KR100720620B1 - Circuit for correcting outputs of magnetic sensor in accordance with pole of magnet, pointing apparatus and digital apparatus comprising the circuit thereof - Google Patents

Abstract

The present invention relates to a magnetic field sensor output correction circuit according to the polarity of the magnet, a pointing device including the correction circuit and a digital terminal. The correction circuit of the present invention compares the output of the magnetic field sensor in which the voltage of the output terminal is inverted with a predetermined reference value according to the polarity of the approaching magnet to determine whether the output of the magnetic field sensor is inverted, and corrects this to relate to the polarity of the magnet. Provides uninverted output without Such a correction circuit may be included in a pointing device in which a magnetic field sensor and a magnet are coupled to each other so that the polarity of the magnet may not be considered when assembling the magnet. Therefore, the work efficiency of the assembler who assembles the magnetic field sensor and the magnet into one set can be increased, and the production cost can be reduced.

Magnetic field sensor, output compensation, magnet, polarity

Description

Circuit for correcting outputs of magnetic sensor in according with pole of magnet, pointing apparatus and digital apparatus comprising the circuit

1 is a view briefly showing an example of a pointing device for determining the movement of a magnet using a magnetic field sensor,

2 is a circuit diagram of a magnetic field sensor output correction circuit according to the present invention, and

3 is a circuit diagram of a magnetic field sensor output correction circuit according to another exemplary embodiment of the present invention.

The present invention relates to a magnetic field sensor output correction circuit according to the polarity of the magnet, which controls to output the same output regardless of the polarity of the magnet by correcting the output of the magnetic field sensor that varies depending on the polarity of the magnet forming the external magnetic field.

The magnetic field sensor is a sensor for detecting a change in an external magnetic field, and includes a Hall sensor using a Hall effect and a magnetoresistive sensor using a magnetoresistive effect according to the physical phenomenon or effect used thereof.

A hall sensor is a sensor that uses a potential difference generated in a direction perpendicular to the current and the magnetic field, that is, a change in the hall voltage when a current is applied to a semiconductor substrate and the magnetic field is applied in a direction perpendicular to the flow of the current.

The hall sensor may be mounted in one assembly together with a magnet to detect and process a movement of the magnet by a user's manipulation, thereby receiving a user's manipulation.

The hall sensor may be represented by a bridge internal resistance, and the internal resistance changes in response to a change in an external magnetic field. In addition, depending on the polarity of the approaching magnet, the voltage output from the Hall sensor is inverted in polarity with respect to the reference voltage.

For example, if the output voltage of the output terminal has a positive value compared to the reference voltage when the N pole of the magnet approaches, and the absolute value thereof increases, the voltage of the output terminal in the same manner is approached when the S pole of the magnet approaches. When measured, the output voltage has a negative value compared to the reference voltage and its absolute value increases.

Therefore, the part of processing the output value of the hall sensor at the rear end of the hall sensor should be dependent on the polarity of the magnet mounted on the upper part of the hall sensor. In order not to do so, it must be assembled to have a certain magnet polarity corresponding to the configuration of the hall sensor. Such assembly limitations reduce the assembly efficiency and ultimately increase the production cost.

An object of the present invention is to provide a magnetic field sensor output correction circuit according to the polarity of the magnet, by controlling the output of the magnetic field sensor that is dependent on the polarity of the magnet forming the external magnetic field, and outputs the same output regardless of the polarity of the magnet. have.

It is still another object of the present invention to provide a pointing device and a pointing device capable of detecting a displacement of a magnet regardless of the polarity of the magnet assembled together by including a magnetic sensor output correction circuit according to the polarity of the magnet. It is to provide a digital terminal including.

According to the present invention for achieving the above object, the magnetic field sensor output correction circuit according to the polarity of the magnet includes a magnetic field sensor, an amplifier, a comparator, an inverting amplifier and a switching circuit.

In the magnetic field sensor, the magnitude of the voltage between the two output terminals changes in response to the approach of the external magnetic material, and the voltages between the output terminals are inverted from each other according to the polarity of the magnetic material, and the amplifier amplifies the voltage difference between the output terminals. To print.

The comparator compares the amplified voltage with a predetermined reference voltage, and outputs a voltage corresponding to one of logic 0 and 1 when the reference voltage is less than the reference voltage, and the inverting amplifier changes the sign of the voltage of the input signal.

The switching circuit switches the amplified signal to an input of the inverting amplifier so that the sign of the voltage of the signal matches when the amplified voltage is less than or equal to the reference voltage based on the output voltage of the comparator.

The magnetic field sensor output correction circuit according to the polarity of the magnet according to another embodiment of the present invention compares at least one of the magnetic field sensor, the at least one amplifier, and the amplified signal with a predetermined reference voltage so as to be less than or equal to a reference voltage. And a comparator for outputting a voltage corresponding to one of 1, at least one inverting amplifier for changing the sign of the voltage of the input signal, and when the amplified voltage is less than or equal to the reference voltage based on the output voltage of the comparator. And a switching circuit for switching each signal to an input of the at least one inverting amplifier so that the sign of the voltage of each signal is matched.

The pointing device according to another embodiment of the present invention may include a magnetic field sensor output correction circuit according to the polarity of the magnet to detect the displacement of the movement of the magnet.

The digital terminal according to another embodiment of the present invention includes a magnetic sensor output correction circuit according to a polarity of a magnet, and detects a displacement of the movement of the magnet according to a user's operation, thereby visually recognizing the displacement. Can be displayed.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In order to properly describe the present invention, the structure of FIG. 1 will be described first. Hereinafter, the magnetic field sensor output correction circuit of the present invention will be described based on FIG.

1 is a view briefly illustrating a part of a pointing device for determining a movement of a magnet by using a magnetic field sensor.

The magnetic field sensor used in the present invention may include a Hall sensor, a magnetoresistive sensor, and the like. However, hereinafter, it will be described based on the Hall sensor of the magnetic field sensor for the convenience of description.

Referring to FIG. 1, a pointing device 100 includes a magnet 130 mounted on a plurality of Hall sensors 101 and 103, and a magnet 130 between the magnet 130 and the Hall sensors 101 and 103. ) Has a structure in which a frame 150 is formed to form a space in which it can move. The outputs of the hall sensors 101 and 103 are connected to a predetermined position determining unit 105 for detecting the displacement of the magnet 130. The pointing device 100 is a portable device such as a mobile phone equipped with a display device, an MPEG Audio Layer-3 (MP3) player, a portable multimedia player (PMP), and a personal digital assistant (PDA). (portable) may be included in a digital device.

The hall sensors 101 and 103 have four terminals and receive driving power through two terminals, and output signals in response to changes in the magnetic field through the other two terminals to detect the movement of the magnet 130. Can be.

The magnet 130 has a flat plate structure, one side of which is an N pole, and the other side thereof is an S pole.

In response to the change in the magnetic field as the magnet 130 slides on the frame, each of the hall sensors 101 and 103 outputs a predetermined signal. Typically, the signal of the signal becomes larger as the magnet 130 approaches.

When the output terminal voltage is measured based on one of the output terminals, the N pole of the magnet faces the Hall sensors 101 and 103 and the S pole of the magnet 130 faces the Hall sensors 101 and 103. The signs of the voltages output by the hall sensors 101 and 103 are opposite to each other.

For example, suppose that the voltage between the output terminals is detected based on one of the output terminals of the hall sensors 101 and 103. When the N-poles are assembled to face downward as shown in FIG. 1, when the Hall sensors 101 and 103 are connected such that the output terminal voltage of the Hall sensors 101 and 103 becomes (+) relative to the reference voltage, the magnet 130 In contrast to FIG. 1, when the S pole is connected to the hall sensors 101 and 103, the output terminal voltage of the hall sensors 101 and 103 becomes (−) relative to the reference voltage.

The magnetic field sensor output correction circuit of the present invention may be based on the structure of FIG. 1, but the structure of FIG. 1 is an example and is not limited thereto. For example, the magnet 130 and the Hall sensors 101 and 103 may be disposed on substantially the same plane. That is, the magnetic field sensor output correction circuit of the present invention may operate in the same manner as in Fig. 1 and other structures corresponding to the aforementioned examples.

The magnetic field sensor output correction circuit of the present invention receives the outputs of the Hall sensors 101 and 103 and processes them by a predetermined method, thereby outputting signals having the same signs regardless of the polarity of the magnet 130 to the circuit of the next step. do. Through this, the polarity of the magnet 130 may not be considered in the assembly process of the pointing device 100 of FIG. 1. The magnetic field sensor output correction circuit of the present invention may be included in the position determining unit 105 of the pointing device 100 or positioned at the front end thereof to provide a corrected signal to the position determining unit 105.

2 is a circuit diagram of a magnetic field sensor output correction circuit according to the present invention. Hereinafter, the magnetic field sensor output correction circuit of the present invention will be described with reference to FIG. 2, based on a Hall sensor among magnetic field sensors. However, the circuit of FIG. 2 is not limited to the structural situation of FIG.

The hall sensor 201 receives the driving power source V _CC and outputs a predetermined voltage Va between the output terminals 3 and 4 in response to the movement of the external magnet 130. In another driving method, a constant current may be applied to maintain the hall voltage Va. Since voltage Va is a very small value, it needs to be amplified to a certain level of voltage.

The amplifier 203 outputs the voltage V _{b obtained} by amplifying the voltage Va between the output terminals 3 and 4 of the hall sensor 201 to a predetermined level to the comparator 205 and the switching circuit 207. When the voltage of the output terminal 3 is higher than the output terminal 4, the voltage V _b amplified by the amplifier 203 outputs a voltage having a positive sign relative to the reference voltage, and the voltage of the output terminal 4 is the output terminal. If the voltage is higher than the voltage in (3), the voltage with the minus sign is compared with the reference voltage. For example, when the N pole of the magnet 130 approaches, if the voltage of the output terminal 3 is higher than the voltage of the output terminal 4, the amplifier output voltage V _b will have a positive value compared to the reference voltage. . When the S pole of the magnet approaches, the amplifier output voltage V _b has a negative value compared to the reference voltage.

The comparator 205 determines the sign of the output voltage Va of the amplifier 203, that is, the output voltage Va of the hall sensor 201 by comparing the output voltage V _b of the amplifier 203 with a predetermined reference voltage V _ref . . As a result, the comparator 205 may determine the polarity of the assembled magnet 130. In this case, the reference voltage V _ref is preferably 0 V.

The output voltage Vc of the comparator 205 becomes equal to the driving voltage V _CC when the output voltage V _b of the amplifier 203 is higher than the reference voltage V _ref , and 0 V is equal to the output voltage V _b when the output voltage V _b is lower than the reference voltage V _ref . do. The output of the comparator 205 controls the switching circuit 207.

When the output voltage Vc of the comparator 205 is V _CC , the switching circuit 207 bypasses the output voltage V _b of the amplifier 203 as it is and outputs it to V _out1 , and output voltage Vc of the comparator 205. Is 0, the output voltage V _b of the amplifier 203 is output to the input of the inverting amplifier 209.

The inverting amplifier 209 outputs V _out2 which inverts the output of the switching circuit 207 with a predetermined amplification degree.

Furthermore, the amplification degree, or the one of the inverting amplifier 209, in the rear end (not shown) of the V _out1 is desirable to amplify the V _out1 as the amplification degree of the inverting amplifier 209.

Thus, even if the output of the Hall sensor 201 is reversed by changing the polarity of the external magnet 130, the magnetic sensor output correction circuit 200 of the present invention outputs a signal having the same sign.

3 is a circuit diagram of a magnetic field sensor output correction circuit according to another exemplary embodiment of the present invention.

In the magnetic field sensor output correction circuit 300 according to the embodiment of FIG. 3, the first hall sensor 301 and the second hall sensor 303 are disposed below the frame 150 horizontally installed on the bottom surface as shown in FIG. 1. Is disposed on approximately one axis, and the magnet 305 is disposed on the frame 150 so as to correspond to the first hall sensor 301 and the second hall sensor 303. By moving on the Hall sensor 301 and the second Hall sensor 303, it can be applied to the case of detecting the displacement in the axial direction (d) of the movement of the magnet 305. The magnet 305 may be assembled such that one of the N pole and the S pole approaches the first hall sensor 301 and the second hall sensor 303.

In this case, the first hall sensor 301 and the second hall sensor 303 are preferably arranged to output a voltage having the same sign with respect to the movement of the magnet 305. In other words, when the magnet 305 is assembled such that the N pole faces the first hall sensor 301 and the second hall sensor 303, the first hall sensor 301 and the second hall sensor 303 are the same. It is preferable to output the voltage of the sign.

When the magnet 305 moves from the position of a to the position of b or the position of c, voltages Va ₁ and Va ₂ are output to the output terminals of the first hall sensor 301 and the second hall sensor 303, respectively.

The first amplifier 307 and the second amplifier 309 receive voltages Va ₁ and Va ₂ , respectively, and output the amplified voltages V _b1 and V _b2 , respectively. Operations of the first hall sensor 301, the second hall sensor 303, the first amplifier 307, and the second amplifier 309 are the same as those of the hall sensor 201 and the amplifier 203 of FIG. 2. .

The voltages V _b1 and V _b2 are input to the adder 311 and added. The value obtained by adding the voltages V _b1 and V _b2 is input to the comparator 313 and compared with a predetermined reference value V _ref , thereby outputting the output voltages Va ₁ and Va ₂ of the _first and second hall sensors 301 and 303. Determine the sign.

According to an embodiment, the first amplifier 307, the output voltage Va ₁ and a second amplifier 309. The output voltage is also a magnet (305) in a manner corresponding to 2 by entering only one of Va ₂ to the comparator 313 of the Know the polarity. In this case, the magnitude of the voltage output from the first amplifier 307 or the second amplifier 309 output due to an error in the assembly of the magnet 305 may cause the comparator 313 to operate substantially. It may not be in range. Therefore, when using the output of the plurality of Hall sensors, it is preferable to add the output of the two Hall sensors to compare.

The output voltage of the comparator 313 is input to the switching circuit 315, and the output of the switching circuit 315 is connected to the input terminals (+) and (-) of the third amplifier 317, respectively. According to the control of the comparator 313, the switching circuit 315 inputs the voltage V _b1 to the positive terminal of the third amplifier 317 and the voltage V _b2 to the negative terminal of the third amplifier 317. Or vice versa to control to output the voltage V _out of the same sign regardless of the polarity of the magnet 305.

For example, when the N pole of the magnet 305 is assembled to face the first hall sensor 301 and the second hall sensor 303, the first hall sensor 301 and the second hall sensor 303 may be separated. Assume that the states Va ₁ and Va ₂ based on the output terminal 4 are arranged to be positive with respect to the reference voltage.

When the assembled magnet 305 actually comes to the position b, if the polarity of the magnet is N pole, the output voltages V _b1 and V _{b2 of} the first amplifier 307 and the second amplifier 309 are also positive (+) relative to the reference voltage. Value (| V _b1 |> | V _b2 |), and the output of the comparator 313 has a Vcc value, so that the switching circuit 315 is connected to the third amplifier 317 as drawn in solid line in FIG. do. Therefore, the output of the third amplifier 317 also has a positive value compared to the reference voltage.

If the S pole of the actually assembled magnet 305 is assembled to face the first hall sensor 301 and the second hall sensor 303, the first hall sensor 301 and the second hall sensor 303 may be separated. The output terminal voltages Va ₁ and Va ₂ have a negative value compared to the reference voltage (| Va ₁ |> | Va ₂ |), and the output voltages V _b1 , of the first amplifier 307 and the second amplifier 309. V _b2 also has a negative value (| V _b1 |> | V _b2 |), and the output of the comparator 313 becomes 0V. Thus, the switching circuit 315 is connected to the third amplifier 317 in the manner shown by the dotted lines in FIG. Therefore, the output of the third amplifier 317 is inverted to have a positive value relative to the reference voltage.

In this case, however, the output of the third amplifier 317 is not always positive compared with the reference voltage.

For example, when the magnet 305 is the N pole and comes to the position c, the output voltages V _b1 and V _b2 also have a positive value compared to the reference voltage, and the absolute voltage is | V _b1 | <| V _b2 |, the output voltage V _out of the third amplifier 317 is inverted. Accordingly, as shown in FIG. 3, the output V _out of the third amplifier 317 has a negative value compared to the reference voltage as the position of the magnet 305 approaches c after passing a.

When the magnet 305 is the S pole and is at the position c, the output voltages V _b1 and V _b2 also have a negative value compared to the reference voltage, and the absolute value is | V _b1 | <| V _b2 |, the input of the third amplifier 317 is reversed from that of the N pole by the control of the comparator 313. Therefore, the output V _out of the third amplifier 317 has a negative value with respect to the reference voltage.

When the amplification degree of the first to third amplifiers (307, 309, 317) is 1, each output voltage example according to an embodiment of the present invention is summarized as shown in Table 1 below.

Herein, the output voltages Va ₁ and Va ₂ of the first amplifier 307 or the second amplifier 309 at the a, b, and c positions are the a, b, and c positions, and the first hall sensor 301 and the first voltage. The value is assumed in consideration of the position of the two-hole sensor 303, and it is assumed that the two hall sensors 301 and 303 are arranged to output a positive value relative to the reference voltage when the N pole approaches.

Magnet polarity Magnet position V _b1 (mV) = Va ₁ V _b2 (mV) = Va ₂ Vc V _out (mV)  N a +15 +15  Logic H 0 b +25 +5 +20 c +5 +25 -20  S a -15 -15  Logical L 0 b -25 -5 +20 c -5 -25 -20

Referring to Table 1, even though the polarity is the S pole or the N pole, when the magnet 305 moves from a to b or c, the output V _out corrected in the correction circuit 300 of the present invention has the same value. Have.

According to another embodiment of the present invention, one of the output terminals 3 and 4 of the first hall sensor 301 and the second hall sensor 303 (for example, terminal 4) is applied with a constant voltage, and V _{ref The} same effect can be obtained by adjusting other voltages correspondingly.

The magnetic field sensor output correction circuit and the plurality of magnetic field sensors of the present invention may be included in one multi chip package (MCP) or multi chip module (MCP), and as described above, various pointing devices The pointing device may be included in a digital terminal or the like and used in a user input device such as a mouse.

While the above has been shown and described with respect to preferred embodiments of the invention, the invention is not limited to the specific embodiments described above, it is usually in the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or prospect of the present invention.

As described above, the magnetic field sensor output correction circuit according to the polarity of the magnet of the present invention corrects the output of the magnetic field sensor in which the voltage of the output terminal is inverted according to the polarity of the approaching magnet, thereby not being inverted regardless of the polarity of the magnet. Provide the output.

Such a correction circuit is included in a pointing device that detects displacement of the magnet movement by combining the magnetic sensor and the magnet, or a digital device including the pointing device, so that the polarity of the magnet may not be considered when assembling the magnet. can do.

Therefore, in the production of such a pointing device or a digital device, it is possible to increase the work efficiency of the assembler for assembling the magnetic field sensor and the magnet into one set, and to reduce the production cost.

Claims (6)

A magnetic field sensor having a magnitude change in voltage between two output terminals in response to an approach of an external magnetization body, and inverting voltages between the output terminals according to polarities of the magnetization bodies; An amplifier for amplifying and outputting a voltage between the output terminals; A comparator comparing the output of the amplifier with a predetermined reference voltage and outputting a voltage corresponding to one of logic 0's and 1's when the output voltage is less than or equal to the reference voltage; An inverting amplifier for changing a sign of a voltage of an input signal; And The output of the amplifier is switched to the final output, and if the output of the amplifier is less than the reference voltage based on the output of the comparator by switching the output of the amplifier to the input of the inverting amplifier, the sign of the voltage of the final output is And a switching circuit which does not change depending on the polarity of the magnetic material. The magnetic field sensor output correction circuit according to the polarity of the magnet. A plurality of magnetic field sensors arranged so that the magnitudes of voltages between the two output terminals vary in response to the approach of one external magnetization body, and the signs of the voltages outputted according to polarities of the magnetization bodies are the same; A plurality of amplifiers for amplifying and outputting voltages between output terminals of the plurality of magnetic field sensors; A comparator comparing one of the outputs amplified by the plurality of amplifiers with a predetermined reference voltage and outputting a voltage corresponding to one of logic 0 and 1 when the reference voltage is less than the reference voltage; A plurality of inverting amplifiers for changing a sign of a voltage of an input signal; And Switching the outputs of the plurality of amplifiers to a final output, respectively, and switching the plurality of amplifier outputs to the inputs of the plurality of inverting amplifiers when the outputs of the plurality of amplifiers are below the reference voltage based on the output voltage of the comparator. And a switching circuit such that the sign of the voltage of the final output does not change according to the polarity of the magnetized material. A plurality of magnetic field sensors arranged so that the magnitudes of voltages between the two output terminals vary in response to the approach of one external magnetization body, and the signs of the voltages outputted according to polarities of the magnetization bodies are the same; A plurality of amplifiers for amplifying and outputting voltages between output terminals of the plurality of magnetic field sensors; An adder for adding outputs of the plurality of amplifiers; A comparator comparing the output of the adder with a predetermined reference voltage and outputting a voltage corresponding to one of logic 0's and 1's when the output voltage is less than or equal to the reference voltage; A differential amplifier for amplifying the difference between two input voltages; Switching the outputs of the plurality of amplifiers to the inputs of the + or-terminal of the differential amplifier, respectively, each output of the plurality of amplifiers is input when the output signal of the adder is less than the reference voltage based on the output voltage of the comparator Magnetic field sensor according to the polarity of the magnet comprising a; switching circuit for switching the + or-terminal of the differential amplifier to be changed, so that the sign of the voltage of the plurality of amplifier output does not change depending on the polarity of the magnetized body Output correction circuit. The method according to any one of claims 1 to 3, The magnetic field sensor applies a constant voltage to one of the output terminals so that the voltage between the output terminals changes as the voltage of the remaining terminals changes in response to the approach of the magnetic material. The reference voltage is the magnetic field sensor output correction circuit according to the polarity of the magnet, characterized in that the constant voltage. Pointing device for detecting the displacement of the movement of the magnet including a magnetic sensor output correction circuit according to the polarity of the magnet according to any one of claims 1 to 3. The magnetic sensor output correction circuit according to the polarity of the magnet according to any one of claims 1 to 3, including the detection of the displacement of the movement of the magnet according to the user's operation, to visually recognize the displacement. Digital terminals that can be displayed to help.

Images