JP2000046878A - Watthour meter using hall element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out an accurate temperature compensation in a wide range of temperature regions simply inexpensively by constituting a Hall element and a resistor for the temperature compensation to the element of a GaAs crystal. SOLUTION: Two elements A, B of the same crossed shape are formed on a GaAs substrate crystal 7. One is used as a Hall element 1 for measurement and the other is used as a resistor 3 for temperature compensation. For example, a control current is applied to a lateral terminal of one crossed element A and an output voltage is extracted from a longitudinal terminal, and moreover a temperature compensation circuit is connected to a lateral or longitudinal terminal of the other crossed element B. In this case, since the Hall element 1 and resistor 3 are proximate and therefore thermally bond well, an accurate temperature compensation is enabled. At the same time, since the Hall element 1 and resistor 3 vary little in characteristic, a highly reliable temperature compensation is achieved. The Hall element 1 and the resistor 3 can be used separately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a watt hour meter for measuring an amount of electric power by using a magnetic field detection by the Hall effect.
In particular, highly accurate temperature compensation can be performed in a wide temperature range,
The present invention relates to a watt hour meter using a Hall element that can be simply and inexpensively configured.

[0002]

2. Description of the Related Art A watt hour meter using a Hall element converts a voltage and a current to be measured into a control current (drive current) and a magnetic field, and applies the control current (drive current) and a magnetic field to the Hall element, and measures the output voltage of the Hall element. It measures the electric energy of the target. In this watt-hour meter, input / output resistance and product sensitivity change with temperature. For this reason, it is necessary to perform temperature compensation in order to perform highly accurate measurement or measurement over a wide range of temperatures. Various methods have been proposed depending on the driving condition of the Hall element (constant current driving or constant voltage driving), required accuracy, or temperature range.

For example, in the temperature compensation circuits shown in FIGS. 2 and 3, an individual resistor (thermistor) whose resistance varies with temperature is used as the temperature compensation resistor 3 to control the drive current and the amplification factor of the output voltage. In some cases, temperature compensation is performed.
The temperature compensation circuit of FIG.
A voltage V to be measured (a constant voltage in the case of an ammeter) V is applied as a control current (drive current) between the resistors a and 1b via the resistor 2, and the voltage between the voltage output terminals 1 c and 1 d is input to the amplifier 4. At the same time, the current to be measured is not shown, but the conductor through which the current flows is wound or penetrated around the toroidal core, and the Hall element 1 is inserted between the gaps formed in the toroidal core, thereby converting the current into a magnetic field to form a hole. It is applied to the element 1, and a resistor 4 and a temperature compensating resistor 3 in parallel are inserted in series in a feedback resistor circuit of an amplifier 5, and the amplification factor is temperature compensated. The temperature compensation circuit shown in FIG. 3 is a circuit in which a resistor 6 and a resistor 3 for temperature compensation are connected in parallel to a control input terminal 1b of the Hall element 1, and the control current is Is done.

[0004]

Conventionally, there are various types of individual resistors (thermistors) used for temperature compensation, such as those whose resistance increases with temperature (PTC) and those whose resistance decreases with temperature (NTC). Yes, there is convenience that can be selected and used depending on the circuit type. However, there are few resistors whose rate of increase or decrease in temperature with respect to temperature is stable over a wide temperature range, and the circuit configuration becomes complicated to perform accurate temperature compensation over a wide range of temperatures. was there. In addition, such a resistor has a problem that it is expensive as an individual component, and it is difficult to arrange the resistor close to the Hall element with good thermal coupling with the Hall element.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a watt-hour meter using a Hall element which can perform high-accuracy temperature compensation over a wide temperature range and can be configured simply and at low cost. .

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention converts a voltage and a current to be measured into a control current on one side and a magnetic field on the other side and applies the same to a Hall element. In a watt hour meter for measuring a power amount to be measured by an output voltage, the Hall element is formed of a GaAs crystal, and a resistor for temperature compensation of the Hall element is formed of a GaAs crystal.

The Hall element and the resistor are connected to the same G
It may be formed on an aAs substrate crystal.

[0008] The Hall element and the resistor may be housed in the same package.

[0009] The Hall element, the resistor, and a circuit for controlling the Hall element may be housed in the same package.

The Hall element and the resistor may be formed of a conductive layer having a predetermined thickness and a predetermined sheet resistance formed on a semi-insulating GaAs single crystal.

The Hall element and the resistor may have the same active layer structure.

The current to be measured may be converted into a magnetic field while the control current is kept constant, and the current to be measured may be measured based on the output voltage of the Hall element.

[0013]

An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

The gist of the present invention is that the Hall element is made of GaAs crystal and the resistor for temperature compensation is realized by the specific resistance of GaAs crystal or the sheet resistance of the conductive layer (active layer) formed on the surface of GaAs crystal. Temperature compensation of specific resistance or sheet resistance. By forming the Hall element and the resistor for temperature compensation from the same starting material or by the same process and on the same substrate, the Hall element and the resistor have similar temperature characteristics. Accordingly, highly accurate temperature compensation can be performed in a wide temperature range, and a simple and inexpensive wattmeter or ammeter can be provided. It is also a feature of the present invention that the material of the Hall element and the resistor is GaAs. The present invention makes it possible to perform temperature compensation using the temperature characteristics of the resistance value of a resistor made of the same material formed very close to the Hall element, and particularly limits the temperature compensation method and the circuit type. Not something.

The Hall element and the resistor are made of semi-insulating GaAs.
The conductive layer having a thickness of 5 μm or less formed on the single crystal may have a sheet resistance of 200 Ω to 10 kΩ.

FIG. 1 shows a pattern of a module in which a Hall element and a resistor for temperature compensation, which are main parts of a wattmeter or ammeter of the present invention, are formed on the same GaAs substrate crystal. In the pattern of FIG. 1A, two identical cross-shaped elements A and B (both of which can be called Hall elements) are formed on a GaAs substrate crystal 7, and one of these elements A and B is formed. Is used as a Hall element 1 for measurement and the other is used as a resistor 3 for temperature compensation. For example, a control current is applied to a horizontal terminal of one cross-shaped element A to take out an output voltage from a vertical terminal, and a horizontal or vertical terminal of the other cross-shaped element B is set to temperature. Connect the compensation circuit. In the pattern of FIG. 1B, a cross-shaped element A is formed on a GaAs substrate crystal 7.
And a one-letter element C are formed, and the cross-shaped element A is used as the hall element 1 and the one-letter element C is used as the resistor 3. In the pattern of FIG.
A cross-shaped element A and a plurality of single-character elements (shapes and dimensions may or may not be the same) C on an As substrate crystal 7
Are formed, and the cross-shaped element A is used as the Hall element 1. The one-letter element C can be used as the required number of resistors 3 according to the temperature compensation method and the circuit type. In the pattern of FIG. 1D, the GaAs substrate crystal 7
A cross-shaped element A and an arbitrary-shaped element D are formed thereon,
Desired inter-terminal distances and thicknesses are set according to the shape of the element D used as the resistor 3, thereby obtaining a preferable resistance value.

In each of the modules shown in FIG. 1, the Hall element 1 and the resistor 3 are formed close to each other on the same GaAs substrate crystal 5, so that the Hall element 1 and the resistor 3 The mutual thermal coupling is good, and highly accurate temperature compensation is possible. Also, because it can be manufactured in the same process,
Variations in characteristics between the Hall element 1 and the resistor 3 are small,
Highly reliable temperature compensation becomes possible. However, it is not always necessary to form the Hall element 1 and the resistor 3 on the same substrate, and the Hall element and the resistor can be used separately. However, in order to improve the thermal coupling and perform high-precision temperature compensation, it is necessary to integrally package the circuit including the element driving circuit (such as an IC circuit) and to compensate for the entire temperature including the driving circuit. It is preferable to aim.

The GaAs Hall element has a high Hall voltage with respect to the magnetic flux density, has good linearity, and can be used in a wide temperature range. Therefore, the GaAs Hall element is most suitable as the element of the wattmeter or the ammeter of the present invention. More importantly, GaAs
The point is that the rate of change of the crystal with respect to the temperature is almost constant over a wide temperature range in an appropriate specific resistance or sheet resistance range.

FIGS. 4 and 5 show a semi-insulating G by ion implantation.
The temperature characteristics of the input resistance and the temperature characteristics of the product sensitivity of the Hall element formed based on the conductive layer (active layer) formed on the aAs crystal are shown. In the ion implantation, Si ions were accelerated and implanted at 150 kV, and heat treatment was performed to form a conductive layer. The thickness of the conductive layer is about 0.3 μm, and the sheet resistance is about 800Ω. As can be seen from each figure, both the input resistance and the temperature characteristics show very good linearity over a wide temperature range. -40
The input resistance is 0.18% / ° C in the temperature range of 100 ° C to 100 ° C,
The product sensitivity is almost constant with a slope of −0.06% / ° C.

A watt-hour meter was prepared using two Hall elements, one of which was used as a Hall element 1 for magnetic field measurement and the other was used as a resistor 3 for temperature compensation. The temperature compensating circuit is a general circuit shown in FIG. 2. In the prior art, a thermistor was used for the resistor 3 for temperature compensation. However, in the present invention, the input resistance of the Hall element (for temperature compensation) is changed to a resistor. Used as 3. This watt-hour meter can perform extremely high-precision temperature compensation of 1% or less in a wide temperature range of −40 ° C. to 100 ° C. even though a simple temperature compensation circuit is used. there were.

In the watt hour meter of the present invention, if the control current is fixed, the current to be measured is converted into a magnetic field, and the current to be measured is measured by the output voltage of the Hall element 1, the current meter Can be configured.

[0022]

The present invention exhibits the following excellent effects.

(1) Since the Hall element and the resistor can have similar temperature characteristics, highly accurate temperature compensation can be performed in a wide temperature range, and a simple and inexpensive wattmeter or current meter can be provided. Can provide a total.

(2) By forming the Hall element and the resistor in the same process, variations due to the process can be reduced, and highly reliable temperature compensation can be performed.

[Brief description of the drawings]

FIG. 1 is a plan view of a module formed on a GaAs substrate crystal according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a temperature compensation circuit according to the present invention and the prior art.

FIG. 3 is a circuit diagram of a temperature compensation circuit according to the present invention and the prior art.

FIG. 4 is a temperature characteristic diagram of the input resistance of the GaAs Hall element of the present invention.

FIG. 5 is a temperature characteristic diagram of the product sensitivity of the GaAs Hall element of the present invention.

[Explanation of symbols]

 Reference Signs List 1 Hall element 3 Resistor 7 GaAs substrate crystal

Continued on the front page (72) Inventor Ken Takahashi 5-1-1, Hidaka-cho, Hitachi City, Ibaraki Prefecture Inside the Hidaka Plant, Hitachi Cable, Ltd. (72) Inventor Koji Imaizumi 63-24 Sunakubo, Kawagoe-shi, Saitama ( 72) Inventor Masao Kudo 1180 Oocho, Kohoku-ku, Yokohama, Kanagawa Prefecture Room 202, Okurayama Court

Claims (7)

[Claims] 1. A watt hour meter for converting a voltage and a current to be measured into a control current on one side and a magnetic field on the other side and applying the same to a Hall element, and measuring the amount of power to be measured based on the output voltage of the Hall element. A watt-hour meter using a Hall element, wherein the Hall element is formed of a GaAs crystal, and the resistor for temperature compensation of the Hall element is formed of a GaAs crystal. 2. The watt-hour meter using a Hall element according to claim 1, wherein said Hall element and said resistor are formed on the same GaAs substrate crystal. 3. The watt hour meter using a Hall element according to claim 1, wherein the Hall element and the resistor are housed in the same package. 4. The hall element according to claim 1, wherein the hall element, the resistor, and a circuit for controlling the hall element are housed in the same package. Watt hour meter. 5. The semiconductor device according to claim 1, wherein said Hall element and said resistor are formed of a conductive layer having a predetermined thickness and a predetermined sheet resistance formed on a semi-insulating GaAs single crystal. 4. An electricity meter using the Hall element according to any one of 4. 6. The watt hour meter using a Hall element according to claim 1, wherein said Hall element and said resistor have the same active layer structure. 7. The method according to claim 1, wherein the control current is fixed, the current to be measured is converted into a magnetic field, and the current to be measured is measured based on an output voltage of the Hall element.
A watt-hour meter using the Hall element according to any one of the above.