JP2008209182A - Detection device, sensor and electronic device - Google Patents

Abstract

To provide a detection device and the like capable of realizing improvement of starting characteristics and monitoring of an oscillation state.
A detection device includes a drive circuit and a detection circuit. The drive circuit 40 includes a drive amplitude detection circuit 52 that detects the drive amplitude of the vibrator 10 (physical quantity transducer) and outputs a control voltage VC according to the detected drive amplitude. The detection circuit 60 has a gain of the detection signal. A gain control circuit 80 for adjusting The gain control circuit 80 adjusts the gain of the detection signal based on the control voltage VC from the drive amplitude detection circuit 52. The detection circuit 60 includes a determination circuit that compares the control voltage VC with a given determination voltage and outputs determination information notifying at least whether the vibrator 10 is in a steady oscillation state or an oscillation starting process.
[Selection] Figure 1

Description

  The present invention relates to a detection device, a sensor, and an electronic device.

  Electronic devices such as a digital camera, a video camera, a mobile phone, and a car navigation system incorporate a gyro sensor for detecting a physical quantity that changes due to an external factor. Such a gyro sensor detects a physical quantity such as an angular velocity and is used for so-called camera shake correction, attitude control, GPS autonomous navigation, and the like.

  In recent years, a piezoelectric vibration gyro sensor has attracted attention as one of the gyro sensors. Among them, a quartz piezoelectric vibration gyro sensor using quartz as a piezoelectric material is expected as an optimum sensor for incorporation into many devices. In this vibration gyro sensor detection device, a desired signal, which is a signal corresponding to the Coriolis force generated by the rotation of the gyro sensor, is detected to obtain the rotational angular velocity.

  In such a vibration gyro sensor, the vibrator is driven by a drive circuit to oscillate the vibrator. The detection circuit receives a detection signal from the vibrator in the steady oscillation state and detects a desired signal.

However, a certain amount of time is required until the vibrator is in a steady oscillation state, and a desired specification sensitivity cannot be obtained unless the vibrator is in a steady oscillation state. In particular, in a vibrator having a high Q value such as a crystal, the oscillation is highly stable, but it takes time to reach a steady oscillation state, and there is a problem that the starting characteristic is inferior. Further, the conventional vibration gyro sensor has a problem that it cannot be determined from the outside whether the vibrator is in a steady oscillation state or an oscillation starting process.
JP-A-3-226620

  The present invention has been made in view of the technical problems as described above, and an object of the present invention is to provide a detection device, a sensor, and an electronic device that can realize improvement of starting characteristics and monitoring of an oscillation state. It is in.

  The present invention includes a drive circuit that outputs a drive signal to drive a physical quantity transducer, and a detection circuit that receives a detection signal from the physical quantity transducer and detects a desired signal from the detection signal, and the drive circuit includes the physical quantity transducer And a drive amplitude detection circuit that outputs a control voltage corresponding to the detected drive amplitude. The detection circuit includes a gain control circuit that adjusts a gain of a detection signal. The present invention relates to a detection device that adjusts the gain of a detection signal based on the control voltage from the drive amplitude detection circuit.

  According to the present invention, the drive amplitude of the physical quantity transducer is detected, and a control voltage corresponding to the detected drive amplitude is supplied to the gain control circuit on the detection side. The gain control circuit adjusts the gain based on this control voltage. In this way, since the detection-side gain is adjusted according to the drive amplitude, the detection apparatus can be activated at a high speed, and the activation characteristics can be improved.

  In the present invention, the gain control circuit may adjust the gain of the detection signal so as to be inversely proportional to the drive amplitude in the drive circuit.

  In the present invention, the gain control circuit may perform sensitivity correction to bring the sensitivity of the detection circuit close to the specification sensitivity before the drive amplitude in the drive circuit reaches the specification amplitude.

  This makes it possible to perform various processes using the output of the detection device even during a period before the drive amplitude reaches the specification amplitude.

  In the present invention, the physical quantity transducer is a vibrator, and the gain control circuit may perform sensitivity correction to bring the sensitivity of the detection circuit close to the specification sensitivity before the vibrator enters a steady oscillation state. Good.

  In this way, it is possible to perform various processes using the output of the detection device even during the period before the vibrator enters the steady oscillation state.

  In the present invention, the detection circuit may include an offset adjustment circuit that adjusts an offset of the detection signal, and the gain control circuit may be provided on the upstream side of the offset adjustment circuit.

  By doing so, it is possible to prevent a situation in which the offset adjusted by the offset adjustment is shifted due to the gain control of the gain control circuit.

  In the present invention, the physical quantity transducer is a vibrator, and the control voltage from the drive amplitude detection circuit is compared with a given determination voltage to determine whether the vibrator is in a steady oscillation state or an oscillation start process. A determination circuit that outputs determination information to be notified may be included.

  If such determination information is output, it is possible to easily know whether the vibrator is in a steady oscillation state or an oscillation starting process using the determination information, and the convenience of the application using the output of the detection device Can be improved.

  In the present invention, the determination circuit compares the control voltage with a first determination voltage, and determines that the vibrator is in a steady oscillation state, the first determination monitor signal is output as the first output. Output to the terminal, compare the control voltage with a second determination voltage, and if it is determined that the vibrator is in the oscillation starting process, output a second determination monitor signal to the second output terminal. Also good.

  In this way, it is possible to determine whether the vibrator is in a steady oscillation state or an oscillation starting process only by monitoring the first and second determination monitor signals, so that convenience can be further improved.

  In the present invention, the gain control circuit performs sensitivity correction of the detection signal, and the determination circuit performs sensitivity correction by the gain control circuit although the drive amplitude in the drive circuit does not reach the specification amplitude. It is also possible to output determination information that informs the user.

  If it does in this way, it will be judged that the output of a detection apparatus is effective for the time being, and it will become possible to perform various processes using the output of a detection apparatus.

  In the present invention, the determination circuit compares the control voltage with a first determination voltage, and determines that the vibrator is in a steady oscillation state, the first determination monitor signal is output as the first output. Output to a terminal, compare the control voltage with a second determination voltage, and if it is determined that the vibrator is in an oscillation starting process, output a second determination monitor signal to the second output terminal; When it is determined that the drive amplitude in the drive circuit does not reach the specified amplitude but sensitivity correction is performed by the gain control circuit, a third determination monitor signal is output to the third output terminal. Also good.

  In this way, it is possible to determine that the output of the detection device is valid for the time being only by monitoring the third determination monitor signal.

  In the present invention, the drive circuit may include a gain control circuit that controls a gain of a drive signal in the drive circuit based on the control voltage from the drive amplitude detection circuit.

  In this way, automatic adjustment of the drive-side gain is possible.

  In the present invention, the detection circuit includes an amplification circuit that amplifies a detection signal from the physical quantity transducer, and a synchronous detection circuit that performs synchronous detection based on a synchronization signal from the drive circuit, and the gain control circuit includes: It may be provided between the amplifier circuit and the synchronous detection circuit.

  If the gain control circuit is provided on the upstream side of the synchronous detection circuit in this way, the adverse effect of flicker noise can be minimized and the S / N ratio can be improved.

  The present invention also includes a drive circuit that outputs a drive signal to drive a physical quantity transducer, and a detection circuit that receives a detection signal from the physical quantity transducer and detects a desired signal from the detection signal, and the drive circuit includes the physical quantity A drive amplitude detection circuit that detects a drive amplitude of the transducer and outputs a control voltage corresponding to the detected drive amplitude, wherein the physical quantity transducer is a vibrator, and is supplied with the control voltage from the drive amplitude detection circuit; And a detection device including a determination circuit that outputs determination information that at least informs whether the vibrator is in a steady oscillation state or an oscillation start process.

  According to the present invention, it is possible to determine whether the vibrator is in a steady oscillation state or an oscillation start process and output the determination information only by comparing the control voltage from the drive amplitude detection circuit with a given determination voltage. become. If such determination information is output, it is possible to easily know whether the vibrator is in a steady oscillation state or an oscillation starting process using the determination information, and the convenience of the application using the output of the detection device Can be improved.

  In the present invention, the determination circuit compares the control voltage with a first determination voltage, and determines that the vibrator is in a steady oscillation state, the first determination monitor signal is output as the first output. Output to the terminal, compare the control voltage with a second determination voltage, and if it is determined that the vibrator is in the oscillation starting process, output a second determination monitor signal to the second output terminal. Also good.

  The present invention also relates to a sensor including any one of the detection devices described above and the physical quantity transducer.

  The present invention also relates to an electronic device including the sensor described above and a processing unit that performs processing based on detection information of the sensor.

  Hereinafter, preferred embodiments of the present invention will be described in detail. The present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in the present embodiment are indispensable as means for solving the present invention. Not necessarily. For example, a case where the physical quantity transducer is a piezoelectric vibrator (vibration gyro) and the sensor is a gyro sensor will be described below as an example, but the present invention is not limited to this.

1. Configuration of Detection Device FIG. 1 shows a configuration example of the detection device 30 of the present embodiment. The detection device 30 includes a drive circuit 40 and a detection circuit 60. The detection device 30 is not limited to the configuration of FIG. 1, and various modifications such as omitting some of the components or adding other components are possible.

  The vibrator 10 (vibration gyro), which is a physical quantity transducer, is a piezoelectric vibrator formed of a piezoelectric material such as quartz. FIG. 2A shows a tuning fork type piezoelectric vibrator as an example of the vibrator 10. The vibrator 10 includes drive vibrators 11 and 12 and detection vibrators 16 and 17. The drive vibrators 11 and 12 are provided with drive terminals 2 and 4, and the detection vibrators 16 and 17 are provided with detection terminals 6 and 8. FIG. 2A shows an example in which the vibrator 10 is a tuning fork type, but the vibrator 10 of the present embodiment is not limited to such a structure. For example, it may be T-shaped or double T-shaped. Further, the piezoelectric material of the vibrator 10 may be other than quartz, for example, piezoelectric ceramic. Further, the vibrator 10 that is a physical quantity transducer may be an electrostatic MEMS (Micro Electro Mechanical Systems) that similarly performs a drive / detection operation by electrostatic capacitance. A physical quantity transducer is an element for converting a physical quantity (a quantity representing the degree of the property of an object, the unit of which is defined) into another physical quantity. As physical quantities to be converted, in addition to Coriolis force, force such as gravity, acceleration, and mass can be considered. In addition to the current (charge), the physical quantity obtained by the conversion may be a voltage or the like.

  The drive circuit 40 outputs a drive signal VD (drive voltage, drive current) to drive the vibrator 10 (physical quantity transducer in a broad sense) and receives a feedback signal IFD (output current) from the vibrator 10. As a result, an oscillation loop is formed to excite the vibrator 10. The detection circuit 60 receives the detection signals (detection current, charge) ISP and ISM from the vibrator 10 driven by the drive signal VD, and detects (extracts) a desired signal (Coriolis force signal) from the detection signals ISP and ISM.

  Specifically, an alternating drive signal VD from the drive circuit 40 is applied to the drive terminal 2 of the drive vibrator 11 shown in FIG. Then, the driving vibrator 11 starts to vibrate due to the reverse voltage effect, and the driving vibrator 12 also starts to vibrate due to the tuning fork vibration. At this time, a current (charge) generated by the piezoelectric effect of the drive vibrator 12 is fed back from the drive terminal 4 to the drive circuit 40 as a feedback signal IFD. As a result, an oscillation loop including the vibrator 10 is formed.

  When the drive vibrators 11 and 12 vibrate, the detection vibrators 16 and 17 vibrate in the direction shown in FIG. Then, currents (charges) generated by the piezoelectric effect of the detection vibrators 16 and 17 are output from the detection terminals 6 and 8 as detection signals ISP and ISM. Then, the detection circuit 60 receives the detection signals ISP and ISM from the vibrator 10 and detects a desired signal (desired wave) that is a signal corresponding to the Coriolis force.

  That is, when the vibrator 10 (gyro sensor) rotates around the detection axis 19 in FIG. 2A, a Coriolis force Fc is generated in a direction orthogonal to the vibration direction of the vibration speed v. For example, FIG. 2B schematically shows a view of the detection shaft 19 of FIG. In FIG. 2B, when the angular velocity when rotating around the detection axis 19 is Ω, the mass (equivalent mass) of the vibrator is m, and the vibration speed of the vibrator is v, the Coriolis force is Fc = 2. It is expressed as × m × v × Ω. Therefore, when the detection circuit 60 detects (extracts) a desired signal that is a signal corresponding to the Coriolis force, the rotational angular velocity Ω of the gyro sensor (vibrator) can be obtained.

  The vibrator 10 has a drive side resonance frequency fd and a detection side resonance frequency fs. Specifically, the natural resonance frequency of drive vibrators 11 and 12 (the natural resonance frequency of drive vibration mode) is fd, and the natural resonance frequency of detection vibrators 16 and 17 (the natural resonance frequency of detection vibration mode). Is fs. In this case, the drive vibrators 11 and 12 and the detection vibrators 16 and 17 can perform the detection operation and have an appropriate inter-mode coupling that does not cause unnecessary resonance coupling. Has a certain frequency difference. The detuning frequency Δf = | fd−fs |, which is this frequency difference, is set to a frequency that is sufficiently smaller than fd and fs.

  The drive circuit (oscillation control circuit) 40 includes an amplification circuit 42, a phase adjustment circuit 44, a binarization circuit 46, and an AGC circuit (automatic gain control circuit) 50. Note that some of these components (for example, the phase adjustment circuit) may be omitted, or other components may be added.

  The driving side amplification circuit (I / V conversion circuit) 42 amplifies the feedback signal IFD from the vibrator 10. Specifically, the output current (charge) as the feedback signal IFD is amplified and converted to a voltage, and the amplified signal VD1 is output.

  A phase adjustment circuit (phase shifter, phase shift circuit) 44 adjusts the phase of the drive signal and outputs a signal VD2 after the phase adjustment. The phase adjustment circuit 44 can be realized by a high-pass filter, for example. The place where the phase adjustment circuit 44 is provided in the oscillation loop is arbitrary.

  The binarization circuit 46 performs binarization processing on the amplified signal VD2 that is a sine wave, and a synchronization signal (reference signal) CLK obtained by the binarization processing is supplied to the synchronization detection circuit 100 of the detection circuit 60. Output. The binarization circuit 46 can be realized by a comparator or the like that receives a sine wave (alternating current) signal VD2 and outputs a rectangular wave synchronization signal CLK.

  An AGC (Automatic Gain Control) circuit 50 automatically adjusts the gain of the drive signal. Specifically, the amplified signal VD2 is monitored to control the gain of the oscillation loop. The AGC circuit 50 includes a drive amplitude detection circuit 52 and a gain control circuit 54. Here, the drive amplitude detection circuit 52 detects the drive amplitude of the vibrator 10 (the physical quantity transducer) and outputs a control voltage VC corresponding to the detected drive amplitude. The gain control circuit 54 controls the gain of the drive signal in the drive circuit 40 based on the control voltage VC from the drive amplitude detection circuit 52. The gain control circuit 54 can be realized by a gain control amplifier.

  That is, in the drive circuit 40, in order to keep the sensitivity of the gyro sensor constant, it is necessary to keep the amplitude of the drive voltage supplied to the vibrator 10 (drive vibrator) constant. For this reason, an AGC circuit 50 for automatically adjusting the gain is provided in the oscillation loop of the drive vibration system. Specifically, the AGC circuit 50 automatically adjusts the gain variably so that the drive amplitude (vibration speed v of the vibrator) is constant. At the time of oscillation startup, the gain of the oscillation loop is set to a gain larger than 1 in order to enable high-speed oscillation startup. Further, the signal VD for driving the vibrator 10 may be a sine wave or a rectangular wave.

  The detection circuit 60 includes an amplification circuit 70, a gain control circuit 80, a synchronous detection circuit 100, and a filter unit 110. Note that some of these components (for example, the filter unit) may be omitted, or other components (for example, an offset adjustment circuit) may be added.

  The detection-side amplifier circuit 70 amplifies the detection signals ISP and ISM from the vibrator 10. Specifically, the current (charge) generated in the vibrator 10 is converted into a voltage and amplified.

  A gain control circuit (sensitivity adjustment circuit) 80 adjusts the gain (sensitivity) of the detection signal. Specifically, the gain of the detection signal is adjusted based on the control voltage VC from the drive amplitude detection circuit 52 (AGC circuit 50). The gain control circuit 80 adjusts the gain of the detection signal so as to be inversely proportional (inversely proportional) to the drive amplitude in the drive circuit 40. Further, in a period before the drive amplitude in the drive circuit 40 reaches the specification amplitude, sensitivity correction (sensitivity correction) is performed so that the sensitivity of the detection circuit 60 approaches the specification sensitivity. For example, in a period before the vibrator 10 enters the steady oscillation state, sensitivity correction is performed so that the sensitivity approaches the specification sensitivity.

  A synchronous detection circuit (detection circuit, demodulation circuit) 100 performs synchronous detection based on a synchronous signal (synchronous clock, reference signal) CLK. This synchronous detection makes it possible to eliminate unnecessary signals for mechanical vibration leakage.

  The filter unit 110 provided on the subsequent stage side of the synchronous detection circuit 100 performs a filtering process on the signal VS6 after the synchronous detection. Specifically, low-pass filter processing for removing high frequency components is performed.

  The detection signal (sensor signal) from the vibrator 10 includes a desired signal (desired wave) and an unnecessary signal (unnecessary wave). Since the amplitude of the unnecessary signal is generally about 100 to 500 times the amplitude of the desired signal, the required performance for the detection device 30 is increased. This unnecessary signal may be caused by mechanical vibration leakage, electrostatic coupling leakage, detuning frequency Δf, 2fd (2ωd), DC offset, or the like. The unnecessary signal of mechanical vibration leakage is generated due to an imbalance of the shape of the vibrator 10 or the like. 1 is generated when the drive signal VD in FIG. 1 leaks to the input terminals of the ISP and ISM through the parasitic capacitors CP and CM.

  FIGS. 3A to 3C are frequency spectra for explaining the removal of unnecessary signals. FIG. 3A shows a frequency spectrum before synchronous detection. As shown in FIG. 3A, in the detection signal before synchronous detection, there is a DC offset unnecessary signal in the DC frequency band. Further, an unnecessary signal and a desired signal of mechanical vibration leakage exist in the frequency band of fd.

  FIG. 3B shows a frequency spectrum after synchronous detection. The desired signal in the fd frequency band in FIG. 3A appears in the DC and 2fd frequency bands after synchronous detection, as shown in FIG. 3B. Further, an unnecessary signal (DC offset) in the DC frequency band of FIG. 3A appears in the fd frequency band after synchronous detection, as shown in FIG. 3B. Further, an unnecessary signal (mechanical vibration leakage) in the fd frequency band in FIG. 3A appears in the 2fd frequency band after synchronous detection, as shown in FIG. 3B.

  FIG. 3C shows the frequency spectrum after the filter processing. By smoothing (LPF) the signal after synchronous detection by the filter unit 110, it is possible to remove frequency components of unnecessary signals in frequency bands such as fd and 2fd.

2. Detailed Configuration Example FIG. 4 shows a detailed configuration example of the detection apparatus 30 of the present embodiment. As shown in FIG. 4, the driving-side amplifier circuit 42 includes an I / V (current / voltage) conversion circuit 43. FIG. 5A shows a configuration example of the I / V conversion circuit 43. The I / V conversion circuit 43 includes a capacitor CA1 and a resistor RA1 provided between nodes NA1 and NA2, and an operational amplifier (operational amplifier) OPA. An input node NA1 is connected to the first input terminal (inverted input terminal) of the operational amplifier OPA, and an AGND power supply node (reference power supply voltage node) is connected to the second input terminal (non-inverted input terminal).

  The drive amplitude detection circuit 52 includes a full-wave rectifier circuit 56 and a differential amplifier OPG. The full-wave rectifier circuit (integrator) 56 converts an AC signal VD2 that is a signal amplified by the amplifier circuit 42 into a DC signal. The differential amplifier OPG outputs a control voltage VC corresponding to the difference between the voltage VAR (voltage corresponding to the drive amplitude) of the DC signal from the full-wave rectifier circuit 56 and the reference voltage Vr1. That is, the control voltage VC that increases as the difference between the voltages VAR and Vr1 increases is output.

  The drive-side gain control circuit 54 includes a gain control amplifier GCAA. FIG. 6 shows a configuration example of the gain control amplifier GCAA. The GCAA includes a differential unit (differential stage) 200 and an output unit (output stage) 202. The differential unit 200 includes a bias current transistor TC1, transistors TC2 and TC3 forming a differential pair, and transistors TC4 and TC5 forming a current mirror circuit. The output unit 202 includes P-type and N-type transistors TC6 and TC7 whose gates are connected to the output of the differential unit 200. In FIG. 6, the output unit 202 operates using the control voltage VC from the drive amplitude detection circuit 52 as the power supply voltage (high potential side). That is, the control voltage VC is supplied to the source of the transistor TC6. With such a configuration, gain control that is inversely proportional to the control voltage VC can be realized.

  The gain control amplifier GCAA is not limited to the configuration shown in FIG. 6, and various modifications such as changing the connection configuration of the transistors of the differential unit 200 and the output unit 202 are possible. For example, the gain may be controlled by variably adjusting the resistance of an amplifier circuit composed of a resistor and an operational amplifier based on the control voltage VC.

  The detection-side amplifier circuit 70 includes the I / V (Q / V) conversion circuits 72 and 74 described with reference to FIG. 5A and the differential amplifier circuit 76 whose configuration example is shown in FIG. The 1 and 4, a differential amplifier circuit is used as the amplifier circuit 70, but a single-ended amplifier circuit as shown in FIG. 5C may be used. In this case, the amplifier circuit 70 can be constituted by one I / V conversion circuit 78.

  The detection-side gain control circuit 80 includes a gain control amplifier GCAB. As this GCAB, the gain control amplifier having the configuration described in FIG. 6 can be used. That is, a gain control amplifier having the same configuration as that of the drive-side GCAA can be used. Note that, for example, a modification in which the gain is controlled by adjusting the resistance value of the differential amplifier circuit 76 in FIG.

  The synchronous detection circuit 100 performs synchronous detection based on the synchronous signal (reference signal) CLK from the drive circuit 40. This synchronous detection circuit 100 includes a switching element SE1 that is controlled to be turned on / off by a synchronization signal CLK, a switching element SE2 that is controlled to be turned on / off by an inverted synchronization signal CLKN, and an inverting amplification operational amplifier OPE. Synchronous detection is performed using this method.

  The synchronous detection circuit 100 may be a double balance mixer type. The extraction of the desired signal and the removal of the unnecessary signal described with reference to FIG. 3A and the like may be realized by a detection method different from that of the normal synchronous detection circuit 100. For example, instead of the synchronous detection circuit 100, a detection circuit configured by an A / D conversion circuit that performs A / D conversion of a detection signal may be provided to extract a desired signal and remove an unnecessary signal.

  The filter unit 110 includes a pre-filter (pre-filter) 112, an SCF (switched capacitor filter), and a post filter 114 (post-filter). The SCF (discrete time type filter in a broad sense) removes the component of the detuning frequency Δf = | fd−fs | corresponding to the difference between the drive side resonance frequency fd and the detection side resonance frequency fs of the vibrator, and the desired signal Frequency component (DC component) is allowed to pass through. The prefilter 112 and the postfilter 114 are continuous time filters, and the postfilter 114 also serves as an output amplifier.

3. As described above, the Coriolis force Fc can be expressed by the following equation.

Fc = 2 × m × v × Ω (1)
In the case of a vibrating gyroscope, the speed v can be expressed by the following equation.

v = a × sin (ω0 × t) (2)
Here, a is the drive amplitude, and ω0 is the angular velocity of the drive vibration. From the above equations (1) and (2), the Coriolis force Fc can be expressed as the following equation.

Fc = 2 × m × Ω × a × sin (ω0 × t) (3)
That is, the Coriolis force Fc is proportional to the gyro angular velocity Ω and the drive amplitude a. If the drive amplitude a is constant, the Coriolis force is proportional to the angular velocity Ω. Therefore, the angular velocity Ω of the gyro can be detected by detecting the magnitude of the Coriolis force Fc. That is, the angular velocity Ω can be detected by detecting a physical quantity that changes due to the Coriolis force Fc.

  Further, as apparent from the above equation (3), the gyro signal (detection signal) is output as an AM modulated wave having the drive vibration frequency fd as the carrier frequency.

  Therefore, in FIG. 1 and FIG. 4, a drive circuit 40 that drives the vibrator 10 while performing gain adjustment to make the drive amplitude a constant, and a detection circuit 60 that performs detection and demodulation using the drive cycle as a synchronous detection signal are provided. Yes.

  Specifically, as shown in FIG. 7A, the drive amplitude detection circuit 52 outputs a control voltage VC corresponding to the drive amplitude. For example, the control voltage VC that is directly proportional to the drive amplitude is output. On the other hand, as shown in FIG. 7B, the gain control circuit 54 controls the gain so as to be inversely proportional to the drive amplitude, and the gain KA can be expressed by the following equation.

KA = b0 + b1 / VC (4)
For example, if the control voltage in the steady oscillation state is VC = VC0, the gain KA0 in the steady oscillation state can be expressed by the following equation.

KA0 = b0 + b1 / VC0 (5)
Further, the maximum gain KAmax of the gain control circuit 54 shown in FIG. 7B is determined by the minimum control voltage VCmin shown in FIG. 7A, and the output range of the differential amplifier OPG of FIG. 4, AGND and the reference voltage Vr1. Limited by setting.

  The present embodiment is characterized in that the detection-side gain is controlled according to the drive amplitude. Therefore, in FIGS. 1 and 4, a gain control circuit 80 that performs gain control based on the control voltage VC is provided in the detection circuit 60.

  For example, FIG. 8A shows the amplitude starting characteristic of the oscillation circuit. In FIG. 8A, at the time T0, after reaching the bias point (amplitude center), the oscillation amplitude gradually grows. At time T1, a steady oscillation state in which the amplitude is constant is obtained.

  As described in the above equation (3), the Coriolis force is proportional to the drive amplitude a. Therefore, as shown in FIG. 8B, the sensitivity reaches the specified sensitivity in the steady oscillation state after time T1. That is, when the drive amplitude becomes the specified amplitude in FIG. 7A and the vibrator 10 enters the steady oscillation state, the specified sensitivity can be obtained.

  The sensitivity (V / degree / sec) is, for example, the amount of change per unit angular velocity of the output voltage VSQ as shown in FIG. 9, and corresponds to the slope of the straight line of the DC output voltage VSQ. Normally, initial sensitivity adjustment is performed after power is turned on, and then initial offset adjustment is performed. Further, the specification sensitivity shown in FIG. 8B is a sensitivity that becomes a target (typical value) determined by the specification of the detection device 30 (gyro sensor), and is a characteristic parameter that represents the performance of the sensor. The specification amplitude shown in FIG. 7A is a drive amplitude when the sensitivity reaches the specification amplitude, and is a drive amplitude in a steady oscillation state.

  For example, a vibrator having a low Q value, such as a piezoelectric ceramic or silicon MEMS, has low oscillation stability but has an advantage of a short start-up time (for example, 100 ms or less). On the other hand, a resonator having a high Q value, such as quartz, has high oscillation stability and high gyro signal characteristics, but has the disadvantage of a long start-up time. Therefore, in a resonator having a high Q value such as a crystal, as shown in FIG. For this reason, as indicated by E1 in FIG. 10B, it takes time (for example, 200 to 1000 ms) until the sensitivity on the detection side reaches the specification sensitivity that is a desired sensitivity characteristic. That is, the crystal resonator is highly stable but inferior in starting characteristics. If the starting characteristics are inferior, the following problems occur in an electronic device incorporating a gyro sensor such as a crystal resonator.

  For example, in a digital still camera having a camera shake correction lens and a gyro sensor incorporated in the lens, power may be supplied to the lens from the moment the shutter is pressed. In this case, if the startup time of the gyro sensor is long, camera shake correction may not be in time. In the car navigation system, before satellite acquisition by GPS, position information is acquired using a gyro sensor, a vehicle speed sensor, or the like. Therefore, if the startup time of the gyro sensor is long, it takes time to acquire the position information.

  Further, when a gyro sensor is incorporated in a portable electronic device, power is supplied to the gyro sensor by a battery. Therefore, it is necessary to reduce the power consumption of the gyro sensor as much as possible and to extend the battery life. For this reason, it is desirable to adopt a power saving method in which the power supply to the gyro sensor is stopped during the period when the angular velocity is not detected, and the power is supplied from the battery only during the period during which the gyro sensor is used. However, when the startup time of the gyro sensor is long, it is difficult to realize such a power saving method.

  In order to solve such a problem, the present embodiment employs a technique of variably controlling the detection-side gain in inverse proportion to the drive amplitude. That is, the gain control circuit 80 on the detection side in FIGS. 1 and 4 receives the control voltage VC proportional to the drive amplitude from the drive circuit 40, and performs gain adjustment based on the control voltage VC. That is, even before the drive amplitude reaches the specified amplitude, the sensitivity correction is performed by variably controlling the gain on the detection side based on the control voltage VC so that the sensitivity of the gyro signal becomes equal to the specified sensitivity.

  For example, the gain control circuit 80 (gain control amplifier GCAB) controls the gain so as to be inversely proportional to the drive amplitude, and the gain KB can be expressed by the following equation.

KB = c0 + c1 / VC (6)
If the control voltage in the steady oscillation state is VC = VC0, the gain KB0 in the steady oscillation state can be expressed by the following equation.

KB0 = c0 + c1 / VC0 (7)
As shown in FIG. 7A, the control voltage VC is saturated to VCmin in the lower limit range due to the output range of the gain control circuit 80 (GCAB) and the setting of AGND and the reference voltage Vr1. Then, as indicated by F1 in FIG. 11A, the gain of the gain control circuit 80 is KB = KBmax during the period from T0 to T3 in which the control voltage is VC = VCmin. At time T3, when the oscillation amplitude grows and the control voltage VC increases from VCmin, the gain KB changes in inverse proportion to the control voltage VC corresponding to the drive amplitude, as indicated by F2 in FIG. .

  On the other hand, as shown by F3 in FIG. 11B, the sensitivity increases during the period from T0 to T3 and approaches the specification sensitivity. That is, in the present embodiment, the gain is controlled by the gain control circuit 80 so that the sensitivity is close to the specification sensitivity. As indicated by F4, the sensitivity becomes equal to the specified sensitivity at time T3. As described above, when the sensitivity becomes equal to the specification sensitivity, the system side can appropriately use the output of the detection device 30.

  For example, when the Q value of the vibrator is high as shown in FIG. 10A and the growth of the oscillation amplitude is slow, the sensitivity is long until the sensitivity becomes equal to the specified sensitivity as indicated by F5 in FIG. It takes time. Accordingly, it takes time until the output of the detection device 30 has an appropriate sensitivity, and the startup time is delayed.

  On the other hand, in this embodiment, as shown by F3 and F4 in FIG. 11B, detection is performed in a period before the drive amplitude reaches the specified amplitude (period before the oscillation of the vibrator enters the steady oscillation state). Sensitivity correction is performed so that the sensitivity of the circuit 60 approaches the specification sensitivity. Therefore, the output voltage VSQ with appropriate sensitivity can be obtained even in a period before the vibrator enters the steady oscillation state, and the startup time can be shortened.

  For example, as a technique for shortening the start-up time, a technique for contriving the circuit configuration of the drive circuit 40 and shortening the time until a steady oscillation state can be considered. However, this technique has a limit. If the sensitivity of the output voltage VSQ of the detection circuit 60 does not approach the specification sensitivity quickly even if the time until the steady oscillation state is shortened, it is not so much for the system side that performs processing using this output voltage VSQ. has no meaning.

  In this regard, in the present embodiment, correction is performed so that the sensitivity is close to the specification sensitivity in a period before the vibrator is in a steady oscillation state (period before T2). Therefore, the system side can perform various processes using the output voltage VSQ of the detection device 30 before entering the steady oscillation state, and convenience can be improved. That is, the system side may want to know only whether the gyro is stationary or rotating even before the steady oscillation state, or only a rough detection result even if the S / N is poor and the resolution is low. is there. Even in such a case, according to the present embodiment, even before the steady oscillation state, the system side uses the output voltage VSQ whose sensitivity has been corrected to determine whether it is in a stationary state or a rotating state, or roughly It is possible to determine various detection results and perform various processes.

  As described above, according to the present embodiment, using a vibrator having a high Q value such as a crystal, a stable operation in a normal state can be realized, and a high-speed startup is possible, and both a stable operation and a high-speed startup can be achieved. . In other words, it is possible to use a highly stable crystal resonator even in an application in which the crystal resonator cannot be used because of a long startup time. Further, according to the present embodiment, the circuit can be reduced in size, the cost can be reduced, and the power consumption can be reduced by using the fast start-up.

  As shown in the above equations (4) and (6), the gain KA and KB equations of the drive side gain control circuit 54 (GCAA) and the detection side gain control circuit 80 (GCAB) are substantially the same. . In this case, there is a time lag because the actual amplitude follows the setting of the gain KA of the drive-side gain control circuit 54 due to the Q value of the vibrator. On the other hand, since the setting of the gain KB of the gain control circuit 80 on the detection side is immediately reflected in the amplification of the signal amplitude on the detection side, normal operation can be guaranteed.

4). First Modification FIG. 12A shows a first modification of this embodiment. In the first modification, the detection circuit 60 includes an offset adjustment circuit 90 that performs offset adjustment of a detection signal (gyro signal). The gain control circuit 80 is provided on the upstream side of the offset adjustment circuit 90.

  Here, the offset adjustment circuit 90 includes a D / A conversion circuit 92 and an addition circuit (addition / subtraction circuit) 94. The D / A conversion circuit 92 converts offset (initial offset) adjustment data DDA into an analog offset adjustment voltage VA.

  The adder circuit 94 adds the adjustment voltage VA from the D / A conversion circuit 92 to the voltage of the input signal VS5. The adder circuit 94 includes resistors RE1, RE2, and RE3 provided between the nodes NE5 and NE6, NE1, and NE2, respectively. Also included is an operational amplifier OPE2 whose node NE5 is connected to its inverting input terminal and whose node AGND is connected to its non-inverting input terminal.

  For example, in this embodiment, the output voltage VSQ of the detection device 30 is monitored after the gyro sensor is manufactured. Then, offset adjustment data for making VSQ coincide with the reference output voltage is written in a non-illustrated nonvolatile memory or the like. Then, the adjustment data DDA written in the nonvolatile memory or the like is input to the D / A conversion circuit 92, and the D / A conversion circuit 92 outputs an adjustment voltage VA having an offset corresponding to the DDA. Then, the addition circuit 94 performs adjustment for removing the offset voltage by adding the adjustment voltage VA to the voltage of the input signal VS5. In this case, in FIG. 12A, the offset adjustment circuit 90 is provided on the upstream side of the synchronous detection circuit 100. Since the operational amplifier OPE2 of the offset adjustment circuit 90 is also used as an inverting amplification operational amplifier (OPE in FIG. 4) for the synchronous detection circuit 100, the circuit can be reduced in scale.

  In this embodiment, as shown in FIG. 12A, a gain control circuit 80 is provided on the upstream side of the offset adjustment circuit 90. For example, as described with reference to FIG. 3A, desired signals and unnecessary signals (mechanical leakage and electrostatic leakage) are mixed in the detection signal from the vibrator. Since an unnecessary signal (unnecessary wave) that causes an offset is also approximately proportional to the drive amplitude, the offset may be shifted unless gain adjustment is performed in the same manner as the desired signal. That is, if the gain control circuit 80 is provided on the subsequent stage side of the offset adjustment circuit 90 and the gain is adjusted after the offset adjustment, the offset that should have been adjusted is shifted.

  In this regard, in FIG. 12A, the gain control circuit 80 is provided on the upstream side of the offset adjustment circuit 90, and offset adjustment can be performed with the sensitivity set to the specification sensitivity. Can prevent the problem of end.

  In FIG. 12A, a gain control circuit 80 for adjusting sensitivity is provided on the upstream side of the synchronous detection circuit 100. In this way, gain adjustment is performed in the state of the signal of frequency fd instead of the DC signal. Therefore, the adverse effect of flicker noise (1 / f noise) that decreases as the frequency increases can be minimized. Further, the noise generated in the gain control circuit 80 itself appears in the fd frequency band by synchronous detection as shown in FIG. 3B and can be removed by the filter unit 110. Therefore, the adverse effect of noise generated in the gain control circuit 80 itself can be reduced. Furthermore, since the number of circuit blocks on the front stage side of the gain control circuit 80 is reduced as compared with the case where the gain control circuit is provided on the rear stage side of the filter unit 110, the gain control circuit 80 amplifies the noise of these circuit blocks. Degradation of the S / N ratio due to can be minimized.

  In FIG. 12A, the offset adjustment circuit 90 is provided between the gain control circuit 80 and the synchronous detection circuit 100. However, the offset adjustment circuit is provided downstream of the synchronous detection circuit 100 as shown in FIG. 91 may be provided.

5. Second Modification FIG. 13 shows a second modification of the present embodiment. In the second modification, a determination circuit 120 is further provided for the configuration of FIGS. The determination circuit (monitor circuit) 120 compares the control voltage VC from the drive amplitude detection circuit 52 with the determination voltages Vr1 and Vr2, and at least determination information for informing whether the vibrator 10 is in a steady oscillation state or an oscillation starting process. Output. That is, the reliability of the sensitivity output is invalid / temporarily determined to be valid / valid, and the determination result is output.

  Specifically, the determination circuit 120 compares the control voltage VC with the first determination voltage Vr1. If it is determined that the vibrator 10 is in the steady oscillation state based on the comparison result, the first determination monitor signal DET1 is output to the first output terminal (first pad). That is, the signal DET1 is activated. Further, the control voltage VC is compared with the second determination voltage Vr2. When it is determined that the vibrator 10 is in the oscillation starting process based on the comparison result, the second determination monitor signal DET2 is output to the second output terminal (second pad). That is, the signal DET2 is activated.

  When the signal DET2 becomes active, the switching element SE3 provided at the output of the detection device 30 is connected to the Vnull side. As a result, the output of the detection device 30 is set to the invalid voltage Vnull (a low voltage corresponding to an angular velocity of 0), and the system is notified that the output of the detection device 30 is invalid.

  Alternatively, determination information for notifying that the drive amplitude in the drive circuit 40 does not reach the specification amplitude but sensitivity correction is being performed by the gain control circuit 80 may be output. That is, as such determination information, the third determination monitor signal DET3 is output to the third output terminal.

  For example, as shown in FIG. 14, when the determination circuit 120 determines that the control voltage is VC <Vr2, the determination circuit 120 activates the second determination monitor signal DET2. Thereby, the system side is informed that the vibrator 10 is in the oscillation starting process and the output of the detection device 30 is invalid.

  When it is determined that the control voltage is Vr1−Vr1d <VC <Vr1 + Vr1d, the first determination monitor signal DET1 is activated. Thereby, the system side is informed that the vibrator 10 is in a steady oscillation state (after T2 in FIG. 10A) and the output of the detection device 30 is effective.

  When it is determined that the control voltage is Vr2 <VC <Vr1-Vr1d or VC> Vr1 + Vr1d, the third determination monitor signal DET3 is activated. Thereby, the sensitivity correction is being performed by the gain control circuit 80, and the system side is informed that the output of the detection device 30 is effective for the time being.

  In FIG. 13 and FIG. 14, determination monitor signals DET1, DET2, and DET3 are output to the output terminals (IC pads) as determination information, but the determination information is not limited to this. For example, a register for determination monitoring may be provided in the detection device 30, and an output valid flag corresponding to DET1 and an output invalid flag corresponding to DET2 may be set in this register to transmit the determination information to the system side.

  In FIG. 15, since it is not possible to directly determine that VC <VCmax, a determination voltage Vr2 (Vr2 <VCmax) is prepared. When VC <Vr2, the signal DET2 notifying that the output is invalid is activated because the oscillation is in the starting process and the output of the detection device 30 is still unreliable. That is, it is determined that the period from T0 to T4 in FIG. 15 is the oscillation starting process, and this is transmitted to the system side. In this way, the system side can determine that the output of the detection device 30 is invalid simply by monitoring the signal DET2, and can prevent a situation where an invalid output is taken in.

  In FIG. 15, when VC> Vr2, sensitivity correction is performed, and the signal DET3 notifying that the output of the detection device 30 is valid is activated. That is, in the period from T4 to T2, since sensitivity correction is performed, the sensitivity is equal to the specified sensitivity as indicated by F4 in FIG. However, as shown in FIG. 10A, the drive amplitude does not reach the specification amplitude during the period from T3 to T2 because the vibrator is not in a steady oscillation state. Therefore, the S / N ratio is worse than in the normal state, and the resolution is reduced.

  However, depending on the application, even if the S / N ratio is somewhat deteriorated, there may be a case where it is desired to obtain a temporary angular velocity or a case where it is desired to obtain an output level of 0 point (at rest). In such a case, if the signal DET3 becomes active, the system side can determine that the output of the detection device 30 is valid for the time being, and can perform various processes using the output of the detection device 30. Become.

  In FIG. 15, when VC becomes Vr1, the signal DET1 notifying that the output of the detection device 30 is valid becomes active. That is, in the period after T2, as shown in FIG. 10A, the vibrator 10 is in a steady oscillation state, and the system side is informed that the output of the detection device 30 is in a normal state.

  As described above, in the present embodiment, by providing the detection device 30 with the monitoring function of the oscillation state of the vibrator 10, the convenience on the system side has been greatly improved.

  FIG. 16A illustrates a configuration example of the determination circuit 120. The determination circuit 120 includes comparators CMP1 and CMP2. In the comparator CMP1, the control voltage VC is input to the non-inverting input terminal, and the determination voltage Vr1 is input to the inverting input terminal. Since the comparator CMP1 has a hysteresis characteristic, as shown in FIG. 14, it can be determined whether or not Vr1-Vr1d <VC <Vr1 + Vr1d, and the determination monitor signal DET1 can be output.

  In the comparator CMP2, the control voltage VC is input to its inverting input terminal, and the determination voltage Vr2 is input to its non-inverting input terminal. Therefore, as shown in FIG. 14, it is possible to determine whether or not VC <Vr2 and output the determination monitor signal DET2.

  When the determination monitor signal DET3 is also generated, a logic circuit such as a NOR circuit NOR to which the outputs of the comparators CMP1 and CMP2 are input may be provided as shown in FIG. For example, in FIG. 16B, when the signals DET1 and DET2 are both inactive (1 level), the signal DET3 becomes active and the system side is informed that the output of the detection device 30 is valid for the time being. The

6). Electronic Device FIG. 17 shows a configuration example of a gyro sensor 510 (sensor in a broad sense) including the detection device 30 of this embodiment and an electronic device 500 including the gyro sensor 510. Note that the electronic device 500 and the gyro sensor 510 are not limited to the configuration shown in FIG. 17, and various modifications such as omitting some of the components or adding other components are possible. In addition, as the electronic device 500 of the present embodiment, various devices such as a digital camera, a video camera, a mobile phone, a car navigation system, a robot, a game machine, and a portable information terminal can be considered.

  Electronic device 500 includes a gyro sensor 510 and a processing unit 520. Further, a memory 530, an operation unit 540, and a display unit 550 can be included. A processing unit (CPU, MPU, etc.) 520 performs control of the gyro sensor 510 and the like and overall control of the electronic device 500. The processing unit 520 performs processing based on angular velocity information (physical quantity) detected by the gyro sensor 510. For example, processing for camera shake correction, posture control, GPS autonomous navigation, and the like is performed based on the angular velocity information. A memory (ROM, RAM, etc.) 530 stores a control program and various data, and functions as a work area and a data storage area. The operation unit 540 is for the user to operate the electronic device 500, and the display unit 550 displays various information to the user. According to the detection device 30 of the present embodiment, a small sensor can be adopted as the gyro sensor 510 incorporated in the electronic apparatus 500. Thereby, the electronic device 500 can be reduced in size and cost.

  Although the present embodiment has been described in detail as described above, it will be easily understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention. For example, a term described at least once together with a different term having a broader meaning or the same meaning in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings. All combinations of the present embodiment and the modified examples are also included in the scope of the present invention. Further, the structure of the vibrator and the configurations and operations of the detection device, the drive circuit, the detection circuit, the sensor, and the electronic device are not limited to those described in this embodiment, and various modifications can be made. For example, in the invention that outputs the determination information described with reference to FIG. 13, the method of controlling the gain on the detection side according to the drive amplitude described with reference to FIGS. 1 and 4 may not be employed.

The structural example of the detection apparatus of this embodiment. 2A and 2B are explanatory diagrams of the vibrator. 3A to 3C are explanatory diagrams of the frequency spectrum. 3 shows a detailed configuration example of a detection device. 5A to 5C are configuration examples of an I / V conversion circuit, a differential amplifier circuit, and the like. Configuration example of gain control amplifier. FIG. 7A and FIG. 7B are diagrams showing the relationship of drive amplitude-control voltage and control voltage-gain. FIG. 8A and FIG. 8B are explanatory views of the oscillation process and sensitivity change of the vibrator. Explanatory drawing about a sensitivity. FIGS. 10A and 10B are explanatory diagrams of the oscillation process and sensitivity change of a vibrator having a high Q value. FIG. 11A and FIG. 11B are explanatory diagrams of the gain control method of this embodiment. FIG. 12A and FIG. 12B are configuration examples of the first modification of the present embodiment. The structural example of the 2nd modification of this embodiment. Explanatory drawing of the determination method of the 2nd modification. Explanatory drawing of the determination method of the 2nd modification. FIG. 16A and FIG. 16B are configuration examples of the determination circuit. Configuration examples of electronic devices and gyro sensors.

Explanation of symbols

2, 4 drive terminals, 6, 8 detection terminals, 10 vibrators, 11, 12 drive side vibrators,
16, 17 Detection-side vibrator, 30 detection device, 40 drive circuit, 42 amplification circuit,
43 I / V conversion circuit, 44 phase adjustment circuit, 46 binarization circuit, 50 AGC circuit,
52 drive amplitude detection circuit, 54 gain control circuit, 60 detection circuit, 70 amplification circuit,
72, 74 Q / V conversion circuit, 76 differential amplifier circuit, 80 gain control circuit,
100 synchronous detection circuit, 100 synchronous detection circuit, 110 filter unit,
112 pre-filter, 114 post-filter, 120 judgment circuit,
500 electronic equipment, 510 gyro sensor, 520 processing unit, 530 memory,
540 operation unit, 550 display unit

Claims (15)

A drive circuit that outputs a drive signal to drive the physical quantity transducer;
A detection circuit that receives a detection signal from the physical quantity transducer and detects a desired signal from the detection signal;
The drive circuit is
A drive amplitude detection circuit for detecting a drive amplitude of the physical quantity transducer and outputting a control voltage corresponding to the detected drive amplitude;
The detection circuit includes:
Including a gain control circuit for adjusting the gain of the detection signal;
The gain control circuit includes:
A detection apparatus that adjusts a gain of a detection signal based on the control voltage from the drive amplitude detection circuit. In claim 1,
The gain control circuit includes:
A detection apparatus comprising: adjusting a gain of a detection signal so as to be inversely proportional to a drive amplitude in the drive circuit. In claim 1 or 2,
The gain control circuit includes:
A detection apparatus, wherein sensitivity correction is performed so that the sensitivity of the detection circuit approaches the specification sensitivity before the drive amplitude in the drive circuit reaches the specification amplitude. In claim 3,
The physical quantity transducer is a vibrator;
The gain control circuit includes:
A detection apparatus, wherein sensitivity correction is performed so that the sensitivity of the detection circuit approaches a specification sensitivity in a period before the vibrator enters a steady oscillation state. In any one of Claims 1 thru | or 4,
The detection circuit includes:
Including an offset adjustment circuit for adjusting the offset of the detection signal;
The detection apparatus according to claim 1, wherein the gain control circuit is provided on the upstream side of the offset adjustment circuit. In any one of Claims 1 thru | or 5,
The physical quantity transducer is a vibrator;
A determination circuit that compares the control voltage from the drive amplitude detection circuit with a given determination voltage and outputs determination information notifying at least whether the vibrator is in a steady oscillation state or an oscillation starting process; Detection device. In claim 6,
The determination circuit includes:
When the control voltage is compared with a first determination voltage and it is determined that the vibrator is in a steady oscillation state, a first determination monitor signal is output to a first output terminal, and the control voltage is A detection apparatus that outputs a second determination monitor signal to a second output terminal when it is determined that the vibrator is in an oscillation starting process as compared with a determination voltage of 2. In claim 6 or 7,
The gain control circuit performs sensitivity correction of the detection signal,
The determination circuit includes:
A detection apparatus that outputs determination information notifying that a drive amplitude in the drive circuit does not reach a specification amplitude but sensitivity correction is performed by the gain control circuit. In claim 8,
The determination circuit includes:
When the control voltage is compared with a first determination voltage and it is determined that the vibrator is in a steady oscillation state, a first determination monitor signal is output to a first output terminal, and the control voltage is When the oscillator is determined to be in the oscillation starting process, the second determination monitor signal is output to the second output terminal, and the drive amplitude in the drive circuit is the specified amplitude. However, if it is determined that sensitivity correction is being performed by the gain control circuit, a third determination monitor signal is output to the third output terminal. In any one of Claims 1 thru | or 9,
The drive circuit is
A detection apparatus comprising: a gain control circuit that controls a gain of a drive signal in the drive circuit based on the control voltage from the drive amplitude detection circuit. In any one of Claims 1 thru | or 10.
The detection circuit includes:
An amplification circuit for amplifying a detection signal from the physical quantity transducer;
Including a synchronous detection circuit that performs synchronous detection based on a synchronous signal from the drive circuit;
The detection apparatus, wherein the gain control circuit is provided between the amplification circuit and the synchronous detection circuit. A drive circuit that outputs a drive signal to drive the physical quantity transducer;
A detection circuit that receives a detection signal from the physical quantity transducer and detects a desired signal from the detection signal;
The drive circuit is
A drive amplitude detection circuit for detecting a drive amplitude of the physical quantity transducer and outputting a control voltage corresponding to the detected drive amplitude;
The physical quantity transducer is a vibrator;
A determination circuit that compares the control voltage from the drive amplitude detection circuit with a given determination voltage and outputs determination information notifying at least whether the vibrator is in a steady oscillation state or an oscillation starting process; Detection device. In claim 12,
The determination circuit includes:
When the control voltage is compared with a first determination voltage and it is determined that the vibrator is in a steady oscillation state, a first determination monitor signal is output to a first output terminal, and the control voltage is A detection apparatus that outputs a second determination monitor signal to a second output terminal when it is determined that the vibrator is in an oscillation starting process as compared with a determination voltage of 2. A detection device according to any one of claims 1 to 13,
The physical quantity transducer;
A sensor comprising: A sensor according to claim 14,
A processing unit that performs processing based on detection information of the sensor;
An electronic device comprising:

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