JPH04148868A - Current signal detection device - Google Patents

Abstract

PURPOSE:To enable current signal detection result to be output by amplifying an output signal of a magnetic sensor with an amplification circuit and by comparing the output voltage of this circuit with a reference voltage of with a single comparator. CONSTITUTION:A magnetic sensor 4 is packaged on an upper part of a circuit substrate 5 being in contact with a gap 2 of a core 1 in left and right directions on a paper surface in Figs. (A) and (B) and in a positional relationship for detecting magnetic flux constituents in vertical direction in (C). When current to be detected flows to a coil 3, magnetic flux which is nearly proportional to the current to be detected passes between the gaps 2 of the core. Leakage magnetic flux from the cap of the core passes through the magnetic sensor 4 at a constant ratio so that the magnetic sensor 4 detects magnetic flux density which is nearly proportional to the current to be detected. Therefore, by connecting a proper circuit to the magnetic sensor 4, current signal flowing to the coil 3 can be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION (A field of industrial application)
This invention relates to a current signal detection device that detects an X (state).

(bl) Conventional technology A current signal detection device that detects a current signal in an insulated state from the current path to be detected is designed to obtain a predetermined dielectric strength voltage from the current path to be detected, or to influence the current path from the current signal detection unit to the current path to be detected. For example, it is used in circuits that detect hook signals in devices connected to telephone lines, such as telephones and facsimiles.

The conventional current signal detection device described above is composed of a coil through which the signal to be detected flows, a gas core that concentrates the magnetic flux generated by this coil, and a magnetic sensor that detects the magnetic flux passing between the gaps. ing.

FIG. 5 is a characteristic diagram of a ball element used in a conventional current signal detection device. In the same figure, the horizontal axis is the magnetic sensor.
The vertical axis is the output voltage. Since the ball element is an element that utilizes the pole effect, the polarity of the output voltage changes depending on the direction of the applied magnetic flux.

FIG. 4 is a circuit diagram of a conventional current signal detection device using the above-mentioned ball element as a magnetic center. In the figure, 3 is a coil to which, for example, a telephone line is connected and a current signal to be detected flows;
4 is a magnetic sensor that detects the magnetic flux density generated by the coil 3; 8 is an amplifier circuit that amplifies the output voltage of the magnetic sensor 4;
11 and 12 respectively set the output voltage of the amplifier circuit 8 to +V.
A comparator that compares REF and -VIIEF based on the lightning voltage, and 13 is the two comparator 1
This is an OR circuit that takes the logical sum of the output states of 1 and 12.

In this figure, the core that concentrates the magnetic flux generated by the coil is omitted. Because the circuit is configured in this way, it detects the magnetic flux density that is approximately proportional to the current flowing through the magnetic sensor coil 3, and generates a voltage that is approximately proportional to the magnetic flux density as shown in Figure 5. arise. The amplifier circuit 8 amplifies the voltage to a constant magnification. Comparator 11 is amplifier circuit 8
“H” when the output voltage is higher than the reference voltage (+VR[F)
It outputs the level, and when it is less than the reference voltage, it outputs the voltage. On the other hand, the comparator 12 outputs an "L" level when the output voltage of the amplifier circuit 8 is above the reference voltage (-VREF), and outputs an "H" level when it is less than the reference voltage. Therefore, when the magnetic flux density given to the magnetic sensor 94 is in the hunting region shown in FIG.
The output of the circuit 13 is at the "■)" level, and in other cases is at the "L" level. In this way, coil 3
Even if the connection polarity of the telephone line connected to the coil 3 is undefined and the direction of the detected current flowing through the coil 3 is undefined, whether or not its absolute value exceeds the threshold is converted into a logic signal. can do.

(C1 Problem to be Solved by the Invention) However, as shown in FIG. 4, in the conventional current signal detection device, at least two comparators 11
, 12 and 2 to be given to both comparators.
It requires a circuit to generate one reference voltage and an OR circuit to OR the output levels of both comparators, making the overall circuit configuration complex and requiring a large number of components to be mounted on the board, resulting in miniaturization. This was difficult and costly.

An object of the present invention is to solve the above-mentioned conventional problems and provide a small, low-cost current signal detection device.

f, J1 Means for Solving the Problems The current signal detection device of the present invention is provided with a coil around a core that has a gap in part, through which a current to be detected whose direction is not determined flows, and whose output voltage characteristics with respect to magnetic flux density are A magnetic sensor 9゛ represented by an abbreviated curve is provided between the gears of the core or near the gas socket, and an amplifier circuit for amplifying the output signal of the magnetic sensor (〕°) is provided.
The present invention is characterized in that a single converter is provided which compares the output voltage of this amplifier circuit with gf% lightning voltage and outputs a current signal detection result.

(81 action) In the current signal detection device of this invention, as a magnetic sensor,
A device whose output voltage characteristic with respect to magnetic flux density shows a substantially V-shaped curve, such as a ferromagnetic magnetoresistive element, is used. Therefore, regardless of the direction of the magnetic flux density applied to the magnetic sensor, a voltage signal approximately proportional to the absolute value of the magnetic flux density can be obtained. The amplifier circuit generates a voltage signal approximately proportional to the absolute value of the current to be detected by amplifying the output signal of the magnetic sensor by a fixed factor, and the comparator converts the output voltage of the amplifier circuit into a fixed reference voltage. compare. 1. When the output voltage of the amplifier circuit is a positive voltage proportional to the absolute value of the magnetic flux density applied to the magnetic sensor 9, the comparator compares the input signals using a constant positive voltage as a reference voltage. This makes it possible to convert the detected current signal into a logic signal using the reference voltage as a threshold value.

Since the detection result of the current signal can be obtained with a single comparator, only one reference voltage generation circuit is required to supply the comparator, and an OR circuit is not required, which simplifies the circuit configuration and reduces the number of components. The points will also be reduced.

Therefore, it is possible to reduce the size and cost.

(fl Embodiment) FIG. 1 shows a circuit diagram of a current signal detection device according to an embodiment of the present invention, and FIG. 2 shows a characteristic diagram of a magnetic sensor used in the current signal detection device.

As shown in Figure 2, the magnetic sensor ``generates a voltage that is approximately proportional to the absolute value of the magnetic flux density, regardless of the direction of the magnetic flux density,'' so the output voltage characteristic with respect to the magnetic flux density is approximately V-shaped. Represented as a curve. For example, a ferromagnetic magnetoresistive element can be used as a magnetic sensor exhibiting such characteristics.

As shown in FIG. 1, the current signal detection result according to the embodiment of the present invention is obtained by connecting a magnetic sensor 11 with an amplifying circuit 8 that amplifies its output voltage, and applying +V R to the output of the amplifying circuit 8.
A comparator 9 with EF as a reference voltage is connected. As shown in FIG. 2, the output voltage of the magnetic sensor 4 exhibits a nearly square-shaped characteristic with respect to the magnetic flux density. Occurs. The amplifier circuit 8 fixes the output voltage of the magnetic sensor 4. The comparator 9 outputs a high level signal when the output voltage of the amplifier circuit 8 is higher than the reference voltage (V REF ), and outputs a low level signal when it is less than the reference voltage. Therefore, when the magnetic flux density given to the magnetic sensor 4 is in the hatched region shown in Figure 2, a "H" level is output from the output terminal as the current signal detection result, and in other regions, the current signal detection result is ’ outputs “■, ゛, LE”. In addition, the output deficiency of the center width circuit is in Figure 1 is expressed as 'f-
By extracting from a, an analog signal of the absolute value of the current flowing through the coil 3 can be obtained.

As shown above, a current signal detection result can be obtained using a single comparator. Therefore, only a single reference voltage generation circuit is required, and an OR circuit is not required. Moreover, since the reference voltage is single, the presence or absence of a current signal can be detected with the same threshold value regardless of the polarity of the magnetic flux applied to the magnetic sensor.

Next, the structure of the current signal detection device is shown in Figure 3 (Δ) to (C).
Shown below.

(A) is a top view, (B) is a front view, and (C) is a right side view. In the figure, core 1 consists of two roughly U-shaped cores ia and lb, and these two cores ia and lb are short
By joining together, Camp 2 is formed in one place.

6 is a bobbin, in which the cores la and lb are fixed with adhesive or the like. Further, the coil 3 is wound around the bobbin 6 by a predetermined number S. A pair of core placement parts 6a for placing the core 1 are formed at the bottom of the pohine 6, and a terminal 7 is provided on each side of the core placement part 6a.
a to 7r are embedded. The starting and ending ends of the coil 3 are connected to terminals 7a and 7d, respectively, with a single opening.

As shown in FIGS. 31(B) and (C), the core on which the coil is wound and has a gap in
surface mounted on the top of the That is, the terminals 7a to 7f shown in FIG. 2A are soldered to land portions (not shown) formed on the surface of the circuit board 5, respectively. Note that among the six terminals 7a to 7f, 7b,
7c, 7e, and 1f are dummy terminals for mounting, respectively.

Further, the magnetic sensor 4 is surface-mounted on the upper part of the circuit board 5 in proximity to the gear knob 2 of the core 1.

This magnetic sensor 4 is mounted in a positional relationship to detect magnetic flux components in the horizontal direction to the plane of the paper in FIGS. 3(A) and 3(B), and in the direction perpendicular to the plane of the paper in FIG. 3(C).

With the above configuration, when a current to be detected flows through the coil 3, a magnetic flux approximately proportional to the current to be detected passes between the gears 2 of the core. Since the magnetic flux leaking from the core gap passes through the magnetic sensor 4 at a constant rate, the magnetic sensor 4 ultimately detects a magnetic flux density that is approximately proportional to the current to be detected. Follow”
The current signal flowing through the coil 3 can be detected by connecting the circuit shown in FIG.

Note that when winding the coil 3 around the core 1, the coil 3 may be directly wound around the core 1 without using the bobbin 6, and the starting end and the ending end thereof may be directly connected to the circuit board 5. Furthermore, the magnetic sensor 4 may be provided directly between the gears instead of near the core's gas valve.

(G+Effect of the Invention) According to the invention, the circuit configuration is simplified and the number of parts is reduced, which makes it possible to downsize the entire device and reduce the number of parts.Also, the number of parts is reduced. 1.) The axial stability of the entire device is also improved.

[Brief explanation of the drawing]

FIG. 1 shows a current signal detection device according to an embodiment of the present invention.
[]] Figure 2 shows the characteristic [λ1] of the magnetic sensor used in the current signal detection device. FIG. 3 is a diagram showing the structure of the current 13° C. detection device according to the embodiment, in which (A) is a -L view, (I3) is a front view, and (C) is a right side view. FIG. 11 is a circuit diagram of a conventional current signal detection device, and FIG. 5 is a characteristic diagram of a magnetic sensor used in the device. 1-Core, 2-Gear, P, 3-Coil, 4-Magnetic sensor, 5-Circuit board, 6-Bobbin, 8-Amplification circuit, ] Comparator, "o I< circuit.

Claims (1)

[Claims] (1) A coil in which a current to be detected with an undefined direction flows is provided around a core that has a gap in part, and a magnetic sensor whose output voltage characteristic with respect to magnetic flux density is expressed by a substantially V-shaped curve is installed between the gaps in the core. Alternatively, it is provided near the gap, and includes an amplifier circuit that amplifies the output signal of the magnetic sensor, and a single comparator that compares the output voltage of the amplifier circuit with a reference voltage and outputs a current signal detection result. Current signal detection device.