JP2012098033A - Angular velocity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an angular velocity sensor that easily outputs an output signal not only in two's complement representation but also another signed numeric representation.SOLUTION: An angular velocity sensor of this invention for solving the above problem comprises: correction operation means 74 that corrects an output signal from an AD converter 73; and a signed numeric representation conversion circuit 76 in a subsequent stage of the correction operation means 74. Accordingly, the output signal can be converted from that of two's complement representation to off-set binary representation, so that the output signal can be easily output in another signed numeric representation.

Description

  The present invention particularly relates to an angular velocity sensor using a digital circuit used for attitude control of a moving body such as an aircraft or a vehicle, a navigation system, or the like.

  A conventional angular velocity sensor of this type has a configuration as shown in FIGS.

  Hereinafter, a conventional angular velocity sensor will be described with reference to the drawings.

  FIG. 11 is a block diagram showing a circuit of a conventional angular velocity sensor, and FIG. 12 is a block diagram showing a drive circuit and its failure detection circuit in the angular velocity sensor.

  In FIGS. 11 and 12, reference numeral 1 denotes a quartz crystal vibrator composed of an H-shaped tuning fork. The vibrator 1 has a pair of driving units 2 and a pair of driving units 2 disposed on opposite sides of the pair of driving units 2. The detection unit 3 includes an angular velocity detection electrode (not shown). A driving electrode 4 is provided on one side of the driving unit 2 of the vibrator 1, and a driving detection electrode 5 is provided on the other side of the driving unit 2. Reference numeral 6 denotes a drive circuit. The drive circuit 6 is electrically connected to the drive electrode 4 and the drive detection electrode 5 in the vibrator 1, and controls the vibrator 1 to have a constant amplitude. . Further, the drive circuit 6 is provided with two EEPROMs 6a, and the correction data is prevented from being falsified by comparing the two 8-bit correction data stored in the EEPROM 6a as shown in FIG. In the state, the drive signal is corrected. Reference numeral 7 denotes a failure diagnosis circuit. The failure diagnosis circuit 7 includes a window comparator 8 and a bit logic 9 that monitors an output signal of the window comparator 8. Reference numeral 10 denotes a detection circuit, which amplifies the electric charge output from the detection unit 3 in the vibrator 1 and converts it into a voltage, and outputs it as an output signal from the input / output terminal 11 to the outside.

  Next, the operation of the conventional angular velocity sensor configured as described above will be described.

  When an AC voltage is applied to the drive electrode 4 of the vibrator 1, the vibrator 1 resonates, and a charge corresponding to the vibration amplitude of the vibrator 1 is generated on the drive detection electrode 5 in the vibrator 1. The electric charge is amplified and adjusted by the drive circuit 6 and then input to the drive electrode 4 to control the vibrator 1 to vibrate with a constant amplitude. Further, when the amplitude deviates from a predetermined value due to variations in the vibrator 1, the amplitude is finely adjusted by rewriting the data of the EEPROM 6a in the drive circuit 6.

  When the angular velocity ω is applied to the vibrator 1, electric charges are generated in the angular velocity detection electrodes (not shown) provided in the pair of detection units 3. Then, the electric charge generated in the electrode for detecting the angular velocity (not shown) is converted into an output voltage by the detection circuit 10 and is sent to the other computer (not shown) as an angular velocity signal from the input / output terminal 11. Input and detect angular velocity.

  As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.

JP 2002-174521 A

  However, in the above-described conventional configuration, the two 8-bit correction data stored in the EEPROM 6a are based on the two's complement expression as shown in FIG. There has been a problem that an output signal cannot be output.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object of the present invention is to provide an angular velocity sensor that easily outputs an output signal not only with two's complement expression but also with other signed numerical expressions.

  In order to achieve the above object, the present invention has the following configuration.

  According to a first aspect of the present invention, there is provided a vibrator having a drive electrode, a first sense electrode, a second sense electrode, and a monitor electrode, and a drive circuit for driving the vibrator at a predetermined drive frequency. An analog-to-digital converter that converts an analog signal output from the sense electrode into a digital signal; and a correction calculation unit that corrects the output signal from the AD converter; According to this configuration, since the signed numerical expression conversion circuit is provided in the subsequent stage of the correction calculation means, the signed numerical expression conversion circuit outputs an offset binary expression from the two's complement expression. Since it can be converted into a signal, it has an operational effect that an output signal in another signed numerical expression can be easily output.

  According to the second aspect of the present invention, in particular, the AD converter includes a first DA conversion unit and a second DA conversion unit that output charge amounts of at least two levels, and the first sense electrode. Integrating the charges output from the first DA converter and the first integrating circuit for holding the integrated value, and integrating the charges output from the second sense electrode and the second DA converter. On the basis of the second integration circuit that holds the integration value, the comparison circuit that compares the output signals from the first integration circuit and the second integration circuit, and the output signal from the comparison circuit, The level of the output signal from the first DA conversion means and the second DA conversion means is switched. According to this configuration, a 1-bit digital signal is input from the AD converter to the signed numerical expression conversion circuit. This would be possible More, and has a effect that easily from the signed number representations conversion circuit can output a digital signal of two's complement representation or offset binary representation.

  The invention according to claim 3 of the present invention, in particular, is a substrate on which the vibrator electrode and the analog signal wiring pattern are provided on the upper surface, and is provided on the upper surface of the substrate and is electrically connected to the vibrator electrode on the substrate. A vibrator having a drive electrode, a first sense electrode, and a second sense electrode; and an IC provided in the recess in the substrate and driving the vibrator and processing an output signal from the vibrator, A switch bump joint is provided on the upper surface of the substrate, and the signal lines of the analog signal wiring pattern and the digital signal wiring pattern are made different so that the voltage applied to the switch bump joint changes, and the signed numeric expression conversion circuit is provided. The applied control signal is changed. According to this configuration, when the switch bump bonding portion is provided on the upper surface of the substrate, In addition, the voltage applied to the switch bump junction changes by changing the routing of the signal lines of the analog signal wiring pattern and the digital signal wiring pattern so that the control signal applied to the signed numerical expression conversion circuit changes. This has the effect of being able to output an output signal in a different numerical expression with a sign with one IC.

  As described above, the angular velocity sensor of the present invention includes a vibrator having a drive electrode, a first sense electrode, a second sense electrode, and a monitor electrode, a drive circuit that drives the vibrator at a predetermined drive frequency, An AD converter that converts an analog signal output from the sense electrode into a digital signal; and a correction calculation unit that corrects the output signal from the AD converter; According to this configuration, since the signed numerical expression conversion circuit is provided at the subsequent stage of the correction calculation means, the signed numerical expression conversion circuit outputs the output signal from the two's complement expression to the offset binary expression. Therefore, it is possible to easily provide an angular velocity sensor that outputs an output signal in another signed numerical expression. Than is.

1 is an exploded perspective view of an angular velocity sensor according to an embodiment of the present invention. The perspective view which shows the state which removed a part of upper cover from the same angular velocity sensor Side sectional view of the same angular velocity sensor Top view of a substrate that outputs a digital signal of 2's complement representation in the same angular velocity sensor Bottom view of substrate in same angular velocity sensor Top view of transducer in same angular velocity sensor Perspective view from below of IC in same angular velocity sensor Circuit diagram of angular velocity sensor according to one embodiment of the present invention Top view of a substrate that outputs a digital signal in an offset binary representation in the same angular velocity sensor (A)-(f) The figure which shows the operation state of the same angular velocity sensor Circuit block diagram of conventional angular velocity sensor A block diagram showing a drive circuit and its failure detection circuit in a conventional angular velocity sensor The figure which shows the state which preserve | saves the failure information in the conventional angular velocity sensor

  Hereinafter, an angular velocity sensor according to an embodiment of the present invention will be described with reference to the drawings.

  1 is an exploded perspective view of an angular velocity sensor according to an embodiment of the present invention, FIG. 2 is a perspective view showing a state in which a part of an upper cover is removed from the angular velocity sensor, and FIG. 3 is a side sectional view of the angular velocity sensor. 4 is a top view of the substrate in the angular velocity sensor, FIG. 5 is a bottom view of the substrate in the angular velocity sensor, FIG. 6 is a top view of the vibrator in the angular velocity sensor, and FIG. 7 is a perspective view from below of the IC in the angular velocity sensor. FIG. 8 is a circuit diagram of the angular velocity sensor in one embodiment of the present invention.

  1 to 8, reference numeral 11 denotes a substrate formed by laminating and firing ceramics. The substrate 11 is provided with a recess 12 on the upper surface, and on the inner bottom surface of the recess 12 as shown in FIG. A plurality of analog bump joints 13 for connecting transducers, an analog bump joint 14 for outputting analog signals to the outside, and a digital bump joint 15 are provided in a radial pattern. A vibrator electrode 16 is provided on the upper surface of the substrate 11. The substrate 11 is provided with an analog layer 17 from the same surface as the inner bottom surface of the recess 12 to the top surface, and the analog layer 17 includes the analog bump bonding portion 13 for connecting the vibrator and the analog layer 17. An electrically connected vibrator analog signal wiring pattern 18 is provided. Further, a digital layer 19 is provided on the substrate 11 from the same surface to the lower surface as the inner bottom surface of the recess 12, and the analog bump output portion 14 for analog signal output and the electrical layer are electrically connected to the digital layer 19. The output analog signal wiring pattern 20 connected to the digital bump and the digital signal wiring pattern 21 electrically connected to the digital bump bonding portion 15 are provided. Also, as shown in FIG. 4, on the inner bottom surface of the recess 12, an analog bump joint 13 for transducer connection and an analog bump joint 14 for analog signal output are provided on a side different from the side where the digital bump joint 15 is provided. Is provided. Also, as shown in FIG. 3, the transducer analog signal wiring pattern 18 provided on the analog layer 17 and the digital signal wiring pattern 21 provided on the digital layer 19 are configured so as not to cross each other. It is. Further, as shown in FIG. 4, the analog bump bonding portion 14 is provided with a GND potential analog bump bonding portion 14a. The digital bump bonding portion 15 is provided with a power supply digital bump bonding portion 15a and a switch bump bonding portion 15b. The GND potential analog bump bonding portion 14 a and the switch bump bonding portion 15 b are electrically connected by an analog signal wiring pattern 18. An X-axis vibrator 22 is provided with a piezoelectric thin film (not shown) made of PZT on the upper surface of a tuning-fork-shaped silicon substrate (not shown). The X-axis vibrator 22 is provided on the upper surface of the substrate 11. As shown in FIG. 6, a drive electrode 32, a first sense electrode 34, and a second sense electrode 35 are provided on the upper surface. Reference numeral 25 denotes a Y-axis vibrator. The Y-axis vibrator 25 is provided on the upper surface of the substrate 11, and, like the X-axis vibrator 22, the drive electrode 32, the first sense electrode 34, and the second electrode are formed on the upper surface. A sense electrode 35 is provided. The vibrator electrode 16 provided on the upper surface of the substrate 11 includes a drive electrode 32, a first sense electrode 34, a second sense electrode 35, and a wire line 26 in the X-axis vibrator 22 and the Y-axis vibrator 25. Are electrically connected.

  An IC 27 is provided in the concave portion 12 of the substrate 11, drives the X-axis vibrator 22 and the Y-axis vibrator 25 to vibrate, and outputs from the X-axis vibrator 22 and the Y-axis vibrator 25. A vibrator analog signal processing circuit unit 28 for processing signals is provided. The IC 27 is provided with a digital signal processing circuit unit 29. The digital signal processing circuit unit 29 converts an analog signal output from the vibrator analog signal processing circuit unit 28 into a digital signal. Yes. Further, a bump electrode 30 is provided on the lower surface of the IC 27 so as to be aligned in a square shape, and the bump electrode 30 is an analog bump bonding portion 13 for connecting a vibrator on the substrate 11 and for outputting an analog signal. The analog bump bonding portion 14 and the digital bump bonding portion 15 are electrically connected. That is, the X-axis vibrator 22 and the Y-axis vibrator 25 through the bump electrode 30 in the IC 27 through the analog bump joint 13 for vibrator connection, the vibrator analog signal wiring pattern 18, the vibrator electrode 16 and the wire line 26. A driving voltage is supplied to the driving electrode 32 in FIG. The IC 27 outputs output signals from the first sense electrode 34 and the second sense electrode 35 in the X-axis transducer 22 and the Y-axis transducer 25 to the wire line 26, the transducer electrode 16, and the transducer analog. In addition to being input via the signal wiring pattern 18, signal processing is performed by the transducer analog signal processing circuit unit 28 and the digital signal processing circuit unit 29, and the signal is output to the outside from the digital signal wiring pattern 21. The digital signal processing circuit unit 29 in the IC 27 is provided with a charge amplifier 36 as shown in FIG. 8, and the charge amplifier 36 has monitor electrodes in the X-axis vibrator 22 and the Y-axis vibrator 25. The electric charge output from 33 is inputted, and the inputted electric charge is converted into a voltage at a predetermined magnification. Reference numeral 37 denotes a band-pass filter. The output of the charge amplifier 36 is input to the band-pass filter 37, and a noise component of the input signal is removed to output a monitor signal. An AGC circuit 38 has a half-wave rectifying / smoothing circuit (not shown). The AGC circuit 38 generates a smoothed DC signal by half-wave rectifying the output signal of the bandpass filter 37. Based on this DC signal, the monitor signal output from the band-pass filter 37 is amplified or attenuated and output. Reference numeral 39 denotes a drive circuit. The output of the AGC circuit 38 is input to the drive circuit 39, and a drive signal is output to the drive electrodes 32 of the vibrators 22 and 25. The charge amplifier 36, the band pass filter 37, the AGC circuit 38, and the drive circuit 39 constitute a drive circuit 40.

  The PLL circuit 41 multiplies the monitor signal output from the bandpass filter 37 in the drive circuit 40, and integrates and reduces the phase noise in time to output it. The timing generation circuit 42 generates and outputs a timing signal based on a signal obtained by multiplying the monitor signal output from the PLL circuit 41. The PLL circuit 41 and the timing generation circuit 42 constitute a timing control circuit 43. Reference numeral 47 denotes first DA switching means. The first DA switching means 47 has a first reference voltage 49 and a second reference voltage 50, and the first reference voltage 49 and the second reference voltage 50. The voltage 50 is switched by a predetermined signal. Reference numeral 51 denotes DA output means. The DA output means 51 is connected to the capacitor 52 to which the output signal of the first DA switching means 47 is input and to both ends of the capacitor 52, and operates at the second timing Φ2. The switches 53 and 54 for discharging the electric charge of the capacitor 52 are included. The first DA switching means 47 and the first DA output means 51 constitute a first DA converting means 48, and the first DA converting means 48 has the capacitor 52 at a first timing Φ1. The electric charge corresponding to the reference voltage output from the first DA switching means 47 is input / output. Reference numeral 55 denotes a first switch, and the first switch 55 outputs an output signal composed of a current from the first sense electrode 34 at the first timing Φ1. Reference numeral 56 denotes a first integration circuit. The output of the first switch 55 is input to the first integration circuit 56 and is connected in parallel to the operational amplifier 57 and the feedback of the operational amplifier 57. And a capacitor 58.

  59 is a second DA switching means, and this second DA switching means 59 has a first reference voltage 60 and a second reference voltage 61, and the first reference voltage 60 and the second reference voltage 61. The voltage 61 is switched by a predetermined signal. Reference numeral 62 denotes second DA output means. The second DA output means 62 is connected to a capacitor 63 to which the output signal of the second DA switching means 59 is input, and to both ends of the capacitor 63. It is composed of switches 64a and 64b that operate at the timing Φ2 and discharge the capacitor 63. The second DA switching means 59 and the second DA output means 62 constitute a second DA converting means 66, and the second DA converting means 66 has the capacitor 63 at a second timing Φ2. The electric charge corresponding to the reference voltage output from the second DA switching means 59 is input / output. Reference numeral 65 denotes a second switch, and the second switch 65 outputs an output signal from the second sense electrode 35 at the first timing Φ1. Reference numeral 67 denotes a second integration circuit. The output of the second switch 65 is input to the second integration circuit 67 and is connected in parallel to the operational amplifier 68 and the feedback of the operational amplifier 68. The capacitor 69 is used. Reference numeral 70 denotes a comparison circuit. The comparison circuit 70 includes a comparator 71 that compares the integration signal output from the first integration circuit 56 with the integration signal output from the second integration circuit 67, and a D-type flip-flop 72. The D-type flip-flop 72 receives a 1-bit digital signal output from the comparator 71. The D-type flip-flop 72 latches the 1-bit digital signal at the start of the first timing Φ1 and outputs a latch signal. The latch signal is output from the first DA converter 48. The first DA switching means 47 inputs the first reference voltage 49 or the second reference voltage 50, and the second DA conversion means 66 inputs the second DA switching means 59 to the first DA voltage switching means 47. The reference voltage 60 or the second reference voltage 61 is switched. The first DA converter 48, the second DA converter 66, the first integration circuit 56, the second integration circuit 67, and the comparison circuit 70 constitute an AD converter 73 composed of a ΣΔ modulator. Yes. The AD converter 73 has the above-described configuration and ΣΔ modulates the charges output from the first sense electrode 34 and the second sense electrode 35 in the vibrators 22 and 25 and converts them into a 1-bit digital signal. Output.

  Reference numeral 74 denotes a correction calculation means. The correction calculation means 74 receives a 1-bit difference signal output from the flip-flop 72, and realizes a correction calculation between the 1-bit difference signal and predetermined correction information by replacement processing. is there. That is, as described above, the 1-bit difference signal input to the correction calculation unit 74 is “0”, “1”, “−1”, and for example, when the correction information is “5”, “0” “ The output is replaced with 5 ""-5 ". Reference numeral 75 denotes a digital filter. The digital filter 75 receives a digital signal output from the correction calculation means 74 and performs a filtering process to remove noise components. Reference numeral 76 denotes a signed numerical expression conversion circuit. The signed numerical expression conversion circuit 76 receives a two's complement digital signal from the digital filter 75. When a control signal having a LOW voltage level is input from the outside, the signed numerical expression conversion circuit 76 outputs a digital signal of 2's complement expression as it is.

  On the other hand, when a control signal having a high voltage level is input from the outside, a value corresponding to half of the full scale is added by the signed numerical expression conversion circuit 76, and an offset / binary digital signal is externally input. Is output. For example, when the output signal of 2's complement expression output from the digital filter 75 is a signal composed of 2 to the 16th power, the signal of 2 to the 15th power is added. The correction means 74, the digital filter 75, and the signed numerical expression conversion circuit 76 constitute a calculation means 77. Further, the calculation means 77 latches the 1-bit digital signal at the first timing Φ1, performs correction calculation and filtering processing, and outputs a multi-bit signal. The timing control circuit 43, the AD converter 73, and the calculation means 77 constitute a sense circuit. Reference numeral 78 denotes an upper lid, and the upper lid 78 protects the X-axis vibrator 22 and the Y-axis vibrator 25 by covering the upper surface of the substrate 11.

  Next, a manufacturing method of the angular velocity sensor according to the embodiment of the present invention configured as described above will be described.

  First, a method for manufacturing an angular velocity sensor that outputs a digital output signal expressed in two's complement will be described.

  An epoxy thermosetting resin is applied to the recess 12 provided on the upper surface of the substrate 11, and then the IC 27 is mounted on the recess 12, and the thermosetting resin is cured in a high temperature atmosphere, whereby the IC 27 is applied to the substrate 11. Then, the bump electrode 30 in the IC 27 is connected to the analog bump bonding portion 13 for connecting the vibrator on the substrate 11, the analog bump bonding portion 14 for outputting analog signals, the GND potential analog bump bonding portion 14 a, and the digital bump bonding portion 15. The power supply digital bump bonding portion 15a and the switch bump bonding portion 15b are electrically connected.

  Next, an epoxy-based thermosetting resin is applied to a position on the substrate 11 where the X-axis vibrator 22 and the Y-axis vibrator 25 are placed.

  Next, after placing the X-axis vibrator 22 and the Y-axis vibrator 25 on the upper surface of the substrate 11, the substrate 11 is put into a high-temperature bath (not shown) at about 150 ° C. for about 90 minutes. The X-axis vibrator 22 and the Y-axis vibrator 25 are fixed on the upper surface.

  Next, the X-axis vibrator 22 and the Y-axis vibrator 25 and the vibrator electrode 16 on the substrate 11 are electrically connected by wire bonding of the wire wire 26.

  Finally, an upper lid 78 is attached to the upper surface of the substrate 11.

  Similarly, a method for manufacturing an angular velocity sensor that outputs a digital output signal in an offset binary representation will be described.

  In this case, as shown in FIG. 9, after preparing the substrate 11 for connecting the analog signal wiring pattern 18 constituting the GND potential to the GND potential analog bump bonding portion 14 a, the bump electrode 30 in the IC 27 is vibrated on the substrate 11. The analog bump joint 13 for child connection, the analog bump joint 14 for analog signal output, the GND potential analog bump joint 14a, the digital bump joint 15, the power supply digital bump joint 15a and the switch bump joint 15b are electrically connected. To connect to.

  Next, the operation of the angular velocity sensor according to one embodiment of the present invention configured as described above will be described.

  When an AC voltage is applied to the drive electrode 32 of the X-axis vibrator 22 or the Y-axis vibrator 25, the vibrating body 31 resonates and charges are generated at the monitor electrode 33. The charge generated on the monitor electrode 33 is input to the charge amplifier 36 in the drive circuit 40 and converted into a sinusoidal output voltage. Then, the output voltage of the charge amplifier 36 is input to a band pass filter 37, and only the resonance frequency of the vibrating body 31 is extracted, and a sine waveform as shown in FIG. Further, the output signal of the bandpass filter 37 in the drive circuit 40 is input to a half-wave rectifying / smoothing circuit (not shown) included in the AGC circuit 38 to be converted into a DC signal. The AGC circuit 38 generates a signal for attenuating the output signal of the bandpass filter 37 in the drive circuit 40 when the DC signal is large, while the AGC circuit 38 in the drive circuit 40 when the DC signal is small. A signal that amplifies the output signal of the bandpass filter 37 is input to the drive circuit 39, and the vibration of the vibrating body 31 is adjusted to have a constant amplitude. Further, the sine wave signal shown in FIG. 10A is input to the timing control circuit 43, and the timing generation circuit 42 generates the sine wave signal shown in FIG. 10B by multiplying the sine wave signal by the PLL circuit 41. The first timing Φ1 and the second timing Φ2 shown in FIG. Then, this timing signal is input to the AD converter 73 and the correction calculation means 74 composed of the ΣΔ modulator as switch switching and latch timing of the latch circuit.

  Further, the vibrators 22 and 25 rotate at an angular velocity ω around the central axis in the longitudinal direction of the vibrating body 31 in a state where the vibrators 22 and 25 are flexibly vibrating in the driving direction illustrated in FIG. Then, a Coriolis force of F = 2 mV × ω is generated in the vibrators 22 and 25. Due to this Coriolis force, electric charges are generated in the first sense electrode 34 and the second sense electrode 35 of the vibrators 22 and 25 as shown in FIGS. 10C and 10D. Since the charges generated in the first sense electrode 34 and the second sense electrode 35 are generated by the Coriolis force, the phase is advanced 90 degrees from the signal generated in the monitor electrode 33. The output signals generated at the first sense electrode 34 and the second sense electrode 35 have a relationship between a positive polarity signal and a negative polarity signal, as shown in FIGS. 10 (c) and 10 (d).

  The operation of the AD converter 73 composed of the ΣΔ modulator in this case will be described below. The AD converter 73 operates by repeating the first timing Φ1 and the second timing Φ2, and the first sense electrode 34 in the vibrators 22 and 25 at the first timing Φ1 and the second timing Φ2. The positive or negative signal output from the second sense electrode 35 is ΣΔ modulated and converted into a 1-bit digital signal.

  The operations at the first timing Φ1 and the second timing Φ2 will be described one by one.

  Here, a predetermined angular velocity is applied to the vibrators 22 and 25 around the central axes of the vibrators 22 and 25, the vibrators 22 and 25 rotate, and the first sense electrode 34 and the second sense electrode 35. Let us consider a case where an output voltage corresponding to eight values is generated.

  First, at the first timing Φ1, an output signal composed of charges corresponding to eight values generated from the first sense electrode 34 in the vibrators 22 and 25 is held in the capacitor 58 in the first integration circuit 56, and The output signal held in the capacitor 58 is input to the inverting terminal 71 a of the comparator 71 in the comparison circuit 70. Similarly, an output signal generated from the second sense electrode 35 in the vibrators 22 and 25 is held in the capacitor 69 in the second integration circuit 67 and corresponds to the −8 value held in the capacitor 69. An output signal composed of electric charges is input to the non-inverting terminal 71 b of the comparator 71 in the comparison circuit 70. Then, a 1-bit digital signal “1” is input to the flip-flop 72 as a comparison result from the comparator 71, and is latched by the flip-flop 72 at the second timing Φ2. Then, at the second timing Φ2, the switch 53 and the switch 54 in the first DA output means 51 are turned on, the electric charge held in the capacitor 52 is discharged, and the switch in the second DA output means 62 64a and the switch 64b are turned on, and the electric charge held in the capacitor 63 is discharged. Then, the latch signal “1” from the flip-flop 72 is input to the first DA switching unit 47 in the first DA conversion unit 48 at the next first timing Φ1, and the charge corresponding to the −10 value is supplied. The generated second reference voltage 50 is switched. Similarly, it is input to the second DA switching means 59 in the second DA conversion means 66 and switched to the first reference voltage 60 that generates a charge corresponding to 10 values. Then, the charge corresponding to the charge corresponding to the −10 value of the second reference voltage 50 is stored in the capacitor 52 in the first DA output means 51 and is input to the first integration circuit 56 and the second A charge corresponding to a charge corresponding to 10 values of the first reference voltage 60 is stored in the capacitor 63 of the DA output means 62 and input to the second integration circuit 67. At the same time, the first switch 55 is turned ON, and the charge corresponding to the charge corresponding to the eight values generated from the first sense electrode 34 of the vibrators 22 and 25 is output to the first integration circuit 56. . Further, the second switch 65 is turned ON, and the charge corresponding to the charge corresponding to the eight values is input from the second sense electrode 35 to the second integration circuit 67.

  Thus, at the second timing Φ2, the sum of the charge amount indicated by the hatched portion in FIG. 10C and the charge amount output from the first DA conversion means 48 is stored in the capacitor 58 in the first integration circuit 56. An integrated output signal consisting of charges corresponding to six values is held in the first integrating circuit 56. Similarly, the capacitor 69 in the second integration circuit 67 is integrated with the sum of the charge amount indicated by the hatched portion in FIG. 10D and the charge amount output from the second DA conversion means 66 to obtain a −6 value. The second integration circuit 67 holds an output signal composed of charges corresponding to. Then, it is compared by the comparator 71 and output to the flip-flop 72 as a 1-bit digital signal. Then, by repeating such a cycle as described above, the voltage held in the first integration circuit 56 sequentially decreases by a charge corresponding to the binary value, while the voltage held in the second integration circuit 67 is Sequentially, the charge corresponding to the binary value is increased. As a result, an output signal of “1” is output until the voltage held in the first integration circuit 56 and the second integration circuit 67 becomes a charge corresponding to a zero value. After that, when the voltage held in the first integration circuit 56 becomes a charge corresponding to −2, and the voltage held in the second integration circuit 67 becomes a charge corresponding to a binary value, the comparator 71 Outputs a "-1" output signal. Then, an output signal of “−1” is input from the flip-flop 72 to the first DA switching unit 47 and the second DA switching unit 59, and from the first reference voltage 49 in the first DA conversion unit 48. A charge voltage corresponding to 10 values is output, the corresponding charge is held in the capacitor 52, and from the second reference voltage 61 in the second DA converter 66, the charge corresponding to -10 value is output. A voltage is output and the corresponding charge is held in the capacitor 63. Then, the first integration circuit 56 holds a charge voltage corresponding to 16 values, and the second integration circuit 67 holds a charge voltage corresponding to −16 values. Thereafter, the output voltages of the first integration circuit 56 and the second integration circuit 67 are sequentially changed by the charge corresponding to the binary value, and the output signal of “1” is output nine times, then “−1”. When the output signal is output once and converted into multi-bits, an output signal of “0.8” is output and detected as an angular velocity signal.

  At this time, as shown in FIG. 4, when the switch bump bonding portion 15b is electrically connected to the GND potential analog bump bonding portion 14a via the analog signal wiring pattern 18, the signed numerical expression conversion in the IC 27 is performed. A control signal having a LOW voltage level corresponding to the GND potential is input to the circuit 76. Then, a digital signal of 2's complement representation as shown in (Table 1) is output from the calculation means.

  On the other hand, as shown in FIG. 9, when the switch bump bonding portion 15 b is electrically connected to the power supply digital bump bonding portion 15 a via the digital signal wiring pattern 21, a signed numerical expression conversion circuit 76 in the IC 27. A high voltage level control signal corresponding to 3 V potential is input to the input signal. Then, an offset binary representation digital signal as shown in (Table 1) is output from the calculation means.

  The angular velocity sensor according to the present invention has an effect that an output signal can be easily output not only by a two's complement expression but also by other signed numerical expressions, and in particular, the attitude of a moving body such as an aircraft or a vehicle. It is useful as an angular velocity sensor using a digital circuit used in control, navigation systems, and the like.

DESCRIPTION OF SYMBOLS 11 Board | substrate 18 Analog signal wiring pattern 21 Digital signal wiring pattern 22, 25 Vibrator 32 Drive electrode 33 Monitor electrode 34 1st sense electrode 35 2nd sense electrode 40 Drive circuit 48 1st DA conversion means 56 1st integration Circuit 66 Second DA conversion means 67 Second integration circuit 70 Comparison circuit 73 AD converter 74 Correction calculation means 76 Signed numerical expression conversion circuit

Claims (3)

A vibrator having a drive electrode, a first sense electrode, a second sense electrode, and a monitor electrode, a drive circuit for driving the vibrator at a predetermined drive frequency, and an analog signal output from the sense electrode are digitally converted. An angular velocity sensor comprising an AD converter for converting into a signal and a correction calculation means for correcting an output signal from the AD converter, and further provided with a signed numerical value expression conversion circuit at a subsequent stage of the correction calculation means. The AD converter converts the charges output from the first DA conversion means and the second DA conversion means for outputting charge amounts of at least two levels, the first sense electrode, and the first DA conversion means. A first integrating circuit that integrates and holds the integrated value; a second integrating circuit that integrates the charges output from the second sense electrode and the second DA converting means and holds the integrated value; A comparison circuit for comparing output signals from the first integration circuit and the second integration circuit, and an output signal from the comparison circuit, based on the first DA conversion means and the second DA conversion means. The angular velocity sensor according to claim 1, wherein the angular velocity sensor is configured to switch a level of an output signal. A vibrator having a transducer electrode, an analog signal wiring pattern, and a digital signal wiring pattern provided on the upper surface, and a drive electrode and a detection electrode provided on the upper surface of the substrate and electrically connected to the transducer electrode on the substrate And an IC that is provided in the concave portion of the substrate and that vibrates and drives the vibrator and processes an output signal from the vibrator. A switch bump joint is provided on the upper surface of the substrate, and an analog signal wiring pattern and digital 2. The angular velocity sensor according to claim 1, wherein the voltage applied to the switch bump joint changes by changing the routing of the signal lines of the signal wiring pattern, and the control signal applied to the signed numerical expression conversion circuit changes.

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