Sensor device

Abstract

When the start switch (26) is turned off, the sensor device (1) can supply power from the battery (99) and continue at least part of the operation. A sensor input processing unit (30, 300) has a sensor element (31), an input calculation processing circuit (32), and a storage unit (35). The input calculation processing circuit (32) calculates sensor information corresponding to a detection value of the sensor element (31). The storage unit (35) stores abnormality information including power failure information. The voltage holding circuits (51-54) are provided in a battery power supply line (Lb) that supplies the power of the battery (99) to the sensor input processing unit (30) without passing through the start switch (26), and can supply at least a voltage capable of holding the data of the storage unit (35) to the sensor input processing units (30, 300) when the temporary voltage of the battery (99) decreases.

Description

[0001] Cross-reference to related applications

[0002] This application is based on patent application No. 2022-117824 filed on July 25, 2022, and its contents are cited herein. Technical Field

[0003] The present invention relates to a sensor device. Background Art

[0004] Conventionally, there are known rotation angle detection devices for detecting the rotation angle of a motor, etc. For example, the rotation angle detection device of Patent Document 1 is applied to an electric power steering device and can continue at least a part of the operation using power from a battery while the ignition power is off.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2015-161584

[0008] In Patent Document 1, when the battery reaches the end of its life, for example, when the battery voltage drops due to a large current being supplied to the starter when starting the engine, the rotation angle detection device may not be able to continue operating. Summary of the invention

[0009] An object of the present invention is to provide a sensor device that can continue at least a part of its operation even when a battery voltage decreases.

[0010] The sensor device of the present invention can continue at least a part of its operation by supplying power from a battery while a start switch is off, and includes a sensor input processing unit and a voltage holding circuit.

[0011] The sensor input processing unit includes a sensor element, an input operation processing circuit, and a storage unit. The sensor element detects changes in physical quantities corresponding to the movement of the detection object, the input operation processing circuit calculates sensor information corresponding to the detection value of the sensor element, and the storage unit stores abnormal information including power failure information, which is related to a power failure in which power from a battery is no longer supplied when a start switch is disconnected.

[0012] The voltage holding circuit is provided on a battery power supply line that supplies the battery voltage to the sensor input processing unit without passing through the start switch, and when the battery voltage temporarily drops, the voltage holding circuit can supply at least a voltage capable of holding the data of the storage unit to the sensor input processing unit. Thus, even when the battery voltage drops, at least a part of the operation can be continued. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings.

[0014] Figure 1 This is a schematic configuration diagram of a steering system according to the first embodiment.

[0015] Figure 2 This is a block diagram for explaining the sensor device according to the first embodiment.

[0016] Figure 3 This is a circuit diagram showing a power storage circuit according to the first embodiment.

[0017] Figure 4 1 is a timing chart showing the voltage during cranking in a battery degradation condition according to a reference example.

[0018] Figure 5 This is a timing chart showing voltage during cranking in a battery deterioration state according to the first embodiment.

[0019] Figure 6 This is a flowchart for explaining the power consumption reduction process according to the first embodiment.

[0020] Figure 7 This is a flowchart for explaining the power consumption reduction process according to the second embodiment.

[0021] Figure 8 This is a flowchart for explaining the power consumption reduction process according to the third embodiment.

[0022] Fig. 9 1 is a circuit diagram showing a power storage circuit according to a fourth embodiment.

[0023] Fig.10 1 is a timing chart showing voltage during cranking in a battery deterioration state according to the fourth embodiment.

[0024] Fig.11 This is a block diagram illustrating a sensor device according to a fifth embodiment.

[0025] Fig.12 This is a block diagram illustrating a sensor device according to the sixth embodiment.

[0026] Fig.13 This is a block diagram illustrating a sensor device according to the sixth embodiment.

[0027] Fig.14 1 is a circuit diagram showing a booster circuit according to a sixth embodiment.

[0028] Fig.15 1 is a circuit diagram showing a booster circuit according to a sixth embodiment.

[0029] Fig.16 1 is a timing chart showing voltage during cranking in a battery deterioration state according to the sixth embodiment. DETAILED DESCRIPTION

[0030] Hereinafter, the sensor device of the present invention will be described based on the drawings. In the following, in a plurality of embodiments, substantially the same configurations are denoted by the same reference numerals and description thereof will be omitted.

[0031] (First Embodiment)

[0032] exist Figure 1 to Figure 5 A sensor device 1 of this embodiment is applied to an electric power steering device 8 . Figure 1 The structure of a steering system 90 including the electric power steering device 8 is shown. The steering system 90 includes a steering wheel 91 as a steering member, a steering shaft 92, a pinion 96, a rack shaft 97, wheels 98, the electric power steering device 8, and the like.

[0033] The steering wheel 91 is connected to the steering shaft 92. A torque sensor 94 for detecting the steering torque is provided on the steering shaft 92. A pinion 96 is provided at the top end of the steering shaft 92. The pinion 96 meshes with a rack shaft 97. A pair of wheels 98 are connected to both ends of the rack shaft 97 via a tie rod or the like.

[0034] When the driver rotates the steering wheel 91, the steering shaft 92 connected to the steering wheel 91 rotates. The rotational motion of the steering shaft 92 is converted into the linear motion of the rack shaft 97 through the pinion 96. The pair of wheels 98 are steered at an angle corresponding to the displacement of the rack shaft 97.

[0035] The electric power steering device 8 includes: a drive device 10 having an ECU 20 and a motor 80; and a reduction gear 89, etc., which is a power transmission part that reduces the rotation of the motor 80 and transmits it to the steering shaft 92. That is, the electric power steering device 8 of this embodiment is a so-called "steering column assist type", and the steering shaft 92 can be said to be a driven object. It can also be set to a so-called "rack assist type" that transmits the rotation of the motor 80 to the rack shaft 97.

[0036] The motor 80 outputs part or all of the torque required for steering, and the battery 99 (see Figure 2) is supplied with electric power and driven, so that the reduction gear 89 rotates forward and reversely. The drive device 10 is provided with an ECU 20 on one side of the axial direction of the motor 80, and is a so-called "mechatronic type", but it can also be a mechatronic split type in which the motor and the ECU are separately provided. By setting it as a mechatronic type, the ECU 20 and the motor 80 can be efficiently configured in a vehicle with limited mounting space. The sensor device 1 is provided in the ECU 20.

[0037] like Figure 2 As shown, power is supplied from the battery 99 to the ECU 20. The battery 99 is shared with other loads 79. In the present embodiment, the case where the load 79 is a starter motor is described. The ECU 20 is provided with a Bat terminal 21 and an IG terminal 25. Power is supplied directly from the battery 99 to the Bat terminal 21 without passing through a start switch 26 of the vehicle, such as an ignition switch. Power is supplied from the battery 99 to the IG terminal 25 via the start switch 26. Fuses 22 and 27 are provided in the power supply wiring of the Bat terminal 21 and the IG terminal 25, respectively. In the following, the start switch is appropriately set to "IG".

[0038] The sensor device 1 includes a sensor input processing unit 30, a control unit 40, and a power storage circuit 51. The sensor input processing unit 30 includes a sensor element 31, an input operation processing circuit 32, an abnormality diagnosis circuit 33, a power failure determination circuit 34, a memory circuit 35, a communication circuit 36, a voltage monitoring circuit 37, and a power consumption adjustment circuit 38.

[0039] The sensor device 1 is provided with a sensor Vs power supply terminal 301 connected to the Bat terminal 21 and a sensor Vcc power supply terminal 302 connected to the IG terminal 25. That is, the sensor device 1 of the present embodiment is configured so that power can be supplied from the battery 99 via the sensor Vs power supply terminal 301 even during the IG disconnection period, and at least a part of the operation including counting the number of rotations TC of the motor 80 can be continued.

[0040] Hereinafter, the voltage generated from the voltage supplied from the Bat terminal 21 and supplied to the sensor Vs power supply terminal 301 is referred to as the sensor power supply voltage Vs, and the voltage generated from the voltage supplied from the IG terminal 25 and supplied to the sensor Vcc power supply terminal 302 is referred to as the Vcc voltage. In addition, the wiring connecting the Bat terminal 21 and the sensor Vs power supply terminal 301 is referred to as the battery power supply line Lb, and the wiring connecting the IG terminal 25 and the sensor Vcc power supply terminal 302 is referred to as the IG power supply line Lig. A sensor stabilized power supply circuit 61 as a regulator or the like is provided on the battery power supply line Lb, and a control stabilized power supply circuit 62 is provided on the IG power supply line Lig.

[0041] The sensor element 31 is a magnetoresistive element such as an AMR sensor, a TMR sensor, or a GMR sensor, or a Hall element, and detects the magnetic field of a sensor magnet (not shown) that rotates integrally with the shaft of the motor 80, and outputs a detection signal to the input operation processing circuit 32. In the present embodiment, a plurality of sensor elements 31 are provided.

[0042] The input operation processing circuit 32 calculates the motor rotation angle θm and the number of rotations TC of the motor 80 based on the detection value of the sensor element 31. The elements used for calculating the motor rotation angle θm and the elements used for calculating the number of rotations TC can be separated, or the detection values ​​of at least some of the elements can be used in common for calculating the motor rotation angle θm and the number of rotations TC. The calculation result is stored in the memory circuit 35. The number of rotations TC can be calculated based on the count value by, for example, dividing one rotation of the motor 80 into three or more areas, and adding or subtracting the count according to the rotation direction each time the area changes. The number of rotations TC is used to calculate the absolute angle θa, which is the rotation amount from a reference position containing multiple rotation information. The absolute angle θa is a value that can be converted into a steering angle by a gear ratio, etc.

[0043] The abnormality diagnosis circuit 33 performs abnormality diagnosis of the input arithmetic processing circuit 32, etc. The abnormality diagnosis result is stored in the memory circuit 35. The power failure determination circuit 34 determines a power failure in which the power directly supplied from the battery 99 via the sensor Vs power supply terminal 301 is interrupted.

[0044] The memory circuit 35 stores information sent to the control unit 40, such as the motor rotation angle θm, the number of rotations TC, the abnormality diagnosis result, and information related to power failure. The storage area for storing each information is set to 2 bits or more to make it redundant, so that abnormality detection based on comparison and majority voting can be performed. In addition, a cyclic redundancy code (CRC), an error correction code (ECC), or an error detection code (EDC) can also be formed. As a result, reliability can be improved and it can be applied to products requiring high functional safety.

[0045] The communication circuit 36 ​​transmits the motor rotation angle θm, the number of rotations TC, the abnormality diagnosis result, and the information related to the power failure to the control unit 40. In addition, the communication circuit 36 ​​receives various information from the control unit 40. When the IG is turned on, the communication circuit 36 ​​transmits the number of rotations TC, the abnormality diagnosis result, and the power failure information when the IG is turned off to the control unit 40 according to the request signal from the control unit 40. In addition, when receiving the recovery signal from the control unit 40, the abnormality diagnosis result and the information related to the power failure in the memory circuit 35 are cleared. In the case where there are multiple storage areas for storing the abnormality diagnosis results and the power failure information, the determination results of the abnormality diagnosis circuit 33 and the determination results of the power failure determination circuit 34 can be stored in multiple areas of the memory at the same time and cleared at different times. For example, in the case where there are two storage areas, the following is the case: after the power failure information is sent according to the request signal sent from the control unit 40 when the IG is turned on, one is cleared according to the recovery signal sent when the control unit 40 receives the power failure information, and the other is cleared according to the recovery signal sent at an arbitrary time after the cranking is completed, such as the timing when the IG is turned off.

[0046] The voltage monitoring circuit 37 monitors the voltage of the battery power supply line Lb. In the present embodiment, the charging voltage Vcg between the power storage circuit 51 and the sensor stabilized power supply circuit 61 is monitored, but the sensor power supply voltage Vs or the Bat terminal voltage may be monitored instead of the charging voltage Vcg. The power consumption adjustment circuit 38 adjusts the power consumption in the sensor input processing unit 30 according to the charging voltage Vcg. The details will be described later.

[0047] The control unit 40 is mainly composed of a microcomputer, etc., and internally includes a CPU, ROM, RAM, I / O, and a bus connecting these structures, all of which are not shown. Each process in the control unit 40 may be a software process performed by the CPU executing a program pre-stored in a physical memory device such as a ROM (i.e., a readable non-temporary tangible storage medium), or a hardware process performed by a dedicated electronic circuit.

[0048] The control unit 40 performs various calculations related to the drive control of the motor 80. In addition, the control unit 40 uses the motor rotation angle θm and the number of rotations TC to calculate the absolute angle θa. In the present embodiment, at least one sensor element 31, the input calculation processing circuit 32, and the memory circuit 35 are always powered to continue the calculation of the number of rotations TC even when the IG is disconnected. Thus, even when the motor 80 rotates by steering the steering wheel 91 during the period when the IG is disconnected, the steering angle θs can be calculated without relearning the reference position. In addition, the motor rotation angle θm can use the value when the IG is turned on, so the calculation based on the constant power supply does not need to be continued.

[0049] Here, when the life of the battery 99 is approaching, when the battery voltage Vbat decreases due to the large current flowing in the starter when the engine is started, the sensor input processing unit 30 may not be able to operate. When the detection of the number of rotations TC is interrupted due to the voltage drop, the steering angle θs needs to be relearned, and the control of the side skid control system (ESC), automatic driving, etc. using the steering angle θs is delayed.

[0050] Therefore, in the present embodiment, the power storage circuit 51 is provided so that even when the voltage of the battery 99 decreases due to the driving of the load 79 having a large influence on the battery voltage Vbat, such as the starter motor, the operation guarantee voltage can be supplied to the sensor input processing unit 30 during the voltage holding period. Here, the voltage holding period is set according to the time required to recover from the voltage drop caused by the driving of the starter, for example.

[0051] like Figure 3 As shown, the power storage circuit 51 includes a capacitor 511 and a diode 512. The capacitor 511 is connected to the battery power supply line Lb and the ground line. The diode 512 is provided on the battery power supply line Lb so that the anode is on the Bat terminal 21 side and the cathode is on the capacitor 511 side.

[0052] Figure 4 and Figure 5 1 is a timing chart showing voltages during cranking in a battery deterioration state. The battery voltage Vbat is shown by a solid line, the charging voltage Vcg is shown by a dotted line, and the sensor power supply voltage Vs is shown by a dashed line. Fig.10 The same is true for etc. Figure 4 In the example of , when the charging voltage Vcg is sufficiently high, the sensor power supply voltage Vs is adjusted to a set value (e.g., 3.3 [V]) by the sensor stabilized power supply circuit 61. In addition, when the charging voltage Vcg is lower than the set value, the sensor power supply voltage Vs becomes a value corresponding to the charging voltage Vcg.

[0053] like Figure 4 As in the reference example shown in FIG. 1 , when the power storage circuit 51 is not provided, if the battery voltage Vbat decreases due to the cranking at time x90, the sensor power supply voltage Vs becomes lower than the minimum operating voltage (e.g., 3.0 [V]), and the sensor input processing unit 30 stops operating for a stop period X. In addition, when the capacity of the power storage circuit 51 is insufficient, the sensor input processing unit 30 may also fail to operate.

[0054] like Figure 5As shown, in the case where a power storage circuit 51 is provided, if a decrease in the battery voltage Vbat caused by cranking occurs at time x10, the power stored in the capacitor 511 is supplied to the sensor input processing unit 30 side. Therefore, the decrease in the charging voltage Vcg becomes gentle, and the sensor power supply voltage Vs can be maintained at a set value even during the cranking period. The decreasing speed of the charging voltage Vcg depends on the capacity of the capacitor 511. Therefore, the capacity of the capacitor 511 is set to a voltage that can maintain a degree of operation of the sensor input processing unit 30 during the period when the battery voltage Vbat decreases due to the cranking. Thus, even in the case of a decrease in the battery voltage due to the cranking, the operation of the sensor input processing unit 30 can continue. In addition, the battery voltage after the cranking is completed becomes higher than when the IG is turned on due to the power generation voltage of the AC generator not shown.

[0055] In addition, in this embodiment, the sensor input processing unit 30 is provided with a power consumption adjustment circuit 38. The power consumption adjustment circuit 38 suppresses power consumption by stopping power supply to each circuit block based on the charging voltage Vcg detected by the voltage monitoring circuit 37. Thus, the capacity required for the capacitor 511 can be suppressed.

[0056] based on Figure 6 The power consumption reduction process of this embodiment is described with reference to the flowchart of FIG. This process is executed by the power consumption adjustment circuit 38 at a predetermined cycle. Hereinafter, the "steps" such as step S101 are omitted and are simply represented by the symbol "S".

[0057] In S101, the power consumption adjustment circuit 38 determines whether the charging voltage Vcg is 3.0 [V] or more. When it is determined that the charging voltage Vcg is less than 3.0 [V] (S101: No), the process moves to S102, and the power failure determination and the writing circuit to the memory circuit 35 are stopped. In addition, since the minimum operation guarantee voltage of the memory circuit 35 is less than 3.0 [V] (for example, 2.0 [V]), although new writing to the memory circuit 35 is stopped, the information already written is retained. When it is determined that the charging voltage Vcg is 3.0 [V] or more (S101: Yes), the process moves to S103, and the power failure determination and the writing circuit to the memory circuit 35 are allowed to operate.

[0058] In S104, the power consumption adjustment circuit 38 determines whether the charging voltage Vcg is 4.3 [V] or more. If it is determined that the charging voltage Vcg is less than 4.3 [V] (S104: No), the process moves to S105 to stop the sensor element 31 and the input operation processing circuit. If it is determined that the charging voltage Vcg is 4.3 [V] or more (S104: Yes), the process moves to S106 to allow the sensor element 31 and the input operation processing circuit 32 to operate.

[0059] In S107, the power consumption adjustment circuit 38 determines whether the charging voltage Vcg is 5.5 [V] or more. If it is determined that the charging voltage Vcg is less than 5.5 [V] (S107: No), the process proceeds to S108 to stop the communication circuit 36. If it is determined that the charging voltage is 5.5 [V] or more (S107: Yes), the process proceeds to S109 to allow the operation of the communication circuit 36.

[0060] In S110, the power consumption adjustment circuit 38 determines whether the charging voltage Vcg is 8.0 [V] or more. If it is determined that the charging voltage Vcg is less than 8.0 [V] (S110: No), the process moves to S111 to stop the abnormality diagnosis circuit 33. If it is determined that the charging voltage Vcg is 8.0 [V] or more (S110: Yes), the process moves to S112 to allow the abnormality diagnosis circuit 33 to operate.

[0061] In this embodiment, the minimum operating voltage for each function to be operated is determined from the functional aspect, and the operation is stopped according to the charging voltage Vcg. Figure 6 The judgment thresholds of S101, S104, S107, and S110 correspond to the minimum operating voltage of each function. The judgment threshold shown here is an example and can be set arbitrarily. In addition, the priority will change due to the use of the application, so the order of stopping the function may also be different. The same is true for each judgment threshold in the power consumption suppression process involved in the embodiment described later.

[0062] As described above, the sensor device 1 of the present embodiment can continue at least a part of its operation by supplying power from the battery 99 while the start switch 26 is off, and includes the sensor input processing unit 30 and the power storage circuit 51 .

[0063] The sensor input processing unit 30 includes a sensor element 31, an input operation processing circuit 32, and a memory circuit 35. The sensor element 31 detects a change in a physical quantity corresponding to the operation of the motor 80. The input operation processing circuit 32 calculates the motor rotation angle θm and the number of rotations TC as sensor information corresponding to the detection values ​​of the sensor element 31. The memory circuit 35 stores abnormal information and sensor input operation processing results, the abnormal information including power failure information related to a power failure in which power is no longer supplied from the battery 99 when the start switch 26 is turned off.

[0064] The power storage circuit 51 is provided on the battery power supply line Lb that supplies the power of the battery 99 to the sensor input processing unit 30 without passing through the start switch 26, and when the voltage of the battery 99 temporarily decreases, a voltage capable of at least maintaining the data of the memory circuit 35 can be supplied to the sensor input processing unit 30. In detail, by providing the power storage circuit 51, even when the voltage of the battery 99 decreases, a voltage capable of maintaining the data of the memory circuit 35 is maintained during the voltage maintenance period set according to the crankshaft rotation period. Thus, even when the battery voltage Vbat temporarily decreases due to crankshaft rotation, etc., the sensor processing circuit results, abnormality diagnosis results, and power failure information in the IG disconnection can be maintained.

[0065] The power storage circuit 51 includes a capacitor 511 connected to the battery power supply line Lb. When the battery voltage Vbat decreases, the power stored in the capacitor 511 is used to appropriately maintain the sensor power supply voltage Vs.

[0066] The sensor input processing unit 30 includes a power consumption adjustment circuit 38, which, when the charging voltage Vcg, which is the voltage of the power storage circuit 51, decreases, stops the functions other than data retention in the memory circuit 35 in sequence according to the charging voltage Vcg. As a result, the time for which the sensor power supply voltage Vs is maintained at or above the operation guarantee voltage can be extended. In addition, the capacity of the power storage circuit 51 (specifically, the capacitor 511) can be reduced.

[0067] (Second Embodiment)

[0068] based on Figure 7 The second embodiment will be described. The second and third embodiments differ from the above-described embodiments in power consumption reduction processing, and thus the description will focus on this point.

[0069] based on Figure 7 The power consumption reduction process of this embodiment is described in the flowchart of FIG. Figure 6The processing of S101 to S105 in is the same. In S124, when it is determined that the charging voltage Vcg is 4.3 [V] or more (S124: Yes), the process proceeds to S126.

[0070] In S126, the power consumption adjustment circuit 38 determines whether the charging voltage Vcg is 5.5 [V] or more. If it is determined that the charging voltage Vcg is less than 5.5 [V] (S126: No), the process proceeds to S127, and if it is determined that the charging voltage Vcg is 5.5 [V] or more (S126: Yes), the process proceeds to S129.

[0071] In S127, which is transferred when the charging voltage Vcg is 4.3 [V] or more and less than 5.5 [V], the power consumption adjustment circuit 38 sets the sensor element 31 and the input operation processing circuit 32 to intermittent operation. The intermittent operation is designed to make the circuit that normally operates in 100 μs operate in 1 ms. In S128, which is transferred when the charging voltage Vcg is less than 5.5 [V], the power consumption adjustment circuit 38 stops the communication circuit 36.

[0072] In the case where it is determined that the charging voltage Vcg is 5.5 [V] or more (S126: Yes), the communication circuit 36 ​​is allowed to operate, and the sensor element 31 and the input operation processing circuit 32 are set to normal operation (operation at 100 μs in the above example). The processing of S130 to S132 is the same as Figure 6 The processing of S110 to S112 is the same.

[0073] In this embodiment, the sensor element 31 and the input operation processing circuit 32 are set to intermittent operation in a predetermined voltage range (in this embodiment, 4.3 [V] or more and less than 5.5 [V]) above the minimum operating voltage of the detection operation that stops the operation of the sensor element 31 and the input operation processing circuit 32 with relatively large power consumption. By reducing the operation frequency of the sensor element 31 and the input operation processing circuit 32, the power consumption when the battery voltage is reduced can be further suppressed. In addition, the same effect as the above-mentioned embodiment is achieved.

[0074] (Third Embodiment)

[0075] based on Figure 8 A third embodiment will be described. In this embodiment, the sensor power supply voltage Vs is monitored instead of the charging voltage Vcg to perform power consumption suppression processing. In this embodiment, since the sensor power supply voltage Vs is adjusted to 3.3 [V] or less, the minimum operating voltage is set within this range.

[0076] based on Figure 8The flowchart of the power consumption suppression process based on the sensor power supply voltage Vs is described. In S151, the power consumption adjustment circuit 38 determines whether the sensor power supply voltage Vs is 2.0 [V] or more. When it is determined that the sensor power supply voltage Vs is less than 2.0 [V] (S151: No), it transfers to S152. When it is determined that the sensor power supply voltage Vs is 2.0 [V] or more (S151: Yes), it transfers to S153. The processing of S152 and S153 is the same as Figure 6 The processing of S102 and S103 is the same.

[0077] In S154, the power consumption adjustment circuit 38 determines whether the sensor power supply voltage Vs is 2.5 [V] or more. If it is determined that the sensor power supply voltage Vs is less than 2.5 [V] (S154: No), the process moves to S155. If it is determined that the sensor power supply voltage Vs is 2.5 [V] or more (S154: Yes), the process moves to S156. The processing of S155 and S156 is the same as Figure 6 The processing of S105 and S106 is the same.

[0078] In S157, the power consumption adjustment circuit 38 determines whether the sensor power supply voltage Vs is 3.0 [V] or more. If it is determined that the sensor power supply voltage Vs is less than 3.0 [V] (S157: No), the process moves to S158 to stop the communication circuit 36 ​​and the abnormality diagnosis circuit 33. If it is determined that the sensor power supply voltage Vs is 3.0 [V] or more (S157: Yes), the process moves to S159 to allow the communication circuit 36 ​​and the abnormality diagnosis circuit 33 to operate.

[0079] In this embodiment, the sensor power supply voltage Vs is monitored instead of the charging voltage Vcg, and the power consumption adjustment circuit 38 sequentially stops the functions other than data retention in the memory circuit 35 according to the sensor power supply voltage Vs. Even with such a configuration, the same effects as the above embodiment are achieved.

[0080] (Fourth Embodiment)

[0081] exist Fig. 9 and Fig.10 A fourth embodiment is shown. In this embodiment, the power storage circuit is different from the above-mentioned embodiment, so the description will focus on this point. Fig. 9 As shown, the power storage circuit 52 of this embodiment includes a secondary battery 521, a charging control circuit 522, and diodes 523 and 524. The charging control circuit 522 is provided to prevent overcharging of the secondary battery 521, and may be, for example, a resistor.

[0082] The diodes 523 and 524 are both provided with the anode on the battery side and the cathode on the sensor power supply side. The diode 523 is provided between the Bat terminal 21 and the secondary battery 521, and the diode 524 is provided between the secondary battery 521 and the sensor stabilized power supply circuit 61.

[0083] When the battery voltage Vbat is sufficiently high, power is supplied to the sensor input processing unit 30 via the wiring La connecting the cathodes of the diodes 523 and 524. On the other hand, when the battery voltage Vbat decreases, power from the secondary battery 521 is supplied to the sensor input processing unit 30 via the diode 524.

[0084] like Fig.10 As shown, when the battery voltage Vbat decreases due to the crankshaft rotation at time x20, the power stored in the secondary battery 521 is supplied to the sensor input processing unit 30. The capacity of the secondary battery 521 is also set to a voltage that can maintain the sensor input processing unit 30 during the period when the battery voltage Vbat decreases due to the crankshaft rotation, similarly to the capacitor 511. Fig.10 In the example of , the charging voltage Vcg is maintained at the voltage of the secondary battery 521 until time x21, and then gradually decreases. The sensor power supply voltage Vs is maintained at a set value by the power from the secondary battery 521 during the cranking period.

[0085] In this embodiment, the power storage circuit 52 includes a secondary battery 521 connected to the battery power supply line Lb. Thus, when the battery voltage Vbat decreases, the sensor power supply voltage Vs can be appropriately maintained by using the power of the secondary battery 521. In addition, the same effects as the above embodiment are achieved.

[0086] (Fifth Embodiment)

[0087] exist Fig.11 A fifth embodiment is shown. The sensor input processing unit 300 of this embodiment is different from the above-mentioned embodiment in that the voltage monitoring circuit 37 is omitted. Figure 6 In the embodiment, the power storage circuit 51 of the first embodiment is considered to be provided, but it may be provided as the power storage circuit 52 of the fourth embodiment. In the present embodiment, the charging voltage Vcg is monitored by the control unit 40. In addition, Figure 6 The calculations related to the power consumption reduction process shown are executed by the control unit 40, and the power consumption adjustment circuit 38 is operated according to the instruction from the control unit 40. This simplifies the structure of the sensor input processing unit 300. In addition, the same effects as those of the above embodiment are achieved.

[0088] (Sixth Embodiment)

[0089] exist Figure 12 to Figure 16 A sixth embodiment is shown. Fig.12 and Fig.13 As shown in FIG. 2 , the sensor device 2 is different from the above-described embodiment in that a boost circuit 53 is provided instead of a power storage circuit. Fig.12 As shown in FIG. 1 , the voltage monitoring circuit 37 for monitoring the boost voltage Vbu may be provided on the sensor input processing unit 30 side, or as shown in FIG. Fig.13 As shown, the boost voltage Vbu is monitored by the control unit 40 .

[0090] like Fig.14 The boost circuit 53 includes a switch element 531, an inductor 532, a diode 533, a capacitor 534, and a boost control circuit 535, and can apply a boost voltage Vbu to the sensor input processing unit 30 by controlling the on and off operation of the switch element 531.

[0091] In addition, the boost circuit 53 may be replaced by Fig.15 The boost circuit 54 has a charge pump structure as shown. The boost circuit 54 has a switch circuit unit 541 to 543 composed of two switches and a capacitor, a diode 544, a capacitor 545, and a boost control circuit 546. By switching the on and off states of the switch circuit units 541 and 543, a boost voltage Vbu can be applied to the sensor input processing unit 30. Fig.15 In FIG. 1 , an example in which three switch circuit portions 541 to 543 are provided is shown, but the number of switch circuit portions may be any number.

[0092] When the voltage of the battery 99 is reduced by driving a load 79 such as a motor that consumes a large amount of power, such as a starter, the battery voltage Vbat does not actually drop to 0 [V], but a voltage of about 2 [V] remains. Therefore, in this embodiment, the remaining power of the battery 99 is fully utilized by providing the boost circuits 53 and 54. Here, the form of the boost circuit may be a form other than the form represented by the boost circuits 53 and 54.

[0093] like Fig.16 As shown, even if the battery voltage Vbat decreases to about 2 [V] due to the cranking at time x30, the sensor power supply voltage Vs can be maintained at the set value by driving the boost circuits 53 and 54. Thus, the operation of the sensor input processing unit 30 can be continued.

[0094] In this embodiment, booster circuits 53 and 54 are provided as voltage holding circuits in the battery power supply line Lb. Thus, even when the battery voltage Vbat decreases, the sensor power supply voltage Vs can be appropriately held. In addition, the same effects as those of the above embodiment are achieved.

[0095] In the embodiment, the memory circuit 35 corresponds to the "storage unit", the power storage circuits 51, 52 and the boost circuits 53, 54 correspond to the "voltage holding circuit", and the motor 80 corresponds to the "detection object". In addition, the motor rotation angle θm and the number of rotations TC of the motor 80 correspond to the "sensor information".

[0096] (Other embodiments)

[0097] In the above-mentioned embodiment, the stabilized power supply circuit for the sensor is provided outside the sensor input processing device. In other embodiments, the stabilized power supply circuit for the sensor may also be provided inside the sensor input processing device. The boost circuit of the fourth embodiment is also the same. In addition, in the sensor input processing device, miniaturization can be achieved by integrating the parts other than the inductor and capacitor which are difficult to be integrated into an IC and performing single packaging.

[0098] In the above-mentioned embodiment, the charging voltage or the boost voltage is monitored by the voltage monitoring circuit or the control unit, and the power consumption adjustment circuit performs the power consumption suppression process corresponding to the voltage. In other embodiments, especially when a boost circuit is provided, the power consumption adjustment circuit may be omitted, and the power consumption suppression process corresponding to the voltage may not be performed.

[0099] In the above embodiment, the sensor device detects the rotation of the motor. In other embodiments, the sensor device may also be a sensor device other than the motor rotation angle sensor, such as a torque sensor, a steering sensor, etc. In the above embodiment, one control unit is provided for one sensor input processing circuit. In other embodiments, multiple control units may be provided for one sensor input processing circuit, or multiple sensor input processing circuits may be provided for one control unit.

[0100] In the above embodiment, the motor is a three-phase brushless motor. In other embodiments, the motor unit is not limited to a three-phase brushless motor, but may be any motor. In addition, the motor unit is not limited to a motor (electric motor), but may be a generator or a so-called electric generator having the functions of both an electric motor and a generator. In the above embodiment, the sensor device is applied to an electric power steering device. In other embodiments, the sensor device may also be applied to devices other than the electric power steering device.

[0101] The control unit and method described in the present invention can be implemented by a special-purpose computer, which is provided by a processor and a memory programmed to execute one or more functions embodied by a computer program. Alternatively, the control unit and method described in the present invention can also be implemented by the following special-purpose computer, which is provided by a processor composed of one or more special-purpose hardware logic circuits. Alternatively, the control unit and method described in the present invention can also be implemented by one or more special-purpose computers, which are composed of a combination of a processor and a memory programmed to execute one or more functions and a processor composed of one or more hardware logic circuits. In addition, the computer program can be stored as an instruction executed by a computer in a non-transient tangible recording medium that can be read by a computer. As described above, the present invention is not subject to any limitation of the above-mentioned embodiments and can be implemented in various ways without departing from its main purpose.

[0102] The present invention is described based on the embodiments. However, the present invention is not limited to the embodiments and structures. The present invention also includes various modifications and variations within the equivalent range. In addition, various combinations and modes, and even other combinations and modes that only include one element, more than one element, or less than one element in them, are also included in the scope and thought range of the present invention.

Claims

1. A sensor device capable of continuing at least a part of its operation by supplying power from a battery (99) while a start switch (26) is turned off, characterized in that: have: A sensor input processing unit (30, 300) comprising a sensor element (31) for detecting a change in a physical quantity corresponding to an action of a detection object (80), an input operation processing circuit (32) for calculating sensor information corresponding to a detection value of the sensor element, and a storage unit (35) for storing abnormal information including power failure information related to a power failure in which power is no longer supplied from the battery when the start switch is disconnected; as well as A voltage holding circuit (51-54) is provided on a battery power supply line for supplying the power of the battery to the sensor input processing unit without passing through the start switch, and when the voltage of the battery temporarily decreases, the voltage holding circuit can at least supply a voltage capable of maintaining the data of the storage unit to the sensor input processing unit.

2. The sensor device according to claim 1, characterized in that The voltage holding circuit (51) has a capacitor (511) connected to the battery power supply line.

3. The sensor device according to claim 1, characterized in that The voltage holding circuit (52) has a secondary battery (521) connected to the battery power supply line.

4. The sensor device according to claim 1, characterized in that The voltage holding circuit (53, 54) is a boost circuit provided in the battery power supply line.

5. The sensor device according to any one of claims 1 to 4, characterized in that: The sensor input processing unit includes a power consumption adjustment circuit (38) which sequentially stops functions other than data retention in the storage unit according to the voltage of the voltage holding circuit when the voltage of the voltage holding circuit decreases.

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