JP6641712B2 - Circuit device, electronic equipment and moving object - Google Patents

Description

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

  In recent years, motion sensors such as gyro sensors and acceleration sensors have been spotlighted. By using such a motion sensor, for example, camera shake correction of a camera and intuitive operation input in a game machine can be realized. As a prior art of an apparatus that performs an A / D conversion process or a filter process in response to a detection signal from such a physical quantity transducer (sensor element), there is a technology disclosed in, for example, Patent Document 1. In Patent Literature 1, a detection signal from a 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 related art, there is one type of A / D conversion circuit that A / D converts a signal obtained by synchronously detecting 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 the A / D conversion.

  For example, a delta-sigma modulation type A / D conversion circuit, a successive approximation type A / D conversion circuit, 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, but low power consumption is required due to the necessity of an amplifier corresponding to the order and a high operating frequency. It is difficult to convert to electricity. On the other hand, when a successive approximation type A / D conversion circuit is used, the power consumption is relatively low, but the resolution is generally lower than that of a delta-sigma modulation type A / D conversion circuit.

  According to some aspects of the invention, a circuit device, an electronic device, and a moving 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 embodiment 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 of an input signal from the detection circuit. The conversion unit includes a first A / D conversion circuit, and a second A / D conversion circuit in which at least one of an A / D conversion method, a sampling frequency, a resolution, and an input dynamic range is different from the first A / D conversion circuit. A first A / D converter converts the input signal into a digital signal in a first mode, and the second A / D converter converts the input signal into a second mode in the second mode. The present invention relates to a circuit device for A / D converting an input signal.

  According to one embodiment of the present invention, a first A / D conversion circuit and a second A / D conversion circuit having different 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, the sampling frequency, the resolution, and the input dynamic range is different, the power consumption and the accuracy of the A / D conversion of the first A / D conversion circuit and the second A / D conversion circuit are reduced. different. Thus, it is possible to provide a circuit device capable of realizing low power consumption and high accuracy when performing the A / D conversion processing by receiving the detection signal from the 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 or the like.

  In one embodiment of the present invention, the A / D conversion unit is 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 And a first switch element that is turned on in the second mode, and is provided between an input node of the A / D conversion unit and an input node of the second A / D conversion circuit, and is turned on in the second mode. And two 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 conversion circuit is an A / D conversion circuit that consumes less power than the first A / D conversion circuit, and the second mode is low. A power consumption mode, wherein 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 input. May be input to the second A / D conversion circuit as the input signal.

  As described above, the second A / D conversion circuit having lower power consumption than the first A / D conversion circuit is provided, and the second A / D conversion circuit performs the A / D conversion in the second mode. By switching to the second mode, A / D conversion with low power consumption can be realized.

  In one embodiment of the present invention, the A / D converter includes, as the input signals, 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. In the first mode, the first input signal is input to the first A / D conversion circuit, and 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 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, so that the first input signal and the second input signal are converted. A / D conversion can be performed in a time sharing manner. By using the time division, the number of the second A / D conversion circuits provided for the second mode can be reduced to one, and an increase in circuit scale can be suppressed in the mode switching.

  In one aspect of the present 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.

  With 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 used. 2 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 sharing manner. This makes it possible to detect angular velocity with high resolution by setting the first mode, and detect angular velocity and temperature or acceleration with low power consumption by setting the second mode. Will be 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.

  Generally, a delta-sigma modulation type A / D conversion circuit has higher resolution than a successive approximation type A / D conversion circuit, and a successive approximation type A / D conversion circuit has a delta sigma modulation type A / D conversion circuit. The power consumption is lower than that of 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.

  In one embodiment of the present invention, a processing unit for digitally processing an output of the A / D conversion unit is included, and the processing unit includes an A / D converter of the first A / D conversion circuit in the first mode. The conversion value may be digitally processed by a 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 a second processing method.

  As described above, by switching the processing method of digital processing 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.

  In one embodiment of the present invention, the first processing method and the second processing method may differ in at least one of digital filter processing and digital correction processing.

  For example, if the resolution of the A / D conversion circuit is different, the correction value of the digital correction processing 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 unless the filter coefficient is changed. In this regard, according to one aspect of the present invention, at least one of the digital filter processing and the digital correction processing is different between the first mode and the second mode, so that the digital correction processing with an appropriate correction value according to the mode or Digital filter processing with filter coefficients according to the mode can be performed.

  In one embodiment 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 set based on a mode setting value set in the register unit via the interface unit. It may be switched.

  With this 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 via the interface unit. For example, an external processing device can switch between high-resolution A / D conversion and low-power-consumption A / D conversion in accordance with an application, an environment, a 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 by 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 by 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 aspects of the present invention, the switching control unit switches the mode based on the detection value based on the A / D conversion value, thereby switching between the first mode and the second mode. This allows the circuit device to switch between high-resolution A / D conversion and low-power-consumption A / D conversion depending on, 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, and in the second mode, The first A / D conversion circuit may be set to a low power consumption state or an operation disable state.

  The first A / D conversion circuit, which consumes more power than the second A / D conversion circuit, is set to the low power consumption state or the operation disable state in the second mode, so that the second A / D conversion circuit operates in the second mode. Power consumption can be suppressed, and A / D conversion with low power consumption can be performed in the second mode.

  Another embodiment of the present invention relates to an electronic device including any one of the circuit devices described above.

  Another embodiment of the present invention relates to a moving object including any one of the circuit devices described above.

1 is a first configuration example of a circuit device according to an embodiment. 6 is an operation timing chart of the circuit device of the first configuration example. 9 shows a second configuration example of the circuit device of the present embodiment. 9 is an operation timing chart of the circuit device of the second configuration example. 9 shows a third configuration example of the circuit device according to the embodiment. 9 is an operation timing chart of the circuit device of the third configuration example. 14 shows a fourth configuration example of the circuit device of the embodiment. 9 is an operation timing chart of the circuit device of the fourth configuration example. 4 is a detailed configuration example of a processing unit. 14 shows a fifth configuration example of the circuit device of the embodiment. 16 shows a sixth configuration example of the circuit device of the present embodiment. FIG. 14 is an explanatory diagram of the operation of the circuit device of the sixth configuration example. 14 shows a seventh configuration example of the circuit device of the embodiment. 14 is an operation timing chart of the circuit device of the seventh configuration 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. 4 shows a detailed configuration example of a drive circuit and a detection circuit. 17A to 17D illustrate examples of a moving object 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. Note that 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 essential as solving means of the present invention. Not necessarily.

1. First Configuration Example of Circuit Device FIG. 1 shows a first configuration example of the circuit device of the present embodiment. The circuit device 20 includes a detection circuit 60 that performs detection processing of a detection signal SD from the physical quantity transducer 12, and an A / D conversion unit 100 that performs A / D conversion of an input signal SA1 from the detection circuit 60. Note that the A / D converter 100 only needs to be provided after the detection circuit 60, and the output signal of the detection circuit 60 does not need to be directly input to the A / D converter 100. Further, 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 converter 100 includes a first A / D conversion circuit 102 and a second A / D conversion circuit 104. The second A / D conversion circuit 104 differs 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. Then, 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 Performs A / D conversion of 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 thereto) and converts them into an electric signal.

  The input signal SA1 of the A / D converter 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 converter 100, and the output signal of the circuit may be used as the input signal SA1 of the A / D converter 100. .

  The first A / D conversion circuit 102 and the second A / D conversion circuit 104 may differ only in one of an A / D conversion method, a sampling frequency, a resolution, and an input dynamic range, or may differ in a plurality. 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, or the like can be assumed. The sampling frequency is a frequency at which the A / D conversion circuit samples an input signal. Even if the frequency at which the A / D conversion circuit outputs the A / D converted 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 a physical quantity corresponding to one LSB of the A / D converted value, or the magnitude of an input signal corresponding to one LSB of the A / D converted value. Alternatively, the number of bits of the A / D converted value is called the resolution. The input dynamic range is the range of the input signal to be A / D converted.

  The first mode and the second mode are switched by the switching control unit 120. That is, when the switching control unit 120 outputs the mode control signal MDS instructing the first mode, the A / D conversion unit 100 A / D converts the input signal by the first A / D conversion circuit 102, When the switching control unit 120 outputs a mode control signal MDS instructing the second mode, the A / D conversion unit 100 A / D converts 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, and in the first and second modes, the first and second A / D conversion circuits 102 and 104 respectively perform A / D conversion. By performing the 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 differ 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 accuracy of the A / D conversion ( For example, resolution, linearity, S / N, time resolution, etc.) are different. By switching these A / D conversion circuits, it is possible to switch between A / D conversion with high accuracy and A / D conversion with low power consumption as required.

  For example, in a gyro sensor (the physical quantity transducer 12 is an angular velocity sensor element), an angular velocity is integrated to obtain an angle. Therefore, an angular velocity error is integrated to increase an angle error. Therefore, it is desirable to obtain a high-accuracy 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 not be necessary to measure with high accuracy and it may be desirable to reduce power consumption (for example, there is a time when the angular velocity is close to zero, or a time when the change in the 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-precision measurement and low power consumption can be achieved according to the application, environment, situation, and the like.

  In the present embodiment, the A / D conversion unit 100 includes a first switch element SW1 provided between the input node NA1 of the A / D conversion unit 100 and the input node NB1 of the first A / D conversion circuit 102. And a second switch element SW2 provided between the input node NA1 of the A / D conversion unit 100 and the input node NB2 of the second A / D conversion 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 configured by, for example, a transfer gate (a P-type transistor and an N-type transistor are connected in parallel), a P-type transistor, an N-type transistor, and the like. . Further, the nodes NA1, NB1, and NB2 may be differential input nodes, and in that case, a switch element is provided for each of the first node and the second node forming 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, a high level indicates that the switch element is on, and a 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 is turned on. SW2 turns off. On the other hand, when the mode control signal MDS is at the high level (the second logical 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, intermittent ON is possible. 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 turned on continuously.

  In the first mode, while the switch element SW2 is off, the second A / D conversion circuit 104 is set to an operation disable state (operation stop state) or a low power consumption state. In the second mode, while the switch element SW1 is off, the first A / D conversion circuit 102 is set to the operation disable state or the low power consumption state. The operation disable 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, and the like 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 a high resolution mode and a 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 input to the second A / D conversion circuit 102 as the input signal SA1. The signal is input to the A / D conversion circuit 104.

  Examples of the A / D conversion circuits having different power consumption include A / D conversion circuits having different A / D conversion methods, A / D conversion circuits having the same A / D conversion method but different sampling frequencies, and delta-sigma modulation type A. An A / D conversion circuit having an internal configuration different from that of the same A / D conversion method such as the order of the / D conversion circuit is assumed.

  As described above, by providing the second A / D conversion circuit 104 having lower power consumption than the first A / D conversion circuit 102, switching to the second mode can reduce the power consumption of the A / D conversion circuit. Can be realized.

  Further, in the present embodiment, as shown in FIG. 2, the switch element SW2 is turned off intermittently in the second mode, but the second A / D conversion circuit 104 operates while the switch element SW2 is turned off. Set to disable state or low power consumption state. Thus, it is possible to further reduce the power consumption of the second mode as compared with the case where the second A / D conversion circuit 104 continuously performs the 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, the delta-sigma modulation type A / D conversion circuit includes a sampling circuit that samples an input signal, a difference device that outputs a difference between an output of the sampling circuit and an output of the quantizer, and an output of the difference device. , 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 it back to the difference device. This is a configuration for one loop. In the case of second or higher order, the loop has the number of orders. Oversampling is performed at a frequency higher than a desired sampling frequency (output frequency of the A / D conversion value), and the output of the quantizer is downsampled by a decimation filter to output an A / D conversion value.

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

  The delta-sigma modulation type A / D conversion circuit can easily realize high resolution by oversampling, but has a large number of amplifier circuits (for example, an integrator, an amplifier circuit included in a D / A conversion circuit; a secondary circuit). In the above case, the number of amplifiers becomes, for example, the order times) and the sampling frequency is high, so that it is difficult to reduce power consumption. The successive approximation type A / D conversion circuit has a small number of amplifier circuits (for example, an amplifier circuit included in the comparison circuit) and has a low sampling frequency, so that it is easy to reduce power consumption. From the point of view, it is difficult to increase the resolution. As an example, the 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 type A / D conversion 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. Thus, 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 of 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. The same components as those already described are denoted by the same reference numerals, and description thereof will not be repeated.

  The A / D converter 100 includes first and second A / D converter circuits 102 and 104, first and second switch elements SW1 and SW2, and a second input node NA2 of the A / D converter 100. And a third switch element SW3 provided between the input node NB2 and 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 which is a signal from the detection circuit 60 and a second input signal SA2 based on a signal from the second physical quantity transducer. Is done. Then, in the first mode, the first input signal SA1 is input to the first A / D conversion circuit 102, and the second input signal SA2 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 sharing 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, a high level indicates that the switch element is on, and a 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 sharing manner. That is, the second and third switch elements SW2 and SW3 constitute a multiplexer for sequentially selecting 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, when there is a period during which both the first and second switch elements SW1 and SW2 are turned off, even if the second A / D conversion circuit 104 is set to the operation disable state or the 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 the past A / D conversion value, the time from the input of the signal to the time when the A / D conversion value is obtained is shorter than that of the delta-sigma modulation type A / D conversion circuit. Short and suitable for time-sharing operations.

  As described above, 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, so that the first input signal SA1 and the second 2 can be A / D-converted in a time-division manner. By using time division, even if there are a plurality of inputs, only one second A / D conversion circuit 104 needs to be provided, and the first mode and the second mode are added 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 for detecting an 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 signal that depends on temperature and a reference signal that does not depend on temperature 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 for correcting the zero point of the angular velocity and the temperature dependency of the gain. Since the temperature information only needs to have a resolution required for correction, the output of the temperature sensor 18 is A / D converted by the successive approximation type second A / D conversion circuit 104 regardless of the mode. On the other hand, if a high resolution is required, the output of the angular velocity sensor element 14 selects the first mode, performs A / D conversion by the first A / D conversion circuit 102 of the delta sigma modulation type, and outputs a low resolution. In a good case, the second mode is selected and the successive approximation type A / D conversion circuit 104 performs A / D conversion.

  As shown in FIG. 16, for example, a detection circuit 60 that processes a detection signal from the angular velocity sensor element 14 includes an amplification circuit that amplifies the detection signal, a synchronization detection circuit that performs synchronous detection of a signal from the amplification circuit, and a synchronization detection circuit. And a filter unit 90 that performs low-pass filtering on 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 A / D converts 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 performs A / D conversion of the output of the angular velocity sensor element 14 and the output of the acceleration sensor element 16 in a time-sharing manner, and the first A / D conversion circuit 102 Is in the operation disable state, so that 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 of 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. The same components as those already described are denoted by the same reference numerals, and description thereof will not be repeated.

  The acceleration sensor element 16 is an element that detects acceleration, and is, for example, an element of a capacitance detection method, an element of a piezo resistance method, an element of a heat detection method, or the like. The detection circuit 62 that detects and processes 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 for synchronously detecting a signal from the amplifier circuit may be included.

  The A / D converter 100 includes first and second A / D converters 102 and 104, a first input node NC1 of the A / D converter 100, and an input node of the first A / D converter 102. A first switch element SWC1 provided between the first and second input nodes ND1 and ND1 and an input node ND2 of the second A / D conversion circuit 104 between the first to third input nodes NC1 to NC3 of the A / D converter 100. And the second to fourth switch elements SWC2 to SWC4 provided in the first and second switches.

  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 a signal from the temperature sensor 18. And the third input signal SC3. Then, in the first mode, the first input signal SC1 is input to the first A / D conversion circuit 102, and the second and third input signals SC2 and SC3 are input to the second A / D conversion circuit 104. Is 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, a high level indicates that the switch element is on, and a 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-divided. 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 sharing manner. That is, the second to fourth switch elements SWC2 to SWC4 constitute a multiplexer for sequentially selecting the first to third input signals SC1 to SC3.

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

  As described above, even when the combo sensor of the one-axis gyro sensor and the acceleration sensor is configured, the second A / D conversion circuit 104 performs A / D conversion of a plurality of signals in a time-division manner in the second mode. Thus, power consumption can be reduced. Further, since a plurality of signals can be A / D converted by one successive approximation 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 of the present embodiment. The circuit device 20 includes a temperature sensor 18, detection circuits 65, 67, and 69, an A / D conversion unit 100, a processing unit 110, and a switching control unit 120. The same components as those already described are denoted by the same reference numerals, and description thereof will not be repeated.

  The angular velocity sensor elements 15, 17, and 19 are sensor elements that detect angular velocities in three orthogonal axes (X axis, Y axis, and Z axis). The detection circuits 65, 67, and 69 detect and detect 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 successive approximation type A / D conversion circuits. / D conversion circuit 103 (broadly, a second A / D conversion circuit), first to third input nodes NE1 to NE3 of A / D conversion section 100, and 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 converter 100 sequentially. And fourth to seventh switch elements SWE4 to SWE7 provided between the comparison type A / D conversion circuit 103 and the input node NF4.

  The A / D converter 100 has, as input signals, first to third input signals SE1 to SE3, which are signals from the detection circuits 65, 67, 69, and a fourth input, which 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 delta-sigma modulation type A / D conversion circuits 105, 107, and 109, and the fourth input signal SE4 is successive approximation type. The signal is input to the A / D conversion circuit 103. In the second mode, the first to fourth input signals SE1 to SE4 are input to the successive approximation type A / D conversion circuit 103 in a time sharing manner.

  FIG. 8 shows an operation timing chart of the circuit device 20 of FIG. In the chart of the switch elements SWE1 to SWE7, a high level indicates that the switch element is on, and a 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 SWE7 is turned on intermittently. 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 sharing manner. That is, the fourth to seventh switch elements SWE4 to SWE7 constitute a multiplexer for sequentially selecting the first to fourth input signals SE1 to SE4.

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

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

5. Processing Unit Hereinafter, details of the processing unit 110 will be described. The processing unit 110 digitally processes the A / D conversion value of the first A / D conversion circuit 102 in the first mode in the first mode, and performs the second A / D conversion in the second mode. The A / D converted 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 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) or the like, and is realized by a logic circuit such as a gate array. The digital processing performed by the processing unit 110 is, for example, an A / D conversion value filtering process, a correction process, a conversion process, 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, correction of temperature characteristics, and the like are assumed. As the conversion process, for example, a process of converting an A / D conversion value into a physical quantity, a process of converting a characteristic of the A / D conversion value with respect to the physical quantity, a conversion of a sampling frequency, and the like are assumed. The first and second processing methods differ, for example, in the contents and parameters of the digital processing. For example, filter processing and correction processing may be performed in the first processing method, and correction processing and conversion processing may be performed in the second processing method, or both filter processing and correction processing may be performed in the first and second processing methods. Processes may be performed and the parameters for 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 in a case where the digital filter processing and the digital correction processing are different between the first processing method and the second processing method. Note that the configuration of the processing unit 110 is not limited to FIG. 9, and it is sufficient that at least one of the digital filter processing and the digital correction processing differs 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 selects 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 compares 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 the correction value from. The first and second zero point correction values and the first and second gain correction values each have a temperature characteristic, and the correction coefficient selection unit 115 corrects the temperature according to the temperature measured by the temperature sensor. Select a value.

  The zero point correction unit 112 performs a 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 (or subtracted from) the A / D converted 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 out 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 characteristic is set with 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 changes according to the filter coefficient.

  Since the resolution (number of bits) of the A / D conversion value differs between 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, the zero point correction value And the gain correction value are also different. That is, even if the offset and sensitivity are the same on the input side of the A / D conversion circuit, the offset and sensitivity are different in the A / D conversion value due to the difference in resolution (for example, 10 bits for 1 V full scale and A / D for 12 bits). When D-converted, 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 cutoff frequency of the low-pass filter is defined as a ratio to the sampling frequency, and if the sampling frequency doubles, the cutoff frequency doubles (the ratio does not change).

  In this regard, according to the present embodiment, since the 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, the zero point correction and the gain correction can be performed according to the change. Further, even if the sampling frequency changes in accordance with the A / D conversion circuit, the ratio between the cutoff frequency and the sampling frequency can be changed accordingly to set an appropriate cutoff frequency (for example, the same cutoff frequency can be set 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 the present 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. The same components as those already described are denoted by the same reference numerals, and description thereof will not be repeated.

  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, an external processing device can switch between high-resolution A / D conversion and low-power-consumption A / D conversion in accordance with 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 the present 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. The same components as those already described are denoted by the same reference numerals, and description thereof will not be repeated.

  The switching control unit 120 switches from the first mode to the second mode in the first mode based on a 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 a 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 obtain a detection value (physical quantity), and the switching control unit 120 It is determined whether 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 obtain a detection value (physical quantity), and the switching control unit 120 performs the processing based on the detection value. It is determined whether to switch from the second mode to the first mode.

  FIG. 12 is an operation explanatory diagram of the circuit device of FIG. FIG. 12 illustrates an example in which the physical quantity transducer 12 is an angular velocity sensor element (gyro sensor).

  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, when the absolute value of the angular velocity exceeds the first threshold TH1 a plurality of times (two times in the example of FIG. 12) within a period of a predetermined length, the mode is switched from the second mode to the first mode.

  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 during the predetermined length of time (the absolute value of the angular velocity does not exceed the second threshold value TH2 during the predetermined length of time). Switch from the first mode to the second mode.

  As described above, the switching control unit 120 switches between the first mode and the second mode by switching the mode based on the detection value based on the A / D conversion value. Thus, 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 motion of the device equipped with the gyro sensor is large and the angular velocity is large, high-precision detection is performed by the first A / D conversion circuit 102 of the delta-sigma modulation type, and When the angular velocity is small, low power consumption detection can be performed. By monitoring the angular velocity with low power consumption detection when the movement is small, power consumption can be saved, and when the movement becomes large, it is possible to shift to high precision detection.

8. Seventh Configuration Example of Circuit Device FIG. 13 shows a seventh configuration example of the circuit device of the present 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, illustration of the first A / D conversion circuit 102, the processing unit 110, and the like is omitted. The same components as those already described are denoted by the same reference numerals, and description thereof will not be repeated.

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

  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 made 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 includes an amplification circuit 61 that amplifies a differential detection signal from the angular velocity sensor element 14, a synchronization detection circuit 81 that synchronously detects the differential signal from the amplification circuit 61, and a differential signal from the synchronization detection circuit 81. And a filter unit 90 that performs low-pass filtering on the signal. The filter unit 90 is a passive low-pass filter including a resistance element and a capacitor.

  The buffer circuit 43 is provided between the nodes NA1P, NA1N at one end of the switch elements SW2P, SW2N and the nodes NB2P, 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 converter 100) in the first period TA1, and outputs the signals to the nodes NB2P and NB2N. Then, the end timing ea2 of the second period TA2 is set after the end timing ea1 of the first period TA1.

  Further, 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.

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

  Now, 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. 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 temporarily becomes the voltage of the input nodes NB2P and NB2N before the switch is switched, and thereafter 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 cut-off frequency of the passive low-pass filter is set so as to reduce the component of the detuning frequency of the angular velocity sensor element 14 (the vibrating bar), and basically, the sampling of the second A / D conversion circuit 104 is performed. Not related to frequency. Therefore, the cutoff frequency of the passive low-pass filter may be lower than the frequency at which the plurality of input signals of the second A / D conversion circuit 104 are switched. In this case, the switching elements SW2P and SW2N are turned off before the output of the original detection circuit 60 becomes sufficiently close to the original output of the detection circuit 60 after the switching elements SW2P and SW2N are turned on, and the output of the original detection circuit 60 becomes Is 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. This allows the input nodes NB2P, NB2N to be quickly driven to the same voltage as the output of the filter unit 90 when the switch elements SW2P, SW2N are turned on. Thus, 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 before 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 shows a detailed configuration example.

  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 can 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 types of digital cameras, video cameras, smartphones, mobile phones, car navigation systems, robots, biological information detecting devices, game machines, watches, health appliances, portable information terminals, and the like can be used. Equipment can be assumed. In the following, a case where the physical quantity transducer (angular velocity sensor element) is a piezoelectric vibrating piece (vibrating gyro) and the sensor is a gyro sensor will be described as an example, but the present invention is not limited to this. For example, the present invention can be applied to a vibration gyro of a capacitance detection method formed from a silicon substrate or the like, a physical quantity transducer that detects a physical quantity equivalent to angular velocity information or a physical quantity other than angular velocity information, and the like.

  The electronic device 500 includes a gyro sensor 510 and a processing unit 520. In addition, it can include a memory 530, an operation unit 540, and a display unit 550. A processing unit 520 (external processing device) realized by a CPU, an MPU, and 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, attitude control, GPS autonomous navigation, and the like is performed based on angular velocity information. The memory 530 (ROM, RAM, etc.) stores a control program and various data, and functions as a work area and a data storage area. The operation unit 540 is for the user to operate the electronic device 500, and the display unit 550 displays various information to the user.

  The gyro sensor 510 (physical quantity detection device) includes the resonator element 10 and the circuit device 20. The resonator element 10 (physical quantity transducer, angular velocity sensor element in a broad sense) is a piezoelectric resonator element formed from a thin plate of a piezoelectric material such as quartz. Specifically, the resonator element 10 is a double T-shaped resonator element 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 can be made, such as omitting some of these components or adding other components.

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

  The resonator element 10 has a base 1, connecting arms 2 and 3, driving arms 4, 5, 6 and 7, and detecting arms 8 and 9. Detection arms 8 and 9 extend in the + Y axis direction and the −Y axis direction with respect to the rectangular base 1. The connecting arms 2 and 3 extend in the −X axis direction and the + X axis direction with respect to the base 1. The driving arms 4 and 5 extend in the + Y axis direction and the −Y axis direction with respect to the connecting arm 2, and the driving arms 6 and 7 extend in the + Y axis direction and the −Y axis direction with respect to the connecting arm 3. ing. The X, Y, and Z axes indicate the axes of the quartz crystal, and are also called the electrical axis, the mechanical axis, and the 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. Also, 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. Also, 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 electrodes provided on the side surfaces of the detection arms 8 and 9 are 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 by the inverse piezoelectric effect. That is, the distal ends of the drive arms 4 and 6 repeatedly approach and separate from each other, and the distal ends of the drive arms 5 and 7 also perform bending vibration that alternately approach and separate from each other. At this time, since the driving arms 4 and 5 and the driving arms 6 and 7 are vibrating line-symmetrically with respect to the Y axis passing through the position of the center of gravity of the base 1, the base 1, the connecting arms 2, 3 and the detecting arm 8 , 9 hardly vibrate.

  In this state, when an angular velocity about the Z axis as a rotation axis is applied to the vibrating piece 10 (when the vibrating piece 10 rotates around the Z axis), the drive arms 4, 5, 6, and 7 move to the arrow B by Coriolis force. Vibrates 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, 7 to generate 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, 7 is a vibration in the circumferential direction with respect to the position of the center of gravity of the base 1, and the vibration of the detection arms 8, 9 is in the circumferential direction with respect to the arrow B. Vibration in the direction of 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, if the angular velocity of the resonator element 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 = 2m · v · ω. Accordingly, the detection circuit 60 detects the desired signal which is a signal corresponding to the Coriolis force, whereby the angular velocity ω can be obtained. By using the obtained angular velocity ω, the processing unit 520 can perform various processes for camera shake correction, attitude control, GPS autonomous navigation, and the like.

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

  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 a feedback signal DI from the resonator element 10 is input, a gain control circuit 40 that performs automatic gain control, and a drive signal output circuit 50 that outputs a drive signal DQ to the resonator element 10. . Also, a synchronization signal output circuit 52 that outputs the synchronization signal SYC to the detection circuit 60 is included. Note that the configuration of the drive circuit 30 is not limited to FIG. 16, and various modifications can be made such as omitting some of these components or adding other components.

  The amplification circuit 32 (I / V conversion circuit) amplifies the feedback signal DI from the resonator element 10. For example, it converts a current signal DI from the resonator element 10 into a voltage signal DV and outputs the signal. This amplifier circuit 32 can be realized by an operational amplifier, a feedback resistor, a feedback capacitor, and 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 drive signal of a rectangular wave (or a sine wave), the drive signal output circuit 50 can be realized by a comparator or the like.

  Gain control circuit 40 (AGC) outputs control voltage DS to drive signal output circuit 50 to control the amplitude of 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 resonator element 10 (drive resonator element) 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 variably and automatically adjusts the gain so that the amplitude of the feedback signal DI from the resonator element 10 (the vibration velocity v of the resonator element) becomes constant. The gain control circuit 40 can be realized by a full-wave rectifier that performs full-wave rectification on the output signal DV of the amplifier circuit 32, an integrator that performs integration processing of the output signal of the full-wave rectifier, and 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 (AC) signal DV to generate a rectangular wave synchronization signal SYC, and a phase adjustment circuit (shifter) that adjusts the phase of the synchronization signal SYC. Phaser).

  Although not shown in FIG. 16, 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, is provided in the circuit device 20. 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 synchronization 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 cannot be completely removed by synchronous detection. The A / D converter 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. The digital correction processing includes, for example, a zero point correction processing and a sensitivity correction processing.

  Note that, for example, the detection signals IQ1 and IQ2, which are charge signals (current signals) from the resonator element 10, have a phase lag of 90 degrees with respect to the drive signal DQ which is a voltage signal. Further, the phase is delayed by 90 degrees in the Q / V conversion circuit and the like of the amplification circuit 61. Therefore, the output signal of the amplifier circuit 61 is delayed by 180 degrees in phase with respect to the drive signal DQ. Therefore, for example, by performing synchronous detection using the synchronization signal SYC having the same phase as the drive signal DQ (DV), it becomes possible to remove unnecessary signals and the like whose phase is delayed by 90 degrees with respect to the drive signal DQ.

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

10. Moving Object, Electronic Equipment FIG. 17A illustrates an example of a moving object including the circuit device 20 of the present embodiment. The circuit device 20 of the present embodiment can be incorporated in various moving objects such as a car, an airplane, a motorcycle, a bicycle, and a ship. The moving body is a device or a 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, in the sky, or on the sea. FIG. 17A schematically shows an automobile 206 as a specific example of a moving object. A gyro sensor 510 (sensor) having the resonator element 10 and the circuit device 20 is incorporated in the automobile 206. The gyro sensor 510 can detect the posture of the vehicle body 207. The detection signal of the gyro sensor 510 is supplied to the vehicle body attitude control device 208. The vehicle body attitude control device 208 can control the hardness of the suspension or control the brake of each wheel 209 according to the attitude of the vehicle body 207, for example. In addition, such posture control can be used in various moving objects such as a biped robot, an aircraft, and a helicopter. The gyro sensor 510 can be incorporated in implementing the attitude control.

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

  Although the present embodiment has been described in detail as described above, those skilled in the art can easily understand that many modifications that do not substantially depart from the novel matter and effects of the present invention are possible. Therefore, such modifications are all included in the scope of the present invention. For example, in the description or drawings, terms (angular velocity, angular velocity sensor element, gyro sensor, etc.) described at least once together with different terms that are broader or synonymous (physical quantities, physical quantity transducers, physical quantity detecting devices, etc.) are described in the specification. Alternatively, the different terms can be substituted in any part of the drawings. Further, the configuration of the circuit device, the physical quantity detection device, the electronic device, the moving body, the structure of the resonator element, 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 reed,
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 amplification circuit,
62, 65, 67, 69 detection circuit, 81 synchronous detection circuit, 90 filter section,
100 A / D conversion unit, 102 first A / D conversion 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 unit, 144 interface unit, 206 car,
207 vehicle body, 208 vehicle body attitude control device, 209 wheels, 500 electronic devices,
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 (13)

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 includes:
A first A / D conversion circuit;
A second A / D conversion circuit having at least one of an A / D conversion method, a sampling frequency, a resolution, and an input dynamic range different from the first A / D conversion circuit;
Has,
The front SL A / D conversion section, as the input signal, a first input signal which is a signal from the detection circuit, and a second input signal which is a signal from the second physical quantity transducer is input ,
In a first mode, the first input signal is input to the first A / D conversion circuit, and the first A / D conversion circuit performs A / D conversion on the first input signal, and A / D conversion of the second input signal is not performed, the second input signal is input to the second A / D conversion circuit, and the second A / D conversion circuit converts the second input signal to the second input signal. A / D-converting and not A / D-converting the first input signal,
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 , and the second A / D conversion circuit A / D conversion is performed on the input signal and the second input signal in a time-division manner, and the first A / D conversion circuit does not A / D convert the first input signal and the second input signal. Characteristic circuit device. In claim 1,
The circuit device according to claim 1, wherein in the first mode, the second A / D conversion circuit intermittently performs A / D conversion on the second input signal. In claim 1 or 2 ,
The 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 to 3,
The first A / D conversion circuit, Ri A / D conversion circuit der delta-sigma modulation,
Said second A / D conversion circuit, the circuit device according to claim that it is an A / D converter of the successive approximation type. In any one of claims 1 to 4,
A processing unit for digitally processing an output of the A / D conversion unit;
In the first mode, the first A / D conversion circuit performs A / D conversion on the input signal, and the processing unit converts the A / D conversion value of the first A / D conversion circuit into a first value. Digital processing with the processing method of
In the second mode, the second A / D conversion circuit performs A / D conversion on the input signal, and the processing unit converts the A / D conversion value of the second A / D conversion circuit into a second signal. Digital processing with the processing method of
The circuit device according to claim 1, wherein at least one of digital filter processing and digital correction processing is different between the first processing method and the second processing method. In any one of claims 1 to 5 ,
In the first mode, 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 is included. Circuit device. In any one of claims 1 to 5 ,
In the second mode, 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 is provided. Circuit device. In any one of claims 1 to 5,
An interface section,
A register section,
Including
Circuit device wherein said first mode and said second mode is switched based on the previous SL interface mode setting value set in the register unit through the. In any one of claims 1 to 8 ,
The A / D converter includes:
A first switch element that is provided between a first input node to which the first input signal is input and an input node of the first A / D conversion circuit and that is turned on in the first mode; ,
A second switch element that is provided between the first input node and the input node of the second A / D converter circuit,
A third switch element provided between a second input node to which the second input signal is input and an input node of the second A / D conversion circuit;
Have a,
The circuit device , wherein the second switch element and the third switch element are turned on in a time-sharing manner in the second mode . In any one of claims 1 to 9 ,
The second A / D conversion circuit is an A / D conversion circuit that consumes less power than the first A / D conversion circuit,
The circuit device according to claim 2, wherein the second mode is a low power consumption mode. In any one of claims 1 to 10 ,
The first A / D conversion circuit is an A / D conversion circuit that consumes more power than the second A / D conversion circuit,
The circuit device according to claim 2, wherein in the second mode, the first A / D conversion circuit is set to a low power consumption state or an operation disable state. An electronic apparatus comprising a circuit arrangement as claimed in any one of claims 1 to 11. Mobile body characterized by comprising been circuit device according to any one of claims 1 to 11.