Rotation angle detecting device
First Claim
1. A rotation angle detecting device comprising:
- a bridge circuit in which while a magnetic field applied to a magnetic detecting element is changed by rotating a magnetic rotation member mounted on a predetermined rotation shaft, said magnetic field change is converted into a voltage change;
a first differential amplifying circuit for amplifying the signal outputted from said bridge circuit;
an AC (alternating current) coupling circuit for removing a DC component from the output signal of said first differential amplifying circuit;
a second differential amplifying circuit for amplifying the signal output from the AC coupling circuit;
a comparing circuit for comparing the signal outputted from said second differential amplifying circuit with a predetermined reference value to thereby output any one of a signal of “
0” and
a signal of “
1”
;
an output circuit for waveform-shaping said signal having “
0”
, or “
1”
outputted from said comparing circuit; and
an initiating circuit including a first transistor, a second transistor, a third transistor, and a differentiating circuit for driving said first to third transistors;
in which both said first transistor and said second transistor are connected to said AC coupling circuit so as to converge the output signal of said AC coupling circuit into a reference voltage immediately after a power supply is turned ON; and
in which said third transistor is connected to said comparing circuit so as to also converge the input signal of said comparing circuit into an AC coupling reference level.
2 Assignments
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Accused Products
Abstract
In a rotation angle detecting device, a circuit scale thereof is reduced and a manufacturing cost thereof is lowered. The rotation angle detecting device is arranged by comprising: a bridge circuit for converting a magnetic field change of an MR element into a voltage change; a 1st differential amplifying circuit for amplifying the signal outputted from the bridge circuit; an AC coupling circuit for removing a DC component from the output signal of the 1st differential amplifying circuit; a 2nd differential amplifying circuit for amplifying the signal output from the AC coupling circuit; a comparing circuit for comparing the signal outputted from the 2nd differential amplifying circuit with a reference value to thereby output any one of a signal of “0” and a signal of “1”; an output circuit for waveform-shaping the signal outputted from the comparing circuit; and an initiating circuit including a 1st to a 3rd transistors, and a differentiating circuit for driving the 1st to 3rd transistors; in which both the 1st and the 2nd transistors are connected to the AC coupling circuit so as to converge the output signal of the AC coupling circuit into a reference voltage immediately after a power supply is turned ON; and in which the 3rd transistor is connected to the comparing circuit so as to also converge the input signal of the comparing circuit into an AC coupling reference level.
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Citations
2 Claims
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1. A rotation angle detecting device comprising:
-
a bridge circuit in which while a magnetic field applied to a magnetic detecting element is changed by rotating a magnetic rotation member mounted on a predetermined rotation shaft, said magnetic field change is converted into a voltage change;
a first differential amplifying circuit for amplifying the signal outputted from said bridge circuit;
an AC (alternating current) coupling circuit for removing a DC component from the output signal of said first differential amplifying circuit;
a second differential amplifying circuit for amplifying the signal output from the AC coupling circuit;
a comparing circuit for comparing the signal outputted from said second differential amplifying circuit with a predetermined reference value to thereby output any one of a signal of “
0” and
a signal of “
1”
;
an output circuit for waveform-shaping said signal having “
0”
, or “
1”
outputted from said comparing circuit; and
an initiating circuit including a first transistor, a second transistor, a third transistor, and a differentiating circuit for driving said first to third transistors;
in which both said first transistor and said second transistor are connected to said AC coupling circuit so as to converge the output signal of said AC coupling circuit into a reference voltage immediately after a power supply is turned ON; and
in which said third transistor is connected to said comparing circuit so as to also converge the input signal of said comparing circuit into an AC coupling reference level.- View Dependent Claims (2)
both a collector of said first transistor and an emitter of said second transistor are connected to an output terminal of said AC coupling circuit;
both an emitter of said first transistor and a collector of said second transistor are connected to a reference voltage unit of said AC coupling circuit;
a collector of said transistor is connected to the output terminal of said comparing circuit; and
said differentiating circuit is constituted by a resistor and a capacitor, and is connected to the bases of said first, second, and third transistors so as to drive said first, second, and third transistors only for a give period of time duration which is determined based upon both the resistance value of said resistor and the capacitance value of said capacitor.
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Specification
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- Resources
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Current AssigneeMitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation), Maytag Corporation (Whirlpool Corporation)
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Original AssigneeMitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
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InventorsYokotani, Masahiro, Shinjo, Izuru, Mishiro, Naohiro
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Primary Examiner(s)HAN, YOUNGHUIE JESSICA
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Application NumberUS09/994,679Time in Patent Office174 DaysField of Search324/207.12, 324/207.15, 324/207.16, 324/207.19, 324/207.25, 324/207.21, 363/140, 363/132, 323/365US Class Current324/207.19CPC Class CodesG01D 5/145 influenced by the relative ...
