JP2003262665A - Magnetometric sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetometric sensor which can be constituted of one magnetic sensing unit, as compared with a conventional magnetometric sensor needing two magnetic sensing units. <P>SOLUTION: The magnetometric sensor comprises a Hall element 50, made of a semiconductor thin film or a magnetic thin film, and signal-processing circuits (51, 52, 53, 54, R1, R2) for outputting a tertiary digital signal in response to the level of the detection signal. The sensor outputs the tertiary digital signal, in response to the level of the detected magnetic signal at the output terminal. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a magnetic sensor,
In particular, it relates to a magnetic sensor used for detecting a tilt or a rotational position in a tilt switch, a magnetic encoder or the like.

[0002]

2. Description of the Related Art As a magnetic sensor, a Hall IC using a Hall element as a sensor is well known.
C is composed of a magnetic sensor section made of a compound semiconductor such as Si or InSb, and a Si signal processing IC section.

Since the Hall element is an analog output type magnetic sensor, when used as a single Hall element
It can be seen from the output signal whether it is in a T magnetic flux density atmosphere. However, as a magnetic sensor application, it is often desired to know whether or not the magnet is closer than the mT magnetic flux density atmosphere. If the magnetic flux density is 6 mT or more when the magnet approaches, it is very convenient to use a digital output type sensor that outputs Low for magnetic flux density of 6 mT or more and High for magnetic flux density of less than 6 mT. is there. Most of such Hall ICs are configured by a Schmitt trigger circuit that compares the Hall element output with a predetermined threshold value and outputs a digital output as shown in FIG. The output format of the digital output is roughly divided into two types, as shown in FIG. 2, in the case where the magnetic flux density has a hysteresis centered on 0 and in the case where the magnetic flux density has an offset in the center as shown in FIG. Method is used.

[0004]

However, the conventional Hall IC is low and high as shown in FIGS. 2 and 3.
Only the binary digital output type of h exists. The difference between FIG. 2 and FIG. 3 is that the magnetic poles on both sides output High and Low signals (FIG. 2), or the magnetic poles on one side are High and Lo.
This is to output the signal of w (FIG. 3).

Consider, for example, a case where an inclination detecting switch is formed with a structure as shown in the plan view of FIG. In FIG. 4, 1 is a magnetic sensor, 2 is a magnet, 3 is a sensor housing, and 4 is a storage chamber. The magnetic sensor 1 is fixed to the upper surface side or the bottom surface side of the magnet 2. The magnet 2 is movably held in a storage chamber 4 provided in the sensor housing 3. When the sensor housing 3 tilts to the right and the magnet 2 moves to the right, the magnetic flux of the magnetic sensor 1 part becomes the magnetic flux of the N pole. When the sensor housing 3 tilts to the left and the magnet 2 moves to the left, the magnetic flux of the magnetic sensor 1 part becomes the magnetic flux of the S pole. However, the conventional Hall IC cannot detect whether it is tilted to the right, left, or neither. When the conventional Hall IC is used, it is necessary to provide the Hall IC on each of the left and right ends in order to detect whether the Hall IC is tilted left or right.

Therefore, an object of the present invention is to detect the tilt by using only one Hall IC without providing a plurality of Hall ICs when used in the tilt detection switch as shown in FIG. It is to provide a magnetic sensor that can be performed.

[0007]

In order to achieve the above object, in the invention of claim 1, the magnetic detection means comprising a semiconductor thin film or a magnetic thin film, and a detection signal from the magnetic detection means are inputted and the detection is performed. A magnetic sensor having a form including a signal processing circuit that outputs a three-valued digital signal according to a signal level was implemented.

According to a second aspect of the present invention, in the magnetic sensor according to the first aspect, in the signal processing circuit, which of the levels obtained by dividing the output range of the detection signal by the detection signal from the magnetic detection means into three levels? And a voltage generator that generates three different voltages and outputs one of the voltages according to the signal from the level detector. did.

According to a third aspect of the invention, in the magnetic sensor according to the first aspect, the signal processing circuit has a low level when the detection signal is smaller than a first threshold value, and has a high level in other cases. A level discriminating unit that outputs a first signal and a second signal that becomes a low level when the detection signal is larger than a second threshold and becomes a high level in other cases, and a collector and an emitter of each other are connected. The first signal is applied to the bases of the first and second transistors, the collectors of which are coupled to a predetermined DC voltage via a first resistor having a predetermined resistance value. And inputs the second signal to the base of the second transistor whose emitter is coupled to another predetermined DC voltage via a second resistor having a resistance value substantially the same as the predetermined resistance value. Configuration A those, wherein the first transistor and the connection point of the second transistor 3
A magnetic sensor that outputs a digital value signal was implemented.

According to a fourth aspect of the present invention, the magnetic detection means formed of a semiconductor thin film or a magnetic thin film and the detection signal from the magnetic detection means are input, and a binary digital signal of a plurality of bits corresponding to the level of the detection signal is input. A magnetic sensor having an output signal processing circuit was implemented.

By using the magnetic sensor according to the present invention having the above structure, the left and right tilts can be detected by one Hall IC. Even if it is necessary to use two conventional magnetic sensors, it can be configured with one magnetic sensor,
The number of parts of the sensor unit using this magnetic sensor is reduced, and the assemblability is improved. Further, it becomes possible to miniaturize, and it is possible to conveniently cope with various applications.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. (Embodiment) FIG. 5 is a configuration diagram showing a configuration of an embodiment of a Hall IC in the present invention, and FIG. 6 is a characteristic diagram showing an output characteristic of a magnetic sensor of the present invention.

For example, when the magnetic flux density is increased (in absolute value), B _0p 1 or more is Low level, B _0p
High level in a state of less than 2 and Mi in other states
The dd1e level is output. Further, this characteristic has hysteresis, and the output voltage level changes with another threshold value (B _rp 1, B _rp 2) with respect to the decrease of the magnetic flux density.

In FIG. 5, the detection signal from the magnetic sensor section including the Hall element 50 is amplified by the amplifier 51 and input to the level discriminating circuit 52. Level discrimination circuit 5
Reference numeral 2 includes two window comparators, which converts the detection signal into two digital signals corresponding to the detection level, and inputs each signal to the bases of the transistors 53 and 54.

One of the two digital signals (comparator output 1) has a low level when the detection signal is smaller than the first threshold value, and has a high level in the other cases, and the other (comparator output 2) has the detection signal. Is the second threshold (>
When it is larger than the first threshold value), it becomes a low level, and in other cases, it becomes a high level.

Transistors 53, 5 as shown in FIG.
Using an output stage circuit consisting of 4 and two resistors R1 and R2,
From this converted digital signal, convert the three-valued digital signal to V
It is possible to get out. This state is shown in FIG. The values of the resistors R1 and R2 in FIG. 7 need to be substantially the same.

(Other Embodiments) Even if the circuit for outputting the above-mentioned three-valued digital signal shown in one embodiment is not provided, the magnetic sensor output terminals are two terminals and the output of the window comparator is used as it is as the output of the magnetic sensor. It is also possible.

Apart from this, it is also possible to provide a plurality of output terminals instead of the above-mentioned three-value digital output, and to output each as a binary output digital output.

FIG. 9 is a block diagram showing the configuration of another embodiment of the Hall IC according to the present invention. In this embodiment, the level discrimination circuit 90 is provided with two output terminals (Output).
1, Output2) to output a 2-bit binary signal, it is possible to obtain a 4 × 2 digital output of 2 × 2.

The structure of the level discriminating circuit 90 is not particularly limited, and a high-order binary digital signal which is low level when the detection signal is smaller than the first threshold value and is high level in other cases, A low-order bit that becomes low level when the detection signal is smaller than a threshold value smaller than the first threshold value and smaller than a threshold value larger than the first threshold value and larger than the first threshold value, and becomes high level in other cases. It suffices if the configuration outputs the binary digital signal of.
Such a configuration has a reference voltage source,
When using a comparator, a gate, etc., it can be easily configured in various other cases.

The present invention is not limited to the above embodiment, but can be modified in various ways.

[0022]

As described above, according to the magnetic sensor of the present invention, the magnetic signal from one magnetic detecting means is output as a ternary digital signal according to the detection level. According to the magnetic sensor of the fourth aspect of the invention, the magnetic signal from one magnetic detection means is output as a 2-bit binary signal corresponding to the detection level. Even if it is necessary to use a single magnetic sensor, the magnetic sensor can be configured with one magnetic sensor (magnetic detecting means). Therefore, the number of parts of the sensor unit using this magnetic sensor can be reduced, the assembling property can be improved, and the size can be reduced. This is possible, and there is an effect that various applications can be conveniently handled.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a configuration of a conventional Hall IC.

FIG. 2 is a diagram showing an example of an output format of a conventional Hall IC.

FIG. 3 is a diagram showing another example of the output format of the conventional Hall IC.

FIG. 4 is a diagram showing an example of a configuration of a magnetic tilt detection switch.

FIG. 5 is a configuration diagram showing a configuration of an embodiment of a Hall IC in the present invention.

FIG. 6 is a characteristic diagram showing the output characteristic of the magnetic sensor in the embodiment of FIG.

7 is a circuit diagram of an example of an output stage circuit that outputs a three-value digital output in the embodiment of FIG.

8 is an explanatory diagram illustrating that a ternary digital signal is obtained by the output stage circuit of FIG.

FIG. 9 is a configuration diagram showing a configuration of another embodiment of the Hall IC according to the present invention.

[Explanation of symbols]

1 Magnetic sensor 2 magnets 3 sensor housing 4 storage room 50 Hall element 51 amplifier 52,90 Level discrimination circuit 53,54 transistor 59 Regulator

Claims (4)

[Claims] 1. A magnetic detection means comprising a semiconductor thin film or a magnetic thin film, and a signal processing circuit for receiving a detection signal from the magnetic detection means and outputting a ternary digital signal according to the level of the detection signal. A magnetic sensor characterized in that 2. The magnetic sensor according to claim 1, wherein the signal processing circuit determines which level the detection signal from the magnetic detection means is in a level obtained by dividing the output range of the detection signal into three. And a voltage generator that generates three different voltages and outputs one of the voltages according to a signal from the level determiner. 3. The magnetic sensor according to claim 1, wherein the signal processing circuit has a low level when the detection signal is smaller than a first threshold value and a high level in other cases. A level discriminating section which outputs a second signal which becomes a low level when the detection signal is larger than a second threshold value and which becomes a high level in other cases, and a first and a second collectors whose emitters are connected to each other. Second
The first resistor having a collector connected to a predetermined DC voltage via a first resistor having a predetermined resistance value, the first signal being input to the base of the first transistor, and the predetermined resistor A configuration in which the second signal is input to the base of the second transistor whose emitter is coupled to another predetermined DC voltage via a second resistor having a resistance value substantially the same as the value. And a magnetic sensor that outputs the ternary digital signal to a connection point between the first transistor and the second transistor. 4. A magnetic detection means comprising a semiconductor thin film or a magnetic thin film, and a signal processing circuit for inputting a detection signal from the magnetic detection means and outputting a binary digital signal of a plurality of bits according to the level of the detection signal. A magnetic sensor comprising: