JP-2026074521-A - Current sensor

JP2026074521AJP 2026074521 AJP2026074521 AJP 2026074521AJP-2026074521-A

Abstract

[Problem] To provide a current sensor that performs a fuse function when an overcurrent flows. [Solution] The current sensor 1 comprises a conductor 40 having first and second terminal portions 41a, 41b for inputting and outputting current, a turn portion 43, first and second body portions 42a, 42b connecting one end and the other end of the turn portion to the first and second terminal portions, respectively, a magnetic sensor 30 disposed on the conductor, and a package that seals the turn portion of the conductor, the first and second body portions, and the magnetic sensor, and exposes the first and second terminal portions. The first and second body portions include parallel sections 44a, 44b provided with at least one void, and the cross-sectional area of a continuous section of the conductor that intersects perpendicularly with the inner contour surface of the conductor is smaller than the cross-sectional area of other continuous sections between the inner contour surface of the conductor outside the parallel section and the outer contour surface of the conductor, which is partitioned between the inner contour surface of the conductor within the parallel section and the inner surface of the void located closest to the inner contour surface of the conductor. [Selection Diagram] Figure 1

Inventors

井上仁人
川崎俊明

Assignees

旭化成エレクトロニクス株式会社

Dates

Publication Date: 20260507
Application Date: 20241021

Claims (20)

A conductor having a first terminal portion for inputting current, which is arranged on one side in the first axial direction; a second terminal portion for outputting current, which is separated from the first terminal portion in the second axial direction intersecting the first axial direction; a turn portion arranged on the other side in the first axial direction relative to the first terminal portion; a first body portion connecting one end of the turn portion to the first terminal portion; and a second body portion separated from the first body portion in the second axial direction, which connects the other end of the turn portion to the second terminal portion. A magnetic sensor disposed on or near the conductor, The package comprises the turn portion of the conductor, the first body portion, the second body portion, and the magnetic sensor, and the first terminal portion and the second terminal portion, At least one of the first fuselage section and the second fuselage section includes a parallel section having at least one void, Viewed from a third direction intersecting the first and second axial directions, the cross-sectional area of a first continuous cross-section of the conductor that intersects perpendicularly with the inner contour surface of the conductor, and is defined between the inner contour surface of the conductor within the parallel section and the inner surface of the at least one void located closest to the inner contour surface of the conductor, is smaller than the cross-sectional area of the other continuous cross-section between the inner contour surface of the conductor outside the parallel section and the outer contour surface of the conductor. Current sensor.
Viewed from the third direction, a second continuous cross-section exists that intersects perpendicularly with the inner contour surface of the conductor outside the parallel section, and within a continuous cross-section between the inner contour surface of the conductor and the outer contour surface of the conductor, lies on a plane that intersects perpendicularly with the inner contour surface of the conductor between the inner contour surface of the conductor and the outer contour surface of the conductor within the parallel section, and has a cross-sectional area smaller than the sum of the cross-sectional areas of the multiple cross-sections demarcated by the inner contour surface, the inner surface of the at least one void, and the outer contour surface, as described in claim 1.
The current sensor according to claim 1, wherein at least one of the first and second body portions has a tapered portion that increases the cross-sectional area of the cross-section perpendicular to the inner contour surface of the conductor, extending from the connection portion with the turn portion in the direction from the other side to the one side in the first axial direction.
The first fuselage section has a first connecting portion that connects to the turn section, The second fuselage section has a second connecting section that connects to the turn section, At least one of the first connecting portion and the second connecting portion has a substantially rectangular shape when viewed from the third direction. The current sensor according to claim 1, wherein at least a portion of the magnetic sensor is disposed at at least one of the first connection portion and the second connection portion.
The current sensor according to claim 1, wherein the distance between the contour surfaces of the first and second body portions facing each other is 5 mm or less.
The current sensor according to claim 1, wherein, viewed from the third direction, a continuous cross-section intersects perpendicularly with the inner contour surface of the conductor outside the parallel section, and the cross-section between the inner contour surface of the conductor and the outer contour surface of the conductor has a cross-sectional area greater than the cross-sectional area of each of the multiple cross-sections demarcated between the inner contour surface of the conductor and the outer contour surface within the parallel section by the inner contour surface, the inner surface of the at least one void, and the outer contour surface.
The current sensor according to claim 6, wherein the at least one void includes a plurality of voids arranged so that at least a portion of each void faces the other in the second axial direction.
The current sensor according to claim 1, wherein at least one of the voids has a width of 5 mm or less in the first axial direction.
A substrate disposed on the conductor via an insulating layer, further comprising the substrate supporting the magnetic sensor, The substrate is arranged in at least a portion of the turn portion, the first connection portion, and the second connection portion. The substrate is provided with a thermometer located away from the magnetic sensor. The distances from the parallel section are different for the magnetic sensor and the thermometer. The current sensor according to claim 4.
The current sensor according to claim 9, wherein the substrate is provided with an electronic circuit that independently monitors the temperature using the magnetic sensor and the thermometer, and emits a signal when the temperature difference between the magnetic sensor and the thermometer exceeds a threshold.
A substrate disposed on the conductor via an insulating layer, further comprising the substrate supporting at least two of the magnetic sensors, The substrate is arranged in at least a portion of the turn portion, the first connection portion, and the second connection portion. The distances from the parallel section are different for at least two of the magnetic sensors. The current sensor according to claim 4.
The current sensor according to claim 11, wherein the substrate is provided with an electronic circuit that independently monitors temperature using at least two of the magnetic sensors and emits a signal when the temperature difference between at least two of the magnetic sensors exceeds a threshold.
A substrate disposed on the conductor via an insulating layer, further comprising the substrate supporting the magnetic sensor, The substrate is arranged in at least a portion of the turn portion, the first connection portion, and the second connection portion. When viewed from the third direction, the contour line of the insulating layer is located outside the contour line of the substrate. The current sensor according to claim 4.
The current sensor according to claim 13, wherein the insulating layer includes either an organic layer or a ceramic layer.
The insulating layer comprises polyimide or fluororesin. The current sensor according to claim 14, wherein the contour line of the insulating layer, when viewed from the third direction, is located on the turn portion side when viewed from the parallel section.
The package further comprises a plurality of signal terminals that are separated from the conductor on one side in the first axial direction, with their tips exposed and sealed within the package. At least one of the plurality of signal terminals is closer to the turn section than the other signal terminals. The current sensor according to claim 1.
The current sensor according to claim 16, wherein at least one of the signal terminals is a GND terminal.
The current sensor according to claim 16, wherein, when the current sensor is mounted on a mounting board, at least one signal terminal is connected to a footprint on the mounting board that is larger in area than the footprint on the mounting board to which the other signal terminals among the plurality of signal terminals are connected.
The current sensor according to claim 1, wherein the thickness of the conductor is substantially constant.
A conductor having a first terminal portion for inputting current, which is arranged on one side in the first axial direction; a second terminal portion for outputting current, which is separated from the first terminal portion in the second axial direction intersecting the first axial direction; a turn portion arranged on the other side in the first axial direction relative to the first terminal portion; a first body portion connecting one end of the turn portion to the first terminal portion; and a second body portion separated from the first body portion in the second axial direction, which connects the other end of the turn portion to the second terminal portion. A magnetic sensor disposed on or near the conductor, The package comprises the turn portion of the conductor, the first body portion, the second body portion, and the magnetic sensor, and the first terminal portion and the second terminal portion, At least one of the first fuselage section and the second fuselage section includes a parallel section having at least one void, Viewed from a third direction intersecting the first and second axial directions, Regarding the cross-section of the conductor from the inner contour line to the point where a straight line drawn perpendicular to the contour line first intersects with another contour line of the conductor, the dimensions of the cross-section in the parallel section are smaller than the dimensions of the cross-section in the portion of the conductor outside the parallel section. A cross-section of the conductor obtained by drawing a straight line perpendicular to the inner contour line and extending it to the outer contour line, contains a cross-section in the portion of the conductor outside the parallel section that has dimensions smaller than the sum of the dimensions of the multiple cross-sections in the parallel section. Current sensor.

Description

This invention relates to a current sensor. A current sensor is known in which a conductor through which the current to be measured flows and a magnetoelectric conversion element adjacent to the conductor are sealed within a package, and the amount of current is detected by detecting the strength of the magnetic field generated when the current to be measured flows through the conductor using the magnetoelectric conversion element and converting it into an electrical signal. In such a current sensor, in order to concentrate the magnetic field on the magnetoelectric conversion element and improve detection sensitivity, the cross-sectional area of the conductor portion adjacent to the magnetoelectric conversion element inside the package is made smaller than the cross-sectional area of the conductor portion located at the periphery of the package, thereby increasing the current density in the conductor. As a result, when an instantaneous overcurrent (for example, having a high-frequency component of 1 MHz) flows due to a failure in the system being measured by the current sensor, the conductor inside the package overheats and melts, allowing the current sensor to function as a fuse. Patent Document 1 discloses a pyroelectric circuit breaker that cuts the conductor in response to an overcurrent and prevents further damage by discharging the arc discharge generated at that time to the splitter side. Thus, it is desirable that the current sensor functions as a fuse when an overcurrent flows and does not damage the primary and secondary circuits. [Prior art documents] [Patent Documents] [Patent Document 1] International Publication No. 2017/136221 The internal configuration of the current sensor according to this embodiment is shown in a top view.The schematic configuration of the sensor unit is shown.The definition of rectangularity is shown below.This section defines the shape and size of the conductor for simulation (conductor width and internal region width).The results of the analysis of the density distribution of surge current (1 MHz) flowing through a conductor are shown.This shows the analysis results of the amount of heat generated (average Joule heat) due to surge current flowing through a conductor, relative to the width of the conductor.This section defines the shape and size of the conductor for simulation (conductor width, internal region width, and void location).This shows the analysis results of the amount of heat generated by the current flowing through a conductor (average Joule heat) relative to the location of voids in the conductor.This exhibits surge currents that concentrate and flow inside the conductor due to the proximity effect.This shows the DC current that flows throughout the entire conductor.This shows the fuse operation of the conductor (first phase).This shows the fuse operation of the conductor (second phase).This section defines the shape and size of the conductor for simulation (conductor width, internal region width, void location, and slit width).This shows the analysis results of the amount of heat generated by the current flowing through the conductor (average Joule heat) in relation to the width of the slit in the conductor.The internal structure of a current sensor equipped with a fault detection function is shown in a top view.The arrangement of the conductor, insulating layer, and magnetic sensor is shown in a top view.The configuration of the mounting board with the current sensor mounted on it is shown in a top view.The arrangement of the current sensor and footprint is shown in a top view.The configuration of the current sensor according to the first modified example is shown in a top view.The configuration of the current sensor according to the second modified example is shown in a top view.The configuration of the current sensor according to the third modified example is shown in a top view.The configuration of the current sensor according to the fourth modified example is shown in a top view.The configuration of the current sensor according to the fifth modified example is shown in a top view.The configuration of the current sensor according to the sixth modified example is shown in a top view. The present invention will be described below through embodiments, but these embodiments are not intended to limit the scope of the claims. Furthermore, not all combinations of features described in the embodiments are necessarily essential to the solution of the invention. Figure 1 shows the internal configuration of the current sensor 1 according to this embodiment, viewed from above with the package 10 visible. Here, the vertical direction is defined as the vertical direction, the horizontal direction as the horizontal direction, and the direction intersecting these two directions as the height direction. The current sensor 1 is a sensor that measures the amount of current to be measured by detecting the magnetic field generated around the conductor 40 when the current