JP2019060734A - Control circuit, physical quantity detector, inertia measurement device, mobile body positioning device, portable electronic apparatus, electronic device, and mobile body - Google Patents

Abstract

To provide a control circuit that can reduce the offset of a physical quantity signal.SOLUTION: The present invention relates to a control circuit for controlling the operation of a physical quantity detection element, which outputs a detection signal from a detection electrode. The control circuit includes; a first regulator for generating a first voltage; a second regulator for generating a second voltage; a driving signal generating circuit for generating a first driving signal with an amplitude corresponding to the first voltage and a second driving signal with an amplitude corresponding to the second voltage, the first and second driving signals having opposite phases, outputting the first driving signal to the first driving electrode of the physical quantity detection element, outputting the second driving signal to the second driving electrode of the physical quantity detection element; and a detection circuit for generating a physical quantity signal with a magnitude corresponding to the amplitude of the detection signal on the basis of the detection signal, the first voltage and the second voltage being variable.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control circuit, a physical quantity detection device, an inertial measurement device, a mobile object positioning device, a portable electronic device, an electronic device, and a mobile object.

  In recent years, the static quantity is detected by utilizing the fact that the capacitance value of the capacitance generated between opposing electrodes provided in the physical quantity detection element changes in accordance with the magnitude and direction of the physical quantity (such as acceleration or angular velocity). Capacitance type physical quantity detection devices (physical quantity sensors) have been developed. For example, a capacitance-type acceleration detection apparatus (acceleration sensor) and an angular velocity detection apparatus (angular velocity sensor) using silicon MEMS (Micro Electro Mechanical System) technology are widely known. As a capacitance type physical quantity detection device, when a physical quantity is added, the capacitance value of one of the two paired capacitances increases and the other capacitance value decreases, and the difference between the two capacitance values It is known that the detection sensitivity of the physical quantity is improved by detecting the amount of charge moved accordingly. However, in such a physical quantity detection device, due to a manufacturing error of the physical quantity detection element, a slight difference occurs between the capacitance values of the two capacitances, and as a result, an offset occurs in the physical quantity signal to be output. It occurs.

  On the other hand, in Patent Document 1, the amplitude of the first drive signal applied to one end of one electrostatic capacitance element of the acceleration sensor is fixed, and the other end of the other electrostatic capacitance element is an inverting amplification circuit A method is disclosed in which the offset is reduced by applying a second drive signal obtained by inverting and amplifying the first drive signal and changing the amplification factor of this inverting amplifier circuit to adjust the output voltage.

JP, 2006-177895, A

  However, in the method described in Patent Document 1, 1 / f noise generated by the operational amplifier is superimposed on the second drive signal output from the inverting amplifier circuit, so a physical quantity signal is generated by the physical quantity detection device to which this method is applied. The S / N ratio (Signal to Noise Ratio) may decrease.

  The present invention has been made in view of the above problems, and provides a control circuit and a physical quantity detection device capable of reducing the offset of the physical quantity signal according to some aspects of the present invention. be able to. Further, according to some aspects of the present invention, it is possible to provide an inertial measurement device capable of improving the accuracy of inertial data transmitted to the outside by using the physical quantity detection device. Further, according to some aspects of the present invention, it is possible to provide a mobile positioning device capable of measuring the position of a mobile with high accuracy by using the inertial measurement device. Further, according to some aspects of the present invention, a portable electronic device, an electronic device, and a movable body capable of performing processing based on a detected physical quantity with high accuracy by using the physical quantity detection device are provided. can do.

  The present invention has been made to solve at least a part of the above-described problems, and can be realized as the following aspects or application examples.

Application Example 1
The control circuit according to the application example includes: a first detection capacitor; a second detection capacitor; a detection electrode electrically connected to one end of the first detection capacitor and one end of the second detection capacitor; And a second drive electrode electrically connected to the other end of the second detection capacitor, wherein a detection signal is output from the detection electrode. A control circuit for controlling the operation of the physical quantity detection element to output, the first regulator generating the first voltage, the second regulator generating the second voltage, and the first drive of the amplitude according to the first voltage Generating a signal and a second drive signal having an opposite phase to the first drive signal and having an amplitude according to the second voltage, and outputting the first drive signal to the first drive electrode of the physical quantity detection element The second drive signal to the second drive electrode of the physical quantity detection element The first voltage and the second voltage include: a driving signal generation circuit, and a detection circuit that generates a physical quantity signal having a magnitude according to the amplitude of the detection signal based on the detection signal; It is variable.

  In this application example, in the physical quantity detection element, the value of the first current flowing between the first drive electrode and the detection electrode via the first detection capacitance is the voltage value of the first drive signal and the capacitance of the first detection capacitance. The value of the second current flowing between the second drive electrode and the detection electrode via the second detection capacitance is determined by the voltage value of the second drive signal and the capacitance value of the second detection capacitance. And since the first voltage is variable, the amplitude of the first drive signal according to the first voltage is also variable, and since the second voltage is variable, the amplitude of the second drive signal according to the second voltage is also variable. is there. Therefore, even if there is a difference between the capacitance value of the first detection capacitance and the capacitance value of the second detection capacitance when no physical quantity is applied to the physical quantity detection element, the first voltage and the second voltage are set to appropriate values. By setting, the difference between the average value of the first current and the average value of the second current becomes smaller, and the average value of the detection signal output from the detection electrode as the difference between the first current and the second current is made zero. It can be approached. Therefore, according to the control circuit according to this application example, since the average value of the detection signal output from the detection electrode is close to zero when no physical quantity is added, the offset of the physical quantity signal generated based on the detection signal is It can be reduced.

  In contrast to the method described in Patent Document 1 in which 1 / f noise generated by the operational amplifier of the inverting amplification circuit is superimposed on the second drive signal, in this application example, the first voltage is generated by the first regulator. Because the noise is small and the second voltage is generated by the second regulator, the noise is small, so both the first drive signal and the second drive signal are low noise. Therefore, according to the control circuit according to this application example, the S / N ratio of the detection signal is improved compared to that of the prior art, so the S / N ratio of the physical quantity signal generated based on the detection signal is improved.

  Furthermore, according to the control circuit according to the application example, since the amplitude of the first drive signal and the amplitude of the second drive signal can be set respectively, the amplitude of the first drive signal and the amplitude of the second drive signal can be set. By setting the value to a large value in the range in which the offset of the physical quantity signal is reduced, the amplitude of the detection signal becomes large, and the S / N ratio of the physical quantity signal can be improved.

Application Example 2
In the control circuit according to the application example, at least one of the first voltage and the second voltage may be a maximum value of a variable range.

  According to the control circuit according to the application example, at least one of the first voltage and the second voltage is the maximum value of the variable range, the amplitude of the first drive signal and the amplitude of the second drive signal are of the physical quantity signal. Since the value is set as large as possible in the range in which the offset is reduced, the amplitude of the detection signal becomes larger, and the S / N ratio of the physical quantity signal can be further improved.

Application Example 3
In the control circuit according to the application example, the first regulator generates the first voltage based on a first reference voltage obtained by resistance division, and the second regulator is obtained by resistance division. The second voltage may be generated based on the second reference voltage.

  In the control circuit according to this application example, the deviation of the resistance ratio from the design value is small even if the resistance value of each resistor becomes uniformly larger than the design value due to manufacturing variation. Therefore, the deviation from the design value of the first reference voltage and the second reference voltage determined by the resistance ratio is also small. Therefore, according to the control circuit according to the application example, the deviation from the design value of the second voltage generated based on the first voltage and the second reference voltage generated based on the first reference voltage is also reduced. The yield is improved, which is advantageous for cost reduction.

Application Example 4
A physical quantity detection device according to this application example includes any one of the control circuits described above and the physical quantity detection element.

  According to the physical quantity detection device according to the application example, by setting the first voltage and the second voltage to appropriate values, the detection signal output from the detection electrode of the physical quantity detection element when the physical quantity is not applied Since the average value can be close to zero, the offset of the physical quantity signal generated based on the detection signal can be reduced.

  Further, according to the physical quantity detection device according to the application example, the first voltage is generated by the first regulator, so the noise is small, and the second voltage is generated by the second regulator, so the noise is small. Since both the signal and the second drive signal have low noise, as a result, the S / N ratio of the detection signal is improved, so the S / N ratio of the physical quantity signal generated based on the detection signal is improved.

  Furthermore, according to the physical quantity detection device according to this application example, since the amplitude of the first drive signal and the amplitude of the second drive signal can be set respectively, the amplitude of the first drive signal and the amplitude of the second drive signal can be set. The amplitude of the detection signal can be increased and the S / N ratio of the physical quantity signal can be improved by setting the value of L to a large value in the range in which the offset of the physical quantity signal is reduced.

Application Example 5
An inertial measurement device according to this application example includes the above-described physical quantity detection device, a signal processing circuit that acquires the physical quantity signal output from the physical quantity detection device, and processes the physical quantity signal, and processing of the signal processing circuit. And a communication circuit for transmitting the obtained inertial data to the outside.

  According to the inertial measurement device according to the application example, since the offset of the physical quantity signal is reduced by the physical quantity detection device, it is possible to improve the accuracy of the inertial data transmitted to the outside.

Application Example 6
The mobile positioning device according to this application example is a mobile positioning device mounted on a mobile and measuring the position of the mobile, and receives satellite signals from the above inertial measurement device and the positioning satellite, The satellite signal reception unit that acquires positioning information superimposed on the satellite signal, the position calculation unit that calculates the position of the moving object based on the positioning information, and the output from the inertial measurement device And a position correction unit that corrects the position on the basis of the posture.

  According to the mobile object positioning device according to the application example, since inertial data with high accuracy can be obtained by the inertial measurement device, the position of the mobile object can be measured with high accuracy.

Application Example 7
A portable electronic device according to this application example includes the physical quantity detection device described above, a case in which the physical quantity detection device is accommodated, and a processing unit which is accommodated in the case and processes output data from the physical quantity detection device. And a display unit accommodated in the case, and a translucent cover closing an opening of the case.

  According to the portable electronic device according to the application example, the offset of the physical quantity signal is reduced by the physical quantity detection device, so that processing based on the physical quantity detected by the physical quantity detection device can be performed with high accuracy.

Application Example 8
An electronic device according to this application example includes the above-described physical quantity detection device, and an arithmetic processing unit that performs arithmetic processing based on the physical quantity signal output from the physical quantity detection device.

  According to the electronic device according to the application example, the offset of the physical quantity signal is reduced by the physical quantity detection device, so that the arithmetic processing based on the physical quantity detected by the physical quantity detection device can be performed with high accuracy.

Application Example 9
The moving body according to this application example includes the above-described physical quantity detection device, and an attitude control unit that performs attitude control based on the physical quantity signal output from the physical quantity detection device.

  According to the mobile object of the application example, the offset of the physical quantity signal is reduced by the physical quantity detection device, so attitude control based on the physical quantity detected by the physical quantity detection device can be performed with high accuracy.

FIG. 2 is a functional block diagram of the physical quantity detection device of the present embodiment. FIG. 2 is a view showing an example of the structure of a physical quantity detection element. FIG. 7 is a diagram for explaining the operation of the physical quantity detection element. FIG. 2 is a diagram showing a specific configuration example of a drive circuit. FIG. 7 shows signal waveforms in the drive circuit. BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the structural example of the inertial measurement device of this embodiment. BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the structural example of the mobile positioning device of this embodiment. FIG. 2 is a functional block diagram of the electronic device of the embodiment. The figure which shows an example of the external appearance of the smart phone which is an example of an electronic device. FIG. 1 is a diagram showing an example of the appearance of a wrist-worn portable device as an example of an electronic device. The figure which shows an example of the external appearance of the wrist device (watch-type activity meter) which is an example of an electronic device. Functional block diagram of wrist device (watch-type activity meter). BRIEF DESCRIPTION OF THE DRAWINGS The perspective view which shows an example of the mobile body of this embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unduly limit the contents of the present invention described in the claims. In addition, not all of the configurations described below are necessarily essential configuration requirements of the present invention.

  In the following, a physical quantity detection device (acceleration detection device) that detects acceleration as a physical quantity will be described as an example.

1. Physical quantity detection device [Configuration and operation of physical quantity detection device]
FIG. 1 is a functional block diagram of the physical quantity detection device of this embodiment. The physical quantity detection device 1 of the present embodiment includes a physical quantity detection element 2 and a control circuit 3.

  The physical quantity detection element is an element that outputs an analog signal (detection signal) according to the physical quantity (here, acceleration) applied in a predetermined direction. The physical quantity detection element 2 includes a first detection capacitance, a second detection capacitance, a detection electrode electrically connected to one end of the first detection capacitance and one end of the second detection capacitance, and the other end of the first detection capacitance It has a first drive electrode electrically connected and a second drive electrode electrically connected to the other end of the second detection capacitor, and a detection signal is output from the detection electrode.

  FIG. 2 is a view (plan view) showing an example of the structure of such a physical quantity detection element 2. As shown in FIG. 2, the physical quantity detection element 2 has a fixed part 200 and a movable part 210. The fixing unit 200 is a member fixed to a substrate (not shown). The movable portion 210 is a structure that is displaced according to acceleration, and includes a weight portion 211 and a spring portion 212. One end of the spring portion 212 is fixed to the substrate, and the other end is connected to the weight portion 211. The weight portion 211 is supported by a spring portion 212.

  As shown in FIG. 3, when an acceleration a is applied to the physical quantity detection element 2, a force F of F = ma acts on the weight section 211 of mass m. The spring portion 212 is deformed by the force F, and the weight portion 211 is displaced relative to the fixing portion 200.

  The weight portion 211 has a movable electrode 211A and a movable electrode 211B. The fixing unit 200 includes fixed electrodes 201 to 204. The movable electrode 211A is disposed between the fixed electrodes 201 and 202, and the movable electrode 211B is disposed between the fixed electrodes 203 and 204. The physical quantity detection element 2 is formed of, for example, a semiconductor material such as Si (silicon) and MEMS (Micro Electro Mechanical Systems) using a semiconductor processing technology.

  Here, the pair of the movable electrode 211A and the fixed electrode 201 and the pair of the movable electrode 211B and the fixed electrode 203 are referred to as a first capacitance forming portion 5. Similarly, the pair of the movable electrode 211A and the fixed electrode 202 and the pair of the movable electrode 211B and the fixed electrode 204 are referred to as a second capacitance forming portion 6. The physical quantity detection element 2 has a terminal 9 connected in common to one end of the first capacitance forming part 5 and one end of the second capacitance forming part 6 and a terminal connected to the other end of the first capacitance forming part 5 And a terminal 8 connected to the other end of the second capacitance forming portion 6. When the acceleration a (force F) shown in FIG. 3 acts, the capacitance value of the first capacitance forming portion 5 decreases while the capacitance value of the second capacitance forming portion 6 increases. Conversely, when an acceleration a (force F) in the direction opposite to that in FIG. 3 acts, the capacitance value of the first capacitance forming portion 5 increases while the capacitance value of the second capacitance forming portion 6 decreases. Therefore, in the state where driving signals of opposite phase to each other are supplied from the terminals 7 and 8 and charges are supplied to the other end of the first capacitance forming portion 5 and the other end of the second capacitance forming portion 6, acceleration a on the weight portion 211 is performed. Causes one end of the first capacitance forming portion 5 and one end of the second capacitance forming portion 6 to output a charge (AC current) according to the magnitude and direction of the acceleration a through the terminal 9 .

  In the configuration example of FIG. 1 and FIG. 2, the first capacitance forming portion 5 and the second capacitance forming portion 6 correspond to a first detection capacitance and a second detection capacitance, respectively. The terminal 7, the terminal 8 and the terminal 9 correspond to the first drive electrode, the second drive electrode and the detection electrode, respectively.

  Returning to FIG. 1, the control circuit 3 includes the Q / V amplifier 10, the variable gain amplifier 20, the low pass filter 30, the A / D conversion circuit 40, the digital processing circuit 50, the oscillation circuit 60, the clock generation circuit 70, and the first regulator 80. , A second regulator 90, a drive signal generation circuit 100, an interface circuit 110, and a storage unit 120. Although illustration is omitted, the control circuit 3 operates by being supplied with the high potential side power supply voltage VDD (for example, 3.0 V) and the low potential side power supply voltage VSS (for example, 0 V). The control circuit 3 may be, for example, an integrated circuit (IC) of one chip. Note that the control circuit 3 of the present embodiment may be configured such that some of these elements are omitted or changed, or other elements are added.

  The oscillation circuit 60 outputs a clock signal MCLK. For example, a CR oscillator or a ring oscillator may be used.

  The clock generation circuit 70 generates various clock signals (clock signals DRVCLK, SMPCLK, DSPCLK) based on the clock signal MCLK.

  The first regulator 80 generates a first voltage VOUT1. Further, the second regulator 90 generates a second voltage VOUT2. In the present embodiment, the first voltage VOUT1 and the second voltage VOUT2 are variable in the voltage range of Vmin or more and Vmax or less. Specifically, the first regulator 80 outputs the first voltage VOUT1 based on the first voltage selection information SEL1 stored in advance in the storage unit 120. Similarly, the first regulator 80 outputs the second voltage VOUT2 based on the second voltage selection information SEL2 stored in advance in the storage unit 120.

  The drive signal generation circuit 100 generates a first drive signal DRV1 and a second drive signal DRV2 for driving the physical quantity detection element 2 based on the first voltage VOUT1 and the second voltage VOUT2 and the clock signal DRVCLK. Then, the drive signal generation circuit 100 outputs the first drive signal DRV1 to the terminal 7 of the physical quantity detection element 2 and outputs the second drive signal DRV2 to the terminal 8 of the physical quantity detection element 2. Here, the first drive signal DRV1 is a signal having an amplitude corresponding to the first voltage VOUT1, and the second drive signal DRV2 has a phase opposite to that of the first drive signal DRV1 and an amplitude corresponding to the second voltage VOUT2. It is a signal. For example, the first drive signal DRV1 may be a rectangular wave signal which becomes the first voltage VOUT1 when the clock signal DRVCLK is at high level and becomes the power supply voltage VSS when the clock signal DRVCLK is at low level. The second drive signal DRV2 may be a rectangular wave signal which becomes the second voltage VOUT2 when the clock signal DRVCLK is at low level and becomes the power supply voltage VSS when the clock signal DRVCLK is at high level.

  As described above, the first regulator 80, the second regulator 90, and the drive signal generation circuit 100 constitute a drive circuit 160 that generates the first drive signal DRV1 and the second drive signal DRV2 for driving the physical quantity detection element 2. The first drive signal DRV1 is a signal of amplitude according to the first voltage selection information SEL1, and the second drive signal DRV2 is a signal of amplitude according to the second voltage selection information SEL2.

  The Q / V amplifier 10 converts the alternating current (detection signal SO) output from the terminal 9 of the physical quantity detection element 2 into an alternating voltage signal QO and outputs it.

  The variable gain amplifier 20 outputs an AC voltage signal PO obtained by amplifying the AC voltage signal QO output from the Q / V amplifier 10.

  The low pass filter 30 outputs an AC voltage signal LO obtained by attenuating a noise component higher in frequency than the frequency band of detectable acceleration with respect to the AC voltage signal PO output from the variable gain amplifier 20.

  The A / D conversion circuit 40 samples the AC voltage signal LO output from the low pass filter 30 based on the clock signal SMPCLK and converts it into a digital signal.

  The digital processing circuit 50 performs, for the digital signal output from the A / D conversion circuit 40, low-pass filter processing for attenuating high frequency noise components, correction processing (for example, temperature correction), and the like. The digital signal (acceleration data) (an example of the “physical quantity signal”) processed by the digital processing circuit 50 is a signal having a magnitude corresponding to the amplitude of the detection signal SO output from the terminal 9 of the physical quantity detection element 2.

  As described above, the Q / V amplifier 10, the variable gain amplifier 20, the low pass filter 30, the A / D conversion circuit 40, and the digital processing circuit 50 generate the detection signal SO output from the terminal 9 of the physical quantity detection element 2. The detection circuit 150 is configured to generate a physical quantity signal (acceleration data) having a magnitude corresponding to the amplitude of the detection signal SO.

The interface circuit 110 is a circuit for communicating with an external device of the physical quantity detection device 1. The external device can write and read data to and from the storage unit 120 via the interface circuit 110, read a digital signal (acceleration data) output from the digital processing circuit 50, and the like. The interface circuit 110 may be, for example, a three-terminal or four-terminal SPI (Serial Peripheral Interface) interface circuit or a two-terminal I ² C (Inter-Integrated Circuit) interface circuit.

  The storage unit 120 includes a register 121 and a non-volatile memory 122. In the non-volatile memory 122, various data (for example, gain adjustment data of the variable gain amplifier 20, filter coefficients of low pass filter processing (digital filter processing) by the digital processing circuit 50) for each circuit included in the control circuit 3 Various types of information are stored. The nonvolatile memory 122 can be configured, for example, as a MONOS (Metal Oxide Nitride Oxide Silicon) type memory or an EEPROM (Electrically Erasable Programmable Read-Only Memory). At power-on of the control circuit 3 (when the power supply voltage rises from 0 V to VDD), various data stored in the non-volatile memory 122 are transferred to and held by the register 121 and held in the register 121. Various data are supplied to each circuit.

[Configuration of drive circuit]
As described above, in the present embodiment, the first drive signal DRV1 is a signal having an amplitude according to the first voltage selection information SEL1, and the second drive signal DRV2 is a signal having an amplitude according to the second voltage selection information SEL2. . FIG. 4 is a diagram showing a specific configuration example of the drive circuit 160 (the first regulator 80, the second regulator 90, and the drive signal generation circuit 100) that generates the first drive signal DRV1 and the second drive signal DRV2. It is.

  In the example of FIG. 4, the first regulator 80 includes a plurality of (N) resistors 81, N−1 switches 82, an operational amplifier 83, and a MOS transistor 84. The N resistors 81 are connected in series to form a series resistor circuit. One end of the series resistor circuit is supplied with a predetermined reference voltage VREF, and the other end is supplied with the power supply voltage VSS. The N-1 switches 82 are respectively connected between respective connection points of the N resistors 81 connected in series and the inverting input terminal of the operational amplifier 83, and according to the first voltage selection information SEL1, One switch 82 is turned on, and the remaining switches 82 are turned off. As a result, the first reference voltage VR1 obtained by voltage division of the N resistors 81 is input to the inverting input terminal of the operational amplifier 83. The noninverting input terminal of the operational amplifier 83 is connected to the drain of the MOS transistor 84, and the output terminal of the operational amplifier 83 is connected to the gate of the MOS transistor 84. The power supply voltage VDD is supplied to the source of the MOS transistor 84, and the first voltage VOUT1 is output from the drain of the MOS transistor 84. Thus, the first regulator 80 generates the first voltage VOUT1 based on the first reference voltage VR1 obtained by the resistance division of the N resistors 81.

  The second regulator 90 includes a plurality of (N) resistors 81, N−1 switches 92, an operational amplifier 93, and a MOS transistor 94. The N resistors 81 are connected in series to form a series resistor circuit. One end of the series resistor circuit is supplied with a predetermined reference voltage VREF, and the other end is supplied with the power supply voltage VSS. That is, the series resistance circuit calibrated by the N resistors 81 is a component of the first regulator 80 and a component of the second regulator 90. The N-1 switches 92 are respectively connected between each connection point of the N resistors 81 connected in series and the inverting input terminal of the operational amplifier 93, and according to the second voltage selection information SEL2, One switch 92 is turned on, and the remaining switches 92 are turned off. As a result, the second reference voltage VR2 obtained by voltage division of the N resistors 81 is input to the inverting input terminal of the operational amplifier 93. The noninverting input terminal of the operational amplifier 93 is connected to the drain of the MOS transistor 94, and the output terminal of the operational amplifier 93 is connected to the gate of the MOS transistor 94. The power supply voltage VDD is supplied to the source of the MOS transistor 94, and the second voltage VOUT2 is output from the drain of the MOS transistor 94. Thus, the second regulator 90 generates the second voltage VOUT2 based on the second reference voltage VR2 obtained by the resistance voltage division of the N resistors 81.

  The drive signal generation circuit 100 includes a switch 101, a switch 102, and a logic inversion circuit 103. The first voltage VOUT1 is input to the first terminal of the switch 101, the power supply voltage VSS is input to the second terminal of the switch 101, and the first drive signal DRV1 is output from the third terminal of the switch 101. When the clock signal DRVCLK is at high level, the first terminal and the third terminal of the switch 101 are conductive, and when the clock signal DRVCLK is at low level, the second terminal and the third terminal of the switch 101 are conductive. The logic inversion circuit 103 outputs a signal obtained by inverting the logic level (high level / low level) of the clock signal DRVCLK. The second voltage VOUT2 is input to the first terminal of the switch 102, the power supply voltage VSS is input to the second terminal of the switch 102, and the second drive signal DRV2 is output from the third terminal of the switch 102. When the output signal of the logic inversion circuit 103 is high level (DRVCLK is low level), the first and third terminals of the switch 102 are conductive, and the output signal of the logic inversion circuit 103 is low level (clock signal DRVCLK is high) At the time of level), the second terminal and the third terminal of the switch 102 are electrically connected.

  FIG. 5 shows the waveforms of the clock signal DRVCLK, the first drive signal DRV1, and the second drive signal DRV2 in the drive circuit 160 having the configuration of FIG. As shown in FIG. 5, the voltage of the first drive signal DRV1 repeats the first voltage VOUT1 and the power supply voltage VSS every half cycle of the clock signal DRVCLK, and the voltage of the second drive signal DRV2 is the power supply voltage VSS and the second Repeat the voltage VOUT2. That is, the first drive signal DRV1 and the second drive signal DRV2 are rectangular wave signals in opposite phase to each other. The amplitude of the first drive signal DRV1 is the voltage of the difference between the first voltage VOUT1 and the power supply voltage VSS, and the amplitude of the second drive signal DRV2 is the voltage of the difference between the second voltage VOUT2 and the power supply voltage VSS.

  In the drive circuit 160 shown in FIG. 4, even if the resistance value of each resistor 81 uniformly becomes larger than the design value due to manufacturing variation, or even if it becomes uniformly smaller, the deviation of the resistance ratio from the design value Is small, the deviation from the design value of the first reference voltage VR1 and the second reference voltage VR2 determined by the resistance ratio is also small. Therefore, the deviation from the design value of the second voltage VOUT2 generated based on the first voltage VOUT1 and the second reference voltage VR2 generated based on the first reference voltage VR1 is also reduced. Since variations in adjustment accuracy of the amplitude of the second drive signal DRV2 are reduced, the yield of the physical quantity detection device 1 is improved, which is advantageous for cost reduction.

[Amplitude adjustment of drive signal]
By the way, due to a manufacturing error of the physical quantity detection element 2, it is difficult to make the capacitance value of the first capacitance forming portion 5 and the capacitance value of the second capacitance forming portion 6 match exactly when at rest (when acceleration is not applied). It is. When there is a difference between the capacitance value of the first capacitance forming portion 5 and the capacitance value of the second capacitance forming portion 6, the physical quantity detection element 2 generates the first drive signal DRV1 and the second drive signal DRV2 of the same amplitude. The average value of the charges charged to the Q / V amplifier 10 at rest does not become zero, and as a result, an offset (zero point offset) occurs in the acceleration data generated by the detection circuit 150.

  Therefore, in the present embodiment, at the time of manufacture of the physical quantity detection device 1 (inspection step), the amplitude of at least one of the first drive signal DRV1 and the second drive signal DRV2 so as to bring the offset closer to zero, ie, the first voltage At least one of VOUT1 and the second voltage VOUT2 is adjusted. Specifically, the physical quantity detection device 1 is operated to read acceleration data in a stationary state, and the capacitance value of the first capacitance formation unit 5 and the second capacitance formation unit 6 are determined depending on whether the offset value is larger or smaller than zero. Calculate which is larger (or smaller) which is the capacity value. Instead of reading out the acceleration data, in the test mode, the AC voltage signal QO output from the Q / V amplifier 10, the AC voltage signal PO output from the variable gain amplifier 20, or the AC voltage signal LO output from the low pass filter 30 It may be configured to be externally monitored, and the difference between these capacitance values may be calculated based on the voltage of the monitored signal. Based on the calculation result, the values of the first voltage selection information SEL1 and the second voltage selection information SEL2 are determined such that the offset value is closest to zero. For example, when the capacitance value of the first capacitance forming portion 5 is larger than the capacitance value of the second capacitance forming portion 6, the first voltage is set such that the first voltage VOUT1 becomes lower than the second voltage VOUT2 according to the difference. The values of the selection information SEL1 and the second voltage selection information SEL2 are determined. In addition, when the capacitance value of the first capacitance formation portion 5 is smaller than the capacitance value of the second capacitance formation portion 6, the first voltage is set such that the first voltage VOUT1 becomes higher than the second voltage VOUT2 according to the difference. The values of the selection information SEL1 and the second voltage selection information SEL2 are determined.

  Here, since noise of constant intensity is superimposed in each circuit included in the detection circuit 150, the larger the amplitude of the detection signal SO, the higher the S / N ratio of the generated acceleration data. Therefore, it is preferable that the amplitude of the first drive signal DRV1 and the amplitude of the second drive signal DRV2 be as large as possible. Therefore, it is preferable to determine the values of the first voltage selection information SEL1 and the second voltage selection information SEL2 such that at least one of the first voltage VOUT1 and the second voltage VOUT2 becomes the maximum value Vmax of the variable range. Specifically, when the capacitance value of the first capacitance forming portion 5 is larger than the capacitance value of the second capacitance forming portion 6, the first voltage VOUT2 is set to the maximum value Vmax according to the difference. It is preferable to determine the values of the voltage selection information SEL1 and the second voltage selection information SEL2. In addition, when the capacitance value of the first capacitance forming portion 5 is smaller than the capacitance value of the second capacitance forming portion 6, the first voltage selection information is set such that the first voltage VOUT1 has the maximum value Vmax according to the difference. It is preferable to determine the values of SEL1 and second voltage selection information SEL2. Further, when the capacitance value of the first capacitance forming portion 5 and the capacitance value of the second capacitance forming portion 6 are equal to each other, the first voltage selection information SEL1 is set so that the first voltage VOUT1 and the second voltage VOUT2 both have the maximum value Vmax. Preferably, the value of the second voltage selection information SEL2 is determined.

  The maximum value Vmax may be the power supply voltage VDD. Further, the minimum value Vmin is set to be equal to or higher than the lower limit voltage for causing the physical quantity detection element 2 to continue the vibration.

[Function effect]
In the physical quantity detection device 1 of the present embodiment described above, in the physical quantity detection element 2, the first capacitance formation portion 5 (first detection capacitance) is provided between the terminal 7 (first drive electrode) and the terminal 9 (detection electrode). The value of the first current that flows through (1) is determined by the voltage value of the first drive signal DRV1 and the capacitance value of the first capacitance forming portion 5. Similarly, the value of the second current flowing between the terminal 8 (second drive electrode) and the terminal 9 (detection electrode) via the second capacitance forming portion 6 (second detection capacitance) is the second drive signal DRV2. And the capacitance value of the second capacitance forming portion 6. Then, in the control circuit 3, since the first voltage VOUT1 is variable, the amplitude of the first drive signal DRV1 according to the first voltage VOUT1 is also variable, and since the second voltage VOUT2 is variable, it is possible to respond to the second voltage VOUT2. The amplitude of the second drive signal is also variable. Therefore, even if there is a difference between the capacitance value of the first capacitance forming portion 5 and the capacitance value of the second capacitance forming portion 6 when no physical quantity (acceleration) is applied to the physical quantity detection element 2, the first voltage selection information By setting the first voltage VOUT1 to an appropriate value by SEL1 and setting the second voltage VOUT2 to an appropriate value by the second voltage selection information SEL2, the average of the first current and the average of the second current can be obtained. The difference is smaller. Therefore, according to the physical quantity detection device 1 (control circuit 3) of the present embodiment, the current output from the terminal 9 as the difference between the first current and the second current when no physical quantity is applied to the physical quantity detection element 2 Since the average value of (detection signal SO) can be brought close to zero, the offset of the acceleration data (physical quantity signal) generated based on the detection signal SO can be reduced.

  Further, in the physical quantity detection device 1 (control circuit 3) of the present embodiment, the first voltage VOUT1 is generated by the first regulator 80, so the noise is small, and the second voltage VOUT2 is generated by the second regulator 90. Therefore, both the first drive signal DRV1 and the second drive signal DRV2 have low noise. Therefore, according to the physical quantity detection device 1 (control circuit 3) of the present embodiment, the S / N ratio of the detection signal SO is improved, so S / S of the acceleration data (physical quantity signal) generated based on the detection signal SO. N ratio improves.

  Furthermore, according to the physical quantity detection device 1 (control circuit 3) of the present embodiment, the amplitude of the first drive signal DRV1 and the amplitude of the second drive signal DRV2 are determined by the first voltage selection information SEL1 and the second voltage selection information SEL2. Can be set independently of each other, by setting the amplitude of the first drive signal DRV1 and the amplitude of the second drive signal DRV2 to large values within the range where the offset of the acceleration data (physical quantity signal) is reduced. The amplitude of the detection signal SO is increased, and the S / N ratio of the acceleration data (physical quantity signal) can be improved. In particular, by setting at least one of the first voltage VOUT1 and the second voltage VOUT2 to the maximum value of the variable range, the amplitude of the detection signal SO is maximized in the range where the offset of the acceleration data (physical quantity signal) is reduced. The S / N ratio of acceleration data (physical quantity signal) can be further improved.

[Modification]
In the above embodiment, the physical quantity signal (acceleration signal) output from the physical quantity detection device 1 is a digital signal, but may be an analog signal.

  Further, although the physical quantity detection device 1 of the above embodiment detects the physical quantity (acceleration) of one axis, it may detect the physical quantities of a plurality of axes (two axes, three axes or four or more axes) intersecting with each other. In the physical quantity detection device 1 of this modification, for example, the physical quantity detection element 2, the drive circuit 160, and the detection circuit 150 may be provided independently for each axis, and a plurality of physical quantities for detecting the physical quantity of each axis. One or both of the drive circuit 160 and the detection circuit 150 may be provided in common to the detection element 2.

  Further, in the above embodiment, the physical quantity detection device 1 (control circuit 3) that detects acceleration as a physical quantity is described as an example, but in the present invention, physical quantity detection that detects various physical quantities such as angular velocity, angular acceleration, and pressure It is applicable also to an apparatus (control circuit).

2. Inertial Measurement Unit (IMU)
FIG. 6 is a view showing a configuration example of the inertial measurement device of the present embodiment. As shown in FIG. 6, the inertial measurement device 400 of this embodiment detects three angular velocities respectively detecting angular velocities of three axes (x-axis, y-axis, z-axis) intersecting (ideally orthogonal) with each other. Detection devices 411 to 413, three acceleration detection devices 421 to 423 for detecting accelerations of three axes (x axis, y axis, z axis) intersecting with each other (ideally orthogonal), signal processing circuit 430, storage A section 440 and a communication circuit 450 are included. In the inertial measurement device 400 of the present embodiment, a part of the components (each part) shown in FIG. 6 may be omitted or changed, or another component may be added.

  The angular velocity detection device 411 detects an angular velocity generated around the x axis, and outputs an angular velocity signal according to the magnitude and direction of the detected x axis angular velocity. The angular velocity detection device 412 detects an angular velocity generated around the y-axis, and outputs an angular velocity signal according to the magnitude and direction of the detected y-axis angular velocity. The angular velocity detection device 413 detects an angular velocity generated around the z-axis, and outputs an angular velocity signal according to the magnitude and direction of the detected z-axis angular velocity.

  The acceleration detection device 421 detects an acceleration generated around the x-axis, and outputs an acceleration signal according to the magnitude and direction of the detected x-axis acceleration. The acceleration detection device 422 detects an acceleration generated around the y-axis, and outputs an acceleration signal according to the magnitude and direction of the detected y-axis acceleration. The acceleration detection device 423 detects an acceleration generated around the z-axis, and outputs an acceleration signal according to the magnitude and direction of the detected z-axis acceleration.

  The three angular velocity detectors 411 to 413 may be housed in one package to constitute a three-axis angular velocity detection module. Similarly, the three acceleration detection devices 421 to 423 may be housed in one package to constitute a three-axis acceleration detection module.

  The signal processing circuit 430 acquires the triaxial angular velocity signals output from the angular velocity detectors 411 to 413, acquires the triaxial acceleration signals output from the acceleration detectors 421 to 423, and acquires the acquired triaxial angular velocity signals and 3 Process the axis acceleration signal. For example, the signal processing circuit 430 sequentially A / D converts the acquired three-axis angular velocity signal and three-axis acceleration signal to generate inertial data including three-axis angular velocity data and three-axis acceleration data, and adds time information A process of storing inertial data in the storage unit 440 is performed. In addition, the signal processing circuit 430 is calculated in advance according to the mounting angular errors (errors between the detection axes and the x-axis, y-axis, and z-axis) of the angular velocity detectors 411 to 413 and the acceleration detectors 421 to 423, respectively. The inertial data stored in the storage unit 440 is converted (corrected) to data of the xyz coordinate system using the correction parameter, and stored in the storage unit 440. In addition, the signal processing circuit 430 reads inertia data stored in the storage unit 440 in the order of time by converting it into data of the xyz coordinate system, generates packet data including time information and inertia data, and outputs the packet data to the communication circuit 450 .

  In addition, the signal processing circuit 430 may perform offset correction processing and temperature correction processing on the inertia data, and the detection operations (for example, detection of each of the angular velocity detection devices 411 to 413 and the acceleration detection devices 421 to 423). The period may be controlled.

  Communication circuit 450 receives packet data (inertial data with time information) obtained by the processing of signal processing circuit 430, converts the packet data into serial data conforming to a predetermined communication format, and outputs the serial data to the outside. Send.

  The three-axis angular velocity signals output from the angular velocity detectors 411 to 413 and the three-axis acceleration signals output from the acceleration detectors 421 to 42 may be digital signals. In addition, although the inertial measurement device 400 of the present embodiment includes three angular velocity detection devices 411 to 413 and three acceleration detection devices 421 to 423, at least one angular velocity detection device may be included.

  In the inertial measurement device 400 of the present embodiment, the physical quantity detection device 1 of each of the above-described embodiments or each modification is applied as at least one of the acceleration detection devices 421 to 423 or at least one of the angular velocity detection devices 411 to 413. Ru. According to the inertial measurement device 400 of the present embodiment, the physical quantity detection device 1 capable of reducing the offset of the physical quantity signal as at least one of the acceleration detection devices 421 to 423 or at least one of the angular velocity detection devices 411 to 413 Can be achieved, so that high measurement accuracy can be achieved.

3. Mobile Positioning Device FIG. 7 is a view showing an example of the configuration of a mobile positioning device according to the present embodiment. As shown in FIG. 7, the mobile body positioning device 500 of this embodiment includes a sensor module 510, a processing unit 520, an operation unit 530, a storage unit 540, a display unit 550, a sound output unit 560, and a communication unit 570. It is configured and mounted on various mobiles. In addition, the mobile body positioning device 500 of the present embodiment may omit or change a part of the components (each part) shown in FIG. 7 or may be configured to be added with other components.

  The sensor module 510 includes an inertial measurement unit 511 and a satellite signal reception unit 512.

  The inertial measurement unit 511 measures three angular velocity detectors (not shown) that respectively detect angular velocities generated around three axes (x-axis, y-axis, z-axis), and around three axes (x-axis, y-axis, z-axis) And three acceleration detection devices (not shown) for detecting the generated acceleration. Then, the sensor module 510 performs predetermined processing (A / D conversion processing, mounting angle for the 3-axis angular velocity signal detected by the three angular velocity detectors and the 3-axis acceleration signal detected by the three acceleration detectors). Perform error correction processing etc.). Furthermore, the sensor module 510 outputs, to the processing unit 520, inertial data (three-axis angular velocity data and three-axis acceleration data) obtained by performing predetermined processing. As the inertial measurement device 511, the inertial measurement device 400 of the above embodiment is applied.

  The satellite signal reception unit 512 receives an navigation message ("Positioning information") including orbit information and time information of the positioning satellite from a positioning satellite such as a GPS (Global Positioning System) satellite via an antenna (not shown). An example is received (radio signal (satellite signal)) superimposed. The satellite signal reception unit 512 receives satellite signals respectively transmitted from, for example, three or more positioning satellites, and demodulates (acquires) a navigation message superimposed on each received satellite signal by, for example, a known technique. , Each navigation message is output to the processing unit 520. Note that the satellite signal reception unit 512 may use satellite signals from positioning satellites for Global Navigation Satellite System (GNSS) other than GPS or satellites for positioning satellites other than GNSS, or WAAS (Wide (Wide) One of the satellite positioning systems, such as Area Augmentation System (EGNOS), European Geostationary-Satellite Navigation Overlay Service (EGNOS), Quasi Zenith Satellite System (QZSS), GLOAS (GLO BalNA vigation Satellite System), GALILEO, BeiDou Navigation Satellite System (GEI). Alternatively, satellite signals from positioning satellites of two or more systems may be used.

  Although the inertial measurement device 511 and the satellite signal reception unit 512 are included in the sensor module 510 in FIG. 7, they may not be integrated as the sensor module 510. That is, the inertial measurement device 511 and the satellite signal reception unit 512 may not be accommodated in one package.

  The operation unit 530 is an input device configured by operation keys, a button switch, and the like, and outputs an operation signal according to an operation by the user to the processing unit 520.

  The storage unit 540 is used as a ROM (Read Only Memory) that stores programs and data for the processing unit 520 to perform various calculation processing and control processing, or as a work area of the processing unit 520, and is read from the ROM. It includes a RAM (Random Access Memory) for temporarily storing the program and data, the data input from the operation unit 530, the calculation result executed by the processing unit 520 according to various programs, and the like.

  The display unit 550 is a display device configured by a liquid crystal display (LCD: Liquid Crystal Display), an organic EL display (OELD: Organic Electro-Luminescence Display), an electrophoretic display or the like, and a display signal input from the processing unit 520 Display various information based on.

  The sound output unit 560 is a device that outputs sound such as a speaker.

  The communication unit 570 performs various controls for establishing data communication between the processing unit 520 and the external device.

  The processing unit 520 performs various calculation processing and control processing according to the program stored in the storage unit 540. Specifically, the processing unit 520 acquires inertial data from the inertial measurement unit 511, acquires a navigation message from the satellite signal reception unit 512, and various data corresponding to the acquired data and the operation signal from the operation unit 530. Processing, processing for controlling the communication unit 570 to perform data communication with an external device, processing for transmitting a display signal for displaying various information on the display unit 550, and causing the sound output unit 560 to output various sounds Perform processing etc.

  In particular, in the present embodiment, the processing unit 520 functions as each unit of the posture calculation unit 521, the position calculation unit 522, and the position correction unit 523 by executing the program stored in the storage unit 540.

  The attitude calculation unit 521 calculates the attitude of the moving object on which the moving object positioning device 500 is mounted, for example, by a known method based on the inertia data output from the inertia measurement device 511.

  The position calculation unit 522 calculates the position of the mobile body based on the navigation message output from the satellite signal reception unit 512. Specifically, the position calculation unit 522 uses the information such as the transmission time of the satellite signal included in the three or more navigation messages output from the satellite signal reception unit 512 and the radio wave propagation delay at the time of reception, etc. The distance between the mobile unit on which the positioning device 500 is mounted and three or more positioning satellites is calculated. Then, the position calculation unit 522 calculates the position of the moving body from the calculated distance.

  The position correction unit 523 corrects the position of the moving body calculated by the position calculation unit 522 based on the posture of the moving body calculated by the posture calculation unit 521. For example, the position correction unit 523 calculates the inclination angle of the movable body with respect to the horizontal plane from the attitude of the movable body, and corrects the position of the movable body in the horizontal plane to the position in the plane where the movable body moves based on the calculated inclination angle. You may

  The processing unit 520 causes the display unit 550 to display information such as the position and orientation of the moving object, or causes the sound output unit 560 to output the information, or transmits the information to an external device via the communication unit 570.

  The satellite signal reception unit 512 receives each satellite signal and demodulates the navigation message, and the position calculation unit 522 calculates the distance between the mobile unit and each positioning satellite using the navigation message, thereby determining the position of the mobile unit. Although calculated, the satellite signal reception unit 512 may calculate the distance between the mobile unit and each positioning satellite, or may calculate the position of the mobile unit. That is, the satellite signal reception unit 512 may perform at least a part of the process performed by the position calculation unit 522.

  According to the mobile object positioning device 500 of the present embodiment, the inertial measurement device 400 capable of achieving high measurement accuracy is applied as the inertial measurement device 511, so, for example, the position, posture, and the like of the mobile object can be further enhanced. It can be measured with high accuracy.

4. Electronic Device FIG. 8 is an example of a functional block diagram of the electronic device of the present embodiment. As shown in FIG. 8, the electronic device 600 of the present embodiment includes a physical quantity detection device 610, an arithmetic processing unit 620, an operation unit 630, a ROM 640, a RAM 650, a communication unit 660, a display unit 670, and a sound output unit 680. It is configured. Note that in the electronic device 600 of the present embodiment, a part of the components (each part) shown in FIG. 8 may be omitted or changed, or another component may be added.

  The physical quantity detection device 610 detects physical quantities generated in one or more axes (two axes, three axes, or four or more axes), and outputs a physical quantity signal to the arithmetic processing unit 620. As the physical quantity detection device 610, the physical quantity detection device 1 of each of the above-described embodiments or each variation is applied.

  The arithmetic processing unit 620 performs various calculation processing and control processing according to a program stored in the ROM 640 or the like. Specifically, the arithmetic processing unit 620 performs arithmetic processing (for example, various kinds of calculation processing, control processing, and the like) based on the physical quantity signal output from the physical quantity detection device 610. Further, the arithmetic processing unit 620 performs various processes according to the operation signal from the operation unit 630, a process of controlling the communication unit 660 to perform data communication with the outside, and causes the display unit 670 to display various information. A process of transmitting display signals, a process of causing the sound output unit 680 to output various sounds, and the like are performed.

  The operation unit 630 is an input device configured by operation keys, a button switch, and the like, and outputs an operation signal according to an operation by a user to the arithmetic processing unit 620.

  The ROM 640 stores programs, data, and the like for the arithmetic processing unit 620 to perform various calculation processes and control processes.

  The RAM 650 is used as a work area of the processing unit 620, and temporarily stores programs and data read from the ROM 640, data input from the operation unit 630, calculation results executed by the processing unit 620 according to various programs, and the like. Remember to

  The communication unit 660 performs various controls for establishing data communication between the arithmetic processing unit 620 and the external device.

  The display unit 670 is a display device including a liquid crystal display (LCD), an organic electro-luminescence (OELD) display, an electrophoretic display, and the like, and a display input from the arithmetic processing unit 620 Display various information based on the signal.

  The sound output unit 680 is a device that outputs sound such as a speaker.

  According to the electronic device 600 of the present embodiment, since the physical quantity detection device 1 capable of reducing the offset of the physical quantity signal is applied as the physical quantity detection device 610, for example, processing based on changes in physical quantity (for example, posture Control) can be performed with higher accuracy.

  Various electronic devices can be considered as the electronic device 600. For example, seismometers, work robots, health monitoring devices, unmanned operation devices, personal computers (eg, mobile personal computers, laptop personal computers, tablet personal computers), mobile terminals such as mobile phones, digital cameras, Ink jet-type ejection devices (eg, inkjet printers), storage area network devices such as routers and switches, local area network devices, devices for mobile terminal base stations, televisions, video cameras, video recorders, car navigation devices, pagers, electronic organizers (Including communication function), electronic dictionary, calculator, electronic game machine, game controller, word processor, work station, videophone, tele for crime prevention Monitors, electronic binoculars, POS (point of sale) terminals, medical devices (such as electronic thermometers, sphygmomanometers, blood glucose meters, electrocardiogram measuring devices, ultrasound diagnostic devices, electronic endoscopes), fish finders, various measuring devices, meters Classes (for example, vehicle, aircraft, ship instruments, etc.), flight simulators, head mounted displays, motion traces, motion tracking, motion controllers, PDR (pedestrian position and orientation measurement) and the like.

  FIG. 9 is a view showing an example of the appearance of a smartphone which is an example of the electronic device 600, and FIG. 10 is a view showing an example of the appearance of a wrist-worn portable device as an example of the electronic device 600. A smartphone as the electronic device 600 shown in FIG. 9 includes a button as the operation unit 630 and an LCD as the display unit 670. The arm-worn portable device as the electronic device 600 shown in FIG. 10 includes a button and a crown as the operation unit 630, and an LCD as the display unit 670. In these electronic devices 600, the physical quantity detection apparatus 1 capable of reducing the offset of the physical quantity signal is applied as the physical quantity detection apparatus 610, so processing based on changes in the physical quantity (for example, display control according to attitude) ) Can be performed with higher accuracy.

  Furthermore, as an example of the electronic device 600, there is a watch-type activity meter (active tracker) which is one of portable electronic devices. A wristwatch-type activity meter is attached to a part (subject) such as a wrist by a band or the like, and has a display unit of digital display and can be wirelessly communicated. The physical quantity detection device 1 according to the present embodiment described above is incorporated in a watch-type activity meter.

  The liquid crystal display (LCD) constituting the display unit 670, according to various detection modes, for example, position information using a GPS or a geomagnetic sensor, movement information such as movement amount or movement amount using an acceleration sensor or angular velocity sensor , Biological information such as a pulse rate using a pulse wave sensor or the like, or time information such as the current time is displayed.

  FIG. 11 is a plan view of a wrist device 800 (watch-type activity meter) according to an embodiment of the portable electronic device 600. As shown in FIG. The wrist device 800 can be widely applied to a running watch, a runner's watch, a multiathletic runner's watch such as a duathlon or a triathlon, an outdoor watch, and a satellite positioning system, for example, a GPS watch equipped with GPS.

  The wrist device 800 can be worn on a given part (for example, the wrist) of a user (wearer), and can detect position information, exercise information and the like of the user. The wrist device is attached to the user and detects the position information, exercise information, etc., and the first band portion 821 and the second band attached to the device body 810 for attaching the device body 810 to the user And 822. The wrist device 800 can be provided with a function of detecting biological information such as pulse wave information and a function of acquiring time information in addition to user's position information and exercise information.

  In the device body 810, a bottom case (not shown) as a case is disposed on the side of attachment to the user, and on the opposite side to the side of attachment to the user, a top case 830 as a case having an opening opening on the front side It is arranged. Here, the bottom case and the top case 830 constitute a case. A bezel 840 is provided on the outer side of the opening located on the front side (top case 830) of the device body 810, and a top plate portion arranged alongside the bezel 840 inside the bezel 840 to protect the internal structure ( A windshield (for example, a glass plate) 850 as an outer wall) is provided. The windshield plate 850 functions as a translucent cover, and is disposed to close the opening of the top case 830. A plurality of operation units 871 (operation buttons) are provided on the side surface of the front side (top case 830) of the device body 810. The bezel 840 can be provided with a display that can be viewed from the front side.

  In addition, the device body 810 is disposed between a display unit 874 configured by a liquid crystal display (LCD) or the like disposed immediately below the windshield 850, and an outer edge portion of the windshield 850 and the display unit 874. A moisture absorbing member 860 is included, and the display 874 and the moisture absorbing member 860 are accommodated in a case. Note that the hygroscopic member 860 can be provided with a display that can be viewed from the front side. The device body 810 may be configured such that the display on the display unit 874 and the display on the moisture absorption member 860 can be viewed by the user via the windshield 850. That is, in the wrist device 800 according to the present embodiment, various information such as detected position information, exercise information, or time information is displayed on the display unit 874, and the display is presented to the user from the top side of the device body 810. It may be. Further, on both sides of the bottom case, a pair of band attachment parts (not shown) which are connection parts with the first band part 821 and the second band part 822 are provided.

  FIG. 12 is an example of a functional block diagram of the wrist device 800. As shown in FIG. 12, the wrist device 800 includes a processing unit 870, a GPS sensor 880, a geomagnetic sensor 881, a pressure sensor 882, an acceleration sensor 883, an angular velocity sensor 884, a pulse sensor 885, a temperature sensor 886, an operation unit 871, a clock unit. A storage unit 873, a display unit 874, a sound output unit 875, a communication unit 876, a battery 877, and the like are included, and these units are accommodated in the case. However, the configuration of the wrist device 800 may be a configuration in which some of these components are deleted or changed, or other components are added.

  The communication unit 876 performs various controls for establishing communication between the wrist device 800 and another information terminal. The communication unit 876 is, for example, Bluetooth (registered trademark) (BTLE: includes Bluetooth Low Energy), Wi-Fi (registered trademark) (Wireless Fidelity), Zigbee (registered trademark), NFC (Near field communication), ANT + (registered trademark) A transceiver corresponding to the short distance wireless communication standard such as a trademark) and the communication unit 876 include a connector corresponding to the communication bus standard such as USB (Universal Serial Bus).

  The processing unit 870 (processor) is configured by, for example, a micro processing unit (MPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), or the like. The processing unit 870 executes various types of processing based on the program stored in the storage unit 873 and the signal input from the operation unit 871. For processing by the processing unit 870, data processing for each output signal (output data) of the GPS sensor 880, geomagnetic sensor 881, pressure sensor 882, acceleration sensor 883, angular velocity sensor 884, pulse sensor 885, temperature sensor 886, and time measuring unit 872 Display processing for displaying an image on the display unit 874, sound output processing for outputting sound to the sound output unit 875, communication processing for communicating with an information terminal through the communication unit 876, and power from the battery 877 to each unit Power control processing and the like are included.

  The processing unit 870 measures the total distance traveled by the user from the start of measurement using the high precision GPS function. Further, the processing unit 870 measures and displays the current traveling pace of the user from the result of the distance measurement. The processing unit 870 also calculates and displays the average speed from the start of travel of the user to the present time. Further, the processing unit 870 measures and displays the altitude by the GPS function. The processing unit 870 also measures and displays the stride of the user even in a tunnel or the like to which GPS radio waves do not reach. Further, the processing unit 870 measures and displays the number of steps (pitch) per minute of the user. Further, the processing unit 870 measures and displays the heart rate of the user by the pulse sensor. Further, the processing unit 870 measures and displays the slope of the ground in training or trail running in the mountain area of the user. Also, the processing unit 870 automatically performs lap measurement (auto lap) when running a predetermined distance or a predetermined time set in advance. Further, the processing unit 870 displays the consumed calories of the user. The processing unit 870 also displays the total number of steps from the start of the user's exercise.

  The acceleration sensor 883 including the physical quantity detection device 1 according to the above embodiment detects accelerations in directions of three axes intersecting (ideally orthogonal) with each other, according to the magnitude and direction of the detected three-axis acceleration. Output an acceleration signal. Alternatively, the angular velocity sensor 884 including the physical quantity detection device 1 according to the above embodiment detects the angular velocity in the directions of three axes intersecting (ideally orthogonal) with each other, and the magnitude and direction of the detected three axial angular velocity Output a signal (angular velocity signal) according to

  In addition, although the wrist device 800 mentioned above uses GPS (Global Positioning System) as a satellite positioning system, you may use another Global Navigation Satellite System (GNSS). For example, one or more of satellite positioning systems such as EGNOS (European Geostationary-Satellite Navigation Overlay Service), QZSS (Quasi Zenith Satellite System), GLONASS (GLObal NA vigation Satellite System), GALILEO, BeiDou (BeiDou Navigation Satellite System), etc. You may use it. In addition, using at least one of the satellite positioning systems, the Satellite-based Augmentation System (SBAS) such as Wide Area Augmentation System (WAAS), European Geostationary-Satellite Navigation Overlay Service (EGNOS), etc. It is also good.

5. Mobile Body FIG. 13 is a perspective view showing the configuration of an automobile which is an example of the mobile body of the present embodiment. As shown in FIG. 13, the physical quantity detection device 1 is mounted on the automobile 1500, and, for example, the physical quantity detection device 1 can detect the posture of the vehicle body 1501. The physical quantity signal output from the physical quantity detection device 1 is supplied to a vehicle body attitude control device 1503 as a control unit (posture control unit) that controls the attitude of the vehicle body, and the vehicle body attitude control device 1502 determines the vehicle body 1501 based on the signal. The posture of the vehicle can be detected, and the hardness of the suspension can be controlled according to the detection result, or the brakes of the individual wheels 1503 can be controlled. In addition, the physical quantity detection device 1 also includes a keyless entry, an immobilizer, a car navigation system, a car air conditioner, an antilock brake system (ABS), an air bag, a tire pressure monitoring system (TPMS: Tire Pressure Monitoring System), It can be widely applied to electronic control units (ECUs) such as engine control, control devices for inertial navigation for autonomous driving, and battery monitors of hybrid vehicles and electric vehicles.

  In addition to the above examples, the physical quantity detection device 1 applied to a mobile object may be, for example, attitude control such as a biped robot or a train, remote control such as a radio controlled airplane, a radio controlled helicopter, or a drone or autonomous type It can be used in attitude control of flight vehicles, attitude control of agricultural machines (agricultural machines) or construction machines (construction machines). As described above, the physical quantity detection device 1 and each control unit (not shown) are incorporated in order to realize attitude control of various moving bodies.

  Since such a mobile includes the physical quantity detection device 1 capable of reducing the offset of the physical quantity signal and the control unit (not shown), control based on changes in physical quantity by the control unit (posture control, etc.) Can be done with high accuracy.

  The present invention is not limited to the present embodiment, and various modifications can be made within the scope of the present invention.

  The above-mentioned embodiment and modification are an example, and are not necessarily limited to these. For example, it is also possible to combine each embodiment and each modification suitably.

  The present invention includes configurations substantially the same as the configurations described in the embodiments (for example, configurations having the same function, method and result, or configurations having the same purpose and effect). Further, the present invention includes a configuration in which a nonessential part of the configuration described in the embodiment is replaced. The present invention also includes configurations that can achieve the same effects as the configurations described in the embodiments or that can achieve the same purpose. Further, the present invention includes a configuration in which a known technology is added to the configuration described in the embodiment.

DESCRIPTION OF SYMBOLS 1 ... Physical quantity detection apparatus, 2 ... Physical quantity detection element, 3 ... Control circuit, 5 ... 1st capacity formation part, 6 ... 2nd capacity formation part, 7, 8, 9, ... terminal, 10 ... Q / V amplifier, 20 ... Variable gain amplifier, 30: low pass filter, 40: A / D conversion circuit, 50: digital processing circuit, 60: oscillation circuit, 70: clock generation circuit, 80: first regulator, 81: resistance, 82: switch, 83: ... Operational amplifier 84: MOS transistor 90: second regulator 92: switch 93: operational amplifier 94: MOS transistor 100: drive signal generation circuit 101: switch 102: switch 103: logic inversion circuit 110 ... interface circuit, 120 ... storage unit, 121 ... register, 122 ... non-volatile memory, 150 ... detection circuit, 160 ... drive circuit 200: fixed portion, 201 to 204: fixed electrode, 210: movable portion, 211: weight portion, 211A, 211B: movable electrode, 212: spring portion, 400: inertia measurement device, 411, 412, 413: angular velocity detection device, 421, 422, 423 acceleration detection device 430 signal processing circuit 440 storage unit 450 communication circuit 500 mobile body positioning device 510 sensor module 520 processing unit 521 attitude calculation unit 522 ... Position calculation unit, 523 ... Position correction unit, 530 ... Operation unit, 540 ... Storage unit, 550 ... Display unit, 560 ... Sound output unit, 570 ... Communication unit, 600 ... Electronic equipment, 610 ... Physical quantity detection device, 620 ... Arithmetic processing unit, 630 ... operation unit, 640 ... ROM, 650 ... RAM, 660 ... communication unit, 670 ... display unit, 680 ... sound output unit, 800 ... wrist unit , 810: device body, 821: first band portion, 822: second band portion, 830: top case, 840: bezel, 850: windshield, 860: moisture absorbing member, 870: processing portion, 880: GPS sensor , 881: geomagnetic sensor, 882: pressure sensor, 883: acceleration sensor, 884: angular velocity sensor, 885: pulse sensor, 886: temperature sensor, 871: operation unit, 872: timer unit, 873: storage unit, 874: display unit 875 Sound output unit 876 Communication unit 877 Battery 1500 Car 1501 Car body 1502 Car body attitude control device 1503 Wheels

Claims (9)

A first detection capacitor, a second detection capacitor, a detection electrode electrically connected to one end of the first detection capacitor and one end of the second detection capacitor, and an other end of the first detection capacitor Control of operation of a physical quantity detection element having a first drive electrode connected and a second drive electrode electrically connected to the other end of the second detection capacitor, and outputting a detection signal from the detection electrode Control circuit, and
A first regulator generating a first voltage;
A second regulator generating a second voltage;
Generating a first drive signal having an amplitude corresponding to the first voltage, and a second drive signal having an opposite phase to the first drive signal and having an amplitude corresponding to the second voltage; A drive signal generation circuit that outputs the first drive electrode of the physical quantity detection element and outputs the second drive signal to the second drive electrode of the physical quantity detection element;
A detection circuit that generates a physical quantity signal having a magnitude corresponding to the amplitude of the detection signal based on the detection signal;
Including
A control circuit, wherein the first voltage and the second voltage are variable. In claim 1,
A control circuit, wherein at least one of the first voltage and the second voltage is a maximum value of a variable range. In claim 1 or 2,
The first regulator is
Generating the first voltage based on a first reference voltage obtained by resistance division;
The second regulator is
A control circuit that generates the second voltage based on a second reference voltage obtained by resistive voltage division. A control circuit according to any one of claims 1 to 3;
The physical quantity detection element;
Physical quantity detection device including. The physical quantity detection device according to claim 4;
A signal processing circuit that acquires the physical quantity signal output from the physical quantity detection device and processes the physical quantity signal;
A communication circuit for transmitting the inertial data obtained by the processing of the signal processing circuit to the outside;
Inertial measurement device, including: A mobile positioning device which is mounted on a mobile and measures the position of the mobile,
An inertial measurement device according to claim 5;
A satellite signal receiving unit that receives satellite signals from positioning satellites and acquires positioning information superimposed on the satellite signals;
A position calculation unit that calculates the position of the mobile object based on the positioning information;
A posture calculation unit that calculates the posture of the moving object based on the inertial data output from the inertial measurement device;
A position correction unit that corrects the position based on the posture;
Mobile positioning device, including: The physical quantity detection device according to claim 4;
A case in which the physical quantity detection device is accommodated;
A processing unit housed in the case and processing output data from the physical quantity detection device;
A display unit housed in the case;
A translucent cover closing the opening of the case;
Including, portable electronic devices. The physical quantity detection device according to claim 4;
An arithmetic processing unit that performs arithmetic processing based on the physical quantity signal output from the physical quantity detection device;
Including electronic equipment. The physical quantity detection device according to claim 4;
An attitude control unit that controls an attitude based on the physical quantity signal output from the physical quantity detection device;
Including moving bodies.

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