JP2009063471A - Sensor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor device capable of improving the versatility by appropriately customizing a detecting range, a response frequency range, or the like. <P>SOLUTION: A demanding signal for adjusting the sensor output characteristic from the outside is input to the sensor device 1 having predetermined sensor output characteristics, and the sensor output characteristics to be included in the sensor device 1 are adjusted according to the installation place and application of the sensor device 1. Thus, even when a plurality of sensor systems 1 having common sensor output characteristics are manufactured, the sensor output characteristics according to various vehicle types, application, and mounting position can be set to each sensor device 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sensor device in which a detection range or the like is adjusted according to an external request.

  Conventionally, for example, Patent Document 1 proposes an acceleration sensor used in an ABS or an airbag system in a vehicle. Specifically, in Patent Document 1, an acceleration transducer that outputs a voltage signal corresponding to detected acceleration, a first filter that passes a component in a certain frequency band of the voltage signal, and a first filter of the voltage signal There has been proposed an acceleration sensor including a second filter that passes a component in a frequency band different from, and output voltage adjusting means that adjusts the level of each voltage signal obtained through the first and second filters.

In such an acceleration sensor, the band pass characteristics of the first filter and the second filter are adjusted, and the level of each voltage signal obtained through each filter is adjusted by the output voltage adjusting means. One response frequency range characteristic detection signal or a plurality of detection signals having different response frequency range characteristics can be acquired with respect to the outputs of two acceleration transducers.
JP-A-10-282136

  However, in the above-described conventional technology, an acceleration sensor is output so that a signal in a detection range, a response frequency range, or the like suitable for these situations is output depending on the vehicle type and location where the acceleration sensor is installed, and the use of the acceleration sensor. It was necessary to prepare variations such as a detection range and a response frequency range in advance.

  Therefore, in order to use the acceleration sensor in various situations, it is necessary to provide the acceleration sensor with a number of variations such as a detection range and a response frequency range in advance, which means that the circuit scale is increased and the output system is increased. Problems arise. In this case, since it is necessary to previously integrate variations such as a necessary detection range and response frequency range into the acceleration sensor, the acceleration sensor cannot be used for other applications.

  An object of this invention is to provide the sensor apparatus which can improve versatility by customizing a detection range, a response frequency range, etc. suitably in view of the said point.

  In order to achieve the above object, the present invention detects a physical quantity and outputs a detection signal corresponding to the physical quantity, and inputs the detection signal from the detection element (40) and processes the detection signal. A sensor circuit unit (50) for processing a detection signal in accordance with a first sensor output characteristic serving as a parameter for the purpose, and a communication unit (10) for extracting a second sensor output characteristic included in a request signal input from the outside. And a control unit (30) for inputting the second sensor output characteristic from the communication unit (10) and adjusting the first sensor output characteristic of the sensor circuit unit (50) to the second sensor output characteristic. It is characterized by that.

  Thereby, even if the first sensor output characteristic is set in the sensor device in advance, the second sensor output characteristic corresponding to the situation in which the sensor device is used can be obtained by inputting the request signal to the sensor device from the outside. Can be set. Therefore, even if a plurality of sensor devices having the common first sensor output characteristics are manufactured, the second sensor output characteristics according to the application of the sensor device can be set later, thereby increasing the versatility of the sensor device. be able to.

  Thus, since the sensor device can be changed to specifications according to the application, there is no need to provide the sensor device with various variations and multiple output systems as in the past, and there is no need to perform circuit design of various variations. There is no need to increase the circuit scale. That is, the sensor device can be manufactured at low cost, and the sensor device can be installed in a small space.

  In such a sensor device, the sensor circuit unit (50) includes an amplifier circuit (52) in which the detection range of the detection element (40) is set as the first sensor output characteristic, and the request signal includes When the detection range in the amplifier circuit (52) is included as the second sensor output characteristic, the control unit (30) detects the detection range in the amplifier circuit (52) as the second sensor output characteristic included in the request signal. Can be adjusted to range.

  In this manner, the detection range in the amplifier circuit (52) can be adjusted. Here, the detection range can be adjusted as the amplification factor of the detection element (40). That is, the detection range (sensitivity) of the detection element (40) can be adjusted by adjusting the amplification factor of the amplifier circuit (52).

  The sensor circuit unit (50) includes an amplifier circuit (52) in which the offset value of the detection signal is set as the first sensor output characteristic, and the amplifier circuit (52 as the second sensor output characteristic in the request signal). ) Is included, the control unit (30) can adjust the offset value in the amplifier circuit (52) to the offset value as the second sensor output characteristic included in the request signal.

  Thus, the offset value of the detection signal in the amplifier circuit (52) can be adjusted. In this case, for example, the offset value can be adjusted by changing the resistance value of the resistor (52d) for adjusting the reference potential of the operational amplifier (52b) constituting the amplifier circuit (52).

  The sensor circuit unit (50) includes a filter circuit (53) in which a response frequency range that allows only a component in a desired frequency band to pass in the detection signal is set as a first sensor output characteristic. When the response frequency range of the filter circuit (53) is included as the second sensor output characteristic, the control unit (30) uses the response frequency range of the filter circuit (53) as the second sensor output characteristic included in the request signal. Can be adjusted to the response frequency range.

  Thus, the response frequency range of the filter circuit (53) can also be adjusted. In this case, in order to adjust the response frequency range, the resistance value of the resistor (53d) constituting the filter circuit (53), the capacitance value of the capacitor (53c), etc. may be adjusted.

  The sensor circuit unit (50) is A / D converted by the A / D conversion unit (54) for A / D converting the detection signal and the A / D conversion unit (54) as the first sensor output characteristic. And a signal processing unit (55) in which an output offset determination value for determining whether or not the detection signal is within a certain range is set, and a signal processing unit ( 55), the control unit (30) converts the output offset determination value of the signal processing unit (55) into the output offset determination value as the second sensor output characteristic included in the request signal. Can be adjusted.

  As described above, when the detection signal as the A / D converted digital signal is processed by the signal processing unit (55), the output offset determination value can be adjusted.

  In the sensor circuit unit (50), a self-diagnosis application unit (51) in which a self-diagnosis output value to be output from the detection element (40) at the time of self-diagnosis of the detection element (40) is set as the first sensor output characteristic. When the request signal includes the self-diagnosis output value of the self-diagnosis application unit (51) as the second sensor output characteristic, the control unit (30) The diagnostic output value can be adjusted to the self-diagnosis output value as the second sensor output characteristic included in the request signal.

  According to this, when self-diagnosing whether the detection element (40) is functioning normally, the self-diagnosis output value which is the value of the self-diagnosis result can be adjusted. In this case, for example, the self-diagnosis output value can be adjusted by changing the resistance value of the resistor (51c).

  In the signal processing unit (55), a self-diagnosis output determination value for determining whether the self-diagnosis output value output from the detection element (40) is within a certain range as the first sensor output characteristic is set. When the request signal includes the self-diagnosis output determination value of the signal processing unit (55) as the second sensor output characteristic, the control unit (30) determines the self-diagnosis output determination value of the signal processing unit (55). Can be adjusted to the self-diagnosis output determination value as the second sensor output characteristic included in the request signal. Thus, the self-diagnosis output determination value for determining the self-diagnosis output value can be adjusted.

  When the rewritable memory (20) is provided, the memory (20) stores the ID code as the first sensor output characteristic, and the request signal includes the ID code as the second sensor output characteristic The control unit (30) can rewrite the ID code of the memory (20) with the ID code as the second sensor output characteristic included in the request signal.

  In this way, the ID code of the sensor device can be rewritten to another ID code. According to this, when performing control using a plurality of sensor devices, an ID code that can identify each sensor device can be assigned to each.

  In addition, a plurality of rewritable memories (20) are provided, and different sensor output characteristics are stored in each memory (20), and the control unit (30) is configured so that each sensor output characteristic stored in each memory (20) is stored. Can be adjusted to the sensor circuit section (50) in order.

  Thereby, a some sensor output characteristic can be set to a sensor circuit part (50) in order. For example, it is possible to switch the sensor output characteristics suitable for each scene according to the running state of the vehicle, such as when detecting a change in the speed of the vehicle on which the sensor device is mounted, a side slip control of the vehicle, or a vehicle collision. .

  A plurality of rewritable memories (20) are provided, and different sensor output characteristics are stored in each memory (20), and the control unit (30) is provided to the sensor circuit unit (50) in response to an external request. The set first sensor output characteristic can be adjusted to one of the sensor output characteristics stored in each memory (20).

  Thereby, the sensor output characteristic according to the situation where a sensor apparatus is mounted can be set to a sensor circuit part (50). In other words, the sensor device can be used in various situations.

  A plurality of rewritable memories (20) are provided, and the change history of adjustment of the first sensor output characteristic is stored in each memory (20), and the control unit (30) responds to an external request. Accordingly, the sensor output characteristics set in the sensor circuit unit (50) can be adjusted using the change history stored in each memory (20).

  This allows past sensor output characteristics to be set in the sensor circuit unit (50) using past sensor output characteristics data stored in the memory (20) without inputting a request signal to the sensor device from the outside. can do.

  Further, the detection signal processed by the sensor circuit unit (50) can be output as an analog signal to the outside, and the detection signal A / D converted by the A / D conversion unit (54) is output to the communication unit ( 10), the digital signal can be output to the outside.

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

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

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. In the present embodiment, for example, a sensor device that is mounted on a vehicle and used to operate an airbag will be described.

  FIG. 1 is a block diagram of a sensor device according to an embodiment of the present invention. As shown in this figure, the sensor device 1 includes a communication unit 10, a memory 20, a control unit 30, a detection element 40, and a sensor circuit unit 50. Among these, the sensor circuit unit 50 includes a self-diagnosis application unit 51, an amplifier circuit 52, a filter circuit 53, an A / D conversion unit 54, and a DSP unit 55.

  FIG. 2 shows circuit diagrams of the self-diagnosis application unit 51, the detection element 40, the amplifier circuit 52, and the filter circuit 53 in the sensor device 1 shown in FIG. Hereinafter, a description will be given with reference to FIGS. 1 and 2.

  The communication unit 10 is a communication unit that decodes a request signal input from the outside and inputs the content of the decoded request signal to the control unit 30. Such a communication unit 10 has a function of performing serial communication such as CAN. Note that the communication unit 10 may use DSI or PSI.

  This request signal includes the contents of the sensor output characteristics. The sensor output characteristic is a parameter when performing signal processing in the sensor device 1. Specifically, as the sensor output characteristics, the detection range (sensitivity) of the detection element 40, the response frequency range of the filter circuit 53, the output offset value set in the amplification circuit 52, and the offset value set in the amplification circuit 52 are constant. An output offset determination value for determining whether it is within the range, a self-diagnosis output value for setting a voltage value for performing self-diagnosis in the self-diagnosis application unit 51, and a self-diagnosis output value output from the sensor device 1 to the outside Indicates a self-diagnosis output determination value for determining whether or not is within a certain range, and an ID code parameter for identifying the sensor device 1. As described above, the request signal is a signal including a signal processing parameter in the sensor circuit unit 50.

  The request signal includes one or more of the adjustment values of each parameter as data. The adjustment value refers to an optimum value according to the vehicle type, location, and application to which the sensor device 1 is attached. That is, the communication unit 10 extracts the sensor output characteristics included in the request signal.

  Note that the sensor output characteristic included in the request signal corresponds to the second sensor output characteristic of the present invention. On the other hand, the sensor output characteristic set in the sensor device 1 at the stage where the sensor device 1 is manufactured corresponds to the first sensor output characteristic of the present invention.

  The memory 20 is a storage unit for storing data included in the request signal input to the communication unit 10, the initial adjustment value of the sensor output characteristic when the sensor device 1 is manufactured, and the like. As such a memory 20, for example, a rewritable nonvolatile memory is employed.

  Although only one memory 20 is illustrated in FIG. 1, a plurality of memories 20 may be provided. In this case, different data can be stored in each memory 20. For example, the ID code of the sensor device 1 that is the sensor output characteristic can be stored in one of the plurality of memories 20.

  The control unit 30 has a function of setting adjustment values of the self-diagnosis application unit 51, the detection element 40, the amplifier circuit 52, the filter circuit 53, and the like according to the content of the request signal input via the communication unit 10. is there. The operation of the control unit 30 will be described in detail later.

  The detection element 40 detects a physical quantity. In the present embodiment, since the sensor device 1 is used for an airbag, an acceleration sensor 41 that detects vehicle acceleration is employed as the detection element 40 as shown in FIG.

  Specifically, as the acceleration sensor 41, a beam structure having a comb-tooth structure that is generally known for a silicon substrate or the like is formed by detecting a change in capacitance. A structure in which a movable electrode and a fixed electrode are constituted by this beam structure is employed. As shown in FIG. 2, the first capacitor 41 a and the second capacitor 41 b in which the movable electrode and the fixed electrode are arranged to face each other are connected in series to constitute the acceleration sensor 41. Such an acceleration sensor 41 outputs a change in differential capacitance in each of the capacitors 41a and 41b.

  Further, as shown in FIG. 2, the detection element 40 is provided with a CV conversion unit 42. The CV conversion unit 42 converts an output of the acceleration sensor 41, that is, a change in differential capacitance into a voltage, and includes an operational amplifier 42a and a CV conversion capacitor 42b. The movable electrodes of the capacitors 41a and 41b of the acceleration sensor 41 are connected to the inverting input terminal of the operational amplifier 42a, and the CV conversion capacitor 42b is connected between the inverting input terminal and the output terminal of the operational amplifier 42a. .

  A self-diagnosis application unit 51 for outputting a reference voltage and performing self-diagnosis of the output of the acceleration sensor 41 is connected to a non-inverting input terminal of the CV conversion unit 42. The self-diagnosis application unit 51 is connected to the resistors 51a and 51b connected in series, the self-diagnosis adjustment resistor 51c connected to the connection point of each of the resistors 51a and 51b, and the self-diagnosis adjustment resistor 51c. The transistor 51d is turned on at the time of diagnosis.

  In such a configuration of the acceleration sensor 41, the CV conversion unit 42, and the self-diagnosis application unit 51, a reference voltage (for example, 2.5 V) that is a partial pressure of each of the resistors 51a and 51b of the self-diagnosis application unit 51 is detected when detecting acceleration. ) Is input to the non-inverting input terminal of the CV converter 42. Then, the inverting input terminal is biased to become the reference voltage by the operation of the operational amplifier 42a of the CV conversion unit 42, and the reference voltage of 2.5V is applied to each movable electrode of each capacitor 41a, 41b. Therefore, a potential difference between the reference voltages is always given to the capacitors 41a and 41b.

  Further, a rectangular wave voltage Vp having a phase difference of 180 ° and an amplitude of, for example, 5 V is periodically applied to the fixed electrodes of the capacitors 41 a and 41 b of the acceleration sensor 41. Thereby, when acceleration is applied to the acceleration sensor 41, each movable electrode of each capacitor 41a, 41b is displaced. Therefore, in the acceleration sensor 41, when the capacitance of the first capacitor 41a is C1 and the capacitance of the second capacitor C2 is C2, the differential capacitance change C1-C2 according to the displacement of the movable electrode of each capacitor 41a, 41b is obtained. Based acceleration is detected. A change C1-C2 in the differential capacitance according to the acceleration is output from the acceleration sensor 41 as a detection signal and input to the inverting input terminal of the CV conversion unit 42. In the CV conversion unit 42, when the capacitance of the CV conversion capacitor 42b of the CV conversion unit 42 is Cf, the detection signal is a voltage signal based on (C1-C2) × 5 V / Cf.

  On the other hand, during the self-diagnosis of the acceleration sensor 41, the transistor 51d is turned on by the control unit 30. As a result, the reference voltage (for example, 2.5 V) input to each movable electrode of each capacitor 41a, 41b is shifted by the resistance value of the self-diagnosis adjustment resistor 51c, so that the shifted reference voltage is restored. The differential capacitance change C1-C2 of each of the capacitors 41a and 41b is output from the acceleration sensor 41 as a self-diagnosis detection signal.

  The amplifier circuit 52 amplifies the voltage signal input from the detection element 40, and includes a resistor 52a, an operational amplifier 52b, a detection range adjustment resistor 52c, and an offset value adjustment resistor 52d. One end of the resistor 52a is connected to the output terminal of the operational amplifier 42a of the CV converter 42, and the other end is connected to the inverting input terminal of the operational amplifier 52b. Further, the detection range adjusting resistor 52c is connected between the inverting input terminal and the output terminal of the operational amplifier 52b, and the offset value adjusting resistor 52d is connected to the non-inverting input terminal of the operational amplifier 52b, so that the negative feedback amplifier circuit is provided. It is configured.

  In such an amplifier circuit 52, the detection range (sensitivity) of the acceleration sensor 41 is set by the resistance values of the resistor 52a and the variable detection range adjusting resistor 52c. Further, the offset value of the output of the acceleration sensor 41 is set by setting the reference voltage by the offset value adjusting resistor 52d.

  In the present embodiment, the detection range (sensitivity) of the acceleration sensor 41 is adjusted by changing the resistance value of the detection range adjustment resistor 52 c by the control unit 30, that is, by changing the amplification factor of the amplifier circuit 52. The offset value of the output of the acceleration sensor 41 is adjusted by changing the resistance value of the value adjusting resistor 52d.

  The filter circuit 53 allows only a desired frequency band component of the input voltage signal to pass therethrough, and includes a resistor 53a, an operational amplifier 53b, a frequency adjusting capacitor 53c, and a frequency adjusting resistor 53d. The output terminal of the operational amplifier 52b of the amplifier circuit 52 is connected to one end of the resistor 53a, and the other end is connected to the inverting input terminal of the operational amplifier 53b. In addition, a parallel circuit of the frequency adjusting capacitor 53c and the frequency adjusting resistor 53d is connected between the inverting input terminal and the output terminal of the operational amplifier 53b to constitute a negative feedback circuit. In the present embodiment, the filter circuit 53 functions as a low-pass filter. The output of the filter circuit 53 is output from the sensor device 1 as an analog output and also input to the A / D conversion unit 54.

  In such a filter circuit 53, the response frequency range of the acceleration sensor 41 is set by each value of the frequency adjusting capacitor 53c and the frequency adjusting resistor 53d. In addition, the response frequency range is adjusted by changing the values of the frequency adjusting capacitor 53c and the frequency adjusting resistor 53d by the control unit 30. By adjusting the response frequency range, for example, a cutoff frequency can be defined.

  The A / D converter 54 converts an analog voltage signal input from the filter circuit 53 into a digital signal.

  The DSP unit 55 performs signal processing on the digital voltage signal input from the A / D conversion unit 54. Such functions of the DSP unit 55 include processing such as digital filter and signal range separation. The output of the DSP unit 55 is output to the outside of the sensor device 1 as a digital output via the communication unit 10.

  In addition, the DSP unit 55 includes an output offset determination value and a self-diagnosis output determination value that indicate values within a certain range, and whether the voltage signal input from the filter circuit 53 is within the range of the output offset determination value, It is determined whether it is within the range of the self-diagnosis output determination value. When the voltage signal is not within the range of the output offset determination value or the self-diagnosis output determination value, the DSP unit 55 outputs a signal indicating abnormality. The DSP unit 55 corresponds to the signal processing unit (55) of the present invention.

  The above is the configuration of the sensor device 1 according to the present embodiment. The sensor device 1 may employ one in which each of the above-described constituent elements is constituted by a gate array, for example.

  Next, a method for adjusting the sensor output characteristics of the sensor device 1 will be described. Below, the case where the sensor output characteristic of the said sensor apparatus 1 is adjusted so that it may become the sensor output characteristic which the said sensor apparatus 1 should be provided when installing the sensor apparatus 1 in the desired place of a vehicle is demonstrated. In addition, the sensor device 1 is used for an airbag, and a plurality of sensor devices 1 are mounted on one vehicle.

  First, a plurality of sensor devices 1 shown in FIG. 1 are manufactured. In this case, the self-diagnosis adjustment resistor 51c of the self-diagnosis application unit 51, the detection range adjustment resistor 52c and the offset value adjustment resistor 52d of the amplifier circuit 52, the frequency adjustment capacitor 53c of the filter circuit 53, and the frequency adjustment resistor 53d. A plurality of sensor devices 1 are manufactured with each value as a predetermined value. That is, each sensor device 1 has the same sensor output characteristic. The initial adjustment value at the time of manufacturing the sensor device 1 may be stored in the memory 20.

  Next, each sensor device 1 is mounted in a predetermined place of the vehicle. There are various variations of the sensor device 1 for an air bag such as a front device, a side device, and a main device and a safing device. Each of these sensor devices 1 requires sensor output characteristics suitable for a vehicle type, a place installed in the vehicle, and the like, and the sensor output characteristics of each sensor device 1 are different. Therefore, the sensor output characteristics of each sensor device 1 are adjusted. Hereinafter, adjustment of sensor output characteristics of one sensor device 1 will be described.

  Specifically, an adjustment device for adjusting the sensor output characteristics of the sensor device 1 is used. FIG. 3 is a block diagram in which the adjusting device 2 is connected to the sensor device 1. The adjusting device 2 generates a request signal for adjusting the sensor output characteristics of the sensor device 1. As described above, the request signal includes the self-diagnosis adjustment resistor 51c of the self-diagnosis application unit 51, the detection range adjustment resistor 52c and the offset value adjustment resistor 52d of the amplifier circuit 52, and the frequency adjustment capacitor of the filter circuit 53. 53c, the frequency adjustment resistor 53d, the output offset determination value and the self-diagnosis output determination value of the DSP unit 55, and the ID code of the sensor device 1 or any one or more of them are included.

  Among these, the detection range (sensitivity) of the acceleration sensor 41 can be adjusted in two steps: “fine adjustment of the detection range” and “range switching of the detection range”. The fine adjustment of the detection range means that the acceleration currently applied to the acceleration sensor 41 is detected and adjusted to the target value included in the request signal. On the other hand, the range switching of the detection range is to switch the detection range (sensitivity) according to the request signal.

  The response frequency range can be adjusted in two steps: “fine adjustment of response frequency range” and “range switching of response frequency range”. The fine adjustment of the response frequency range is to detect the frequency of the acceleration currently applied to the acceleration sensor 41 and adjust the filter so that this frequency becomes a cut-off frequency (for example, −3 dB). On the other hand, the range switching of the response frequency range is to switch the response frequency according to the request signal.

  Then, a request signal including an adjustment command is input from the adjustment device 2 to the sensor device 1. As a result, the request signal is input to the communication unit 10 and decoded, and the decoded content is input to the control unit 30. Hereinafter, the operation of the control unit 30 will be described with reference to FIGS. 4 and 5. FIG. 4 is a flowchart showing the operation of the control unit 30. FIG. 5 is a diagram showing the exchange between the control device 30 and the host device such as the adjustment device 2.

  Here, “upper” is a device that establishes a connection relationship with the sensor device 1. In the case of adjusting the sensor output characteristics described below, the adjustment device 2 is higher than the sensor device 1. Further, when the sensor device 1 functions as a vehicle that detects the acceleration of the vehicle and outputs the value thereof, the higher rank of the sensor device 1 is an ECU that controls the airbag system.

  First, when the sensor device 1 is mounted on a vehicle as described above and power is supplied to the sensor device 1, the flow shown in FIG. 4 starts.

  That is, in step 100, the sensor device 1 performs a normal operation. In normal operation, when the sensor device 1 is manufactured, acceleration is detected by the sensor device 1 according to the initial value of the sensor output characteristic set in the sensor device 1, and a detection signal indicating the acceleration is output. The

  Specifically, in the normal operation mode shown in FIG. 5, a command for causing the sensor device 1 to perform normal operation is executed by the adjustment device 2, which is the host in the present embodiment. In the sensor device 1 that has received a normal operation command, the acceleration is detected by the detection element 40, signal processing is performed by the amplifier circuit 52, the filter circuit 53, the DSP unit 55, and the like, and the processing result is used as a response as an adjustment device. 2 is output. Thereby, in the adjustment apparatus 2, the determination with respect to the output of the sensor apparatus 1 and the output to another apparatus are performed.

  A numerical value such as “00” shown in FIG. 5 indicates a command in the upper adjustment device 2, and is set by the device.

  Then, in step 110, it is determined whether an adjustment command has been accepted. That is, it is determined whether or not the content of the request signal is input to the control unit 30. If it is not determined in this step that a request signal is not input, the process returns to step 100. Thereby, the sensor device 1 repeatedly performs the normal operation. On the other hand, if it is determined in this step that a request signal has been input, the process proceeds to step 120.

  Here, in this step 110, it is determined that the content of the request signal is input to the control unit 30. This means that in the adjustment mode shown in FIG. This is because an adjustment command for adjusting the sensor output characteristic, that is, a command is executed. In this case, the following adjustment items and target value data are output from the adjustment device 2 to the sensor device 1.

  In step 120, the adjustment item and the target value included in the request signal are accepted. The adjustment item is a part for adjusting a parameter among the constituent elements of the sensor device 1. For example, the self-diagnosis adjustment resistor 51c of the self-diagnosis application unit 51, the detection range adjustment resistor 52c of the amplifier circuit 52, the offset value adjustment resistor 52d, and the like correspond to adjustment items. The target value corresponds to the adjustment value of each adjustment item.

  “Adjustment items and target values are accepted” means that these adjustment items and target values included in the request signal are stored in the memory 20 by the control unit 30. In the case where the adjustment item and the target value are not stored in the memory 20, the process proceeds to step 130 after the adjustment item and the target value are received.

  Subsequently, in step 130, an adjustment status is output. That is, in the sensor device 1 that has received the request signal, a signal under adjustment indicating that the adjustment item and the target value in step 120 have been adjusted, that is, the detection signal output from the sensor device 1 is invalid is generated. The The in-adjustment signal is digitally output from the control unit 30 via the communication unit 10. Thereby, the malfunctioning of the adjusting device 2 is prevented.

  That is, in the adjustment mode shown in FIG. 5, the adjustment mode is switched in the sensor device 1, and the adjustment status output is performed in this step.

  Next, in step 140, adjustments are made. Adjustment means changing the adjustment item received in step 120 to a target value. That is, it refers to adjustment execution in the adjustment mode shown in FIG.

  Specifically, the control unit 30 controls the resistance value of the self-diagnosis adjustment resistor 51c of the self-diagnosis application unit 51, each resistance value of the detection range adjustment resistor 52c and the offset value adjustment resistor 52d of the amplifier circuit 52, and the filter circuit. One or more of the capacitance value of the frequency adjusting capacitor 53c, the resistance value of the frequency adjusting resistor 53d, the output offset determination value and the self-diagnosis output determination value of the DSP unit 55, and the ID code of the sensor device 1 are changed. . The ID code is changed when the data in the memory 20 is rewritten.

  In step 150, it is determined whether the adjustment has been completed normally. In this case, the output of the filter circuit 53 is input to the control unit 30 via the A / D conversion unit, the DSP unit 55, and the communication unit 10, and the output of the filter circuit 53 is within the normal value range in the control unit 30. Is determined. If it is determined that the adjustment has been completed normally, the process proceeds to step 160. If it is determined that the adjustment has not been completed normally, the process proceeds to step 170.

  In step 160, a completion notification is output. That is, as shown in the adjustment mode of FIG. 5, as a response of the sensor device 1, an adjustment result indicating that the adjustment is normally completed is output to the upper level. Also, the adjustment status output is canceled. That is, the output of the adjusting signal is stopped.

  Then, returning to step 100 again, a normal operation for detecting acceleration is performed. At the upper level, determination of the adjustment result output from the sensor device 1 and output to another device are performed.

  On the other hand, in step 170, an abnormality notification is output. That is, as shown in the adjustment mode of FIG. 5, as a response of the sensor device 1, an adjustment result indicating that the adjustment has not ended normally is output to the upper level. And the process of the control part 30 is complete | finished. In this case, the control unit 30 stops the operation of the sensor device 1 and returns to the sensor output characteristic before inputting the request signal. Thereafter, the sensor device 1 may perform a normal operation based on the sensor output characteristics that have been restored. In the upper level, determination of the adjustment result output from the sensor device 1 and output to another device are performed.

  Although the adjustment of the sensor output characteristics of one sensor apparatus 1 has been described above, the adjustment of each sensor apparatus 1 is performed so that the sensor output characteristics differ depending on the location where the sensor apparatus 1 is installed.

  The sensor output characteristics of each sensor device 1 may be adjusted after each sensor device 1 is mounted on the vehicle, or after each sensor device 1 is adjusted, each sensor device 1 is mounted on the vehicle. You may do it.

  After adjusting the sensor output characteristics of the sensor device 1 as described above, a self-diagnosis is performed to determine whether the acceleration sensor 41 outputs a correct value. Specifically, as shown in the self-diagnosis mode in FIG. 5, a self-check command for causing the sensor device 1 to perform a self-diagnosis is executed by the upper adjustment device 2. As a result, a command for performing a self-diagnosis is input from the adjustment device 2 to the sensor device 1.

  In the sensor device 1, the self-diagnosis mode is switched. That is, a self-diagnosis is performed in the sensor device 1, and a signal indicating that the acceleration value output from the sensor device 1 during the self-diagnosis is invalid is output from the sensor device 1.

  In this case, the control unit 30 turns on the transistor 51d of the self-diagnosis application unit 51 shown in FIG. Accordingly, the partial voltage of the resistors 51a and 51b in consideration of the resistance value of the self-diagnosis adjusting resistor 51c is input to the CV converter 42. Thus, since the shifted reference voltage is input to the acceleration sensor 41, a change in the differential capacitance that attempts to restore the shifted reference voltage is detected as a self-diagnosis output. A self-diagnosis output value based on the differential capacitance change is input to the DSP unit 55 as a self-diagnosis detection signal, and the DSP unit 55 determines whether the self-diagnosis output value is within a set range. Thereafter, the self-diagnosis result is output to the adjustment device 2, and the adjustment device 2 determines the result or outputs the result to another device.

  Such self-diagnosis is performed after the sensor device 1 is installed in the vehicle and the sensor output characteristics of the sensor device 1 are adjusted, or after the sensor device 1 is used for an airbag, It is executed when the vehicle ignition is turned on.

  As described above, when the sensor output characteristic suitable for each sensor device 1 is adjusted and the vehicle is operated by the user, the sensor device 1 functions as a component of the airbag system. In this case, the upper part of the sensor device 1 is an ECU that controls the airbag system.

  When the ignition of the vehicle is turned on, the sensor device 1 moves so as to detect the acceleration of the vehicle. At this time, as described above, the self-diagnosis function may be executed by the sensor device 1.

  Thereafter, normal operation of the sensor device 1 is executed by the control unit 30. That is, as shown in the normal operation mode of FIG. 5, signals are exchanged between the sensor device 1 and the host ECU. That is, normal operation is requested from the upper ECU to the sensor device 1, and the sensor device 1 repeats Step 100 and Step 110 shown in FIG. A digital signal and an analog signal are input.

  Thus, even when the normal operation is performed, the sensor output characteristics of the sensor device 1 may be adjusted. In this case, adjustment of the sensor output characteristic is included in advance in the command received by the sensor device 1 from the host. When the adjustment command is received by the sensor device 1, the target values of the detection range (sensitivity), offset value, response frequency, and self-diagnosis output are read from the data area following the command, and the sensor device 1 The self-adjustment is performed so that the output of is closest to the target value. At this time, a status signal indicating that the adjustment is in progress is output to the upper level, thereby preventing the higher level malfunction. When the adjustment is completed, the adjustment status signal is returned to the original state, and the sensor device 1 executes the normal operation output again.

  As described above, in the present embodiment, a request signal for adjusting sensor output characteristics is input from the outside to the sensor apparatus 1 having predetermined sensor output characteristics, and the location and usage of the sensor apparatus 1 are installed. The sensor device 1 is characterized by adjusting each of the sensor output characteristics that the sensor device 1 should have.

  According to this, even if a plurality of sensor devices 1 having common sensor output characteristics are manufactured, the sensor output characteristics can be changed according to the situation in which the sensor device 1 is used. For this reason, it is not necessary to manufacture what is provided with the sensor output characteristic suitable for the use of the sensor apparatus 1 conventionally, and it is not necessary to prepare the lineup of the sensor apparatus 1 according to each use. That is, it is possible to cope with all by one sensor device 1.

  In this way, even the sensor device 1 having only one type, that is, one type of sensor output characteristic, can cope with various vehicle types, uses, and mounting positions. It is not necessary to provide the output system in the sensor device 1. For this reason, the sensor device 1 can be manufactured at low cost without increasing the circuit scale, and the sensor device can be installed in a small space.

  Even if the sensor output characteristics of the sensor device 1 are adjusted, the sensor output characteristics can be adjusted at any time by newly inputting a request signal to the sensor device 1. Therefore, it is possible to finely adjust the sensor output characteristics and detect the acceleration according to the running state of the vehicle, the speed of the vehicle, the road surface condition, the behavior of the vehicle, the surrounding situation, and the like.

(Second Embodiment)
In the present embodiment, only different parts from the first embodiment will be described. In the present embodiment, an example of a command included in a request signal exchanged between the sensor device 1 and the sensor device 1 will be described. FIG. 6 is a diagram showing a list of commands handled by the sensor device 1 in the present embodiment.

  The command corresponds to a command from the host (adjustment device 2) to the sensor device 1.

  The command 00 indicates data of “setting No.”, and the setting No. Switch to the set value according to the output. For example, a plurality of memories 20 are provided in the sensor device 1, and different sensor output characteristics are set in each of the memories 20. The command is valid when it is stored together. In this case, the detection value of the set value is output from the sensor device 1 to the upper level.

  The command 01 indicates data of “detection range target value”, and causes the sensor device 1 to adjust the current detection value to the target value. Then, an adjustment status output indicating that adjustment is in progress is output from the sensor device 1, and when the adjustment is completed, the sensor device 1 makes either a normal end or a response indicating that adjustment is not possible.

  The command 02 indicates “detection range” data, calculates the ratio of the current detection range to the required detection range, and changes the amplification factor and the like. Then, the sensor device 1 makes a response indicating that the change has been completed or cannot be changed.

  The command 03 indicates data of “response frequency target value” and adjusts the current detection frequency to the target value. Then, an in-adjustment status output indicating that the response frequency target value is being adjusted by the sensor device 1 is made, and when the adjustment is completed, either a normal end or a response indicating that the adjustment cannot be made is made.

  The command 04 indicates data of “response frequency”, and calculates a ratio between the current response frequency and the request response frequency. Then, the sensor device 1 changes the filter constant or the like, and makes a response that the change is completed or cannot be changed.

  The command 05 points to the data of “offset target value” and adjusts to the requested offset value. Then, an adjustment status output indicating that the offset target value is being adjusted by the sensor device 1 is made, and when the adjustment is completed, either a normal end or a response indicating that the adjustment cannot be made is made.

  The command 06 points to data of “offset determination value” and is changed to the requested offset determination value. Then, the sensor device 1 changes the offset determination value and makes a response indicating that the change is completed or cannot be changed.

  The command 07 indicates data of “target value for self-diagnosis output” and adjusts it to the requested self-diagnosis output value. Then, an adjustment status output indicating that the self-diagnosis output target value is being adjusted is made by the sensor device 1, and either a normal end or a response indicating that adjustment is not possible is made when the adjustment is completed.

  The command 08 indicates data of “self-diagnosis determination value”, and is changed to the requested self-diagnosis determination value. Then, the sensor device 1 changes the self-diagnosis determination value, and makes a response indicating that the change is completed or cannot be changed.

  The sensor output characteristics of the sensor device 1 can be adjusted by executing the above commands at the host.

(Other embodiments)
In the first embodiment, the case where the acceleration sensor 41 is used as the detection element 40 has been described. However, in addition to the acceleration sensor 41, a pressure sensor, a magnetic field sensor, a gyro sensor, a solar radiation sensor, and the like having a signal processing circuit and a communication function. It can also be applied to other sensors.

  In the first embodiment, the detection range (sensitivity) and the offset value can be adjusted by one amplifier circuit 52, but this is an example. For example, a combination of an amplifier circuit 52 that can adjust only the detection range (sensitivity) and an amplifier circuit 52 that can adjust only the offset value may be used.

  In the first embodiment, the sensor circuit unit 50 includes the self-diagnosis application unit 51, the amplifier circuit 52, the filter circuit 53, the A / D conversion unit 54, and the DSP unit 55. However, this is merely an example. The sensor circuit unit 50 may not be provided with all of these. For example, the sensor circuit unit 50 may include only the amplifier circuit 52, or the sensor circuit unit 50 may include the amplifier circuit 52 and the filter circuit 53.

  In addition, although the sensor device 1 illustrated in FIG. 1 includes the memory 20, the sensor device 1 may not include the memory 20.

  Each circuit configuration of the acceleration sensor 41, the CV conversion unit 42, the self-diagnosis application unit 51, the amplifier circuit 52, and the filter circuit 53 shown in FIG. 2 is an example, and other circuit configurations may be used. . For example, the filter circuit 53 may have a circuit configuration in which a resistor and a capacitor are combined without using the operational amplifier 53b.

  In each of the above-described embodiments, the sensor output characteristics of the sensor device 1 are adjusted when the sensor device 1 is manufactured and the sensor device 1 is mounted on the vehicle. Instead, the sensor device 1 may be adjusted during shipment adjustment, when the vehicle is started, and during traveling.

  In each of the above embodiments, the output of the sensor device 1 is both a digital signal and an analog signal. However, only an analog signal according to an external request may be used, or only a digital signal via a communication function may be used.

  In each of the above-described embodiments, the case where the sensor device 1 is mounted on a vehicle has been described. However, the sensor device 1 may be attached not only to the vehicle but also to other devices. Moreover, what is necessary is just to make the number of the sensor apparatuses 1 which should be attached into the number according to the condition.

  For example, after the sensor device 1 is manufactured, before the sensor device 1 is shipped, the detection range (sensitivity), offset, response frequency, and self-diagnosis output can be adjusted according to customer requirements. Thereby, it is possible to respond to the detailed requests of customers. Further, in the process before the adjustment, the sensor device 1 can be manufactured in the same component and the same process, and the process can be simplified.

  On the other hand, the sensor output characteristics of each sensor device 1 can be adjusted when the sensor device 1 is assembled to an ECU or a vehicle. That is, since the sensor output characteristics of the sensor device 1 can be adjusted (customized) after being assembled to the vehicle, it is possible to prevent erroneous assembly and to deal finely according to the vehicle and application.

  Moreover, when adjusting each sensor apparatus 1 at the time of vehicle starting, the secular change of the sensor apparatus 1 can be correct | amended. Furthermore, by adjusting the sensor output characteristics of the sensor device 1 when the vehicle is running or stopped, output changes due to environmental changes can be corrected.

  And the error by the combination of a vehicle and ECU can also be correct | amended by adjusting the sensor output characteristic of the sensor apparatus 1 at the time of replacement | exchange of ECU which supervises the sensor apparatus 1. FIG.

  When switching a plurality of adjustment values or switching adjustment values in response to a request from a host, the number of sensor devices 1 required according to the application can be integrated into one. That is, one sensor device 1 can be used for various applications, and cost reduction, space saving, and power saving can be realized.

  Not only the adjustment method of the sensor output characteristic shown by said each embodiment but another adjustment method is also employable. Specifically, as a method of adjusting the detection range (sensitivity) of the acceleration sensor 41, in addition to the method of changing the amplification factor of the amplifier circuit 52, a method of changing the conversion range of the A / D conversion unit 54 or the DSP unit 55 It is possible to adopt a method of changing the output range.

  Further, as a method of adjusting the response frequency range of the acceleration sensor 41, in addition to the method of changing the filter constant of the filter circuit 53, the method of changing the sampling frequency of the A / D converter 54 and the digital filter of the DSP unit 55 are changed. The method to do can be adopted.

  As a method of adjusting the offset value of the output of the acceleration sensor 41, in addition to the method of changing the reference voltage of the amplifier circuit 52, the method of changing the reference voltage of the A / D conversion unit 54 or the reference value of the DSP unit 55 is changed. The method can be adopted.

  As a method of adjusting the output offset determination value of the acceleration sensor 41, in addition to the method of changing the threshold value of the DSP unit 55, a method of changing the reference voltage of the internal analog circuit or a method of changing the comparator threshold value of the amplifier circuit 52. Can be adopted.

  As a method of adjusting the self-diagnosis output value of the acceleration sensor 41, in addition to the method of changing the reference value of the DSP unit 55, the method of changing the self-excitation voltage of the internal analog circuit and the self-excitation application interval of the internal analog circuit are changed. A method of changing the output range, a method of changing the amplification factor of the internal analog circuit, a method of changing the conversion range of the A / D converter 54, and the like.

  As a method of adjusting the self-diagnosis output determination value of the acceleration sensor 41, in addition to the method of changing the reference value of the DSP unit 55, a method of changing the comparator threshold value of the internal analog circuit or a method of changing the threshold value of the DSP unit 55. Can be adopted.

  The adjustment method according to the acceleration sensor 41 as described above can also be adopted in other sensors.

  By providing the sensor device 1 with the memory 20 as in the above embodiments, the sensor output characteristics stored in the memory 20 can be adjusted any number of times. In addition, by providing the sensor device 1 with a plurality of memories 20, sensor output characteristics such as an initial adjustment value, an adjustment value at the time of mounting, a value at the time of starting the vehicle, and an adjustment value at the time of travel can be stored.

  In addition, the sensor device 1 is provided with an analog output and a digital output as the sensor detection signal output, and the above-described various adjustment functions are provided in both the analog circuit and the digital circuit, and the analog output and the digital output are output differently. It can also be.

  When the sensor device 1 includes a plurality of memories 20, each memory 20 has, for example, a sensor output characteristic corresponding to the speed of the vehicle, a sensor output characteristic for detecting a side slip of the vehicle, and a sensor output characteristic for detecting a vehicle collision. A plurality of sensor output characteristics such as these may be stored in advance, and the plurality of sensor output characteristics stored in each memory 20 may be switched in order.

  In addition, when the sensor device 1 includes a plurality of memories 20, it is possible to store different sensor output characteristics in each memory 20 and switch and adjust a plurality of setting values according to a request from the host. On the other hand, any one of the sensor output characteristics stored in each memory 20 can be used for adjustment.

  Further, when the sensor device 1 includes a plurality of memories 20, the adjustment change history is stored in each memory 20, and past setting values such as one previous and two previous values are stored in the sensor device 1 in response to a request from the host. It can also be set.

  Note that the steps shown in each figure correspond to means for realizing the function, and each step of the flowchart shown in FIG. 4 can be configured as hardware.

It is a block diagram of the sensor apparatus concerning one embodiment of the present invention. FIG. 2 is a circuit diagram of a self-diagnosis application unit, a detection element, an amplifier circuit, and a filter circuit in the sensor device shown in FIG. 1. It is the block diagram which connected the adjustment apparatus to the sensor apparatus. It is the flowchart which showed the action | operation of the control part. It is the figure which showed the exchange between higher ranks, such as a control part and an adjustment apparatus. In 2nd Embodiment, it is the figure which showed the list of the commands handled with a sensor apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Sensor apparatus, 10 ... Communication part, 20 ... Memory, 30 ... Control part, 40 ... Detection element, 50 ... Sensor circuit part, 51 ... Self-diagnosis application part, 51c ... Self-diagnosis adjustment resistor, 52 ... Amplifier circuit, 52b. Operational amplifier, 52c. Detection range adjustment resistor, 52d. Offset value adjustment resistor, 53 ... Filter circuit, 53c ... Frequency adjustment capacitor, 53d ... Frequency adjustment resistor, 54 ... A / D converter, 55 ... DSP Department.

Claims (13)

A detection element (40) for detecting a physical quantity and outputting a detection signal corresponding to the physical quantity;
A sensor circuit unit (50) for inputting the detection signal from the detection element (40) and processing the detection signal according to a first sensor output characteristic serving as a parameter for processing the detection signal;
A communication unit (10) for extracting a second sensor output characteristic included in a request signal input from the outside;
A control unit (30) for inputting the second sensor output characteristic from the communication unit (10) and adjusting the first sensor output characteristic of the sensor circuit unit (50) to the second sensor output characteristic; A sensor device comprising: The sensor circuit unit (50) includes an amplifier circuit (52) in which a detection range of the detection element (40) is set as the first sensor output characteristic.
When the detection signal includes the detection range in the amplification circuit (52) as the second sensor output characteristic, the control unit (30) includes the detection range in the amplification circuit (52) in the request signal. The sensor device according to claim 1, wherein the sensor device is adjusted to a detection range as the second sensor output characteristic. The sensor circuit unit (50) includes an amplifier circuit (52) in which an offset value of the detection signal is set as the first sensor output characteristic.
When the request signal includes the offset value in the amplifier circuit (52) as the second sensor output characteristic, the control unit (30) includes the offset value in the amplifier circuit (52) in the request signal. The sensor device according to claim 1, wherein the second sensor output characteristic is adjusted to an offset value. The sensor circuit unit (50) includes a filter circuit (53) in which a response frequency range that allows only a component of a desired frequency band to pass in the detection signal is set as the first sensor output characteristic,
When the request signal includes the response frequency range of the filter circuit (53) as the second sensor output characteristic, the control unit (30) sets the response frequency range of the filter circuit (53) to the request signal. 4. The sensor device according to claim 1, wherein the sensor device is adjusted to a response frequency range as the second sensor output characteristic included in the sensor. The sensor circuit unit (50) includes an A / D conversion unit (54) that performs A / D conversion of the detection signal, and an A / D conversion unit (54) that performs A / D conversion as the first sensor output characteristic. A signal processing unit (55) in which an output offset determination value for determining whether the D-converted detection signal is within a certain range is provided,
When the request signal includes the output offset determination value of the signal processing unit (55) as the second sensor output characteristic, the control unit (30) outputs the output offset determination value of the signal processing unit (55). 5. The sensor device according to claim 1, wherein the sensor device is adjusted to an output offset determination value as the second sensor output characteristic included in the request signal. 6. Self-diagnosis application in which a self-diagnosis output value to be output from the detection element (40) at the time of self-diagnosis of the detection element (40) is set as the first sensor output characteristic is applied to the sensor circuit unit (50). Part (51) is provided,
When the request signal includes the self-diagnosis output value of the self-diagnosis application unit (51) as the second sensor output characteristic, the control unit (30) performs self-diagnosis of the self-diagnosis application unit (51). 6. The sensor device according to claim 1, wherein an output value is adjusted to a self-diagnosis output value as the second sensor output characteristic included in the request signal. . The signal processing unit (55) includes a self-diagnosis output determination for determining whether the self-diagnosis output value output from the detection element (40) as the first sensor output characteristic is within a certain range. Value is set,
When the request signal includes the self-diagnosis output determination value of the signal processing unit (55) as the second sensor output characteristic, the control unit (30) outputs the self-diagnosis output of the signal processing unit (55). The sensor device according to claim 6, wherein the determination value is adjusted to a self-diagnosis output determination value as the second sensor output characteristic included in the request signal. It has a rewritable memory (20),
The memory (20) stores an ID code as the first sensor output characteristic,
When the request signal includes an ID code as the second sensor output characteristic, the control unit (30) uses the ID code of the memory (20) as the second sensor output characteristic included in the request signal. The sensor device according to claim 1, wherein the sensor device is rewritten to an ID code of A plurality of rewritable memories (20) are provided, and different sensor output characteristics are stored in each of the memories (20),
The said control part (30) adjusts each sensor output characteristic memorize | stored in each said memory (20) to the said sensor circuit part (50) in order, The 1st thru | or 8 characterized by the above-mentioned. The sensor device according to any one of the above. A plurality of rewritable memories (20) are provided, and different sensor output characteristics are stored in each of the memories (20),
In response to a request from the outside, the control unit (30) converts the first sensor output characteristic set in the sensor circuit unit (50) to any of the sensor output characteristics stored in the memories (20). The sensor device according to claim 1, wherein the sensor device is adjusted. A plurality of rewritable memories (20) are provided, and the change history of the adjustment of the first sensor output characteristic is stored in each memory (20),
The control unit (30) adjusts the sensor output characteristics set in the sensor circuit unit (50) using a change history stored in each memory (20) in response to an external request. The sensor device according to claim 1, wherein the sensor device is formed. 12. The sensor device according to claim 1, wherein the detection signal processed by the sensor circuit unit (50) is output to the outside as an analog signal. 6. The detection signal A / D converted by the A / D converter (54) is output to the outside as a digital signal via the communication unit (10). The sensor device according to any one of 12.

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