JP2016189515A - Circuit device, electronic equipment, and mobile body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit device capable of achieving low power consumption and high accuracy when receiving a detection signal from a physical quantity transducer and converting an input signal from a detection circuit from analog to digital, and electronic equipment and a mobile body.SOLUTION: A circuit device 20 includes a detection circuit 60 which detects a detection signal from a physical quantity transducer 12, and an A/D conversion unit 100 which converts an input signal SA1 from the detection circuit 60 from analog to digital. The A/D conversion unit 100 includes a first A/D conversion circuit 102, and a second A/D conversion circuit 104 for which at least one of an A/D conversion system, a sampling frequency, a resolution, and an input dynamic range is different from the first A/D conversion circuit 102. In a first mode, the first A/D conversion circuit 102 converts the input signal SA1 from analog to digital. In a second mode, the second A/D conversion circuit 104 converts the input signal SA1 from analog to digital.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a circuit device, an electronic device, a moving object, and the like.

  In recent years, motion sensors such as gyro sensors and acceleration sensors have attracted attention. By using such a motion sensor, for example, camera shake correction or intuitive operation input in a game machine can be realized. As a prior art of an apparatus that receives a detection signal from such a physical quantity transducer (sensor element) and performs A / D conversion processing and filter processing, there is a technology disclosed in Patent Document 1, for example. In Patent Document 1, the detection signal from the physical quantity transducer is amplified and synchronously detected, and the synchronously detected signal is A / D converted.

JP 2014-185937 A

  In Patent Document 1 of the prior art, there is one type of A / D conversion circuit that performs A / D conversion on a signal obtained by synchronous detection of a detection signal from a physical quantity transducer. However, it has been difficult to achieve both low power consumption of the A / D conversion circuit and high accuracy of A / D conversion.

  For example, delta-sigma modulation type A / D conversion circuits, successive approximation type A / D conversion circuits, and the like are known as A / D conversion circuits having different A / D conversion methods. When a delta-sigma modulation type A / D conversion circuit is used, high-resolution A / D conversion values can be obtained, while low consumption due to the necessity of an amplifier according to the order and high operating frequency. Electricity is difficult. On the other hand, when the successive approximation A / D converter circuit is used, the power consumption is relatively low, but the resolution is generally lower than that of the delta-sigma modulation A / D converter circuit.

  According to some embodiments of the present invention, a circuit device, an electronic apparatus, and a mobile body that can realize low power consumption and high accuracy when receiving a detection signal from a physical quantity transducer and performing A / D conversion processing. Etc. can be provided.

  One aspect of the present invention includes a detection circuit that performs detection processing of a detection signal from a physical quantity transducer, and an A / D conversion unit that performs A / D conversion on an input signal from the detection circuit. The conversion unit includes a first A / D conversion circuit, and a second A / D conversion that is different from the first A / D conversion circuit in at least one of an A / D conversion method, a sampling frequency, a resolution, and an input dynamic range. The first A / D converter circuit A / D converts the input signal in the first mode, and the second A / D converter circuit converts the input signal in the second mode. The present invention relates to a circuit device for A / D converting an input signal.

  According to one aspect of the present invention, a first A / D conversion circuit and a second A / D conversion circuit that are different in at least one of an A / D conversion method, a sampling frequency, a resolution, and an input dynamic range are provided. In the first mode, A / D conversion is performed by the first A / D conversion circuit, and in the second mode, A / D conversion is performed by the second A / D conversion circuit. Since at least one of the A / D conversion method, sampling frequency, resolution, and input dynamic range is different, the power consumption and A / D conversion accuracy of the first A / D conversion circuit and the second A / D conversion circuit are improved. Different. Accordingly, it is possible to provide a circuit device capable of realizing low power consumption and high accuracy when A / D conversion processing is performed by receiving a detection signal from a physical quantity transducer. For example, it is possible to provide a circuit device capable of realizing low power consumption and high accuracy by using an appropriate A / D conversion circuit according to the use of a signal after A / D conversion.

  In the aspect of the invention, the A / D conversion unit may be provided between an input node of the A / D conversion unit and an input node of the first A / D conversion circuit, and the first mode The first switch element that is turned on in the first switch element, the input node of the A / D converter and the input node of the second A / D converter circuit, and turned on in the second mode. 2 switch elements.

  Thus, by providing the first switch element and the second switch element, the first switch element is turned on in the first mode, and the second switch element is turned on in the second mode. The first A / D conversion circuit and the second A / D conversion circuit can be switched, and switching between high resolution A / D conversion and low power consumption A / D conversion can be realized.

  In one embodiment of the present invention, the second A / D converter circuit is an A / D converter circuit that consumes less power than the first A / D converter circuit, and the second mode is a low-power mode. In the first mode, a signal from the detection circuit is input to the first A / D conversion circuit as the input signal, and in the second mode, a signal from the detection circuit is used. May be input to the second A / D conversion circuit as the input signal.

  As described above, the second A / D conversion circuit that consumes less power than the first A / D conversion circuit is provided, and the second A / D conversion circuit performs A / D conversion in the second mode. Thus, A / D conversion with low power consumption can be realized by switching to the second mode.

  In the aspect of the invention, the A / D converter may include a first input signal that is a signal from the detection circuit and a second signal that is a signal from a second physical quantity transducer as the input signal. In the first mode, the first input signal is input to the first A / D converter circuit, and the second input signal is input to the second A / D converter. In the second mode, the first input signal and the second input signal may be input to the second A / D conversion circuit in a time division manner.

  As described above, in the second mode, the first input signal and the second input signal are input to the second A / D conversion circuit in a time division manner, whereby the first input signal and the second input signal are changed. A / D conversion can be performed in time division. By using time division, the number of second A / D conversion circuits provided for the second mode can be made one, and an increase in circuit scale can be suppressed in realizing mode switching.

  In the aspect of the invention, the first physical quantity transducer may be an angular velocity sensor element, and the second physical quantity transducer may be a temperature sensor or an acceleration sensor element.

  According to this configuration, in the first mode, the first input signal based on the signal from the angular velocity sensor element is input to the first A / D conversion circuit, and the first input signal based on the signal from the temperature sensor or the acceleration sensor element is input. 2 input signals are input to the second A / D conversion circuit. In the second mode, the first input signal and the second input signal are input to the second A / D conversion circuit in a time division manner. Accordingly, it is possible to detect the angular velocity with high resolution by setting the first mode, and it is possible to detect the angular velocity and temperature or acceleration with low power consumption by setting the second mode. It becomes possible.

  In one embodiment of the present invention, the first A / D conversion circuit is a delta-sigma modulation type A / D conversion circuit, and the second A / D conversion circuit is a successive approximation type A / D conversion circuit. It may be a conversion circuit.

  In general, a delta-sigma modulation type A / D conversion circuit has higher resolution than a successive approximation type A / D conversion circuit, and the successive approximation type A / D conversion circuit is a delta sigma modulation type A / D conversion circuit. Low power consumption compared to the conversion circuit. That is, according to one embodiment of the present invention, A / D conversion with higher resolution can be performed in the first mode than in the second mode, and power consumption is lower in the second mode than in the first mode. A / D conversion can be performed.

  According to another aspect of the present invention, the processing unit includes a processing unit that digitally processes the output of the A / D conversion unit, and the processing unit in the first mode is an A / D of the first A / D conversion circuit. The conversion value may be digitally processed by the first processing method, and in the second mode, the A / D conversion value of the second A / D conversion circuit may be digitally processed by the second processing method.

  In this way, by switching the digital processing method between the first mode and the second mode, digital processing with a processing method corresponding to the A / D conversion circuit selected in each mode can be performed.

  In the aspect of the invention, the first processing method and the second processing method may be different in at least one of digital filter processing and digital correction processing.

  For example, when the resolution of the A / D conversion circuit is different, the correction value of the digital correction process changes. Alternatively, if the sampling frequency of the A / D conversion circuit is different, the frequency characteristic of the digital filter processing changes according to the sampling frequency when the filter coefficient is not changed. In this regard, according to one aspect of the present invention, since at least one of the digital filter processing and the digital correction processing is different between the first mode and the second mode, the digital correction processing with an appropriate correction value according to the mode or Digital filter processing with a filter coefficient corresponding to the mode can be performed.

  In one aspect of the present invention, the first mode and the second mode include an interface unit and a register unit, and the first mode and the second mode are based on a mode setting value set in the register unit via the interface unit. It may be switched.

  In this way, the external processing device can switch between the first mode and the second mode by setting the mode setting value in the register unit via the interface unit. For example, it becomes possible for an external processing device to switch between high resolution A / D conversion and low power consumption A / D conversion according to the application, environment, situation, and the like.

  In one embodiment of the present invention, in the first mode, switching from the first mode to the second mode is performed based on a detection value based on an A / D conversion value of the first A / D conversion circuit. A control unit may be included.

  In one embodiment of the present invention, in the second mode, switching from the second mode to the first mode is performed based on a detection value based on an A / D conversion value of the second A / D conversion circuit. A control unit may be included.

  According to these one aspect | mode of this invention, a switching control part can switch a 1st mode and a 2nd mode by switching a mode with the detection value based on an A / D conversion value. Accordingly, the circuit device can switch between high resolution A / D conversion and low power consumption A / D conversion according to, for example, the situation.

  In one embodiment of the present invention, the first A / D conversion circuit is an A / D conversion circuit that consumes more power than the second A / D conversion circuit. In the second mode, The first A / D conversion circuit may be set to a low power consumption state or an operation disabled state.

  The first A / D conversion circuit having higher power consumption than the second A / D conversion circuit is set in the low power consumption state or the operation disabled state in the second mode, so that Power consumption can be suppressed and A / D conversion with low power consumption can be performed in the second mode.

  Another aspect of the invention relates to an electronic device including the circuit device described in any of the above.

  Another aspect of the present invention relates to a moving body including the circuit device described in any of the above.

1 is a first configuration example of a circuit device according to an embodiment. The operation | movement timing chart of the circuit apparatus of a 1st structural example. 2 shows a second configuration example of a circuit device according to the present embodiment. The operation | movement timing chart of the circuit apparatus of a 2nd structural example. The 3rd structural example of the circuit apparatus of this embodiment. The operation | movement timing chart of the circuit apparatus of the 3rd structural example. 4 shows a fourth configuration example of a circuit device according to the present embodiment. The operation | movement timing chart of the circuit apparatus of the 4th structural example. The detailed structural example of a process part. The 5th structural example of the circuit apparatus of this embodiment. 6 is a sixth configuration example of a circuit device according to the present embodiment. Explanatory drawing of operation | movement of the circuit apparatus of the 6th structural example. 7 shows a seventh configuration example of the circuit device according to the present embodiment. The operation | movement timing chart of the circuit apparatus of the 7th structural example. 1 is a configuration example of a circuit device, an electronic device, and a gyro sensor (physical quantity detection device) of the present embodiment. 3 shows detailed configuration examples of a drive circuit and a detection circuit. FIGS. 17A to 17D are examples of a moving body and an electronic device in which the circuit device of this embodiment is incorporated.

  Hereinafter, preferred embodiments of the present invention will be described in detail. The present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in the present embodiment are indispensable as means for solving the present invention. Not necessarily.

1. First Configuration Example of Circuit Device FIG. 1 shows a first configuration example of a circuit device according to this embodiment. The circuit device 20 includes a detection circuit 60 that detects the detection signal SD from the physical quantity transducer 12, and an A / D conversion unit 100 that A / D converts the input signal SA1 from the detection circuit 60. Note that the A / D conversion unit 100 only needs to be provided at the subsequent stage of the detection circuit 60, and the output signal of the detection circuit 60 does not need to be directly input to the A / D conversion unit 100. The circuit device 20 includes a processing unit 110 that digitally processes the output of the A / D conversion unit 100, and a switching control unit 120 that switches the A / D conversion mode.

  The A / D conversion unit 100 includes a first A / D conversion circuit 102 and a second A / D conversion circuit 104. The second A / D conversion circuit 104 is different from the first A / D conversion circuit 102 in at least one of an A / D conversion method, a sampling rate, a resolution, and an input dynamic range. In the first mode, the first A / D conversion circuit 102 A / D converts the input signal SA1 of the A / D conversion unit 100, and in the second mode, the second A / D conversion circuit 104 is converted. A / D converts the input signal SA1 of the A / D converter 100.

  Specifically, the physical quantity transducer 12 is an element that detects various physical quantities (for example, angular velocity, angular acceleration, acceleration, temperature, pressure, magnetism, or physical quantities equivalent to these) and converts them into electrical signals.

  The input signal SA1 of the A / D conversion unit 100 is an output signal of the detection circuit 60 in the configuration example of FIG. However, the present invention is not limited to this. For example, a circuit may be further provided between the detection circuit 60 and the A / D conversion unit 100, and the output signal of the circuit may be used as the input signal SA1 of the A / D conversion unit 100. .

  The first A / D conversion circuit 102 and the second A / D conversion circuit 104 may be different in only one of the A / D conversion method, the sampling frequency, the resolution, and the input dynamic range, or different in plural. Or all may be different.

  As the A / D conversion method, for example, a delta sigma modulation type, a successive approximation type, a double integration type, a flash type, a pipeline type, and the like can be assumed. The sampling frequency is a frequency at which the A / D conversion circuit samples the input signal. Even if the frequency at which the A / D conversion circuit outputs the A / D conversion value is the same, the sampling frequency may be different. For example, in the successive approximation type, the sampling frequency and the output frequency are usually the same, and in the delta sigma modulation type, the sampling frequency is higher than the output frequency. The resolution is the magnitude of the physical quantity corresponding to 1 LSB of the A / D conversion value or the magnitude of the input signal corresponding to 1 LSB of the A / D conversion value. Alternatively, the number of bits of the A / D conversion value is called resolution. The input dynamic range is a range of an input signal to be A / D converted.

  Switching between the first mode and the second mode is performed by the switching control unit 120. That is, when the switching control unit 120 outputs the mode control signal MDS for instructing the first mode, the A / D conversion unit 100 performs A / D conversion on the input signal by the first A / D conversion circuit 102, When the switching control unit 120 outputs the mode control signal MDS for instructing the second mode, the A / D conversion unit 100 performs A / D conversion on the input signal by the second A / D conversion circuit 104.

  As described above, the first and second A / D conversion circuits 102 and 104 are provided. In the first and second modes, the first and second A / D conversion circuits 102 and 104 are respectively By performing D conversion, both low power consumption and high accuracy can be achieved. That is, the first and second A / D conversion circuits 102 and 104 are different in at least one of the A / D conversion method, the sampling rate, the resolution, and the input dynamic range, so that the power consumption and the A / D conversion accuracy ( For example, resolution, linearity, S / N, time resolution, etc.) are different. By switching these A / D conversion circuits, it is possible to switch between high-precision A / D conversion and low-power consumption A / D conversion as necessary.

  For example, in a gyro sensor (physical quantity transducer 12 is an angular velocity sensor element), the angular velocity is integrated to obtain an angle. Therefore, the angular velocity error is integrated to increase the angular error. Therefore, it is desirable to obtain a highly accurate angular velocity using a delta-sigma modulation type A / D conversion circuit or the like. However, depending on the application, environment, situation, etc., it may be desirable to suppress power consumption without the need to measure with high accuracy (for example, the time when the angular velocity is close to zero, the time when the change in angular velocity is small) Etc.). In this embodiment, the power consumption can be reduced by switching to the second mode in such a case, and both high-accuracy measurement and low power consumption can be achieved according to the application, environment, situation, and the like.

  In this embodiment, the A / D converter 100 includes the first switch element SW1 provided between the input node NA1 of the A / D converter 100 and the input node NB1 of the first A / D converter circuit 102. And a second switch element SW2 provided between the input node NA1 of the A / D converter 100 and the input node NB2 of the second A / D converter circuit 104.

  Then, the first switch element SW1 is turned on in the first mode, and the second switch element SW2 is turned on in the second mode.

  Specifically, the first and second switch elements SW1 and SW2 are constituted by, for example, a transfer gate (a P-type transistor and an N-type transistor connected in parallel), a P-type transistor, an N-type transistor, or the like. . Further, the nodes NA1, NB1, and NB2 may be differential input nodes. In this case, a switch element is provided for each of the first node and the second node that constitute the differential input node.

  FIG. 2 shows an operation timing chart of the circuit device 20 of FIG. In the chart of the switch elements SW1 and SW2, the high level indicates that the switch element is on and the low level indicates that the switch element is off. As shown in FIG. 2, when the mode control signal MDS is at a low level (first logic level in a broad sense), the first mode is set, the first switch element SW1 is turned on, and the second switch element SW2 is turned off. On the other hand, when the mode control signal MDS is at a high level (second logic level in a broad sense), the second mode is set, the first switch element SW1 is turned off, and the second switch element SW2 is intermittently turned on. Turns on (intermittently). For example, when a successive approximation type A / D conversion circuit is employed as the second A / D conversion circuit 104, it can be intermittently turned on. For example, one A / D conversion is performed in one ON period (one A / D conversion value is output). Note that the second switch element SW2 may be continuously turned on.

  During the period when the switch element SW2 is OFF in the first mode, the second A / D conversion circuit 104 is set to an operation disabled state (operation stop state) or a low power consumption state. In a period in which the switch element SW1 is off in the second mode, the first A / D conversion circuit 102 is set to an operation disabled state or a low power consumption state. The operation disabled state is a state in which the internal operation of the A / D conversion circuit is stopped (for example, the operation of the switch element, the amplifier circuit, the logic circuit, etc. is stopped). The low power consumption state is a state in which the power consumption of the internal circuit of the A / D conversion circuit is reduced (for example, the bias current of the amplifier circuit is stopped or reduced).

  As described above, the first and second switch elements SW1 and SW2 are provided, and the first and second switch elements SW1 and SW2 are turned on in the first and second modes, respectively. The A / D conversion circuit 102 and the second A / D conversion circuit 104 can be switched, and switching between the high resolution mode and the low power consumption mode can be realized.

  In the present embodiment, the second A / D conversion circuit 104 is an A / D conversion circuit that consumes less power than the first A / D conversion circuit 102. The second mode is a low power consumption mode. In the first mode, the signal from the detection circuit 60 is input to the first A / D conversion circuit 102 as the input signal SA1, and in the second mode, the signal from the detection circuit 60 is the second input signal SA1. Input to the A / D conversion circuit 104.

  Examples of A / D conversion circuits with different power consumption include A / D conversion circuits with different A / D conversion methods, A / D conversion circuits with the same A / D conversion method and different sampling frequencies, and delta-sigma modulation type A Even in the same A / D conversion system such as the order of the / D conversion circuit, A / D conversion circuits having different internal configurations are assumed.

  As described above, by providing the second A / D conversion circuit 104 that consumes less power than the first A / D conversion circuit 102, A / D conversion with low power consumption can be achieved by switching to the second mode. Can be realized.

  In the present embodiment, the switch element SW2 is intermittently turned off in the second mode as shown in FIG. 2, but the second A / D conversion circuit 104 is operated during the period when the switch element SW2 is turned off. Set to disabled or low power consumption. Thereby, it is possible to further reduce the power consumption of the second mode compared to the case where the second A / D conversion circuit 104 continuously performs A / D conversion in the second mode.

  In this embodiment, the first A / D conversion circuit 102 is a delta-sigma modulation type A / D conversion circuit, and the second A / D conversion circuit 104 is a successive approximation type A / D conversion circuit. It is.

  Specifically, a delta-sigma modulation type A / D conversion circuit includes a sampling circuit that samples an input signal, a differencer that outputs a difference between an output of the sampling circuit and an output of the quantizer, and an output of the differencer , A quantizer that quantizes the output of the integrator, and a D / A conversion circuit that D / A converts the output of the quantizer and feeds back to the difference unit. This is a configuration for one loop, and in the case of the second or higher order, there are loops corresponding to the order. An A / D conversion value is output by oversampling at a frequency higher than a desired sampling frequency (output frequency of the A / D conversion value) and down-sampling the output of the quantizer with a decimation filter.

  The successive approximation type A / D conversion circuit includes a sampling circuit that samples an input signal, a comparison circuit that compares an output of the sampling circuit and an output of the D / A conversion circuit, and a register that updates a register value with the output of the comparison circuit And a D / A conversion circuit that D / A converts the register value and outputs it to the comparison circuit. The sampling circuit, the comparison circuit, and the D / A conversion circuit may be configured integrally (for example, a switched capacitor circuit). For one sampling, the comparison by the comparison circuit and the update of the register value based on the result are repeated bit by bit from the MSB side of the register value, and an A / D conversion value is output.

  A delta-sigma modulation type A / D conversion circuit easily achieves high resolution by oversampling, but has a large number of amplifier circuits (for example, an amplifier, an amplifier circuit included in the D / A conversion circuit. Secondary) In the above case, the number of amplifiers is, for example, the order multiple) and the sampling frequency is high, so it is difficult to reduce power consumption. The successive approximation type A / D converter circuit has a small number of amplifier circuits (for example, an amplifier circuit included in the comparison circuit) and a low sampling frequency, so it is easy to reduce power consumption. Therefore, it is difficult to increase the resolution. As an example, a delta-sigma modulation type A / D conversion circuit has a resolution of 12 to 24 bits and a sampling frequency of 100 to 10 MHz. The successive approximation A / D converter circuit has a resolution of 8 to 16 bits and a sampling frequency of 10 k to 1 MHz.

  As described above, the first A / D conversion circuit 102 is a delta-sigma modulation type A / D conversion circuit, and the second A / D conversion circuit 104 is a successive approximation type A / D conversion circuit. In the first mode, A / D conversion with higher resolution than in the second mode can be performed, and in the second mode, A / D conversion with lower power consumption than in the first mode can be performed. .

2. Second Configuration Example of Circuit Device FIG. 3 shows a second configuration example of the circuit device according to the present embodiment. The circuit device 20 includes a temperature sensor 18, a detection circuit 60, an A / D conversion unit 100, a processing unit 110, and a switching control unit 120. In addition, the same code | symbol is attached | subjected about the component same as the component already demonstrated, and description is abbreviate | omitted suitably.

  The A / D conversion unit 100 includes first and second A / D conversion circuits 102 and 104, first and second switch elements SW1 and SW2, and a second input node NA2 of the A / D conversion unit 100. And a third switch element SW3 provided between the input node NB2 of the second A / D conversion circuit 104.

  The A / D converter 100 receives as input signals a first input signal SA1 that is a signal from the detection circuit 60 and a second input signal SA2 that is based on the signal from the second physical quantity transducer. Is done. In the first mode, the first input signal SA 1 is input to the first A / D conversion circuit 102, and the second input signal SA 2 is input to the second A / D conversion circuit 104. In the second mode, the first input signal SA1 and the second input signal SA2 are input to the second A / D conversion circuit 104 in a time division manner.

  FIG. 4 shows an operation timing chart of the circuit device 20 of FIG. In the chart of the switch elements SW1 to SW3, the high level indicates that the switch element is on, and the low level indicates that the switch element is off. As shown in FIG. 4, in the first mode, the first switch element SW1 is turned on, the second switch element SW2 is turned off, and the third switch element SW3 is turned on intermittently. In the second mode, the first switch element SW1 is turned off, and the second switch element SW2 and the third switch element SW3 are turned on in a time division manner. That is, the second and third switch elements SW2 and SW3 constitute a multiplexer that sequentially selects the first and second input signals SA1 and SA2.

  In the second mode, the second A / D conversion circuit 104 maintains the operation on state. Alternatively, if there is a period during which both the first and second switch elements SW1 and SW2 are off, even if the second A / D conversion circuit 104 is set to an operation disabled state or a low power consumption state during that period. Good.

  As described with reference to FIG. 1, the second A / D conversion circuit 104 is a successive approximation type A / D conversion circuit. Since the successive approximation type A / D conversion circuit does not loop past A / D conversion values, the time until the A / D conversion value is obtained from the input of the signal is compared with the delta-sigma modulation type A / D conversion circuit. Short and suitable for time-sharing operations.

  As described above, by inputting the first input signal SA1 and the second input signal SA2 to the second A / D conversion circuit 104 in a time division manner in the second mode, the first input signal SA1 and the second input signal SA2 The two input signals SA2 can be A / D converted in a time division manner. By using time division, even if there are a plurality of inputs, it is only necessary to provide one second A / D conversion circuit 104, and the first mode and the second mode can be reduced while minimizing the addition of circuits. Mode switching can be realized.

  In the present embodiment, the first physical quantity transducer is the angular velocity sensor element 14, and the second physical quantity transducer is the temperature sensor 18.

  The angular velocity sensor element 14 is an element that detects angular velocity, and is, for example, a piezoelectric vibrating piece (for example, a double T-shaped vibrating piece to be described later), a capacitance detecting type vibrating piece, or the like. The temperature sensor 18 is an element or a circuit that generates at least a temperature-dependent signal. Specifically, a temperature-dependent signal and a temperature-independent reference signal are generated, the signals are compared, and a signal obtained by the comparison is output as temperature information. The temperature sensor 18 can be realized by, for example, a band gap circuit and a comparison circuit.

  The temperature information obtained by the temperature sensor 18 is used to correct the zero point of the angular velocity and the temperature dependence of the gain. The temperature information only needs to have a resolution necessary for correction, and the output of the temperature sensor 18 is A / D converted by the second successive approximation A / D conversion circuit 104 regardless of the mode. On the other hand, the output of the angular velocity sensor element 14 is A / D converted by the first A / D conversion circuit 102 of the delta-sigma modulation type when the first mode is selected when high resolution is required, and the output is low. If it is good, the second mode is selected and A / D conversion is performed by the second successive approximation type A / D conversion circuit 104.

  For example, as shown in FIG. 16, the detection circuit 60 that processes the detection signal from the angular velocity sensor element 14 includes an amplification circuit that amplifies the detection signal, a synchronous detection circuit that synchronously detects the signal from the amplification circuit, and a synchronous detection circuit. A filter unit 90 for low-pass filtering the signal from

  As shown in FIG. 5, the second physical quantity transducer may be an acceleration sensor element 16. In the first mode, the first A / D conversion circuit 102 performs A / D conversion on the output of the angular velocity sensor element 14, so that a highly accurate angular velocity can be obtained. On the other hand, in the second mode, the second A / D conversion circuit 104 A / D converts the output of the angular velocity sensor element 14 and the output of the acceleration sensor element 16 in a time division manner, and the first A / D conversion circuit 102. Since the operation is disabled, A / D conversion can be performed with low power consumption.

3. Third Configuration Example of Circuit Device FIG. 3 shows a third configuration example of the circuit device according to the present embodiment. The circuit device 20 includes a temperature sensor 18, detection circuits 60 and 62, an A / D conversion unit 100, a processing unit 110, and a switching control unit 120. In addition, the same code | symbol is attached | subjected about the component same as the component already demonstrated, and description is abbreviate | omitted suitably.

  The acceleration sensor element 16 is an element that detects acceleration, and is, for example, an electrostatic capacitance detection element, a piezoresistive element, a thermal detection element, or the like. The detection circuit 62 that detects the detection signal from the acceleration sensor element 16 includes, for example, an amplification circuit that amplifies the detection signal. Further, a synchronous detection circuit that synchronously detects a signal from the amplifier circuit may be included.

  The A / D conversion unit 100 includes first and second A / D conversion circuits 102 and 104, a first input node NC1 of the A / D conversion unit 100, and an input node of the first A / D conversion circuit 102. Between the first switch element SWC1 provided between ND1 and the first to third input nodes NC1 to NC3 of the A / D converter 100 and the input node ND2 of the second A / D converter circuit 104 2 to 4 switch elements SWC2 to SWC4 provided in the circuit board.

  The A / D converter 100 receives as input signals a first input signal SC1 that is a signal from the detection circuit 60, a second input signal SC2 that is a signal from the detection circuit 62, and the temperature sensor 18. The third input signal SC3, which is a signal of In the first mode, the first input signal SC 1 is input to the first A / D conversion circuit 102, and the second and third input signals SC 2 and SC 3 are input to the second A / D conversion circuit 104. Entered. In the second mode, the first to third input signals SC1 to SC3 are input to the second A / D conversion circuit 104 in a time division manner.

  FIG. 6 shows an operation timing chart of the circuit device 20 of FIG. In the chart of the switch elements SWC1 to SWC4, the high level indicates that the switch element is on, and the low level indicates that the switch element is off. As shown in FIG. 6, in the first mode, the first switch element SWC1 is turned on, the second switch element SWC2 is turned off, and the third and fourth switch elements SWC3 and SWC4 are time-shared. Turn on. At this time, the third switch element SWC3 is turned on, the fourth switch element SWC4 is turned on, and the third and fourth switch elements SWC3 and SWC4 are both turned off in a time division manner. In the second mode, the first switch element SWC1 is turned off, and the second to fourth switch elements SWC2 to SWC4 are turned on in a time division manner. That is, the second to fourth switch elements SWC2 to SWC4 form a multiplexer that sequentially selects the first to third input signals SC1 to SC3.

  In the first mode, the second A / D conversion circuit 104 is set to an operation disabled state or a low power consumption state during a period in which both the third and fourth switch elements SWC3 and SWC4 are off. . In the second mode, the second A / D conversion circuit 104 maintains the operation on state. Alternatively, when there is a period in which all of the second to fourth switch elements SWC2 to SWC4 are off, even if the second A / D conversion circuit 104 is set to the operation disabled state or the low power consumption state during that period. Good.

  As described above, even when a combo sensor of a single axis gyro sensor and an acceleration sensor is configured, the second A / D conversion circuit 104 A / D converts a plurality of signals in a time division manner in the second mode. Therefore, low power consumption can be achieved. Further, since a plurality of signals can be A / D converted by one successive approximation type A / D conversion circuit, the circuit scale can be suppressed even if the number of signals increases.

4). Fourth Configuration Example of Circuit Device FIG. 7 shows a fourth configuration example of the circuit device according to the present embodiment. The circuit device 20 includes a temperature sensor 18, detection circuits 65, 67, 69, an A / D conversion unit 100, a processing unit 110, and a switching control unit 120. In addition, the same code | symbol is attached | subjected about the component same as the component already demonstrated, and description is abbreviate | omitted suitably.

  The angular velocity sensor elements 15, 17, and 19 are sensor elements that detect angular velocities of three orthogonal axes (X axis, Y axis, and Z axis). The detection circuits 65, 67, and 69 detect the detection signals from the angular velocity sensor elements 15, 17, and 19, respectively.

  The A / D converter 100 includes delta-sigma modulation type A / D conversion circuits 105, 107, and 109 (first, third, and fourth A / D conversion circuits in a broad sense) and a successive approximation type A / D conversion circuit 103 (second A / D conversion circuit in a broad sense), first to third input nodes NE1 to NE3 of the A / D conversion unit 100, and a delta-sigma modulation type A / D conversion circuit The first to third switch elements SWE1 to SWE3 provided between the input nodes NF1 to NF3 of 105, 107, and 109, and the first to fourth input nodes NE1 to NE4 of the A / D conversion unit 100, sequentially. 4th to 7th switch elements SWE4 to SWE7 provided between the comparison type A / D conversion circuit 103 and the input node NF4.

  The A / D conversion unit 100 has, as input signals, first to third input signals SE1 to SE3 that are signals from the detection circuits 65, 67, and 69, and a fourth input that is a signal from the temperature sensor 18. Signal SE4 is input. In the first mode, the first to third input signals SE1 to SE3 are input to the delta-sigma modulation type A / D conversion circuits 105, 107, and 109, and the fourth input signal SE4 is a successive approximation type. Input to the A / D conversion circuit 103. In the second mode, the first to fourth input signals SE <b> 1 to SE <b> 4 are input to the successive approximation A / D conversion circuit 103 in a time division manner.

  FIG. 8 shows an operation timing chart of the circuit device 20 of FIG. In the charts of the switch elements SWE1 to SWE7, the high level indicates that the switch element is on, and the low level indicates that the switch element is off. As shown in FIG. 8, in the first mode, the first to third switch elements SWE1 to SWE3 are turned on, the fourth to sixth switch elements SWE4 to SWE6 are turned off, and the seventh switch element is turned on. SWE7 is intermittently turned on. In the second mode, the first to third switch elements SWE1 to SWE3 are turned off, and the fourth to seventh switch elements SWE4 to SWE7 are turned on in a time division manner. That is, the fourth to seventh switch elements SWE4 to SWE7 form a multiplexer that sequentially selects the first to fourth input signals SE1 to SE4.

  In the first mode, the second A / D conversion circuit 104 is set to an operation disabled state or a low power consumption state during a period in which the seventh switch element SWE7 is off. In the second mode, the second A / D conversion circuit 104 maintains the operation on state. Alternatively, if there is a period in which all of the fourth to seventh switch elements SWE4 to SWE7 are off, even if the second A / D conversion circuit 104 is set to the operation disabled state or the low power consumption state during that period. Good.

  As described above, even when the combo sensor of the three-axis gyro sensor and the acceleration sensor is configured, the second A / D conversion circuit 104 A / D converts a plurality of signals in a time division manner in the second mode. Therefore, low power consumption can be achieved. Further, since a plurality of signals can be A / D converted by one successive approximation type A / D conversion circuit, the circuit scale can be suppressed even if the number of signals increases.

5. Processing Unit Details of the processing unit 110 will be described below. The processing unit 110 digitally processes the A / D conversion value of the first A / D conversion circuit 102 by the first processing method in the first mode, and performs the second A / D conversion in the second mode. The A / D conversion value of the circuit 104 is digitally processed by the second processing method.

  That is, when the switching control unit 120 outputs the mode control signal MDS for instructing the first mode, the processing unit 110 selects the first processing method, and the switching control unit 120 instructs the first mode. When the mode control signal MDS is output, the processing unit 110 selects the second processing method.

  The processing unit 110 is, for example, a DSP (Digital Signal Processor), and is realized by a logic circuit such as a gate array. The digital processing performed by the processing unit 110 is, for example, A / D conversion value filter processing, correction processing, conversion processing, and the like. As the filter processing, for example, low-pass filter processing, band-pass filter processing, or the like is assumed. As the correction processing, for example, offset correction, gain correction, temperature characteristic correction, and the like are assumed. As the conversion process, for example, a process for converting an A / D conversion value into a physical quantity, a process for converting a characteristic of an A / D conversion value with respect to a physical quantity, a sampling frequency conversion, and the like are assumed. The first and second processing methods differ, for example, in the contents and parameters of the digital processing described above. For example, filter processing and correction processing may be performed in the first processing method, correction processing and conversion processing may be performed in the second processing method, or filter processing and correction may be performed in both the first and second processing methods. Processes may be performed and the parameters of each process may be different.

  FIG. 9 shows a detailed configuration example of the processing unit 110. Hereinafter, a case where the physical quantity transducer is an angular velocity sensor element (gyro sensor) will be described as an example.

  FIG. 9 is a configuration example of the processing unit 110 when the digital filter processing and the digital correction processing are different between the first processing method and the second processing method. The configuration of the processing unit 110 is not limited to that in FIG. 9, and it is sufficient that at least one of the digital filter processing and the digital correction processing is different between the first processing method and the second processing method.

  The processing unit 110 includes a selector 111, a zero point correction unit 112, a gain correction unit 113, a digital filter 114, a correction coefficient selection unit 115, and a filter coefficient selection unit 116.

  The selector 111 selects the A / D conversion value from the first A / D conversion circuit 102 in the first mode, and the A / D conversion value from the second A / D conversion circuit 104 in the second mode. Select.

  The correction coefficient selection unit 115 selects the first zero point correction value and the first gain correction value in the first mode, and selects the second zero point correction value and the second gain correction value in the second mode. select. For example, the circuit device 20 includes a storage unit (not shown) that stores the first and second zero point correction values and the first and second gain correction values, and the correction coefficient selection unit 115 stores the storage unit according to the mode. Read correction value from. The first and second zero point correction values and the first and second gain correction values each have temperature characteristics, and the correction coefficient selection unit 115 performs correction according to the temperature measured by the temperature sensor. Select a value.

  The zero point correction unit 112 performs zero point correction on the A / D conversion value selected by the selector 111. That is, the zero point correction value selected by the correction coefficient selection unit 115 is added to the A / D conversion value (or subtracted from the A / D conversion value).

  The gain correction unit 113 performs gain correction on the A / D conversion value selected by the selector 111. That is, the A / D conversion value is multiplied by the gain correction value selected by the correction coefficient selection unit 115.

  The filter coefficient selection unit 116 selects the first filter coefficient in the first mode, and selects the second filter coefficient in the second mode. For example, the circuit device 20 includes a storage unit (not shown) that stores the first and second filter coefficients, and the filter coefficient selection unit 116 reads the filter coefficients from the storage unit according to the mode.

  The digital filter 114 performs filter processing on the output of the gain correction unit 113. That is, the filter processing characteristics are set by the filter coefficient selected by the filter coefficient selection unit 116, and the filter processing is performed on the output of the gain correction unit 113. The filter coefficient is, for example, a coefficient included in the transfer function of the digital filter 114, and the frequency characteristic of the transfer function changes by changing the filter coefficient. For example, the digital filter 114 is a low-pass filter, and the ratio between the cutoff frequency and the sampling frequency varies depending on the filter coefficient.

  The first A / D conversion circuit 102 of the delta sigma modulation type and the second A / D conversion circuit 104 of the successive approximation type have different resolutions (number of bits) of the A / D conversion value. The gain correction value is also different. That is, even if the offset and sensitivity are the same on the input side of the A / D converter circuit, the offset / sensitivity is different in the A / D conversion value due to the difference in resolution (for example, 1V full scale is A / D with 10 bits and 12 bits). In the case of D conversion, 1 mV is 1 LSB and 4 LSB, respectively.

  The frequency characteristics of the digital filter 114 are determined based on the sampling frequency. For example, the cut-off frequency of the low-pass filter is defined as a ratio to the sampling frequency, and when the sampling frequency is doubled, the cut-off frequency is doubled (the ratio is not changed).

  In this regard, according to the present embodiment, since digital processing is switched between the first mode and the second mode, digital processing of a processing method corresponding to the A / D conversion circuit selected in each mode can be performed. . That is, even if the resolution changes according to the A / D conversion circuit, zero point correction and gain correction can be performed accordingly. Even if the sampling frequency changes according to the A / D conversion circuit, the ratio between the cutoff frequency and the sampling frequency can be changed accordingly, and an appropriate cutoff frequency can be set (for example, the same cutoff frequency regardless of the mode). Off frequency can be set).

6). Fifth Configuration Example of Circuit Device FIG. 10 shows a fifth configuration example of the circuit device of this embodiment. The circuit device 20 includes a detection circuit 60, an A / D conversion unit 100, a processing unit 110, a switching control unit 120, a register unit 142, and an interface unit 144. In addition, the same code | symbol is attached | subjected about the component same as the component already demonstrated, and description is abbreviate | omitted suitably.

  The first mode and the second mode are switched based on the mode setting value set in the register unit 142 via the interface unit 144.

  Specifically, the interface unit 144 performs communication with a processing device (for example, a CPU or a microcomputer) outside the circuit device 20. The external processing device writes the mode setting value to the register unit 142 via the interface unit 144, and the switching control unit 120 processes the mode control signal MDS of the mode indicated by the mode setting value with the A / D conversion unit 100. Output to the unit 110.

  According to the above configuration, the external processing device can switch between the first mode and the second mode by setting the mode setting value in the register unit 142 via the interface unit 144. That is, the external processing apparatus can switch between high resolution A / D conversion and low power consumption A / D conversion according to the application, environment, situation, and the like.

7. Sixth Configuration Example of Circuit Device FIG. 11 shows a sixth configuration example of the circuit device of this embodiment. The circuit device 20 includes a detection circuit 60, an A / D conversion unit 100, a processing unit 110, and a switching control unit 120. In addition, the same code | symbol is attached | subjected about the component same as the component already demonstrated, and description is abbreviate | omitted suitably.

  In the first mode, the switching control unit 120 switches from the first mode to the second mode based on the detection value based on the A / D conversion value of the first A / D conversion circuit 102. In the second mode, the switching control unit 120 switches from the second mode to the first mode based on the detection value based on the A / D conversion value of the second A / D conversion circuit 104.

  Specifically, in the first mode, the processing unit 110 digitally processes the A / D conversion value of the first A / D conversion circuit 102 to acquire a detection value (physical quantity), and the switching control unit 120 It is determined whether or not to switch from the first mode to the second mode based on the detected value. In the second mode, the processing unit 110 digitally processes the A / D conversion value of the second A / D conversion circuit 104 to acquire a detection value (physical quantity), and the switching control unit 120 is based on the detection value. To determine whether to switch from the second mode to the first mode.

  FIG. 12 shows an operation explanatory diagram of the circuit device of FIG. In FIG. 12, a case where the physical quantity transducer 12 is an angular velocity sensor element (gyro sensor) will be described as an example.

  When the absolute value of the angular velocity (detected value) exceeds the first threshold value TH1 in the second mode, the switching control unit 120 switches from the second mode to the first mode. For example, the second mode is switched to the first mode when the absolute value of the angular velocity exceeds the first threshold value TH1 a plurality of times (twice in the example of FIG. 12) within a predetermined length of time.

  On the other hand, when the absolute value of the angular velocity is smaller than the second threshold value TH2 (TH2 <TH1) in the first mode, the switching control unit 120 switches from the first mode to the second mode. For example, when the absolute value of the angular velocity is continuously smaller than the second threshold value TH2 within the predetermined length period (the absolute value of the angular velocity does not exceed the second threshold value TH2 within the predetermined length period). Switch from the first mode to the second mode.

  As described above, the switching control unit 120 can switch between the first mode and the second mode by switching the mode according to the detection value based on the A / D conversion value. As a result, the circuit device 20 can automatically switch between high resolution A / D conversion and low power consumption A / D conversion according to the situation. For example, when the movement of the device equipped with the gyro sensor is large and the angular velocity is large, the first A / D conversion circuit 102 of the delta-sigma modulation type performs high-precision detection, and the movement of the device equipped with the gyro sensor When the angular velocity is small and low, detection with low power consumption can be performed. By monitoring the angular velocity with low power consumption detection when the motion is small, power consumption can be saved, and when the motion becomes large, the detection can be shifted to high accuracy.

8). Seventh Configuration Example of Circuit Device FIG. 13 shows a seventh configuration example of the circuit device of this embodiment. The circuit device 20 includes a buffer circuit 43, a detection circuit 60, a second A / D conversion circuit 104, and switch elements SW2P and SW2N. In FIG. 13, the first A / D conversion circuit 102, the processing unit 110, and the like are not shown. In addition, the same code | symbol is attached | subjected about the component same as the component already demonstrated, and description is abbreviate | omitted suitably.

  In the following, the case where the physical quantity transducer is the angular velocity sensor element 14 will be described as an example, but the buffer circuit 43 may be provided when the physical quantity transducer is an acceleration sensor element.

  The switch elements SW2P and SW2N correspond to the switch element SW2 in FIG. 3, the switch element SWC2 in FIG. 5, and the switch elements SWE4, SWE5, and SWE6 in FIG. 7 when the output of the detection circuit is differential. That is, it corresponds to a switch element of a multiplexer that switches a plurality of inputs of the second A / D conversion circuit 104 in a time division manner in the second mode.

  The detection circuit 60 amplifies the differential detection signal from the angular velocity sensor element 14, the synchronous detection circuit 81 that synchronously detects the differential signal from the amplification circuit 61, and the differential from the synchronous detection circuit 81. And a filter unit 90 for low-pass filtering the signal. The filter unit 90 is a passive low-pass filter composed of a resistance element and a capacitor.

  The buffer circuit 43 is provided between the nodes NA1P and NA1N at one end of the switch elements SW2P and SW2N and the nodes NB2P and NB2N at the other end.

  At this time, as shown in FIG. 14, the buffer circuit 43 buffers the signals of the nodes NA1P and NA1N (input signals of the A / D conversion unit 100) and outputs them to the nodes NB2P and NB2N in the first period TA1. Then, the end timing ea2 of the second period TA2 is set after the end timing ea1 of the first period TA1.

  The second A / D conversion circuit 104 receives the input signal of the second A / D conversion circuit 104 after the end timing ea1 of the first period TA1 and before the end timing ea2 of the second period TA2. Is sampled.

  Further, the start timing sa2 of the second period TA2 is set after the start timing sa1 of the first period TA1.

  In the present embodiment, a passive low-pass filter (filter unit 90) is provided in front of the switch elements SW2P and SW2N. Therefore, there is a problem that the A / D conversion value becomes inaccurate depending on the relationship between the time constant (cutoff frequency) and the sampling frequency of the second A / D conversion circuit 104.

  Specifically, when a plurality of input signals of the second A / D conversion circuit 104 are switched, the voltages of the plurality of input signals are different. Therefore, the second A / D conversion circuit 104 is switched according to the switching of the input signals. The voltages of the input nodes NB2P and NB2N also change. Therefore, when the switch elements SW2P and SW2N are turned on, the output of the passive low-pass filter once becomes the voltage of the input nodes NB2P and NB2N before switching, and then gradually approaches the output of the original detection circuit 60. This asymptotic speed is determined by the time constant of the passive low-pass filter.

  The cutoff frequency of the passive low-pass filter is set so that the detuning frequency component of the angular velocity sensor element 14 (vibration piece) can be reduced. Basically, the sampling of the second A / D conversion circuit 104 is performed. It is not related to frequency. For this reason, the cutoff frequency of the passive low-pass filter may be slower than the frequency at which the plurality of input signals of the second A / D conversion circuit 104 are switched. In this case, the switch elements SW2P and SW2N are turned off before the switch elements SW2P and SW2N are sufficiently asymptotic to the output of the original detection circuit 60 after the switch elements SW2P and SW2N are turned on. Are not input to the A / D conversion circuit 104.

  In this regard, according to the present embodiment, the buffer circuit 43 buffers the output of the filter unit 90 and drives the input nodes NB2P and NB2N of the second A / D conversion circuit 104. As a result, when the switch elements SW2P and SW2N are turned on, the input nodes NB2P and NB2N can be quickly driven to the same voltage as the output of the filter unit 90. As a result, an accurate A / D conversion value can be obtained even when a circuit having a low driving capability, such as a passive low-pass filter, is provided in front of the switch elements SW2P and SW2N.

9. Detailed Configuration of Electronic Device, Gyro Sensor, and Circuit Device FIG. 15 shows a circuit device 20 of the present embodiment, a gyro sensor 510 (physical quantity detection device in a broad sense) including the circuit device 20, and an electronic device including the gyro sensor 510. 500 detailed configuration examples are shown.

  Note that the circuit device 20, the electronic device 500, and the gyro sensor 510 are not limited to the configuration shown in FIG. 15, and various modifications may be made such as omitting some of the components or adding other components. It is. In addition, as the electronic device 500 of the present embodiment, various devices such as a digital camera, a video camera, a smartphone, a mobile phone, a car navigation system, a robot, a biological information detection device, a game machine, a watch, a health appliance, or a portable information terminal can be used. Equipment can be assumed. In the following description, the physical quantity transducer (angular velocity sensor element) is a piezoelectric vibrating piece (vibrating gyro) and the sensor is a gyro sensor. However, the present invention is not limited to this. For example, the present invention can be applied to a capacitance detection type vibration gyro formed from a silicon substrate or the like, a physical quantity equivalent to angular velocity information, or a physical quantity transducer that detects a physical quantity other than angular velocity information.

  Electronic device 500 includes a gyro sensor 510 and a processing unit 520. Further, a memory 530, an operation unit 540, and a display unit 550 can be included. A processing unit 520 (external processing device) realized by a CPU, MPU, or the like performs control of the gyro sensor 510 and the like and overall control of the electronic device 500. The processing unit 520 performs processing based on angular velocity information (physical quantity in a broad sense) detected by the gyro sensor 510. For example, processing for camera shake correction, posture control, GPS autonomous navigation, and the like is performed based on the angular velocity information. The memory 530 (ROM, RAM, etc.) stores control programs and various data, and functions as a work area and a data storage area. The operation unit 540 is for the user to operate the electronic device 500, and the display unit 550 displays various information to the user.

  The gyro sensor 510 (physical quantity detection device) includes the resonator element 10 and the circuit device 20. The vibrating piece 10 (physical quantity transducer or angular velocity sensor element in a broad sense) is a piezoelectric vibrating piece formed from a thin plate of a piezoelectric material such as quartz. Specifically, the vibrating piece 10 is a double T-shaped vibrating piece formed of a Z-cut quartz substrate.

  The circuit device 20 includes a drive circuit 30, a detection circuit 60, and a control unit 140. Various modifications such as omitting some of these components or adding other components are possible.

  The drive circuit 30 outputs a drive signal DQ to drive the resonator element 10. For example, the vibration piece 10 is excited by receiving the feedback signal DI from the vibration piece 10 and outputting the corresponding drive signal DQ. The detection circuit 60 receives the detection signals IQ1 and IQ2 (detection current and charge) from the vibration piece 10 driven by the drive signal DQ, and receives a desired signal corresponding to the physical quantity applied to the vibration piece 10 from the detection signals IQ1 and IQ2. (Coriolis force signal) is detected (extracted).

  The resonator element 10 includes a base 1, connecting arms 2 and 3, driving arms 4, 5, 6 and 7, and detection arms 8 and 9. The detection arms 8 and 9 extend in the + Y axis direction and the −Y axis direction with respect to the rectangular base 1. Further, the connecting arms 2 and 3 extend in the −X axis direction and the + X axis direction with respect to the base portion 1. The drive arms 4 and 5 extend in the + Y-axis direction and the −Y-axis direction with respect to the connection arm 2, and the drive arms 6 and 7 extend in the + Y-axis direction and the −Y-axis direction with respect to the connection arm 3. ing. The X axis, the Y axis, and the Z axis indicate crystal axes, and are also referred to as an electric axis, a mechanical axis, and an optical axis, respectively.

  The drive signal DQ from the drive circuit 30 is input to the drive electrodes provided on the upper surfaces of the drive arms 4 and 5 and the drive electrodes provided on the side surfaces of the drive arms 6 and 7. In addition, signals from the drive electrodes provided on the side surfaces of the drive arms 4 and 5 and the drive electrodes provided on the upper surfaces of the drive arms 6 and 7 are input to the drive circuit 30 as feedback signals DI. Further, signals from detection electrodes provided on the upper surfaces of the detection arms 8 and 9 are input to the detection circuit 60 as detection signals IQ1 and IQ2. The common electrode provided on the side surfaces of the detection arms 8 and 9 is grounded, for example.

  When an AC drive signal DQ is applied by the drive circuit 30, the drive arms 4, 5, 6, and 7 perform bending vibration (excitation vibration) as indicated by an arrow A due to the inverse piezoelectric effect. That is, the distal ends of the driving arms 4 and 6 repeatedly approach and separate from each other, and the distal ends of the driving arms 5 and 7 also perform bending vibrations that repeatedly approach and separate from each other. At this time, since the driving arms 4 and 5 and the driving arms 6 and 7 are oscillating line-symmetrically with respect to the Y axis passing through the center of gravity of the base 1, the base 1, the connecting arms 2 and 3, and the detection arm 8. , 9 hardly vibrate.

  In this state, when an angular velocity with the Z axis as the rotation axis is applied to the vibrating piece 10 (when the vibrating piece 10 rotates around the Z axis), the driving arms 4, 5, 6, 7 are moved to the arrow B by Coriolis force. Vibrate as shown. That is, the Coriolis force in the direction of the arrow B perpendicular to the direction of the arrow A and the direction of the Z-axis acts on the drive arms 4, 5, 6, and 7, thereby generating a vibration component in the direction of the arrow B. The vibration of the arrow B is transmitted to the base 1 via the connecting arms 2 and 3, and the detection arms 8 and 9 perform bending vibration in the direction of the arrow C. Charge signals generated by the piezoelectric effect due to the bending vibration of the detection arms 8 and 9 are input to the detection circuit 60 as detection signals IQ1 and IQ2. Here, the vibration of the arrow B of the drive arms 4, 5, 6, and 7 is a vibration in the circumferential direction with respect to the center of gravity of the base 1, and the vibration of the detection arms 8 and 9 is It is the vibration in the direction of the arrow C in the opposite direction. The detection signals IQ1 and IQ2 are signals whose phases are shifted by 90 degrees with respect to the drive signal DQ.

  For example, when the angular velocity of the vibrating piece 10 (gyro sensor) around the Z axis is ω, the mass is m, and the vibration velocity is v, the Coriolis force is expressed as Fc = 2 m · v · ω. Therefore, the detection circuit 60 can obtain the angular velocity ω by detecting a desired signal that is a signal corresponding to the Coriolis force. By using the obtained angular velocity ω, the processing unit 520 can perform various processes for camera shake correction, posture control, GPS autonomous navigation, and the like.

  FIG. 15 shows an example in which the resonator element 10 is a double T-shape, but the resonator element 10 of the present embodiment is not limited to such a structure. For example, a tuning fork type, an H type, or the like may be used. In addition, the piezoelectric material of the resonator element 10 may be a material such as ceramics or silicon other than quartz.

  FIG. 16 shows a detailed configuration example of the drive circuit 30 and the detection circuit 60 of the circuit device.

  The drive circuit 30 includes an amplifier circuit 32 to which the feedback signal DI from the vibration piece 10 is input, a gain control circuit 40 that performs automatic gain control, and a drive signal output circuit 50 that outputs the drive signal DQ to the vibration piece 10. . A synchronization signal output circuit 52 that outputs the synchronization signal SYC to the detection circuit 60 is also included. Note that the configuration of the drive circuit 30 is not limited to that shown in FIG. 16, and various modifications such as omitting some of these components or adding other components are possible.

  The amplification circuit 32 (I / V conversion circuit) amplifies the feedback signal DI from the vibration piece 10. For example, a current signal DI from the vibrating piece 10 is converted into a voltage signal DV and output. The amplifier circuit 32 can be realized by an operational amplifier, a feedback resistor element, a feedback capacitor, or the like.

  The drive signal output circuit 50 outputs a drive signal DQ based on the signal DV amplified by the amplifier circuit 32. For example, when the drive signal output circuit 50 outputs a rectangular wave (or sine wave) drive signal, the drive signal output circuit 50 can be realized by a comparator or the like.

  The gain control circuit 40 (AGC) outputs a control voltage DS to the drive signal output circuit 50 to control the amplitude of the drive signal DQ. Specifically, the gain control circuit 40 monitors the signal DV and controls the gain of the oscillation loop. For example, in the drive circuit 30, in order to keep the sensitivity of the gyro sensor constant, it is necessary to keep the amplitude of the drive voltage supplied to the vibration piece 10 (drive vibration piece) constant. Therefore, a gain control circuit 40 for automatically adjusting the gain is provided in the oscillation loop of the drive vibration system. The gain control circuit 40 automatically variably adjusts the gain so that the amplitude of the feedback signal DI from the vibrating piece 10 (vibration speed v of the vibrating piece) is constant. The gain control circuit 40 can be realized by a full-wave rectifier for full-wave rectifying the output signal DV of the amplifier circuit 32, an integrator for integrating the output signal of the full-wave rectifier, or the like.

  The synchronization signal output circuit 52 receives the signal DV amplified by the amplification circuit 32 and outputs a synchronization signal SYC (reference signal) to the detection circuit 60. The synchronization signal output circuit 52 performs a binarization process on the sine wave (alternating current) signal DV to generate a rectangular wave synchronization signal SYC, and a phase adjustment circuit (transition circuit) that adjusts the phase of the synchronization signal SYC. Etc.).

  Although not illustrated in FIG. 16, the circuit device 20 is provided with a clock signal generation circuit that generates a clock signal serving as a master clock, such as the A / D conversion unit 100, the processing unit 110, and the control unit 140. The clock signal generation circuit generates a clock signal using, for example, a CR oscillation circuit, but the present embodiment is not limited to this.

  The detection circuit 60 includes an amplification circuit 61, a synchronous detection circuit 81, and a filter unit 90. The amplifier circuit 61 receives the first and second detection signals IQ1 and IQ2 from the resonator element 10, and performs charge-voltage conversion, differential signal amplification, gain adjustment, and the like. The synchronous detection circuit 81 performs synchronous detection based on the synchronous signal SYC from the drive circuit 30. The filter unit 90 (low-pass filter) functions as a pre-filter for the A / D conversion unit 100. The filter unit 90 also functions as a circuit that attenuates unnecessary signals that could not be removed by synchronous detection. The A / D conversion unit 100 performs A / D conversion of the signal after synchronous detection. The processing unit 110 performs digital signal processing such as digital filter processing and digital correction processing on the digital signal from the A / D conversion unit 100. Examples of digital correction processing include zero point correction processing and sensitivity correction processing.

  For example, the detection signals IQ1 and IQ2 that are charge signals (current signals) from the vibrating piece 10 are delayed in phase by 90 degrees with respect to the drive signal DQ that is a voltage signal. Further, the phase is delayed by 90 degrees in the Q / V conversion circuit of the amplifier circuit 61 and the like. For this reason, the phase of the output signal of the amplifier circuit 61 is delayed by 180 degrees with respect to the drive signal DQ. Therefore, for example, by performing synchronous detection using the synchronization signal SYC in phase with the drive signal DQ (DV), an unnecessary signal whose phase is delayed by 90 degrees with respect to the drive signal DQ can be removed.

  The control unit 140 performs control processing for the circuit device 20. The control unit 140 can be realized by a logic circuit (gate array or the like), a processor, or the like. Various switch controls, mode settings, and the like in the circuit device 20 are performed by the control unit 140.

10. Mobile Object, Electronic Device FIG. 17A shows an example of a mobile object including the circuit device 20 of this embodiment. The circuit device 20 of the present embodiment can be incorporated into various moving bodies such as cars, airplanes, motorcycles, bicycles, and ships. The moving body is a device / device that includes a driving mechanism such as an engine or a motor, a steering mechanism such as a steering wheel or a rudder, and various electronic devices, and moves on the ground, the sky, or the sea. FIG. 17A schematically shows an automobile 206 as a specific example of the moving object. The automobile 206 incorporates a gyro sensor 510 (sensor) having the resonator element 10 and the circuit device 20. The gyro sensor 510 can detect the posture of the vehicle body 207. A detection signal of the gyro sensor 510 is supplied to the vehicle body posture control device 208. The vehicle body posture control device 208 can control the hardness of the suspension and the brakes of the individual wheels 209 according to the posture of the vehicle body 207, for example. In addition, such posture control can be used in various mobile objects such as a biped robot, an aircraft, and a helicopter. The gyro sensor 510 can be incorporated in realizing the attitude control.

  As shown in FIGS. 17B and 17C, the circuit device of this embodiment is a digital still camera, a biological information detection device (wearable health device, such as a pulse meter, pedometer, activity meter, etc.). It can be applied to various electronic devices. For example, camera shake correction using a gyro sensor or an acceleration sensor can be performed in a digital still camera. Further, in the biological information detection apparatus, it is possible to detect a user's body movement or an exercise state using a gyro sensor or an acceleration sensor. As shown in FIG. 17D, the circuit device of this embodiment can also be applied to a movable part (arm, joint) or main body part of a robot. As the robot, any of a moving body (running / walking robot) and an electronic device (non-running / non-walking robot) can be assumed. In the case of a traveling / walking robot, for example, the circuit device of this embodiment can be used for autonomous traveling.

  Although the present embodiment has been described in detail as described above, it will be easily understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention. For example, in the specification or drawings, terms (angular velocity, angular velocity sensor element, gyro sensor, etc.) described at least once together with different terms (physical quantity, physical quantity transducer, physical quantity detection device, etc.) in a broader sense or synonymous Alternatively, the different terms can be used in any place in the drawings. In addition, the configuration of the circuit device, the physical quantity detection device, the electronic device, the moving body, the structure of the vibrating piece, and the like are not limited to those described in the present embodiment, and various modifications can be made.

1 base, 2, 3 connecting arm, 4-7 driving arm, 8, 9 detecting arm, 10 vibrating piece,
12 physical quantity transducers, 14, 15 angular velocity sensor elements,
16 acceleration sensor element, 17 angular velocity sensor element, 18 temperature sensor,
19 angular velocity sensor element, 20 circuit device, 30 drive circuit, 32 amplifier circuit,
40 gain control circuit, 43 buffer circuit, 50 drive signal output circuit,
52 synchronization signal output circuit, 60 detection circuit, 61 amplifier circuit,
62, 65, 67, 69 detection circuit, 81 synchronous detection circuit, 90 filter section,
100 A / D converter, 102 1st A / D converter circuit,
103 successive approximation type A / D conversion circuit, 104 second A / D conversion circuit,
105, 107, 109 delta-sigma modulation type A / D conversion circuit,
110 processing unit, 111 selector, 112 zero point correction unit,
113 gain correction unit, 114 digital filter, 115 correction coefficient selection unit,
116 filter coefficient selection unit, 120 switching control unit, 140 control unit,
142 register section, 144 interface section, 206 automobile,
207 body, 208 body posture control device, 209 wheel, 500 electronic device,
510 gyro sensor, 520 processing unit, 530 memory,
540 operation unit, 550 display unit,
SA1 first input signal, SA2 second input signal,
SW1 first switch element, SW2 second switch element

Claims (14)

A detection circuit that performs detection processing of a detection signal from the physical quantity transducer;
An A / D converter for A / D converting an input signal from the detection circuit;
Including
The A / D converter is
A first A / D conversion circuit;
A second A / D conversion circuit that is different from the first A / D conversion circuit in at least one of an A / D conversion method, a sampling frequency, a resolution, and an input dynamic range;
Have
In the first mode, the first A / D converter circuit A / D converts the input signal,
In the second mode, the second A / D conversion circuit performs A / D conversion on the input signal. In claim 1,
The A / D converter is
A first switch element provided between an input node of the A / D converter and an input node of the first A / D converter circuit, and turned on in the first mode;
A second switch element provided between an input node of the A / D converter and an input node of the second A / D converter circuit, and turned on in the second mode;
A circuit device comprising: In claim 1 or 2,
The second A / D conversion circuit is an A / D conversion circuit that consumes less power than the first A / D conversion circuit,
The second mode is a low power consumption mode,
In the first mode, a signal from the detection circuit is input to the first A / D conversion circuit as the input signal,
In the second mode, the circuit device is characterized in that a signal from the detection circuit is input to the second A / D conversion circuit as the input signal. In any one of Claims 1 thru | or 3,
To the A / D converter, a first input signal that is a signal from the detection circuit and a second input signal that is a signal from a second physical quantity transducer are input as the input signals,
In the first mode, the first input signal is input to the first A / D conversion circuit, the second input signal is input to the second A / D conversion circuit,
In the second mode, the first input signal and the second input signal are input to the second A / D conversion circuit in a time division manner. In claim 4,
The first physical quantity transducer is an angular velocity sensor element;
The circuit device, wherein the second physical quantity transducer is a temperature sensor or an acceleration sensor element. In any one of Claims 1 thru | or 5,
The first A / D conversion circuit is a delta-sigma modulation type A / D conversion circuit,
The circuit device, wherein the second A / D conversion circuit is a successive approximation type A / D conversion circuit. In any one of Claims 1 thru | or 6,
A processing unit for digitally processing the output of the A / D conversion unit;
The processor is
In the first mode, the A / D conversion value of the first A / D conversion circuit is digitally processed by the first processing method,
In the second mode, the A / D conversion value of the second A / D conversion circuit is digitally processed by a second processing method. In claim 7,
The circuit device according to claim 1, wherein the first processing method and the second processing method are different in at least one of digital filter processing and digital correction processing. In any one of Claims 1 thru | or 8,
An interface part;
A register section;
Including
The circuit device, wherein the first mode and the second mode are switched based on a mode setting value set in the register unit via the interface unit. In any one of Claims 1 thru | or 8,
The first mode includes a switching control unit that switches from the first mode to the second mode based on a detection value based on an A / D conversion value of the first A / D conversion circuit. Circuit device to do. In any one of Claims 1 thru | or 8,
The second mode includes a switching control unit that switches from the second mode to the first mode based on a detection value based on an A / D conversion value of the second A / D conversion circuit. Circuit device to do. In any one of Claims 1 thru | or 11,
The first A / D conversion circuit is an A / D conversion circuit that consumes more power than the second A / D conversion circuit;
In the second mode, the first A / D conversion circuit is set to a low power consumption state or an operation disabled state.   An electronic apparatus comprising the circuit device according to claim 1.   A moving body comprising the circuit device according to claim 1.