JP2008286706A - Sensor circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor circuit capable of detecting open trouble of a signal line in an inside of a device, without enlarging a device size. <P>SOLUTION: A mold IC 19 detects a pedaling operation for a brake pedal by a magnetic sensor IC 16 built in itself, and a control IC 17 is operated based on a detection signal from the magnetic sensor IC 16, to output an L signal from one terminal and an H signal from the other terminal when the brake pedal is not operated, and to output the H signal from the one terminal and the L signal from the other terminal when the brake pedal is operated. The control IC 17 self-diagnoses the presence of the open trouble in the signal output line 33c for connecting the magnetic sensor IC 16 to the control IC 17, by comparing the detection signal obtained from the magnetic sensor IC 16 with a partial potential output taken out from in the midway of one magnetic resistance R3 of a bridge circuit 16a. A self-diagnostic function is operated to output the L signals both the one terminal and the other terminal, when detecting the open trouble in the signal output line 33c, to inform an outside of the purport thereof. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sensor circuit that operates an apparatus in a state corresponding to the operation of the operation unit by detecting an operation of the operation unit and outputting an output signal corresponding to the operation to the apparatus.

  Conventionally, as shown in FIG. 11, an operation that an operator performs using the operation unit 81 is detected, and an H level signal is output from one of the two output terminals 82 and 83 while an L level signal is output from the other. There is an operation determination device 84 that switches the H / L level of the signal according to whether or not the operation unit 81 is operated. This type of operation determination device 84 is based on a detection IC 85 that detects whether or not the operation unit 81 is operated, and a signal output (voltage output) obtained from the detection IC 85, and outputs an H level signal (voltage) from one of the output terminals 82 and 83. Output) and a control IC 86 for outputting an L level signal (voltage output) from the other, and the first device 87 and the second device 88 connected to the output terminals 82 and 83, respectively, have an H level as an operation command. These devices 87 and 88 are operated by outputting signals and L level signals.

  As a specific operation of the operation determination device 84, when the detection IC 85 detects that the operation unit 81 is not operated, an L level signal is output from one output terminal 82 and an H level is output from the other output terminal 83. While outputting the signal, the first device 87 to which the L level signal is applied is stopped, and the second device 88 to which the H level signal is applied is activated. Further, when the operation determination device 84 detects that the operation unit 81 has been operated by the detection IC 85, the operation determination device 84 outputs an H level signal from one output terminal 82 and outputs an L level signal from the other output terminal 83. While the first device 87 to which the level signal is applied is activated, the second device 88 to which the L level signal is applied is deactivated.

  The detection IC 85 and the control IC 86 have their own connection terminals (for example, connection pins) attached to the substrate to which the detection IC 85 and the control IC 86 are attached using various bonding methods. By the way, the detection IC 85 and the control IC 86 are peeled off from the joint portion on the substrate due to the use of the operation determination device 84 in a vibration generation environment or a secular change, and the wiring connecting the IC and the substrate is in an open state. There are concerns about falling down. In this case, the detection IC 85 and the control IC 86 are not electrically connected via the signal line, the detection signal of the detection IC 85 is not output to the control IC 86, and the operation of the operation unit 81 is determined by the operation determination device. In 84, a problem that cannot be detected normally occurs.

Therefore, as a countermeasure, two detection elements 89 that detect the operation are provided in the detection IC 85 that detects the operation amount (operation presence / absence) of the operation unit 81, and the detection output of one of the detection elements 89a is detected. A countermeasure using a so-called dual technology is conceivable in which both detection signals of the two detection elements 89a and 89b are sent to the control IC 86 and the wiring open state is monitored by the control IC 86. The control IC 86 monitors whether or not the detection signals obtained from the detection elements 89a and 89b have different values, thereby monitoring the open state of the signal line, that is, the presence or absence of a wiring system failure between the detection IC 85 and the control IC 86. For example, Patent Documents 1 and 2 disclose double-system technology using a magnetic detection element (such as a magnetoresistive element or a Hall element) as the detection IC 85.
JP-A-9-292202 Japanese Patent Laid-Open No. 8-49575

  However, when the detection IC 85 uses a dual technology, an open failure of the signal line connecting the detection IC 85 and the control IC 86, that is, a failure of the operation determination device 84 can be seen, but the detection IC 85 has two detections. Since it is necessary to provide the elements 89a and 89b, there is a problem that the component size of the detection IC 85 and the operation determination device 84 is increased. Further, when the two detection elements 89a and 89b are provided in the detection IC 85, in this case, the detection element 89 requires a cost for two parts, and thus there is a problem that the part cost of the detection IC 85 and the operation determination device 84 is increased. .

  An object of the present invention is to provide a sensor circuit that can detect an open failure of a signal line inside a device without increasing the size of the device.

  In order to solve the above problems, in the present invention, a detection signal obtained from the detection circuit is detected by a control circuit that detects the operation of the operation unit by an operator with a detection circuit and is connected to the detection circuit via a wiring. In a sensor circuit that outputs a signal as an output signal in response to an operation of the operation unit to operate the device, an extraction unit that extracts a part of the output as a comparison output from one detection element that is a detection portion of the detection circuit; In the process of converting the detection signal of the detection circuit and outputting it as the output signal, the detection signal of the detection circuit is compared with the output for comparison obtained from the extraction means, thereby The output signal is a signal that can be used to determine whether or not an open failure is detected whether the output wiring is attached to the attachment destination, and that the output wiring is in an open state. And gist that a hydraulic circuit having a self-diagnostic function to output.

  According to this configuration, for example, when an operation unit composed of a knob or the like is operated, this operation is detected by the detection circuit, and a detection signal corresponding to the operation state is detected from the detection circuit. Circuit). The operation circuit outputs the detection signal obtained from the detection circuit as an output signal corresponding to the operation of the operation unit to operate the device. When the operation circuit obtains the detection signal from the detection circuit and supplies the output signal to the device, the operation circuit checks whether or not the output wiring connecting the detection circuit and the control circuit (that is, the operation circuit) is normally attached to the attachment destination. As a self-diagnosis, a comparison output, which is a part of the output of the detection circuit, is simultaneously fetched from the extraction means, and these values are compared to determine whether there is an open failure in the output wiring.

  By the way, when comparing the value of the detection signal with the value of the comparison output, since the comparison output is a part of the output of the detection circuit, the possible value relationship is that the detection signal exceeds the comparison output. Therefore, if the output wiring connecting the detection circuit and the control circuit is normally attached to the attachment destination, the detection signal enters the operation circuit in a state exceeding the comparison output. Therefore, when the detection signal is input from the detection circuit and the detection signal exceeds the output for comparison, the operation circuit determines that the output wiring connecting the detection circuit and the control circuit is normally attached to the attachment destination. The detection signal is output to the device as an output signal corresponding to the operation unit, and the devices are operated in an operating state corresponding to the operation at that time.

  On the other hand, when the detection circuit receives a detection signal from the detection circuit, if this detection signal falls below the comparison output, the output wiring connecting the detection circuit and the control circuit is not properly attached to the mounting destination, and the output It is determined that the work wiring is open. The operation circuit that has determined that the output wiring is in an open state outputs a signal that can notify that the output wiring is abnormal, that is, an abnormality notification to an apparatus or the like as an output signal. A device that has received this type of abnormality notification recognizes that the output wiring is open and the sensor circuit has failed, and takes measures such as discarding the output signal output by the sensor circuit at that time.

  Therefore, in this configuration, only one set of detection elements is provided in the detection circuit, and the detection signal obtained as the output of the detection circuit from this detection element is compared with the output for comparison extracted as a part of the output of the detection element. Thus, the presence or absence of an open failure in the output wiring is determined. For this reason, when determining the presence or absence of an open failure in the output wiring, only one set of detection elements is required for the detection circuit, so that the circuit size of the detection circuit at this time can be reduced. Therefore, when determining the presence or absence of an open failure in the output wiring, it is difficult to increase the size of the detection circuit and thus the sensor circuit, which was a concern when using the dual system, without increasing the circuit size. It becomes possible to detect an open failure of the output wiring.

  The gist of the present invention is that, in the bridge circuit in which a plurality of resistance elements are assembled in a bridge shape as the detection element, the output means is configured to draw out the output wiring from the middle of the resistance pattern of the resistance element. .

  According to this configuration, it is possible to determine the presence or absence of an open failure in the output wiring with a simple configuration by simply pulling out the wiring from the middle of the resistance pattern. The fear of taking is less likely to occur.

  In the present invention, the operation circuit obtains the detection signal output from the detection circuit as one operation input, determines the operation state of the operation unit, and the signal value combination is switched according to the operation state of the operation unit. When it is determined that the output wiring is in an open state by generating the two outputs and outputting the two outputs from the output terminals to the corresponding devices to operate the devices. The gist is to output the two outputs as a combination of abnormality notification signal values.

  According to this configuration, when the output wiring is an open failure, the operating circuit outputs an abnormality notification to the device side. However, if the operating circuit is a one-input two-output circuit, the abnormality notification is, for example, an H level of the signal and It can be expressed by a combination of L levels. Therefore, for example, if the abnormality notification is expressed by changing the pulse period or changing the pulse width, a special oscillation circuit or the like that can satisfy this signal transmission is required in the operating circuit, which may cause complication of the operating circuit. In this case, since there is no concern about this kind of circuit complexity, the circuit structure of the operating circuit is not complicated.

  According to the present invention, it is possible to detect an open failure of a signal line inside a device without enlarging the device size.

An embodiment of a sensor circuit embodying the present invention will be described below with reference to FIGS.
As shown in FIG. 1, a stop lamp (brake lamp) 2 for notifying a subsequent vehicle that a braking operation has been applied to the vehicle 1 is provided at the rear position of the vehicle 1 in the vehicle 1. The stop lamp 2 is composed of, for example, a light bulb, an LED, and the like, and is turned on when the driver depresses the brake pedal 3. When the stop lamp 2 is also used as a tail lamp, when the brake pedal 3 is depressed, the tail lamp is lit with a light quantity several times that of normal times. The brake pedal 3 corresponds to the operation unit.

  The vehicle 1 is equipped with a cruise control system 4 as one driving operation function for the purpose of reducing the driving operation load. Even if the accelerator pedal 5 is not depressed, the cruise control system 4 sets the inter-vehicle distance from the preceding traveling vehicle 6 at the set speed set by the driver giving a speed setting instruction during normal driving. This is a driving system that causes the vehicle 1 to travel at a constant speed while maintaining. The cruise control system 4 is activated when a cruise control selector switch (not shown) provided near the steering wheel in the vehicle is turned on, and a cruise control cancel switch (not shown) is operated or the brake pedal 3 is operated. When it is stepped on, it is released.

  As shown in FIG. 3, the vehicle 1 is provided with an operation determination device 7 as an operation detection system when the operator depresses the brake pedal 3 to operate the stop lamp 2 and the cruise control system 4. The operation determination device 7 is provided with an operation detection unit 8 as an ASSY component in which various electronic components of the operation determination device 7 are assembled. The operation detection unit 8 is provided with a power connector terminal 9 connected to the in-vehicle battery + B, a GND connector terminal 10 connected to GND (ground), and an IG connector terminal 11 connected to an ignition power supply. The operation detection unit 8 includes an S / L connector terminal 13 connected to a stop lamp ECU 12 that is a control unit of the stop lamp 2 via an electric wiring such as a cable, and a cruise control ECU 14 that is a control unit of the cruise control system 4. Similarly, a C / C connector terminal 15 connected via an electric wiring such as a cable is provided. The stop lamp ECU 12 and the cruise control ECU 14 constitute a device, and the S / L connector terminal 13 and the C / C connector terminal 15 constitute an output terminal.

  The operation detection unit 8 is provided with a mold IC 19 in which various IC components of the operation determination device 7 (in this example, a magnetic sensor IC 16 and a control IC 17) are sealed with a resin mold 18 (see FIG. 2). As shown in FIG. 2, the mold IC 19 is attached and fixed to the assembly board 20 of the operation detection unit 8 by soldering at a plurality of locations. As shown in FIG. 3, the mold IC 19 of this example includes a Vbb solder joint 21 connected to the power connector terminal 9, a GND solder joint 22 connected to the GND connector terminal 10, and a VIG solder joint connected to the IG connector terminal 11. Part 23 is provided. The mold IC 19 is provided with a Lout terminal solder joint portion 24 connected to the S / L connector terminal 13 and a Cout terminal solder joint portion 25 connected to the C / C connector terminal 15. The magnetic sensor IC 16 corresponds to a detection circuit, and the control IC 17 constitutes a control circuit and an operation circuit.

  The magnetic sensor IC 16 and the control IC 17 which are IC components of the mold IC 19 are each composed of a single independent IC chip, and are mounted on the IC substrate 26 (see FIG. 2) of the mold IC 19 by wire bonding. In wire bonding, as shown in FIG. 2, the wiring wire 27 is pressed against the bonding destination with a tool (ultrasonic wire bonder) and rubbed with ultrasonic vibration, and the wiring wire 27 is brought to the bonding destination by frictional heat generated at that time. In this bonding method, the wiring wire 27 has one end fixed to the IC component 28 and the other end of the wiring wire 27 fixed to the lead frame 29 of the IC substrate 26.

  As shown in FIG. 4, the magnetic sensor IC 16 is a sensor component that detects a depression operation of the brake pedal 3 magnetically by observing a change in a magnetic field applied from a magnet 30 attached to the brake pedal 3. The magnetic sensor IC 16 of this example is an MRE sensor composed of a plurality of magnetic resistors, and in this example, is composed of a bridge circuit 16a of four magnetic resistors R1 to R4. The magnetic sensor IC 16 determines the potential difference between the intermediate potential between the magnetic resistance R1 and the magnetic resistance R4 and the intermediate potential between the magnetic resistance R2 and the magnetic resistance R3 according to the direction of the magnetic field applied to itself. Is output as a detection signal Sout (see FIG. 3). The magnetic resistances R1 to R4 constitute a detection element and a resistance element, and the magnetic resistance R3 among them corresponds to one detection element.

  As shown in FIG. 4, since the magnetic sensor IC 16 is attached to the IC substrate 26 by wire bonding, the magnetic sensor IC 16 has a plurality of wire bonding portions generated by wire bonding. In this example, the 1st wire junction part 31a connected to the power supply of the operation determination apparatus 7, the 2nd wire junction part 31b connected to GND, and the 3rd wire junction part connected to the intermediate terminal between magnetic resistance R2 and magnetic resistance R3 31c and the 4th wire junction part 31d connected to the intermediate terminal between magnetic resistance R1 and magnetic resistance R4 are formed.

  When the brake pedal 3 is depressed, the direction of the magnet 30 attached to the brake pedal 3 changes with respect to the magnetic sensor IC 16 on the fixed side, so that the magnetic field applied from the magnet 30 to the magnetic sensor IC 16 is changed. The direction changes. When the brake pedal 3 is not operated, the magnetic sensor IC 16 outputs a signal value near “0” as the detection signal Sout as shown in FIG. 5, and the signal value changes to AC as the brake pedal 3 is depressed. A detection signal Sout that increases in waveform is output.

  Further, as shown in FIG. 4, the magnetic sensor IC 16 of the present example is formed so that a divided output Sxo (see FIG. 3) of one of the four magnetic resistors constituting the bridge circuit 16a can be taken out to the outside. In this example, the divided voltage output Sxo of R3 out of the four magnetic resistances R1 to R4 is taken out. The magnetic sensor IC 16 outputs the potential difference between the intermediate potential in the middle of the resistance pattern of the magnetic resistance R3 and the intermediate potential of the magnetic resistance R1 and the magnetic resistance R4 to the control IC 17 as the divided output Sxo. The intermediate potential in the middle of the resistance pattern of the magnetoresistor R3 is taken out by forming an intermediate terminal 32 in the middle of the resistance pattern of the magnetoresistor R3 and pulling out the wiring therefrom as shown in FIG. In the magnetic sensor IC 16, a sensor-side diagnostic wire bonding portion 31e shown in FIG. 4 is formed as a wire bonding bonding portion connected to the intermediate terminal 32 of the magnetic resistance R3. The partial pressure output Sxo corresponds to a comparison output.

  The control IC 17 is an IC component that comprehensively controls the mold IC 19 (that is, the operation determination device 7), and is connected to the magnetic sensor IC 16 via lead frames 33a to 33d on the IC substrate 26 as shown in FIG. Has been. In addition, the control IC 17 of this example also applies to the intermediate terminal 32 of the magnetic resistance R3 via a lead frame (hereinafter referred to as a diag line) 33e so as to see the potential of the intermediate terminal 32 of the magnetic resistance R3 of the bridge circuit 16a. It is connected. The control IC 17 generates two outputs based on the detection signal Sout acquired from the magnetic sensor IC 16 and checks whether or not the output wiring of the magnetic sensor IC 16, that is, the lead frame 33 c is in an open state ( IC component with diagnostic function). The lead frames 33a to 33d constitute wiring, and the signal output line 33c among them corresponds to output wiring.

  The control IC 17 includes an internal power supply 34 that generates a power supply for operating the IC by changing the voltage of the main power supply, two amplification amplifiers 35 and 36 that amplify the input signal to a predetermined value, and output the two input signal values. Two operation comparators 37 and 38 that compare the levels and output an H level or L level signal according to the comparison result are provided. Further, the control IC 17 converts and outputs one input signal as two output signals, and at that time, a logic circuit 39 having a self-diagnosis function as to whether or not the diagnosis line 33e is in an open state, and a switching element in the control IC 17 One transistor 40 and a second transistor 41 are provided.

  Since the control IC 17 is attached to the IC substrate 26 by wire bonding, the control IC 17 has a plurality of wire bonding portions generated by wire bonding in the same manner as the magnetic sensor IC 16. In this example, a fifth wire joint portion 42a connected to the Vbb solder joint portion 21, a sixth wire joint portion 42b connected to the GND solder joint portion 22, and a seventh wire joint portion 42c connected to the VIG solder joint portion 23. An eighth wire joint portion 42d connected to the Lout terminal solder joint portion 24 and a ninth wire joint portion 42e connected to the Cout terminal solder joint portion 25 are formed.

  The control IC 17 is connected to the magnetic sensor IC 16 via the tenth to thirteenth wire joint portions 44a to 44d and the control-side diagnostic wire joint portion 44e generated by wire bonding. Specifically, in the control IC 17, the tenth wire bonding portion 44a is connected to the first wire bonding portion 31a of the magnetic sensor IC 16 via the lead frame 33a, and the eleventh wire bonding portion 44b is connected to the magnetic sensor via the lead frame 33b. A twelfth wire bonding portion 44c is connected to the second wire bonding portion 31b of the IC 16 and a thirteenth wire bonding portion is connected to the third wire bonding portion 31c of the magnetic sensor IC 16 via a lead frame (hereinafter referred to as a signal output line) 33c. The part 44d is connected to the fourth wire joint 31d of the magnetic sensor IC 16 via the lead frame 33d, and the control side diagnostic wire joint 44e is connected to the sensor side diagnostic wire joint 31e of the magnetic sensor IC 16 via the diagnosis line 33e. ing. The wire joint portions 31e and 44e and the intermediate terminal 32 constitute an extraction means.

  In the internal power supply 34, the + side terminal is connected to the fifth wire joint portion 42a, and the − side terminal is connected to the tenth wire joint portion 44a. For this reason, in addition to supplying the IC operating power to the control IC 17, the internal power supply 34 of the present example has its own negative terminal connected to the magnetic sensor IC 16, so that the magnetic sensor IC 16 also operates during operation. By supplying a current, the IC sensor power supply is also supplied to the magnetic sensor IC 16. Two resistors 45 and 46 are connected in series between the negative terminal of the internal power supply 34 (the tenth wire bonding portion 44a) and the sixth wire bonding portion 42b. In this example, the high potential side of the internal power supply 34 is used. The first resistor 45 and the second resistor 46 are in order.

  The first amplification amplifier 35 has a positive input terminal connected to the twelfth wire joint 44 c, a negative input terminal connected to the thirteenth wire joint 44 d, and an output terminal of the first operation comparator 37. Connected to the + side input terminal. Therefore, in the first amplification amplifier 35, the positive input terminal of the two input terminals is connected to the intermediate terminal of the magnetic resistance R2 and the magnetic resistance R3 of the magnetic sensor IC16, and the negative input terminal is the magnetic resistance R1 of the magnetic sensor IC16. And a connection state connected to the intermediate terminal of the magnetic resistance R4. Therefore, the first amplification amplifier 35 receives the detection signal Sout from the magnetic sensor IC 16, amplifies the detection signal Sout to a predetermined value, and outputs it to the first operation comparator 37.

  In the second amplification amplifier 36, the positive input terminal of the two input terminals is connected to the control-side diagnostic wire joint 44e, the negative input terminal is connected to the thirteenth wire joint 44d, and the output terminal is the second operation comparator 38. Is connected to the + side input terminal. Therefore, in the second amplification amplifier 36, the positive input terminal of the two input terminals is connected to the intermediate terminal 32 of the magnetic resistance R3 of the magnetic sensor IC 16, and the negative input terminal is connected to the magnetic resistance R1 and the magnetic resistance of the magnetic sensor IC 16. The connection state connected to the intermediate terminal of the resistor R4 is taken. Therefore, the second amplification amplifier 36 receives the partial pressure output Sxo from the magnetic sensor IC 16, amplifies the partial pressure output Sxo to a predetermined value, and outputs the amplified value to the second operation comparator 38.

  The first operation comparator 37 has a negative input terminal of two input terminals connected to an intermediate position between the first resistor 45 and the second resistor 46, and an output terminal connected to the logic circuit 39. When the first amplifier output Vamp1 of the first amplification amplifier 35 input at the + side input terminal is higher than the reference potential input at the − side input terminal, the first operation comparator 37 outputs an H level signal as the first comparator output Vcmp1. Is output to the logic circuit 39. On the other hand, if the first amplifier output Vamp1 of the first amplifier 35 is lower than the reference potential, an L level signal is output to the logic circuit 39 as the first comparator output Vcmp1.

  The second operation comparator 38 has a negative input terminal of two input terminals connected to an intermediate position between the first resistor 45 and the second resistor 46, and an output terminal connected to the logic circuit 39. If the second amplifier output Vamp2 of the second amplification amplifier 36 input at the − side input terminal is higher than the reference potential input at the − side input terminal, the second operation comparator 38 outputs an H level signal as the second comparator output Vcmp2. Is output to the logic circuit 39. On the other hand, if the second amplifier output Vamp2 of the second amplification amplifier 36 is lower than the reference potential, an L level signal is output to the logic circuit 39 as the second comparator output Vcmp2.

  Incidentally, the amplifier output Vamp1 of the first amplification amplifier 35, which is the input potential of the first operation comparator 37, corresponds to the voltage generated in the magnetic resistance R3 in the bridge circuit 16a of the magnetic sensor IC 16, whereas the second operation comparator 38. The amplifier output Vamp2 of the second amplifying amplifier 36, which is the input potential, corresponds to a voltage generated in a part of the magnetic resistance R3. Therefore, when comparing these amplifier outputs Vamp1 and Vamp2, the amplifier output Vamp1 of the first amplification amplifier 35 takes a higher value than the amplifier output Vamp2 of the second amplification amplifier 36. For this reason, when the brake pedal 3 is depressed and the detection signal Sout of the magnetic sensor IC 16 increases, the input potential of the first operating comparator 37 exceeds the reference potential before the second operating comparator 38. In this case, first, the first operation comparator 37 is operated first, and then the second operation comparator 38 starts operation with a predetermined time difference.

  The logic circuit 39 is a combination of various logic circuit groups such as an AND circuit and an OR circuit, and its output terminal is connected to the base terminal of the first transistor 40 and the gate terminal of the second transistor 41. . Further, the logic circuit 39 of the present example is configured so that the rectangular wave signal Vout (see FIG. 3) output from each of the S / L connector terminal 13 and the C / C connector terminal 15 depends on whether or not the brake pedal 3 is depressed. Thus, the HL level is switched and output. In this example, as shown in the truth table 47 of FIG. 7, when the brake pedal 3 is not depressed, the C / C connector terminal outputs an L level signal from the S / L connector terminal 13. 15 can output an H level signal, and when the brake pedal 3 is depressed, an H level signal can be output from the S / L connector terminal 13 and an L level signal can be output from the C / C connector terminal 15. is there. The rectangular wave signal Vout corresponds to the output signal.

  The first transistor 40 is an npn-type transistor in this example, and has an emitter terminal connected to the sixth wire joint 42b (GND solder joint 22) and a collector terminal connected to the eighth wire joint 42d (Lout terminal solder joint). 24). In addition, the second transistor 41 is composed of, for example, a MOSFET in this example, the drain terminal is connected to the seventh wire joint 42c (VIG solder joint 23), and the source terminal is the ninth wire joint 42e (Cout terminal solder joint). 25).

  As shown in FIG. 3, the operation detection unit 8 is provided with a third transistor 48 between the Lout terminal solder joint 24 and the S / L connector terminal 13. The third transistor 48 has an emitter terminal connected to the power connector terminal 9, a collector terminal connected to the S / L connector terminal 13, and a base terminal connected to the Lout terminal solder joint 24. A third resistor 49 for overvoltage protection is connected between the emitter terminal of the third transistor 48 and the power connector terminal 9. A similar fourth resistor 50 for overvoltage protection is also connected between the collector terminal of the third transistor 48 and the S / L connector terminal 13. Between an intermediate position between the collector terminal of the third transistor 48 and the fourth resistor 50 and the GND connector terminal 10, a first capacitor 51 capable of removing noise that may occur in the electric circuit of the operation detection unit 8, and GND A diode 52 for preventing a reverse current from the side is connected in series.

  A fifth resistor 53 for overvoltage protection is connected between the IG connector terminal 11 and the VIG solder joint 23. Between the intermediate position between the VIG solder joint 23 and the fifth resistor 53 and the intermediate position between the first capacitor 51 and the diode 52, a pair capable of removing noise that may occur in the electric circuit of the operation detection unit 8. The second capacitor 54 and the third capacitor 55 are connected in series. A sixth resistor 56 for overvoltage protection is connected between the C / C connector terminal 15 and the Cout terminal solder joint 25. A fourth capacitor 57 for noise removal is also connected between an intermediate position between the Cout terminal solder joint 25 and the sixth resistor 56 and an intermediate position between the first capacitor 51 and the diode 52. A similar fifth capacitor 58 and sixth capacitor 59 for noise removal are connected in series between the intermediate position between the power connector terminal 9 and the third transistor 48 and the intermediate position between the GND solder joint 22 and the diode 52. Connected in line.

  Based on the detection signal Sout obtained from the magnetic sensor IC 16, the control IC 17 operates one of the stop lamp 2 and the cruise control system 4 and stops the other. When the brake pedal 3 is not operated, the control IC 17 of this example outputs an L level signal from the S / L connector terminal 13 to the stop lamp ECU 12 to turn off the stop lamp 2 and from the C / C connector terminal 15. An H level signal is output to the cruise control ECU 14 to make the cruise control system 4 operable. In addition, when the brake pedal 3 is operated, the control IC 17 outputs an H level signal from the S / L connector terminal 13 to the stop lamp ECU 12 to light the stop lamp 2, and from the C / C connector terminal 15 to the L level. A signal is output to the cruise control ECU 14 to bring the cruise control system 4 into an operation release state.

  When the logic circuit 39 generates two outputs based on the detection signal Sout of the magnetic sensor IC 16 as described above, the logic IC 39 uses the partial pressure output Sxo obtained from the magnetic sensor IC 16 to control the control IC 17 (that is, the operation determination device 7). This is a circuit having a self-diagnosis function for checking whether the output is normal. The logic circuit 39 in this example is a circuit for checking whether or not the signal output line 33c is in an open state due to the signal output line 33c between the magnetic sensor IC 16 and the control IC 17 being peeled off at the wire bonding portion. When it is recognized that the signal output line 33c is in an open state, an L level signal is output from both the S / L connector terminal 13 and the C / C connector terminal 15 to notify other devices of this fact.

  For example, when making the stop lamp ECU 12 determine and recognize the presence or absence of an open failure of the signal output line 33c, this type of stop lamp ECU 12 is connected to the S / L connector terminal 13 and the C / C via electrical wiring such as the already described cables. It is connected to both of the connector terminals 15. When the stop lamp ECU 12 having such a failure presence / absence recognition function receives an L level signal from both the S / L connector terminal 13 and the C / C connector terminal 15, the operation determination device 7 (control IC 17) is input with this signal input. For example, the operation determination device 7 is forcibly terminated or the user is notified of this.

Next, the operation of the operation determination device 7 of this example will be described using the truth table 47 of FIG.
When the operator does not depress the brake pedal 3, the magnetic sensor IC 16 takes a signal output state in which the low-potential detection signal Sout and the partial pressure output Sxo are output, and therefore the first amplification for inputting the detection signal Sout. The amplifier 35 and the second amplification amplifier 36 that receives the divided voltage output Sxo both output an L level signal. At this time, since the first operation comparator 37 does not take a state of obtaining a high-potential output signal from the first amplification amplifier 35, the first operation comparator 37 outputs an L level signal as the first comparator output Vcmp1 to the logic circuit 39, and performs the second operation. Similarly, the comparator 38 outputs an L level signal to the logic circuit 39 as the second comparator output Vcmp2. Therefore, the logic circuit 39 turns off the first transistor 40 and turns on the second transistor 41 by inputting the L level signal from the two operation comparators 37 and 38.

  In the control IC 17, since the first transistor 40 is in the off state, the output of the Lout terminal solder joint 24 is in a high impedance (Hi-Z) state, while the second transistor 41 is in the on state. Therefore, the Cout terminal solder joint 25 changes to high impedance and outputs an H level signal. As described above, when the output of the Lout terminal solder joint 24 is in a high impedance state, the third transistor 48 is maintained in an OFF state. Accordingly, the operation detection unit 8 outputs an L level signal from the S / L connector terminal 13 to the stop lamp ECU 12 and outputs an H level signal from the C / C connector terminal 15 to the cruise control ECU 14.

  When the stop lamp ECU 12 receives an L level signal from the S / L connector terminal 13 of the operation detection unit 8, the stop lamp ECU 12 turns off the stop lamp 2. On the other hand, when the cruise control ECU 14 inputs an H level signal from the C / C connector terminal 15 of the operation detection unit 8, the cruise control system 14 makes the operation mode of the cruise control system 4 operable. When it is detected that the cruise control selector switch is operated under this condition, the cruise control ECU 14 in which the operation mode is operable is activated to activate the cruise control system 4 and operate the system.

  Subsequently, when the brake pedal 3 is depressed, the detection output of the magnetic sensor IC 16, that is, the detection signal Sout and the partial pressure output Sxo of the magnetic sensor IC 16 gradually increase with the depression. Along with this, the values of the first amplifier output Vamp1 of the first amplification amplifier 35 and the second amplifier output Vamp2 of the second amplification amplifier 36 gradually increase. When the first amplifier output Vamp1 of the first amplification amplifier 35 is compared with the second amplifier output Vamp2 of the second amplification amplifier 36, the first amplifier output Vamp1 is entangled with the entire magnetic resistance R3. On the other hand, since the second amplifier output Vamp2 is a partial resistance of the magnetic resistance R3 with respect to the output, the first amplifier output Vamp1 is always higher than the second amplifier output Vamp2 as shown in FIG.

  If the first amplifier output Vamp1 exceeds the reference potential of the first operation comparator 37 while the brake pedal 3 is being depressed, the first operation comparator 37 is activated, and the first operation comparator 37 is set as the first comparator output Vcmp1. It outputs until now, changes to the L level signal, and outputs the H level signal. However, when the input potentials of the first operation comparator 37 and the second operation comparator 38 are compared, the input potential of the second operation comparator 38 is higher than the input potential of the first operation comparator 37. When the comparator 37 starts operation, the second operation comparator 38 has not yet started operation.

  Then, when the driver further depresses the brake pedal 3, the input potential of the second operation comparator 38 after the first operation comparator 37 also exceeds the reference potential, and the second operation comparator 38 outputs the second comparator output. Instead of the L level signal that has been output as Vcmp2, the H level signal is output at this timing. That is, when the brake pedal 3 is depressed, the first operation comparator 37 starts operating prior to the second operation comparator 38, and after the first operation comparator 37 is operated, the second operation comparator 37 has a time difference. 38 is activated.

  When both the first operation comparator 37 and the second operation comparator 38 are activated and output an H level signal, the logic circuit 39 turns on the first transistor 40 and turns off the second transistor 41. Since the first transistor 40 is in the ON state, the control IC 17 outputs an L level signal from the Lout terminal solder joint 24 to a high impedance, while the second transistor 41 is in the OFF state. Therefore, the output of the Cout terminal solder joint 25 is in a high impedance state. As described above, when the output of the Lout terminal solder joint 24 takes the L level signal, the operation state of the third transistor 48 is switched from the off state to the on state. Accordingly, the operation detection unit 8 outputs an H level signal from the S / L connector terminal 13 to the stop lamp ECU 12 and outputs an L level signal from the C / C connector terminal 15 to the cruise control ECU 14.

  When the stop lamp ECU 12 receives an H level signal from the S / L connector terminal 13 of the operation detection unit 8, the stop lamp ECU 12 turns on the stop lamp 2. On the other hand, when the cruise control ECU 14 inputs an L level signal from the C / C connector terminal 15 of the operation detection unit 8, the cruise control system 14 cancels the operation mode of the cruise control system 4 that has been operable until then, and the cruise control system 4 Stop.

  Here, for example, the signal output line 33c, which is a signal line of the detection output of the magnetic sensor IC 16, is generated by the IC (the magnetic sensor IC 16 and the control IC 17) due to the severe use environment of the operation determination device 7 or long-term use. It is also conceivable that the signal output line 33c is in an open state as shown in FIG. 9 due to peeling at the joint portion (that is, the wire joint portions 31c and 44c). When the signal output line 33c is in the open state, the control IC 17 cannot obtain the detection signal Sout from the magnetic sensor IC 16, and the control IC 17 and the operation determination device 7 output normal output signals to the stop lamp ECU 12 and the cruise control ECU 14. A problem arises that makes it impossible to do so. Under this situation, there are problems such as the stop lamp 2 does not light or the cruise control system 4 in the activated state is not released even though the brake pedal 3 is depressed. Under the open failure of the signal output line 33c, countermeasures such as stopping the operation of these systems are required.

  Therefore, looking at the state when the signal output line 33c is in the open state, the detection signal Sout of the magnetic sensor IC 16 does not reach the control IC 17, but the magnetic sensor IC 16 is connected to the control IC 17 via the diagnosis line 33e. Therefore, the divided voltage output Sxo of the magnetic resistance R3 in the magnetic sensor IC16 reaches the control IC17. Therefore, when the relationship between the signal values of the first amplifier output Vamp1 that is the amplified signal of the detection signal Sout and the second amplifier output Vamp2 that is the amplified signal of the divided voltage output Sxo is seen, this is as shown in FIG. The second amplifier output Vamp2 takes a higher value than the first amplifier output Vamp1.

  As shown in the truth table 47 of FIG. 7, when the logic circuit 39 inputs the L level signal as the first comparator output Vcmp1 and the H level signal as the second comparator output Vcmp2, the signal input of this combination Thus, the first transistor 40 and the second transistor 41 are both turned off. For this reason, in the control IC 17, the outputs of both the Lout terminal solder joint portion 24 and the Cout terminal solder joint portion 25 are in a high impedance state. Therefore, the operation detection unit 8 outputs an L level signal from the S / L connector terminal 13 to the stop lamp ECU 12 and also outputs an L level signal from the C / C connector terminal 15.

  By the way, the stop lamp ECU 12 of this example determines whether there is an open failure in the signal output line 33c by looking at the signal combination of the signal values acquired from the S / L connector terminal 13 and the C / C connector terminal 15 of the operation detection unit 8. Has a function to determine whether there is a failure. The stop lamp ECU 12 receives the signal output from the S / L connector terminal 13 and the C / C connector terminal 15 of the operation detection unit 8, both of which are H level signals, or one is an H level signal and the other is an L level signal. If there is, the signal output line 33c is recognized as not having an open failure. On the other hand, when the stop lamp ECU 12 receives the L level signal from both the S / L connector terminal 13 and the C / C connector terminal 15, it recognizes that the signal output line 33c has an open failure with this signal input, and operates the operation. A corresponding action is taken such as forcibly terminating the operation of the determination device 7 or notifying the user to that effect.

  Therefore, in the present example, a diagnostic line 33e is formed on the magnetic sensor IC 16 for detecting whether or not the brake pedal 3 is depressed, and an intermediate output is extracted from the resistance pattern of the magnetic resistance R3, and obtained from the diagnostic line 33e. The control IC 17 (that is, the operation determination device 7) self-diagnose the presence or absence of an open failure of the signal output line 33c by a method of comparing the partial pressure output Sxo and the detection signal Sout of the magnetic sensor IC16. For this reason, when the control IC 17 performs self-diagnosis on the presence or absence of an open failure in the signal output line 33c, it is necessary to use a dual system in which two sets of bridge circuits 16a are provided in the magnetic sensor IC 16 to perform the presence / absence diagnosis on the signal output line 33c It will be over. Therefore, it is possible to determine the presence or absence of an open failure in the signal output line 33c without causing an increase in the size of the apparatus, which is a concern when this type of duplex system is used.

  Further, the self-diagnosis function of the control IC 17 of this example is a diagnosis function for checking whether or not the H level signal is normally output from the first operation comparator 37 when the brake pedal 3 is depressed. Therefore, the self-diagnosis function of the control IC 17 is a function that does not operate when the brake pedal 3 is not depressed, and starts operation when the brake pedal 3 is depressed and performs self-diagnosis. Therefore, a self-diagnosis function for performing self-diagnosis when the signal of the magnetic sensor IC 16 is output (when the H level signal of the first operation comparator 37 is output), that is, when the terminal signal 1 output is ON (when the S / L connector terminal output is ON). It can be said that.

  By the way, the depression operation of the brake pedal 3 is an operation that is performed evenly during traveling, and the period when the brake pedal 3 is not operated is overwhelmingly longer. Therefore, for example, when the self-diagnosis function of the control IC 17 is operated even when the brake pedal 3 is not depressed, for example, if the control IC 17 breaks down and the self-diagnosis function operates under this failure, an error occurs. When it becomes a situation where an output can be output, there is a concern that the control IC 17 may fall into a situation where it malfunctions due to this. However, since the self-diagnosis function of this example performs self-diagnosis only when one output is turned on when the brake pedal is depressed, a situation in which the control IC 17 is not adversely affected due to a failure of the self-diagnosis function is less likely to occur. Therefore, it can be said that the effect is high.

  Further, when comparing the input potential of the first operation comparator 37 with the input potential of the second operation comparator 38, the input potential of the second operation comparator 38 is an intermediate potential of the magnetic resistance R3. 38, even if the reference potential is the same, when the value of the detection signal Sout increases, the first operating comparator 37 is in an operating state in which it moves ahead of the second operating comparator 38. By the way, when considering the case where the second operation comparator 38 of the present example having the self-diagnosis function starts operating before the first operation comparator 37, at this time, the self-diagnosis function of the control IC 17 is made to perform the empty diagnosis. However, in this example, since the second operation comparator 38 starts operating after the first operation comparator 37 is activated, the self-diagnosis function is started. Such concerns do not arise.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) The voltage output is taken out from the middle of the magnetic resistance R3, which is one magnetic resistance of the bridge circuit of the magnetic sensor IC 16, and the control IC 17 compares the divided output Sxo with the actual detection signal Sout of the magnetic sensor IC 16. Thus, the self-diagnosis of the open failure of the signal output line 33c is performed. For this reason, it is not necessary to use a double system in which two sets of bridge circuits 16a are incorporated in the magnetic sensor IC 16 to perform open failure determination, so that the signal output line 33c can be opened without increasing the circuit size (device size). Self-diagnosis of failure can be performed.

  (2) When performing self-diagnosis on the presence or absence of an open failure in the signal output line 33c, in this example, the signal output line 33c is opened with a simple configuration in which the wiring is drawn from the middle position of the resistance pattern of the magnetic resistance R3 to extract the intermediate potential. A self-diagnosis is performed for failure. Therefore, when performing this type of self-diagnosis, the circuit configuration (device configuration) of the operation determination device 7 is not complicated.

  (3) The operation determination device 7 of the present example generates two outputs based on one input obtained from the magnetic sensor IC 16, and supplies each of these outputs to the stop lamp ECU 12 and the cruise control ECU 14, thereby providing a stop lamp. 2 and a 1-input 2-output type sensor circuit that operates the cruise control system 4. Therefore, when a notification that there is a failure is expressed by this type of sensor circuit, this can be expressed by a combination of two output signal levels. For this reason, for example, if this type of failure notification is to be expressed by changing the pulse period or pulse width of the output signal, a special transmission circuit or the like is required to do this, and the control IC 17 becomes complicated. Alternatively, there is a concern that the cost of parts increases, but in the case of this example, this kind of special circuit part is unnecessary, so that a notification of failure can be expressed with a simple and low-cost circuit structure.

  (4) The self-diagnosis function of this example is a function for self-diagnosis whether the lead frame (signal output line 33c) connecting the magnetic sensor IC 16 mounted on the IC substrate 26 and the control IC 17 is in an open state. Therefore, since this type of IC circuit has an attachment state in which the connection terminal portion is bonded to the IC substrate 26 by wire bonding or the like, the problem of peeling at the bonded portion inevitably becomes a concern. Adopting the self-diagnosis function of this example for this IC circuit is also highly effective from this viewpoint.

  (5) Since the input potential of the second operation comparator 38 is the intermediate potential of the magnetic resistance R3, these operation comparators 37 and 38 have the first operation when the value of the detection signal Sout increases even if the reference potential is the same. The operation state in which the comparator 37 moves prior to the second operation comparator 38 is taken. For this reason, it is difficult for a situation in which the self-diagnosis function of the control IC 17 performs a null diagnosis, and the operation reliability of the self-diagnosis function is high.

  (6) When checking whether or not the signal output line 33c is in the open state, the potential drawn from the middle of the magnetic resistance R3 is used. For this reason, even if the value of the detection signal Sout fluctuates due to disturbance, for example, when the signal output line 33c is not open, the divided voltage output Sxo drawn from the middle of the magnetic resistance R3 fluctuates in the same way as the detection signal Sout. Since the waveform is taken, it is difficult for the divided voltage output Sxo to exceed the detection signal Sout due to disturbance or the like when the signal output line is normal, and it is possible to detect the presence or absence of an open failure in the signal output line 33c with high accuracy. .

  (7) The self-diagnosis function of this example controls the magnetic sensor IC 16 when the brake pedal 3 is depressed and the first operation comparator 37 outputs an H level signal when looking at an open failure of the signal output line 33c. This is a diagnosis for checking whether or not the signal output line 33c connecting the IC 17 has an open failure. That is, when the brake pedal 3 is depressed and the first operation comparator 37 outputs the H level signal when the H level signal is output (when one output is on), the self-diagnosis function of the control IC 17 starts to operate, Self-diagnosis of open failure of the signal output line 33c is performed. Therefore, since the self-diagnosis mechanism does not operate when the brake pedal 3 is not depressed, it is difficult to cause a situation where the control IC 17 is adversely affected due to a failure of the self-diagnosis function when the brake pedal is not operated. it can.

  (8) The magnetic sensor IC 16 and the control IC 17 are formed as a mold IC 19, that is, as one component, by sealing these ICs with resin. Therefore, when assembling this type of IC system component at the assembly destination, only the operation of assembling the mold IC 19 is sufficient, so that the assembling operation can be simplified.

In addition, embodiment is not limited to the structure until now, You may change into the following aspects.
The magnetic resistance for extracting the divided voltage output Sxo is not necessarily limited to R3, and any of the other magnetic resistances R1, R2, and R4 may be used.

  The circuit configuration of the logic circuit 39 is not particularly limited as long as it can output a signal combination that can operate the operation target of the operation determination device 7 (in this example, the stop lamp 2 and the cruise control system 4). .

  The configuration for drawing out the potential of the magnetic resistance R3 from the middle is not limited to the configuration in which the intermediate terminal 32 is provided in the middle of the resistance pattern and the potential is drawn from there. For example, it is possible to attach a resistance element in series with the magnetic resistance R3 that originally exists, and take out the potential between the resistance elements as the divided output Sxo.

  -The sensor component which detects the depression amount of the brake pedal 3 is not necessarily limited to a magnetic sensor, For example, you may employ | adopt other sensor components, such as an optical sensor and a pressure sensor.

  The signal values output from the S / L connector terminal 13 and the C / C connector terminal 15 of the operation detection unit 8 when the self-diagnostic function determines that there is an open failure and the failure are both limited to L level signals. However, depending on the combination of output signals at the time of operation of the apparatus, both of them may be H level signals.

The operation start timing of the self-diagnosis function is not necessarily limited to the time after the first operation comparator 37 is activated, and may be the same timing.
-The self-diagnosis function is not necessarily performed during the period when the brake pedal 3 is depressed, that is, the first operation comparator 37 outputs the H level signal, but the brake pedal 3 is depressed. It may be carried out even when there is not.

  The failure presence / absence determination function is not necessarily limited to that of the stop lamp ECU 12, but may be included in the cruise control ECU 14, or a determination-dedicated ECU may be separately provided and determined.

  The operation determination device 7 is not limited to a device that detects whether or not the brake pedal 3 is depressed and activates the stop lamp 2 and the cruise control system 4 according to the depression operation. That is, the mounting target is not particularly limited as long as these two devices are operated by outputting a signal to at least two devices for one operation of the operation unit.

  The operation determination device 7 is not necessarily limited to being a 1-input 2-output type sensor circuit. For example, 1-input 1-output capable of outputting an output signal having a pulse waveform corresponding to the input value for 1-input. It may be a sensor circuit of the type.

Next, technical ideas that can be grasped from the above-described embodiment and other examples will be described below together with their effects.
(1) In any one of claims 1 to 3, the detection circuit and the control circuit are each formed as an independent chip, and the chip is mounted on a substrate, and these are connected via the output wiring. Connected to each other. According to this configuration, when the chip-shaped detection circuit and the control circuit are electrically connected, a manufacturing process for mounting another wiring component such as wire bonding on the substrate is required. The concern that the output wiring will be in an open state must be taken into consideration when attaching a separate wiring component. Therefore, mounting a self-diagnosis function for checking the presence or absence of an open failure of the output wiring on the sensor circuit that mounts the chip-shaped detection circuit and control circuit on the substrate is highly effective from this viewpoint.

  (2) In any one of Claim 3 and the technical idea (1), the operation circuit compares the detection signal obtained from the detection circuit with a reference value and outputs a level signal corresponding to the level. A signal obtained from the two comparison circuits, comprising: a first comparison circuit that compares the output for comparison with the reference value extracted from the extraction means, and a second comparison circuit that outputs a level signal corresponding to the level of the comparison. Based on the above, the presence or absence of an open fault in the output wiring is determined. In this case, when determining whether there is an open failure in the output wiring line, it is only necessary to determine whether the signal level is H level or L level. The determination can be performed with a simple process.

The perspective view of the vehicle which shows the specific example of the vehicle-mounted components in one Embodiment. The model explanatory drawing which shows the wire joint part and solder joint part of IC component. The circuit diagram which shows the electric constitution of the operation determination apparatus. The circuit diagram which shows the electric constitution of mold IC. The wave form diagram of the detection signal which magnetic sensor IC outputs. The schematic diagram which shows the outline of the resistance pattern of one magnetoresistive which comprises a bridge circuit. Truth table of signal combinations output by the operation detection unit. The wave form diagram which shows the brake pedal depression change of the amplification amplifier output at the time of normal. The circuit diagram at the time of the open failure of the signal output line of magnetic sensor IC. The wave form diagram which shows the brake pedal depression change of the amplification amplifier output at the time of abnormality. The schematic block diagram of the operation determination apparatus in the past.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 3 ... Brake pedal as an operation part, 12 ... Stop lamp ECU which comprises apparatus, 13 ... S / L connector terminal which comprises output terminal, 14 ... Cruise control ECU which comprises apparatus, 15 ... C which comprises output terminal / C connector terminal, 16 ... magnetic sensor IC as a detection circuit, 16a ... bridge circuit, 17 ... control IC constituting control circuit and operation circuit, 31e, 44e ... wire joint part constituting take-out means, 32 ... take-out means Intermediate terminals 33a to 33d, lead frames constituting wirings, 33c, signal output lines as output wirings, R3, magnetoresistors constituting one detecting element and resistance elements, R1, R2, R4, detecting elements And magnetoresistive elements constituting the resistance element, Sout ... detection signal, Sxo ... divided voltage output as comparison output, Vout ... rectangular wave signal as output signal issue.

Claims (3)

A control circuit connected to the detection circuit via a wiring detects an operation of the operation unit by an operator, and a detection signal obtained from the detection circuit is output as an output signal corresponding to the operation of the operation unit. In the sensor circuit that operates the device by outputting to
Extraction means for extracting a part of the output as a comparison output from one detection element which is a detection part of the detection circuit;
In the process of converting the detection signal of the detection circuit and outputting it as the output signal, by comparing the detection signal of the detection circuit with the output for comparison obtained from the extraction means, A self-diagnosis function that determines whether there is an open failure whether or not the output wiring is attached to the attachment destination, and outputs a signal that can be notified as such when the output wiring is in the open state A sensor circuit comprising:   2. The output circuit according to claim 1, wherein in the bridge circuit in which a plurality of resistance elements are assembled in a bridge shape as the detection element, the output unit is configured to draw out the output wiring from the middle of the resistance pattern of the resistance element. The sensor circuit described.   The operation circuit obtains the detection signal output from the detection circuit as one operation input, determines an operation state of the operation unit, and generates two outputs in which signal value combinations are switched according to the operation state of the operation unit. However, when the two outputs are output from the output terminals to the corresponding devices, respectively, the device is operated by one input and two outputs, and when the output wiring is determined to be open, the two outputs The sensor circuit according to claim 1 or 2, wherein a signal value combination of abnormality notification is output.

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