JP6756175B2 - Rectifier circuit, drive circuit, physical quantity detector, electronic device and moving object - Google Patents

Description

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

Currently, in various systems and electronic devices, physical quantity detection devices capable of detecting various physical quantities, such as an acceleration sensor for detecting acceleration and a gyro sensor for detecting angular velocity, are widely used.

For example, Patent Document 1 describes a current amplifier that amplifies an output signal from a piezoelectric element and a full wave that inputs the output signal of the current amplifier to a bandpass filter and rectifies the output signal from the bandpass filter to obtain a DC voltage. A rectifier circuit, an automatic gain control circuit whose amplification degree with respect to the output signal from the bandpass filter changes according to the value of the output signal from the full-wave rectifier circuit, and a voltage settled according to the value of the output signal from the automatic gain control circuit. A driver for driving an element and an angular velocity sensor having a drive circuit are disclosed.

Japanese Unexamined Patent Publication No. 2000-002542

However, like the angular velocity sensor described in Patent Document 1, the conventional physical quantity detection device requires a full-wave rectification operation in the drive circuit, so that the current consumption increases and it is difficult to meet the demand for low power consumption. In some cases.

The present invention has been made in view of the above problems, and according to some aspects of the present invention, it is possible to provide a rectifier circuit and a drive circuit capable of selecting low power consumption operation. According to some aspects of the present invention, it is possible to provide a physical quantity detecting device using the drive circuit. Further, according to some aspects of the present invention, it is possible to provide an electronic device and a moving body using the physical quantity detecting device.

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

[Application example 1]
The rectifier circuit according to this application example controls whether to function as a full-wave rectifier circuit that outputs the input signal by full-wave rectification or as a half-wave rectifier circuit that outputs the input signal by half-wave rectification. Can be switched by.

According to the rectifier circuit according to this application example, when the control signal is set to function as a full-wave rectifier circuit, the voltage accuracy of the output signal is improved and the control signal is set to function as a half-wave rectifier circuit. When set, the power consumption is reduced because the inverting amplification operation of the input signal required for full-wave rectification is not required. As described above, according to the rectifier circuit according to the present application example, high-precision operation or low power consumption operation can be selected.

[Application example 2]
The rectifying circuit according to the above application example includes a comparator that compares the input signal with the threshold voltage, an inverting amplification circuit into which the input signal is input, an output signal of the inverting amplification circuit, and a second inverting amplification circuit based on the control signal. Select either one of the input signal and the output signal of the first selection circuit based on the output signal of the comparator and the first selection circuit that selects and outputs one of the reference voltages of 1. The second selection circuit to be output may be included.

The rectifier circuit according to this application example functions as a full-wave rectifier circuit by setting a control signal so that the first selection circuit selects and outputs the output signal of the inverting amplification circuit, and the first selection circuit. Functions as a half-wave rectifier circuit by setting a control signal so that the first reference voltage is selected and output. According to the rectifier circuit according to this application example, the inverting amplifier circuit operates when it functions as a full-wave rectifier circuit to improve the voltage accuracy of the output signal, and when it functions as a half-wave rectifier circuit, it is inverted. Power consumption is reduced because it is not necessary to operate the amplifier circuit. As described above, according to the rectifier circuit according to the present application example, high-precision operation or low power consumption operation can be selected.

[Application example 3]
The drive circuit according to this application example includes one of the above rectifier circuits and a comparison determination circuit for determining whether the voltage obtained by integrating the output signals of the rectifier circuit is higher or lower than the second reference voltage. , A drive signal generation circuit that generates a drive signal whose amplitude is adjusted based on the determination result of the comparison determination circuit.

According to the drive circuit according to this application example, when the rectifier circuit full-wave rectifies the input signal and outputs it, the voltage accuracy of the drive signal is improved, and when the rectifier circuit half-wave rectifies the input signal and outputs it. Does not require the inverting amplification operation of the input signal required for full-wave rectification, thus reducing power consumption. As described above, according to the drive circuit according to the present application example, high-precision operation or low power consumption operation can be selected.

[Application example 4]
In the drive circuit according to the above application example, the second reference voltage may be lower when the rectifier circuit functions as a half-wave rectifier circuit than when the rectifier circuit functions as a full-wave rectifier circuit. ..

In the drive circuit according to this application example, when the rectifier circuit functions as a half-wave rectifier circuit, the output voltage of the rectifier circuit is lower than when it functions as a full-wave rectifier circuit. Therefore, according to the drive circuit according to this application example, when the rectifier circuit functions as a half-wave rectifier circuit, the rectifier circuit can be made by lowering the second reference voltage as compared with the case where it functions as a full-wave rectifier circuit. Since the difference in the judgment result of the comparison judgment circuit between the case of functioning as the full-wave rectifier circuit and the case of functioning as the half-wave rectifier circuit becomes small, the amplitude difference of the drive signal can be made small.

[Application example 5]
The drive circuit according to the above application example includes a reference voltage circuit having a first resistance, and the case where the rectifier circuit functions as a half-wave rectifier circuit is better than the case where the rectifier circuit functions as a full-wave rectifier circuit. The current flowing through the first resistor is small, and the second reference voltage may be the voltage at one end of the first resistor.

According to the drive circuit according to the present application example, in the reference voltage circuit, the second reference voltage can be made variable by a simple configuration by making the current flowing through the first resistor variable.

[Application example 6]
In the drive circuit according to the above application example, the gain of the comparison determination circuit may be smaller when the rectifier circuit functions as a half-wave rectifier circuit than when the rectifier circuit functions as a full-wave rectifier circuit. ..

In the drive circuit according to this application example, when the rectifier circuit functions as a half-wave rectifier circuit, the output signal of the rectifier circuit contains an unnecessary signal component having a lower frequency component than when it functions as a full-wave rectifier circuit. .. Therefore, according to the drive circuit according to this application example, when the rectifier circuit functions as a half-wave rectifier circuit, the rectifier circuit has a smaller gain of the comparison judgment circuit than when it functions as a full-wave rectifier circuit. In both the case of functioning as a full-wave rectifier circuit and the case of functioning as a half-wave rectifier circuit, the comparison determination circuit can similarly reduce unnecessary signal components included in the output signal of the rectifier circuit.

[Application 7]
In the drive circuit according to the above application example, the cutoff frequency of the comparison determination circuit is lower when the rectifier circuit functions as a half-wave rectifier circuit than when the rectifier circuit functions as a full-wave rectifier circuit. May be good.

In the drive circuit according to this application example, when the rectifier circuit functions as a half-wave rectifier circuit, the output signal of the rectifier circuit contains an unnecessary signal component having a lower frequency component than when it functions as a full-wave rectifier circuit. .. Therefore, according to the drive circuit according to this application example, when the rectifier circuit functions as a half-wave rectifier circuit, it is rectified by lowering the cutoff frequency of the comparison judgment circuit than when it functions as a full-wave rectifier circuit. Whether the circuit functions as a full-wave rectifier circuit or a half-wave rectifier circuit, the comparison determination circuit can similarly reduce unnecessary signal components included in the output signal of the rectifier circuit.

[Application Example 8]
The physical quantity detection device according to this application example includes any of the above drive circuits, a physical quantity detection element driven by the drive signal, and a detection circuit that generates a physical quantity signal based on an output signal of the physical quantity detection element. It has.

According to the physical quantity detection device according to this application example, since the drive circuit capable of selecting high-precision operation or low power consumption operation is provided, for example, it is possible to realize a physical quantity detection device capable of low power consumption operation. Is.

[Application 9]
The electronic device according to this application example includes the above-mentioned physical quantity detecting device.

[Application Example 10]
The moving body according to this application example includes the above-mentioned physical quantity detecting device.

According to these application examples, since the physical quantity detection device capable of selecting high-precision operation or low power consumption operation is provided, for example, it is possible to realize an electronic device and a mobile body capable of low power consumption operation. is there.

The functional block diagram of the physical quantity detection apparatus of this embodiment. Top view of the vibrating piece of the physical quantity detecting element. The figure for demonstrating the operation of a physical quantity detection element. The figure for demonstrating the operation of a physical quantity detection element. The figure which shows the structural example of the drive circuit in 1st Embodiment. The figure which shows the structural example of the reference voltage circuit. The figure which shows an example of the signal waveform in the drive circuit when a rectifier circuit functions as a full-wave rectifier circuit. The figure which shows an example of the signal waveform in the drive circuit when a rectifier circuit functions as a half-wave rectifier circuit. The figure which shows the structural example of the drive circuit in 2nd Embodiment. The figure which shows the structural example of the drive circuit in 3rd Embodiment. The figure which shows the structural example of the drive circuit in 4th Embodiment. The functional block diagram which shows an example of the structure of the electronic device of this embodiment. The perspective view which shows typically the digital camera which is an example of an electronic device. The figure which shows an example of the moving body of this embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the embodiments described below do not unreasonably limit the contents of the present invention described in the claims. Moreover, not all of the configurations described below are essential constituent requirements of the present invention.

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

1. 1. Physical quantity detector 1-1. 1st Embodiment FIG. 1 is a functional block diagram of the physical quantity detection device of this embodiment. The physical quantity detection device 1 of the present embodiment includes a physical quantity detection element (sensor element) 2 for outputting an analog signal related to the physical quantity and a signal processing circuit 3.

The physical quantity detecting element 2 has a vibrating piece in which a driving electrode and a detecting electrode are arranged, and in general, the vibrating piece is ensured to be airtight in order to reduce the impedance of the vibrating piece as much as possible and increase the oscillation efficiency. It is sealed in the package. In the present embodiment, the physical quantity detecting element 2 has a so-called double T-shaped vibrating piece having two T-shaped driving vibrating arms.

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

As shown in FIG. 2, in the vibrating piece of the physical quantity detecting element 2, the driving vibrating arms 101a and 101b extend from the two driving bases 104a and 104b in the + Y-axis direction and the −Y-axis direction, respectively. Drive electrodes 112 and 113 are formed on the side surface and the upper surface of the drive vibrating arm 101a, respectively, and drive electrodes 113 and 112 are formed on the side surface and the upper surface of the drive vibration arm 101b, respectively. The drive electrodes 112 and 113 are connected to the drive circuit 20 via the DS terminal and the DG terminal of the signal processing circuit 3 shown in FIG. 1, respectively.

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

The detection vibrating arm 102 extends from the detection base 107 in the + Y-axis direction and the −Y-axis direction. 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 vibration arm 102. The detection electrodes 114 and 115 are connected to the detection circuit 30 via the S1 terminal and the S2 terminal of the signal processing circuit 3 shown in FIG. 1, respectively. Further, the common electrode 116 is grounded.

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

In this state, when an angular velocity with the Z axis as the rotation axis is applied to the vibrating piece of the physical quantity detecting element 2, the drive vibrating arms 101a and 101b coriolis in the direction perpendicular to both the bending vibration direction of the arrow B and the Z axis. Get the power of. As a result, as shown in FIG. 4, the connecting arms 105a and 105b vibrate as shown by the arrow C. Then, the detection vibrating arm 102 bends and vibrates as shown by the arrow D in conjunction with the vibration (arrow C) of the connecting arms 105a and 105b. The bending vibration of the detected vibrating arm 102 and the bending vibration (exciting vibration) of the driving vibrating arms 101a and 101b due to the Coriolis force are out of phase by 90 °.

By the way, if the magnitude of the vibration energy or the magnitude of the vibration amplitude when the drive vibration arms 101a and 101b perform bending vibration (excitation vibration) is equal to the two drive vibration arms 101a and 101b, the drive vibration arms 101a, The detection vibrating arm 102 does not bend and vibrate when the vibration energy of 101b is balanced and the physical quantity detecting element 2 is not subjected to angular velocity. However, if the vibration energies of the two drive vibration arms 101a and 101b are out of balance, bending vibration is generated in the detection vibration arm 102 even when the physical quantity detection element 2 is not subjected to an angular velocity. This bending vibration is called leakage vibration, which is the bending vibration of arrow D like the vibration based on the Coriolis force, but has the same phase as the drive signal.

Then, due to the piezoelectric effect, AC charges based on these bending vibrations are generated at the detection electrodes 114 and 115 of the detection vibration arm 102. Here, the AC charge generated based on the Coriolis force changes according to the magnitude of the Coriolis force (in other words, the magnitude of the angular velocity applied to the physical quantity detecting element 2). On the other hand, the AC charge generated based on the leakage vibration is constant regardless of the magnitude of the angular velocity applied to the physical quantity detecting element 2.

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

As described above, the physical quantity detecting element 2 detects the AC charge (angular velocity component) based on the Coriolis force and the AC charge (vibration leakage component) based on the leakage vibration of the excitation vibration with the Z axis as the detection axis. Output via 115. The physical quantity detecting element 2 functions as an angular velocity sensor that detects the angular velocity.

Returning to FIG. 1, the signal processing circuit 3 of the present embodiment includes a reference voltage circuit 10, a drive circuit 20, a detection circuit 30, a clock generation circuit 50, a storage unit 60, and an interface circuit 70. It may be a one-chip integrated circuit (IC). The signal processing circuit 3 of the present embodiment may have a configuration in which some of these elements are omitted or changed, or other elements are added.

The reference voltage circuit 10 generates constant voltages and currents such as reference voltages VR1 and VR2 from the power supply voltage supplied from the VDD terminal of the signal processing circuit 3 and supplies them to the drive circuit 20 and the detection circuit 30.

The drive circuit 20 generates a drive signal DRV for driving (exciting and vibrating) the physical quantity detection element 2 and supplies the drive signal DRV to the drive electrode 112 of the physical quantity detection element 2 via the DS terminal. Further, in the drive circuit 20, the oscillation current generated in the drive electrode 113 due to the excitation vibration of the physical quantity detection element 2 is input via the DG terminal, and the amplitude of the drive signal DRV is maintained so that the amplitude of the oscillation current is kept constant. Feedback control of the level. Further, the drive circuit 20 generates a detection signal SDET having the same phase as the drive signal DRV, and outputs the detection signal SDET to the detection circuit 30.

The detection circuit 30 includes a QV amplifier 31, a variable gain amplifier (PGA: Programmable Gain Amplifier) 32, a synchronous detection circuit 33, an A / D (Analog to Digital) conversion circuit 34, and a DSP (Digital Signal Processor) 35. ing. The detection circuit 30 of the present embodiment may have a configuration in which some of these elements are omitted or changed, or other elements are added.

The QV amplifier 31 receives an AC charge (detection current) including an angular velocity component and a vibration leakage component from the detection electrode 114 of the physical quantity detection element 2 via the S1 terminal, and generates a voltage signal corresponding to the AC charge. Let me. Further, in the QV amplifier 31, an AC charge (detection current) including an angular velocity component and a vibration leakage component is input from the detection electrode 115 of the physical quantity detection element 2 via the S2 terminal, and a voltage signal corresponding to the AC charge is input. To generate. The AC charge input from the detection electrode 114 to the QV amplifier 31 and the AC charge input from the detection electrode 115 to the QV amplifier 31 are in opposite phase (phase difference is 180 °), and the two outputs from the QV amplifier 31. The signals are also out of phase with each other.

The variable gain amplifier 32 amplifies or attenuates the two signals output from the QV amplifier 31, respectively, and outputs two signals having a desired voltage level. The two signals output from the variable gain amplifier 32 are out of phase with each other.

The synchronous detection circuit 33 uses the detection signal SDET output by the drive circuit 20 to synchronously detect angular velocity components included in each of the two signals (detected signals) output from the variable gain amplifier 32. For example, when the detection signal SDET is at a high level, the synchronous detection circuit 33 outputs two signals output from the variable gain amplifier 32 as they are, and when the detection signal SDET is at a low level, it is output from the variable gain amplifier 32. It can be configured as a circuit that outputs two signals obtained by inverting the two signals with respect to the reference voltage VR1.

The A / D conversion circuit 34 operates in synchronization with the clock signal ADCCLK, converts the voltage value of the difference signal between the two signals output by the synchronous detection circuit 33 into digital data (angle velocity data), and outputs the voltage value. The digital data output from the A / D conversion circuit 34 is sequentially updated at a predetermined rate (for example, 1.5 kHz). The A / D conversion circuit 34 may be, for example, a delta-sigma type or a sequential comparison type A / D conversion circuit.

The DSP 35 operates in synchronization with the clock signal DSPCLK, and performs processing such as filtering digital data (angular velocity data) output from the A / D conversion circuit 34. In order to realize high-speed digital filtering processing by the DSP 35, the frequency of the clock signal DSPCLK is sufficiently higher than the output rate (for example, 1.5 kHz) of the A / D conversion circuit 34, for example, about 400 kHz. The value of the digital data output from the DSP 35 represents the angular velocity detected by the physical quantity detecting element 2, and is sequentially updated at a predetermined rate (for example, 1.5 kHz).

Then, the digital data output from the DSP 35 becomes the output data of the detection circuit 30. As described above, the detection circuit 30 is a circuit that generates and outputs digital data (angular velocity data) as a physical quantity signal based on the output signal of the physical quantity detection element 2.

The clock generation circuit 50 generates the clock signal ADCCLK and the clock signal DSPCLK. For example, the clock generation circuit 50 may be a CR oscillator, a ring oscillator, or the like.

The storage unit 60 has a register 61 and a non-volatile memory 62. Digital data (angular velocity data) or the like output by the detection circuit 30 (DSP35) is stored in the register 61.

The non-volatile memory 62 stores various information such as various trimming data (adjustment data and correction data) for the drive circuit 20 and the detection circuit 30. The non-volatile memory 62 can be configured as, for example, a MONOS (Metal Oxide Nitride Oxide Silicon) type memory or an EEPROM (Electrically Erasable Programmable Read-Only Memory).

Further, when the power of the signal processing circuit 3 is turned on (when the voltage of the VDD terminal rises from 0 V to a desired voltage), various trimming data stored in the non-volatile memory 62 are transferred to the register 61 and held. Various trimming data held in the register 61 are supplied to the drive circuit 20 and the detection circuit 30.

The interface circuit 70 is electrically connected to the XCS terminal, the SCLK terminal, the MOSI terminal, and the MISO terminal, and is a circuit for communicating with an external device via these terminals. In communication via the interface circuit 70, the external device functions as a master, and the physical quantity detection device 1 (signal processing circuit 3) functions as a slave. Then, the external device writes data to a predetermined address of the register 61 via the interface circuit 70, reads data (for example, angular velocity data) from the predetermined address of the register 61, and transmits various commands. The operation of the signal processing circuit 3 can be controlled. Interface circuit 70, for example, 4 is a SPI (Serial Peripheral Interface) interface circuit of the terminals may be ^{I 2 C (Inter-Integrated Circuit} ) interface circuit SPI interface circuit and second terminal of the three terminal.

FIG. 5 is a diagram showing a configuration example of the drive circuit 20. 5, the driving circuit 20, I / V conversion circuit 21, a low pass filter 22, high pass filter 23, a comparator 24, a rectifier circuit 25, is configured to include a comparison determination circuit 26 and the comparator 2 7 There is. The drive circuit 20 of the present embodiment may have a configuration in which some of these elements are omitted or changed, or other elements are added.

I / V conversion circuit 21, a low pass filter 22, high pass filter 23, a comparator 24, a rectifier circuit 25 and the comparator 2 7 operates based on the reference voltage VR1 supplied from the reference voltage circuit 10. The reference voltage VR1 is an analog ground voltage, which is, for example, a voltage halved from the power supply voltage supplied from the VDD terminal. Further, the comparison determination circuit 26 operates with reference to the reference voltage VR2 supplied from the reference voltage circuit 10.

The I / V conversion circuit 21 converts the oscillating current generated by the excitation vibration of the physical quantity detection element 2 and input via the DG terminal into an AC voltage signal.

The low-pass filter 22 removes high-frequency components of the output signal of the I / V conversion circuit 21, and the high-pass filter 23 removes low-frequency components (offset and the like) of the output signal of the low-pass filter 22. A bandpass filter is formed by the lowpass filter 22 and the highpass filter 23, and a signal generated by the excitation vibration of the physical quantity detecting element 2 is passed through.

The comparator 24 compares the voltage of the output signal of the high-pass filter 23 with the reference voltage VR1 to generate a binarized signal. In this binarized signal, the high level voltage is the output voltage of the comparison determination circuit 26, and the low level voltage is the ground voltage (0V). Then, the output signal of the comparator 24 is supplied to the physical quantity detecting element 2 as a drive signal DRV via the DS terminal. By matching the frequency (drive frequency) of the drive signal DRV with the resonance frequency of the physical quantity detection element 2, the physical quantity detection element 2 can be stably oscillated.

The comparator 27 amplifies the voltage of the output signal of the high-pass filter 23 to generate a binarized signal (square wave voltage signal), and outputs it as a detection signal SDET. In this detection signal SDET, the high level voltage is the power supply voltage and the low level voltage is the ground voltage (0V).

The rectifier circuit 25 rectifies the output signal of the I / V conversion circuit 21 and outputs a DC signal. In the present embodiment, the rectifier circuit 25 includes a comparator 251, an operational amplifier 252, a resistor 253, a resistor 254, a switch 255, a switch 256, a switch 257, and a switch 258.

The comparator 251 uses the output signal of the I / V conversion circuit 21 as an input signal, and compares the input signal with the reference voltage VR1 (an example of “threshold voltage”).

The operational amplifier 252, the resistor 253, and the resistor 254 form an inverting amplifier circuit, and the output signal of the I / V conversion circuit 21 is input as an input signal, and the input signal is input from the output terminal of the operational amplifier 252 with reference to the reference voltage VR1. Outputs a signal with inverted voltage.

One end of the switch 255 is connected to the output terminal of the inverting amplifier circuit (the output terminal of the operational amplifier 252), and the other end is connected to one end of the switch 258. A reference voltage VR1 is input to one end of the switch 256, and the other end is connected to one end of the switch 258. One of the switch 255 and the switch 256 becomes conductive and the other becomes non-conducting according to the voltage level of the control signal SEL. In FIG. 5, when the control signal SEL is at a low level, the switch 255 is conductive and the switch 256 is non-conducting, and when the control signal SEL is at a high level, the switch 256 is conducting and the switch 255 is non-conducting. Therefore, the output signal of the inverting amplifier circuit (output signal of the operational amplifier 252) is supplied to one end of the switch 258 when the control signal SEL is low level, and the reference voltage VR1 is supplied when the control signal SEL is high level. Will be done. That is, the switch 255 and the switch 256 use either the output signal of the inverting amplifier circuit (output signal of the operational amplifier 252) or the reference voltage VR1 (an example of the "first reference voltage") based on the control signal SEL. It functions as a first selection circuit that selects and outputs.

One end of the switch 257 is connected to the output terminal of the I / V conversion circuit 21, and the other end is connected to the input terminal of the comparison determination circuit 26 (one end of the resistor 262). One end of the switch 258 is connected to the output terminal of the first selection circuit (the other end of the switch 255 and the other end of the switch 256), and the other end is connected to the input terminal of the comparison determination circuit 26 (one end of the resistor 262). ing. One of the switch 257 and the switch 258 becomes conductive and the other becomes non-conducting depending on the voltage level of the output signal of the comparator 251. In FIG. 5, when the output signal of the comparator 251 is high level, the switch 257 is conductive and the switch 258 is non-conducting, and when the control signal SEL is low level, the switch 258 is conducting and the switch 257 is non-conducting. Become. Therefore, when the output signal of the comparator 251 is at a high level, the output signal of the I / V conversion circuit 21 (input signal of the rectifying circuit 25) is supplied to the input terminal (one end of the resistor 262) of the comparison determination circuit 26. When the output signal of the comparator 251 is low level, the output signal of the first selection circuit composed of the switch 255 and the switch 256 is supplied. That is, the switch 257 and the switch 258 use either the output signal of the I / V conversion circuit 21 (the input signal of the rectifier circuit 25) or the output signal of the first selection circuit based on the output signal of the comparator 251. It functions as a second selection circuit that selects and outputs.

In the rectifying circuit 25 of the present embodiment configured as described above, when the control signal SEL is at a low level, the voltage of the output signal (input signal of the rectifying circuit 25) of the I / V conversion circuit 21 is higher than the reference voltage VR1. If it is high, the output voltage of the I / V conversion circuit 21 is output, and if the voltage of the output signal (input signal of the rectifying circuit 25) of the I / V conversion circuit 21 is lower than the reference voltage VR1, the I / V conversion circuit 21 The output voltage is inverted with respect to the reference voltage VR1. That is, when the control signal SEL is at a low level, the rectifier circuit 25 functions as a full-wave rectifier circuit.

Further, the rectifying circuit 25 has an I / V conversion circuit 21 if the voltage of the output signal (input signal of the rectifying circuit 25) of the I / V conversion circuit 21 is higher than the reference voltage VR1 when the control signal SEL is at a high level. If the voltage of the output signal (input signal of the rectifying circuit 25) of the I / V conversion circuit 21 is lower than the reference voltage VR1, the reference voltage VR1 is output. That is, when the control signal SEL is at a high level, the rectifier circuit 25 functions as a half-wave rectifier circuit. When the control signal SEL is at a high level, the operation of the operational amplifier 252 is stopped because the inverting amplifier circuit composed of the operational amplifier 252, the resistor 253, and the resistor 254 is unnecessary.

Thus, the rectifier circuit 25 in this embodiment, whether the function of the input signal as a half-wave rectifier circuit that outputs or inputs signal functions as a full wave rectifier circuit for outputting the full-wave rectification and half-wave rectification , It can be switched by the control signal SEL. For example, data for setting the control signal SEL to a high level or a low level may be stored in the non-volatile memory 62 of the storage unit 60, or an external device may store the register of the storage unit 60 via the interface circuit 70. Data for setting the control signal SEL to a high level or a low level may be written in 61.

The comparison determination circuit 26 includes an operational amplifier 261 and a resistor 262 and a capacitor 263. In the operational amplifier 261, the output signal of the rectifier circuit is input to the inverting input terminal (-terminal) via the resistor 262, the reference voltage VR2 is input to the non-inverting input terminal (+ terminal), and the output signal (charge) is It is stored in the capacitor 263.

The comparison determination circuit 26 configured in this way is a complete integrator that integrates and outputs the output voltage of the rectifying circuit 25 with reference to the reference voltage VR2, in other words, integrates the output voltage of the rectifying circuit 25. This is a circuit for determining whether the obtained voltage is higher or lower than the reference voltage VR2 (an example of the "second reference voltage"). The output voltage of the comparison determination circuit 26 decreases as the output voltage of the rectifier circuit 25 increases (the amplitude of the output signal of the I / V conversion circuit 21 increases). Therefore, the larger the oscillation amplitude, the lower the high-level voltage of the output signal (drive signal DRV) of the comparator 24, and the smaller the oscillation amplitude, the higher the high-level voltage of the output signal (drive signal DRV) of the comparator 24. Therefore, automatic gain control (AGC: Auto Gain Control) is applied so that the oscillation amplitude is kept constant. Therefore, the comparator 24 functions as a drive signal generation circuit that generates a drive signal DRV whose amplitude is adjusted based on the determination result of the comparison determination circuit 26.

The comparison determination circuit 26 also functions as a low-pass filter having a transfer function H (s) represented by the equation (1). Then, from the equation (1), the gain of the comparison determination circuit 26 is determined by the resistance value R ₁ of the resistor 262 and the capacitance value C _{1 of the} capacitor 263. Assuming that the capacitance value C ₁ is constant, the smaller the resistance value R ₁ , the smaller the comparison. gain of the decision circuit 26 is large, the gain of the higher resistance value R ₁ is greater comparison determining circuit 26 is small.

Here, the output signal of the rectifier circuit 25 when the control signal SEL is at a low level and the rectifier circuit 25 functions as a full-wave rectifier circuit is represented by the equation (2). Further, the output signal of the rectifier circuit 25 when the control signal SEL is at a high level and the rectifier circuit 25 functions as a half-wave rectifier circuit is represented by the equation (3). In the equations (2) and (3), the sine wave sinx is an input signal of the rectifier circuit 25.

Therefore, when the rectifier circuit 25 functions as a full-wave rectifier circuit, the signal component corresponding to the second term on the right side of the equation (2) in the output signal of the rectifier circuit 25 is attenuated by the integration process and the filter process in the comparison determination circuit 26. The output signal of the comparison determination circuit 26 becomes a DC signal corresponding to the first term (2 / π) on the right side of the equation (2). Similarly, when the rectifier circuit 25 functions as a half-wave rectifier circuit, the integration process and the filter process in the comparison determination circuit 26 correspond to the second and third terms on the right side of the equation (3) in the output signal of the rectifier circuit 25. The signal component is attenuated, and the output signal of the comparison determination circuit 26 becomes a DC signal corresponding to the first term (1 / π) on the right side of the equation (3).

Here, since the first term (1 / π) on the right side of the equation (3) is half of the first term (2 / π) on the right side of the equation (2), if the reference voltage VR2 is fixed, the rectifier circuit 25 The output voltage when functioning as a half-wave rectifier circuit is half the output voltage when the rectifier circuit 25 functions as a full-wave rectifier circuit. As a result, the amplitude of the output signal (drive signal DRV) of the comparator 24 when the rectifier circuit 25 functions as a half-wave rectifier circuit is also halved, and the drive capability of the physical quantity detection element 2 by the drive signal DRV is halved.

Therefore, in the present embodiment, the reference voltage VR2 is set to be lower when the rectifier circuit 25 functions as a half-wave rectifier circuit than when the rectifier circuit 25 functions as a full-wave rectifier circuit. For example, with reference to the reference voltage VR1, the reference voltage VR2 when the rectifier circuit 25 functions as a half-wave rectifier circuit becomes 1/2 of the reference voltage VR2 when the rectifier circuit 25 functions as a full-wave rectifier circuit. It may be.

FIG. 6 is a diagram showing a configuration example of the reference voltage circuit 10. As shown in FIG. 6, the reference voltage circuit 10 includes a bias circuit 11, NMOS transistors 12, 13 and analog switches 14, 15 and a resistor 16 (an example of a “first resistor”).

The bias circuit 11 includes a constant current source 11a, NMOS transistors 11b and 11c, and a MOSFET transistor 11d. The NMOS transistor 11b and the NMOS transistor 11c form a current mirror circuit, and a current I ₀ having the same magnitude as the current flowing through the constant current source 11a flows through the MIMO transistor 11d, and the bias voltage determined by this current I ₀ is determined by the current I ₀ . It is supplied to each of the gate terminals of 13.

Since the control signal CTL 1 of the analog switch 14 is fixed at a low level and the analog switch 14 is always conductive, a current I ₁ determined by the bias voltage flows through the NMOS transistor 12. On the other hand, the voltage level of the control signal CTL 2 of the analog switch 15 changes in conjunction with the voltage level of the control signal SEL. Specifically, if the control signal SEL is at a low level, the control signal CTL 2 is also at a low level and the analog switch 15 conducts, so that a current I ₂ determined by the bias voltage flows through the epitaxial transistor 13 and the control signal SEL If is high level, the control signal CTL 2 also becomes high level and the analog switch 15 becomes non-conducting, so that no current flows through the epitaxial transistor 13.

Therefore, when the control signal SEL is low level (when the rectifier circuit 25 functions as a full-wave rectifier circuit), the current flowing from one end to the other end of the resistor 16 is I ₁ + I ₂ , and when the control signal SEL is high level. (When the rectifier circuit 25 functions as a half-wave rectifier circuit), the current flowing from one end to the other end of the resistor 16 is I ₁ . The reference voltage VR2 is the voltage at one end of the resistor 16. As described above, the reference voltage VR2 is lower when the rectifier circuit 25 functions as a half-wave rectifier circuit than when the rectifier circuit 25 functions as a full-wave rectifier circuit because the current flowing through the resistor 16 is smaller. In this way, the reference voltage VR2 can be changed by the reference voltage circuit 10 having a simple configuration.

FIG. 7 is a diagram showing an example of a signal waveform in the drive circuit 20 when the rectifier circuit 25 functions as a full-wave rectifier circuit. Further, FIG. 8 is a diagram showing an example of a signal waveform in the drive circuit 20 when the rectifier circuit 25 functions as a half-wave rectifier circuit. 7 and 8 show the signal waveforms at points A to F in FIG. As shown in FIGS. 7 and 8, when the rectifier circuit 25 functions as a half-wave rectifier circuit, the reference voltage VR2 is lower than that when the rectifier circuit 25 functions as a full-wave rectifier circuit. (Output voltage of the comparison determination circuit 26) is almost the same. Therefore, regardless of whether the rectifier circuit 25 functions as a full-wave rectifier circuit or a half-wave rectifier circuit, the voltage at point E (amplitude of the drive signal DRV) is almost the same, and the drive capability of the physical quantity detection element 2 is increased. There is no difference.

As described above, in the physical quantity detection device 1 of the first embodiment, whether the rectifier circuit 25 functions as a full-wave rectifier circuit or a half-wave rectifier circuit in the drive circuit 20 based on the control signal SEL. Can be switched. When the control signal SEL is set so that the rectifier circuit 25 functions as a full-wave rectifier circuit, the voltage accuracy of the output signal and the drive signal DRV of the rectifier circuit 25 is improved, and the rectifier circuit 25 is a half-wave rectifier circuit. When the control signal SEL is set so as to function as, the power consumption is reduced because the inverting amplification operation of the input signal required for full-wave rectification is not required. As described above, according to the first embodiment, it is possible to select the high-precision operation or the low power consumption operation of the rectifier circuit 25 and the drive circuit 20, and to realize the physical quantity detection device 1 capable of the low power consumption operation. It is possible.

Further, according to the physical quantity detection device 1 of the first embodiment, in the drive circuit 20, when the rectifier circuit 25 functions as a half-wave rectifier circuit, the reference voltage VR2 is lowered as compared with the case where the rectifier circuit 25 functions as a full-wave rectifier circuit. As a result, the difference in the output voltage of the comparison judgment circuit 26 between the case where the rectifier circuit 25 functions as a full-wave rectifier circuit and the case where it functions as a half-wave rectifier circuit becomes small, so that the amplitude difference of the drive signal DRV should be made small. Can be done. As a result, the voltage accuracy of the drive signal DRV can be kept constant regardless of whether the rectifier circuit 25 functions as a full-wave rectifier circuit or a half-wave rectifier circuit.

1-2. Second Embodiment In the physical quantity detection device 1 of the first embodiment, in the drive circuit 20, the output signal of the rectifier circuit 25 when the rectifier circuit 25 functions as a half-wave rectifier circuit is the second term on the right side of the equation (3) (3). whereas a signal component of 1 / 2sinx), the output signal of the rectifier circuit 25 when the rectifier circuit 25 functions as a full-wave rectifier circuit does not include the frequency component. Then, if the gain of the comparison determination circuit 26 is too large, when the rectifier circuit 25 functions as a half-wave rectifier circuit, the signal component of the second term (1/2 sinx) on the right side of the equation (3) is sufficiently provided in the comparison determination circuit 26. Cannot be attenuated to. Further, in order to rectifier circuit 25 is sufficiently attenuate the signal component of the second term (1 / SiNx) of formula (3) in the case of functioning as a half-wave rectifier circuit, the resistance value R ₁ of the resistor 262 is increased If the gain of the comparison determination circuit 26 is reduced, the current consumption of the resistor 262 when the rectifier circuit 25 functions as a full-wave rectifier circuit is unnecessarily increased.

Therefore, in the physical quantity detection device 1 of the second embodiment, the drive circuit 20 is compared and determined when the rectifier circuit 25 functions as a half-wave rectifier circuit rather than when the rectifier circuit 25 functions as a full-wave rectifier circuit. The gain of the circuit 26 is configured to be small.

Hereinafter, regarding the physical quantity detection device 1 of the second embodiment, the same components as those of the first embodiment are designated by the same reference numerals, the description overlapping with the first embodiment is omitted, and the contents different from those of the first embodiment are described. explain.

FIG. 9 is a diagram showing a configuration example of the drive circuit 20 in the physical quantity detection device 1 of the second embodiment. As shown in FIG. 9 , the drive circuit 20 in the second embodiment has a switch 264 and a resistor 265 in series with the resistor 262 in the comparison determination circuit 26 with respect to the drive circuit 20 (FIG. 5) in the first embodiment. A parallel circuit with is added. The switch 264 conducts when the control signal SEL is at a low level and becomes non-conducting when the control signal SEL is at a high level. That is, when the rectifier circuit 25 functions as a full-wave rectifier circuit, the switch 264 conducts and only the resistor 262 functions as an input resistor, and when the rectifier circuit 25 functions as a half-wave rectifier circuit, the switch 264 becomes non-conducting. The resistor 262 and the resistor 265 function as input resistors.

Therefore, assuming that the resistance value of the resistor 262 is R ₁ , the resistance value of the resistor 265 is R ₂ , and the capacitance value of the capacitor 263 is C ₁ , the transmission function of the comparison determination circuit 26 when the rectifier circuit 25 functions as a full-wave rectifier circuit. While H (s) is as shown in equation (1), the transfer function H (s) of the comparison determination circuit 26 when the rectifier circuit 25 functions as a half-wave rectifier circuit is as shown in equation (4). Become. Therefore, the gain of the comparison determination circuit 26 when the rectifier circuit 25 functions as a half-wave rectifier circuit is R ₁ / (R ₁ + R) of the gain of the comparison determination circuit 26 when the rectifier circuit 25 functions as a full-wave rectifier circuit. ₂ ) It becomes twice as small.

As described above, according to the physical quantity detection device 1 of the second embodiment, the same effect as that of the first embodiment is obtained, and when the rectifier circuit 25 functions as a half-wave rectifier circuit in the drive circuit 20, all By making the gain of the comparison judgment circuit 26 smaller than that of the case where the rectifier circuit 26 functions as a wave rectifier circuit, the comparison judgment circuit 26 can be used regardless of whether the rectifier circuit 25 functions as a full-wave rectifier circuit or a half-wave rectifier circuit. Unnecessary signal components included in the output signal of the rectifier circuit 25 can be similarly reduced. As a result, the voltage accuracy of the drive signal DRV can be kept constant regardless of whether the rectifier circuit 25 functions as a full-wave rectifier circuit or a half-wave rectifier circuit.

1-3. Third Embodiment In the physical quantity detection device 1 of the first embodiment, in the drive circuit 20, the comparison determination circuit 26 is configured as a complete integrator, but may be configured as an incomplete integrator.

Hereinafter, regarding the physical quantity detecting device 1 of the third embodiment, the same components as those of the first embodiment are designated by the same reference numerals, the description overlapping with the first embodiment is omitted, and the contents different from those of the first embodiment are described. explain.

FIG. 10 is a diagram showing a configuration example of the drive circuit 20 in the physical quantity detection device 1 of the third embodiment. As shown in FIG. 10, in the drive circuit 20 of the third embodiment, a resistor 266 is added in parallel with the capacitor 263 in the comparison determination circuit 26 with respect to the drive circuit 20 (FIG. 5) of the first embodiment. There is.

The comparison determination circuit 26 configured in this way is an incomplete integrator that integrates and outputs the output voltage of the rectifier circuit 25 with reference to the reference voltage VR2.

The comparison decision circuit 26, as shown in equation (5), also functions as a low pass filter having a cutoff frequency _{f c} determined by the resistance _{R 3} of the capacitance value _{C 1} and the resistor 266 of capacitor 263.

Therefore, when the rectifier circuit 25 functions as a full-wave rectifier circuit, the signal component corresponding to the second term on the right side of the equation (2) in the output signal of the rectifier circuit 25 is attenuated by the integration process and the filter process in the comparison determination circuit 26. The output signal of the comparison determination circuit 26 becomes a DC signal corresponding to the first term (2 / π) on the right side of the equation (2). Similarly, when the rectifier circuit 25 functions as a half-wave rectifier circuit, the integration process and the filter process in the comparison determination circuit 26 correspond to the second and third terms on the right side of the equation (3) in the output signal of the rectifier circuit 25. The signal component is attenuated, and the output signal of the comparison determination circuit 26 becomes a DC signal corresponding to the first term (1 / π) on the right side of the equation (3).

According to the physical quantity detecting device 1 of the third embodiment configured in this way, the same effect as that of the first embodiment can be obtained.

1-4. Fourth Embodiment In the physical quantity detection device 1 of the third embodiment, in the drive circuit 20, the output signal of the rectifier circuit 25 when the rectifier circuit 25 functions as a half-wave rectifier circuit is the second term on the right side of the equation (3) (3). whereas a signal component of 1 / 2sinx), the output signal of the rectifier circuit 25 when the rectifier circuit 25 functions as a full-wave rectifier circuit does not include the frequency component. Then, equation (5) cut-off frequency f _c of the comparison determining circuit 26 shown in is too high, the rectifier circuit 25 may function as a half-wave rectifier circuit, the right side second equation (3) in the comparison judgment circuit 26 The signal component of the term (1/2 sinx) cannot be sufficiently attenuated. Further, in order to sufficiently attenuate the signal component of the second term (1/2 sinx) on the right side of the equation (3) when the rectifier circuit 25 functions as a half-wave rectifier circuit, the resistance value R ₃ of the resistor 266 is increased. a lower cut-off frequency f _c of the comparison determining circuit 26 Te, rectifier circuit 25 is thereby unnecessarily increasing current consumption in the resistor 266 when functioning as a full-wave rectifier circuit.

Therefore, in the physical quantity detection device 1 of the fourth embodiment, the drive circuit 20 is compared and determined when the rectifier circuit 25 functions as a half-wave rectifier circuit rather than when the rectifier circuit 25 functions as a full-wave rectifier circuit. cut-off frequency f _c of the circuit 26 is configured to be lower.

Hereinafter, with respect to the physical quantity detection device 1 of the fourth embodiment, the same components as those of the first embodiment or the third embodiment are designated by the same reference numerals, and the description overlapping with the first embodiment or the third embodiment is omitted. Then, the contents different from the first embodiment and the third embodiment will be described.

FIG. 11 is a diagram showing a configuration example of the drive circuit 20 in the physical quantity detection device 1 of the fourth embodiment. As shown in FIG. 11, the drive circuit 20 in the fourth embodiment has a switch 267 and a resistor 268 in series with the resistor 266 in the comparison determination circuit 26 with respect to the drive circuit 20 (FIG. 10) in the third embodiment. A parallel circuit with is added. The switch 267 conducts when the control signal SEL is at a low level and becomes non-conducting when the control signal SEL is at a high level. That is, when the rectifier circuit 25 functions as a full-wave rectifier circuit, the switch 267 is conductive and only the resistor 266 functions as a feedback resistor, and when the rectifier circuit 25 functions as a half-wave rectifier circuit, the switch 267 is non-conducting. The resistor 266 and the resistor 268 function as feedback resistors.

Therefore, assuming that the resistance value of the resistor 266 is R ₃ , the resistance value of the resistor 268 is R ₄ , and the capacitance value of the condenser 263 is C ₁ , the cutoff of the comparison judgment circuit 26 when the rectifier circuit 25 functions as a full-wave rectifier circuit frequency f _c for become as shown in equation (5), the rectifier circuit 25 is cut-off frequency f _c of the comparison judgment circuit 26 when functioning as a half-wave rectifier circuit is as shown in equation (6).

As described above, according to the physical quantity detection device 1 of the fourth embodiment, the same effect as that of the third embodiment is obtained, and when the rectifier circuit 25 functions as a half-wave rectifier circuit in the drive circuit 20, all by lowering the cut-off frequency f _c of the comparison determination circuit 26 than when functioning as a wave rectifier circuit, even if the rectification circuit 25 also functions as a half-wave rectifier circuit when functioning as a full-wave rectifier circuit, the comparison determination In the circuit 26, unnecessary signal components included in the output signal of the rectifier circuit 25 can be similarly reduced. As a result, the voltage accuracy of the drive signal DRV can be kept constant regardless of whether the rectifier circuit 25 functions as a full-wave rectifier circuit or a half-wave rectifier circuit.

2. 2. Electronic device FIG. 12 is a functional block diagram showing an example of the configuration of the electronic device of the present embodiment. As shown in FIG. 12, the electronic device 300 of the present embodiment includes a physical quantity detection device 310, a control device (MCU) 320, an operation unit 330, a ROM (Read Only Memory) 340, a RAM (Random Access Memory) 350, and a communication unit. It is configured to include 360 and a display unit 370. The electronic device of the present embodiment may have a configuration in which some of the constituent elements (each part) of FIG. 12 are omitted or changed, or other constituent elements are added.

The physical quantity detection device 310 is a device that drives a physical quantity detection element (not shown) and generates and outputs a physical quantity signal based on the output signal of the physical quantity detection element. For example, acceleration, angular velocity, velocity, angular acceleration, and force. It may be an inertial measuring device that detects at least a part of a physical quantity such as, or it may be a tilt meter that measures a tilt angle. As the physical quantity detecting device 310, for example, the physical quantity detecting device 1 of the present embodiment described above can be applied.

The control device (MCU) 320 transmits a communication signal to the physical quantity detection device 310 according to a program stored in the ROM 340 or the like, and performs various calculation processes and control processes using the output data of the physical quantity detection device 310. In addition, the control device (MCU) 320 performs various processes according to the operation signal from the operation unit 330, processes for controlling the communication unit 360 for data communication with the external device, and displays various information on the display unit 370. Performs processing such as transmitting a display signal for making the display signal.

The operation unit 330 is an input device composed of operation keys, button switches, and the like, and outputs an operation signal corresponding to the operation by the user to the control device (MCU) 320.

The ROM 340 stores programs, data, and the like for the control device (MCU) 320 to perform various calculation processes and control processes.

The RAM 350 is used as a work area of the control device (MCU) 320, and includes programs and data read from the ROM 340, data input from the operation unit 330, calculation results executed by the control device (MCU) 320 according to various programs, and the like. Is temporarily memorized.

The communication unit 360 performs various controls for establishing data communication between the control device (MCU) 320 and the external device.

The display unit 370 is a display device composed of an LCD (Liquid Crystal Display) or the like, and displays various information based on a display signal input from the CPU 320. The display unit 370 may be provided with a touch panel that functions as an operation unit 330.

As the physical quantity detection device 310, for example, the physical quantity detection device 1 of the present embodiment described above is applied, and the rectifier circuit functions as a half-wave rectifier circuit in the drive circuit to realize an electronic device capable of low power consumption operation. be able to.

Various electronic devices can be considered as such an electronic device 300, for example, a personal computer (for example, a mobile personal computer, a laptop personal computer, a tablet personal computer), a mobile terminal such as a smartphone or a mobile phone, and the like. Digital cameras, inkjet ejection devices (for example, inkjet printers), storage area network devices such as routers and switches, local area network devices, mobile terminal base station devices, televisions, video cameras, video recorders, car navigation devices, real-time Clock devices, pagers, electronic notebooks (including those with communication functions), electronic dictionaries, calculators, electronic game devices, game controllers, word processors, workstations, videophones, security TV monitors, electronic binoculars, POS terminals, medical devices ( For example, electronic thermometer, blood pressure monitor, blood glucose meter, electrocardiogram measuring device, ultrasonic diagnostic device, electronic endoscope), fish finder, various measuring devices, instruments (for example, instruments for vehicles, aircraft, ships), flight simulator. , Head mount display, motion trace, motion tracking, motion controller, PDR (pedestrian position and orientation measurement) and the like.

FIG. 13 is a perspective view schematically showing a digital camera 1300 which is an example of the electronic device 300 of the present embodiment. Note that FIG. 13 also briefly shows the connection with an external device. Here, while a normal camera sensitizes a silver halide photographic film by the light image of the subject, the digital camera 1300 performs photoelectric conversion of the light image of the subject by an imaging element such as a CCD (Charge Coupled Device) and captures the image. Generate a signal (image signal).

A display unit 1310 is provided on the back surface of the case (body) 1302 of the digital camera 1300, and is configured to display based on an image pickup signal by a CCD. The display unit 1310 is a finder that displays a subject as an electronic image. Functions as. Further, on the front side (back side in the drawing) of the case 1302, a light receiving unit 1304 including an optical lens (imaging optical system), a CCD, and the like is provided. When the photographer confirms the subject image displayed on the display unit 1310 and presses the shutter button 1306, the image pickup signal of the CCD at that time is transferred and stored in the memory 1308. Further, in the digital camera 1300, a video signal output terminal 1312 and an input / output terminal 1314 for data communication are provided on the side surface of the case 1302. A television monitor 1430 is connected to the video signal output terminal 1312, and a personal computer 1440 is connected to the data communication input / output terminal 1314, respectively, as needed. Further, the imaging signal stored in the memory 1308 is output to the television monitor 1430 and the personal computer 1440 by a predetermined operation. The digital camera 1300 has a physical quantity detection device 310, and uses the output data of the physical quantity detection device 310 to perform processing such as camera shake correction.

3. 3. The moving body FIG. 14 is a view (top view) showing an example of the moving body of the present embodiment. The moving body 400 shown in FIG. 14 includes a physical quantity detecting device 410, 420, 430, a controller 440, 450, 460, a battery 470, and a navigation device 480. The moving body of the present embodiment may be configured by omitting a part of the constituent elements (each part) of FIG. 14 or adding other constituent elements.

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

The controllers 440, 450, and 460 transmit communication signals to the physical quantity detection devices 410, 420, and 430, respectively, and use the output data of the physical quantity detection devices 410, 420, and 430 to control the posture, roll prevention system, and brake. It is a control device that performs various controls such as a system.

The navigation device 480 displays various information such as the position and time of the moving body 400 on the display based on the output information of the built-in GPS receiver (not shown). Further, the navigation device 480 has a built-in physical quantity detection device 490, and even when the GPS radio wave does not reach, the position and orientation of the moving body 400 are calculated based on the output signal of the physical quantity detection device 490, and necessary information is required. Continues to be displayed.

The physical quantity detection devices 410, 420, 430, and 490 are devices that drive a physical quantity detection element (not shown) to generate and output a physical quantity signal based on the output signal of the physical quantity detection element, and are, for example, angular velocity sensors. , Acceleration sensor, speed sensor, tilt meter, etc.

For example, low power consumption operation is possible by applying the physical quantity detection device 1 of each of the above-described embodiments as the physical quantity detection devices 410, 420, 430, 490 and allowing the rectifier circuit to function as a half-wave rectifier circuit in the drive circuit. It is possible to realize a moving body.

Various moving bodies can be considered as such moving bodies 400, and examples thereof include automobiles (including electric vehicles), aircraft such as jet aircraft and helicopters, ships, rockets, and artificial satellites.

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

For example, in each of the above-described embodiments, the rectifier circuit applied to the drive circuit for driving the physical quantity detection element has been described as an example, but the rectifier circuit according to the present invention is other than the drive circuit for driving the physical quantity detection element. It can be applied to any circuit.

Further, for example, in the above-described embodiment, a physical quantity detecting device (angular velocity detecting device) including a physical quantity detecting element for detecting an angular velocity, an electronic device, and a moving body have been described as examples, but the present invention describes various physical quantities. It can also be applied to a physical quantity detecting device including a physical quantity detecting element to be detected, an electronic device, and a moving body. The physical quantity detected by the physical quantity detecting element is not limited to the angular velocity, and may be angular acceleration, acceleration, geomagnetism, inclination, or the like. Further, the vibrating piece of the physical quantity detecting element does not have to be a double T type, for example, a tuning fork type or a comb tooth type, or a sound piece type having a shape such as a triangular prism, a square prism, or a columnar prism. May be good. As a material for the vibrating piece of the physical quantity detecting element, instead of crystal (SiO ₂ ), for example, a piezoelectric single crystal such as lithium tantalate (LiTaO ₃ ) or lithium niobate (LiNbO ₃ ) or lead zirconate titanate is used. Piezoelectric materials such as piezoelectric ceramics such as (PZT) may be used, or silicon semiconductors may be used. Further, for example, the structure may be such that a piezoelectric thin film such as zinc oxide (ZnO) or aluminum nitride (AlN) sandwiched between driving electrodes is arranged on a part of the surface of the silicon semiconductor. Further, the physical quantity detecting element is not limited to the piezoelectric type element, and may be a vibration type element such as an electrokinetic type, a capacitance type, an eddy current type, an optical type, or a strain gauge type. Alternatively, the method of the physical quantity detecting element is not limited to the vibration type, and may be, for example, an optical type, a rotary type, or a fluid type.

The above-described embodiments and modifications are merely examples, and the present invention is not limited thereto. For example, it is also possible to appropriately combine each embodiment and each modification.

The present invention includes substantially the same configurations as those described in the embodiments (eg, configurations with the same function, method and result, or configurations with the same purpose and effect). The present invention also includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that exhibits the same action and effect as the configuration described in the embodiment or a configuration that can achieve the same object. The present invention also includes a configuration in which a known technique is added to the configuration described in the embodiment.

1 ... Physical quantity detection device, 2 ... Physical quantity detection element, 3 ... Signal processing circuit, 10 ... Reference voltage circuit, 11 ... Bias circuit, 11a ... Constant current source, 11b, 11c ... NMOS transistor, 11d ... NMOS transistor, 12, 13 ... MPLS transistor, 14, 15 ... analog switch, 16 ... resistor, 20 ... drive circuit, 21 ... I / V conversion circuit, 22 ... low pass filter, 23 ... high pass filter, 24 ... comparator, 25 ... rectifier circuit, 26 ... Comparison judgment circuit, 27 ... comparator, 30 ... detection circuit, 31 ... QV amplifier, 32 ... variable gain amplifier, 33 ... synchronous detection circuit, 34 ... A / D conversion circuit, 35 ... DSP, 50 ... clock generation circuit, 60 ... Storage unit, 61 ... Register, 62 ... Non-volatile memory, 70 ... Interface circuit, 101a, 101b ... Drive vibration arm, 102 ... Detection vibration arm, 103 ... Weight part, 104a, 104b ... Drive base, 105a, 105b ... Connecting arm, 106 ... Weight, 107 ... Detection base, 112, 113 ... Drive electrode, 114, 115 ... Detection electrode, 116 ... Common electrode, 251 ... Comparator, 252 ... Operation amplifier, 253 ... Resistance, 254 ... Resistance , 255 ... switch, 256 ... switch, 257 ... switch, 258 ... switch, 261 ... operational amplifier, 262 ... resistance, 263 ... condenser, 264 ... switch, 265 ... resistance, 266 ... resistance, 267 ... switch, 268 ... resistance, 300 ... Electronic equipment, 310 ... Physical quantity detection device, 320 ... Control device (MCU), 330 ... Operation unit, 340 ... ROM, 350 ... RAM, 360 ... Communication unit, 370 ... Display unit, 400 ... Mobile unit, 410,420 , 430 ... Physical quantity detector, 440, 450, 460 ... Controller, 470 ... Battery, 480 ... Navigation device, 490 ... Physical quantity detector, 1300 ... Digital camera, 1302 ... Case, 1304 ... Light receiving unit, 1306 ... Shutter button, 1308 ... Memory, 1310 ... Display, 1312 ... Video signal output terminal, 1314 ... Input / output terminal, 1430 ... TV monitor, 1440 ... Personal computer

Claims (10)

It is a rectifier circuit that can switch whether it functions as a full-wave rectifier circuit that outputs the input signal by full-wave rectification or as a half-wave rectifier circuit that outputs the input signal by half-wave rectification by a control signal. hand,
A comparator that compares the input signal with the threshold voltage,
An inverting amplifier circuit to which the input signal is input and
A first selection circuit that selects and outputs either the output signal of the inverting amplifier circuit or the first reference voltage based on the control signal, and
A rectifier circuit including a second selection circuit that selects and outputs one of the input signal and the output signal of the first selection circuit based on the output signal of the comparator . A rectifier circuit that can switch between functioning as a full-wave rectifier circuit that outputs the input signal by full-wave rectification or as a half-wave rectifier circuit that outputs the input signal by half-wave rectification by a control signal .
A comparison test circuit that determines whether the voltage obtained by integrating the output signal of the rectifier circuit is higher or lower than the second reference voltage.
A drive circuit including a drive signal generation circuit that generates a drive signal whose amplitude is adjusted based on a determination result of the comparison determination circuit . The rectifier circuit
A comparator that compares the input signal with the threshold voltage,
An inverting amplifier circuit to which the input signal is input and
A first selection circuit that selects and outputs either the output signal of the inverting amplifier circuit or the first reference voltage based on the control signal, and
The drive according to claim 2, further comprising a second selection circuit that selects and outputs either the input signal or the output signal of the first selection circuit based on the output signal of the comparator. circuit. The drive circuit according to claim 2 or 3, wherein the second reference voltage is lower when the rectifier circuit functions as a half-wave rectifier circuit than when the rectifier circuit functions as a full-wave rectifier circuit. Includes a reference voltage circuit with a first resistor
When the rectifier circuit functions as a half-wave rectifier circuit, the current flowing through the first resistor is smaller than when the rectifier circuit functions as a full-wave rectifier circuit.
The drive circuit according to claim 4, wherein the second reference voltage is a voltage at one end of the first resistor. According to any one of claims 2 to 5, the gain of the comparison determination circuit is smaller when the rectifier circuit functions as a half-wave rectifier circuit than when the rectifier circuit functions as a full-wave rectifier circuit. The drive circuit described. Any one of claims 2 to 5, wherein the cutoff frequency of the comparison determination circuit is lower when the rectifier circuit functions as a half-wave rectifier circuit than when the rectifier circuit functions as a full-wave rectifier circuit. The drive circuit described in the section. The drive circuit according to any one of claims 2 to 7.
The physical quantity detection element driven by the drive signal and
A physical quantity detecting device including a detection circuit that generates a physical quantity signal based on an output signal of the physical quantity detecting element. An electronic device including the physical quantity detecting device according to claim 8. A moving body including the physical quantity detecting device according to claim 8.
How to make.

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