPYRIGHT: (C)2011,JPO&INPIT
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