JP6508460B2 - Physical quantity detection circuit, physical quantity detection device, electronic device, and moving body - Google Patents

Description

  The present invention relates to a physical quantity detection circuit, a physical quantity detection device, an electronic device, and a movable body.

  In Patent Document 1, a fault diagnosis signal is input to a transducer diagnostic electrode, a signal based on the fault diagnostic signal is detected from an angular velocity detection electrode of the transducer, and synchronization is performed with a signal of the same frequency as the fault diagnostic signal. An angular velocity sensor capable of detecting wire breakage of a drive system and a detection system by detection is disclosed.

JP 2000-146590 A

  However, in the angular velocity sensor described in Patent Document 1, when an impact is applied to cause the oscillator to generate vibration at a frequency close to its natural frequency, signal saturation occurs in the detection system, and the detection system behaves in an actual manner. There is a problem that an incorrect detection signal different from the above is output, and the processing device that has received the detection signal does not recognize that the signal is an incorrect signal and performs an erroneous process.

  The present invention has been made in view of the above problems, and according to some aspects of the present invention, it is possible to reduce the possibility that an apparatus receiving a detection signal performs an erroneous process. A physical quantity detection circuit and a physical quantity detection device can be provided. Further, according to some aspects of the present invention, it is possible to provide an electronic device and a mobile using the circuit for detecting the physical quantity.

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

Application Example 1
The physical quantity detection circuit according to this application example includes a detection circuit that receives a signal from the physical quantity detection element and outputs a detection signal, and an abnormality diagnosis circuit, and the detection circuit includes at least one amplification circuit. The abnormality diagnosis circuit has a monitor determination circuit that monitors the magnitude of a signal input to a circuit downstream of the amplification circuit.

  For example, the monitoring determination circuit may monitor the magnitude of the output signal of the amplification circuit.

  According to the circuit for detecting physical quantity according to this application example, when an impact causing vibration with a frequency close to the natural frequency is applied to the physical quantity detection element, the physical quantity detection element is superimposed on the output signal of the physical quantity detection element Since the signal increases due to the amplification of the signal by the amplifier circuit, it is possible to diagnose whether the detection signal is erroneous or not by monitoring the magnitude of the signal input to the circuit downstream of the amplifier circuit. Therefore, the device that receives the detection signal can recognize that the detection signal is an erroneous signal based on the diagnosis result, so that the possibility of performing erroneous processing using the detection signal can be reduced. .

Application Example 2
In the physical quantity detection circuit according to the application example, the monitoring determination circuit may monitor saturation of a signal input to a circuit downstream of the amplification circuit.

  “Monitoring saturation” may be monitoring whether or not the output signal of the amplification circuit has reached the maximum value of the output range, or a value slightly lower than the maximum value (for example, maximum It may be to monitor whether 90% of the value has been reached.

  According to the circuit for detecting physical quantity according to this application example, when an impact causing vibration with a frequency close to the natural frequency is applied to the physical quantity detection element, a signal input to the circuit downstream of the amplifier circuit Since it is easy to saturate, it is possible to diagnose whether the detected signal is erroneous or not by monitoring the saturation of the signal.

Application Example 3
In the physical quantity detection circuit according to the application example, one of the amplifier circuits may be an AC amplifier circuit.

  The detection circuit may have a synchronous detection circuit, and the AC amplification circuit may be a circuit preceding the synchronous detection circuit.

  According to the circuit for detecting physical quantity according to this application example, when an impact that causes vibration of relatively high frequency is applied to the physical quantity detection element, the signal superimposed on the output signal of the physical quantity detection element due to the impact is Since the signal amplification by the AC amplification circuit is increased, it is possible to diagnose whether the detection signal is erroneous or not by monitoring the magnitude of the signal input to the circuit downstream of the AC amplification circuit.

Application Example 4
In the physical quantity detection circuit according to the application example, one of the amplifier circuits may be a DC amplifier circuit.

  The DC amplification circuit may be a circuit at a stage before the synchronous detection circuit.

  According to the circuit for detecting physical quantity according to this application example, when an impact causing vibration of relatively low frequency is applied to the physical quantity detection element, the signal superimposed on the output signal of the physical quantity detection element due to the impact is Since the signal amplification by the DC amplification circuit is increased, it is possible to diagnose whether the detection signal is erroneous or not by monitoring the magnitude of the signal input to the circuit downstream of the DC amplification circuit.

Application Example 5
In the physical quantity detection circuit according to the application example, the detection circuit may have a low pass filter at a stage subsequent to the amplification circuit.

  According to the physical quantity detection circuit according to this application example, since the output delay of the low pass filter is relatively large, it is possible to output a signal indicating that the detection signal is erroneous prior to the erroneous detection signal.

Application Example 6
In the physical quantity detection circuit according to the application example, the abnormality diagnosis circuit monitors a plurality of amplification circuits and a plurality of signals input to circuits downstream of the plurality of amplification circuits. And the monitoring determination circuit.

Application Example 7
In the physical quantity detection circuit according to the application example, the abnormality diagnosis circuit may include an OR circuit to which signals from the plurality of monitor determination circuits are input.

  According to the physical quantity detection circuit according to these applications, whether or not the detection signal is erroneous is more monitored by monitoring the magnitude of the signal input to the circuit at the subsequent stage than each of the plurality of amplifier circuits. It can be reliably diagnosed.

Application Example 8
A physical quantity detection device according to the application example includes: a physical quantity detection element; a drive circuit for driving the physical quantity detection element; a detection circuit which receives a signal from the physical quantity detection element and outputs a detection signal; , The detection circuit includes at least one amplification circuit, and the abnormality diagnosis circuit includes a monitoring determination circuit monitoring a magnitude of a signal input to a circuit downstream of the amplification circuit.

  According to the physical quantity detection device according to this application example, when an impact causing vibration with a frequency close to the natural frequency is applied to the physical quantity detection element, a signal superimposed on the output signal of the physical quantity detection element by the impact. Is increased by the amplification of the signal by the amplification circuit, so by monitoring the magnitude of the signal input to the circuit downstream of the amplification circuit, it is possible to diagnose whether the detection signal is erroneous or not. Therefore, the device that receives the detection signal can recognize that the detection signal is an erroneous signal based on the diagnosis result, so that the possibility of performing erroneous processing using the detection signal can be reduced. .

Application Example 9
The electronic device according to this application example includes any of the circuits for detecting physical quantity described above.

Application Example 10
The mobile unit according to this application example includes any of the circuits for detecting physical quantity described above.

  According to these applications, a device for receiving a detection signal uses a physical quantity detection circuit capable of reducing the possibility of erroneous processing, so that, for example, highly reliable electronic equipment and mobile objects are realized. It is also possible.

FIG. 1 is a diagram showing an example of the configuration of a physical quantity detection device of the present embodiment. The top view of the vibrator | oscillator of a vibrator. FIG. 7 is a diagram for describing an operation of a vibrator. FIG. 7 is a diagram for describing an operation of a vibrator. FIG. 2 is a diagram showing an example of the configuration of a drive circuit. FIG. 2 is a view showing an example of the configuration of a detection circuit and an abnormality diagnosis circuit in the first embodiment. FIG. 5 is a diagram showing an example of natural frequencies (resonance frequencies) of physical quantity detection elements. The figure which shows an example of the waveform of an angular velocity signal and a diagnostic signal. FIG. 7 is a view showing an example of the configuration of a detection circuit and an abnormality diagnosis circuit according to a second embodiment. FIG. 7 is a view showing an example of the configuration of a detection circuit and an abnormality diagnosis circuit in a third embodiment. BRIEF DESCRIPTION OF THE DRAWINGS The functional block diagram of the sideslip prevention apparatus which is an example of the electronic device of this embodiment. The figure which shows an example of the mobile body of this embodiment.

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

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

1. Physical quantity detection device 1-1. First embodiment [Configuration of physical quantity detection device]
FIG. 1 is a functional block diagram of a physical quantity detection device (angular velocity detection device) of the present embodiment. The physical quantity detection device 1 of the present embodiment is configured to include a physical quantity detection element (sensor element) 100 that outputs an analog signal related to the physical quantity and a physical quantity detection circuit 200.

  The physical quantity detection element 100 has a vibrating reed in which a drive electrode and a detection electrode are arranged, and generally, the vibrating reed has airtightness in order to reduce the impedance of the vibrating reed as much as possible to enhance the oscillation efficiency. It is sealed in a package. In the present embodiment, the physical quantity detection element 100 has a so-called double T-type vibration piece having two T-type drive vibration arms.

  FIG. 2 is a plan view of the vibrating reed of the physical quantity detection device 100 of the present embodiment. The physical quantity detection element 100 has, for example, a double T-shaped vibrating piece formed of a Z-cut quartz substrate. The vibrating piece made of quartz has an advantage that the detection accuracy of the angular velocity can be enhanced because the fluctuation of the resonant frequency with respect to the temperature change is extremely small. The X axis, the Y axis, and the Z axis in FIG. 2 indicate the axes of the quartz crystal.

  As shown in FIG. 2, in the vibrating bars of the physical quantity detection element 100, driving vibrating arms 101a and 101b extend from the two driving bases 104a and 104b in the + Y axis direction and the −Y axis direction, respectively. Drive electrodes 112 and 113 are formed on the side surface and the top surface of the drive vibration arm 101a, and drive electrodes 113 and 112 are formed on the side surface and the top surface of the drive vibration arm 101b, respectively. The drive electrodes 112 and 113 are connected to the drive circuit 20 via the DS terminal and the DG terminal of the physical quantity detection circuit 200 shown in FIG. 1, respectively.

  The drive base portions 104a and 104b are connected to the rectangular detection base portion 107 via connecting arms 105a and 105b extending in the −X axis direction and the + X axis direction, respectively.

  The detection vibrating arm 102 extends from the detection base 107 in the + Y axis direction and the −Y axis direction. The detection electrodes 114 and 115 are formed on the top surface of the detection vibrating arm 102, and the common electrode 116 is formed on the side surface of the detection vibrating arm 102. The detection electrodes 114 and 115 are connected to the detection circuit 30 via terminals S1 and S2 of the physical quantity detection circuit 200 shown in FIG. 1, respectively. Also, the common electrode 116 is grounded.

  When an AC voltage is applied as a drive signal between the drive electrode 112 and the drive electrode 113 of the drive vibrating arms 101a and 101b, as shown in FIG. 3, the drive vibrating arms 101a and 101b are as shown by arrow B by the reverse piezoelectric effect. In addition, the tips of the two drive vibrating arms 101a and 101b perform bending vibration (excitation vibration) that repeatedly approaches and separates from each other.

In this state, when an angular velocity with the Z axis as the rotation axis is applied to the vibrating reed of the physical quantity detection element 100, the driving vibrating arms 101a and 101b are Coriolis in the direction perpendicular to both the bending vibration direction of the arrow B and the Z axis. Gain the power of As a result, as shown in FIG. 4, the connecting arms 105 a and 105 b vibrate as shown by the arrow C. Then, the detection vibration arm 102 performs bending vibration as shown by an arrow D in conjunction with the vibration (arrow C) of the connecting arms 105a and 105b. The bending vibration of the detection vibrating arm 102 and the bending vibration (excitation vibration) of the driving vibrating arms 101 a and 101 b due to the Coriolis force are out of phase by 90 °.

  By the way, if the magnitude of the vibration energy or the magnitude of the amplitude of the vibration when the drive vibration arms 101a and 101b vibrate in bending (excitation vibration) is equal to that of the two drive vibration arms 101a and 101b, the drive vibration arm 101a The vibration energy of 101 b is well balanced, and in a state where the physical quantity detection element 100 is not subjected to the angular velocity, the detection vibration arm 102 does not bend and vibrate. However, when the balance of the vibrational energy of the two drive vibrating arms 101a and 101b is lost, bending vibration is generated in the detection vibrating arm 102 even in a state where the physical quantity detection element 100 is not subjected to the angular velocity. This bending vibration is called leakage vibration and is bending vibration of arrow D as in the vibration based on the Coriolis force, but in phase with the drive signal.

  Then, an alternating current charge based on these bending vibrations is generated in the detection electrodes 114 and 115 of the detection vibrating arm 102 by the piezoelectric effect. Here, the AC charge generated based on the Coriolis force changes in accordance with the magnitude of the Coriolis force (in other words, the magnitude of the angular velocity applied to the physical quantity detection element 100). On the other hand, the AC charge generated based on the leakage vibration is constant regardless of the magnitude of the angular velocity applied to the physical quantity detection element 100.

  A rectangular weight portion 103 wider than the drive vibrating arms 101a and 101b is formed at the tip of the drive vibrating arms 101a and 101b. By forming the weight portion 103 at the tip of the drive vibrating arms 101a and 101b, the Coriolis force can be increased, and a desired resonance frequency can be obtained with a relatively short vibrating arm. Similarly, at the tip of the detection vibrating arm 102, a weight portion 106 wider than the detection vibrating arm 102 is formed. By forming the weight portion 106 at the tip of the detection vibrating arm 102, the AC charge generated in the detection electrodes 114 and 115 can be increased.

  As described above, the physical quantity detection element 100 detects the AC charge (angular velocity component) based on the Coriolis force with the Z axis as the detection axis and the AC charge (vibration leak component) based on the leak vibration of the excitation vibration. Output via 115.

  Returning to FIG. 1, the physical quantity detection circuit 200 of the present embodiment is configured to include the reference voltage circuit 10, the drive circuit 20, the detection circuit 30, the abnormality diagnosis circuit 40, and the storage unit 50. It may be an integrated circuit (IC: Integrated Circuit). The physical quantity detection circuit 200 of this embodiment may have a configuration in which some of these elements are omitted or changed, or other elements are added.

  The reference voltage circuit 10 generates a constant voltage or a constant current such as a reference voltage (analog ground voltage) from a power supply voltage supplied from the VDD terminal of the physical quantity detection circuit 200, and supplies the constant voltage or the constant current to the drive circuit 20 and the detection circuit 30.

  The drive circuit 20 generates a drive signal for exciting and vibrating the physical quantity detection element 100, and supplies the drive signal to the drive electrode 112 of the physical quantity detection element 100 via the DS terminal. In the drive circuit 20, the oscillation current generated in the drive electrode 113 by the excitation vibration of the physical quantity detection element 100 is input via the DG terminal, and the amplitude level of the drive signal is maintained so that the amplitude of this oscillation current is held constant. Feedback control. The drive circuit 20 also generates a detection signal SDET having the same phase as the drive signal, and outputs the detection signal SDET to the detection circuit 30.

The detection circuit 30 receives the AC charge (detection current) generated in the two detection electrodes 114 and 115 of the physical quantity detection element 100 through the S1 terminal and the S2 terminal, respectively, and uses the detection signal SDET to detect these AC currents. An angular velocity component included in the charge (detection current) is detected, and a detection signal (angular velocity signal) VO of a voltage level corresponding to the magnitude of the angular velocity component is generated and output. The angular velocity signal VO is output to an MCU (Micro Control Unit) 2 (control device) which is an external device of the physical quantity detection circuit 200 via the VOUT terminal of the physical quantity detection circuit 200.

  The abnormality diagnosis circuit 40 monitors the internal signal of the detection circuit 30, diagnoses whether the output signal of the physical quantity detection element 100 is normal or abnormal, and generates a diagnostic signal DIAG indicating whether it is normal or abnormal. Output. In the present embodiment, the diagnostic signal DIAG indicates a normal state when the level is low and indicates an abnormal state when the level is high. The diagnostic signal DIAG is output to the MCU 2 through the DOUT terminal of the physical quantity detection circuit 200.

  The storage unit 50 has a non-volatile memory (not shown), and various trimming data (adjustment data and correction data) for the drive circuit 20 and the detection circuit 30 are stored in the non-volatile memory. The nonvolatile memory can be configured, for example, as a MONOS (Metal Oxide Nitride Oxide Silicon) type memory or an EEPROM (Electrically Erasable Programmable Read-Only Memory). Furthermore, the storage unit 50 has a register (not shown), and various trimmings stored in the non-volatile memory when the physical quantity detection circuit 200 is powered on (when the voltage of the VDD terminal rises from 0 V to a desired voltage) The data may be transferred to and held by the register, and various trimming data held by the register may be supplied to the drive circuit 20 and the detection circuit 30.

[Configuration of drive circuit]
Next, the drive circuit 20 will be described. FIG. 5 is a view showing a configuration example of the drive circuit 20. As shown in FIG. As shown in FIG. 5, the drive circuit 20 of the present embodiment includes an I / V conversion circuit 21, a high pass filter (HPF) 22, a comparator 23, a full wave rectification circuit 24, an integrator 25 and a comparator 26. It is configured. The drive circuit 20 of the present embodiment may be configured such that some of these elements are omitted or changed, or other elements are added.

  The I / V conversion circuit 21 is generated by the excitation vibration of the physical quantity detection element 100, and converts the oscillation current input through the DG terminal into an AC voltage signal.

  The high pass filter 22 removes the offset of the output signal of the I / V conversion circuit 21.

  The comparator 23 compares the voltage of the output signal of the high pass filter 22 with a reference voltage to generate a binarized signal, and when the binarized signal is at high level, turns on the NMOS transistor to output a low level. When the binary signal is at low level, the NMOS transistor is turned off, and the output voltage of the integrator 25 pulled up via the resistor is output as high level. The output signal of the comparator 23 is supplied as a drive signal to the physical quantity detection element 100 via the DS terminal. The physical quantity detection element 100 can be stably oscillated by matching the frequency (drive frequency) of the drive signal with the resonance frequency of the physical quantity detection element 100.

  The full wave rectification circuit 24 rectifies (full wave rectification) the output signal of the I / V conversion circuit 21 and outputs a DC-converted signal.

The integrator 25 integrates and outputs the output voltage of the full-wave rectifier circuit 24 based on the desired voltage VRDR supplied from the reference voltage circuit 10. The output voltage of the integrator 25 becomes lower as the output of the full wave rectification circuit 24 is higher (as the amplitude of the output signal of the I / V conversion circuit 21 is larger). Therefore, the higher the oscillation amplitude, the lower the high level voltage of the output signal (drive signal) of the comparator 23. The smaller the oscillation amplitude, the higher the high level voltage of the output signal (drive signal) of the comparator 23. Therefore, automatic gain control (AGC: Auto Gain Control) is applied to keep the oscillation amplitude constant.

  The comparator 26 amplifies the voltage of the output signal of the high pass filter 22 to generate a binarized signal (square wave voltage signal), and outputs it as a detection signal SDET.

[Configuration of detection circuit and abnormality diagnosis circuit]
Next, the detection circuit 30 and the abnormality diagnosis circuit 40 will be described. FIG. 6 is a view showing a configuration example of the detection circuit 30 and the abnormality diagnosis circuit 40. As shown in FIG. 6, the detection circuit 30 according to the present embodiment includes charge amplifiers 31 and 32, a differential amplification circuit 33, a high pass filter (HPF) 34, an AC amplification circuit 35, a synchronous detection circuit 36, a DC amplification circuit 37, A low pass filter 38 and an output buffer 39 are included. The detection circuit 30 according to the present embodiment may have a configuration in which some of these elements are omitted or changed, or other elements are added.

  An alternating current charge (detection current) including an angular velocity component and a vibration leakage component is input to the charge amplifier 31 from the detection electrode 114 of the vibrating reed of the physical quantity detection device 100 via the S1 terminal. Similarly, alternating charge (detection current) including an angular velocity component and a vibration leakage component is input to the charge amplifier 32 from the detection electrode 115 of the vibrating reed of the physical quantity detection device 100 via the S2 terminal.

  The charge amplifiers 31 and 32 convert the input alternating charge (detection current) into an alternating voltage signal. The AC charge (detection current) input to the charge amplifier 31 and the AC charge (detection current) input to the charge amplifier 32 are 180 ° out of phase with each other, and the phase of the output signal of the charge amplifier 31 and the output signal of the charge amplifier 32 Are out of phase with each other (180 ° out of phase).

  The differential amplifier circuit 33 differentially amplifies the output signal of the charge amplifier 31 and the output signal of the charge amplifier 32. The differential amplifier circuit 33 cancels the in-phase component and adds and amplifies the reverse-phase component.

  The high pass filter 34 removes the DC component contained in the output signal of the differential amplifier circuit 33.

  The AC amplifier circuit 35 outputs an AC voltage signal obtained by amplifying the output signal of the high pass filter 34.

  The synchronous detection circuit 36 synchronously detects an angular velocity component included in the output signal (detected signal) of the AC amplification circuit 35 using the detection signal SDET output from the drive circuit 20. For example, when the detection signal SDET is high level, the synchronous detection circuit 36 selects the output signal of the AC amplification circuit 35 as it is, and when the detection signal SDET is low level, the output signal of the AC amplification circuit 35 is compared to the reference voltage. Thus, the circuit can be configured as a circuit that selects the inverted signal.

  The output signal of the AC amplification circuit 35 includes an angular velocity component and a vibration leakage component. The angular velocity component is in the same phase as the detection signal SDET, whereas the vibration leakage component is in the opposite phase. Therefore, although the angular velocity component is synchronously detected by the synchronous detection circuit 36, the vibration leakage component is not detected.

  The DC amplification circuit 37 amplifies or attenuates the output signal of the synchronous detection circuit 36 to output a signal of a desired voltage level, and the output signal of the DC amplification circuit 37 is input to the low pass filter 38. The DC amplification circuit 37 may be a variable gain amplifier.

The low pass filter 38 removes high frequency components contained in the output signal of the DC amplification circuit 37 and passes signals in the frequency range determined by the specification. The low pass filter 38 may be a switched capacitor filter (SCF). The frequency characteristics of the switched capacitor filter (SCF) are determined by the frequency ratio of the clock signal (not shown) obtained by the stable oscillation of the physical quantity detection element 100 and the capacitance ratio of the capacitor (not shown). There is an advantage that variation in frequency characteristics is extremely small.

  The output signal of the low pass filter 38 is buffered by the output buffer 39 and, if necessary, amplified or attenuated to a signal of a desired voltage level. An output signal of the output buffer 39 is output from the detection circuit 30 as an angular velocity signal VO.

  The detection circuit 30 configured in this way amplifies the minute detection current input from the S1 terminal and the S2 terminal by the differential amplification circuit 33 and the AC amplification circuit 35 at the front stage of the synchronization detection circuit 36, and the synchronization detection circuit The angular velocity signal VO is generated by amplification by the DC amplification circuit 37 after the step 36.

  By the way, as shown in the example of FIG. 7, the physical quantity detection element 100 has a plurality of natural frequencies (resonance frequencies) (a frequency at which the amplitude reaches a peak in FIG. 7). The amplitude of the detection current instantaneously increases when an impact is applied that causes the vibration in the direction shown in FIG. 4 at a frequency close to (approximately equal to) the natural frequency of. Then, in the detection circuit 30, the output voltage of the AC amplification circuit 35 is instantaneously saturated, as a result, the output signal of the DC amplification circuit 37 is also saturated, and an angular velocity signal VO indicating that a large angular velocity is detected instantaneously It will be output. For example, assuming that the physical quantity detection device 1 is attached to a vehicle, not only when a large impact is applied to the vehicle, such as a car collision or a rollover, the stone collides with the vehicle or the vehicle Even when a relatively small impact is applied to the vehicle, such as riding on a curb, the physical quantity detection element 100 vibrates at the natural frequency in the direction shown in FIG. 4, and the amplitude of the detection current may momentarily increase. Therefore, since the angular velocity signal VO is output as if the detection circuit 30 detected a large angular velocity even though a large impact is not actually applied, the MCU 2 uses the angular velocity signal VO to perform erroneous processing ( For example, there is a risk that the air bag may be opened only when the vehicle gets on the curb.

  Therefore, in the present embodiment, as shown in FIG. 6, the abnormality diagnosis circuit 40 monitors the magnitude of a signal (output signal of the AC amplification circuit 35) input to a circuit downstream of the AC amplification circuit 35. A monitoring determination circuit 41 is provided. For example, the monitoring determination circuit 41 may monitor whether the output signal of the AC amplification circuit 35 is higher or lower than a predetermined threshold. In the present embodiment, the monitoring determination circuit 41 monitors saturation of a signal (output signal of the AC amplification circuit 35) input to a circuit downstream of the AC amplification circuit 35. For example, the monitoring determination circuit 41 monitors whether or not the output voltage of the AC amplification circuit 35 has reached the maximum value of the output range, or a value slightly lower than the maximum value of the output range (for example, 90 of the maximum value). Saturation may be monitored by monitoring whether%) is reached. Then, the monitoring determination circuit 41 outputs a signal that is low when the output signal of the AC amplification circuit 35 is not saturated (saturated or near saturated), and is high when saturated. Alternatively, the monitor determination circuit 41 may output a signal that becomes high level when the output signal of the AC amplification circuit 35 is saturated, and returns to low level if it is not saturated for a certain period of time. The abnormality diagnosis circuit 40 outputs the output signal of the monitoring determination circuit 41 as a diagnosis signal DIAG.

FIG. 8 is a diagram showing an example of the waveforms of the angular velocity signal VO and the diagnostic signal DIAG. In the example of FIG. 8, is prior to time t _1, a diagnostic signal DIAG is the low level (voltage level indicating a normal state), MCU 2 performs various processes using the angular velocity signal VO. Time t ₁ ~
next (voltage level indicating an abnormal state) diagnostic signal DIAG output signal of the AC amplifier 35 becomes saturated at a high level at t _3, MCU 2 is an angular velocity signal VO at time _t 1 ~t ₅ Stop the various processes used. At time t _3, the diagnostic signal DIAG goes low no longer in saturation of the output signal of the AC amplifier 35, MCU 2 resumes the various processes using the angular velocity signal VO.

In the present embodiment, the detection circuit 30 includes the low pass filter 38 at a later stage than the AC amplification circuit 35, and the output delay of the low pass filter 38 is relatively large. The diagnostic signal DIAG changes from low level to high level. Therefore, MCU 2 can avoid the diagnostic signal DIAG is after time t ₁ became high, erroneous by stopping the various processes using the angular velocity signal VO processing. On the other hand, before the angular velocity signal VO to return to normal signal, for diagnostic signal DIAG is changed from high level to low level, MCU 2, the diagnostic signal DIAG a certain time from the time t ₃ when returned to the low level (the angular velocity signal VO may be a diagnostic signal time longer than the delay difference DIAG) is the after time t ₅ elapses, to avoid processing the wrong by resuming the various processes using the angular velocity signal VO.

[effect]
As described above, according to the physical quantity detection device 1 (physical quantity detection circuit 200) of the first embodiment, when the physical quantity detection element 100 is subjected to an impact that causes vibration with a frequency close to its natural frequency. Since the signal superimposed on the output signal of the physical quantity detection element 100 due to the shock increases due to the amplification of the signal by the AC amplification circuit 35, the magnitude (for example, saturation) of the output signal of the AC amplification circuit 35 is monitored. Thus, it can be diagnosed whether or not the angular velocity signal VO is incorrect. Therefore, the MCU 2 can recognize that the angular velocity signal VO is an incorrect signal based on the diagnostic signal DIAG, and therefore, the possibility of performing erroneous processing using the angular velocity signal VO can be reduced. In particular, according to the physical quantity detection device 1 (physical quantity detection circuit 200) of the first embodiment, even when an impact that causes vibration of relatively high frequency is applied to the physical quantity detection element 100, the physical quantity is caused by the impact. Since the signal superimposed on the output signal of the detection element 100 is increased by the amplification of the signal by the AC amplification circuit 35, whether the angular velocity signal VO is erroneous or not by monitoring the magnitude of the output signal of the AC amplification circuit 35 Can be diagnosed.

  Further, according to the physical quantity detection device 1 (physical quantity detection circuit 200) of the first embodiment, since the output delay of the low pass filter 38 at a later stage than the AC amplification circuit 35 is relatively large, it precedes the erroneous angular velocity signal VO. Thus, it is possible to output a diagnostic signal DIAG indicating that the angular velocity signal VO is erroneous. Therefore, the MCU 2 can recognize beforehand that the angular velocity signal VO is an incorrect signal based on the diagnostic signal DIAG, so that the possibility of performing erroneous processing using the angular velocity signal VO can be reduced.

1-2. Second Embodiment The physical quantity detection device 1 of the second embodiment is configured to include the physical quantity detection element 100 and the physical quantity detection circuit 200 as in the first embodiment, and the physical quantity detection circuit 200 is the first embodiment. Similar to the embodiment, the reference voltage circuit 10, the drive circuit 20, the detection circuit 30, the abnormality diagnosis circuit 40, and the storage unit 50 are included. However, in the physical quantity detection device 1 of the second embodiment, the configuration of the abnormality diagnosis circuit 40 is different from that of the first embodiment.

  FIG. 9 is a view showing a configuration example of the detection circuit 30 and the abnormality diagnosis circuit 40 in the physical quantity detection device 1 of the second embodiment. Below, the same numerals are given to the same composition as a 1st embodiment, points different from a 1st embodiment are explained, and the explanation which overlaps with a 1st embodiment is omitted.

  As shown in FIG. 9, the configuration of the detection circuit 30 is the same as that of FIG.

  The abnormality diagnosis circuit 40 includes a monitor determination circuit 41, a monitor determination circuit 42, and an OR circuit 44. As in the first embodiment, the monitoring determination circuit 41 is a circuit that monitors the magnitude (saturation) of a signal (output signal of the AC amplification circuit 35) input to a circuit downstream of the AC amplification circuit 35.

  The monitoring determination circuit 42 is a circuit that monitors the magnitude of a signal (output signal of the DC amplification circuit 37) input to a circuit downstream of the DC amplification circuit 37. For example, the monitoring determination circuit 42 may monitor whether the output signal of the DC amplification circuit 37 is higher or lower than a predetermined threshold. In the present embodiment, the monitoring determination circuit 42 monitors saturation of a signal (output signal of the DC amplification circuit 37) input to a circuit downstream of the DC amplification circuit 37. For example, the monitoring determination circuit 42 monitors whether the output voltage of the DC amplification circuit 37 has reached the maximum value of the output range, or a value slightly lower than the maximum value of the output range (for example, 90 of the maximum value). Saturation may be monitored by monitoring whether%) is reached. Then, the monitoring determination circuit 42 outputs a signal that is low when the output signal of the DC amplification circuit 37 is not saturated (saturated or near saturation), and is high when saturated. Alternatively, the monitor determination circuit 42 may output a signal that becomes high level when the output signal of the DC amplification circuit 37 is saturated, and returns to low level if it is not saturated for a certain period of time.

  The OR circuit 44 receives the signal from the monitor determination circuit 41 and the signal from the monitor determination circuit 42, and outputs an OR signal of these signals. That is, the logical sum circuit 44 becomes low level when both of the output signal of the monitor determination circuit 41 and the output signal of the monitor determination circuit 42 are low level (voltage level indicating that it is not saturated state). When the signal and at least one of the output signals of the monitoring and determination circuit 42 are at high level (voltage level indicating saturation), a signal that becomes high level is output. The abnormality diagnosis circuit 40 outputs the output signal of the OR circuit 44 as a diagnosis signal DIAG.

  Also in the present embodiment, the diagnostic signal DIAG indicates a normal state when it is low level and indicates an abnormal state when it is high level, and is output to the MCU 2 via the DOUT terminal of the physical quantity detection circuit 200.

  Further, since the detection circuit 30 has the low-pass filter 38 with a relatively large output delay after the AC amplification circuit 35 and the DC amplification circuit 37, the diagnostic signal DIAG is generated a little before the angular velocity signal VO becomes abnormal. Change from low level to high level. Therefore, the MCU 2 can avoid erroneous processing by stopping various types of processing using the angular velocity signal VO after the diagnostic signal DIAG becomes high level. On the other hand, since the diagnostic signal DIAG changes from high level to low level before the angular velocity signal VO returns to a normal signal, the MCU 2 continues for a fixed time after the diagnostic signal DIAG returns to low level (the angular velocity signal VO and the diagnostic signal An erroneous process can be avoided by resuming various processes using the angular velocity signal VO after the lapse of a time longer than the delay difference of DIAG.

According to the physical quantity detection device 1 (physical quantity detection circuit 200) of the second embodiment, when the physical quantity detection element 100 is subjected to an impact that causes vibration at a frequency close to its natural frequency, the physical quantity is caused by the impact. Since the signal superimposed on the output signal of the detection element 100 is increased by amplification of the signal by at least one of the AC amplification circuit 35 and the DC amplification circuit 37, the magnitude (eg, saturation) of the output signal of the AC amplification circuit 35 and DC By monitoring the magnitude (for example, saturation) of the output signal of the amplification circuit 37, it can be diagnosed whether or not the angular velocity signal VO is erroneous. Therefore, the MCU 2 can recognize that the angular velocity signal VO is an incorrect signal based on the diagnostic signal DIAG, and therefore, the possibility of performing erroneous processing using the angular velocity signal VO can be reduced. In particular, according to the physical quantity detection device 1 (physical quantity detection circuit 200) of the second embodiment, when an impact that causes vibration of a relatively high frequency is applied to the physical quantity detection element 100, the physical quantity is caused by the impact. When the signal superimposed on the output signal of the detection element 100 is increased by amplification of the signal by the AC amplification circuit 35 and the physical quantity detection element 100 is subjected to an impact that causes vibration of a relatively low frequency, the impact Since the signal superimposed on the output signal of the physical quantity detection element 100 is increased by the amplification of the signal by the DC amplification circuit 37, it can be diagnosed more reliably whether the angular velocity signal VO is erroneous or not.

  Also, according to the physical quantity detection device 1 (physical quantity detection circuit 200) of the second embodiment, the output delay of the low pass filter 38 at a later stage than the AC amplification circuit 35 and the DC amplification circuit 37 is relatively large. Prior to the angular velocity signal VO, a diagnostic signal DIAG can be output indicating that the angular velocity signal VO is incorrect. Therefore, the MCU 2 can recognize beforehand that the angular velocity signal VO is an incorrect signal based on the diagnostic signal DIAG, so that the possibility of performing erroneous processing using the angular velocity signal VO can be reduced.

1-3. Third Embodiment The physical quantity detection device 1 of the third embodiment is configured to include the physical quantity detection element 100 and the physical quantity detection circuit 200 as in the first and second embodiments. Similarly to the first and second embodiments, the reference voltage circuit 10, the drive circuit 20, the detection circuit 30, the abnormality diagnosis circuit 40, and the storage unit 50 are configured. However, in the physical quantity detection device 1 of the third embodiment, the configuration of the abnormality diagnosis circuit 40 is different from that of the first embodiment and the second embodiment.

  FIG. 10 is a diagram showing a configuration example of the detection circuit 30 and the abnormality diagnosis circuit 40 in the physical quantity detection device 1 of the third embodiment. In the following, the same reference numerals are given to the same components as the first embodiment or the second embodiment, and the points different from the first embodiment or the second embodiment will be described, and the same components as the first embodiment or the second embodiment overlap. The explanation is omitted.

  As shown in FIG. 10, the configuration of the detection circuit 30 is the same as that of FIG.

  The abnormality diagnosis circuit 40 includes a monitor determination circuit 41, a monitor determination circuit 42, a monitor determination circuit 43, and an OR circuit 44. As in the first embodiment, the monitoring determination circuit 41 is a circuit that monitors the magnitude (saturation) of a signal (output signal of the AC amplification circuit 35) input to a circuit downstream of the AC amplification circuit 35. Further, as in the second embodiment, the monitor determination circuit 42 is a circuit that monitors the magnitude (saturation) of a signal (output signal of the DC amplification circuit 37) input to a circuit downstream of the DC amplification circuit 37. is there.

  The monitor determination circuit 43 is a circuit that monitors the magnitude of a signal (output signal of the differential amplifier circuit 33) input to a circuit that is subsequent to the differential amplifier circuit 33. For example, the monitoring determination circuit 43 may monitor whether the output signal of the differential amplifier circuit 33 is higher or lower than a predetermined threshold. In the present embodiment, the monitoring and determination circuit 43 monitors saturation of a signal (output signal of the differential amplifier circuit 33) input to a circuit downstream of the differential amplifier circuit 33. For example, the monitor determination circuit 43 monitors whether or not the output voltage of the differential amplification circuit 33 has reached the maximum value of the output range, or a value slightly lower than the maximum value of the output range (for example, Saturation may be monitored by monitoring whether 90% has been reached. Then, the monitor determination circuit 43 outputs a signal that is low when the output signal of the differential amplifier circuit 33 is not saturated (saturated or near saturation), and is high when saturated. Alternatively, the monitor determination circuit 43 may output a signal that becomes high level when the output signal of the differential amplifier circuit 33 is saturated, and returns to low level if it is not saturated for a predetermined time.

  The OR circuit 44 receives the signal from the monitoring determination circuit 41, the signal from the monitoring determination circuit 42, and the signal from the monitoring determination circuit 43, and outputs an OR signal of these signals. That is, when the output signal of the monitor determination circuit 41, the output signal of the monitor determination circuit 42, and the output signal of the monitor determination circuit 43 are both low level (voltage level indicating that the state is not saturated), the OR circuit 44 is low level. And at least one of the output signal of the monitor determination circuit 41, the output signal of the monitor determination circuit 42, and the output signal of the monitor determination circuit 43 is at a high level (a voltage level indicating that the state is saturated). Output The abnormality diagnosis circuit 40 outputs the output signal of the OR circuit 44 as a diagnosis signal DIAG.

  Also in the present embodiment, the diagnostic signal DIAG indicates a normal state when it is low level and indicates an abnormal state when it is high level, and is output to the MCU 2 via the DOUT terminal of the physical quantity detection circuit 200.

  In addition, since the detection circuit 30 has the low-pass filter 38 with a relatively large output delay behind the differential amplifier circuit 33, the AC amplifier circuit 35, and the DC amplifier circuit 37, the angular velocity signal VO becomes abnormal. Before the diagnostic signal DIAG changes from low level to high level. Therefore, the MCU 2 can avoid erroneous processing by stopping various types of processing using the angular velocity signal VO after the diagnostic signal DIAG becomes high level. On the other hand, since the diagnostic signal DIAG changes from high level to low level before the angular velocity signal VO returns to a normal signal, the MCU 2 continues for a fixed time after the diagnostic signal DIAG returns to low level (the angular velocity signal VO and the diagnostic signal An erroneous process can be avoided by resuming various processes using the angular velocity signal VO after the lapse of a time longer than the delay difference of DIAG.

  According to the physical quantity detection device 1 (physical quantity detection circuit 200) of the second embodiment, when the physical quantity detection element 100 is subjected to an impact that causes vibration at a frequency close to its natural frequency, the physical quantity is caused by the impact. Since the signal superimposed on the output signal of the detection element 100 is increased by amplification of the signal by at least one of the differential amplifier circuit 33, the AC amplifier circuit 35 and the DC amplifier circuit 37, the magnitude of the output signal of the differential amplifier circuit 33 By monitoring the magnitude (for example, saturation) of the output signal of the AC amplification circuit 35 (for example, saturation) and the magnitude (for example, saturation) of the output signal of the DC amplification circuit 37, the angular velocity signal VO erroneously It can be diagnosed whether it is Therefore, the MCU 2 can recognize that the angular velocity signal VO is an incorrect signal based on the diagnostic signal DIAG, and therefore, the possibility of performing erroneous processing using the angular velocity signal VO can be reduced.

  In particular, according to the physical quantity detection device 1 (physical quantity detection circuit 200) of the second embodiment, when an impact that causes vibration of a relatively high frequency is applied to the physical quantity detection element 100, the physical quantity is caused by the impact. When the signal superimposed on the output signal of the detection element 100 is increased by amplification of the signal by the AC amplification circuit 35 and the physical quantity detection element 100 is subjected to an impact that causes vibration of a relatively low frequency, the impact Since the signal superimposed on the output signal of the physical quantity detection element 100 is increased by the amplification of the signal by the DC amplification circuit 37, it can be diagnosed more reliably whether the angular velocity signal VO is erroneous or not.

  Further, according to the physical quantity detection device 1 (physical quantity detection circuit 200) of the second embodiment, the output delay of the low pass filter 38 at the later stage than the differential amplification circuit 33, the AC amplification circuit 35 and the DC amplification circuit 37 is compared. Because of this, it is possible to output a diagnostic signal DIAG indicating that the angular velocity signal VO is incorrect prior to the erroneous angular velocity signal VO. Therefore, the MCU 2 can recognize beforehand that the angular velocity signal VO is an incorrect signal based on the diagnostic signal DIAG, so that the possibility of performing erroneous processing using the angular velocity signal VO can be reduced.

2. Electronic Device FIG. 11 is a functional block diagram of a skid prevention device which is an example of the electronic device. The anti-slip device 300 shown in FIG. 11 includes an angular velocity sensor 310, an acceleration sensor 320, a vehicle speed sensor 330, a steering angle sensor 340, a control unit (MCU) 350 and a brake device 360. It is attached to the vehicle.

  The control unit (MCU) 350 outputs the output signal of the angular velocity sensor 310 (information of the angular velocity of the vehicle), the output signal of the acceleration sensor 320 (information of the acceleration of the vehicle), the output signal of the vehicle speed sensor 330 (information of the velocity of the vehicle) The steering angle sensor 340 (information on the angle of the steering wheel or tire of the vehicle) is acquired, and the brake device 360 is controlled to maintain the posture of the vehicle.

  For example, as the angular velocity sensor 310, the physical quantity detection device 1 of each of the above-described embodiments is applied, or as the angular velocity detection circuit 312 included in the angular velocity sensor 310, the physical quantity detection circuit 200 of each of the above embodiments By applying the method, the possibility that the control device (MCU) 350 performs an erroneous process can be reduced, and a highly reliable sideslip prevention device 300 can be realized.

  Note that, for example, the physical quantity detection device 1 of each of the above-described embodiments is applied as the acceleration sensor 320, or the physical quantity detection of each of the above-described embodiments is used as an acceleration detection circuit (not shown) included in the acceleration sensor 320. Circuit 200 can also be applied.

  As electronic devices to which the physical quantity detection device 1 or physical quantity detection circuit 200 of each embodiment described above can be applied, various electronic devices other than the side slip prevention device 300 can be considered. For example, personal computers (for example, mobile personal computers) Computers, laptop personal computers, tablet personal computers), mobile terminals such as smartphones and mobile phones, digital cameras, inkjet discharge devices (for example, inkjet printers), storage area network devices such as routers and switches, local areas Network equipment, equipment for mobile terminal base station, television, video camera, video recorder, car navigation device, air bag control device, real time clock device, pager , Electronic organizer (including communication function), electronic dictionary, calculator, electronic game machine, game controller, word processor, workstation, videophone, television monitor for crime prevention, electronic binoculars, POS terminal, medical equipment (such as electronic thermometer, Blood pressure monitor, blood glucose meter, electrocardiogram measurement device, ultrasonic diagnostic device, electronic endoscope), fish finder, various measurement devices, instruments (for example, vehicle, aircraft, vessel instruments), flight simulator, head mounted display Motion trace, motion tracking, motion controller, PDR (pedestrian position and orientation measurement), and the like.

3. Mobile Body FIG. 12 is a diagram (top view) showing an example of the mobile body of the present embodiment. The moving body 400 shown in FIG. 12 is configured to include physical quantity detection devices 410, 420, 430, controllers 440, 450, 460, a battery 470, and a navigation device 480. In the mobile object of the present embodiment, a part of the components (each part) of FIG. 12 may be omitted, or another component may be added.

  The physical quantity detection devices 410, 420, 430, the controllers 440, 450, 460 and the navigation device 480 operate with the power supply voltage supplied from the battery 470.

The controllers 440, 450, and 460 use various or all of the physical quantity signals output from the physical quantity detection devices 410, 420, and 430, respectively, to control various types of attitude control system, anti-rollover system, brake system, air bag system, etc. Take control.

  The navigation device 480 displays the position, time, and other various information of the mobile unit 400 on the display based on the output information of the built-in GPS receiver (not shown). In addition, the navigation device 480 incorporates the physical quantity detection apparatus 490, and even when the GPS radio wave does not reach, the position and orientation of the moving body 400 are calculated based on the output signal of the physical quantity detection apparatus 490, and necessary information Continue to display

  The physical quantity detection devices 410, 420, 430, and 490 are devices that output signals (physical quantity signals) of levels according to the detected physical quantities, and are, for example, an angular velocity sensor, an acceleration sensor, a velocity sensor, an inclinometer, etc. .

  For example, the physical quantity detection device 1 according to each of the above-described embodiments is applied as the physical quantity detection apparatus 410, 420, 430, 490, or a physical quantity detection circuit (not shown) included in the physical quantity detection apparatus 410, 420, 430, 490 By applying the circuit 200 for detecting the physical quantity according to each of the above-described embodiments, the possibility of the controller 440, 450, 460 or the navigation device 480 performing an erroneous process is reduced, and a highly reliable mobile object is realized. be able to.

  As such a mobile body 400, various mobile bodies can be considered, for example, an automobile (including an electric car), an aircraft such as a jet plane or a helicopter, a ship, a rocket, a satellite, and the like.

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

  For example, in the above-described second embodiment (FIG. 9), the monitor determination circuit 41 and the OR circuit 44 may be eliminated from the abnormality diagnosis circuit 40, and the output signal of the monitor determination circuit 42 may be used as the diagnostic signal DIAG. Further, for example, in the third embodiment (FIG. 9) described above, either one of the monitoring determination circuit 41 and the monitoring determination circuit 42 may be deleted from the abnormality diagnosis circuit 40 or the monitoring determination circuit from the abnormality diagnosis circuit 40. 41, the monitoring determination circuit 42 and the logical sum circuit 44 may be deleted, and the output signal of the monitoring determination circuit 43 may be used as the diagnostic signal DIAG.

In each embodiment described above, the angular velocity detection apparatus including the physical quantity detection device 100 for detecting the angular velocity has been described as an example, but the present invention relates to a physical quantity detection apparatus including physical quantity detection elements for detecting various physical quantities. Can also be applied. The physical quantity detected by the physical quantity detection element is not limited to the angular velocity, but may be angular acceleration, acceleration, velocity, force or the like. Also, the vibrating reed of the physical quantity detection element need not be a double T type, and may be, for example, a tuning fork type or a comb tooth type, or a sound piece type of triangular prism, square prism, cylinder or the like It is also good. Also, as the material of the vibrating reed of the physical quantity detection element, instead of quartz (SiO ₂ ), for example, piezoelectric single crystals such as lithium tantalate (LiTaO ₃ ) or lithium niobate (LiNbO ₃ ) or lead zirconate titanate A piezoelectric material such as piezoelectric ceramics such as (PZT) may be used, or a silicon semiconductor may be used. Also, for example, a structure in which a piezoelectric thin film such as zinc oxide (ZnO) or aluminum nitride (AlN) sandwiched between drive electrodes is disposed on part of the surface of a silicon semiconductor may be used. The physical quantity detection element is not limited to the piezoelectric element, and may be a dynamic element, an electrostatic capacitance type, an eddy current type, an optical element, a strain gauge type vibration element or the like. Alternatively, the system of the physical quantity detection element is not limited to the vibration system, and may be, for example, an optical system, a rotary system, or a fluid system.

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

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

Reference Signs List 1 physical quantity detection device, 2 MCU, 10 reference voltage circuit, 20 drive circuit, 21 feedback oscillation circuit, 21 I / V conversion circuit (current-voltage conversion circuit), 22 high pass filter, 23 comparator, 24 full wave rectification circuit, 25 integrator, 26 comparator, 30
Detection circuit 31, 32 charge amplifier, 33 differential amplification circuit, 34 high pass filter, 35 AC amplification circuit, 36 synchronous detection circuit, 37 DC amplification circuit, 38 low pass filter, 39 output buffer, 40 abnormality diagnosis circuit, 41, 42 , 43 supervisory judgment circuit, 44 logical sum circuit, 50 storage unit, 100 physical quantity detection elements, 101a to 101b
Drive vibration arm, 102 detection vibration arm, 103 weight portion, 104a to 104b drive base, 105a to 105b connection arm, 106 weight portion, 107 detection base, 112 to 113 drive electrode, 114 to 115 detection electrode, 116 common electrode , 300 sideslip prevention device, 310 angular velocity sensor, 312 angular velocity detection circuit, 320 acceleration sensor, 330 vehicle speed sensor, 340 steering angle sensor, 350 control unit (MCU), 360 brake device, 400 moving body, 410, 420, 430 physical quantity Detection device, 440, 450, 460 controller, 470 battery, 480 navigation device, 490 physical quantity detection device

Claims (9)

A detection circuit which receives a signal from a physical quantity detection element and outputs a detection signal;
And an abnormality diagnosis circuit,
The detection circuit includes an AC amplification circuit, a synchronous detection circuit downstream of the AC amplification circuit, a DC amplification circuit downstream of the synchronous detection circuit, and a low pass filter downstream of the DC amplification circuit. And have
The abnormality diagnosis circuit includes: a first monitor determination circuit monitoring a magnitude of a signal input to the synchronous detection circuit; and a second monitor determination circuit monitoring a magnitude of a signal input to the low pass filter. Physical quantity detection circuit. The first monitoring and determination circuit monitors saturation of a signal input to the synchronous detection circuit ;
The physical quantity detection circuit according to claim 1, wherein the second monitoring and determination circuit monitors saturation of a signal input to the low pass filter . 3. The physical quantity detection circuit according to claim 1, wherein the abnormality diagnosis circuit includes an OR circuit to which a signal from the first monitoring and determination circuit and a signal from the second monitoring and determination circuit are input.   The detection circuit includes a differential amplifier circuit and a high pass filter at a stage subsequent to the differential amplifier circuit.
  The AC amplification circuit is located after the high pass filter,
  The physical quantity detection circuit according to claim 1, wherein the abnormality diagnosis circuit has a third monitoring and determination circuit that monitors the magnitude of a signal input to the high pass filter.   The physical quantity detection circuit according to claim 4, wherein the third monitoring and determination circuit monitors saturation of a signal input to the high pass filter.   The abnormality diagnosis circuit includes an OR circuit to which a signal from the first monitoring and determination circuit, a signal from the second monitoring and determination circuit, and a signal from the third monitoring and determination circuit are input.
The circuit for detecting a physical quantity according to item 4 or 5. A physical quantity detection element,
A drive circuit for driving the physical quantity detection element;
A detection circuit which receives a signal from the physical quantity detection element and outputs a detection signal;
And an abnormality diagnosis circuit,
The detection circuit includes an AC amplification circuit, a synchronous detection circuit downstream of the AC amplification circuit, a DC amplification circuit downstream of the synchronous detection circuit, and a low pass filter downstream of the DC amplification circuit. And have
The abnormality diagnosis circuit includes: a first monitor determination circuit monitoring a magnitude of a signal input to the synchronous detection circuit; and a second monitor determination circuit monitoring a magnitude of a signal input to the low pass filter. Having a physical quantity detection device. An electronic device comprising the physical quantity detection circuit according to any one of claims 1 to 6 . A moving body comprising the circuit for detecting a physical quantity according to any one of claims 1 to 6 .