JP2007285958A - Sensor circuit for gyro-sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of a sensor output causing it to look as though angular velocity has been generated, even though angular velocity has not been generated without requiring a special component which is a vibration-proof member. <P>SOLUTION: The time when obtaining an gyro-output and that of performing acceleration detection are switched by switches 150a-150c and a time-division switching circuit 151, and it is detected whether or not the gyro-sensor 1 has generated the acceleration output. When the acceleration output is detected, a drive voltage generated by a drive voltage generating circuit 121 is corrected based on the acceleration output, and the acceleration output is canceled to the gyro-sensor 1. Thereby, the acceleration output of the gyro-sensor 1 can be canceled and it is prevented that the occurrence of a sensor output causing it to look as though angular velocity has been generated, even though angular velocity has not been generated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sensor circuit of a gyro sensor that detects an angular velocity of a vehicle or the like.

  Conventionally, a gyro sensor that detects angular velocity of a vehicle or the like is known. In this gyro sensor, the sensor output may be generated due to the input of acceleration due to an external impact or the like even though the angular velocity is not input. In the sensor output, two symmetrical vibrators are generally canceled in the gyro sensor. Ideally, the two vibrators move in the same way to cancel the influence of acceleration. Even in such a gyro sensor having two vibrators, since the two vibrators do not actually have the same shape, left and right imbalances occur, and as a result, acceleration input causes It will cause a bug. For this reason, it has been studied to provide a vibration isolating structure for the gyro sensor so as not to vibrate against such an impact.

For example, in Patent Document 1, a vibration isolating rubber as a vibration isolating member is provided in a gyro sensor package, and the sensor element is supported by the anti-vibration rubber so as to absorb unnecessary vibration due to an impact from outside. I have to. There is also a method of using silicon oil to attenuate the vibration caused by the input of acceleration.
JP 2000-55667 A

  However, a special component called an anti-vibration member is required, which complicates the configuration of the gyro sensor and consequently increases the manufacturing cost of the gyro sensor.

  In view of the above points, the present invention can prevent generation of a sensor output in which angular velocity is generated even though the angular velocity is not generated even if a special component such as a vibration isolating member is not required. An object of the present invention is to provide a sensor circuit of a gyro sensor.

  In order to achieve the above object, in the present invention, a signal corresponding to a change in capacitance formed between the movable electrode (38, 48) for detecting angular velocity and the fixed electrode (37, 47) is used as an angular velocity detection signal, A capacitance formed between the angular velocity detection circuit (130) that obtains a gyro output by processing the angular velocity detection signal, and the movable electrode (38, 48) and the fixed electrode (37, 47) for angular velocity detection. An acceleration detection circuit (140) that obtains an acceleration output by processing a signal corresponding to the change as an acceleration detection signal and processing the acceleration detection signal, an angular velocity detection movable electrode (38, 48), and a fixed electrode (37, 47) switches (150a to 15a) for switching between switching to the angular velocity detection circuit (130) or switching to the acceleration detection circuit (140) indicating a change in capacitance formed between c) and a switching circuit (151), and based on the acceleration output obtained by the acceleration detection circuit (140), a driving fixed electrode (30, 40) and a driving movable electrode (31, 41) The driving voltage applied during the period is corrected to cancel the acceleration.

  As described above, when the gyro output is obtained and when the acceleration is detected are switched by the switches (150a to 150c) and the switching circuit (151), and it is detected whether or not the gyro sensor (1) generates the acceleration output. I am doing so. When the acceleration output is detected, the driving voltage applied between the driving fixed electrodes (30, 40) and the driving movable electrodes (31, 41) is corrected based on the acceleration output, and the gyro sensor ( The acceleration output is canceled with respect to 1). Thereby, the acceleration output of the gyro sensor (1) can be canceled, and it can be prevented that the sensor output in which the angular velocity is generated although the angular velocity is not generated is generated.

  Such a feature is, for example, that the vibrator (3, 4) includes a pair of left and right vibrators (3, 4), and the left vibrator (3) and the right vibrator (4) are both Each component constituting the left and right vibrators (3, 4) has a left-right symmetric structure in which the left half and the right half are symmetric. A fixed electrode for driving in each of the left and right vibrators (3, 4) (30, 40) and the drive movable electrode (31, 41) by applying a drive voltage, at least a part (31, 34, 41, 44,) of the movable part is supported on the support substrate (2). The present invention can be applied to a gyro sensor that is configured to vibrate in one direction parallel to the substrate surface.

  Further, as the switching circuit, a time division switching circuit (151) for controlling on / off of the switches (150a to 150c) at a predetermined cycle can be used.

  In addition, regarding the correction of the driving voltage applied between the driving fixed electrode (30, 40) and the driving movable electrode (31, 41), for example, the driving voltage is applied to the support substrate (2). In addition to the driving pads (30c, 40c), a pad for applying a voltage corresponding to the acceleration output obtained by the acceleration detection circuit (140) is provided, and a voltage corresponding to the acceleration output is provided to this pad This can be done by applying.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
A schematic diagram of an electrostatic drive / capacitance detection type micro gyro sensor (hereinafter simply referred to as a gyro sensor) as a capacitive angular velocity sensor to which an embodiment of the present invention is applied is shown in FIG. 1 and FIG. AA sectional drawing of FIG. 1 is shown. Hereinafter, the gyro sensor of the present embodiment will be described with reference to these drawings.

  As shown in FIG. 1, the gyro sensor 1 includes two vibrators 3 and 4 on a support substrate 2 made of a semiconductor. In FIG. 1, the left vibrator in FIG. 1 is the left vibrator 3, the right vibrator in the paper is the right vibrator 4, and each of the vibrators 3 and 4 has a symmetrical structure.

  Hereinafter, the structure of the left and right vibrators 3 and 4 will be described. Since the structures of the vibrators 3 and 4 are exactly the same, the structure of the left vibrator 3 will be described here, and the structure of the right vibrator 4 will be described. Omitted.

  The left vibrator 3 includes a fixed electrode 30 and a movable electrode 31 for driving, a fixed electrode 32 and a movable electrode 33 for vibration detection, a weight 34, a detection beam 35, a driving beam 36, a fixed electrode 37 for detecting an angular velocity, and a movable electrode. An electrode 38 is included, and these components are surrounded by a frame 39. Each of these constituent elements has a left-right symmetric structure that is symmetric between the left half and the right half of the drawing. Among these components, the fixed electrode 30 for driving, the fixed electrode 32 for detecting driving vibration, the fixed electrode 37 for detecting angular velocity, and the frame portion 39 correspond to a fixed portion fixed to the support substrate 2. Is. The driving movable electrode 31, the vibration detecting movable electrode 33, the weight 34, the detection beam 35, the driving beam 36, and the angular velocity detecting movable electrode 38 are in a direction parallel to the substrate surface of the support substrate 2. It corresponds to a movable part that can move.

  A total of four fixed electrodes 30 for driving are provided, approximately two at the upper and lower positions at a substantially central position of the left vibrator 3. Each fixed electrode 30 is supported so as to be fixed to the support substrate 2 as shown in FIG. 2, and has a shape divided into two forks inside the frame portion 39 as shown in FIG. Yes. And it has the structure by which the base part 30a and the comb-tooth part 30b were provided in each part divided into two parts. The base portion 30a is extended toward the central portion of the left vibrator 3 with the vertical direction on the paper surface as the longitudinal direction, and the comb tooth portion 30b is perpendicular to the longitudinal direction of the base portion 30a on one side surface of the base portion 30a. It is provided with a plurality of protruding in the direction. Each fixed electrode 30 is electrically connected to a driving pad 30c provided in the frame portion 39, and a driving voltage is applied through the driving pad 30c.

  A total of eight movable electrodes 31 for driving are provided in the upper and lower four positions so as to face each base portion 30a of the fixed electrode 30 for driving at a substantially central position of the left vibrator 3. The driving movable electrode 31 is in a floating state with respect to the support substrate 2 as shown in FIG. 2, and is integrated with the weight portion 34 as shown in FIG. Each movable electrode 31 includes a base portion 31a and a comb tooth portion 31b. The base portion 31a extends from the weight portion 34 to the top and bottom of the left vibrator 3 with the vertical direction on the paper as the longitudinal direction, and the comb tooth portion 31b is one side surface of the base portion 31a, specifically, a fixed electrode. In the surface which opposes the comb-tooth part 30b in 30, it is provided in the state which protruded in the direction perpendicular | vertical to the longitudinal direction of the base | substrate part 31a. For this reason, the comb-tooth part 31b of each movable electrode 31 and the comb-tooth part 30b of each fixed electrode 30 are the states arrange | positioned alternately at predetermined intervals.

  A total of four fixed electrodes 32 for driving vibration detection are provided, two at the top and bottom at positions outside the fixed electrode 30 for driving and the movable electrode 31. Each fixed electrode 32 is supported so as to be fixed to the support substrate 2 as shown in FIG. Each fixed electrode 32 includes a base portion 32a and a comb tooth portion 32b. The base portion 32a is extended toward the central portion of the left vibrator 3 with the vertical direction on the paper surface as the longitudinal direction, and the comb-tooth portion 32b is a longitudinal direction of the base portion 32a on one side surface of the tip portion of the base portion 32a. Are provided in a state protruding in a direction perpendicular to the vertical direction. Each fixed electrode 32 is electrically connected to a vibration detection pad 32c provided in the frame 39, and the potential of the fixed electrode 32 can be measured through the vibration detection pad 32c. ing.

  A total of four movable electrodes 33 for detecting drive vibrations are arranged on both sides of the weight part 34, two above and below so as to face each base part 32a of the fixed electrode 32 for detecting drive vibrations. . Each movable electrode 33 is in a floating state with respect to the support substrate 2 as shown in FIG. 2, and is integrated with the weight portion 34 as shown in FIG. Each movable electrode 33 includes a base portion 33a and a comb tooth portion 33b. The base portion 33a extends from the weight portion 34 to the top and bottom of the left vibrator 3 with the vertical direction on the paper as the longitudinal direction, and the comb tooth portion 33b is one side surface of the base portion 33a, specifically, a fixed electrode. 32 is provided in a state in which a plurality of protrusions protrude in the direction perpendicular to the longitudinal direction of the base portion 33a on the surface facing the comb teeth portion 32b. For this reason, the comb-teeth part 33b of each movable electrode 33 and the comb-teeth part 32b of each fixed electrode 32 are alternately arranged at a predetermined interval.

  The weight 34 is disposed between the driving fixed electrodes 30. The weight portion 34 extends in the left-right direction on the paper surface as a longitudinal direction, and is in a floating state with respect to the support substrate 2.

  The detection beams 35 are arranged at substantially four corners of the left vibrator 3. The detection beam 35 is a cantilever beam with respect to the support substrate 2, and is supported on the support substrate 2 by a support portion 35 b extending from the frame portion 39 side. Thereby, each element which comprises a movable part is supported with respect to the support substrate 2. FIG. The detection beam 35 is electrically connected to an angular velocity detection pad 35a via a support portion 35b. A predetermined voltage can be applied to the movable electrode 31 for driving, the movable electrode 33 for detecting driving vibration, and the movable electrode 38 for detecting angular velocity through the angular velocity detecting pad 35a.

  The driving beam 36 connects the movable electrode 33 for vibration detection and the movable electrode 38 for angular velocity detection, and includes a plurality of beam portions whose longitudinal direction is the vertical direction on the paper surface. The movable electrode 33 for vibration detection can be moved in the left-right direction on the paper surface by a plurality of beam portions. For this reason, the weight 34 integrated with the movable electrode 33 for vibration detection and the movable electrode 31 for driving integrated with the weight 34 can be moved in the left-right direction on the paper surface.

  A total of four angular velocity detection fixed electrodes 37 are provided on the left and right sides of the left vibrator 3, two on each side. Each fixed electrode 37 is supported so as to be fixed to the support substrate 2 as shown in FIG. Each fixed electrode 37 includes a base portion 37a and a comb tooth portion 37b. The base portion 37a is extended toward the central portion of the left vibrator 3 with the vertical direction on the paper surface as the longitudinal direction, and the comb teeth portion 37b is perpendicular to the longitudinal direction of the base portion 37a on one side surface of the base portion 37a. It is provided with a plurality of protruding in the direction. Each fixed electrode 37 is electrically connected to an angular velocity detection pad 37c provided in the frame portion 39, and the potential of the angular velocity detection fixed electrode 37 can be measured through the angular velocity detection pad 37c. It has become.

  One of the movable electrodes 38 for detecting angular velocity is arranged on both sides of the weight portion 34 so as to face each fixed electrode 37 for detecting angular velocity, and a total of two are provided. Each movable electrode 38 is in a floating state with respect to the support substrate 2 as shown in FIG. 2, and is integrated with the weight portion 34, the drive beam 36, and the like as shown in FIG. Each movable electrode 38 includes a base portion 38a and a comb tooth portion 38b. The base portion 38a is extended from the upper side position to the lower side position in the frame portion 39 with the vertical direction on the paper surface as the longitudinal direction, and the comb-tooth portion 38b is one side surface, specifically, fixed. A plurality of the electrodes 37 are provided in a state of projecting in a direction perpendicular to the longitudinal direction of the base portion 38a on the surface of the electrode 37 facing the comb teeth portion 37b. For this reason, the comb-tooth portions 38b of the movable electrodes 38 and the comb-tooth portions 37b of the fixed electrodes 37 are alternately arranged at predetermined intervals.

  The frame portion 39 is configured to surround the left and right vibrators 3 and 4 and is fixed to the support substrate 2 as shown in FIG. The frame portion 39 is held at a constant potential via a pad 39a. With this configuration, the gyro sensor 1 of the present embodiment is configured.

  The right vibrator 4 has the same configuration as the left vibrator 3 and has the following correspondence relationship. The driving fixed electrode 30 and the movable electrode 31 correspond to the fixed electrode 40 and the movable electrode 41. The fixed electrode 32 and the movable electrode 33 for vibration detection correspond to the fixed electrode 42 and the movable electrode 43. The weight portion 34 corresponds to the weight portion 44, and the detection beam 35 corresponds to the detection beam 45. The drive beam 36 corresponds to the drive beam 36, and the movable electrode 37 and the fixed electrode 38 for angular velocity detection correspond to the movable electrode 47 and the fixed electrode 48. The frame part 39 corresponds to the frame part 49. In addition, regarding the detailed configuration of the base portion 40a and the comb teeth portion 40b that constitute each part of the right vibrator 4, the reference numerals in the thirties for the left vibrator 3 in the figure are changed to the 40th. Shown as modified.

  Next, a sensor circuit used for driving the gyro sensor 1 and detecting a change in the detection capacity of the gyro sensor 1 according to the present embodiment will be described. FIG. 3 shows a block configuration of the sensor circuit 110, which will be described with reference to this figure.

  As shown in FIG. 3, the sensor circuit 110 is configured to include a drive circuit 120 and an angular velocity detection circuit 130.

  The drive circuit 120 is for vibrating the drive movable electrodes 31 and 41 in the vibrators 3 and 4 provided in the gyro sensor 1. The drive circuit 120 includes a drive voltage generation circuit 121 including a sensor drive power supply, a CV conversion circuit 122, a phase shifter 123, and a constant amplitude control unit 124.

  The drive voltage generation circuit 121 forms a voltage for oscillating the drive movable electrodes 31 and 41 in the gyro sensor 1 by boosting the voltage from the sensor drive power supply, and the drive movable electrodes 31 and 41. Is driven at a predetermined amplitude and a predetermined frequency, the voltage generated by the sensor driving power supply is boosted, and a voltage having a predetermined frequency is output as a driving voltage (driving signal) to the driving movable electrodes 31 and 41. Specifically, the drive voltage generated by the drive voltage generation circuit 121 is adjusted based on the drive voltage fed back via the CV conversion circuit 122 and the signal from the constant amplitude control unit 124. .

  The CV conversion circuit 122 receives a detection signal (hereinafter referred to as a drive vibration detection signal) corresponding to the drive vibration of the movable electrodes 31 and 41 for driving in the gyro sensor 1 from the gyro sensor 1 and converts the voltage into voltage. Is. The drive vibration detection signal voltage-converted by the CV conversion circuit 122 is input to the constant amplitude control unit 124 and the phase shifter 123.

  The phase shifter 123 is for adjusting the phase of the drive voltage. Since the drive voltage is generated by the drive voltage generation circuit 121 based on the drive vibration detection signal fed back as described above, the phase of the drive vibration detection signal is actually output to the movable electrodes 31 and 41 for driving. The drive voltage is out of phase with the desired drive voltage. In order to repair this phase shift, the phase of the drive vibration detection signal must be adjusted to match the phase of the drive voltage. For this reason, the phase of the drive vibration detection signal is corrected by the phase shifter 123, and as a result, the phase of the drive voltage formed based thereon is adjusted. Thereby, the frequency of the drive voltage is set to fd.

  The constant amplitude control unit 124 detects the current amplitude of the movable electrodes 31 and 41 for driving from the driving vibration detection signal and outputs a signal for correcting the amplitude to be constant to the driving voltage generation circuit 121. To do.

  The angular velocity detection circuit 130 is for obtaining a sensor output based on the detection signal of the gyro sensor 1. The angular velocity detection circuit 130 includes two CV conversion circuits 131 and 132, a differential amplifier circuit 133, a synchronous detection circuit 134, an LPF 135, and a zero point / sensitivity temperature special adjustment circuit 136.

  The two CV conversion circuits 131 and 132 detect detection signals (hereinafter referred to as vibration signals) generated when an angular velocity is applied to the movable electrodes 38 and 48 for detecting the angular velocity from the pair of vibrators 3 and 4, respectively. , Which is called an angular velocity detection signal) and converts it into a voltage. The angular velocity detection signals after voltage conversion by these CV conversion circuits 131 and 132 are input to the differential amplifier circuit 133.

  The differential amplifier circuit 133 generates a differential output of the angular velocity detection signal after voltage conversion by the CV conversion circuits 131 and 132. The differential output of the differential amplifier circuit 133 is input to the synchronous detection circuit 134. The differential output of the differential amplifier circuit 133 becomes an AC signal including a predetermined offset voltage that becomes a DC component.

  Based on the phase adjusted by the phase shifter 123, the synchronous detection circuit 134 passes a component synchronized with the frequency fd from the differential output of the differential amplifier circuit 133, and outputs it to the LPF 135.

  The LPF 135 extracts only components having a predetermined frequency or less from the signal after passing through the synchronous detection circuit 134. Since the signal is passed through the LPF 135, a time delay corresponding to the filter constant of the LPF 135 occurs.

  The zero point / sensitivity temperature special adjusting circuit 136 adjusts the signal after passing through the LPF 135 because the output offset and sensitivity temperature characteristics are also included. The signal after being adjusted by the zero point / sensitivity temperature special adjustment circuit 136 is basically used as a sensor output.

  Further, the sensor circuit 110 of the gyro sensor 1 of the present embodiment includes an acceleration detection circuit 140, and includes switches 150a to 150c and a time division switching circuit 151.

  The acceleration detection circuit 140 is a circuit that outputs a detection signal corresponding to the acceleration input to the gyro sensor 1. In the present embodiment, the acceleration detection circuit 140 is configured to have a CV conversion circuit 141, and a displacement in one direction of the gyro sensor 1 is taken out as a displacement corresponding to the acceleration, and is used as an acceleration detection signal. By inputting to the charge amplifier circuit 141, an output corresponding to the acceleration is obtained.

  The switches 150 a to 150 c are provided between the gyro sensor 1 and the CV conversion circuits 31 and 32 in the angular velocity detection circuit 30 and between the gyro sensor 1 and the CV conversion circuit 41 in the acceleration detection circuit 40. It has been.

  The time division switching circuit 151 is for controlling on / off of these switches 150a to 150c. Specifically, the time division switching circuit 151 switches between a period for obtaining a gyro output and a period for performing acceleration detection at a predetermined timing (for example, every predetermined time interval). This is done by sending a drive signal to 150c. That is, the time division switching circuit 151 turns on the switches 150a and 150b and turns off the switch 150c during a period for obtaining the gyro output, and turns off the switches 150a and 150b and turns on the switch 150c during the period for obtaining the acceleration output. A drive signal is output.

  In such a sensor circuit 110 of the gyro sensor 1, it is possible to obtain not only a gyro output but also an acceleration output at the same time. Therefore, basically, the acceleration output is also detected while obtaining the G sensor output, and when the acceleration output is generated, it is fed back to the drive voltage generation circuit 121 and the drive voltage generated by the drive voltage generation circuit 121 is generated. It is possible to cancel the acceleration output generated by the gyro sensor 1 by correcting.

  For example, the drive voltage generation circuit 121 generates, for each electrode 30c, 40c, a value A ± B obtained by adding a constant voltage that is a direct current component and an amplitude voltage that is an alternating current component as a drive voltage. Although driving is performed, the acceleration output of the gyro sensor 1 is canceled by changing the magnitude of the DC component or AC component in the driving voltage. At this time, based on the acceleration output transmitted from the CV conversion circuit 141, whether the magnitude of the direct current component or alternating current component in the drive voltage is increased or decreased so that the acceleration output of the gyro sensor 1 can be canceled. It is supposed to change.

  Next, the operation of the gyro sensor configured as described above will be described. FIG. 4 is a diagram showing a driving voltage application state in the gyro sensor, and the operation of the gyro sensor will be described with reference to this figure.

  First, a drive voltage is generated from the drive voltage generation circuit 121. At this time, as the drive voltage, for example, a voltage having the same magnitude as that of the left and right vibrators 3 and 4 and having alternating-phase AC components is used.

  Specifically, the gyro sensor 1 of this embodiment is driven by applying a desired driving voltage to the driving pad 30c to which the driving fixed electrode 30 is electrically connected. That is, as shown in FIG. 4, of the four driving fixed electrodes 30 in the left vibrator 3, two of the four driving fixed electrodes 30 positioned on the left half side of the drawing and of the four driving fixed electrodes 40 in the right vibrator 4. A ± B [V] is applied as the first voltage from the first power supply 121 a provided in the drive voltage generation circuit 121 to the two located on the right half side of the drawing. Also, two of the four driving fixed electrodes 30 in the left vibrator 3 are positioned on the right half side of the paper, and two of the four driving fixed electrodes 40 of the right vibrator 4 are positioned on the left half of the paper surface. On the other hand, a voltage of C ± D [V] is applied as the second voltage from the second power supply 121b provided in the drive voltage generation circuit 121.

  Here, A ± B [V] as the first voltage and C ± D [V] as the second voltage are AC components that periodically change with respect to the constant voltages A and C that are DC components. It means a voltage value obtained by adding or subtracting voltages B and D. However, the sign of ± of the voltage B that is an AC component and the sign of ± of the voltage D that is an AC component are in a reciprocal relationship, and the voltages are opposite to each other with a period shifted by 180 degrees. In this state, a gyro output is obtained.

  That is, when the switches 150a and 150b are turned on and the switch 150c is turned off based on the drive signal of the time division switching circuit 151, the angular velocity detection circuit 130 uses a pair of CV conversion circuits 131 and 132 to generate a pair of signals. The angular velocity detection signals output from the vibrators 3 and 4 are converted into voltages. Next, when the differential amplifier circuit 133 generates a differential output of the angular velocity detection signal whose voltage is changed in each of the CV conversion circuits 131 and 132, the synchronous detection circuit 134 adjusts the phase adjusted by the phase shifter 123. Based on the above, a component synchronized with the frequency fd is passed from the differential output of the differential amplifier circuit 133.

  Subsequently, a component having a predetermined frequency or less is extracted from the signal after passing through the synchronous detection circuit 134 by the LPF 135, and the output offset and sensitivity included in the signal after passing through the LPF 135 by the zero point / sensitivity temperature special adjustment circuit 136. Is adjusted. Thereby, a gyro output is obtained.

  Next, the switches 150a and 150b are turned off and the switch 150c is turned on at a predetermined timing based on the drive signal of the time division switching circuit 151. Thereby, instead of the gyro output of the angular velocity detection circuit 130, the acceleration detection circuit 140 performs acceleration detection. At this time, if acceleration is generated, the acceleration output is input to the drive voltage generation circuit 121 via the CV conversion circuit 141. As a result, the drive signal generation circuit 121 has a DC component or an AC component in the first voltage A ± B [V] or the second voltage C ± D [V] based on the signal input from the CV conversion circuit 141. Is increased / decreased and output to the gyro sensor 1.

  By doing in this way, the acceleration output of the gyro sensor 1 can be canceled, and it is possible to suppress the gyro output from being affected by the acceleration.

  As described above, in the sensor circuit 110 of the gyro sensor 1 of the present embodiment, when the gyro output is obtained and when the acceleration is detected are switched by the switches 150a to 150c and the time division switching circuit 151, and the gyro sensor 1 is accelerated. Whether or not an output is generated is detected. When the acceleration output is detected, the drive voltage generated by the drive voltage generation circuit 121 is corrected based on the detected acceleration output, and the acceleration output is canceled with respect to the gyro sensor 1. As a result, the acceleration output of the gyro sensor 1 can be canceled, and it can be prevented that the sensor output in which the angular velocity is generated although the angular velocity is not generated is generated.

(Other embodiments)
In each of the above embodiments, a signal corresponding to the acceleration output of the gyro sensor 1 is transmitted to the drive voltage generation circuit 121 through the CV conversion circuit 141. However, among the chips on which the gyro sensor 1 is formed, An electrode is added in the vicinity of the fixed electrode 37 and the movable electrode 38 for detecting the angular velocity in the vibrators 3 and 4, and an acceleration canceling voltage is applied to the electrodes, whereby each electrode 37 and 38 for detecting the angular velocity is applied. It is also possible to correct the drive voltage being applied to and cancel the acceleration.

It is a schematic diagram of the gyro sensor in 1st Embodiment of this invention. It is AA sectional drawing of the gyro sensor shown in FIG. FIG. 3 is a diagram showing a block configuration of a sensor circuit 110. It is the schematic diagram which showed the mode of the application of the drive voltage in the gyro sensor shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Gyro sensor, 2 ... Support substrate, 3 ... Left vibrator, 4 ... Right vibrator, 30, 40 ... Driving fixed electrode, 31, 41 ... Driving movable electrode, 32, 42 ... Vibration detection Fixed electrode, 33, 43 ... movable electrode for vibration detection, 34, 44 ... weight, 35, 45 ... detection beam, 36, 46 ... drive beam, 37, 47 ... fixed electrode for angular velocity detection, 38, 48 ... Movable electrodes for detecting angular velocity, 39, 49... Frame portion 39, 20... Driving circuit, 130... Angular velocity detecting circuit, 131, 132. ... LPF, 136 ... 0 point / sensitivity temperature special adjustment circuit, 140 ... acceleration detection circuit, 141 ... CV conversion circuit, 150a to 150c ... switch, 151 ... time division switching circuit.

Claims (4)

A support substrate (2);
On the support substrate (2), the movable electrode for driving (31) is formed so as to be supported by the support substrate (2) and can be displaced in the horizontal direction with respect to the substrate surface of the support substrate (2). , 41) and a movable part (31, 34, 35, 36, 38, 41, 44, 45, 46, 48) having a movable electrode (38, 48) for detecting angular velocity, and on the support substrate (2) The fixed electrode (30, 40) for driving, which is fixedly supported by the support substrate (2) and faces the movable electrode (31, 41) for driving, and the movable electrode (38) for detecting the angular velocity. , 48) and a fixed part (30, 38, 40, 48) having a fixed electrode (37, 47) for angular velocity detection facing the vibrator (3, 4),
By applying a driving voltage between the driving fixed electrode (30, 40) and the driving movable electrode (31, 41) in the vibrator (3, 4), at least one of the movable parts. The portion (31, 34, 41, 44) is vibrated in one direction parallel to the substrate surface of the support substrate (2),
When an angular velocity is applied to at least a part of the movable part (31, 34, 41, 44), at least a part of the movable part (31, 34, 41, 41) is generated by the Coriolis force generated by the angular speed. 44) is vibrated in one direction perpendicular to the vibration direction, thereby changing the capacitance formed between the movable electrodes (38, 48) and the fixed electrodes (37, 47) for detecting the angular velocity. An angular velocity sensor configured to generate a gyro output corresponding to the angular velocity based on a change in capacity,
A signal corresponding to a change in capacitance formed between the movable electrode (38, 48) for detecting the angular velocity and the fixed electrode (37, 47) is used as an angular velocity detection signal, and the angular velocity detection signal is subjected to signal processing. An angular velocity detection circuit (130) for obtaining the gyro output;
A signal corresponding to a change in capacitance formed between the movable electrode (38, 48) for detecting the angular velocity and the fixed electrode (37, 47) is used as an acceleration detection signal, and the acceleration detection signal is subjected to signal processing. An acceleration detection circuit (140) for obtaining an acceleration output;
A signal indicating a change in capacitance formed between the movable electrode (38, 48) for detecting the angular velocity and the fixed electrode (37, 47) is transmitted to the angular velocity detecting circuit (130), or the acceleration detecting circuit ( 140) switches (150a to 150c) and a switching circuit (151) for switching whether to switch to
Based on the acceleration output obtained by the acceleration detection circuit (140), the driving voltage to be applied between the driving fixed electrode (30, 40) and the driving movable electrode (31, 41). A sensor circuit of a gyro sensor that corrects and cancels the acceleration. The vibrator (3, 4) includes a pair of left and right vibrators (3, 4),
Both the left vibrator (3) and the right vibrator (4) are configured in a bilaterally symmetric structure in which the constituent elements of the left and right vibrators (3, 4) are symmetrical between the left half and the right half. And
By applying the driving voltage between the driving fixed electrode (30, 40) and the driving movable electrode (31, 41) in each of the left and right vibrators (3, 4), the movable part The at least one part (31, 34, 41, 44) is configured to vibrate in one direction parallel to the substrate surface of the support substrate (2). Gyro sensor sensor circuit. The sensor circuit of the gyro sensor according to claim 1, wherein the switching circuit is a time division switching circuit (151) for controlling on / off of the switches (150a to 150c) at a predetermined cycle. . In addition to the driving pads (30c, 40c) for applying the driving voltage, a voltage corresponding to the acceleration output obtained by the acceleration detection circuit (140) is applied to the support substrate (2). A pad is provided, and a voltage corresponding to the acceleration output is applied to the pad, thereby applying between the fixed electrode (30, 40) for driving and the movable electrode (31, 41) for driving. The gyro sensor sensor circuit according to claim 1, wherein the driving voltage is corrected to cancel the acceleration.

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