JP4830488B2 - Angular velocity sensor - Google Patents

Angular velocity sensor Download PDF

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JP4830488B2
JP4830488B2 JP2005377940A JP2005377940A JP4830488B2 JP 4830488 B2 JP4830488 B2 JP 4830488B2 JP 2005377940 A JP2005377940 A JP 2005377940A JP 2005377940 A JP2005377940 A JP 2005377940A JP 4830488 B2 JP4830488 B2 JP 4830488B2
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circuit
electrode
detection
system circuit
level adjustment
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JP2007178299A (en
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勲 服部
啓介 黒田
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Panasonic Corp
Panasonic Holdings Corp
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Panasonic Corp
Matsushita Electric Industrial Co Ltd
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Description

本発明は、駆動系及び検出系電線の断線を同時に検出することが可能な角速度センサに関するものである。   The present invention relates to an angular velocity sensor capable of simultaneously detecting disconnection of a drive system and a detection system electric wire.

角速度センサは振動素子にドライブ振動を与える励振部と、振動体の振動レベルを検出する振動検出部と、入力角速度に応じて生ずるコリオリ振動を検出する少なくとも２つのコリオリ検出部とを有する素子部と、前記振動検出部からの信号を入力とし前記励振部への信号を出力する駆動系回路と、前記コリオリ検出部からの信号を入力とする検出形回路を有する回路部によって構成されている。そして、従来技術としてセンサの信頼性を確保するという意味で前記振動検出部上の検出電極と前記検出電極に接続された検出系回路との接続ラインの断線を検出するというものがある。なお、この出願の発明に関連する先行技術文献情報としては、例えば、特許文献１が知られている。
特開２０００−１４６５９０号公報 The angular velocity sensor includes an excitation unit that applies drive vibration to the vibration element, a vibration detection unit that detects a vibration level of the vibrating body, and an element unit that includes at least two Coriolis detection units that detect Coriolis vibration generated according to the input angular velocity. The driving unit circuit that receives the signal from the vibration detection unit and outputs the signal to the excitation unit, and the circuit unit that includes the detection circuit that receives the signal from the Coriolis detection unit. As a conventional technique, there is one in which disconnection of a connection line between a detection electrode on the vibration detection unit and a detection system circuit connected to the detection electrode is detected in order to ensure the reliability of the sensor. As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2000-146590 A

ところが、上記従来技術では検出電極と前記検出電極に接続された検出系回路との接続ラインの断線は検出することが可能であるが、振動検出部上のモニタ電極と前記モニタ電極に接続された駆動系回路との接続ラインの断線を検出することは困難でありセンサの信頼性を確保する妨げとなっていた。   However, although the disconnection of the connection line between the detection electrode and the detection system circuit connected to the detection electrode can be detected in the above prior art, it is connected to the monitor electrode on the vibration detection unit and the monitor electrode. It is difficult to detect the disconnection of the connection line with the drive system circuit, which has been an obstacle to ensuring the reliability of the sensor.

本発明は、上記従来の問題点を解決するもので駆動系及び検出系電線の断線を同時に検出できる機能を有する角速度センサを提供することを目的とする。   SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and to provide an angular velocity sensor having a function capable of simultaneously detecting disconnection of a drive system and a detection system electric wire.

上記目的を達成するために、本発明は以下の構成を有する。   In order to achieve the above object, the present invention has the following configuration.

本発明の請求項１に記載の角速度センサは、振動素子と、駆動系回路と、検出系回路と、レベル監視回路と、を備えた角速度センサであって、前記振動素子は、駆動電極、モニタ電極、検出電極の上部電極を有し、前記駆動電極、モニタ電極、検出電極はそれぞれ下部電極、圧電薄膜及び上部電極がこの順に積層形成されており、前記駆動系回路は、前記モニタ電極の上部電極に接続されるとともに電流・電圧変換を行う第１のレベル調整回路と、この第１のレベル調整回路の出力側に接続された振動制御回路と、この振動制御回路の出力側に接続されるとともに前記駆動電極の上部電極に接続された駆動回路を含み、前記検出系回路は、前記検出電極の上部電極に接続されるとともに、電流・電圧変換を行う第２のレベル調整回路と、この第２のレベル調整回路の出力側に接続された検出回路を含み、前記レベル監視回路は、前記第１のレベル調整回路の出力側及び前記第２のレベル調整回路の出力側に接続されており、前記下部電極へ入力信号を与えることにより、前記下部電極と前記上部電極間に発生する容量を介してモニタ電極に接続された駆動系回路及び検出電極に接続された検出系回路に電流が流れ、前記レベル監視回路は、第１のレベル調整回路から出力される信号の電圧を第１の閾値と比較することにより前記駆動系回路の断線を検出し、第２のレベル調整回路から出力される信号の電圧を第１の閾値と比較することにより前記検出系回路の断線を検出するよう構成する。この構成により、駆動系及び検出系電線の断線を同時に検出することができる。 An angular velocity sensor according to claim 1 of the present invention is an angular velocity sensor including a vibration element, a drive system circuit , a detection system circuit, and a level monitoring circuit, wherein the vibration element includes a drive electrode, a monitor The drive electrode, the monitor electrode, and the detection electrode are each formed by laminating a lower electrode, a piezoelectric thin film, and an upper electrode in this order, and the drive system circuit is arranged above the monitor electrode . A first level adjustment circuit that is connected to the electrode and performs current / voltage conversion, a vibration control circuit that is connected to an output side of the first level adjustment circuit, and an output side of the vibration control circuit wherein the connected drive circuits to the upper electrode of the driving electrodes with the detection system circuit is connected to the upper electrode of the detection electrode, and the second level adjusting circuit for performing current-voltage conversion, this A level detection circuit connected to an output side of the first level adjustment circuit and an output side of the second level adjustment circuit; By applying an input signal to the lower electrode, a current flows through a drive system circuit connected to the monitor electrode and a detection system circuit connected to the detection electrode via a capacitance generated between the lower electrode and the upper electrode, The level monitoring circuit detects disconnection of the drive system circuit by comparing the voltage of the signal output from the first level adjustment circuit with a first threshold, and outputs the signal output from the second level adjustment circuit. The disconnection of the detection system circuit is detected by comparing the first voltage with a first threshold value. With this configuration, disconnection of the drive system and the detection system electric wire can be detected simultaneously.

本発明の請求項２に記載の発明は、断線検出に用いられる入力信号として、センサに搭載される回路内の内部発振クロックを用いることにより、振動素子と駆動系回路及び検出系回路間の断線を検出するというものであり、別途入力信号を生成することなく電線の断線を検出することができるという作用を有する。   According to the second aspect of the present invention, the internal oscillation clock in the circuit mounted on the sensor is used as an input signal used for disconnection detection, whereby the disconnection between the vibration element, the drive system circuit, and the detection system circuit is performed. This has the effect of detecting the disconnection of the electric wire without generating a separate input signal.

また、レベル調整回路に含まれる電流・電圧変換回路のゲインが設定可能な回路構成とすることにより、検出系の電線の断線を検出することが可能となる。   Further, by using a circuit configuration in which the gain of the current / voltage conversion circuit included in the level adjustment circuit can be set, it is possible to detect the disconnection of the detection system wires.

これらの構成により駆動系及び検出系電線の断線検出を同時に行うことが可能となり、車両制御やエアバックシステム等の高度の信頼性が要求されるアプリケーションに対応した角速度センサを提供できる。   With these configurations, it is possible to simultaneously detect the disconnection of the drive system and the detection system electric wire, and it is possible to provide an angular velocity sensor corresponding to an application that requires a high degree of reliability, such as vehicle control and an airbag system.

以下、本発明の実施の形態１における電線の断線検出について図１〜図４を用いて図面を参照しながら説明する。   Hereinafter, wire breakage detection in Embodiment 1 of the present invention will be described with reference to FIGS.

（実施の形態１）
図１は本発明の一実施の形態における角速度センサブロック図、図２は図１におけるＡ−Ａ断面図、図３は断線検出時の本発明の角速度センサブロック図、図４は振動素子及びレベル調整回路を含めた等価回路図である。 (Embodiment 1)
1 is a block diagram of an angular velocity sensor according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, FIG. 3 is a block diagram of an angular velocity sensor according to the present invention when a disconnection is detected, and FIG. It is an equivalent circuit diagram including an adjustment circuit.

図１において、本発明における角速度センサは、振動素子１と、レベル調整回路２ａ、振動制御回路２ｂ、駆動回路２ｃを含む駆動系回路２と、レベル調整回路３ａ及び検出回路３ｂを含む検出系回路３より構成され、前記振動素子１上には駆動電極４、５とモニタ電極６と、検出電極７、８と、基準電圧が印加される下部電極９が存在する。前記モニタ電極６と前記駆動系回路２の入力部が接続され、前記駆動回路２の出力部と前記駆動電極４、５が接続され、前記検出電極７、８と前記検出系回路３の入力部が接続される。なお、振動素子１上の電極の形状及び配置に関して図１では模式図としている。また、回路部には回路の内部クロックを生成するクロック発振回路１１と、前記駆動系回路２及び前記検出系回路３の電圧レベルを監視するレベル監視回路１２が存在する。そして、角速度検出時には前記振動制御回路２ｂは切り替え部１０を介して前記下部電極９に基準電圧を供給している。前記下部電極９と切り替え部１０が接続され、前記切り替え部１０と前記クロック発振回路１１及び前記振動制御回路２ｂが接続されている。ここで、振動素子の動作原理と、角速度成分の検出原理と、回路構成及び動作原理に関する説明は省略するものとする。   In FIG. 1, an angular velocity sensor according to the present invention includes a vibration element 1, a drive circuit 2 including a level adjustment circuit 2a, a vibration control circuit 2b, and a drive circuit 2c, and a detection system circuit including a level adjustment circuit 3a and a detection circuit 3b. 3, the drive electrodes 4 and 5, the monitor electrode 6, the detection electrodes 7 and 8, and the lower electrode 9 to which a reference voltage is applied exist on the vibration element 1. The monitor electrode 6 and the input part of the drive system circuit 2 are connected, the output part of the drive circuit 2 and the drive electrodes 4 and 5 are connected, the detection electrodes 7 and 8 and the input part of the detection system circuit 3 Is connected. Note that the shape and arrangement of the electrodes on the vibration element 1 are schematically shown in FIG. The circuit section includes a clock oscillation circuit 11 that generates an internal clock of the circuit, and a level monitoring circuit 12 that monitors the voltage levels of the drive system circuit 2 and the detection system circuit 3. When the angular velocity is detected, the vibration control circuit 2 b supplies a reference voltage to the lower electrode 9 via the switching unit 10. The lower electrode 9 and the switching unit 10 are connected, and the switching unit 10 is connected to the clock oscillation circuit 11 and the vibration control circuit 2b. Here, descriptions of the operating principle of the vibration element, the detection principle of the angular velocity component, the circuit configuration, and the operating principle are omitted.

図２において、振動素子１のアーム１４上に下部電極４０、圧電薄膜１３及び上部電極４１が積層形成されている。角速度検出時には、基準電圧供給部１５に、駆動系回路２内の振動制御回路２ｂより基準電圧が供給される。そして、前記下部電極４０と前記上部電極４１間にはＰ（ピコ）オーダーの電極間容量１６が発生している。つまり、前記振動素子１を、インピーダンスを持つ回路素子と考えた場合、基準電圧をＧＮＤとして回路的にループが発生していると考えることができる。そこで、本実施の形態では、この回路ループを利用して基準電圧供給部１５に回路の内部クロックを与え、前記電極間容量１６を介して流れる電流Ｉを前記上部電極４１と接続された検出系回路２及び駆動系回路３を含む回路部にて電圧レベルに変換し、レベル監視回路１２を用いてレベル監視を行う。本実施の形態で用いる内部クロックは回路内のＳＣＦに用いられるものであり、断線検出に入力信号として用いる場合は分周して下部電極４０に与えるものとする。これにより、別途入力信号を生成する必要がなく断線検出を行うことが可能となる。   In FIG. 2, a lower electrode 40, a piezoelectric thin film 13, and an upper electrode 41 are stacked on the arm 14 of the vibration element 1. At the time of angular velocity detection, the reference voltage is supplied to the reference voltage supply unit 15 from the vibration control circuit 2b in the drive system circuit 2. An interelectrode capacitance 16 of P (pico) order is generated between the lower electrode 40 and the upper electrode 41. That is, when the vibration element 1 is considered as a circuit element having an impedance, it can be considered that a loop is generated in a circuit with the reference voltage as GND. Therefore, in the present embodiment, an internal clock of the circuit is supplied to the reference voltage supply unit 15 using this circuit loop, and the current I flowing through the interelectrode capacitance 16 is connected to the upper electrode 41. The voltage is converted into a voltage level by a circuit unit including the circuit 2 and the drive system circuit 3, and level monitoring is performed using the level monitoring circuit 12. The internal clock used in the present embodiment is used for the SCF in the circuit, and when used as an input signal for disconnection detection, the frequency is divided and given to the lower electrode 40. As a result, it is possible to detect disconnection without generating a separate input signal.

断線検出時には図３に示すように、切り替え部１０とクロック発振回路１１が接続され、内部クロックを分周した入力信号が下部電極９に入力され、モニタ電極６と下部電極９間の容量、検出電極７、８と下部電極９間の容量、駆動電極４、５と下部電極９間の容量を介して回路部に電流が流れる。ところが、前記駆動電極４、５に関しては駆動系回路２の出力部と接続されているため、前記駆動系回路２の出力部に入力信号により発生する電流が注入されることになる。これにより、駆動系回路２の故障を招く恐れがあるため、切り替え部１０の動作と連動して断線検出時は振動素子１の駆動を停止させ、駆動系回路２の出力部と駆動電極間４、５がＨｉｇｈインピーダンスになるように回路を構成する。   When disconnection is detected, as shown in FIG. 3, the switching unit 10 and the clock oscillation circuit 11 are connected, and an input signal obtained by dividing the internal clock is input to the lower electrode 9, and the capacitance between the monitor electrode 6 and the lower electrode 9 is detected. A current flows through the circuit portion via the capacitance between the electrodes 7 and 8 and the lower electrode 9 and the capacitance between the drive electrodes 4 and 5 and the lower electrode 9. However, since the drive electrodes 4 and 5 are connected to the output part of the drive system circuit 2, the current generated by the input signal is injected into the output part of the drive system circuit 2. This may cause a failure of the drive system circuit 2, and therefore, when the disconnection is detected in conjunction with the operation of the switching unit 10, the drive of the vibration element 1 is stopped, and the distance between the output unit and the drive electrode 4 of the drive system circuit 2. The circuit is configured so that 5 has a high impedance.

電線の断線を検出するために、本実施の形態では図４に示すような駆動系回路２におけるレベル調整回路２８と検出系回路３におけるレベル調整回路２９を用いる。ここでは、駆動系回路２におけるレベル調整回路２８について説明を行う。駆動系回路２におけるレベル調整回路２８は、可変抵抗２６を帰還抵抗とし、アナログＧＮＤ２４に基準電圧が印加された電流・電圧変換回路３０により構成されている。そして、駆動系回路２におけるレベル調整回路出力２０とレベル監視回路１２が接続され、下部電極１７とモニタ電極１８の間に発生する電極間容量２２が駆動系回路２におけるレベル調整回路２８の入力部に入力抵抗として接続されている。ここでは、下部電極１７より入力される電流を電流・電圧変換回路３０により電圧に変換し、駆動系回路２におけるレベル調整回路出力をレベル監視回路１２にて監視し断線を検出する。レベル監視回路には閾値が設けられており、電線の断線が発生しているかどうかを判断する。電流・電圧変換回路３０の帰還抵抗が可変抵抗２６となっているのは電流・電圧変換回路３０のゲインを調整することにより、レベル調整回路出力の出力レベルを調整するためである。電流・電圧変換回路３０のゲインは、可変抵抗２６と振動素子１の電極間容量２２の比で決定される。そのため、仮に電流・電圧変換回路３０の帰還抵抗に可変抵抗でないものを用いた場合、振動素子１の電極間容量２２はばらつきがあるため、各角速度センサによって電流・電圧変換回路３０のゲインが異なり、例えレベル監視回路１２に閾値を設け電圧レベルを監視したとしても、電線の断線を正確に検出することができるとは限らない。本実施の形態では、電流・電圧変換回路３０のゲインが設定可能な回路構成にすることにより、正確に駆動系の電線の断線を検出することが可能となる。   In this embodiment, a level adjustment circuit 28 in the drive system circuit 2 and a level adjustment circuit 29 in the detection system circuit 3 as shown in FIG. Here, the level adjustment circuit 28 in the drive system circuit 2 will be described. The level adjustment circuit 28 in the drive system circuit 2 includes a current / voltage conversion circuit 30 in which the variable resistor 26 is used as a feedback resistor and a reference voltage is applied to the analog GND 24. The level adjustment circuit output 20 and the level monitoring circuit 12 in the drive system circuit 2 are connected, and the interelectrode capacitance 22 generated between the lower electrode 17 and the monitor electrode 18 is an input part of the level adjustment circuit 28 in the drive system circuit 2. Connected as an input resistor. Here, the current input from the lower electrode 17 is converted to a voltage by the current / voltage conversion circuit 30, and the level adjustment circuit output in the drive system circuit 2 is monitored by the level monitoring circuit 12 to detect disconnection. The level monitoring circuit is provided with a threshold value, and it is determined whether or not the wire is disconnected. The reason why the feedback resistor of the current / voltage conversion circuit 30 is the variable resistor 26 is to adjust the output level of the level adjustment circuit output by adjusting the gain of the current / voltage conversion circuit 30. The gain of the current / voltage conversion circuit 30 is determined by the ratio of the variable resistor 26 and the interelectrode capacitance 22 of the vibration element 1. Therefore, if the feedback resistor of the current / voltage conversion circuit 30 is not a variable resistor, the interelectrode capacitance 22 of the vibration element 1 varies, and the gain of the current / voltage conversion circuit 30 differs depending on each angular velocity sensor. Even if a threshold value is provided in the level monitoring circuit 12 and the voltage level is monitored, it is not always possible to accurately detect the disconnection of the electric wire. In the present embodiment, the circuit configuration in which the gain of the current / voltage conversion circuit 30 can be set makes it possible to accurately detect the disconnection of the electric wires of the drive system.

一方、検出系回路３におけるレベル調整回路２９について説明を行う。検出系回路３におけるレベル調整回路２９は、可変抵抗２７を帰還抵抗とし、アナログＧＮＤ２５に基準電圧が印加された電流・電圧変換回路３１により構成されている。そして、検出系回路３におけるレベル調整回路２１とレベル監視回路１２が接続され、下部電極１７と検出電極１９の間に発生する電極間容量２３が検出系回路３におけるレベル調整回路２９の入力部に入力抵抗として接続されている。ここでは、下部電極１７より入力される電流を電流・電圧変換回路３１により電圧に変換し、検出系回路３におけるレベル調整回路出力をレベル監視回路１２にて監視し断線を検出する。レベル監視回路１２には閾値が設けられており、電線の断線が発生しているかどうかを判断する。電流・電圧変換回路３１の帰還抵抗が可変抵抗２７となっているのは電流・電圧変換回路３１のゲインを調整することにより、レベル調整回路出力の出力レベルを調整するためである。電流・電圧変換回路３１のゲインは、可変抵抗２７と振動素子１の電極間容量２３の比で決定される。そのため、仮に電流・電圧変換回路３１の帰還抵抗に可変抵抗でないものを用いた場合、振動素子１の電極間容量２３はばらつきがあるため、各角速度センサによって電流・電圧変換回路３１のゲインが異なり、例えレベル監視回路１２に閾値を設け電圧レベルを監視したとしても、電線の断線を正確に検出することができるとは限らない。本実施の形態では、電流・電圧変換回路３１のゲインが設定可能な回路構成にすることにより、検出系の電線の断線を検出することができる。   On the other hand, the level adjustment circuit 29 in the detection system circuit 3 will be described. The level adjustment circuit 29 in the detection system circuit 3 includes a current / voltage conversion circuit 31 in which the variable resistor 27 is used as a feedback resistor and a reference voltage is applied to the analog GND 25. Then, the level adjustment circuit 21 and the level monitoring circuit 12 in the detection system circuit 3 are connected, and the interelectrode capacitance 23 generated between the lower electrode 17 and the detection electrode 19 is input to the level adjustment circuit 29 in the detection system circuit 3. Connected as input resistance. Here, the current input from the lower electrode 17 is converted into a voltage by the current / voltage conversion circuit 31 and the level adjustment circuit output in the detection system circuit 3 is monitored by the level monitoring circuit 12 to detect disconnection. The level monitoring circuit 12 is provided with a threshold value, and it is determined whether or not an electric wire is disconnected. The reason why the feedback resistor of the current / voltage conversion circuit 31 is the variable resistor 27 is to adjust the output level of the level adjustment circuit output by adjusting the gain of the current / voltage conversion circuit 31. The gain of the current / voltage conversion circuit 31 is determined by the ratio of the variable resistor 27 and the interelectrode capacitance 23 of the vibration element 1. For this reason, if the feedback resistor of the current / voltage conversion circuit 31 is not a variable resistor, the interelectrode capacitance 23 of the vibration element 1 varies, so that the gain of the current / voltage conversion circuit 31 differs depending on each angular velocity sensor. Even if a threshold value is provided in the level monitoring circuit 12 and the voltage level is monitored, it is not always possible to accurately detect the disconnection of the electric wire. In the present embodiment, by using a circuit configuration in which the gain of the current / voltage conversion circuit 31 can be set, it is possible to detect a disconnection of the electric wire of the detection system.

そのため、上記実施の形態により、駆動系及び検出系電線の断線検出を行うことが可能となる。   Therefore, according to the above-described embodiment, it is possible to detect disconnection of the drive system and the detection system electric wire.

本発明の角速度センサは、駆動系及び検出系電線の断線検出を同時に行うことが可能であり、安全性を考慮した車両制御システムや、車体横転時に展開するロールオーバーエアバックシステム等、高度の信頼性が要求されるアプリケーションにおいて有用である。   The angular velocity sensor of the present invention can simultaneously detect the disconnection of the drive system and the detection system electric wire, and is highly reliable, such as a vehicle control system considering safety and a rollover airbag system deployed when the vehicle rolls over. This is useful in applications that require performance.

本発明の一実施の形態における角速度センサのブロック図The block diagram of the angular velocity sensor in one embodiment of this invention 図１におけるＡ−Ａ断面図AA sectional view in FIG. 断線検出時の本発明の角速度センサのブロック図Block diagram of the angular velocity sensor of the present invention when disconnection is detected 振動素子及びレベル調整回路を含めた等価回路図Equivalent circuit diagram including vibration element and level adjustment circuit

符号の説明Explanation of symbols

１ 振動素子
２ 駆動系回路
３ 検出系回路
４、５ 駆動電極
６、１８ モニタ電極
７、８、１９ 検出電極
９、１２、１７ 下部電極
１０ 切り替え部
１１ 上部電極
１３ 圧電薄膜
１４ 振動素子１のアーム
１５ 基準電圧供給部
１６ 電極間容量
２０ 駆動系回路２におけるレベル調整回路出力
２１ 検出系回路３におけるレベル調整回路出力
２２、２３ 電極間容量
２４、２５ アナログＧＮＤ
２６、２７ 可変抵抗
２８ 駆動系回路２におけるレベル調整回路
２９ 検出系回路３におけるレベル調整回路 DESCRIPTION OF SYMBOLS 1 Vibration element 2 Drive system circuit 3 Detection system circuit 4, 5 Drive electrode 6, 18 Monitor electrode 7, 8, 19 Detection electrode 9, 12, 17 Lower electrode 10 Switching part 11 Upper electrode 13 Piezoelectric thin film 14 Arm of vibration element 1 DESCRIPTION OF SYMBOLS 15 Reference voltage supply part 16 Electrode capacity | capacitance 20 Level adjustment circuit output in the drive system circuit 2 21 Level adjustment circuit output in the detection system circuit 22, 23 Interelectrode capacity | capacitance 24, 25 Analog GND
26, 27 Variable resistance 28 Level adjustment circuit in drive system circuit 2 29 Level adjustment circuit in detection system circuit 3

Claims (2)

振動素子と、駆動系回路と、検出系回路と、レベル監視回路と、を備えた角速度センサであって、
前記振動素子は、駆動電極、モニタ電極、検出電極の上部電極を有し、
前記駆動電極、モニタ電極、検出電極はそれぞれ下部電極、圧電薄膜及び上部電極がこの順に積層形成されており、
前記駆動系回路は、前記モニタ電極の上部電極に接続されるとともに電流・電圧変換を行う第１のレベル調整回路と、この第１のレベル調整回路の出力側に接続された振動制御回路と、この振動制御回路の出力側に接続されるとともに前記駆動電極の上部電極に接続された駆動回路を含み、
前記検出系回路は、前記検出電極の上部電極に接続されるとともに、電流・電圧変換を行う第２のレベル調整回路と、この第２のレベル調整回路の出力側に接続された検出回路を含み、
前記レベル監視回路は、前記第１のレベル調整回路の出力側及び前記第２のレベル調整回路の出力側に接続されており、
前記下部電極へ入力信号を与えることにより、前記下部電極と前記上部電極間に発生する容量を介してモニタ電極に接続された駆動系回路及び検出電極に接続された検出系回路に電流が流れ、
前記レベル監視回路は、第１のレベル調整回路から出力される信号の電圧を第１の閾値と比較することにより前記駆動系回路の断線を検出し、第２のレベル調整回路から出力される信号の電圧を第１の閾値と比較することにより前記検出系回路の断線を検出するよう構成した角速度センサ。 An angular velocity sensor including a vibration element, a drive system circuit , a detection system circuit, and a level monitoring circuit,
The vibration element has a drive electrode, a monitor electrode, and an upper electrode of a detection electrode,
The drive electrode, the monitor electrode, and the detection electrode are each formed by laminating a lower electrode, a piezoelectric thin film, and an upper electrode in this order,
The drive system circuit is connected to the upper electrode of the monitor electrode and performs a current / voltage conversion, a vibration control circuit connected to the output side of the first level adjustment circuit, A drive circuit connected to the output side of the vibration control circuit and connected to the upper electrode of the drive electrode;
The detection system circuit includes a second level adjustment circuit that is connected to the upper electrode of the detection electrode , performs current / voltage conversion, and a detection circuit connected to an output side of the second level adjustment circuit. ,
The level monitoring circuit is connected to the output side of the first level adjustment circuit and the output side of the second level adjustment circuit,
By applying an input signal to the lower electrode, a current flows through a drive system circuit connected to the monitor electrode and a detection system circuit connected to the detection electrode via a capacitance generated between the lower electrode and the upper electrode,
The level monitoring circuit detects disconnection of the drive system circuit by comparing the voltage of the signal output from the first level adjustment circuit with a first threshold, and outputs the signal output from the second level adjustment circuit. An angular velocity sensor configured to detect disconnection of the detection system circuit by comparing the voltage of the detection system circuit with a first threshold value. 断線検出に用いられる入力信号として、駆動系回路及び検出系回路を含む回路部の内部発振クロックを用い振動素子の駆動系回路及び検出系回路間の断線を同時に検出するよう構成した請求項１記載の角速度センサ。 2. The disconnection between the drive system circuit of the vibration element and the detection system circuit is simultaneously detected using an internal oscillation clock of a circuit unit including the drive system circuit and the detection system circuit as an input signal used for disconnection detection. Angular velocity sensor.
JP2005377940A 2005-12-28 2005-12-28 Angular velocity sensor Expired - Fee Related JP4830488B2 (en)

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