JP4945995B2 - Geomagnetic detector - Google Patents

Description

  The present invention relates to a geomagnetism detecting device having a geomagnetism detecting element for detecting a perpendicular axis component of geomagnetism, and more particularly to an apparatus having a thermally deformable nonvolatile memory element for storing correction information of detection output of the geomagnetism detecting element.

  In general, an LSI (Large Scale Integrated Circuit) that performs geomagnetic detection by mounting magnetic sensors in two orthogonal axes on a chip has means for correcting the sensitivity of the geomagnetic sensor.

  For example, Patent Document 1 discloses a technique for correcting detection output of a magnetic sensor by arithmetic processing. According to the technique described in this document, correction of the detection output of the X-axis detection unit is performed as follows. That is, the detection range of the magnetic sensor is divided into 4 blocks every 90 degrees, the maximum output voltage value of the X-axis detection unit is A1, and the X-axis at the point where the output value of the Y-axis detection unit is rotated 90 degrees from the zero position The output voltage value of the detection unit is A2.

Then, when the output voltage value A2 is on the + side, it is classified on the-side, or on the minus side, and when it is on the + side, the equation (1) is used as a correction equation, and when it is on the-side, (2). The formula is a correction formula, and if it is very small, no correction is made.
[ABS (A3) + ABS (A2)] · Z (1)
[ABS (A3) + ABS (A2)] / Z (2)
However, A3 is the actual measurement output of the X-axis detector, and Z is the correction parameter shown in the equation (3).
Z = A1 / [A1-ABS (A2)] (3)
The Y axis is corrected by the same method, and the orthogonality of the X axis detection unit and the Y axis detection unit is corrected.

  Thus, when correcting the detection output of a magnetic sensor by arithmetic processing, it can take the form which measures correction data, for example by a shipping inspection, and writes it in the non-volatile memory mounted in LSI.

Recently, in response to a request for lowering the voltage of this type of LSI, there is a non-volatile memory mounted with a heat-transformed fuse memory that can perform suitable reading even at a low voltage.
JP 2000-180170 A

  However, while the fuse memory has the above-mentioned advantages, it is necessary to pay attention to the circuit scale because the fuse cutting transistor used at the time of writing requires a large capacity. For this reason, in the form in which the value of the correction data obtained at the time of shipping inspection is directly written in the fuse memory, a large number of fuse memories are required, which is inconvenient in circuit design.

  In view of such circumstances, the present invention provides a geomagnetism detecting device having a geomagnetism detecting element for detecting a perpendicular axis component of geomagnetism and a thermally deformable nonvolatile memory element for storing correction information of detection output of the geomagnetism detecting element. It is an object of the present invention to provide a technique capable of reducing the number of thermally deformable nonvolatile memory elements.

  In order to solve the above-mentioned problems, a first aspect of the present invention provides a geomagnetism detecting element for detecting a perpendicular axis component of geomagnetism, and a thermally deformable non-volatile memory element for storing correction information of detection output of the geomagnetism detecting element. The correction information is an axis sensitivity correction coefficient and an inter-axis correction coefficient, and is a value expressed as a ratio to the axis sensitivity correction coefficient of any axis. A geomagnetic detection device is provided.

  According to a second aspect of the present invention, in the geomagnetism detecting device according to the first aspect, the nonvolatile storage element stores at least correction information related to an axis sensitivity correction coefficient other than the axis sensitivity correction coefficient of any of the axes. Provided is a geomagnetism detecting device characterized in that it is a thing.

  According to a third aspect of the present invention, in the geomagnetic detection device according to the second aspect, as the correction information related to the axial sensitivity correction coefficient other than the axial sensitivity correction coefficient of any one of the axes, the axial sensitivity correction coefficient of the axial sensitivity correction coefficient There is provided a geomagnetism detecting device using a difference value obtained by subtracting a preset reference value from a ratio to the above.

  According to a fourth aspect of the present invention, in the geomagnetic detection device according to any one of the first to third aspects, a correction arithmetic circuit for performing a correction calculation of a detection output of the geomagnetism detection element is provided, and the correction calculation circuit includes an axis sensitivity correction for the detection output. A correction value of the detection output is calculated by adding the correction term obtained by multiplying the detection output of the other axis by the correction coefficient obtained by multiplying the detection output of the other axis by the correction coefficient. Providing equipment.

  According to a fifth aspect of the present invention, in the geomagnetic detection device according to the fourth aspect of the invention, a correction arithmetic circuit that performs a correction calculation of the detection output of the geomagnetism detection element is provided, and the correction calculation circuit uses the reference value as the difference value. Provided is a geomagnetism detecting device characterized in that a correction operation is performed after adding and restoring an axis sensitivity correction coefficient.

  According to a sixth aspect of the present invention, in the geomagnetism detecting device according to the fourth or fifth aspect, the correction calculation circuit calculates a correction coefficient that cannot be acquired from the correction information by substituting a preset alternative value. Provided is a geomagnetism detecting device characterized in that it is a thing.

 According to a seventh aspect of the present invention, there is provided a geomagnetism detecting element for detecting geomagnetism for each orthogonal axis component and a heat-transformed non-volatile memory for storing one or a plurality of correction data for correcting the detected geomagnetism value. Each of the correction data is an axis sensitivity correction coefficient, an inter-axis correction coefficient, or a difference value obtained by subtracting a predetermined reference value from the axis sensitivity correction coefficient. It is expressed as a value of the ratio of the axis of the axis to the axis sensitivity correction coefficient.

   The invention according to claim 8 is the geomagnetic detection device according to claim 7, wherein at least one of the correction data is an axis sensitivity correction coefficient of any one of the axes other than the axis sensitivity correction coefficient other than the one of the axes. Provided is a geomagnetism detecting device characterized by having a ratio value to

   The invention according to claim 9 is the geomagnetism detection device according to claim 7, wherein at least one of the correction data is a difference value obtained by subtracting a predetermined reference value from an axis sensitivity correction coefficient other than any of the axes. Provided is a geomagnetism detecting device characterized in that it is a value of a ratio of any one of the axes to an axis sensitivity correction coefficient.

   A tenth aspect of the present invention is the geomagnetic detection device according to the seventh aspect, further comprising a correction arithmetic circuit for correcting a value of geomagnetism for each orthogonal axis component detected by the geomagnetic detection element, wherein the correction arithmetic circuit is Any one of the axis sensitivity correction coefficient of the predetermined axis component or a difference value obtained by subtracting a predetermined reference value from the axis sensitivity correction coefficient of the predetermined axis component to the geomagnetic value of the predetermined axis component A value obtained by multiplying the ratio of the axis to the axis sensitivity correction coefficient by an addition value obtained by adding a predetermined value and the value of the geomagnetism of the other axis component to the axis sensitivity correction coefficient of any one of the axis correction coefficients. A corrected geomagnetism value is obtained by calculating a sum of a multiplication value obtained by multiplying a ratio value with respect to a geomagnetic detection device.

   The eleventh aspect of the present invention is the geomagnetic detection device according to the seventh aspect, further comprising a correction arithmetic circuit that corrects a value of geomagnetism for each orthogonal axis component detected by the geomagnetic detection element, wherein the correction arithmetic circuit includes: Any one of the axis sensitivity correction coefficient of the predetermined axis component or a difference value obtained by subtracting a predetermined reference value from the axis sensitivity correction coefficient of the predetermined axis component to the geomagnetic value of the predetermined axis component Provided is a geomagnetism detection device characterized in that a corrected geomagnetism value is obtained by calculating a multiplication value obtained by multiplying an addition value obtained by adding a predetermined value to a ratio of an axis to an axis sensitivity correction coefficient.

  According to a twelfth aspect of the present invention, there is provided the geomagnetism detecting apparatus according to the seventh aspect, wherein the thermally deformable nonvolatile memory element is a fuse memory.

  The invention according to claim 13 provides the geomagnetism detecting apparatus according to claim 7, wherein the predetermined reference value is an axis sensitivity correction coefficient of any one of the axes.

  As described above, according to the present invention, since the information obtained by taking the ratio of the other correction coefficient to the axial sensitivity correction coefficient of any axis is stored as correction information in the non-volatile memory element of thermal deformation molding, The correction information can be miniaturized and the storage capacity of the thermally deformable nonvolatile memory element can be reduced while maintaining the correction accuracy by performing the above correction.

  In addition, the axis sensitivity correction coefficient and the inter-axis correction coefficient of any axis can be omitted from the correction information, and the correction information can be further miniaturized to reduce the storage capacity of the nonvolatile memory element.

  Further, by using the difference value obtained by subtracting the reference value from the sensitivity correction coefficient of the other axis as the correction information, the correction information can be further miniaturized and the storage capacity of the nonvolatile memory element can be reduced.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing an outline of the configuration of a geomagnetic detection LSI according to the first embodiment of the present invention.

  As shown in the figure, the LSI 1 has a power supply terminal 2, a ground terminal 3, a chip select input terminal 4, a data input terminal 5, and a data output terminal 6. The power supply line and ground line wiring to each part are not shown.

  The interface circuit 7 transmits / receives a chip select signal / input / output signal to / from a master chip (not shown). The control circuit 8 operates with a predetermined logic based on an instruction from the master chip and controls each unit. The internal oscillation circuit 9 gives clock pulses to the control circuit 8 and other circuits.

  The magnetic sensor 10 in the X-axis direction and the magnetic sensor 11 in the Y-axis direction are magnetic sensors using magnetoresistive elements or the like. The switching circuit 12 operates under the control of the control circuit 8 and selectively switches the detection output of the magnetic sensors 10 and 11 to the input terminal of the amplifier 13. The amplifier 13 amplifies the detection outputs of the magnetic sensors 10 and 11 and supplies the amplified output to the A / D conversion circuit 14. The A / D conversion circuit 14 digitizes the detection output and outputs it to the control circuit 8.

The fuse memory 15 is a memory for storing detection output correction data and other data measured at the time of shipping inspection. (C) One of the values of D1, D2, and D4 and (D) the value of D4 are stored. The correction data D1 to D4 are shown in equations (4) to (7).
D1 = a12 / a11 (4)
D2 = a21 / a11 (5)
D3 = a22 / a11 (6)
D4 = a22 / a11-1 (7)
However, aij (i = 1 or 2, j = 1 or 2) is a correction coefficient described later.

  FIG. 2 is a block diagram illustrating a configuration example of the fuse memory. The figure shows an example in which four memory cells d0 to d3 are connected in a daisy chain to form a 4-bit scan path. With this configuration, correction data of the detection output can be stored as 4-bit information. In FIG. 2, a logic element marked with a “+” symbol represents a NOR gate, and a logic element marked with a “.” Symbol represents an AND gate.

In each of the memory cells d0 to d3, 21 is a fuse made of a polysilicon resistor or the like, 22 is an N-type FET (field effect transistor), 23 is a data flip-flop circuit, and 24 is a 3-input FET that provides a gate voltage to the FET 22. The NOR gate 25 is composed of a 2-input AND gate and a 2-input NOR gate, and is a 3-input logic gate for outputting output data to a subsequent memory cell that is daisy chained.
Hereinafter, the configuration of the memory cell d0 will be described, but the other memory cells d1 to d3 have a common configuration. A bit for writing is input to the D terminal (data input terminal) of the data flip-flop circuit 23, and a ck signal (clock pulse) is supplied to the CK terminal (clock input terminal). One input terminal of the NOR gate 24 is connected to the O terminal (positive logic output terminal) of the data flip-flop circuit 23, an inverted signal of the ck signal is supplied to the other input terminal, and the other input terminal is connected to the other input terminal. The / write signal is supplied. The gate of the FET 22 is connected to the output terminal of the NOR gate 24, and its drain is grounded. One end of the fuse 21 is connected to the power supply voltage VDD, and the other end is connected to the source of the FET 22. A read signal is supplied to one input terminal of the AND gate constituting the logic gate 25, and the other input terminal is connected to the source of the FET 22. One input terminal of the NOR gate constituting the logic gate 25 is connected to the ON terminal (negative logic output terminal) of the data flip-flop circuit 23, and the other input terminal is connected to the output terminal of the AND gate constituting the logic gate 25. Has been. The output terminal of the logic gate 25 is connected to the D terminal of the data flip-flop circuit 23 of the daisy chained memory cell d1.

  When writing data to the memory cell d0, a write bit is sent from the input terminal / di of the memory cell d0, and at the timing when this bit is sent to the desired cell, the / write signal is supplied to the NOR gate 24 as a low level. To do. As a result, the output W0 of the NOR gate 24 becomes Hi level, the FET 22 is turned on, and the fuse 21 is energized and blown. The state shown in FIG. 2 indicates that, for example, data is written in the memory cells d0 and d2, and the respective fuses 21 are blown. That is, data “1” (Low level) is stored in the memory cell d0, data “0” (Hi level) is stored in the memory cell d1, “1” (Low level) is stored in the memory cell d2, and data “1” is stored in the memory cell d3. 0 ″ (Hi level) is stored.

  When data is read from each memory cell, after the data flip-flop 23 is reset, the read signal is set to the Hi level, so that the presence or absence of the fuse 21 is reflected in the output of the logic gate 25. In this state, a scan-out operation is performed, and the output of each cell is taken out from the output terminal do via the logic gate 25 of the memory cell d3 in the final stage.

  Returning to FIG. 1, the control circuit 8 controls the switching circuit 13 to capture the detection outputs Sx and Sy of the magnetic sensors 10 and 11 into the A / D conversion circuit 14, and the A / D conversion circuit 14 detects the detection output. Sx and Sy are digitized and loaded into a register (not shown) in the control circuit 8. Then, the correction data is read from the fuse memory 15 to correct the detection outputs Sx and Sy and output to the interface circuit 7.

  Further, the correction for the detection outputs Sx and Sy may be performed as follows instead of the control circuit 8. That is, the LSI is provided with a function of outputting data stored in the fuse memory, and Sx and Sy before correction are output from the LSI. On the master side, Sx and Sy are corrected by software processing based on the separately received fuse memory data.

  Next, correction processing of the detection outputs Sx and Sy will be described. First, the detection outputs Sx, Sy and the magnetic fields Hx, Hy on the magnetic sensors 10, 11 have the relationship shown in the equation (8).

  However, aij (i = 1 or 2, j = 1 or 2) is a correction coefficient, a11 is an X-axis sensitivity correction coefficient (= 1 / X-axis sensitivity), a22 is a Y-axis sensitivity correction coefficient (= 1 / Y-axis sensitivity), a12 , A21 are inter-axis correction coefficients.

In an ideal magnetic sensor, a11 = a22 and a12 = a21 = 0, but in an actual magnetic sensor, a11 ≠ a22, a12 ≠ a21 ≠ 0, and this correction processing is necessary.
In the first embodiment, correction processing is performed based on one of the following correction calculation methods A to D.

[Calculation method A]
Considering the characteristics of the geomagnetic sensor, it is not necessary to obtain the absolute value of the magnetic field in order to measure the azimuth, and only the ratio of each component of the magnetic field is required. For this reason, if three values of a12 / a11, a21 / a11, and a22 / a11 are obtained, it is sufficient for correction calculation in the use as a geomagnetic sensor.

  Therefore, in the calculation method A, the correction process is performed by the equation (9) using the values of the correction data D1 to D3 stored in the fuse memory.

  However, Sx ′ and Sy ′ are detection outputs after correction.

  According to the equation (9), the correction data related to the X-axis sensitivity correction coefficient a11 is theoretically 1 as a11 / a11 = 1, so that the correction calculation can be performed without any trouble without storing the correction data in the fuse memory. Can be executed.

  Therefore, in this calculation method A, for example, a fixed value “1” is set, and the correction calculation is performed by substituting the fixed value “1” for the X-axis sensitivity correction coefficient. This reduces the number of correction data to be stored in the fuse memory by one and reduces the total amount of correction data. If the data length of each correction data is, for example, a value of 6 bits, the total data amount of the correction coefficients a11, a12, a21, and a22 is 24 bits, whereas according to the calculation method A, the correction data D1, The total amount of D2 and D3 is 18 bits.

[Calculation method B]
In this calculation method, focusing on the fact that a12 / a11 and a21 / a11 obtained by dividing the inter-axis correction coefficient by the axis sensitivity correction coefficient are close to “0”, for example, a fixed value “0” is set, and a12 / Correction processing is performed using equation (10) obtained by substituting the values of a11 and a21 / a11 with fixed values.

  According to this calculation method, since the number of necessary correction data can be reduced to one, the total amount of correction data can be reduced to 6 bits corresponding to one correction data.

[Calculation method C]
In this calculation method, correction processing is performed using equation (11).

According to this calculation method, focusing on the fact that a22 / a11 obtained by dividing the axis sensitivity correction coefficient by the axis sensitivity correction coefficient is a value close to “1”, for example, a reference value “1” is set, and this reference value and By taking the difference of a22 / a11 and using it as correction data, the data length of the correction data is shortened. Incidentally, D4 + 1 = a22 / a11 , i.e. a D4 = (a22-a11) / a11, a11 obtained by subtracting in the molecular of the formula is an example of the "predetermined reference value" in claims.

  That is, the probability that the correction data D1 and D2 are originally small values is high, and the probability that the correction data D1 and D2 are small values is high because D4 is also a difference from the reference value “1”, so that each data length can be shortened. . Here, if the bit length of each correction data is shortened from 6 bits to 4 bits, the amount of data to be stored in the fuse memory is reduced to a total of 12 bits of correction data D1, D2, and D4.

[Calculation method D]
In this calculation method D, focusing on the fact that a12 / a11 and a21 / a11 obtained by dividing the inter-axis correction coefficient by the axial sensitivity correction coefficient are close to “0”, correction processing is performed using equation (12). The total amount of correction data is reduced by adopting both the reduction in the number of correction data described in the calculation method B and the reduction in the data length of the correction data described in the calculation method C.

  That is, the value of a12 / a11, a21 / a11 is replaced with a fixed value (for example, “0”) as in the calculation method B, and the reference value of the a22 / a11 (for example, “1”) as in the calculation method C. The difference is used as correction data.

  According to this calculation method, the number of correction data can be reduced to one as in method B, and the data length can be reduced to, for example, 4 bits as in method C. That is, the total amount of correction data can be reduced to 4 bits, which is the data length of the correction data D4.

  Next explained is the second embodiment of the invention. In the second embodiment, an application example to a geomagnetism detection device including a geomagnetic sensor with three orthogonal axes is shown. This geomagnetism detection device detects geomagnetism of three orthogonal axes using an LSI having the same configuration as the LSI shown in FIG.

  In the fuse memory of this apparatus, (E) values of D1 to D3, D5 to D9 or (F) values of D3 and D9, (H) D1, D2, and D4 are used as correction data of detection outputs measured at the time of shipping inspection. One of the values of .about.D8 and D10 and (G) values of D4 and D10 is stored.

Correction data D5 to D10 are shown in equations (13) to (18).
D5 = a13 / a11 (13)
D6 = a23 / a11 (14)
D7 = a31 / a11 (15)
D8 = a32 / a11 (16)
D9 = a33 / a11 (17)
D10 = a33 / a11-1 (18)
However, aij (i = 1 or 2, j = 1 or 2) is a correction coefficient described later.

  Here, the magnetic detection forces Sx, Sy, Sz and the magnetic fields Hx, Hy, Hz on the magnetic sensor have the relationship shown in the equation (19).

  However, aij (i = 1-3, j = 1-3) is a correction coefficient, a11 is an X-axis sensitivity correction coefficient (= 1 / X-axis sensitivity), and a22 is a Y-axis sensitivity correction coefficient (= 1 / Y-axis). Sensitivity), a33 is a Z-axis sensitivity correction coefficient (= 1 / Z-axis sensitivity), and a12, a13, a21, a23, a31, a32 are inter-axis correction coefficients.

  In the second embodiment, correction processing is performed based on one of the following correction calculation methods E to H.

[Calculation method E]
In the calculation method E, as in the calculation method A, correction processing is performed using the equation (20) from the viewpoint that the ratio of each component of the magnetic field is sufficient for use as a geomagnetic sensor.

  However, Sx ′, Sy ′ and Sz ′ are detection outputs after correction.

  If the data length of the correction data is, for example, a value of 6 bits, a storage capacity of 54 bits is required to store the nine correction coefficients a11 to a33. Since it is sufficient to store the eight correction data D1 to D3 and D5 to D9, the necessary storage capacity can be reduced to 48 bits.

[Calculation method F]
In this calculation method, similarly to the calculation method B, a12 / a11, a13 / a11, a21 / a11, a23 / a11, a31 / a11, a32 / a11 obtained by dividing the inter-axis correction coefficient by the axis sensitivity correction coefficient are “0”. Focusing on the fact that the values are close to each other, the values of a12 / a11, a13 / a11, a21 / a11, a23 / a11, a31 / a11, a32 / a11 are replaced with fixed values (for example, “0”), and (21 ) Is used for correction processing.

  According to this calculation method, the correction data replaced with the fixed value “0” does not need to be stored in the fuse memory, and the total amount of correction data can be reduced accordingly. That is, since only the correction data D3 and D9 need to be stored, the total amount of necessary correction data D3 and D9 is reduced to 12 bits.

[Calculation method G]
According to this calculation method, focusing on the fact that a22 / a11 and a33 / a11 obtained by dividing the axis sensitivity correction coefficient by the axis sensitivity correction coefficient are close to “1”, the reference value (“1” in this example) The data length of the correction data is shortened by expressing the difference as. That is, in this calculation method, the correction process is performed using equation (22).

The fuse memory may store the values of the correction data D1, D2, D4 to D8, D10. Here, since there is a high probability that the values of these correction data both take a small value, each data length can be reduced to 4 bits. As a result, the total amount of the eight correction data D1, D2, D4 to D8, and D10 can be reduced to 32 bits.
[Calculation method H]
In this calculation method, correction processing is performed using equation (23).

  According to this calculation method, the correction data to be used is reduced to two of D4 and D10 as described in the calculation method F, and D4 and D10 are set to the reference value (for example, “1”) as described in the calculation method G. As a difference value, the data length is shortened to 4 bits. As a result, the total amount of correction data D4 and D10 to be stored is reduced to 8 bits.

Next explained is the third embodiment of the invention. The third embodiment shows an application example in which the geomagnetism detection LSI of FIG. 1 is mounted on a portable device such as a cellular phone.
FIG. 3 is a block diagram showing an outline of the configuration of the mobile phone according to the third embodiment. Note that the geomagnetic detection LSI 210 mounted on the mobile phone 100 of FIG. 3 includes the temperature of the magnetic sensor in addition to the magnetic sensor shown in FIG. 1 (three-axis magnetic sensors orthogonal to each other as in the second embodiment). A temperature sensor is provided for compensation.

  In FIG. 3, the mobile phone 100 is configured to include two housings of a terminal unit 200 and a terminal unit 300. The antenna 235a is an antenna for transmitting / receiving radio wave signals to / from a radio base station (not shown). An RF (Radio Frequency) unit 201 converts a received signal received by the antenna 235a into a received signal having an intermediate frequency and outputs the received signal to the modem unit 202. The RF unit 201 modulates the transmission signal input from the modulation / demodulation unit 202 into a signal having a transmission frequency, and outputs the signal to the antenna 235a for transmission.

  The modem unit 202 performs demodulation processing of the received signal input from the RF unit 201 and modulation processing of the transmission signal input from the CDMA (Code Division Multiple Access) unit 204. The CDMA unit 204 performs transmission signal encoding processing and reception signal decoding processing. The audio processing unit 205 converts the audio signal input from the microphone 206 into a digital signal and outputs the digital signal to the CDMA unit 204. Also, the audio processing unit 205 inputs the digital audio signal from the CDMA unit 204 and converts it into an analog audio signal. Output to the speaker 301 to generate sound. The GPS receiving unit 207 demodulates the radio signal received by the antenna 235b from the GPS satellite, and calculates a position represented by latitude, longitude, altitude, etc. in its own three-dimensional space based on the radio signal.

  The physical quantity sensor 231 detects the inclination of the mobile terminal 100. Further, the mobile terminal 100 does not necessarily include the physical quantity sensor 231. The geomagnetism detection LSI 210 includes magnetic sensors 212a to 212c that detect magnetism (magnetic fields) in predetermined axial directions orthogonal to each other, a temperature sensor 213 that detects temperature, and FIG. Are provided with a magnetic sensor control unit 211 having functions 7 to 9 and 12 to 15. Further, the magnetic sensor control unit 211 performs processing such as analog / digital conversion on the detection results of the temperature sensor 213 and the physical quantity sensor 231.

  The main control unit 220 is a CPU (Central Processing Unit) that controls each unit of the mobile terminal 100. A ROM (Read Only Memory) 208 stores display image data, audio data, a program executed by the main control unit 220, initial characteristic values of the temperature sensor 213 and the physical quantity sensor unit 231 measured at the time of shipping inspection, and the like. A RAM (Random Access Memory) 209 is a non-volatile storage area that temporarily stores calculation data and the like used by the main control unit 220.

  The notification unit 232 includes a speaker, a vibrator, and a light emitting diode, and notifies the user of an incoming call or mail reception by sound, vibration, and light. The clock unit 233 is a time measuring function used by the main control unit 220. The main operation unit 234 outputs the user instruction content to the main control unit 220. The electronic imaging unit 302 converts the subject image into a digital signal and outputs the digital signal to the main control unit 220.

    A display unit 303 is a liquid crystal display that displays images, characters, and the like based on display signals input from the main control unit. The touch panel 304 is incorporated in the surface of the liquid crystal display of the display unit 303, and outputs a signal representing the operation content when the user presses the main control unit 220.

  The geomagnetism detection LSI according to the first and second embodiments takes a form in which correction data is measured by shipping inspection and written in a non-volatile memory mounted on the LSI. Since such a geomagnetism detection LSI is mounted on a portable device, a configuration in which the geomagnetism detection LSI is mounted on a portable device and correction data is written at the time of shipping inspection of the portable device, not at the time of shipment of the geomagnetism detection LSI. It is also possible to take.

  In addition, the correction data measured in the inspection at the time of shipment of the geomagnetism detection LSI is written in the fuse memory inside the LSI, and after the geomagnetic sensor LSI is mounted on the portable device, the geomagnetic sensor LSI measured again at the shipment inspection of the portable device. It is also possible to write the correction data in the memory of the portable device (for example, the ROM 208 in FIG. 3). Thereafter, when detecting the geomagnetism, not only the output result of the geomagnetic sensor LSI but also another correction value (for example, the correction value based on the detection result of the temperature sensor or the physical quantity sensor in FIG. 3) may be applied. Good.

  The embodiment of the present invention has been described in detail above, but the specific configuration is not limited to this embodiment, and includes a design and the like within a range not departing from the gist of the present invention.

  For example, the present invention is not limited to a form using a fuse memory, and may take a form using an antifuse memory, for example.

1 is a block diagram showing an outline of a configuration of a geomagnetic detection LSI according to a first embodiment of the present invention. It is a block diagram which shows the structural example of a fuse memory. It is a block diagram which shows the outline of a structure of the mobile telephone which concerns on 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... LSI 2 ... Power supply terminal 3 ... Ground terminal 4 ... Chip select input terminal 5 ... Data input terminal 6 ... Data output terminal 7 ... Interface circuit 8 ... Control circuit (correction arithmetic circuit) 9 ... Internal transmission circuit 10 ... X-axis direction Magnetic sensor (geomagnetic detection element) 11 ... Y-axis magnetic sensor (geomagnetic detection element) 12 ... Switching circuit 13 ... Amplifier 14 ... A / D conversion circuit 15 ... Fuse memory (thermal deformation non-volatile storage element) 21 Fuse 22 FET 23 Data flip-flop 24 NOR gate 25 Logic gate 100 Mobile phone 210 Geomagnetic detection LSI

Claims (13)

A geomagnetism detecting element for detecting the orthogonal axis component of the geomagnetism,
A geomagnetism detecting device comprising a thermally deformable nonvolatile memory element that stores correction information for correcting the detection output of the geomagnetism detecting element as a coefficient ,
The correction information is
A geomagnetic detection device, characterized in that it is a shaft sensitivity correction coefficient and an inter-axis correction coefficient, and is a value expressed as a ratio to the shaft sensitivity correction coefficient of any axis. The geomagnetic detection device according to claim 1,
The nonvolatile memory element does not store the axial sensitivity correction coefficient of said either axis
A geomagnetic detection device characterized by the above. In the geomagnetism detecting device according to claim 2,
As correction information related to the stored axis sensitivity correction coefficient,
A geomagnetism detection device using a difference value obtained by subtracting a preset reference value from a ratio between the axis sensitivity correction coefficient and one of the axis sensitivity correction coefficients. In the geomagnetism detecting device according to claim 1 to 3,
A correction operation circuit for performing a correction operation of the detection output of the geomagnetism detection element;
This correction arithmetic circuit
A correction term obtained by multiplying the detection output of one axis by the axis sensitivity correction coefficient ;
Geomagnetism detection device which is characterized in that calculates a correction value of the detection output by summing the correction term obtained by multiplying the inter-axis correction coefficient on the detection output of the other axis. In the geomagnetism detecting device according to claim 3 ,
A correction operation circuit for performing a correction operation of the detection output of the geomagnetism detection element;
The correction calculation circuit performs a correction calculation after adding the reference value to the difference value to restore an axis sensitivity correction coefficient. In the geomagnetism detection device according to claim 4 or 5,
The correction calculation circuit performs calculation by substituting a preset substitute value for a correction coefficient that cannot be acquired from the correction information. A geomagnetism detecting element for detecting geomagnetism for each orthogonal axis component;
A geomagnetism detection device comprising: a heat-variable non-volatile storage element that stores one or a plurality of correction data for correcting the detected geomagnetism value as a coefficient ;
Each of the correction data is
The ratio of the axis sensitivity correction coefficient to the axis sensitivity correction coefficient of any axis,
The ratio between the correction factor between axes and the sensitivity correction factor of any axis,
The ratio between the value obtained by subtracting the specified reference value from the axis sensitivity correction coefficient and the axis sensitivity correction coefficient for either axis
A geomagnetic detection device characterized by being represented by any of the following ratios . The geomagnetism detecting device according to claim 7,
At least one of the correction data is a value of a ratio of an axis sensitivity correction coefficient other than one of the axes to an axis sensitivity correction coefficient of any of the axes. The geomagnetism detecting device according to claim 7,
At least one of the correction data is
A geomagnetism detection device, characterized in that the value is a ratio between a difference value obtained by subtracting a predetermined reference value from an axis sensitivity correction coefficient other than one of the axes and an axis sensitivity correction coefficient of any of the axes. The geomagnetism detecting device according to claim 7,
A correction arithmetic circuit for correcting the value of geomagnetism for each orthogonal axis component detected by the geomagnetism detection element;
The correction arithmetic circuit is
Detection output value of one axis component ,
A ratio between the one axis sensitivity correction coefficient and the axis sensitivity correction coefficient of any axis;
Alternatively, a value obtained by subtracting a predetermined reference value from the axis sensitivity correction coefficient and a value obtained by adding 1 to the ratio of the axis sensitivity correction coefficient of any axis, and a multiplied value,
Detection output values of other axis components ,
A ratio between the inter-axis correction coefficient and the axial sensitivity correction coefficient of any one of the axial components;
By calculating the sum of the product multiplied by <br/>
A geomagnetism detecting device characterized by obtaining a corrected geomagnetism value. The geomagnetism detecting device according to claim 7,
A correction arithmetic circuit for correcting the value of geomagnetism for each orthogonal axis component detected by the geomagnetism detection element;
The correction arithmetic circuit is
Detection output value of one axis component ,
A ratio between the one axis sensitivity correction coefficient and the axis sensitivity correction coefficient of any axis;
Alternatively, by calculating a multiplication value obtained by multiplying the ratio of the value obtained by subtracting a predetermined reference value from the axis sensitivity correction coefficient to the ratio of the axis sensitivity correction coefficient of any axis by 1 and
A geomagnetism detecting device characterized by obtaining a corrected geomagnetism value. The geomagnetism detecting device according to claim 7,
The geomagnetic detection device, wherein the thermally deformable non-volatile memory element is a fuse memory. The geomagnetism detecting device according to claim 7,
The predetermined reference value is an axis sensitivity correction coefficient for any one of the axes.

Images