JP2011215026A - Abnormality determination device of analog sensor circuit - Google Patents
Abnormality determination device of analog sensor circuit Download PDFInfo
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本発明は、アナログセンサ回路に係る異常の有無を判定する異常判定装置に関し、特に車両用アナログセンサ回路の異常判定装置に関する。 The present invention relates to an abnormality determination device that determines the presence or absence of an abnormality related to an analog sensor circuit, and more particularly to an abnormality determination device for an analog sensor circuit for a vehicle.
従来、車両の状態を検出するアナログセンサ回路に係る異常を判定するアナログセンサ異常判定装置として、特許文献１に記載のものが知られている。 2. Description of the Related Art Conventionally, an analog sensor abnormality determination device that determines abnormality relating to an analog sensor circuit that detects the state of a vehicle is disclosed in Patent Document 1.
特許文献１に記載の異常判定装置では、上記アナログセンサ回路に係る異常がある場合には車両の状態を正確に検出することができないため、当該センサ回路を２重系にすることで同センサ回路の異常を判定している。すなわち、２重系のセンサ回路うち一方のセンサ回路に異常があれば、正常な他方のセンサ回路と出力に差が生じるため、この出力差に基づいてセンサ回路に係る異常の有無を判定する。アナログセンサ回路に係る異常としては、当該センサの出力端子に導電性の異物が付着して同出力端子が当該異物を介してグランドに接続されてしまう異常（以下「不完全ショート異常」という）がある。 In the abnormality determination device described in Patent Document 1, when there is an abnormality related to the analog sensor circuit, it is impossible to accurately detect the state of the vehicle. An abnormality is judged. That is, if there is an abnormality in one of the dual sensor circuits, there is a difference in output from the other normal sensor circuit, so the presence or absence of an abnormality related to the sensor circuit is determined based on this output difference. As an abnormality relating to the analog sensor circuit, there is an abnormality (hereinafter referred to as “incomplete short-circuit abnormality”) in which conductive foreign matter adheres to the output terminal of the sensor and the output terminal is connected to the ground via the foreign matter. is there.
しかしながら、従来のセンサ回路を２重系にする構成では、２つのセンサを用いるため、製造コストが高くなるという問題がある。
本発明は、センサ回路を２重系にすることなく、不完全ショート異常があることを判定する異常判定装置を提供することを目的とする。
However, in the configuration in which the conventional sensor circuit is a double system, since two sensors are used, there is a problem that the manufacturing cost increases.
An object of this invention is to provide the abnormality determination apparatus which determines that there exists an incomplete short circuit abnormality, without making a sensor circuit into a double system.
請求項１に記載の発明は、直流電源に駆動されるアナログ出力の物理量センサであって、前記直流電源に接続される電源端子と、グランドに接続されるグランド端子と、物理量に相関する検出信号を出力する出力端子とを有し、前記出力端子及び前記グランド端子の間に設けられ前記物理量に応じて抵抗値が変化する可変抵抗器と前記電源端子及び前記出力端子の間に設けられた定抵抗器とからなる回路を等価回路とする物理量センサを備えて構成されるセンサ回路に適用される異常判定装置に係るものである。そして、請求項１に記載の発明では、前記グランド端子とグランドとの接続の断接を切り替える切替手段と、前記切替手段により前記グランド端子とグランドとの接続を遮断させた状態における前記物理量センサの検出信号の信号レベルを取得し、当該信号レベルが所定値よりも低い場合に、前記物理量センサの出力端子が導電性の異物を介してグランドに接続される不完全ショート異常があることを判定する異常判定手段と、を備えている。 The invention according to claim 1 is an analog output physical quantity sensor driven by a DC power supply, wherein a power supply terminal connected to the DC power supply, a ground terminal connected to the ground, and a detection signal correlated with the physical quantity A variable resistor provided between the output terminal and the ground terminal, the resistance value of which varies according to the physical quantity, and a constant resistor provided between the power supply terminal and the output terminal. The present invention relates to an abnormality determination device applied to a sensor circuit configured by including a physical quantity sensor having a circuit including a resistor as an equivalent circuit. And in invention of Claim 1, the switching means which switches connection / disconnection of the said ground terminal and a ground, The said physical quantity sensor in the state which interrupted | blocked the connection of the said ground terminal and a ground by the said switching means The signal level of the detection signal is acquired, and when the signal level is lower than a predetermined value, it is determined that there is an incomplete short circuit abnormality in which the output terminal of the physical quantity sensor is connected to the ground via a conductive foreign object An abnormality determination means.
上記センサ回路において、物理量センサのグランド端子とグランドとの接続を切断すると、不完全ショート異常がある場合の検出信号の信号レベルが、不完全ショート異常がない場合の検出信号の信号レベルよりも低くなる。
すなわち、物理量センサのグランド端子とグランドとの接続を切断すると、当該物理量センサの等価回路において可変抵抗のグランド側が切断され、当該物理量センサの検出信号の信号レベルは同物理量センサの検出対象である物理量に応じて変化しなくなる。また、不完全ショート異常がない場合には、物理量センサの出力端子はグランドに接続されていない。一方、不完全ショート異常がある場合には、物理量センサの出力端子は導電性の異物を介してグランドに接続される。そのため、物理量センサの出力端子から出力される検出信号の信号レベルは、不完全ショート異常の発生により低下する。
よって、請求項１に記載の発明のように、切替手段によりグランド端子とグランドとの接続を遮断させた状態における物理量センサの検出信号の信号レベルが所定値よりも低い場合に、不完全ショート異常があることを判定することができる。これにより、センサ回路を２重系にすることなく不完全ショート異常があることを判定することができる。
In the above sensor circuit, if the connection between the ground terminal of the physical quantity sensor and the ground is disconnected, the signal level of the detection signal when there is an incomplete short circuit abnormality is lower than the signal level of the detection signal when there is no incomplete short circuit abnormality. Become.
That is, when the connection between the ground terminal of the physical quantity sensor and the ground is disconnected, the ground side of the variable resistor is disconnected in the equivalent circuit of the physical quantity sensor, and the signal level of the detection signal of the physical quantity sensor is the physical quantity that is the detection target of the physical quantity sensor. It will not change according to. When there is no incomplete short circuit abnormality, the output terminal of the physical quantity sensor is not connected to the ground. On the other hand, when there is an incomplete short circuit abnormality, the output terminal of the physical quantity sensor is connected to the ground via a conductive foreign matter. For this reason, the signal level of the detection signal output from the output terminal of the physical quantity sensor decreases due to the occurrence of an incomplete short circuit abnormality.
Therefore, as in the first aspect of the invention, when the signal level of the detection signal of the physical quantity sensor is lower than the predetermined value in the state where the connection between the ground terminal and the ground is interrupted by the switching means, the incomplete short circuit abnormality Can be determined. Thereby, it can be determined that there is an incomplete short circuit abnormality without making the sensor circuit a double system.
請求項２に記載の発明では、前記センサ回路は、前記物理量センサの検出信号を前記直流電源の電源電圧でプルアップするプルアップ抵抗器を備え、前記異常判定手段は、前記検出信号の信号レベルが前記直流電源の電源電圧レベルである場合に前記不完全ショート異常がないことを判定する。 According to a second aspect of the present invention, the sensor circuit includes a pull-up resistor that pulls up a detection signal of the physical quantity sensor with a power supply voltage of the DC power supply, and the abnormality determination unit is configured to detect a signal level of the detection signal. Is determined to be free of the incomplete short circuit abnormality when the power supply voltage level of the DC power supply is present.
上記センサ回路において、物理量センサのグランド端子とグランドとの接続を切断すると、不完全ショート異常がない場合の検出信号の信号レベルは直流電源の電源電圧レベルとなる。
よって、請求項２に記載の発明のように、グランド端子とグランドとの接続を切断させた状態における物理量センサの検出信号の信号レベルが、直流電源の電源電圧レベルである場合に、不完全ショート異常がないことを判定することができる。
In the sensor circuit, when the connection between the ground terminal of the physical quantity sensor and the ground is cut, the signal level of the detection signal when there is no incomplete short circuit abnormality is the power supply voltage level of the DC power supply.
Therefore, when the signal level of the detection signal of the physical quantity sensor in the state where the connection between the ground terminal and the ground is disconnected as in the invention described in claim 2, the incomplete short circuit occurs. It can be determined that there is no abnormality.
請求項３に記載の発明では、前記物理量センサ以外のデバイスが当該物理量センサと共通のグランドに接続されており、前記物理量センサのグランド端子とグランドとの間のみを接続するグランド経路を設け、前記切替手段は前記グランド経路を断接する。 In the invention according to claim 3, a device other than the physical quantity sensor is connected to a common ground with the physical quantity sensor, and a ground path that connects only between the ground terminal of the physical quantity sensor and the ground is provided, The switching means connects and disconnects the ground path.
請求項３に記載の発明によれば、不完全ショート異常の有無の判定に際し、物理量センサのグランド端子とグランドとの間のみを接続するグランド経路を切断するため、当該グランド経路の切断によって物理量センサ以外のデバイスとグランドとの間の接続が切断されることはない。 According to the third aspect of the present invention, in determining whether or not there is an incomplete short circuit abnormality, the ground path that connects only between the ground terminal of the physical quantity sensor and the ground is disconnected. The connection between the non-device and the ground is not broken.
（実施形態）
本実施例ではアナログセンサ回路の故障判定装置として、車両のエンジン負圧を検出する負圧センサ１の故障を判定するＥＣＵ２について説明する（図１参照）。
(Embodiment)
In this embodiment, an ECU 2 that determines a failure of the negative pressure sensor 1 that detects an engine negative pressure of a vehicle will be described as a failure determination device for an analog sensor circuit (see FIG. 1).
物理量センサとしての負圧センサ１は、エンジン負圧に相関する検出信号を出力する信号出力端子ＴＳ１、電源接続端子ＴＳ２、及びグランド接続端子ＴＳ３を備えている。この負圧センサ１は、信号出力端子ＴＳ１とグランド接続端子ＴＳ３との間に設けられてエンジン負圧に応じて抵抗値が変化する可変抵抗器１１と、電源接続端子ＴＳ２と信号出力端子ＴＳ１との間に設けられた定抵抗器１２とから構成される等価回路、すなわち可変抵抗器１１と定抵抗器１２とによる分圧回路として表現され得る。
負圧センサ１はＥＣＵ２に接続されている。詳しくは、信号出力端子ＴＳ１はＥＣＵ２のアナログ入力端子ＴＥ１に、電源接続端子ＴＳ２はＥＣＵ２の電源端子ＴＥ２に、グランド接続端子ＴＳ３はＥＣＵ２のグランド端子ＴＥ３に接続されている。
The negative pressure sensor 1 as a physical quantity sensor includes a signal output terminal TS1, a power supply connection terminal TS2, and a ground connection terminal TS3 that output a detection signal correlated with engine negative pressure. This negative pressure sensor 1 is provided between a signal output terminal TS1 and a ground connection terminal TS3, and has a variable resistor 11 whose resistance value changes according to engine negative pressure, a power supply connection terminal TS2, and a signal output terminal TS1. It can be expressed as an equivalent circuit composed of a constant resistor 12 provided between them, that is, a voltage dividing circuit composed of a variable resistor 11 and a constant resistor 12.
The negative pressure sensor 1 is connected to the ECU 2. Specifically, the signal output terminal TS1 is connected to the analog input terminal TE1 of the ECU 2, the power connection terminal TS2 is connected to the power supply terminal TE2 of the ECU 2, and the ground connection terminal TS3 is connected to the ground terminal TE3 of the ECU 2.
ＥＣＵ２は、マイクロコンピュータ２１を備えて構成される周知の電子制御装置であり、負圧センサ１の検出信号に基づいて車両に係る各種制御を実行する。ＥＣＵ２において、電源端子ＴＥ２は、図示しない直流電源に接続されている。アナログ入力端子ＴＥ１は、定抵抗器２２を介してマイクロコンピュータ２１に接続されるとともに、定抵抗器２３により直流電源の電源電圧Ｖｃｃでプルアップされている。グランド端子ＴＥ３は、グランドラインＧＬを介してグランドに接続されている。グランドラインＧＬには、グランド端子ＴＥ３とグランドとの間の接続の断絶を切り替えるＦＥＴ（Field Effect Transistor）２４が設けられており、負圧センサ１以外のデバイスは接続されていない。グランドラインＧＬが「グランド経路」に相当し、ＦＥＴ２４が「切替手段」に相当する。 The ECU 2 is a well-known electronic control device that includes a microcomputer 21, and executes various controls related to the vehicle based on the detection signal of the negative pressure sensor 1. In the ECU 2, the power supply terminal TE2 is connected to a DC power supply (not shown). The analog input terminal TE1 is connected to the microcomputer 21 through the constant resistor 22, and is pulled up by the constant resistor 23 at the power supply voltage Vcc of the DC power supply. The ground terminal TE3 is connected to the ground via the ground line GL. The ground line GL is provided with an FET (Field Effect Transistor) 24 that switches disconnection between the ground terminal TE3 and the ground, and no devices other than the negative pressure sensor 1 are connected. The ground line GL corresponds to a “ground path”, and the FET 24 corresponds to a “switching unit”.
図２は、ＥＣＵ２に入力される負圧センサ１の検出信号の信号レベルＶｍ（以下「入力信号レベルＶｍ」という）とエンジン負圧との関係を示す特性図である。図２では、ＦＥＴ２４がオン状態、すなわち負圧センサ１のグランド接続端子ＴＳ３とグランドとが接続された状態を想定している。
入力信号レベルＶｍは、図２の実線で示すように、負圧センサ１の検出範囲（Ｐ１〜Ｐ２）内においてエンジン負圧が大きくなるほど高くなり、負圧センサ１の検出下限圧Ｐ１よりも小さい範囲において当該検出下限圧に対応する０Ｖ付近の電圧Ｖｌで一定となり、負圧センサ１の検出上限圧Ｐ２よりも大きい範囲において当該検出上限圧に対応する電源電圧Ｖｃｃ付近の電圧Ｖｈ１ｎで一定となる（次式１参照）。
FIG. 2 is a characteristic diagram showing the relationship between the signal level Vm (hereinafter referred to as “input signal level Vm”) of the detection signal of the negative pressure sensor 1 input to the ECU 2 and the engine negative pressure. In FIG. 2, it is assumed that the FET 24 is in an on state, that is, a state where the ground connection terminal TS3 of the negative pressure sensor 1 and the ground are connected.
As shown by the solid line in FIG. 2, the input signal level Vm increases as the engine negative pressure increases within the detection range (P1 to P2) of the negative pressure sensor 1, and is smaller than the detection lower limit pressure P1 of the negative pressure sensor 1. In the range, it becomes constant at a voltage Vl near 0 V corresponding to the detection lower limit pressure, and in a range larger than the detection upper limit pressure P2 of the negative pressure sensor 1, it becomes constant at a voltage Vh1n near the power supply voltage Vcc corresponding to the detection upper limit pressure. (See Formula 1 below).
Ｖｍ＝Ｖｃｃ×Ｒ３／（Ｒ１＋Ｒ３） ・・・式１
Ｒ１：定抵抗器２３の抵抗値
Ｒ３：可変抵抗器１１の抵抗値
Vm = Vcc × R3 / (R1 + R3) Formula 1
R1: Resistance value of the constant resistor 23 R3: Resistance value of the variable resistor 11
しかしながら、負圧センサ１の信号出力端子ＴＳ１が導電性の異物（例えば、はんだ屑や鉄屑）を介してグランドに接続される不完全ショート異常が発生すると、電源電圧Ｖｃｃが定抵抗器１２と可変抵抗器１１及び上記異物による抵抗の合成抵抗とにより分圧されて信号出力端子ＴＳ１に出力される。そのため、マイクロコンピュータ３への検出信号の入力信号レベルＶｍは、図２の一点鎖線で示すように、検出上限圧Ｐ２よりも小さいエンジン負圧Ｐ３で飽和して、検出上限圧Ｐ２に対応する電圧Ｖｈ１ｎよりも低い電圧Ｖｈ１ａで一定となる。 However, when an incomplete short circuit abnormality occurs in which the signal output terminal TS1 of the negative pressure sensor 1 is connected to the ground via conductive foreign matter (for example, solder scraps or iron scraps), the power supply voltage Vcc is connected to the constant resistor 12. The voltage is divided by the variable resistor 11 and the combined resistance of the above-described foreign matter and output to the signal output terminal TS1. Therefore, the input signal level Vm of the detection signal to the microcomputer 3 is saturated with the engine negative pressure P3 smaller than the detection upper limit pressure P2, as shown by the one-dot chain line in FIG. 2, and the voltage corresponding to the detection upper limit pressure P2 It becomes constant at a voltage Vh1a lower than Vh1n.
そこで、本発明では、ＦＥＴ２４をオフ状態、すなわち負圧センサ１のグランド接続端子ＴＳ３とグランドとの接続が切断された状態における入力信号レベルＶｍに基づいて、不完全ショート異常の有無を判定するようにしている。 Therefore, in the present invention, the presence / absence of an incomplete short circuit abnormality is determined based on the input signal level Vm when the FET 24 is in an off state, that is, when the ground connection terminal TS3 of the negative pressure sensor 1 is disconnected from the ground. I have to.
図３は、負圧センサ１の信号出力端子ＴＳ１が導電性の異物ＡＳを介してグランドに接続される不完全ショート異常が発生し、ＦＥＴ２４をオフ状態とした場合の負圧センサ１及びＥＣＵ２の回路図である。図４は、ＦＥＴ２４のオフ状態における入力信号レベルＶｍとエンジン負圧との関係を示す特性図である。図４において、実線は不完全ショート異常がない状態の上記関係を示し、一点鎖線は不完全ショート異常がある状態の上記関係を示している。
ＦＥＴ２４をオフ状態とすると、可変抵抗器１３を含む回路がオープン状態となるため、入力信号レベルＶｍは、図４に示すようにエンジン負圧によらず一定となる。ただし、入力信号レベルＶｍは、不完全ショート異常の有無により異なる電圧を示す。詳しくは、不完全ショート異常のない状態の入力信号レベルＶｍは、電源電圧Ｖｃｃ付近の電圧Ｖｈ２ｎ（Ｖｈ２ｎ＞Ｖｈ１ｎ）となり、不完全ショート異常のある状態の入力信号レベルＶｍは、上記電圧Ｖｈ２ｎよりも低い電圧Ｖｈ２ａとなる。
FIG. 3 shows the negative pressure sensor 1 and the ECU 2 when the FET 24 is turned off when an incomplete short circuit abnormality occurs in which the signal output terminal TS1 of the negative pressure sensor 1 is connected to the ground via the conductive foreign substance AS. It is a circuit diagram. FIG. 4 is a characteristic diagram showing the relationship between the input signal level Vm and the engine negative pressure when the FET 24 is in the OFF state. In FIG. 4, the solid line indicates the above relationship in a state where there is no incomplete short circuit abnormality, and the alternate long and short dash line indicates the above relationship in a state where there is an incomplete short circuit abnormality.
When the FET 24 is turned off, the circuit including the variable resistor 13 is opened, so that the input signal level Vm is constant regardless of the engine negative pressure as shown in FIG. However, the input signal level Vm shows a different voltage depending on the presence or absence of an incomplete short circuit abnormality. Specifically, the input signal level Vm in a state without incomplete short circuit abnormality is a voltage Vh2n (Vh2n> Vh1n) near the power supply voltage Vcc, and the input signal level Vm in a state with incomplete short circuit abnormality is higher than the voltage Vh2n. The voltage Vh2a becomes low.
不完全ショート異常がない状態の入力信号レベルＶｍを次式２に、不完全ショート異常がある状態の入力信号レベルＶｍを次式３に示す。
Ｖｍ≒Ｖｃｃ ・・・式２
Ｖｍ＝Ｖｃｃ×（Ｒ１＋Ｒ２）／（Ｒ１＋Ｒ２＋（Ｒ１×Ｒ２）／Ｒ４｝ ・・・式３
Ｒ４：異物ＡＳの抵抗値
The input signal level Vm in a state where there is no incomplete short circuit abnormality is shown in the following equation 2, and the input signal level Vm in a state where there is an incomplete short circuit abnormality is shown in the following equation 3.
Vm ≒ Vcc ... Formula 2
Vm = Vcc × (R1 + R2) / (R1 + R2 + (R1 × R2) / R4} Equation 3
R4: Resistance value of the foreign matter AS
不完全ショート異常がある状態では、バッテリ電圧が定抵抗器１２及び定抵抗器２３の合成抵抗と異物ＡＳによる抵抗とにより分圧されて信号出力端子ＴＳ１に出力される。そのため、不完全ショート異常がある状態の入力信号レベルＶｍは、不完全ショート異常がない状態の入力信号レベルＶｍよりも小さくなる。 In a state where there is an incomplete short circuit abnormality, the battery voltage is divided by the combined resistance of the constant resistor 12 and the constant resistor 23 and the resistance due to the foreign object AS and output to the signal output terminal TS1. Therefore, the input signal level Vm in a state where there is an incomplete short circuit abnormality is smaller than the input signal level Vm in a state where there is no incomplete short circuit abnormality.
この点に着目し、ＥＣＵ２は、不完全ショート異常の有無の判定処理において、はじめに、ＦＥＴ２４をオフ状態として、負圧センサ１のグランド接続端子ＴＳ３とグランドとの接続を遮断する。次に、ＥＣＵ２は、ＦＥＴ２４のオフ状態における入力信号レベルＶｍを取得する。詳しくは、ＥＣＵ２は、入力信号レベルＶｍをディジタル変換して電圧値として取得する。次に、ＥＣＵ２は、取得した入力信号レベルＶｍが所定のしきい電圧Ｖｔｈ（Ｖｈ２ａ＜Ｖｔｈ＜Ｖｈ２ｎ）よりも低いか否かを判定する。そして、ＥＣＵ２は、入力信号レベルＶｍがしきい電圧Ｖｔｈよりも低い場合に、不完全ショート異常があることを判定し、入力信号レベルＶｍがしきい電圧Ｖｔｈ以上である場合に、不完全ショート異常がないことを判定する。 Focusing on this point, the ECU 2 first turns off the FET 24 and cuts off the connection between the ground connection terminal TS3 of the negative pressure sensor 1 and the ground in the determination process for the presence or absence of the incomplete short circuit abnormality. Next, the ECU 2 acquires the input signal level Vm when the FET 24 is in the off state. Specifically, the ECU 2 digitally converts the input signal level Vm to obtain a voltage value. Next, the ECU 2 determines whether or not the acquired input signal level Vm is lower than a predetermined threshold voltage Vth (Vh2a <Vth <Vh2n). The ECU 2 determines that there is an incomplete short circuit abnormality when the input signal level Vm is lower than the threshold voltage Vth. If the input signal level Vm is equal to or higher than the threshold voltage Vth, the ECU 2 Judge that there is no.
以上説明したように、ＦＥＴ２４のオフ状態における入力信号レベルＶｍがしきい電圧Ｖｔｈに基づいて不完全ショート異常の有無を判定しているので、センサ回路を２重系にしなくても不完全ショート異常の有無を検出することができる。 As described above, since the input signal level Vm in the OFF state of the FET 24 determines the presence or absence of the incomplete short circuit abnormality based on the threshold voltage Vth, the incomplete short circuit abnormality can be achieved even if the sensor circuit is not doubled. The presence or absence of can be detected.
負圧センサ１の信号出力端子ＴＳ１を定抵抗器２２により電源電圧Ｖｃｃでプルアップしているため、ＦＥＴ２４のオフ状態、すなわち負圧センサ１の信号出力端子ＴＳ１とグランドとの接続が切断されている状態で不完全ショート異常がない場合の入力信号レベルＶｍは電源電圧Ｖｃｃ付近の電圧Ｖｈ２ｎとなる。そのため、入力信号レベルＶｍが電源電圧Ｖｃｃ付近の電圧レベルである場合に、不完全ショート異常でないことを判定することができる。 Since the signal output terminal TS1 of the negative pressure sensor 1 is pulled up with the power supply voltage Vcc by the constant resistor 22, the FET 24 is turned off, that is, the connection between the signal output terminal TS1 of the negative pressure sensor 1 and the ground is disconnected. When there is no incomplete short circuit abnormality, the input signal level Vm becomes the voltage Vh2n near the power supply voltage Vcc. Therefore, when the input signal level Vm is a voltage level near the power supply voltage Vcc, it can be determined that there is no incomplete short circuit abnormality.
負圧センサ１のグランド接続端子ＴＳ３をグランドラインＧＬを介してグランドと接続し、グランドラインＧＬに他のデバイスを接続しないようにしたので、不完全ショート異常の判定処理に際し、ＦＥＴ２４をオフ状態としても、他のデバイスとグランドとの接続が切断されることはない。 Since the ground connection terminal TS3 of the negative pressure sensor 1 is connected to the ground via the ground line GL and no other device is connected to the ground line GL, the FET 24 is turned off in the determination process of the incomplete short circuit abnormality. However, the connection between the other device and the ground is not cut off.
（他の実施形態）
上記実施形態では、圧力の増大に伴って検出信号の信号レベルが高くなる負圧センサ１によるセンサ回路を異常判定の対象としたが、本発明は、圧力の増大に伴って検出信号の信号レベルが低くなる負圧センサ１によるセンサ回路にも適用可能である。
また、上記実施形態では、負圧センサ１によるセンサ回路に係る不完全ショート異常の有無を判定するようにしたが、本発明の判定対象であるセンサ回路は負圧センサによるセンサ回路に限られず、本発明は他のアナログセンサによるセンサ回路にも適用可能である。
(Other embodiments)
In the above embodiment, the sensor circuit by the negative pressure sensor 1 whose detection signal signal level increases as the pressure increases is the target of abnormality determination. However, the present invention provides a signal level of the detection signal as the pressure increases. The present invention can also be applied to a sensor circuit using the negative pressure sensor 1 in which the pressure becomes low.
Moreover, in the said embodiment, although the presence or absence of the incomplete short circuit abnormality which concerns on the sensor circuit by the negative pressure sensor 1 was determined, the sensor circuit which is the determination object of this invention is not restricted to the sensor circuit by a negative pressure sensor, The present invention is also applicable to sensor circuits using other analog sensors.
上記実施形態では、負圧センサ１の信号出力端子ＴＳ１を電源電圧Ｖｃｃでプルアップしたが、電源電圧Ｖｃｃとは異なる電圧でプルアップしてもよい。
また、上記実施形態では、負圧センサ１の信号出力端子ＴＳ１をプルアップしたが、判定対象のアナログセンサによっては必ずしもプルアップする必要はない。
In the above embodiment, the signal output terminal TS1 of the negative pressure sensor 1 is pulled up with the power supply voltage Vcc, but may be pulled up with a voltage different from the power supply voltage Vcc.
Moreover, in the said embodiment, although the signal output terminal TS1 of the negative pressure sensor 1 was pulled up, it does not necessarily need to pull up depending on the analog sensor of judgment object.
１…負圧センサ（物理量センサ）、２…ＥＣＵ（異常判定手段）、１１…可変抵抗器、１２…定抵抗器、２１…マイクロコンピュータ、２２…定抵抗器、２３…定抵抗器、２４…ＦＥＴ（切替手段）、ＡＳ…異物、ＧＬ…グランドライン、ＴＥ１…アナログ入力端子、ＴＥ２…電源端子、ＴＥ３…グランド端子、ＴＳ１…信号出力端子、ＴＳ２…電源接続端子、ＴＳ３…グランド接続端子
DESCRIPTION OF SYMBOLS 1 ... Negative pressure sensor (physical quantity sensor), 2 ... ECU (abnormality determination means), 11 ... Variable resistor, 12 ... Constant resistor, 21 ... Microcomputer, 22 ... Constant resistor, 23 ... Constant resistor, 24 ... FET (switching means), AS ... foreign matter, GL ... ground line, TE1 ... analog input terminal, TE2 ... power supply terminal, TE3 ... ground terminal, TS1 ... signal output terminal, TS2 ... power supply connection terminal, TS3 ... ground connection terminal
Claims (3)
前記グランド接続端子とグランドとの接続の断接を切り替える切替手段と、
前記切替手段により前記グランド接続端子とグランドとの接続を切断させた状態における前記物理量センサの検出信号の信号レベルを取得し、当該信号レベルが所定のしきい電圧よりも低い場合に前記不完全ショート異常があることを判定する異常判定手段と、
を備えていることを特徴とする異常判定装置。 An analog output physical quantity sensor driven by a DC power supply, the power supply connection terminal connected to the DC power supply, the ground connection terminal connected to the ground, and the signal output terminal for outputting a detection signal correlated with the physical quantity; A variable resistor which is provided between the signal output terminal and the ground connection terminal and whose resistance value changes according to the physical quantity, and a constant resistor provided between the power supply connection terminal and the signal output terminal. Applicable to a sensor circuit comprising a physical quantity sensor having an equivalent circuit as a circuit consisting of: a signal output terminal of the physical quantity sensor connected to the ground through a conductive foreign object to determine whether there is an incomplete short circuit abnormality. In the abnormality determination device for determining,
Switching means for switching connection / disconnection between the ground connection terminal and the ground;
The signal level of the detection signal of the physical quantity sensor in a state in which the connection between the ground connection terminal and the ground is disconnected by the switching means, and the incomplete short circuit when the signal level is lower than a predetermined threshold voltage An abnormality determination means for determining that there is an abnormality;
An abnormality determination device comprising:
前記異常判定手段は、前記取得した検出信号の信号レベルが前記直流電源の電源電圧レベルである場合に前記不完全ショート異常がないことを判定することを特徴とする請求項1に記載の異常判定装置。 The sensor circuit includes a pull-up resistor that pulls up a detection signal of the physical quantity sensor with a power supply voltage of the DC power supply,
2. The abnormality determination according to claim 1, wherein the abnormality determination unit determines that the incomplete short circuit abnormality does not occur when a signal level of the acquired detection signal is a power supply voltage level of the DC power supply. apparatus.
前記物理量センサのグランド接続端子と前記グランドとの間のみを接続するグランド経路を設け、
前記切替手段は前記グランド経路を断接することを特徴とする請求項１又は２に記載の異常判定装置。
A device other than the physical quantity sensor is connected to the common ground with the physical quantity sensor,
Provide a ground path that connects only between the ground connection terminal of the physical quantity sensor and the ground,
The abnormality determination device according to claim 1, wherein the switching unit connects and disconnects the ground path.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014199182A (en) * | 2013-03-29 | 2014-10-23 | Tdk株式会社 | Magnetic sensor system |
| JP2015036634A (en) * | 2013-08-12 | 2015-02-23 | Ｎｅｃプラットフォームズ株式会社 | Power supply monitoring device, power supply device, information processing system and power supply monitoring method |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014199182A (en) * | 2013-03-29 | 2014-10-23 | Tdk株式会社 | Magnetic sensor system |
| US9297635B2 (en) | 2013-03-29 | 2016-03-29 | Tdk Corporation | Magnetic sensor system including two detection circuits |
| JP2015036634A (en) * | 2013-08-12 | 2015-02-23 | Ｎｅｃプラットフォームズ株式会社 | Power supply monitoring device, power supply device, information processing system and power supply monitoring method |
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