US 10,295,578 B2Granted

Current sensor and smart meter

AssigneeKabushiki Kaisha Toshiba

InventorsYoshihiro Higashi, Hideaki Fukuzawa, Tetsuro Wamura, Masakazu Yaginuma, Motomichi Shibano

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Abstract

A full bridge circuit comprises first to fourth magnetic resistance elements. The first and fourth magnetic resistance elements have a first polarity, while the second and third magnetic resistance elements have a second polarity. A comparison circuit compares a first value indicating a difference between a potential of a first connecting node and a first potential and a second value indicating a difference between a potential of a second connecting node and a second potential to determine presence/absence of an external magnetic field. An initial magnetization vector of a magnetization free layer of the first magnetic resistance element is the reverse of that of a magnetization free layer of the second magnetic resistance element. An initial magnetization vector of a magnetization free layer of the third magnetic resistance element is the reverse of that of a magnetization free layer of the fourth magnetic resistance element.

Claims9

Dependent claims

A sensor comprising:

a first magnetic resistance element outputting a first signal;
a second magnetic resistance element outputting a second signal;
a signal outputting circuit outputting a difference between the first signal and the second signal, an output signal of the sensor including an output signal of the signal outputting circuit;
and
an information circuit
outputting a first information if a difference between a first value and a second value is smaller than a threshold value,
outputting a second information if the difference between the first value and the second value is larger than the threshold value,
the first value being a magnitude of an absolute value of a difference between the first signal and a first predetermined magnitude, and
the second value being a magnitude of an absolute value of a difference between the second signal and a second predetermined magnitude,
wherein
the output signal of the signal outputting circuit changes according to a magnetic field in a first direction,
an output information of the information circuit changes according to a magnetic field in a second direction, and
the second direction crosses the first direction.

10 more elements

A sensor comprising:

a first magnetic resistance element outputting a first signal;
a second magnetic resistance element outputting a second signal;
a signal outputting circuit outputting a difference between the first signal and the second signal, an output signal of the sensor including an output signal of the signal outputting circuit;
a first difference outputting circuit outputting a magnitude of an absolute value of a difference between the first signal and a first magnitude;
a second difference outputting circuit outputting a magnitude of an absolute value of a difference between the second signal and a second magnitude;
a third difference outputting circuit outputting a difference between an output signal of the first difference outputting circuit and an output signal of the second difference outputting circuit;
and
an information outputting circuit outputting a first information if an output signal of the third difference outputting circuit is smaller than a threshold value, and, outputting a second information if the output signal of the third difference outputting circuit is larger than the threshold value,
wherein
the output signal of the signal outputting circuit changes according to a magnetic field in a first direction,
an output information of the information outputting circuit changes according to a magnetic field in a second direction, and
the second direction crosses the first direction.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/933,642Filed 5 Nov 2015
Priority: JP 2014-2262936 Nov 2014
Published: US 2016/0131687 A112 May 2016
Granted: 21 May 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification3 codes

G01R 21/08
Arrangements for measuring electric power or power factor: by using galvanomagnetic-effect devices, e.g. Hall-effect devices
G01R 15/205
Using galvano-magnetic devices, e.g. Hall-effect devices , i.e. measuring a magnetic field via the interaction between a current and a magnetic…:…
G01R
Measuring electric variables