JPS61164278A - Temperature compensation for semiconductor magnetic conversion element - Google Patents

Abstract

PURPOSE:To hold always the temperature of a semiconductor magnetic conver sion element constantly using a simple hall effect device by a method wherein the temperature dependence of residual voltage of the semiconductor element and the temperature dependence of the hall coefficient thereof are compensated by detecting the change of positive electrical resistivity of the resistor on the constraining side and the hall effect device is compensated. CONSTITUTION:A constant current I is conducted to a hall effect semiconductor element 2 from a constant-current circuit 1. The semiconductor element 2 is made to increase its resistivity as well with a temperature rise. The potential e0 of the semiconductor element is made to increase so much as a component of voltage DELTAe0 for a constant-current drive. A residual voltage temperature compensation circuit group 9 makes a component of the increased voltage DELTAe0 connect to an adder 6 through an integration circuit 4 and a reference circuit 4a and the output electromotive voltage of the semiconductor element 2 is connected to the adder 6 through an impedence converter 5. By this way, the temperature dependence only of the residual voltage of the hall effect semi conductor element 2 is compensated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to residual voltage temperature compensation and Hall coefficient temperature compensation of a semiconductor magnetic transducer element. Measuring the magnetic quantity of a low magnetic field using a semiconductor magnetic transducer is difficult because it is largely dependent on temperature changes. Furthermore, there is a method in which the entire semiconductor element is kept at a constant temperature in a constant temperature bath, but the sensor becomes large and measurement is inconvenient.

In this method, the residual voltage temperature dependence and Hall coefficient temperature dependence of a semiconductor element are compensated for by detecting a + (brass) electric resistance change of a control side resistance.

The basic operating principle of this device will be explained.

The Hall electromotive voltage formula of a Hall effect semiconductor device is Vout=
RK I・B/d+V(I・B0) (1) Formula RK: Hall coefficient. I: Excitation current. B: Magnetic flux density.

d: Thickness of element.

The first item of the Hall electromotive voltage is the output voltage with respect to the magnetic flux density B, and the second item is the residual voltage V (I
・B0). Electromotive force RK・I depending on magnetic flux density
・The Hall coefficient RK of B/d is a negative temperature coefficient (Figure 4)
have. Voltage V (I・B0) dependent on residual voltage
has a positive temperature coefficient. The present invention converts the changes due to the two temperature dependencies to the temperature dependence (
By detecting the temperature coefficient of resistance), it simultaneously compensates for the negative temperature coefficient that depends on the magnetic field and the positive temperature coefficient that depends on the residual voltage.

FIG. 1 shows an embodiment of the invention.

A constant current I is applied to the Hall effect semiconductor element (2) from the constant current circuit (1). The resistance of the semiconductor element (2) also increases as the temperature rises. The potential of e0 of the semiconductor element increases by Δe0 due to constant current driving.

The residual voltage temperature compensation circuit group (9) converts the increased voltage Δe0 into an adder (6) using an integrating circuit (4) and a reference circuit (4a).
The output electromotive voltage of the semiconductor element (2) is connected to an adder (6) via an impedance converter (5).

e2=RK・I・B/d+V(I・B0) (2) Formula e
3=-V(I·B0) (3) Equation e2+e3=RK·I·B/d (4) Therefore, only the temperature dependence of the residual voltage is compensated.

Similarly to the residual voltage compensation circuit group, the Hall coefficient RK temperature-dependent compensation circuit group (8) detects the increased voltage Δe0 of e0 of the semiconductor element, and integrates the integrating circuit (3) and the reference circuit (3a).
This is a method for temperature-compensating the Hall coefficient by increasing the amount of decrease in the Hall coefficient RK due to temperature rise using the amplifier circuit (7) and the variable gain element (7a).

[Brief explanation of drawings]

Fig. 1 shows an embodiment of the present invention, Fig. 2 shows the residual voltage Vout (1) = V (I・B0) in the absence of a magnetic field, and Fig. 3 shows the output voltage Vout (2) of the semiconductor element in the presence of a magnetic field.
)=RK I B/d+V (I・B0) Figure 4 shows the temperature characteristics of the control side resistance of the semiconductor element and the temperature characteristics of the Hall coefficient RK. Graph (1): Control side resistance graph (2): Hall coefficient

Claims (1)

[Claims] 1. Residual voltage temperature compensation circuit group consisting of a constant current circuit, a reference voltage circuit, an integrating circuit, and an adder that supply a constant current to the semiconductor magnetic transducer; and 2. Hall coefficient compensation of the semiconductor magnetic transducer. A compensation method consisting of a Hall coefficient temperature compensation circuit group consisting of a reference voltage circuit, an integrating circuit and a variable gain circuit.