Physical quantity detection circuit and physical quantity detection device

Abstract

To provide a physical quantity detection circuit capable of reducing the possibility of erroneously diagnosing a failure when an abnormal signal generated by resonance or the like of a physical quantity detection element is input.SOLUTION: A physical quantity detection signal output circuit that includes an amplification circuit that amplifies a signal output from a physical quantity detection element that detects a physical quantity and outputs a physical quantity detection signal corresponding to the physical quantity, a failure diagnosis signal output circuit that outputs a failure diagnosis signal based on an output signal of at least a part of amplifiers among a plurality of amplifiers included in the amplification circuit, a failure diagnosis circuit that performs failure diagnosis based on the failure diagnosis signal and outputs a failure flag indicating a diagnosis result, and a failure diagnosis circuit that compares a level of a signal output from each of the plurality of amplifiers with each of a plurality of set detection levels, A mask signal output circuit that outputs a mask signal based on a comparison result; and an invalidation determination circuit that invalidates the failure flag based on the mask signal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a physical quantity detection circuit and a physical quantity detection device. [Background technology]

[0002] Currently, physical quantity detection devices capable of detecting various physical quantities, such as gyro sensors that detect angular velocity and acceleration sensors that detect acceleration, are widely used in a variety of systems and electronic devices. In recent years, in order to achieve high reliability in systems that use physical quantity detection devices, methods have been proposed for diagnosing whether or not a failure has occurred in the physical quantity detection device.

[0003] For example, Patent Document 1 describes a physical quantity detection device that diagnoses faults in parallel with detecting a physical quantity. In the physical quantity detection device described in Patent Document 1, a physical quantity detection circuit applies a drive signal to a drive electrode of a physical quantity detection element to cause two drive vibration arms to flexurally vibrate. When a physical quantity is applied, the two detection vibration arms flexurally vibrate, generating first and second physical quantity components of opposite phases in the two detection electrodes. The first and second physical quantity components are differentially amplified and then synchronously detected to generate a physical quantity detection signal. Furthermore, the physical quantity detection circuit adds the first and second electrostatic leakage components of the same phase that propagate from the drive electrode to the two detection electrodes via the first and second electrostatic coupling capacitances, and then synchronously detects the sum to generate an electrostatic leakage signal. Fault diagnosis is performed based on the vibration leakage signal. According to the physical quantity detection device described in Patent Document 1, if the wiring connecting the physical quantity detection element and the physical quantity detection circuit is disconnected, the magnitude of the electrostatic leakage signal falls outside a predetermined range, enabling fault diagnosis. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-140589 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in conventional physical quantity detection devices, when resonance occurs in the physical quantity detection element due to the application of mechanical shock or vibration, an abnormal signal is temporarily input to the physical quantity detection circuit, and the physical quantity detection device may be erroneously diagnosed as faulty even when it is not actually faulty. [Means for solving the problem]

[0006] One aspect of the physical quantity detection circuit according to the present invention is a physical quantity detection signal output circuit including an amplifier circuit that amplifies a signal output from a physical quantity detection element that detects a physical quantity, and outputs a physical quantity detection signal corresponding to the physical quantity; a fault diagnosis signal output circuit that outputs a fault diagnosis signal based on output signals of at least some of the amplifiers included in the amplifier circuit; a fault diagnosis circuit that performs a fault diagnosis based on the fault diagnosis signal and outputs a fault flag indicating the diagnosis result; a mask signal output circuit that compares the level of the signal output from each of the plurality of amplifiers with each of a plurality of set detection levels and outputs a mask signal based on the comparison result; an invalidation determination circuit that invalidates the failure flag based on the mask signal; Equipped with.

[0007] One aspect of the physical quantity detection device according to the present invention is a semiconductor device including one aspect of the physical quantity detection circuit; the physical quantity detection element; a package that accommodates the physical quantity detection element and the semiconductor device; Equipped with. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a functional block diagram of the physical quantity detection device. [Figure 2] FIG. 2 is a plan view of a vibrating element of the physical quantity detection element. [Figure 3] FIG. 2 is a diagram showing a configuration example of a driver circuit. [Figure 4] FIG. 2 is a diagram showing a configuration example of a detection circuit. [Figure 5] 3A and 3B are diagrams showing examples of waveforms of various signals with respect to physical quantity components; [Figure 6] 5A and 5B are diagrams showing examples of waveforms of various signals with respect to electrostatic leakage components; [Figure 7] 5A and 5B are diagrams showing examples of waveforms of various signals for vibration leakage components. [Figure 8] FIG. 2 is a diagram showing an example of the configuration of a mask signal output circuit. [Figure 9] 10 is a diagram showing an example of the correspondence relationship between the logical level of a comparison result signal and the logical level of a mask signal; [Figure 10] 5A and 5B are diagrams showing examples of waveforms of various signals in response to an abnormal signal. [Figure 11] 5A and 5B are diagrams showing examples of waveforms of various signals in response to an abnormal signal. [Figure 12] 5A and 5B are diagrams showing examples of waveforms of various signals in response to an abnormal signal. [Figure 13] 5A and 5B are diagrams showing examples of waveforms of various signals in response to an abnormal signal. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Note that the embodiments described below do not unduly limit the content of the present invention as defined in the claims. Furthermore, not all of the configurations described below are necessarily essential components of the present invention.

[0010] In the following, a physical quantity detection device that detects angular velocity as a physical quantity, that is, an angular velocity detection device, will be described as an example.

[0011] 1.Configuration of the physical quantity detection device Fig. 1 is a functional block diagram of a physical quantity detection device of this embodiment. As shown in Fig. 1, the physical quantity detection device 1 of this embodiment includes a physical quantity detection element 100 that detects a physical quantity, a semiconductor device 200 including a physical quantity detection circuit 210, and a package 300 that houses the physical quantity detection element 100 that detects the physical quantity and the semiconductor device 200. The semiconductor device 200 is realized, for example, by a one-chip integrated circuit. The package 300 is, for example, a ceramic package.

[0012] The physical quantity detection element 100 has a vibrating element on which a drive electrode and a detection electrode are arranged, and generally, the vibrating element is sealed in an airtight package in order to minimize the impedance of the vibrating element and increase oscillation efficiency. In this embodiment, the physical quantity detection element 100 has a so-called double T-shaped vibrating element having two T-shaped drive vibrating arms.

[0013] Fig. 2 is a plan view of a vibrating element of the physical quantity detection element 100 of this embodiment. The physical quantity detection element 100 has, for example, a double-T-shaped vibrating element formed from a Z-cut quartz crystal substrate. A vibrating element made of quartz crystal has an advantage in that it can improve the detection accuracy of angular velocity because the resonant frequency fluctuates very little with temperature changes. Note that the X-axis, Y-axis, and Z-axis in Fig. 2 represent the axes of the quartz crystal.

[0014] 2, the vibrating element of the physical quantity detection element 100 has two driving vibration arms 101a and 101b extending in the +Y-axis direction and the -Y-axis direction from two driving bases 104a and 104b, respectively. Driving electrodes 112 and 113 are formed on the side and top surface of the driving vibration arm 101a, respectively, and driving electrodes 113 and 114 are formed on the side and top surface of the driving vibration arm 101b, respectively. 2 is formed. The driving electrode 112 is connected to the DG terminal of the semiconductor device 200 shown in FIG. 1 by a wiring (not shown), and the driving electrode 113 is connected to the DS terminal of the semiconductor device 200 shown in FIG. 1 by a wiring (not shown).

[0015] The driving bases 104a and 104b are connected to a rectangular detecting base 107 via connecting arms 105a and 105b extending in the -X-axis direction and the +X-axis direction, respectively.

[0016] The detection vibrating arm 102 extends in the +Y-axis direction and the −Y-axis direction from the detection base 107. Detection electrodes 114 and 115 are formed on the upper surface of the detection vibrating arm 102, and a 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 the S1 terminal and S2 terminal of the semiconductor device 200 shown in FIG. 1, respectively. The common electrode 116 is also grounded.

[0017] When an AC voltage is applied as a drive signal DRV between the drive electrodes 112 and 113 of the drive vibration arms 101a and 101b, the tips of the two drive vibration arms 101a and 101b undergo bending vibration in which they repeatedly approach and move away from each other in the A direction and the A' direction due to the inverse piezoelectric effect. Hereinafter, the bending vibration of the drive vibration arms 101a and 101b may also be referred to as "excitation vibration."

[0018] In this state, when an angular velocity about the Z axis is applied to the vibrating arms of the physical quantity detection element 100, the drive vibrating arms 101a and 101b receive a Coriolis force in a direction perpendicular to both the direction of the bending vibration and the Z axis. As a result, the two connecting arms 105a and 105b vibrate in directions B and B', which are opposite to each other. At this time, the two detection vibrating arms 102 vibrate in directions C and C', which are opposite to each other, in order to maintain balance. The bending vibration of the detection vibrating arm 102 caused by this Coriolis force and the bending vibration of the drive vibrating arms 101a and 101b are out of phase with each other by 90°.

[0019] Then, due to the piezoelectric effect, AC charges based on these bending vibrations are generated in the detection electrodes 114 and 115 of the detection vibration arm 102. Here, the AC charges generated based on the Coriolis force change depending on the magnitude of the Coriolis force, that is, the magnitude of the angular velocity applied to the physical quantity detection element 100.

[0020] A rectangular weight portion 103 that is wider than the drive vibration arms 101a and 101b is formed at the tip of the drive vibration arms 101a and 101b. By forming the weight portion 103 at the tip of the drive vibration arms 101a and 101b, the Coriolis force is increased and a desired resonance frequency can be obtained with a relatively short vibration arm. Similarly, a weight portion 106 that is wider than the detection vibration arm 102 is formed at the tip of the detection vibration arm 102. By forming the weight portion 106 at the tip of the detection vibration arm 102, the AC charge generated in the detection electrodes 114 and 115 can be increased.

[0021] In addition, the AC frequency components contained in the drive signal DRV supplied to the drive electrode 113 are propagated to the detection electrodes 114, 115 via the first electrostatic coupling capacitance C1 between the drive electrode 113 and the detection electrode 114 and the second electrostatic coupling capacitance C2 between the drive electrode 113 and the detection electrode 115, and AC charges based on these frequency components are generated. However, as will be described later, these AC charges are not erroneously detected as angular velocity.

[0022] Incidentally, if the magnitude of the vibration energy or the magnitude of the vibration amplitude when the drive vibration arms 101a and 101b are flexurally vibrating is equal between the two drive vibration arms 101a and 101b, the vibration energy of the drive vibration arms 101a and 101b is balanced, and the detection vibration arm 102 does not flexurally vibrate when no angular velocity is applied to the physical quantity detection element 100. However, if the balance of the vibration energy of the two drive vibration arms 101a and 101b is lost, the physical quantity Even when no angular velocity is applied to the detection element 100, bending vibration occurs in the detection vibration arm 102. This bending vibration is called leakage vibration, and is a bending vibration in the C and C' directions, similar to the vibration based on the Coriolis force, and AC charges due to the leakage vibration are generated in the detection electrodes 114 and 115. Since the leakage vibration is out of phase with the vibration based on the Coriolis force by 90°, as will be described later, this AC charge is not erroneously detected as an angular velocity, but in order to improve the detection accuracy of the angular velocity, it is preferable that the leakage vibration does not occur.

[0023] For example, by tuning the weights of the four weights 103 so that the vibration energies of the two drive vibration arms 101a are equal, the vibration energies of the two drive vibration arms 101b are equal, and the sum of the vibration energies of the two drive vibration arms 101a and the sum of the vibration energies of the two drive vibration arms 101b are equal, it is possible to almost completely prevent leakage vibration. Tuning the weight of the weight 103 can be performed, for example, by irradiating the weight 103 with a laser to remove a portion of the weight 103. Therefore, if the physical quantity detection element 100 is normal, leakage vibration hardly occurs. However, if the physical quantity detection element 100 fails, for example, if a crack or the like occurs in at least one of the drive vibration arms 101a, 101b and the detection vibration arm 102, the balance of the vibration energies of the drive vibration arms 101a, 101b is disrupted, causing leakage vibration. Therefore, if the physical quantity detection element 100 fails, the physical quantity detection element 100 will output AC charges from the detection electrodes 114 and 115 due to the leakage vibration.

[0024] As described above, the physical quantity detection element 100 is a double-T gyro sensor element, and outputs, from the detection electrodes 114 and 115, AC charges based on the detected physical quantity, AC charges based on the drive signal DRV propagating via the first electrostatic coupling capacitance C1 and the second electrostatic coupling capacitance C2, and AC charges based on leakage vibration. Hereinafter, the AC charges based on the physical quantity will be referred to as "physical quantity components," the AC charges based on the drive signal DRV propagating via the first electrostatic coupling capacitance C1 and the second electrostatic coupling capacitance C2 will be referred to as "electrostatic leakage components," and the AC charges based on leakage vibration will be referred to as "vibration leakage components." In this embodiment, the physical quantity detected by the physical quantity detection element 100 is an angular velocity corresponding to the Coriolis force.

[0025] 1 , the physical quantity detection circuit 210 includes a reference voltage circuit 10, a drive circuit 20, a detection circuit 30, a selector 40, an analog-to-digital conversion circuit 41, an analog-to-digital conversion circuit 42, an oscillation circuit 50, a digital signal processing circuit 51, a control circuit 60, a fault diagnosis circuit 61, a fault diagnosis circuit 62, a mask signal output circuit 70, an invalidation determination circuit 80, an interface circuit 90, and a storage unit 91. Note that the physical quantity detection circuit 210 may have a configuration in which some of these elements are omitted or modified, or in which other elements are added.

[0026] The reference voltage circuit 10 generates a constant voltage or a constant current, such as a reference voltage which is an analog ground voltage, based on the power supply voltage and ground voltage supplied from the VDD terminal and VSS terminal of the semiconductor device 200, and supplies these to the drive circuit 20 and the detection circuit 30.

[0027] The drive circuit 20 applies a drive signal DRV including a first frequency component for driving the physical quantity detection element 100 to the drive electrode 113 of the physical quantity detection element 100 via the DS terminal. The physical quantity detection element 100 is excited to oscillate by the drive signal DRV. The drive circuit 20 receives an oscillation current generated in the drive electrode 112 by the excitation oscillation of the physical quantity detection element 100 via the DG terminal, and feedback controls the amplitude level of the drive signal DRV so that the amplitude of the oscillation current is kept constant. The drive circuit 20 also generates a detection signal SDET in phase with the drive signal DRV, a detection signal QDET having a frequency twice the frequency of the detection signal SDET, and a detection signal VDET out of phase with the drive signal DRV by 90°, and outputs these to the detection circuit 30. The detection signal SDET is an example of a "first detection signal," the detection signal QDET is an example of a "second detection signal," and the detection signal VDET is an example of a "third detection signal."

[0028] The detection circuit 30 outputs physical quantity detection signals SA1O and SA2O corresponding to the physical quantities detected by the physical quantity detection element 100 based on a first physical quantity component included in a first signal output from the detection electrode 114 of the physical quantity detection element 100 and a second physical quantity component included in a second signal output from the detection electrode 115 of the physical quantity detection element 100. The first signal is an AC charge input via the S1 terminal of the semiconductor device 200, and the second signal is an AC charge input via the S2 terminal of the semiconductor device 200. The detection circuit 30 detects physical quantity components based on the first physical quantity component included in the first signal and the second physical quantity component included in the second signal using the detection signal SDET, and generates and outputs the physical quantity detection signals SA1O and SA2O, which are analog signals with voltage levels corresponding to the magnitudes of the detected physical quantity components. The detection electrode 114 is an example of a "first detection electrode," and the detection electrode 115 is an example of a "second detection electrode."

[0029] The detection circuit 30 outputs an electrostatic leakage detection signal QAO based on a first electrostatic leakage component included in the first signal and a second electrostatic leakage component included in the second signal. The drive signal DRV output from the drive circuit 20 includes a second frequency component having a frequency different from the first frequency component. The first electrostatic leakage component is a component resulting from the second frequency component propagating to the detection electrode 114 via a first electrostatic coupling capacitance C1 between the drive electrode 113 and the detection electrode 114 of the physical quantity detection element 100. Similarly, the second electrostatic leakage component is a component resulting from the second frequency component propagating to the detection electrode 115 via a second electrostatic coupling capacitance C2 between the drive electrode 113 and the detection electrode 115 of the physical quantity detection element 100. In this embodiment, the frequency of the second frequency component is twice the frequency of the first frequency component, and as will be described later, is a frequency component generated when the drive circuit 20 generates the drive signal DRV. The detection circuit 30 uses the detection signal QDET to detect an electrostatic leakage component based on a first electrostatic leakage component contained in the first signal and a second electrostatic leakage component contained in the second signal, and generates and outputs an electrostatic leakage detection signal QAO, which is an analog signal with a voltage level according to the magnitude of the detected electrostatic leakage component.

[0030] Furthermore, the detection circuit 30 outputs a vibration leakage detection signal VAO based on a first vibration leakage component included in a first signal output from the detection electrode 114 of the physical quantity detection element 100 and a second vibration leakage component included in a second signal output from the detection electrode 115 of the physical quantity detection element 100. The first vibration leakage component and the second vibration leakage component are components based on vibration of the physical quantity detection element 100. As described above, if the physical quantity detection element 100 is normal, almost no leakage vibration occurs, so the first signal contains almost no first vibration leakage component and the second signal contains almost no second vibration leakage component. On the other hand, if the physical quantity detection element 100 fails, leakage vibration occurs, so the first signal contains the first vibration leakage component and the second signal contains the second vibration leakage component. The detection circuit 30 uses the detection signal VDET to detect a vibration leakage component based on the first vibration leakage component contained in the first signal and the second vibration leakage component contained in the second signal, and generates and outputs a vibration leakage detection signal VAO, which is an analog signal with a voltage level according to the magnitude of the detected vibration leakage component.

[0031] The storage unit 91 has a nonvolatile memory (not shown), and the nonvolatile memory stores various trimming data for the drive circuit 20 and the detection circuit 30. The nonvolatile memory may be configured as, for example, a MONOS-type memory or an EEPROM. MONOS stands for Metal Oxide Nitride Oxide Silicon. EEPROM stands for Electrically Erasable Programmable Read-Only Memory. The storage unit 91 may also have a register (not shown), and may be configured such that when the semiconductor device 200 is powered on, that is, when the voltage at the VDD terminal rises from 0 V to a desired voltage, the various trimming data stored in the nonvolatile memory is transferred to and held in the register, and the various trimming data held in the register is supplied to the drive circuit 20 and the detection circuit 30.

[0032] The oscillator circuit 50 generates a master clock signal MCLK. The oscillation circuit 50 supplies the master clock signal MCLK to the digital signal processing circuit 51 and the fault diagnosis circuits 61 and 62. The oscillation circuit 50 also divides the frequency of the master clock signal MCLK to generate the clock signal ADCLK, and supplies the clock signal ADCLK to the analog-to-digital conversion circuits 41 and 42. The oscillation circuit 50 may generate the master clock signal MCLK by, for example, a ring oscillator or a CR oscillation circuit.

[0033] The selector 40 selects the static leakage detection signal QAO and the vibration leakage detection signal VAO in a time-division manner in response to a control signal output from the control circuit 60, and outputs the selected signal to the analog / digital conversion circuit .

[0034] The analog / digital conversion circuit 41 operates based on the clock signal ADCLK, and converts the physical quantity detection signals SA1O, SA2O, which are analog signals output from the detection circuit 30, into physical quantity detection signals SD1O, SD2O, which are digital signals, and outputs them.

[0035] The analog / digital conversion circuit 42 operates based on the clock signal ADCLK, and converts the electrostatic leak detection signal QAO and the vibration leak detection signal VAO, which are analog signals output in a time-division manner from the selector 40, into the electrostatic leak detection signal QDO and the vibration leak detection signal VDO, which are digital signals, and outputs them.

[0036] The digital signal processing circuit 51 operates based on the master clock signal MCLK, performs predetermined arithmetic processing such as a difference calculation on the physical quantity detection signals SD1O and SD2O output from the analog / digital conversion circuit 41, and outputs the physical quantity detection signal SDO obtained by the arithmetic processing.

[0037] The fault diagnosis circuit 61 operates based on the master clock signal MCLK and performs fault diagnosis on the physical quantity detection device 1 based on the electrostatic leakage detection signal QDO. The fault diagnosis circuit 61 then outputs a fault flag QF indicating whether the physical quantity detection device 1 is faulty. In the physical quantity detection device 1, the AC charge based on the drive signal DRV propagating to the detection electrodes 114, 115 via the first electrostatic coupling capacitance C1 and the second electrostatic coupling capacitance C2 is constant. Therefore, if the two wires connecting the detection electrodes 114, 115 to the S1 terminal and the S2 terminal of the semiconductor device 200 are normal, the value of the electrostatic leakage detection signal QDO falls within a predetermined first range. On the other hand, if at least one of the two wires connecting the detection electrodes 114, 115 to the S1 terminal and the S2 terminal is disconnected, the value of the electrostatic leakage detection signal QDO falls outside the first range. Therefore, the fault diagnosis circuit 61 may diagnose that the physical quantity detection device 1 is faulty if the value of the electrostatic leakage detection signal QDO does not fall within the first range. For example, the first range may be set to include a predetermined value that is assumed in design when the physical quantity detection device 1 is normal, and also to include a range that may vary from the predetermined value due to changes over time. The first range may be fixed or variable. For example, the first range may be variably set according to a value stored in a register that is included in the storage unit 91 and that can be rewritten from outside the semiconductor device 200.

[0038] The fault diagnosis circuit 62 operates in response to the master clock signal MCLK, and performs fault diagnosis of the physical quantity detection device 1 based on the vibration leakage detection signal VDO. The fault diagnosis circuit 62 then outputs a fault flag VF indicating whether or not the physical quantity detection device 1 has failed. If the physical quantity detection device 1 is normal, leakage vibration hardly occurs, and the value of the vibration leakage detection signal VDO falls within a predetermined second range. In contrast, if the physical quantity detection element 100 fails, for example, because part of the physical quantity detection element 100 is broken, leakage vibration occurs, and the value of the vibration leakage detection signal VDO falls outside the second range. Therefore, the fault diagnosis circuit 62 may diagnose that the physical quantity detection device 1 has failed when the value of the vibration leakage detection signal VDO does not fall within the second range. For example, the second range is a range that is assumed in design when the physical quantity detection device 1 is normal. The second range may be set to include a predetermined value that is set to a predetermined value, and a range that can vary from the predetermined value over time. The second range may be fixed or variable. For example, the second range may be set variably according to a value stored in a register that is included in the storage unit 91 and that can be rewritten from outside the semiconductor device 200.

[0039] The mask signal output circuit 70 operates in response to the master clock signal MCLK, and generates and outputs a mask signal MSK based on the logic levels of the signals S1O, S2O, P2O, and FDO, which are internal signals of the detection circuit 30. Details of the signals S1O, S2O, P2O, and FDO and the mask signal MSK will be described later.

[0040] The invalidation determination circuit 80 includes an AND circuit 81, an AND circuit 82, and a NOT circuit 83, and invalidates the fault flags QF and VF based on the mask signal MSK. The NOT circuit 83 outputs a signal obtained by inverting the logical level of the mask signal MSK. The AND circuit 81 receives the fault flag QF and the output signal of the NOT circuit 83, and outputs a fault diagnosis result signal QFX. Specifically, when the output signal of the NOT circuit 83 is at a high level, the AND circuit 81 outputs the fault flag QF as the fault diagnosis result signal QFX, and when the output signal of the NOT circuit 83 is at a low level, the AND circuit 81 outputs a low-level signal as the fault diagnosis result signal QFX.

[0041] The AND circuit 82 receives the fault flag VF and the output signal of the NOT circuit 83, and outputs a fault diagnosis result signal VFX. Specifically, when the output signal of the NOT circuit 83 is at a high level, the AND circuit 82 outputs the fault flag VF as the fault diagnosis result signal VFX, and when the output signal of the NOT circuit 83 is at a low level, the AND circuit 82 outputs a low-level signal as the fault diagnosis result signal VFX.

[0042] Therefore, when the mask signal MSK is at a low level, the invalidation determination circuit 80 outputs the fault flags QF and VF as the fault diagnosis result signals QFX and VFX, respectively, and when the mask signal MSK is at a high level, it outputs low-level signals as the fault diagnosis result signals QFX and VFX. In this way, when a high-level mask signal MSK is input, the invalidation determination circuit 80 invalidates the fault flags QF and VF.

[0043] The control circuit 60 operates in response to the master clock signal MCLK, and generates a control signal that controls the operation of the selector 40, and enable signals EN1 and EN2 for respectively operating the fault diagnosis circuits 61 and 62. Specifically, the enable signal EN1 is made active to operate the fault diagnosis circuit 61 only during the period when the analog-to-digital conversion circuit 42 outputs the static leakage detection signal QDO, and the enable signal EN2 is made active to operate the fault diagnosis circuit 62 only during the period when the analog-to-digital conversion circuit 42 outputs the vibration leakage detection signal VDO.

[0044] The interface circuit 90 performs processing to output the physical quantity detection signal SDO and fault flags QF, VF, etc. output from the digital signal processing circuit 51 to the MCU 5 in response to a request from the MCU 5, which is an external device of the semiconductor device 200. MCU is an abbreviation for Micro Control Unit. Note that the interface circuit 90 may also perform processing to output the electrostatic leakage detection signal QDO and vibration leakage detection signal VDO output from the analog-to-digital conversion circuit 42 to the MCU 5 in response to a request from the MCU 5. In this case, the physical quantity detection circuit 210 may not have the fault diagnosis circuits 61, 62, and the MCU 5 may perform fault diagnosis similar to that of the fault diagnosis circuits 61, 62, based on the electrostatic leakage detection signal QDO and vibration leakage detection signal VDO.

[0045] In addition, the interface circuit 90 reads data stored in the nonvolatile memory or register of the storage unit 91 and outputs it to the MCU 5 in response to a request from the MCU 5, and writes data input from the MCU 5 to the nonvolatile memory or register of the storage unit 91. For example, the MCU 5 may perform a process of writing values ​​for setting the first range and the second range described above into a predetermined register.

[0046] The interface circuit 90 is, for example, an interface circuit for an SPI bus, and receives the selection signal, clock signal, and data signal transmitted from the MCU 5 via the SS terminal, SCLK terminal, and SI terminal of the semiconductor device 200, respectively, and outputs the data signal to the MCU 5 via the SO terminal of the semiconductor device 200. SPI is an abbreviation for Serial Peripheral Interface. The interface circuit 90 can also interface with various buses other than the SPI bus, for example, an I 2 It may also be an interface circuit compatible with the I / F bus. 2 C stands for Inter-Integrated Circuit.

[0047] In the physical quantity detection device 1 of the present embodiment configured as described above, the physical quantity detection element 100 outputs a first signal which is an AC charge generated in the detection electrode 114 and a second signal which is an AC charge generated in the detection electrode 115, and the physical quantity detection circuit 210 generates a physical quantity detection signal SDO corresponding to the physical quantity detected by the physical quantity detection element 100, based on the first and second signals output from the physical quantity detection element 100. Furthermore, the physical quantity detection circuit 210 generates fault diagnosis result signals QFX, VFX which indicate the presence or absence of a fault in the physical quantity detection device 1, based on the first and second signals output from the physical quantity detection element 100.

[0048] 2. Drive circuit configuration Fig. 3 is a diagram showing an example of the configuration of the drive circuit 20. As shown in Fig. 3, the drive circuit 20 includes a current-voltage conversion circuit 21, a full-wave rectification circuit 22, an auto gain control circuit 23, a drive signal generation circuit 24, a phase shift circuit 25, a buffer circuit 26a, a buffer circuit 26b, an FLL circuit 27, a phase adjustment circuit 28, and a frequency divider circuit 29.

[0049] An oscillation current generated in the drive electrode 112 by the excitation vibration of the physical quantity detection element 100 is input to the current-voltage conversion circuit 21 via the DG terminal and converted into an AC voltage signal IVO by the current-voltage conversion circuit 21. The AC voltage signal IVO output from the current-voltage conversion circuit 21 is input to the full-wave rectifier circuit 22, the drive signal generation circuit 24, the phase shift circuit 25, and the buffer circuit 26a.

[0050] The full-wave rectifier circuit 22 performs full-wave rectification on the output signal IVO of the current-voltage converter circuit 21 and outputs a DC signal.

[0051] The auto gain control circuit 23 amplifies the output signal of the full-wave rectifier circuit 22 and outputs a signal of a predetermined voltage. The auto gain control circuit 23 controls the amplification gain in accordance with the magnitude of the output signal of the full-wave rectifier circuit 22 so that the output signal remains constant at the predetermined voltage.

[0052] The drive signal generation circuit 24 outputs a drive signal DRV obtained by binarizing the output signal IVO of the current-voltage conversion circuit 21. The high-level voltage of the drive signal DRV is the voltage of the output signal of the auto gain control circuit 23, and is constant at a predetermined voltage. The drive signal DRV is supplied to the drive electrode 113 of the physical quantity detection element 100 via the DS terminal. The physical quantity detection element 100 can continue to vibrate excitedly by being supplied with the drive signal DRV. Furthermore, by keeping the high-level voltage of the drive signal DRV constant, the drive vibration arms 101a and 101b of the physical quantity detection element 100 can obtain a constant vibration velocity. Therefore, the vibration velocity that generates the Coriolis force becomes constant, and sensitivity can be made more stable.

[0053] The fundamental frequency of the drive signal DRV generated in this way coincides with the frequency f of the bending vibration of the drive vibration arms 101a and 101b of the physical quantity detection element 100. In addition, the full-wave rectifier circuit 22 The second frequency component of frequency 2f is generated by full-wave rectification by the rectifier and is superimposed on the high-level voltage of the drive signal DRV. Therefore, the drive signal DRV includes a first frequency component of frequency f and a second frequency component of frequency 2f.

[0054] The phase shift circuit 25 outputs a signal whose phase is advanced by 90° from the output signal IVO of the current-voltage conversion circuit 21. The phase shift circuit 25 may be an all-pass filter including an amplifier, a resistor, and a capacitor. The buffer circuit 26a outputs a detection signal SDET that is in phase with the signal IVO. The buffer circuit 26b outputs a detection signal VDET that is in phase with the output signal of the phase shift circuit 25. A filter may be provided between the output of the current-voltage conversion circuit 21 and the input of the buffer circuit 26a.

[0055] The FLL circuit 27 converts the detection signal SDET into a clock signal VCO having n times the frequency and outputs it. FLL is an abbreviation for Frequency Locked Loop. The phase adjustment circuit 28 adjusts the phase of the clock signal VCO so that the rising edge of the clock signal VCO output from the FLL circuit 27 aligns with the rising edge of the detection signal SDET. The frequency divider circuit 29 divides the clock signal VCO and outputs a detection signal QDET having twice the frequency of the detection signal SDET.

[0056] The detection signal SDET is a square wave voltage signal with a frequency f, the detection signal QDET is a square wave voltage signal with a frequency 2f, and the detection signal VDET is a square wave voltage signal with a frequency f that is 90° ahead of the phase of the detection signal SDET. The detection signals SDET, QDET, and VDET are supplied to the detection circuit 30.

[0057] 3.Detection circuit configuration Fig. 4 is a diagram showing an example of the configuration of the detection circuit 30. As shown in Fig. 4, the detection circuit 30 includes Q / V amplifiers 31A and 31B, a programmable gain amplifier 32, an adder circuit 33, synchronous detection circuits 35A and 35B, and smoothing circuits 36A and 36B.

[0058] A first signal is input to the Q / V amplifier 31A via the S1 terminal. As described above, the first signal is an AC charge generated in the detection electrode 114 of the physical quantity detection element 100, and includes a first physical quantity component and a first electrostatic leakage component.

[0059] The second signal is input to the Q / V amplifier 31B via the S2 terminal. As described above, the second signal is an AC charge generated in the detection electrode 115 of the physical quantity detection element 100, and includes a second physical quantity component and a second electrostatic leakage component.

[0060] 2, when an angular velocity is applied to the physical quantity detection element 100, the detection vibrating arm 102 on which the detection electrode 114 is formed and the detection vibrating arm 102 on which the detection electrode 115 is formed flexurally vibrate in opposite directions to each other so as to maintain balance. Therefore, the first physical quantity component included in the first signal and the second physical quantity component included in the second signal are out of phase with each other. Here, the fact that the first physical quantity component included in the first signal and the second physical quantity component included in the second signal are out of phase with each other means not only a case where the phase difference between the two physical quantity components is exactly 180°, but also a case where the phase difference between the two physical quantity components has a slight difference from 180° due to a manufacturing error of the physical quantity detection element 100, an error in the delay time of the signal propagation path, etc.

[0061] In this embodiment, the first electrostatic leakage component contained in the first signal and the second electrostatic leakage component contained in the second signal are in phase with each other. Here, the first electrostatic leakage component contained in the first signal and the second electrostatic leakage component contained in the second signal being in phase with each other means not only when the phase difference between the two electrostatic leakage components is exactly 0°, but also when the phase difference between the two electrostatic leakage components is different from 0° due to a manufacturing error of the physical quantity detection element 100, an error in the delay time of the signal propagation path, etc. This also includes cases where there are slight differences.

[0062] When the physical quantity detection element 100 fails, the first signal further includes a first vibration leakage component, and the second signal further includes a second vibration leakage component. In this embodiment, when the physical quantity detection element 100 fails, the first vibration leakage component included in the first signal and the second vibration leakage component included in the second signal are in phase with each other. Here, the first vibration leakage component included in the first signal and the second vibration leakage component included in the second signal being in phase with each other means not only a case where the phase difference between the two vibration leakage components is exactly 0°, but also a case where the phase difference between the two vibration leakage components has a slight difference from 0° due to a manufacturing error of the physical quantity detection element 100, an error in the delay time of the signal propagation path, etc.

[0063] The Q / V amplifier 31A amplifies a first signal input from the detection electrode 114 of the physical quantity detection element 100, and the Q / V amplifier 31B amplifies a second signal input from the detection electrode 115 of the physical quantity detection element 100. Specifically, the Q / V amplifier 31A amplifies the first signal by a reference voltage V generated by the reference voltage circuit 10. ref The Q / V amplifier 31B converts the second signal into an AC voltage signal S1O based on the reference voltage V ref is converted into an AC voltage signal S2O based on the reference voltage and output.

[0064] The programmable gain amplifier 32 receives a differential signal pair consisting of the output signal S1O of the Q / V amplifier 31A and the output signal S2O of the Q / V amplifier 31B, amplifies the difference between the output signal S1O of the Q / V amplifier 31A and the output signal S2O of the Q / V amplifier 31B, and outputs a differential signal pair consisting of signals P1O and P2O.

[0065] Because the first vibration leakage component contained in the first signal and the second vibration leakage component contained in the second signal are in phase with each other, the vibration leakage component is attenuated by the programmable gain amplifier 32. Therefore, even if the physical quantity detection element 100 fails, the influence of the vibration leakage component on the physical quantity component is reduced in the output signal of the programmable gain amplifier 32. Note that, in order to substantially eliminate the influence of the vibration leakage component on the physical quantity component in the output signal of the programmable gain amplifier 32, it is preferable that the difference between the first vibration leakage component and the second vibration leakage component is substantially zero. The difference between the first vibration leakage component and the second vibration leakage component being substantially zero not only means that the difference is exactly zero, but also means that the difference has a slight difference from zero due to the minimum adjustment resolution of the first vibration leakage component or the second vibration leakage component, or that the measured value has a slight difference from zero due to a measurement error in the difference between the first vibration leakage component and the second vibration leakage component.

[0066] The synchronous detection circuit 35A synchronously detects the output signals P1O, P2O of the programmable gain amplifier 32. Specifically, the synchronous detection circuit 35A uses the output signals P1O, P2O of the programmable gain amplifier 32 as detection target signals, performs synchronous detection using the detection signal SDET, and outputs a differential signal pair consisting of signals SZ1O, SZ2O. The synchronous detection circuit 35A extracts physical quantity components contained in the output signals P1O, P2O of the programmable gain amplifier 32. For example, the synchronous detection circuit 35A detects the voltage level of the detection signal SDET when the voltage level of the detection signal SDET is equal to or exceeds a reference voltage V ref When the signal SZ1O is higher than the reference voltage V, the signal P1O is selected as the signal SZ1O and the signal P2O is selected as the signal SZ2O. ref , the switch circuit may select the signal P2O as the signal SZ1O and select the signal P1O as the signal SZ2O.

[0067] The smoothing circuit 36A smoothes the output signals SZ1O and SZ2O of the synchronous detection circuit 35A into DC voltage signals and outputs a differential signal pair. The output signals of the smoothing circuit 36A are output from the detection circuit 30 as physical quantity detection signals SA1O and SA2O.

[0068] The Q / V amplifiers 31A and 31B and the programmable gain amplifier 32 constitute an amplifier circuit 34 that amplifies the signal output from the physical quantity detection element 100. In other words, the amplifier circuit 34 includes a plurality of amplifiers, namely, the Q / V amplifiers 31A and 31B and the programmable gain amplifier 32. The Q / V amplifier 31A is an example of a "first amplifier," the Q / V amplifier 31B is an example of a "second amplifier," and the programmable gain amplifier 32 is an example of a "third amplifier."

[0069] Furthermore, the amplifier circuit 34, the synchronous detection circuit 35A, and the smoothing circuit 36A constitute a physical quantity detection signal output circuit 37 that outputs physical quantity detection signals SA1O, SA2O corresponding to the physical quantity detected by the physical quantity detection element 100. The physical quantity detection signal output circuit 37 amplifies the difference between the first signal and the second signal input from the detection electrodes 114, 115 of the physical quantity detection element 100, respectively, using the Q / V amplifiers 31A, 31B and the programmable gain amplifier 32, synchronously detects the output signals P1O, P2O of the programmable gain amplifier 32 based on the detection signal SDET, and outputs the physical quantity detection signals SA1O, SA2O based on the signals SZ1O, SZ2O obtained by synchronous detection.

[0070] The adder circuit 33 outputs a signal FDO obtained by adding the output signal S1O of the Q / V amplifier 31A and the output signal S2O of the Q / V amplifier 31B. As described above, the first physical quantity component contained in the first signal and the second physical quantity component contained in the second signal are out of phase with each other, so the physical quantity components are attenuated by the adder circuit 33. On the other hand, the first electrostatic leakage component contained in the first signal and the second electrostatic leakage component contained in the second signal are in phase with each other, so the electrostatic leakage component is amplified by the adder circuit 33. Similarly, the first vibration leakage component contained in the first signal and the second vibration leakage component contained in the second signal are in phase with each other, so the vibration leakage component is amplified by the adder circuit 33.

[0071] The synchronous detection circuit 35B synchronously detects the output signal FDO of the adder circuit 33. Specifically, the synchronous detection circuit 35B uses the output signal FDO of the adder circuit 33 as a signal to be detected, performs synchronous detection using the detection signal QDET, and outputs a signal QZO. The synchronous detection circuit 35B extracts the electrostatic leakage component contained in the output signal FDO of the adder circuit 33. For example, the synchronous detection circuit 35B detects, as the signal QZO, the voltage level of the detection signal QDET being higher than the reference voltage V ref When the voltage level of the detection signal QDET is higher than the reference voltage V ref When the output signal FDO of the adder circuit 33 is lower than the reference voltage V ref Alternatively, the switch circuit may select an inverted signal for the input signal.

[0072] The smoothing circuit 36B smoothes the output signal QZO of the synchronous detection circuit 35B into a DC voltage signal, which is output from the detection circuit 30 as the static leakage detection signal QAO.

[0073] The synchronous detection circuit 35C uses the output signal FDO of the adder circuit 33 as a signal to be detected, performs synchronous detection using the detection signal VDET, and outputs a signal VZO. The synchronous detection circuit 35B extracts the vibration leakage component contained in the output signal FDO of the adder circuit 33. For example, the synchronous detection circuit 35C detects, as the signal VZO, the voltage level of the detection signal VDET being higher than the reference voltage V ref When the voltage level of the detection signal VDET is higher than the reference voltage V ref When the output signal FDO of the adder circuit 33 is lower than the reference voltage V ref Alternatively, the switch circuit may select an inverted signal for the input signal.

[0074] The smoothing circuit 36C smoothes the output signal VZO of the synchronous detection circuit 35C into a DC voltage signal. The output signal of the smoothing circuit 36C is output from the detection circuit 30 as the vibration leakage detection signal VAO.

[0075] The adder circuit 33, synchronous detection circuits 35B, 35C, and smoothing circuits 36B, 36C constitute a fault diagnosis signal output circuit 38 that outputs electrostatic leakage detection signal QAO and vibration leakage detection signal VAO, which are fault diagnosis signals, based on output signals from at least some of the Q / V amplifiers 31A, 31B and programmable gain amplifier 32, which are multiple amplifiers included in the amplifier circuit 34. The fault diagnosis signal output circuit 38 synchronously detects signal FDO, which is obtained by adding output signal S1O of Q / V amplifier 31A and output signal S2O of Q / V amplifier 31B using adder circuit 33, based on detection signal QDET using synchronous detection circuit 35B, and outputs electrostatic leakage detection signal QAO, which is a fault diagnosis signal, based on signal QZO obtained by synchronous detection. Furthermore, the fault diagnosis signal output circuit 38 synchronously detects the signal FDO obtained by adding the output signal S1O of the Q / V amplifier 31A and the output signal S2O of the Q / V amplifier 31B using the adder circuit 33 based on the detection signal VDET using the synchronous detection circuit 35C, and outputs the vibration leakage detection signal VAO, which is a fault diagnosis signal, based on the signal VZO obtained by synchronous detection.

[0076] The selector 40, analog-to-digital conversion circuit 42, and fault diagnosis circuits 61 and 62 shown in FIG. 1 function as a fault diagnosis circuit that performs fault diagnosis based on the electrostatic leakage detection signal QAO and the vibration leakage detection signal VAO, which are fault diagnosis signals, and outputs fault flags QF and VF that indicate the diagnosis results.

[0077] Fig. 5 is a diagram showing an example of waveforms of various signals corresponding to physical quantity components contained in the AC charge output from the physical quantity detection element 100. In Fig. 5, for the waveform of each signal, the horizontal axis represents time and the vertical axis represents voltage. Note that Fig. 5 shows an example in which a constant angular velocity is applied to the physical quantity detection element 100.

[0078] The output signal IVO of the current-voltage conversion circuit 21 is a reference voltage V ref It is a signal of constant frequency f centered on .

[0079] The drive signal DRV is in phase with the signal IVO and has a constant amplitude V cThe drive signal DRV includes a first frequency component with a frequency f, and a second frequency component with a frequency 2f superimposed on a high-level voltage.

[0080] The detection signal SDET is in phase with the drive signal DRV and has a constant amplitude V d is a square wave voltage signal.

[0081] The detection signal VDET has a phase lead of 90° with respect to the drive signal DRV, and its amplitude is a constant value V d Therefore, the phase of the detection signal VDET is shifted by 90° from the phase of the detection signal SDET.

[0082] The detection signal QDET has a frequency twice that of the drive signal DRV and a constant amplitude V d Therefore, the frequency of the detection signal QDET is twice the frequency of the detection signal SDET.

[0083] The first physical quantity component included in the output signal S1O of the Q / V amplifier 31A is a reference voltage V ref It is a signal of constant frequency f centered on .

[0084] The second physical quantity component included in the output signal S2O of the Q / V amplifier 31B has a phase difference of 180° with respect to the signal S1O and is also a reference voltage V ref The first physical quantity component contained in the signal S1O and the second physical quantity component contained in the signal S2O are in opposite phase to each other and have substantially the same amplitude.

[0085] The physical quantity component contained in the output signal P1O of the programmable gain amplifier 32 is expressed as the signal S1 The signal S2 is an amplified signal that is the difference between the first physical quantity component included in the signal S1O and the second physical quantity component included in the signal S2O, and is in opposite phase to the signal S1O, and is connected to a reference voltage V refIt is a signal of a constant frequency f centered at . Although not shown, the physical quantity component included in the output signal P2O of the programmable gain amplifier 32 is in opposite phase to and has the same amplitude as the physical quantity component included in the signal P1O.

[0086] The physical quantity component included in the output signal SZ1O of the synchronous detection circuit 35A is a component of the signal P1O that is converted into a reference voltage V by the detection signal SDET. ref Although not shown, the physical quantity component included in the output signal SZ2O of the synchronous detection circuit 35B is a signal that has been full-wave rectified with the reference voltage V ref is a signal that has been full-wave rectified based on the reference, and has the opposite polarity to the physical quantity component contained in the signal SZ1O.

[0087] The physical quantity component included in the physical quantity detection signal SA1O is a signal with a voltage value V1 corresponding to the physical quantity detected by the physical quantity detection element 100. Although not shown in the figure, the physical quantity component included in the physical quantity detection signal SA2O is a signal with a voltage value −V1 corresponding to the physical quantity detected by the physical quantity detection element 100.

[0088] The physical quantity component included in the output signal FDO of the adder circuit 33 is a signal obtained by adding and amplifying the first physical quantity component included in the output signal S1O of the Q / V amplifier 31A and the second physical quantity component included in the output signal S2O of the Q / V amplifier 31B and removing most of the physical quantity component, and the voltage value is equal to or less than the reference voltage V ref This is the signal.

[0089] The physical quantity component included in the output signal QZO of the synchronous detection circuit 35B is calculated by subtracting the physical quantity component included in the output signal FDO of the adder circuit 33 from the reference voltage V ref is a signal that has been full-wave rectified based on the reference voltage V ref Therefore, the physical quantity component included in the static leakage detection signal QAO, which is the output signal of the smoothing circuit 36B, also has a voltage value equal to or greater than the reference voltage V ref This is the signal.

[0090] The physical quantity component included in the output signal VZO of the synchronous detection circuit 35C is calculated by subtracting the physical quantity component included in the output signal FDO of the adder circuit 33 from the reference voltage V ref is a signal that has been full-wave rectified based on the reference voltage V ref Therefore, the physical quantity component included in the vibration leakage detection signal VAO, which is the output signal of the smoothing circuit 36C, also has a voltage value equal to or greater than the reference voltage V ref This is the signal.

[0091] Fig. 6 is a diagram showing an example of waveforms of various signals corresponding to electrostatic leakage components contained in AC charges output from the physical quantity detection element 100. In Fig. 6, for the waveforms of each signal, the horizontal axis represents time and the vertical axis represents voltage. In Fig. 6, the waveforms of the signals IVO, DRV, SDET, VDET, and QDET are the same as those in Fig. 5.

[0092] The first electrostatic leakage component included in the output signal S1O of the Q / V amplifier 31A is a reference voltage V ref The first electrostatic leakage component is a signal of a constant frequency 2f centered at . The first electrostatic leakage component is a second frequency component of frequency 2f superimposed on the high-level voltage of the drive signal DRV, which is propagated to the detection electrode 114 via the first electrostatic coupling capacitance C1 between the drive electrode 113 and the detection electrode 114. Therefore, the first electrostatic leakage component contained in the signal S1O is in phase with the second frequency component of frequency 2f contained in the drive signal DRV.

[0093] The second electrostatic leakage component included in the output signal S2O of the Q / V amplifier 31B is a reference voltage V ref The second electrostatic leakage component is a signal of a constant frequency 2f centered on the driving electrode 113. The second frequency component of the frequency 2f superimposed on the high level voltage of the driving signal DRV is detected as a second electrostatic leakage component. The first electrostatic leakage component contained in the signal S1O is propagated to the detection electrode 115 via the second electrostatic coupling capacitance C2 between the electrodes 115. Therefore, the first electrostatic leakage component contained in the signal S2O is in phase with the second frequency component of frequency 2f contained in the drive signal DRV. The first electrostatic leakage component contained in the signal S1O and the second electrostatic leakage component contained in the signal S2O are in phase with each other and have substantially the same amplitude.

[0094] The electrostatic leakage component contained in the output signal P1O of the programmable gain amplifier 32 is a signal in which the difference between the first electrostatic leakage component contained in the signal S1O and the second electrostatic leakage component contained in the signal S2O is amplified and almost completely removed, and the voltage value is equal to or less than the reference voltage V ref Although not shown in the figure, the static leakage component included in the output signal P2O of the programmable gain amplifier 32 also has a voltage value equal to or greater than the reference voltage V ref This is the signal.

[0095] The electrostatic leakage component contained in the output signal SZ1O of the synchronous detection circuit 35A is detected by the detection signal SDET when the electrostatic leakage component contained in the signal P1O is converted into a reference voltage V ref is a signal that has been full-wave rectified based on the reference voltage V ref Although not shown in the figure, the electrostatic leakage component included in the output signal SZ2O of the synchronous detection circuit 35B also has a voltage value equal to or greater than the reference voltage V ref This is the signal.

[0096] The electrostatic leakage component contained in the physical quantity detection signal SA1O has a voltage value greater than or equal to the reference voltage V ref Although not shown in the figure, the static leakage component included in the physical quantity detection signal SA2O also has a voltage value equal to or greater than the reference voltage V ref This is the signal.

[0097] The electrostatic leakage component included in the output signal FDO of the adder circuit 33 is a signal obtained by adding and amplifying the first electrostatic leakage component included in the output signal S1O of the Q / V amplifier 31A and the second electrostatic leakage component included in the output signal S2O of the Q / V amplifier 31B. Therefore, the electrostatic leakage component included in the signal FDO is in phase with the second frequency component of frequency 2f included in the drive signal DRV, and is also in phase with the reference voltage V ref It is a signal with a constant frequency 2f centered at .

[0098] The electrostatic leakage component contained in the output signal QZO of the synchronous detection circuit 35B is detected by the detection signal QDET, which is a component of the output signal FDO of the adder circuit 33, and is then fed to the reference voltage V refTherefore, the electrostatic leakage component included in the electrostatic leakage detection signal QAO, which is the output signal of the smoothing circuit 36B, is a signal with a voltage value V2 corresponding to the electrostatic leakage occurring in the physical quantity detection element 100.

[0099] The electrostatic leakage component contained in the output signal VZO of the synchronous detection circuit 35C is detected by the detection signal VDET, and the electrostatic leakage component contained in the output signal FDO of the adder circuit 33 is detected by the reference voltage V ref Therefore, the electrostatic leakage component included in the vibration leakage detection signal VAO, which is the output signal of the smoothing circuit 36C, is a signal with a voltage value V3 corresponding to the electrostatic leakage generated in the physical quantity detection element 100.

[0100] Fig. 7 is a diagram showing an example of waveforms of various signals corresponding to vibration leakage components contained in AC charges output from the physical quantity detection element 100 when the physical quantity detection element 100 fails. In Fig. 7, the horizontal axis of each signal waveform represents time and the vertical axis represents voltage. In Fig. 7, the waveforms of the signals IVO, DRV, SDET, VDET, and QDET are the same as those in Figs. 5 and 6.

[0101] The first vibration leakage component included in the output signal S1O of the Q / V amplifier 31A has a phase leading 90° with respect to the signal IVO and is equal to or lower than the reference voltage V ref It is a signal of constant frequency f centered on .

[0102] The second vibration leakage component included in the output signal S2O of the Q / V amplifier 31A has a phase leading 90° with respect to the signal IVO and is equal to or lower than the reference voltage V ref It is a signal of constant frequency f centered on .

[0103] The first vibration leakage component contained in the signal S1O and the second vibration leakage component contained in the signal S2O are in phase with each other and have substantially the same amplitude.

[0104] The vibration leakage component contained in the output signal P1O of the programmable gain amplifier 32 is a signal in which the difference between the first vibration leakage component contained in the signal S1O and the second vibration leakage component contained in the signal S2O has been amplified and almost completely removed, and the voltage value is equal to or less than the reference voltage V ref Although not shown in the figure, the vibration leakage component included in the output signal P2O of the programmable gain amplifier 32 also has a voltage value equal to or greater than the reference voltage V ref This is the signal.

[0105] The vibration leakage component contained in the output signal SZ1O of the synchronous detection circuit 35A is detected by the detection signal SDET, and the vibration leakage component contained in the signal P1O is detected by the reference voltage V ref is a signal that has been full-wave rectified based on the reference voltage V ref Although not shown in the figure, the vibration leakage component included in the output signal SZ2O of the synchronous detection circuit 35B also has a voltage value equal to or greater than the reference voltage V ref This is the signal.

[0106] The vibration leakage component contained in the physical quantity detection signal SA1O has a voltage value greater than the reference voltage V ref Although not shown in the figure, the vibration leakage component included in the physical quantity detection signal SA2O also has a voltage value equal to or greater than the reference voltage V ref This is the signal.

[0107] The vibration leakage component contained in the output signal FDO of the adder circuit 33 is a signal obtained by adding and amplifying the first vibration leakage component contained in the output signal S1O of the Q / V amplifier 31A and the vibration leakage component contained in the output signal S2O of the Q / V amplifier 31B. Therefore, the vibration leakage component contained in the signal FDO has a phase lead of 90° with respect to the signal IVO and is equal to or greater than the reference voltage V ref It is a signal of constant frequency f centered on .

[0108] The vibration leakage component contained in the output signal QZO of the synchronous detection circuit 35B is detected by the detection signal QDET, and the vibration leakage component contained in the output signal FDO of the adder circuit 33 is detected by the reference voltage V ref is a signal that has been full-wave rectified based on the reference voltage V refTherefore, the vibration leakage component included in the static leakage detection signal QAO, which is the output signal of the smoothing circuit 36B, has a voltage value that is equal to or greater than the reference voltage V ref This is the signal.

[0109] The vibration leakage component contained in the output signal VZO of the synchronous detection circuit 35C is the vibration leakage component contained in the output signal FDO of the adder circuit 33, which is converted into the reference voltage V by the detection signal VDET. ref Therefore, the vibration leakage component contained in the vibration leakage detection signal VAO, which is the output signal of the smoothing circuit 36C, is a signal with a voltage value V4 corresponding to the vibration leakage that has occurred in the physical quantity detection element 100.

[0110] In reality, each signal has a waveform obtained by adding together the waveforms in Fig. 5, Fig. 6, and Fig. 7. Here, the physical quantity detection signals SA1O, SA2O contain almost no electrostatic leakage components or vibration leakage components, as shown in Fig. 6 and Fig. 7, and are signals with voltage levels corresponding to the physical quantity components, as shown in Fig. 5. As such, the physical quantity detection signals SA1O, SA2O contain almost no electrostatic leakage components or vibration leakage components, so that the adverse effects of the electrostatic leakage components and vibration leakage components on the detection of the physical quantities are extremely small. Therefore, the MCU 5 can measure the physical quantities applied to the physical quantity detection device 1 by reading the physical quantity detection signal SDO generated based on the physical quantity detection signals SA1O, SA2O.

[0111] 5 and 7, the electrostatic leakage detection signal QAO contains almost no physical quantity components or vibration leakage components, and as shown in FIG. 6, it becomes a signal with a voltage level corresponding to the electrostatic leakage components. Since the electrostatic leakage detection signal QAO contains almost no physical quantity components or vibration leakage components, the adverse effect of the physical quantity components and vibration leakage components on fault diagnosis based on the electrostatic leakage components is extremely small. Furthermore, if the wiring of the physical quantity detection element 100 is normal, the voltage of the electrostatic leakage detection signal QAO will be a predetermined value. Therefore, the fault diagnosis circuit 61 can diagnose that the wiring of the physical quantity detection element 100 is faulty if the magnitude of the electrostatic leakage detection signal QDO generated based on the electrostatic leakage detection signal QAO is not within a predetermined first range.

[0112] Furthermore, as shown in FIG. 5, the vibration leak detection signal VAO contains almost no physical component, but as shown in FIG. 6, it contains an electrostatic leakage component. Therefore, the vibration leak detection signal VAO is a signal with a voltage level corresponding to the vibration leak component, with the voltage value V3 corresponding to the electrostatic leakage component as a reference. As such, since the vibration leak detection signal VAO contains almost no physical component, the adverse effect of the physical component on fault diagnosis based on the vibration leak component is extremely small. Furthermore, although the vibration leak detection signal VAO contains an electrostatic leakage component, if the wiring of the physical quantity detection element 100 is normal, the magnitude of the electrostatic leakage component is constant, and if the physical quantity detection element 100 is normal, the vibration leakage component is almost zero, so the vibration leak detection signal VAO is a signal with a voltage level close to the voltage value V3. Therefore, the fault diagnosis circuit 62 can diagnose that the physical quantity detection element 100 is faulty if the magnitude of the vibration leak detection signal VDO generated based on the vibration leak detection signal VAO is not within the predetermined second range.

[0113] 4. Configuration and operation of the mask signal output circuit As described above, if the two wires connecting the detection electrodes 114, 115 of the physical quantity detection element 100 and the S1 terminal and S2 terminal of the semiconductor device 200 are normal, the fault diagnosis circuit 61 determines that the value of the electrostatic leakage detection signal QDO falls within a predetermined first range, and if there is an abnormality in at least one of the two wires, the value of the electrostatic leakage detection signal QDO falls outside the predetermined first range, and outputs a fault flag QF indicating whether or not the physical quantity detection device 1 is faulty. Furthermore, if the physical quantity detection element 100 is normal, the fault diagnosis circuit 62 determines that the value of the vibration leakage detection signal VDO falls within a predetermined second range, and if the physical quantity detection element 100 is faulty, the value of the vibration leakage detection signal VDO falls outside the predetermined second range, and outputs a fault flag VF indicating whether or not the physical quantity detection device 1 is faulty.

[0114] However, even if an abnormal signal other than the electrostatic leakage component or the vibration leakage component is temporarily input to the S1 terminal or the S2 terminal, the value of the electrostatic leakage detection signal QDO may deviate from the predetermined first range, temporarily setting the fault flag QF to a high level, or the value of the vibration leakage detection signal VDO may deviate from the predetermined second range, temporarily setting the fault flag VF to a high level. In such cases, the physical quantity detection device 1 is not malfunctioning, so it is preferable to mask and disable the fault flags QF and VF. When an abnormal signal is input to the S1 terminal or the S2 terminal, the abnormal signal propagates to the outputs of the multiple amplifiers, namely, the Q / V amplifiers 31A and 31B, the programmable gain amplifier 32, and the adder circuit 33. Therefore, in this embodiment, the mask signal output circuit 70 compares the output signals of the multiple amplifiers with each of the multiple detection levels set and outputs a mask signal MSK based on the comparison result. The disablement determination circuit 80 disables the fault flags QF and VF based on the mask signal MSK. The programmable gain amplifier 32 outputs two signals P1O and P2O of opposite phases, but these two signals have the same amplitude, so the mask signal output circuit 70 only needs to compare one of the signals P1O and P2O with the detection level.

[0115] 8 is a diagram showing an example of the configuration of the mask signal output circuit 70. As shown in Fig. 8, the mask signal output circuit 70 includes comparators 71, 72, 73, and 74, a detection level setting circuit 75, and a logic circuit 76.

[0116] The comparator 71 compares the level of the output signal S1O of the Q / V amplifier 31A with a set detection level LV1 and outputs a comparison result signal S1F indicating the comparison result. Specifically, the comparator 71 outputs a low-level comparison result signal S1F when the voltage level of the signal S1O is lower than the detection level LV1, and outputs a high-level comparison result signal S1F when the voltage level of the signal S1O is higher than the detection level LV1.

[0117] The comparator 72 compares the level of the output signal S2O of the Q / V amplifier 31B with a set detection level LV2 and outputs a comparison result signal S2F indicating the comparison result. Specifically, the comparator 72 outputs a low-level comparison result signal S2F when the voltage level of the signal S2O is lower than the detection level LV2, and outputs a high-level comparison result signal S2F when the voltage level of the signal S2O is higher than the detection level LV2.

[0118] The comparator 73 compares the level of the output signal P2O of the programmable gain amplifier 32 with a set detection level LV3 and outputs a comparison result signal P2F indicative of the comparison result. Specifically, the comparator 73 outputs a low-level comparison result signal P2F when the voltage level of the signal P2O is lower than the detection level LV3, and outputs a high-level comparison result signal P2F when the voltage level of the signal P2O is higher than the detection level LV3. Note that the comparator 73 may also compare the level of the output signal P1O of the programmable gain amplifier 32 with the detection level LV3 and output the comparison result signal P2F.

[0119] The comparator 74 compares the level of the output signal FDO of the adder circuit 33 with a set detection level LV4 and outputs a comparison result signal FDF indicative of the comparison result. Specifically, the comparator 74 outputs a low-level comparison result signal FDF when the voltage level of the signal FDO is lower than the detection level LV4, and outputs a high-level comparison result signal FDF when the voltage level of the signal FDO is higher than the detection level LV4.

[0120] Note that comparator 71 is an example of a "first comparator," comparator 72 is an example of a "second comparator," comparator 73 is an example of a "third comparator," and comparator 74 is an example of a "fourth comparator." Furthermore, detection level LV1 is an example of a "first detection level," detection level LV2 is an example of a "second detection level," detection level LV3 is an example of a "third detection level," and detection level LV4 is an example of a "fourth detection level." Furthermore, comparison result signal S1F is an example of a "first comparison result signal," comparison result signal S2F is an example of a "second comparison result signal," comparison result signal P2F is an example of a "third comparison result signal," and comparison result signal FDF is an example of a "fourth comparison result signal."

[0121] The detection level setting circuit 75 outputs detection levels LV1, LV2, LV3, and LV4. For example, the detection levels LV1, LV2, LV3, and LV4 are set to levels corresponding to thresholds for determining whether or not an expected abnormal signal has been input. The detection levels LV1, LV2, LV3, and LV4 may be fixed or variable. For example, the detection levels LV1, LV2, LV3, and LV4 may be variably set according to values ​​stored in a register in the storage unit 91 that can be rewritten from outside the semiconductor device 200.

[0122] The logic circuit 76 operates in response to the master clock signal MCLK and outputs a mask signal MSK based on the comparison result signals S1F, S2F, P2F, and FDF. The correspondence relationship between the logical levels of the comparison result signals S1F, S2F, P2F, and FDF and the logical level of the mask signal MSK is determined so that the mask signal MSK goes low when the physical quantity detection device 1 has failed, and goes high when each of the multiple types of expected abnormal signals is input.

[0123] 9 is a diagram showing an example of the correspondence between the logical levels of the comparison result signals S1F, S2F, P2F, and FDF and the logical level of the mask signal MSK. In FIG. 9, "L" represents a low level, and "H" represents a high level.

[0124] For example, when the physical quantity detection element 100 resonates due to environmental vibration, an in-phase or out-of-phase resonance signal is input to the S1 terminal and the S2 terminal as an abnormal signal. Alternatively, when an excessive angular velocity exceeding the detectable range is temporarily applied to the physical quantity detection element 100, an excessive angular velocity component with an out-of-phase is input to the S1 terminal and the S2 terminal as an abnormal signal.

[0125] When a large-amplitude, in-phase resonant signal is input, as shown in FIG. 10, the output signals S1O and S2O of the Q / V amplifiers 31A and 31B saturate and become square waves, causing at least one of the fault flags QF and VF to go high. At this time, the comparison result signals S1F, S2F, and FDF go high, and the comparison result signal P2F goes low. Therefore, when the comparison result signal S1F is high, the comparison result signal S2F is high, the comparison result signal P2F is low, and the comparison result signal FDF is high, the logic circuit 76 outputs a high-level mask signal MSK indicating that the fault flags QF and VF are invalid. Therefore, both of the fault diagnosis result signals QFX and VFX go low.

[0126] On the other hand, when a relatively small-amplitude, in-phase resonant signal is input, as shown in FIG. 11, the output signals S1O and S2O of the Q / V amplifiers 31A and 31B do not saturate, and the output signal FDO of the adder circuit 33 saturates and becomes a square wave, causing at least one of the fault flags QF and VF to go high. At this time, the comparison result signals S1F, S2F, and P2F go low, and the comparison result signal FDF goes high. Therefore, when the comparison result signal S1F is low, the comparison result signal S2F is low, the comparison result signal P2F is low, and the comparison result signal FDF is high, the logic circuit 76 outputs a high-level mask signal MSK indicating that the fault flags QF and VF are invalid. Therefore, both the fault diagnosis result signals QFX and VFX go low.

[0127] Furthermore, when an excessively large angular velocity component is input or when a large-amplitude, out-of-phase resonance signal is input, as shown in FIG. 12, the output signals S1O and S2O of the Q / V amplifiers 31A and 31B saturate and become square waves, and at least one of the fault flags QF and VF goes high. At this time, the comparison result signals S1F, S2F, and P2F go high, and the comparison result signal FDF goes low. Also, when both an in-phase resonance signal and an out-of-phase resonance signal are input, the output signals S1O and S2O of the Q / V amplifiers 31A and 31B saturate and become square waves, and at least one of the fault flags QF and VF goes high. At this time, the comparison result signals S1F, S2F, P2F, and FDF all go high. Therefore, when the comparison result signal S1F is at a high level, the comparison result signal S2F is at a high level, and the comparison result signal P2F is at a high level, the logic circuit 76 outputs a high-level mask signal MSK indicating that the fault flags QF and VF are invalidated, regardless of the logical level of the comparison result signal FDF. As a result, both of the fault diagnosis result signals QFX and VFX become low.

[0128] On the other hand, when the physical quantity detection element 100 is normal, both of the failure flags QF and VF are at low level. At this time, the comparison result signals S1F, S2F, P2F, and FDF are all at low level. Furthermore, when the failure of the physical quantity detection element 100 is minor or when one or both of the two wires connecting the detection electrodes 114 and 115 to the S1 terminal and the S2 terminal are disconnected, at least one of the failure flags QF and VF is at high level. In this case, too, the comparison result signals S1F, S2F, P2F, and FDF are all at low level. Therefore, when the comparison result signals S1F, S2F, P2F, and FDF are all at low level, the logic circuit 76 outputs a low-level mask signal MSK indicating that the failure flags QF and VF are not invalidated. Therefore, the failure diagnosis result signals QFX and VFX are at high level, respectively, indicating that the failure flags QF and VF are not invalidated. ,VF has the same logic level.

[0129] Furthermore, if the failure of the physical quantity detection element 100 is severe, large leakage vibration occurs, causing the output signal S1O of the Q / V amplifier 31A to saturate and become a square wave, and at least one of the failure flags QF and VF to go high. At this time, the comparison result signals S1F, P2F, and FDF go high, and the comparison result signal S2F goes low. Therefore, when the comparison result signals S1F, P2F, and FDF are high and the comparison result signal S2F is low, the logic circuit 76 outputs a low-level mask signal MSK indicating that the failure flags QF and VF are not invalidated. Therefore, the failure diagnosis result signals QFX and VFX go to the same logical level as the failure flags QF and VF, respectively.

[0130] To prevent the fault diagnosis result signals QFX and VFX from erroneously going high when an abnormal signal such as a resonance signal is input, the period during which the fault flags QF and VF are high must be included in the period during which the mask signal MSK is high. For example, when an impact is applied to the physical quantity detection element 100 and in-phase resonance is excited, the amplitude of the output signal FDO of the adder circuit 33 gradually increases, as shown in FIG. 13. The comparison result signal FDF goes low when the voltage level of the signal FDO is lower than the detection level LV4, and goes high when the voltage level of the signal FDO is higher than the detection level LV4. That is, after changing from low to high, the comparison result signal FDF periodically alternates between high and low levels until the resonance decreases.

[0131] When the comparison result signal FDF changes from low to high while the mask signal MSK is at low level, the logic circuit 76 changes the mask signal MSK from low to high. After changing the mask signal MSK to high, the logic circuit 76 changes the mask signal MSK from high to low when the comparison result signal FDF remains at low for a period of time tx after changing from high to low. For example, the logic circuit 76 changes the mask signal MSK from high to low when the comparison result signal FDF remains at low for a period of time tx from when the comparison result signal FDF changes from high to low until the number of pulses of the master clock signal MCLK corresponding to the period tx is counted. The period tx is set to a time longer than the resonance period of the physical quantity detection element 100.

[0132] On the other hand, when the amplitude of the signal FDO gradually increases and exceeds the detection level LV4, reaching the vicinity of the voltage level LVF, the fault flag QF changes from low to high. Also, when the amplitude of the signal FDO gradually decreases and falls below the voltage level LVF, the fault flag QF changes from high to low. Conversely, the detection level LV4 is set to a voltage lower than the voltage level LVF at which the physical quantity detection device 1 is determined to be faulty in the signal FDO. By setting the detection level LV4 to a voltage lower than the voltage level LVF, the rising edge of the mask signal MSK at time t1 is earlier than the rising edge of the fault flag QF at time t2, and the falling edge of the mask signal MSK at time t4 is later than the falling edge of the fault flag QF at time t3. Therefore, the period during which the fault flag QF is at high level is included in the period during which the mask signal MSK is at high level, and the fault diagnosis result signal QFX is prevented from erroneously setting to high level. The detection levels LV1, LV2, and LV3 are also set to voltage levels such that the rising edge of the mask signal MSK is earlier than the rising edge of the fault flag QF and the falling edge of the mask signal MSK is later than the falling edge of the fault flag QF. As with the fault flag QF, the detection levels LV1, LV2, LV3, and LV4 are also set such that the rising edge of the mask signal MSK is earlier than the rising edge of the fault flag VF and the falling edge of the mask signal MSK is later than the falling edge of the fault flag VF.

[0133] 5. Effects In the physical quantity detection device 1 of this embodiment, if a fault such as a break occurs in the wiring connecting the physical quantity detection element 100 and the physical quantity detection circuit 210, the magnitudes of the first electrostatic leakage component and the second electrostatic leakage component, which are the second frequency component included in the drive signal DRV propagated to the detection electrodes 114, 115, respectively, change. Therefore, the electrostatic leakage detection signal QAO generated by the fault diagnosis signal output circuit 38 based on the first electrostatic leakage component and the second electrostatic leakage component also changes, and the fault diagnosis circuit 61 can diagnose a fault in the wiring based on the electrostatic leakage detection signal QDO converted from the electrostatic leakage detection signal QAO.

[0134] Furthermore, in the physical quantity detection device 1 of this embodiment, if a failure such as breakage occurs in the physical quantity detection element 100, the magnitudes of the first vibration leakage component and the second vibration leakage component generated in the detection electrodes 114, 115, respectively, change based on the vibration of the physical quantity detection element 100. As a result, the vibration leakage detection signal VAO generated by the fault diagnosis signal output circuit 38 based on the first vibration leakage component and the second vibration leakage component also changes, and the fault diagnosis circuit 62 can diagnose a failure in the physical quantity detection element 100 based on the vibration leakage detection signal VDO converted from the vibration leakage detection signal VAO.

[0135] Furthermore, in the physical quantity detection device 1 of this embodiment, the physical quantity component included in the first signal output from the detection electrode 114 and the physical quantity component included in the second signal output from the detection electrode 115 are in opposite phases, so in the physical quantity detection circuit 210, the physical quantity component is amplified by the programmable gain amplifier 32 and attenuated by the adder circuit 33. Therefore, the physical quantity detection circuit 210 can generate the physical quantity detection signal SDO with high accuracy, and reduces the risk that the accuracy of the electrostatic leakage detection signal QDO and the vibration leakage detection signal VDO will be reduced due to the physical quantity component.

[0136] Furthermore, in the physical quantity detection device 1 of this embodiment, the first electrostatic leakage component contained in the first signal and the second electrostatic leakage component contained in the second signal are in phase, and the first vibration leakage component contained in the first signal and the second vibration leakage component contained in the second signal are in phase, so in the physical quantity detection circuit 210, the electrostatic leakage component and the vibration leakage component are amplified by the adder circuit 33 and attenuated by the programmable gain amplifier 32. Therefore, the physical quantity detection circuit 210 can generate the electrostatic leakage detection signal QDO and the vibration leakage detection signal VDO with high accuracy, and reduces the risk that the electrostatic leakage component and the vibration leakage component will reduce the accuracy of the physical quantity detection signal SDO.

[0137] Furthermore, in the physical quantity detection device 1 of this embodiment, the fault diagnosis circuit 61 can perform fault diagnosis of the wiring connecting the physical quantity detection element 100 and the physical quantity detection circuit 210 based on the electrostatic leakage component, so it is possible to use the physical quantity detection element 100 that is tuned so that the vibration leakage component is zero or close to zero. Therefore, the physical quantity detection device 1 of this embodiment can reduce the risk that the vibration leakage component will reduce the detection accuracy of the physical quantity.

[0138] Furthermore, in the physical quantity detection device 1 of this embodiment, if the physical quantity detection element 100 temporarily goes into an abnormal state due to mechanical shock or vibration, etc., and an abnormality signal is input to the physical quantity detection circuit 210, there is a possibility that failure flags QF, VF indicating a failure of the physical quantity detection device 1 will be output. In this case, the failure flags QF, VF are invalidated based on the mask signal MSK. In particular, by making the rising edge of the mask signal MSK earlier than the rising edge of the failure flags QF, VF and making the falling edge of the mask signal MSK later than the falling edge of the failure flags QF, VF, the entire period in which the high-level failure flags QF, VF are output is included in the period in which the high-level mask signal MSK is output, and therefore the failure flags QF, VF can be reliably invalidated. Therefore, according to the physical quantity detection device 1 of this embodiment, When an abnormal signal generated by resonance or the like of the detection element 100 is input to the physical quantity detection circuit 210, the risk of erroneously diagnosing that the physical quantity detection device 1 is at fault can be reduced.

[0139] 6. Variations The present invention is not limited to the present embodiment, and various modifications are possible within the scope of the present invention.

[0140] For example, in the above embodiment, the mask signal output circuit 70 compares the voltage levels of the signals S1O, S2O, P2O, and FDO with the positive detection levels LV1, LV2, LV3, and LV4, respectively, and outputs the comparison result signals S1F, S2F, P2F, and FDF. Alternatively, the mask signal output circuit 70 may compare the voltage levels of the signals S1O, S2O, P2O, and FDO with the positive detection levels LV1, LV2, LV3, and LV4 and the negative detection levels LV1', LV2', LV3', and LV4', respectively, and output the comparison result signals S1F, S2F, P2F, and FDF.

[0141] Furthermore, in the above embodiment, the physical quantity detection device 1 generates fault diagnosis result signals QFX, VFX based on the fault flags QF, VF and outputs the fault diagnosis result signals QFX, VFX to the outside via the interface circuit 90, but it may also generate one fault diagnosis result signal QVFX based on a fault flag QVF, which is the logical sum of the fault flags QF and VF, and output the fault diagnosis result signal QVFX to the outside via the interface circuit 90.

[0142] In the above embodiment, the physical quantity detection device 1 includes the physical quantity detection element 100 that detects angular velocity as a physical quantity, but may include a physical quantity detection element that detects a physical quantity other than angular velocity. For example, the physical quantity detection device 1 may include a physical quantity detection element that detects a physical quantity such as acceleration, angular acceleration, velocity, or force.

[0143] Furthermore, in the above embodiment, the physical quantity detection device 1 includes one physical quantity detection element, but may include multiple physical quantity detection elements. For example, the physical quantity detection device 1 may include multiple physical quantity detection elements, each of which may detect a physical quantity using one of two or more mutually orthogonal axes as a detection axis. Furthermore, for example, the physical quantity detection device 1 may include multiple physical quantity detection elements, each of which may detect one of multiple types of physical quantities, such as angular velocity, acceleration, angular acceleration, velocity, and force. In other words, the physical quantity detection device 1 may be a composite sensor.

[0144] In the above embodiment, the vibrating element of the physical quantity detection element 100 is a double-T quartz crystal vibrating element. However, the vibrating element of the physical quantity detection element that detects various physical quantities may be, for example, a tuning fork or comb type, or may be a tuning element type having a triangular prism, a square prism, a cylindrical shape, or the like. Instead of quartz crystal (SiO2), the material of the vibrating element of the physical quantity detection element may be, for example, a piezoelectric material such as a piezoelectric single crystal such as lithium tantalate (LiTaO3) or lithium niobate (LiNbO3), or a piezoelectric ceramic such as lead zirconate titanate (PZT), or a silicon semiconductor. The vibrating element of the physical quantity detection element may have a structure in which a piezoelectric thin film such as zinc oxide (ZnO) or aluminum nitride (AlN) is sandwiched between drive electrodes and disposed on a portion of the surface of a silicon semiconductor. For example, the physical quantity detection element may be a MEMS element. MEMS stands for Micro Electro Mechanical Systems.

[0145] Furthermore, in the above embodiment, a piezoelectric type physical quantity detection element is exemplified, but the physical quantity detection element for detecting various physical quantities is not limited to a piezoelectric type element, and may be a capacitance type, an electrodynamic type, an eddy current type, an optical type, or the like. The detection method of the physical quantity detection element is not limited to the vibration type, but may be, for example, an optical type, a rotation type, or a fluid type.

[0146] The above-described embodiment and modifications are merely examples, and the present invention is not limited to these. For example, the embodiments and modifications can be combined as appropriate.

[0147] The present invention includes configurations that are substantially the same as the configurations described in the embodiments, for example, configurations with the same functions, methods, and results, or configurations with the same purpose and effects. The present invention also includes configurations that replace non-essential parts of the configurations described in the embodiments. The present invention also includes configurations that achieve the same effects or purposes as the configurations described in the embodiments. The present invention also includes configurations that add publicly known technology to the configurations described in the embodiments.

[0148] The following can be derived from the above-described embodiment and modifications.

[0149] One aspect of the physical quantity detection circuit is a physical quantity detection signal output circuit including an amplifier circuit that amplifies a signal output from a physical quantity detection element that detects a physical quantity, and outputs a physical quantity detection signal corresponding to the physical quantity; a fault diagnosis signal output circuit that outputs a fault diagnosis signal based on output signals of at least some of the amplifiers included in the amplifier circuit; a fault diagnosis circuit that performs a fault diagnosis based on the fault diagnosis signal and outputs a fault flag indicating the diagnosis result; a mask signal output circuit that compares the level of the signal output from each of the plurality of amplifiers with each of a plurality of set detection levels and outputs a mask signal based on the comparison result; an invalidation determination circuit that invalidates the failure flag based on the mask signal; Equipped with.

[0150] In this physical quantity detection circuit, if a fault, such as a break, occurs in the wiring connected to the physical quantity detection element, the output signals of the multiple amplifiers change, causing a change in the fault diagnosis signal. Therefore, the fault diagnosis circuit can perform a fault diagnosis based on the fault diagnosis signal and output a fault flag indicating the diagnosis result. Meanwhile, if the physical quantity detection element temporarily goes into an abnormal state due to mechanical shock or vibration, for example, and an abnormality signal is input, the output signals of the multiple amplifiers may change, potentially causing a fault flag to be output indicating a fault. In this case, the fault flag is disabled based on the mask signal. Therefore, this physical quantity detection circuit can reduce the risk of erroneously diagnosing a fault when an abnormality signal caused by, for example, resonance of the physical quantity detection element is input.

[0151] In one aspect of the physical quantity detection circuit, The plurality of amplifiers a first amplifier that amplifies a first signal output from a first detection electrode of the physical quantity detection element; a second amplifier that amplifies a second signal output from a second detection electrode of the physical quantity detection element; a third amplifier that amplifies the difference between the signal output from the first amplifier and the signal output from the second amplifier; may include:

[0152] In one aspect of the physical quantity detection circuit, The fault diagnosis signal output circuit comprises: an adder circuit that outputs a signal obtained by adding the signal output from the first amplifier and the signal output from the second amplifier; a synchronous detection circuit that synchronously detects the signal output from the adder circuit; and outputs the fault diagnosis signal based on a signal output from the synchronous detection circuit.

[0153] In one aspect of the physical quantity detection circuit, The mask signal output circuit a first comparator that compares the level of the signal output from the first amplifier with a set first detection level and outputs a first comparison result signal that indicates the comparison result; a second comparator that compares the level of the signal output from the second amplifier with a set second detection level and outputs a second comparison result signal that indicates the comparison result; a third comparator that compares the level of the signal output from the third amplifier with a set third detection level and outputs a third comparison result signal that indicates the comparison result; a fourth comparator that compares the level of the signal output from the adding circuit with a set fourth detection level and outputs a fourth comparison result signal that indicates the comparison result; a logic circuit that outputs the mask signal based on the first comparison result signal, the second comparison result signal, the third comparison result signal, and the fourth comparison result signal; may include:

[0154] In one aspect of the physical quantity detection circuit, The mask signal may rise earlier than the fault flag, and the mask signal may fall later than the fault flag.

[0155] According to this physical quantity detection circuit, when an abnormality signal is input, the entire period during which a fault flag indicating a fault is output is included in the period during which a mask signal indicating that the fault flag is to be disabled is output, so the fault flag can be reliably disabled.

[0156] In one aspect of the physical quantity detection circuit, The mask signal output circuit When the first comparison result signal is at a high level, the second comparison result signal is at a high level, the third comparison result signal is at a low level, and the fourth comparison result signal is at a high level, or When the first comparison result signal is at a low level, the second comparison result signal is at a low level, the third comparison result signal is at a low level, and the fourth comparison result signal is at a high level, or When the first comparison result signal is at a high level, the second comparison result signal is at a high level, and the third comparison result signal is at a high level, The mask signal may be output to indicate that the failure flag is to be invalidated.

[0157] According to this physical quantity detection circuit, when the physical quantity detection element temporarily resonates due to mechanical shock or vibration, and an in-phase or differential resonant signal is input, the fault flag can be invalidated, thereby reducing the risk of misdiagnosing a fault.

[0158] In one aspect of the physical quantity detection circuit, the first signal includes a first physical quantity component and a first electrostatic leakage component propagated to the first detection electrode via a first electrostatic coupling capacitance between a drive electrode of the physical quantity detection element and the first detection electrode; the second signal includes a second physical quantity component having an opposite phase to the first physical quantity component, and a second electrostatic leakage component having the same phase as the first electrostatic leakage component and propagating to the second detection electrode via a second electrostatic coupling capacitance between the drive electrode and the second detection electrode of the physical quantity detection element; The physical quantity detection signal output circuit A signal output from the third amplifier is synchronously detected based on the first detection signal. outputting the physical quantity detection signal based on the signal obtained by the above measurement; The fault diagnosis signal output circuit comprises: synchronously detecting a signal obtained by adding the signal output from the first amplifier and the signal output from the second amplifier based on a second detection signal, and outputting the fault diagnosis signal based on the signal obtained by the synchronous detection; The frequency of the second detected signal may be twice the frequency of the first detected signal.

[0159] In this physical quantity detection circuit, the first physical quantity component included in the first signal and the second physical quantity component included in the second signal are out of phase with each other, so the physical quantity components are amplified by the third amplifier and attenuated by the adder circuit. Therefore, this physical quantity detection circuit can generate a physical quantity detection signal with high accuracy and reduce the risk that the physical quantity components will reduce the accuracy of the fault diagnosis signal.

[0160] In addition, in this physical quantity detection circuit, the first electrostatic leakage component contained in the first signal and the second electrostatic leakage component contained in the second signal are in phase, so the electrostatic leakage component is amplified by the adder circuit and attenuated by the third amplifier. Therefore, this physical quantity detection circuit can generate a fault diagnosis signal with high accuracy and reduces the risk of the electrostatic leakage component reducing the accuracy of the physical quantity detection signal.

[0161] In one aspect of the physical quantity detection circuit, the first signal includes a first physical quantity component, and when the physical quantity detection element fails, further includes a first vibration leakage component based on vibration of the physical quantity detection element; the second signal includes a second physical quantity component in opposite phase to the first physical quantity component, and when the physical quantity detection element fails, further includes a second vibration leakage component in phase with the first vibration leakage component based on the vibration of the physical quantity detection element; The physical quantity detection signal output circuit synchronously detecting the signal output from the third amplifier based on the first detection signal, and outputting the physical quantity detection signal based on the signal obtained by the synchronous detection; The fault diagnosis signal output circuit comprises: synchronously detecting a signal obtained by adding the signal output from the first amplifier and the signal output from the second amplifier based on a third detection signal, and outputting the fault diagnosis signal based on the signal obtained by the synchronous detection; The third detected signal may be shifted in phase by 90° from the first detected signal.

[0162] In this physical quantity detection circuit, the first physical quantity component included in the first signal and the second physical quantity component included in the second signal are out of phase with each other, so the physical quantity components are amplified by the third amplifier and attenuated by the adder circuit. Therefore, this physical quantity detection circuit can generate a physical quantity detection signal with high accuracy and reduce the risk that the physical quantity components will reduce the accuracy of the fault diagnosis signal.

[0163] Furthermore, in this physical quantity detection circuit, the first vibration leakage component contained in the first signal and the second vibration leakage component contained in the second signal are in phase, so the vibration leakage component is amplified by the adder circuit and attenuated by the third amplifier. Therefore, this physical quantity detection circuit can generate a fault diagnosis signal with high accuracy, and reduces the risk of the vibration leakage component reducing the accuracy of the physical quantity detection signal.

[0164] One aspect of the physical quantity detection device is a semiconductor device including one aspect of the physical quantity detection circuit; the physical quantity detection element; a package that accommodates the physical quantity detection element and the semiconductor device; Equipped with.

[0165] In this physical quantity detection device, if a fault such as a break occurs in the wiring connecting the physical quantity detection element and the physical quantity detection circuit, the fault diagnosis signal changes, and the fault diagnosis circuit can perform fault diagnosis based on the fault diagnosis signal and output a fault flag indicating the diagnosis result. On the other hand, if the physical quantity detection element temporarily goes into an abnormal state due to mechanical shock or vibration, for example, and an abnormality signal is input to the physical quantity detection circuit, a fault flag indicating a fault may be output, but in this case the fault flag is disabled based on the mask signal. Therefore, this physical quantity detection device can reduce the risk of erroneously diagnosing a fault when an abnormality signal caused by, for example, resonance of the physical quantity detection element is input.

[0166] In one aspect of the physical quantity detection device, The physical quantity detection element may be a double-T type gyro sensor element. [Explanation of symbols]

[0167] 1...physical quantity detection device, 5...MCU, 10...reference voltage circuit, 20...drive circuit, 21...current-voltage conversion circuit, 22...full-wave rectification circuit, 23...auto gain control circuit, 24...drive signal generation circuit, 25...phase shift circuit, 26a...buffer circuit, 26b...buffer circuit, 27...FLL circuit, 28...phase adjustment circuit, 29...frequency divider circuit, 30...detection circuit, 31A...Q / V amplifier, 31B...Q / V amplifier, 32...programmable gain amplifier, 33...adder circuit, 34...amplifier circuit, 35A...synchronous detection circuit, 35B...synchronous detection circuit, 35C...synchronous detection circuit, 36A...smoothing circuit, 36B...smoothing circuit, 36C...smoothing circuit, 37...physical quantity detection signal output circuit, 38...fault diagnosis signal output circuit, 40...selector, 41...analog / digital conversion circuit, 42...analog Log / digital conversion circuit, 50...oscillator circuit, 51...digital signal processing circuit, 60...control circuit, 61...fault diagnosis circuit, 62...fault diagnosis circuit, 70...mask signal output circuit, 71, 2, 73, 74...comparator, 75...detection level setting circuit, 76...logic circuit, 80...invalidation determination circuit, 81...AND circuit, 82...AND circuit, 83...NOT circuit, 90...interface circuit, 91...storage unit, 100...physical quantity detection element, 101a, 101b...drive vibration arm, 102...detection vibration arm, 103...weight portion, 104a, 104b...drive base, 105a, 105b...connecting arm, 106...weight portion, 107...detection base, 112, 113...drive electrode, 114, 115...detection electrode, 116...common electrode, 200...semiconductor device, 210...physical quantity detection circuit, 300...package

Claims

1. a physical quantity detection signal output circuit including an amplifier circuit that amplifies a signal output from a physical quantity detection element that detects a physical quantity, and outputs a physical quantity detection signal corresponding to the physical quantity; a fault diagnosis signal output circuit that outputs a fault diagnosis signal based on output signals of at least some of the amplifiers included in the amplifier circuit; a fault diagnosis circuit that performs a fault diagnosis based on the fault diagnosis signal and outputs a fault flag indicating the diagnosis result; a mask signal output circuit that compares the level of the signal output from each of the plurality of amplifiers with each of a plurality of set detection levels and outputs a mask signal based on the comparison result; an invalidation determination circuit that invalidates the failure flag based on the mask signal; A physical quantity detection circuit comprising:

2. In claim 1, The plurality of amplifiers a first amplifier that amplifies a first signal output from a first detection electrode of the physical quantity detection element; a second amplifier that amplifies a second signal output from a second detection electrode of the physical quantity detection element; a third amplifier that amplifies a difference between a signal output from the first amplifier and a signal output from the second amplifier; A physical quantity detection circuit comprising:

3. In claim 2, The fault diagnosis signal output circuit comprises: an adder circuit that outputs a signal obtained by adding the signal output from the first amplifier and the signal output from the second amplifier; a synchronous detection circuit that synchronously detects the signal output from the adder circuit; and outputs the fault diagnosis signal based on the signal output from the synchronous detection circuit.

4. In claim 3, The mask signal output circuit a first comparator that compares the level of the signal output from the first amplifier with a set first detection level and outputs a first comparison result signal that indicates the comparison result; a second comparator that compares the level of the signal output from the second amplifier with a set second detection level and outputs a second comparison result signal that indicates the comparison result; a third comparator that compares the level of the signal output from the third amplifier with a set third detection level and outputs a third comparison result signal indicative of the comparison result; a fourth comparator that compares the level of the signal output from the adding circuit with a set fourth detection level and outputs a fourth comparison result signal indicative of the comparison result; a logic circuit that outputs the mask signal based on the first comparison result signal, the second comparison result signal, the third comparison result signal, and the fourth comparison result signal; A physical quantity detection circuit comprising:

5. In claim 1, The physical quantity detection circuit, wherein the rising edge of the mask signal is earlier than the rising edge of the fault flag, and the falling edge of the mask signal is later than the falling edge of the fault flag.

6. In claim 4, The mask signal output circuit The first comparison result signal is at a high level, and the second comparison result signal is at a high level. , when the third comparison result signal is at a low level and the fourth comparison result signal is at a high level, or the first comparison result signal is at a low level, the second comparison result signal is at a low level, the third comparison result signal is at a low level, and the fourth comparison result signal is at a high level; or When the first comparison result signal is at a high level, the second comparison result signal is at a high level, and the third comparison result signal is at a high level, a physical quantity detection circuit that outputs the mask signal indicating that the failure flag is to be invalidated;

7. In claim 2, the first signal includes a first physical quantity component and a first electrostatic leakage component propagated to the first detection electrode via a first electrostatic coupling capacitance between a drive electrode of the physical quantity detection element and the first detection electrode, the second signal includes a second physical quantity component having an opposite phase to the first physical quantity component, and a second electrostatic leakage component having the same phase as the first electrostatic leakage component and propagating to the second detection electrode via a second electrostatic coupling capacitance between the drive electrode and the second detection electrode of the physical quantity detection element; The physical quantity detection signal output circuit synchronously detecting the signal output from the third amplifier based on the first detection signal, and outputting the physical quantity detection signal based on the signal obtained by the synchronous detection; The fault diagnosis signal output circuit comprises: synchronously detecting a signal obtained by adding the signal output from the first amplifier and the signal output from the second amplifier based on a second detection signal, and outputting the fault diagnosis signal based on the signal obtained by the synchronous detection; A physical quantity detection circuit, wherein the frequency of the second detection signal is twice the frequency of the first detection signal.

8. In claim 2, the first signal includes a first physical quantity component, and when the physical quantity detection element fails, further includes a first vibration leakage component based on vibration of the physical quantity detection element; the second signal includes a second physical quantity component in opposite phase to the first physical quantity component, and when the physical quantity detection element fails, further includes a second vibration leakage component in phase with the first vibration leakage component based on the vibration of the physical quantity detection element, The physical quantity detection signal output circuit synchronously detecting the signal output from the third amplifier based on the first detection signal, and outputting the physical quantity detection signal based on the signal obtained by the synchronous detection; The fault diagnosis signal output circuit comprises: synchronously detecting a signal obtained by adding the signal output from the first amplifier and the signal output from the second amplifier based on a third detection signal, and outputting the fault diagnosis signal based on the signal obtained by the synchronous detection; a phase of the third detection signal being shifted by 90° from a phase of the first detection signal;

9. a semiconductor device including the physical quantity detection circuit according to claim 1; the physical quantity detection element; a package that accommodates the physical quantity detection element and the semiconductor device; A physical quantity detection device comprising:

10. In claim 9, The physical quantity detection device, wherein the physical quantity detection element is a double T-type gyro sensor element.

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