JPH04109371U - Diagnostic circuit for semiconductor acceleration sensor - Google Patents
Diagnostic circuit for semiconductor acceleration sensorInfo
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- JPH04109371U JPH04109371U JP1967591U JP1967591U JPH04109371U JP H04109371 U JPH04109371 U JP H04109371U JP 1967591 U JP1967591 U JP 1967591U JP 1967591 U JP1967591 U JP 1967591U JP H04109371 U JPH04109371 U JP H04109371U
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- acceleration sensor
- resistors
- diagnostic
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- 230000001133 acceleration Effects 0.000 title claims abstract description 41
- 239000004065 semiconductor Substances 0.000 title claims abstract description 22
- 238000003745 diagnosis Methods 0.000 claims description 13
- 238000010586 diagram Methods 0.000 description 4
- 101000582320 Homo sapiens Neurogenic differentiation factor 6 Proteins 0.000 description 1
- 102100030589 Neurogenic differentiation factor 6 Human genes 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Abstract
(57)【要約】
【目的】 センサ出力に影響を与えることなく，かつ確
実に断線等の故障を検出する。
【構成】 半導体加速度センサは，ピエゾ抵抗素子を用
いた４つの抵抗Ｒ1 ，Ｒ2 ，Ｒ3 ，Ｒ4 で構成したホイ
ートストーンブリッジ回路１を持つ。２つの比較器２１
からなるウインドコンパレータ２２，２３を２個設け
る。各ウインドコンパレータ２２，２３の入力端子Ｐ，
Ｑをそれぞれ，ホイートストーンブリッジ回路１の２つ
のブリッジ端子Ａ，Ｂに接続する。入力端子Ｐ，Ｑ側を
ダミー抵抗Ｒｘを介して接地する。ウインドコンパレー
タ２２，２３は前記Ａ点あるいはＢ点の電位が設定上限
電圧ＶH と設定下限電圧ＶL との間にあるかを監視す
る。その範囲内にあれば断線がないと診断できる。
(57) [Summary] [Purpose] To reliably detect failures such as disconnections without affecting sensor output. [Structure] The semiconductor acceleration sensor has a Wheatstone bridge circuit 1 composed of four resistors R 1 , R 2 , R 3 , and R 4 using piezoresistive elements. two comparators 21
Two window comparators 22 and 23 are provided. Input terminal P of each window comparator 22, 23,
Q are connected to two bridge terminals A and B of the Wheatstone bridge circuit 1, respectively. The input terminals P and Q sides are grounded via a dummy resistor Rx. Window comparators 22 and 23 monitor whether the potential at point A or point B is between the set upper limit voltage VH and the set lower limit voltage VL. If it is within that range, it can be diagnosed that there is no disconnection.
Description
【０００１】0001
この考案は，例えば自動車に搭載した半導体加速度センサの故障を検出する診 断回路に関する。 This idea can be used, for example, in diagnostics to detect failures in semiconductor acceleration sensors installed in automobiles. Regarding disconnection.
【０００２】0002
従来より，図５に示すように，力が加わると抵抗値が変化する特性を持つピエ ゾ抵抗素子を用いた４つの抵抗Ｒ1 ，Ｒ2 ，Ｒ3 ，Ｒ4 でホイートストーンブリ ッジ回路を構成し，このブリッジ回路１の２つのブリッジ端子Ａ，Ｂを差動増幅 器２に接続してなる半導体加速度センサが知られている。なお，図示例の各抵抗 の抵抗値は等しい（Ｒ1 ＝Ｒ2 ＝Ｒ3 ＝Ｒ4 ）。従来，この種の半導体加速度セ ンサにおける抵抗Ｒ1 ，Ｒ2 ，Ｒ3 ，Ｒ4 の断線等の故障を診断する場合，セン サ出力すなわち差動増幅器２の出力に基づいて診断していた。例えばセンサ駆動 電圧Ｖｉｎを５ｖ（ボルト）とした場合，ブリッジ回路１に断線がなく正常の場 合はセンサ出力は零であるが，ブリッジ回路１の抵抗Ｒ1 の１箇所だけが断線の 場合はＢ点がＧＮＤ電位となってＡ，Ｂ点の電圧差が＋２．５ｖとなり，また， 抵抗Ｒ2 の１箇所だけが断線の場合はＡ，Ｂ点の電圧差が−２．５ｖとなり，ま た，抵抗Ｒ1 とＲ4 の２箇所または抵抗Ｒ3 とＲ2 の２箇所が断線した場合には ，Ａ，Ｂ点の電圧差が＋５ｖまたは−５ｖとなるので，いずれもセンサ出力で断 線を検出できる。しかし，抵抗Ｒ1 とＲ3 の２箇所の断線の場合はＡ点，Ｂ点が ＧＮＤ電位となりＡ，Ｂ点の電圧差が生じないので，センサ出力からは断線を検 出できない。また，抵抗Ｒ2 とＲ4 との２箇所の断線の場合，抵抗Ｒ1 ，Ｒ2 ， Ｒ3 の３箇所の断線の場合，抵抗Ｒ1 ，Ｒ2 ，Ｒ4 の３箇所の断線の場合，抵抗 Ｒ1 ，Ｒ2 ，Ｒ3 ，Ｒ4 の４箇所の断線の場合の各場合には，いずれもＡ，Ｂ点 の少なくとも１箇所は不定となり，断線を検出できない。上述のごとき加速度セ ンサ出力による故障診断の可否の詳細を，ＦＭＥＡ（フェール・モー・エフェク ト・アナリシス：すなわち，故障が起きた場合にどのような現象が起きるかの分 析）の表１の備考の欄に示す。Conventionally, as shown in Figure 5, a Wheatstone bridge circuit has been configured with four resistors R 1 , R 2 , R 3 , and R 4 using piezoresistive elements whose resistance value changes when force is applied. However, a semiconductor acceleration sensor is known in which two bridge terminals A and B of this bridge circuit 1 are connected to a differential amplifier 2. Note that the resistance values of the respective resistors in the illustrated example are equal (R 1 =R 2 =R 3 =R 4 ). Conventionally, when diagnosing a failure such as disconnection of resistors R 1 , R 2 , R 3 , R 4 in this type of semiconductor acceleration sensor, the diagnosis was based on the sensor output, that is, the output of the differential amplifier 2. For example, if the sensor drive voltage Vin is 5V (volts), the sensor output will be zero if the bridge circuit 1 is normal without any disconnection, but if only one location of the resistor R1 of the bridge circuit 1 is disconnected, the sensor output will be B. The point becomes GND potential, and the voltage difference between points A and B becomes +2.5v. Also, if only one point of resistor R2 is disconnected, the voltage difference between points A and B becomes -2.5v, and, If the two resistors R1 and R4 or the two resistors R3 and R2 are disconnected, the voltage difference between points A and B will be +5v or -5v, so the disconnection will be detected by the sensor output. can. However, in the case of a break in the resistors R 1 and R 3 at two locations, points A and B are at GND potential and no voltage difference occurs between points A and B, so the break cannot be detected from the sensor output. In addition, in the case of a disconnection in two places between resistors R 2 and R 4 , in the case of a disconnection in three places in resistors R 1 , R 2 , and R 3 , in the case of a disconnection in three places in resistors R 1 , R 2 , and R 4 . , resistors R 1 , R 2 , R 3 , and R 4 , in each case, at least one of points A and B becomes undefined and the disconnection cannot be detected. Details of whether or not fault diagnosis can be performed using the acceleration sensor output as described above can be found in the remarks column of Table 1 of FMEA (Fail Mor Effect Analysis: Analysis of what phenomena will occur when a fault occurs). Shown below.
【０００３】 ところで，例えば自動車に衝突時の乗員保護のためのエアバッグ装置を設置 する場合，エアバッグ装置の電気回路の一部に，衝突を検知するための装置とし て加速度センサが搭載される。この電気回路において，加速度センサの断線等の 故障を検出する回路を設けた例を図６に示す（特公昭５８−２３２６４号参照） 。この電気回路は，衝撃でオンとなる機械式スイッチを利用した２個の加速度セ ンサ３と４または５と６を並列に接続した二群の検出器を備えている。加速度セ ンサの各群間（加速度センサ３，４の群と加速度センサ５，６の群との間）に， 並列接続の２個の雷管７，８を接続するとともに，各雷管７，８にそれぞれ抵抗 ９，１０を直列に接続している。そして，各加速度センサ３，４，５，６の断線 等を検出するために，差動増幅器１１，電圧比較回路１２，ウインドコンパレー タ１３，ＡＮＤ回路１４を備えている。このエアバッグ装置電気回路において， 電源スイッチ１５の投入状態で装置全体の電源が供給され，一定値以上の大きさ の衝撃（減速度／加速度）が加わって加速度センサ３，４，５，６のいずれかが スイッチオンとなると，雷管７，８に通電が行われて，その結果エアバッグが展 開されて，乗員の保護を行う。0003 By the way, for example, airbag devices are installed in cars to protect occupants in the event of a collision. If a collision is detected, a part of the electrical circuit of the airbag system is equipped with It is equipped with an acceleration sensor. In this electrical circuit, the acceleration sensor may be disconnected, etc. Figure 6 shows an example of a circuit that detects failures (see Japanese Patent Publication No. 58-23264). . This electrical circuit consists of two acceleration sensors using mechanical switches that are turned on by impact. It is equipped with two groups of detectors in which sensors 3 and 4 or 5 and 6 are connected in parallel. Acceleration Between each group of sensors (between the group of acceleration sensors 3 and 4 and the group of acceleration sensors 5 and 6), Two detonators 7 and 8 are connected in parallel, and a resistor is connected to each detonator 7 and 8. 9 and 10 are connected in series. And disconnection of each acceleration sensor 3, 4, 5, 6 In order to detect the 13 and an AND circuit 14. In this airbag device electrical circuit, When the power switch 15 is turned on, power is supplied to the entire device, and the power exceeds a certain value. When an impact (deceleration/acceleration) is applied, any of the acceleration sensors 3, 4, 5, and 6 When the switch is turned on, the detonators 7 and 8 are energized, resulting in the airbag being deployed. It opens to protect the occupants.
【０００４】0004
上記のように，機械式で，かつ，一定大きさを越えたか否かのみを検出する加 速度センサ３，４，５，６を用いる場合の診断回路であれば，回路中に前記の抵 抗９，１０を挿入し，この抵抗９，１０に電流が流れることによる電圧降下を利 用することが可能である。しかし，加速度センサとして，ホイートストーンブリ ッジを構成する４つのピエゾ抵抗素子Ｒ1 ，Ｒ2 ，Ｒ3 ，Ｒ4 用いた上述の図５ の半導体加速度センサを用いる場合，センサー出力はオンかオフかでなく大きさ を持つ出力であるから，上記のごとき抵抗９，１０を回路中に挿入したのではセ ンサー出力を変化させてしまうので，採用できない。As mentioned above, if the diagnostic circuit is mechanical and uses acceleration sensors 3, 4, 5, and 6 that only detect whether or not a certain magnitude has been exceeded, the resistor 9, It is possible to insert the resistors 9 and 10 and utilize the voltage drop caused by current flowing through the resistors 9 and 10. However, when using the semiconductor acceleration sensor shown in Figure 5, which uses the four piezoresistive elements R 1 , R 2 , R 3 , and R 4 forming the Wheatstone bridge, as an acceleration sensor, the sensor output is either on or off. Therefore, inserting the resistors 9 and 10 as described above into the circuit cannot be used because it would change the sensor output.
【０００５】 本考案は上記事情に鑑みてなされたもので，センサ出力に影響を与えることな く，かつ確実に断線等の故障を検出することができる半導体加速度センサの診断 回路を得ることを目的とする。[0005] This invention was developed in view of the above circumstances, and does not affect the sensor output. Diagnosis of semiconductor acceleration sensors that can easily and reliably detect failures such as disconnections The purpose is to obtain a circuit.
【０００６】[0006]
上記課題を解決する本考案は，ピエゾ抵抗素子を用いた４つの抵抗Ｒ1 ，Ｒ2 ，Ｒ3 ，Ｒ4 でホイートストーンブリッジ回路を構成し，このホイートストーン ブリッジ回路の２つのブリッジ端子Ａ，Ｂを差動増幅器に接続してなる半導体加 速度センサの故障を診断する診断回路であって，前記ホイートストーンブリッジ 回路の２つのブリッジ端子Ａ，Ｂにそれぞれ接続される診断入力端子Ｐ，Ｑを持 ち，各診断入力端子と前記各ブリッジ端子Ａ，Ｂとの間をそれぞれダミー抵抗Ｒ ｘを介在させて接地し，前記２つの診断入力端子ごとに，各入力端子から入力さ れるブリッジ端子電圧ＶA ，ＶB と設定上限電圧ＶH および設定下限電圧ＶL とをそれぞれ比較する２つの比較器からなるウインドコンパレータを設けたこと を特徴とする。The present invention, which solves the above problems, configures a Wheatstone bridge circuit with four resistors R 1 , R 2 , R 3 , and R 4 using piezoresistive elements, and connects two bridge terminals of this Wheatstone bridge circuit. A diagnostic circuit for diagnosing a failure of a semiconductor acceleration sensor formed by connecting A and B to a differential amplifier, the diagnostic input terminal P being connected to the two bridge terminals A and B of the Wheatstone bridge circuit, respectively; A dummy resistor Rx is interposed between each diagnostic input terminal and each of the bridge terminals A and B to ground the bridge terminal, and for each of the two diagnostic input terminals, input from each input terminal is connected to the bridge terminal. The present invention is characterized in that a window comparator consisting of two comparators is provided to compare the voltages VA and VB with a set upper limit voltage VH and a set lower limit voltage VL, respectively.
【０００７】 請求項２は，前記ブリッジ端子ＶA ，ＶB と前記ダミ−抵抗分岐部との間に スイッチを設けたことを特徴とする。[0007] Claim 2 provides that between the bridge terminals VA, VB and the dummy resistor branch, It is characterized by the provision of a switch.
【０００８】 請求項３は，前記ダミー抵抗Ｒｘをホイートストーンブリッジの４つの抵抗Ｒ 1 ，Ｒ2 ，Ｒ3 ，Ｒ4 より十分大きくして，常時診断するようにしたことを特徴 とする。[0008] In a third aspect, the dummy resistor Rx is replaced by four resistors R of a Wheatstone bridge. 1 ,R2 ,R3 ,RFour It is characterized by being sufficiently large and capable of constant diagnosis. shall be.
【０００９】[0009]
上記構成において，ブリッジ回路の２つのブリッジ端子Ａ，Ｂの電圧すなわち ブリッジ端子電圧ＶA ，ＶB は，ウインドコンパレータの診断入力端子Ｐ，Ｑ に入力される。ウインドコンパレータは，このブリッジ端子電圧ＶA ，ＶB が 設定上限電圧ＶH と設定下限電圧ＶL との間にあるか否かを監視し，いずれも正 常範囲内すなわち上記ＶH レベルとＶL レベルとの間にあれば断線はないと診断 する。一方または両方が正常範囲外であれば，断線が生じていると診断する。こ の場合，入力端子側をダミー抵抗を介在させて接地したウインドコンパレータに より，ブリッジ回路の２つのブリッジ端子Ａ，Ｂの設定上限電圧および設定下限 電圧を監視するものであるから，ブリッジ回路の４つの抵抗のいずれが断線して も，必ずその断線を検出できる。 In the above configuration, the voltage at the two bridge terminals A and B of the bridge circuit, i.e. The bridge terminal voltages VA and VB are the diagnostic input terminals P and Q of the window comparator. is input. The window comparator has this bridge terminal voltage VA, VB. Monitor whether the voltage is between the set upper limit voltage VH and the set lower limit voltage VL, and check if both are correct. If it is within the normal range, that is, between the above VH level and VL level, it is diagnosed that there is no disconnection. do. If one or both are outside the normal range, a disconnection is diagnosed. child In this case, use a window comparator whose input terminal side is grounded through a dummy resistor. Therefore, the set upper limit voltage and set lower limit of the two bridge terminals A and B of the bridge circuit are Since it monitors the voltage, there is no possibility that any of the four resistors in the bridge circuit may be disconnected. However, the disconnection can always be detected.
【００１０】 請求項２において，ブリッジ端子とダミ−抵抗分岐部との間のスイッチをオフ とすれば，診断回路は加速度センサの出力に全く影響を与えない。0010 In claim 2, the switch between the bridge terminal and the dummy resistor branch is turned off. If so, the diagnostic circuit has no effect on the output of the acceleration sensor.
【００１１】 請求項３において，ダミー抵抗Ｒｘをブリッジ回路の４つの抵抗Ｒ1 ，Ｒ2 ， Ｒ3 ，Ｒ4 より十分大きくしたので，本考案の診断回路を接続した状態でも，加 速度センサの出力に与える影響はきわめて小さい。したがって，常時診断するこ とが可能となる。In claim 3, since the dummy resistor Rx is made sufficiently larger than the four resistors R 1 , R 2 , R 3 , and R 4 of the bridge circuit, even when the diagnostic circuit of the present invention is connected, the output of the acceleration sensor is The impact on this is extremely small. Therefore, constant diagnosis is possible.
【００１２】0012
以下，本考案の一実施例を図１〜図６を参照して説明する。半導体加速度セン サ自体は図５に示した従来例と同様で，図１に示すように，ピエゾ抵抗素子を用 いた４つの抵抗Ｒ1 ，Ｒ2 ，Ｒ3 ，Ｒ4 でホイートストーンブリッジ回路１を構 成し，このブリッジ回路１の２つのブリッジ端子Ａ，Ｂを差動増幅器２に接続し て半導体加速度センサを構成している。実施例の半導体加速度センサは，図２， 図３に概略の外観を示すように，片持ちの台板１８にホイートストーンブリッジ 回路を構成するピエゾ抵抗素子による４つの抵抗Ｒ1 ，Ｒ2 ，Ｒ3 ，Ｒ4 を配置 し，台板１８の先端に感度を高めるための重り１９を取り付けた構造である。例 えば矢印ａ方向に加速度が加わった時，ピエゾ抵抗素子である抵抗Ｒ1 ，Ｒ2 ， Ｒ3 ，Ｒ4 の抵抗値が変化する。この半導体加速度センサにおける前記ブリッジ 回路１の２つのブリッジ端子Ａ，Ｂに本考案の診断回路２０を接続する。すなわ ち，この診断回路２０は，ブリッジ回路１の２つのブリッジ端子Ａ，Ｂにそれぞ れ接続される診断入力端子Ｐ，Ｑを持ち，各診断入力端子Ｐ，Ｑと前記各ブリッ ジ端子Ａ，Ｂとの間をそれぞれダミー抵抗Ｒｘを介在させて接地し，前記２つの 診断入力端子Ｐ，Ｑごとに，各入力端子Ｐ，Ｑから入力されるブリッジ端子電圧 ＶA ，ＶB と設定上限電圧ＶH および設定下限電圧ＶL とをそれぞれ比較する ２つの比較器２１からなるウインドコンパレータ２２，２３を設けている。なお ，比較器２１は，Ｌレベル（Ｌｏｗレベル）でオン，Ｈレベル（Ｈｉｇｈレベル ）でオフとなるオープンコレクタなので，ウインドコンパレータ２２，２３の出 力側に，Ｈレベル入力の際に出力電圧を得るための電圧Ｖｐをプリアップ抵抗２ ４を介して印加する。また，前記ブリッジ端子Ａ，Ｂと前記ダミ−抵抗Ｒx 分岐 部との間に，診断時以外の時に診断回路２０をブリッジ回路１から切り離すため のスイッチ２５（Ｓｗ１，Ｓｗ２）を設けている。詳細は省略するが，スイッチ ２５はＣＰＵに接続され，ＣＰＵにより制御される。An embodiment of the present invention will be described below with reference to FIGS. 1 to 6. The semiconductor acceleration sensor itself is similar to the conventional example shown in FIG . 5 , and as shown in FIG. The two bridge terminals A and B of this bridge circuit 1 are connected to a differential amplifier 2 to form a semiconductor acceleration sensor. As shown in the schematic appearance in FIGS. 2 and 3, the semiconductor acceleration sensor of the embodiment has four resistors R 1 , R 2 , It has a structure in which R 3 and R 4 are arranged, and a weight 19 is attached to the tip of the base plate 18 to increase sensitivity. For example, when acceleration is applied in the direction of arrow a, the resistance values of the piezoresistive elements R 1 , R 2 , R 3 , and R 4 change. A diagnostic circuit 20 of the present invention is connected to two bridge terminals A and B of the bridge circuit 1 in this semiconductor acceleration sensor. That is, this diagnostic circuit 20 has diagnostic input terminals P and Q connected to the two bridge terminals A and B of the bridge circuit 1, respectively, and the diagnostic input terminals P and Q are connected to each of the bridge terminals A and B, respectively. For each of the two diagnostic input terminals P and Q, the bridge terminal voltages VA and VB input from the respective input terminals P and Q, the set upper limit voltage VH and the set lower limit voltage are grounded through a dummy resistor Rx. Window comparators 22 and 23 each consisting of two comparators 21 are provided to respectively compare VL and VL. Note that the comparator 21 is an open collector that is turned on at L level (Low level) and turned off at H level (High level), so the output voltage is obtained on the output side of window comparators 22 and 23 when H level input is applied. A voltage Vp for this purpose is applied via the pre-up resistor 24. Further, switches 25 (Sw1, Sw2) are provided between the bridge terminals A, B and the dummy resistor Rx branch for disconnecting the diagnostic circuit 20 from the bridge circuit 1 at times other than during diagnosis. Although details are omitted, the switch 25 is connected to and controlled by the CPU.
【００１３】 上記構成の診断回路２０は，電源投入時にＣＰＵからの信号により２つのスイ ッチ２５をオンとして，ブリッジ回路１の４つの抵抗Ｒ1 ，Ｒ2 ，Ｒ3 ，Ｒ4 の 断線の有無の診断を行う。この場合，ウインドコンパレータ２２，２３に入力さ れるブリッジ端子電圧ＶA ，ＶB は，数式１，数２の通りである。The diagnostic circuit 20 configured as described above turns on the two switches 25 in response to a signal from the CPU when the power is turned on, and checks whether or not the four resistors R 1 , R 2 , R 3 , and R 4 of the bridge circuit 1 are disconnected. Make a diagnosis. In this case, the bridge terminal voltages VA and VB input to the window comparators 22 and 23 are as shown in Equations 1 and 2.
【数１】 [Math 1]
【数２】 そして，図４に示すように，ブリッジ端子電圧ＶA ，ＶB が設定上限電圧ＶH と設定下限電圧ＶL との間にある場合は，ウインドコンパレータ２２，２３の出 力がＨｉｇｈとなり，４つの抵抗Ｒ1 ，Ｒ2 ，Ｒ3 ，Ｒ4 のいずれも断線してい ないと診断する。また，ブリッジ端子電圧ＶA ，ＶB がＶH とＶL との間から 外れたとき，ウインドコンパレータ２２，２３の出力がＬｏｗとなり，断線して いることを検出する。４つの抵抗Ｒ1 ，Ｒ2 ，Ｒ3 ，Ｒ4 の断線状態と，ウイン ドコンパレータ２２，２３の出力すなわち診断回路２０の出力との関係は，表１ の検出方法の欄に示す通りである。Ｌｏｗ（１）はブリッジ端子電圧ＶB 側の診 断回路出力（ＯＵＴ１），Ｌｏｗ（２）はブリッジ端子電圧ＶA 側の診断回路出 力（ＯＵＴ２）を示す。[Math 2] As shown in FIG. 4, when the bridge terminal voltages VA and VB are between the set upper limit voltage VH and the set lower limit voltage VL, the outputs of the window comparators 22 and 23 become High, and the four resistors R 1 , It is diagnosed that none of R 2 , R 3 , and R 4 is disconnected. Further, when the bridge terminal voltages VA and VB deviate from the range between VH and VL, the outputs of the window comparators 22 and 23 become Low, and a disconnection is detected. The relationship between the disconnection states of the four resistors R 1 , R 2 , R 3 , and R 4 and the outputs of the window comparators 22 and 23, that is, the output of the diagnostic circuit 20, is as shown in the detection method column of Table 1. Low (1) indicates the diagnostic circuit output (OUT1) on the bridge terminal voltage VB side, and Low (2) indicates the diagnostic circuit output (OUT2) on the bridge terminal voltage VA side.
【表１】 [Table 1]
【００１４】 また，抵抗Ｒ1 ，Ｒ2 及び／又は抵抗Ｒ3 ，Ｒ4 が断線状態となった場合には ，Ａ点，Ｂ点を抵抗Ｒｘを介して接地し，Ａ点，Ｂ点の電位が不定となることを 防止する。[0014] Furthermore, if the resistors R 1 and R 2 and/or the resistors R 3 and R 4 are disconnected, the points A and B are grounded through the resistor Rx, and the points A and B are connected to the ground. Prevents potential from becoming unstable.
【００１５】 また，前記ダミー抵抗Ｒx をブリッジ回路１の４つの抵抗Ｒ1 ，Ｒ2 ，Ｒ3 ， Ｒ4 より十分大きくすると，ウインドコンパレータ２２，２３に入力されるブリ ッジ端子電圧ＶA ，ＶB は，数式３，数４の通り（数１，および数２において Ｒｘを無限大としたもの）となり，Ｒｘの影響を受けない。つまり，ブリッジ端 子電圧ＶA ，ＶB は，診断回路２０が接続されていることによる影響を受けず ，半導体加速度センサの出力が診断回路２０の影響を受けない。したがって，ス イッチ２５を常時オンとして，常時診断を行うことができる。Furthermore, if the dummy resistor Rx is made sufficiently larger than the four resistors R 1 , R 2 , R 3 , and R 4 of the bridge circuit 1, the bridge terminal voltages VA and VB input to the window comparators 22 and 23 are as follows. As shown in Equations 3 and 4 (where Rx is set to infinity in Equations 1 and 2), it is not affected by Rx. That is, the bridge terminal voltages VA and VB are not affected by the connection of the diagnostic circuit 20, and the output of the semiconductor acceleration sensor is not affected by the diagnostic circuit 20. Therefore, diagnosis can be performed at all times by keeping the switch 25 on all the time.
【数３】 [Math 3]
【数４】 [Math 4]
【００１６】 なお，上述した故障診断の説明においては，診断対象となる故障モードを，半 導体加速度センサのブリッジ回路を構成する４つの抵抗Ｒ1 ，Ｒ2 ，Ｒ3 ，Ｒ4 の断線に限って説明したが，電気的にこれらの抵抗の断線と同等である種々の故 障を検出することができることはいうまでもない。In the above description of the fault diagnosis, the fault mode to be diagnosed is limited to the disconnection of the four resistors R 1 , R 2 , R 3 , and R 4 that constitute the bridge circuit of the semiconductor acceleration sensor. As described above, it goes without saying that various faults electrically equivalent to disconnections in these resistors can be detected.
【００１７】[0017]
本考案によれば，入力端子側をダミー抵抗を介在させて接地したウインドコン パレータにより，ブリッジ回路の２つのブリッジ端子Ａ，Ｂの設定上限電圧ＶH および設定下限電圧ＶL を監視するものであるから，ブリッジ回路の４つの抵抗 のいずれが断線しても，必ずその断線を検出できる。 According to the present invention, a window controller whose input terminal side is grounded via a dummy resistor The setting upper limit voltage VH of the two bridge terminals A and B of the bridge circuit is set by the parator. and the set lower limit voltage VL, the four resistors of the bridge circuit are Even if any of the wires breaks, the wire breakage can always be detected.
【００１８】 請求項２によれば，ブリッジ端子ＶA ，ＶB とダミ−抵抗分岐部との間にス イッチを設けてたので，診断しない時にはこのスイッチをオフとすることで，診 断回路が加速度センサの出力に影響を与えることを完全に防止できる。[0018] According to claim 2, a strip is provided between the bridge terminals VA, VB and the dummy resistor branch. A switch was installed, so when not diagnosing, this switch could be turned off. It is possible to completely prevent a disconnection from affecting the output of the acceleration sensor.
【００１９】 請求項３によれば，ダミー抵抗Ｒｘをホイートストーンブリッジの４つの抵抗 Ｒ1 ，Ｒ2 ，Ｒ3 ，Ｒ4 より十分大きくしたので，本考案の診断回路を接続した 状態でも，加速度センサの出力に与える影響は小さく，したがって，常時診断す ることが可能となる。According to claim 3, since the dummy resistor Rx is made sufficiently larger than the four resistors R 1 , R 2 , R 3 , and R 4 of the Wheatstone bridge, even when the diagnostic circuit of the present invention is connected, The effect on the output of the acceleration sensor is small, so constant diagnosis is possible.
【図１】本考案の半導体加速度センサの診断回路の一実
施例を示す回路図である。FIG. 1 is a circuit diagram showing an embodiment of a diagnostic circuit for a semiconductor acceleration sensor according to the present invention.
【図２】一実施例の半導体加速度センサの外観を示す側
面図である。FIG. 2 is a side view showing the appearance of a semiconductor acceleration sensor according to an embodiment.
【図３】同半導体加速度センサの外観を示す平面図であ
る。FIG. 3 is a plan view showing the appearance of the semiconductor acceleration sensor.
【図４】ウインドコンパレータに入力されるブリッジ端
子電圧ＶA ，ＶB と設定上限電圧ＶH および設定下限
電圧ＶL とを示す図である。FIG. 4 is a diagram showing bridge terminal voltages VA and VB input to a window comparator, and a set upper limit voltage VH and a set lower limit voltage VL.
【図５】従来の半導体加速度センサを回路で示した図で
ある。FIG. 5 is a circuit diagram showing a conventional semiconductor acceleration sensor.
【図６】従来例として，機械式の加速度センサを備えた
電気回路における加速度センサの断線等を検出する診断
回路を説明するもので，機械式の加速度センサを用いた
エアバッグ装置の電気回路である。[Fig. 6] As a conventional example, this diagram describes a diagnostic circuit that detects disconnection of an acceleration sensor in an electrical circuit equipped with a mechanical acceleration sensor. be.
１ ホイートストーンブリッジ回路 ２ 差動増幅器（ＡＭＰ） ２０ 診断回路 ２１ 比較器 ２２，２３ ウインドコンパレータ ２５ スイッチ Ｒ1 ，Ｒ2 ，Ｒ3 ，Ｒ4 ピエゾ抵抗素子による抵抗 Ｐ，Ｑ 診断入力端子 Ｒｘ ダミー抵抗 ＶH 設定上限電圧 ＶL 設定下限電圧1 Wheatstone bridge circuit 2 Differential amplifier (AMP) 20 Diagnosis circuit 21 Comparator 22, 23 Window comparator 25 Switch R 1 , R 2 , R 3 , R 4 Resistance P, Q by piezo resistance element Diagnosis input terminal Rx Dummy Resistance VH Setting upper limit voltage VL Setting lower limit voltage
Claims (3)
1 ，Ｒ2 ，Ｒ3 ，Ｒ4でホイートストーンブリッジ回路
を構成し，このホイートストーンブリッジ回路の２つの
ブリッジ端子Ａ，Ｂを差動増幅器に接続してなる半導体
加速度センサの故障を診断する診断回路であって，前記
ホイートストーンブリッジ回路の２つのブリッジ端子
Ａ，Ｂにそれぞれ接続される診断入力端子Ｐ，Ｑを持
ち，各診断入力端子と前記各ブリッジ端子Ａ，Ｂとの間
をそれぞれダミー抵抗Ｒｘを介在させて接地し，前記２
つの診断入力端子ごとに，各入力端子から入力されるブ
リッジ端子電圧ＶA ，ＶBと設定上限電圧ＶH および
設定下限電圧ＶL とをそれぞれ比較する２つの比較器か
らなるウインドコンパレータを設けたことを特徴とする
半導体加速度センサの診断回路。[Claim 1] Four resistors R using piezoresistive elements
1 , R2 , R3 , and R4 constitute a Wheatstone bridge circuit, and the two bridge terminals A and B of this Wheatstone bridge circuit are connected to a differential amplifier. Diagnosing the failure of a semiconductor acceleration sensor. A diagnostic circuit having diagnostic input terminals P and Q respectively connected to two bridge terminals A and B of the Wheatstone bridge circuit, and between each diagnostic input terminal and each of the bridge terminals A and B. are grounded through dummy resistors Rx, respectively, and
The present invention is characterized in that a window comparator consisting of two comparators is provided for each of the two diagnostic input terminals to compare the bridge terminal voltages VA and VB inputted from each input terminal with the set upper limit voltage VH and the set lower limit voltage VL, respectively. A diagnostic circuit for semiconductor acceleration sensors.
部との間にスイッチを設けたことを特徴とする請求項１
記載の半導体加速度センサの診断回路。2. Claim 1, wherein a switch is provided between the bridge terminal and the dummy resistor branch.
A diagnostic circuit for the semiconductor acceleration sensor described above.
ブリッジ回路の４つの抵抗Ｒ1 ，Ｒ2 ，Ｒ3 ，Ｒ4 より
十分大きくして，常時診断を行うようにしたことを特徴
とする請求項１記載の半導体加速度センサの診断回路。3. The dummy resistor Rx is made sufficiently larger than the four resistors R 1 , R 2 , R 3 , and R 4 of the Wheatstone bridge circuit so that constant diagnosis is performed. 1. A diagnostic circuit for a semiconductor acceleration sensor according to 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1967591U JP2538185Y2 (en) | 1991-03-06 | 1991-03-06 | Diagnostic circuit for semiconductor acceleration sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1967591U JP2538185Y2 (en) | 1991-03-06 | 1991-03-06 | Diagnostic circuit for semiconductor acceleration sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04109371U true JPH04109371U (en) | 1992-09-22 |
| JP2538185Y2 JP2538185Y2 (en) | 1997-06-11 |
Family
ID=31905912
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1967591U Expired - Lifetime JP2538185Y2 (en) | 1991-03-06 | 1991-03-06 | Diagnostic circuit for semiconductor acceleration sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2538185Y2 (en) |
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|---|---|---|---|---|
| JPH06194379A (en) * | 1992-12-25 | 1994-07-15 | Mitsubishi Electric Corp | Semiconductor acceleration detector |
| JP2007139667A (en) * | 2005-11-21 | 2007-06-07 | Fujitsu Ltd | Sensor detecting device and sensor |
| JP2010236992A (en) * | 2009-03-31 | 2010-10-21 | Denso Corp | Sensor device |
| JP4711248B2 (en) * | 2000-09-20 | 2011-06-29 | センサータ テクノロジーズ インコーポレーテッド | Method and apparatus for detecting excessive negative offset of a sensor |
| WO2011162240A1 (en) * | 2010-06-25 | 2011-12-29 | 日立オートモティブシステムズ株式会社 | Circuit for detecting disconnection of bridge circuit and system having means for detecting disconnection |
| WO2013002361A1 (en) * | 2011-06-30 | 2013-01-03 | 三菱重工業株式会社 | Cell system |
| JP2015021790A (en) * | 2013-07-17 | 2015-02-02 | Tdk株式会社 | Method and device for detecting fault in bridge circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06194379A (en) * | 1992-12-25 | 1994-07-15 | Mitsubishi Electric Corp | Semiconductor acceleration detector |
| JP4711248B2 (en) * | 2000-09-20 | 2011-06-29 | センサータ テクノロジーズ インコーポレーテッド | Method and apparatus for detecting excessive negative offset of a sensor |
| JP2007139667A (en) * | 2005-11-21 | 2007-06-07 | Fujitsu Ltd | Sensor detecting device and sensor |
| EP1795903A2 (en) | 2005-11-21 | 2007-06-13 | Fujitsu Ltd. | Apparatus for detecting the failure of a sensor |
| US7271595B2 (en) | 2005-11-21 | 2007-09-18 | Fujitsu Limited | Sensor detection apparatus and sensor |
| JP2010236992A (en) * | 2009-03-31 | 2010-10-21 | Denso Corp | Sensor device |
| CN102959411A (en) * | 2010-06-25 | 2013-03-06 | 日立汽车系统株式会社 | Circuit for detecting disconnection of bridge circuit and system having means for detecting disconnection |
| EP2587270A4 (en) * | 2010-06-25 | 2018-04-18 | Hitachi Automotive Systems, Ltd. | Circuit for detecting disconnection of bridge circuit and system having means for detecting disconnection |
| JP2012008014A (en) * | 2010-06-25 | 2012-01-12 | Hitachi Automotive Systems Ltd | Disconnection detecting circuit for bridge circuit and system having disconnection detecting means |
| US9229040B2 (en) | 2010-06-25 | 2016-01-05 | Hitachi Automotive Systems, Ltd. | Disconnection detection circuit for bridge circuit and system including disconnection detecting means |
| WO2011162240A1 (en) * | 2010-06-25 | 2011-12-29 | 日立オートモティブシステムズ株式会社 | Circuit for detecting disconnection of bridge circuit and system having means for detecting disconnection |
| JP2013015330A (en) * | 2011-06-30 | 2013-01-24 | Mitsubishi Heavy Ind Ltd | Battery system |
| WO2013002361A1 (en) * | 2011-06-30 | 2013-01-03 | 三菱重工業株式会社 | Cell system |
| JP2015021790A (en) * | 2013-07-17 | 2015-02-02 | Tdk株式会社 | Method and device for detecting fault in bridge circuit |
| JP2020020792A (en) * | 2018-07-19 | 2020-02-06 | ティディケイ−ミクロナス ゲー・エム・ベー・ハー | Hall sensor and method for operating the same |
| WO2020084902A1 (en) * | 2018-10-26 | 2020-04-30 | 富士電機株式会社 | Pressure sensor |
| CN111989556A (en) * | 2018-10-26 | 2020-11-24 | 富士电机株式会社 | Pressure sensor |
| JPWO2020084902A1 (en) * | 2018-10-26 | 2021-03-25 | 富士電機株式会社 | Pressure sensor |
| CN111989556B (en) * | 2018-10-26 | 2022-05-10 | 富士电机株式会社 | Pressure sensor |
| US11415473B2 (en) | 2018-10-26 | 2022-08-16 | Fuji Electric Co., Ltd. | Pressure sensor having a failure detection unit |
| CN109781292A (en) * | 2019-01-31 | 2019-05-21 | 大禹电气科技股份有限公司 | Three-wire system platinum resistance thermometer sensor, break detection circuit and detection device and detection method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2538185Y2 (en) | 1997-06-11 |
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