Load driving device and control method of load driving device

Abstract

The present invention provides a load driving device with high stability (linearity) and a control method thereof. In the load driving device in which multiple inductive loads are connected in parallel, even if a reverse current is temporarily detected in a specific inductive load, the load driving device can continue to operate normally without stopping.

Description

Technical Field

[0001] The present invention relates to the structure and control of a load driving device for driving and controlling an inductive load such as a solenoid valve, and more particularly to a technology that can be effectively applied to a vehicle-mounted load driving device requiring control stability (linearity). Background Art

[0002] Until now, automatic transmissions (transmission systems) for vehicles have used mechanisms that control multiple solenoid valves. In a typical transmission system, multiple inductive loads are connected to one controller (load driving device), and in order to reduce the number of connector terminals and achieve miniaturization, the vehicle side of the inductive loads uses common wiring.

[0003] As background technology in this technical field, there is a technology such as Patent Document 1. Patent Document 1 discloses a "wire harness connection method capable of reducing noise radiation of a solenoid valve control circuit and improving anti-interference performance", in which one end of the connection between a plurality of solenoid valves and their control devices is made a common wiring.

[0004] In addition, Patent Document 2 discloses a "driving device that achieves high-precision current control based on the voltage across the ends of a current-sensing resistor, and can detect a break in the common wiring by simultaneously detecting the direction of the current flowing through the resistor", wherein the current monitoring unit of each control driving unit monitors the current change in the common current path, and determines whether a break in the common wiring occurs based on the current change.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2016-97850

[0008] Patent Document 2: International Publication No. 2017 / 057682 Summary of the invention

[0009] Technical problem to be solved by the invention

[0010] When multiple inductive loads are connected to one load driving device as described above, and the vehicle side of the inductive loads (the side opposite to the side of the load connected to the load driving device) is connected by a common wiring, there is a concern about the impact of reverse current caused by current flowing from one inductive load to other inductive loads.

[0011] The conventional load driving device is configured to stop the operation of the load driving device when a reverse current is detected, and there is a possibility that the common wiring is judged to be abnormal even though the common wiring is in a normal state.

[0012] In a vehicle automatic transmission (transmission system), when the operation of a load driving device temporarily stops, a shift shock may be aggravated, that is, the stability (linearity) of control may be reduced, and the riding comfort (driving comfort) of the occupants may be deteriorated.

[0013] Therefore, an object of the present invention is to provide a load driving device with high stability (linearity) and a control method thereof, wherein, in a load driving device in which multiple inductive loads are connected in parallel, even if a reverse current is temporarily detected in a specific inductive load, normal operation can continue without stopping the load driving device.

[0014] Technical means of solving problems

[0015] To solve the above-mentioned problems, the present invention provides a load driving device, characterized in that it includes: a first switching element; a second switching element; a current and direction detection unit for detecting the forward and reverse currents flowing in the first switching element; a current and direction detection unit for detecting the forward and reverse currents flowing in the second switching element; a control unit, which calculates an average current based on signals from each of the current and direction detection units; a driving unit, which drives the first switching element and the second switching element based on the deviation between the average current and the target current; and a plurality of inductive loads, wherein one end of each of the plurality of inductive loads is connected to a common current path of the first switching element and the second switching element, and the wiring of each of the other ends is connected to the common wiring at one place, wherein even if the current and direction detection unit detects a reverse current when the second switching element is turned on, and the average current calculated by the control unit is in the opposite direction to that in normal times, current monitoring continues.

[0016] In addition, the present invention provides a control method for a load driving device that connects multiple inductive loads in parallel, characterized in that the current value and current direction of each of the multiple inductive loads are detected, and when the detected current direction is opposite to a specified current direction, the detected current value is compared with a specified threshold value, and when the detected current value is lower than the specified threshold value, the operation of the load driving device is continued.

[0017] Effects of the Invention

[0018] By adopting the present invention, in a load driving device that connects multiple inductive loads in parallel, even if a reverse current is temporarily detected in a specific inductive load, normal operation can continue without stopping the load driving device, thereby realizing a load driving device with high stability (linearity) and a control method thereof.

[0019] As a result, in a vehicle automatic transmission (transmission system) that controls the drive of a plurality of solenoid valves, it is possible to reduce the occurrence of a worsening shift shock, thereby improving the riding comfort (driving comfort) of the occupants.

[0020] Technical problems, technical features, and technical effects other than those described above can be made clear through the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a diagram showing a circuit configuration of a typical load driving device in a conventional vehicle automatic transmission (transmission system).

[0022] Figure 2 It is a diagram showing the circuit configuration of a load driving device according to the first embodiment of the present invention.

[0023] Figure 3 Yes means Figure 1 Timing diagram of the action (function) of the load driving device.

[0024] Figure 4 Yes means Figure 2 Timing diagram of the action (function) of the load driving device.

[0025] Figure 5 Yes means Figure 1 Flowchart of the operation flow of the common wiring abnormality diagnosis function in the load drive device.

[0026] Figure 6 Yes means Figure 2 Flowchart of the operation flow of the common wiring abnormality diagnosis function in the load drive device.

[0027] Figure 7 It is a diagram showing the circuit structure of a load driving device according to a second embodiment of the present invention. DETAILED DESCRIPTION

[0028] The following is an explanation of the embodiments of the present invention using the accompanying drawings. The same reference numerals are used to indicate the same structures in the drawings, and detailed explanation of the repeated parts is omitted.

[0029] Example 1

[0030] Reference Figure 1 to Figure 6 The structure of the load driving device and the control method thereof according to the first embodiment of the present invention are described.

[0031] In order to make the structure of this embodiment easy to understand, first, use Figure 1 , Figure 3 , Figure 5 A conventional load driving device will be described. Figure 1This is a circuit diagram of a conventional common load driving device provided as a comparative example.

[0032] like Figure 1 As shown, the conventional load driving device includes driver units Dr1 - 1 to Dr1 - 5 , a control unit 1 - 9 that controls each of the driver units Dr1 - 1 to Dr1 - 5 , and a connector terminal Co1 that can connect a plurality of inductive loads in parallel.

[0033] The driver unit Dr1-1 includes a first switching element 1-1, a second switching element 1-2, a first current detection switching element 1-3 connected in parallel with the first switching element 1-1, a second current detection switching element 1-4 connected in parallel with the second switching element 1-2, a current detection unit 1-5 of the first current detection switching element 1-3, a current detection unit 1-6 of the second current detection switching element 1-4, a first PWM driving unit 1-7 for driving the first switching element 1-1 and the first current detection switching element 1-3, a second PWM driving unit 1-8 for driving the second switching element 1-2 and the second current detection switching element 1-4, a current detection resistor 1-10 connected to a common current path of the first switching element 1-1 and the second switching element 1-2, and a current and direction detection unit 1-11 for detecting the current and its direction based on the voltage across the current detection resistor 1-10.

[0034] The control unit 1 - 9 calculates the average current based on the signals from the current detection unit 1 - 5 and the current detection unit 1 - 6 .

[0035] The driver units Dr1 - 2 to Dr1 - 5 have the same function as that of the driver unit Dr1 - 1 .

[0036] Driver units Dr1-1 to Dr1-5 are connected to connector terminal Co1. Driver units Dr1-1 to Dr1-5 are connected to connector terminals Co1-1 to Co1-5 which are one ends of inductive loads SL1-1 to SL1-5, respectively, and the other ends of inductive loads SL1-1 to SL1-5 are connected to common wiring 1-17 via wirings 1-12 to 1-16, respectively.

[0037] Figure 3 Yes means Figure 1 The timing diagram of the operation (action) of the conventional load driving device shown. Figure 3 A~D represent Figure 1 The action at A to D. Figure 3 Timing Figure 3-1 , 3-2, by making the first switch element 1-1 and the second switch element 1-2 alternately ON / OFF, as shown in the timing Figure 3-4 As shown, current flows out to the inductive load SL1-1.

[0038] At this time, the current is as follows Figure 3-3 When the current flows to the inductive load SL1-2, the current (reverse current) also flows to the inductive load SL1-1. Figure 3-4 As shown, the difference between the inflow current (reverse current) and the current flowing out from the driver unit Dr1-1 to the inductive load SL1-1 becomes the current of the inductive load SL1-1.

[0039] When the current in the inductive load SL1-1 flows in the opposite direction to the normal direction, the reverse current is detected by the current and direction detection unit 1-11, and it is determined that the common wiring 1-17 is disconnected. Figure 3-5 As shown, the disconnection flag is enabled by the control unit 1-9 (the flag changes from OFF to ON), so that the first switch element and the second switch element of the driver units Dr1-1 to Dr1-5 are both OFF (turned off), thereby stopping the operation of the driver units Dr1-1 to Dr1-5.

[0040] Figure 5 Yes means Figure 1 Flow chart of the operation flow of the abnormality diagnosis function of the common wiring 1-17 in the load driving device. In any one of the driver units Dr1-1 to Dr1-5, it is determined whether a reverse current flows when the second switch element is ON (conducting) (step 5-1), and when it is determined that the current detected by the current and direction detection unit 1-11 is in the normal direction ("No"), the disconnection flag is invalidated (flag OFF) (step 5-2), and the normal operation of the driver units Dr1-1 to Dr1-5 is continued.

[0041] On the other hand, if it is determined in step 5-1 that the current detected by the current and direction detection unit 1-11 is in the opposite direction to the normal direction (reverse current) ("Yes"), the disconnection flag is enabled (flag ON) (step 5-3), and the first switch element and the second switch element of each of the driver units Dr1-1 to Dr1-5 are OFF (turned off), thereby stopping the operation of all drivers (driver units Dr1-1 to Dr1-5) (step 5-4). As a result, the shift shock is aggravated, resulting in a significant reduction in driving comfort.

[0042] Next, use Figure 2 , Figure 4 , Figure 6 The load driving device of this embodiment will be described.

[0043] 《Structure of load driving device》

[0044] Figure 2 is a circuit diagram of the load driving device of this embodiment. Figure 2 As shown, the load driving device of this embodiment includes driver units Dr2-1 to Dr2-5, a control unit 2-9 that controls each of the driver units Dr2-1 to Dr2-5, and a connector terminal Co2 that can connect a plurality of inductive loads in parallel.

[0045] The driver unit Dr2-1 includes a first switching element 2-1, a second switching element 2-2, a first current detection switching element 2-3 connected in parallel with the first switching element 2-1, a second current detection switching element 2-4 connected in parallel with the second switching element 2-2, a current and direction detection unit 2-5 of the first current detection switching element 2-3, a current and direction detection unit 2-6 of the second current detection switching element 2-4, a first PWM driving unit 2-7 for driving the first switching element 2-1 and the first current detection switching element 2-3, and a second PWM driving unit 2-8 for driving the second switching element 2-2 and the second current detection switching element 2-4.

[0046] The control section 2 - 9 calculates the average current based on the signals from the current and direction detection section 2 - 5 and the current and direction detection section 2 - 6 .

[0047] Driver units Dr2 - 2 to Dr2 - 5 have the same function as that of driver unit Dr2 - 1 .

[0048] Driver units Dr2-1 to Dr2-5 are connected to connector terminal Co2. Driver units Dr2-1 to Dr2-5 are connected to connector terminals Co2-1 to Co2-5 which are one ends of inductive loads SL2-1 to SL2-5, respectively, and the other ends of inductive loads SL2-1 to SL2-5 are connected to common wiring 2-15 via wirings 2-10 to 2-14, respectively.

[0049] 《Feedback Control Based on Reverse Current》

[0050] Figure 4 Yes means Figure 2 The timing chart of the operation (action) of the load driving device of this embodiment is shown. Figure 4 A~D represent Figure 2 The action at A to D. Figure 4 Timing Figure 4-1 4-2, by turning on / off the first switch element 2-1 and the second switch element 2-2 alternately, as shown in the timing Figure 4-4 As shown, the current flows out to the inductive load SL2-1.

[0051] At this time, the current is as follows Figure 4-3 When the current flows to the inductive load SL2-2, the current (reverse current) also flows to the inductive load SL2-1. Figure 4-4 As shown, the difference between the inflow current (reverse current) and the current flowing out from the driver unit Dr2-1 to the inductive load SL2-1 becomes the current of the inductive load SL2-1.

[0052] Even when the current flows in the inductive load SL2-1 in the direction opposite to the normal direction, the control unit 2-9 can continue to monitor the average current and perform feedback control based on the deviation between the temporary transitional reverse current that changes over time and the target value, thereby maintaining the target current value with high accuracy even in the low indicated current range.

[0053] Thereby, even when the indicated current calculated by the control unit 2 - 9 is 0 A, it is possible to reliably maintain 0 A while continuing the feedback control.

[0054] 《Operation flow of the common wiring abnormality diagnosis function》

[0055] In the abnormality diagnosis function of the common wiring 2-15, when the average current calculated by the control unit 2-9 is in the opposite direction to the normal state and exceeds a predetermined abnormality determination threshold, it is determined that the common wiring 2-15 is abnormal (eg, disconnected).

[0056] Figure 6 The operation flow of the abnormality diagnosis function of this embodiment is shown. In any one of the driver units Dr2-1 to Dr2-5, it is determined whether a reverse current flows when the second switch element is ON (conducting) (step 6-1). If it is determined that the current detected by the current and direction detection unit 2-6 or the average current calculated by the control unit 2-9 is in the normal direction ("No"), the disconnection flag is invalid (flag OFF) (step 6-2), and the normal operation of the driver units Dr2-1 to Dr2-5 is continued.

[0057] On the other hand, when it is determined in step 6-1 that the current detected by the current and direction detection unit 2-6 or the average current calculated by the control unit 2-9 is in the opposite direction to the normal direction (reverse current) ("Yes"), it is determined whether the magnitude of the current in the reverse direction is greater than a specified value (prescribed threshold) (step 6-3).

[0058] When the magnitude of the reverse direction current is lower than a predetermined threshold value (No), the disconnection flag is invalidated (flag OFF) (step 6-2), and the normal operation of the driver units Dr2-1 to Dr2-5 is continued.

[0059] In addition, when the magnitude of the current in the reverse direction is greater than a specified value (prescribed threshold) ("Yes"), the disconnection flag is enabled (flag ON) (step 6-4), and the first switching element and the second switching element of each of the driver units Dr2-1 to Dr2-5 are both OFF (turned off), thereby stopping the operation of the driver units Dr2-1 to Dr2-5.

[0060] Therefore, if the reverse current is smaller than the abnormality determination threshold value, the normal state can be continued without stopping the operation of the load driving device, thereby reducing the occurrence of worsening shift shock.

[0061] 《Abnormality judgment threshold》

[0062] In setting the abnormality determination threshold, a value having a certain margin with respect to the magnitude of the current that can operate the inductive loads SL2 - 1 to SL2 - 5 or the magnitude of the current that can operate the inductive loads SL2 - 1 to SL2 - 5 is set.

[0063] The load driving device of this embodiment is characterized in that, compared with the prior art, the current and direction detection units 2-5 and 2-6 detect not only the magnitude of the current but also the direction of the current flow, and even if the direction of the average current calculated by the control unit 2-9 is opposite to the normal direction, the driver unit Dr2-1 does not stop driving the inductive load SL2-1, but continues to monitor the current. In addition, in this embodiment, the current value and current direction are detected for each of the plurality of switching elements constituting the load driving device.

[0064] Even if the average current flows in the reverse direction, feedback control can be performed based on the deviation between the average current calculated by the control unit 2 - 9 and the target value, and the target current value can be maintained with high accuracy even in the low indicated current range.

[0065] As described above, the load driving device of this embodiment includes: a first switch element 2-1; a second switch element 2-2; a current and direction detection unit 2-5, which detects the forward and reverse currents flowing in the first switch element 2-1; a current and direction detection unit 2-6, which detects the forward and reverse currents flowing in the second switch element 2-2; a control unit 2-9, which calculates the average current based on the signals from the current and direction detection units 2-5 and 2-6 respectively; a driving unit (driver unit Dr2-1), which calculates the average current based on the average current and the target current. Deviation, driving the first switch element 2-1 and the second switch element 2-2; multiple inductive loads SL2-1~SL2-5, each of which has one end connected to the common current path of the first switch element 2-1 and the second switch element 2-2, and the wiring of the other end of each is connected to the common wiring 2-15 at one place, wherein even when the current and direction detection unit 2-5 detects a reverse current when the second switch element 2-2 is turned on, and the average current calculated by the control unit 2-9 is in the opposite direction to that in normal times, the current continues to be monitored.

[0066] Furthermore, even when the average current calculated by the control unit 2 - 9 is in the opposite direction to that in the normal state, feedback control is continued to eliminate this situation so that the average current approaches the target current.

[0067] In addition, for the current detected by the current and direction detection unit 2-5, or the average current calculated by the control unit 2-9, there is an abnormality judgment threshold for judging the abnormality of the common wiring 2-15 in the current range in the opposite direction to the normal state. When the abnormality judgment threshold is exceeded, it is judged that the common wiring 2-15 has an abnormality, and based on the abnormality judgment processing of the control unit 2-9, one inductive load SL2-1, or multiple inductive loads SL2-1 to SL2-5 are controlled.

[0068] Furthermore, the abnormality determination threshold is set so that the threshold falls within a current range in the opposite direction to that in the normal state and has a magnitude of current that can operate the inductive loads SL2 - 1 to SL2 - 5 or less.

[0069] In addition, in this embodiment ( Figure 2 ), the common wiring 2-15 is a GND line connected to GND, and the second switching element 2-2 is a switching element connected to the low side.

[0070] By adopting the load driving device and the control method thereof of the present embodiment, in a load driving device in which multiple inductive loads are connected in parallel, even when a reverse current is temporarily detected in a specific inductive load, the load driving device can continue to operate normally without stopping the load driving device, thereby realizing a load driving device and the control method thereof with high stability (linearity).

[0071] As a result, in a vehicle automatic transmission (transmission system) that controls the drive of a plurality of solenoid valves, it is possible to reduce the occurrence of a worsening shift shock, thereby improving the riding comfort (driving comfort) of the occupants.

[0072] In addition, the detection performance of abnormality diagnosis on the common wiring 2 - 15 can be improved, and the reliability of the load driving device can be improved.

[0073] Example 2

[0074] Reference Figure 7 The structure of the load driving device and the control method thereof according to the second embodiment of the present invention are described. Figure 7 4 is a circuit diagram of the load driving device of this embodiment.

[0075] 《Structure of load driving device》

[0076] In Example 1 ( Figure 2 ), the common wiring 2-15 is the GND line, but this is based on the premise that the driving method of the inductive loads SL2-1 to SL2-5 adopts high-side driving. When the driving method of the inductive loads SL2-1 to SL2-5 adopts low-side driving, Figure 7 As shown, the common wiring 2-15 is a battery line.

[0077] 《Operation flow of the common wiring abnormality diagnosis function》

[0078] The reverse direction current flowing through the inductive loads SL2 - 1 to SL2 - 5 flows into the first switching element 2 - 1 , and the reverse direction current can be detected by the current and direction detection unit 2 - 5 .

[0079] Therefore, in this embodiment ( Figure 7 ) When the driving mode of the inductive load SL2-1 to SL2-5 adopts low-side driving, the operation flow is as follows: Figure 6 In step 6-1, a reverse current flows when the first switching element is turned on.

[0080] In this embodiment ( Figure 7 ), the common wiring 2-15 is a power supply (battery) line connected to the power supply VB, and the second switching element 2-2 is a switching element connected to the high side.

[0081] In addition, the present invention is not limited to the above-described embodiments, and may include various modifications.

[0082] For example, the above embodiments are described in detail to make the present invention easy to understand, but are not limited to having all the structures described. In addition, a part of the structure of a certain embodiment can be replaced with the structure of another embodiment, and the structure of another embodiment can be added to the structure of a certain embodiment. For a part of the structure of each embodiment, other structures can be added, deleted, or replaced.

[0083] Industrial Applicability

[0084] In each of the embodiments described above, a load driving device of an automatic transmission (transmission system) for a vehicle using a linear solenoid valve is used as an example, but the present invention can also be applied to an inkjet printer valve or a massage chair, etc., which uses multiple solenoid valves as pressure regulating valves or directional switching valves for oil or air.

[0085] Description of Reference Numerals

[0086] 1-1: First switch element

[0087] 1-2: Second switch element

[0088] 1-3: (First) Current detection switching element

[0089] 1-4: (Second) Current Detection Switching Element

[0090] 1-5: Current detection unit (of the first switching element)

[0091] 1-6: Current detection unit (of the second switching element)

[0092] 1-7: (First) PWM drive unit

[0093] 1-8: (Second) PWM drive unit

[0094] 1-9: Control Department

[0095] 1-10: Current detection resistor

[0096] 1-11: Current and direction detection unit

[0097] 1-12 to 1-16: The other end of the inductive load (wiring)

[0098] 1-17: Shared wiring

[0099] Co1: Connector terminal (for load drive device)

[0100] Co1-1 to Co1-5: One end of the inductive load (connector terminal)

[0101] Dr1-1~Dr1-5:Driver

[0102] SL1-1~SL1-5: Inductive load

[0103] 2-1: First switch element

[0104] 2-2: Second switch element

[0105] 2-3: (First) Current detection switching element

[0106] 2-4: (Second) Current Detection Switching Element

[0107] 2-5: Current and direction detection unit (of the first switching element)

[0108] 2-6: Current and direction detection unit (of the second switching element)

[0109] 2-7: (First) PWM drive unit

[0110] 2-8: (Second) PWM drive unit

[0111] 2-9: Control Department

[0112] 2-10 to 2-14: The other end of the inductive load (wiring)

[0113] 2-15: Shared wiring

[0114] Co2: Connector terminal (for load drive device)

[0115] Co2-1~Co2-5: One end of the inductive load (connector terminal)

[0116] Dr2-1~Dr2-5:Driver

[0117] SL2-1~SL2-5: Inductive load

[0118] 3-1 to 3-5: Timing diagram (for reverse current detection in the prior art)

[0119] 4-1 to 4-5: Timing diagram (when detecting reverse current in Example 1)

[0120] 5-1 to 5-4: Steps of (Flowchart of Reverse Current Detection in Conventional Technology)

[0121] 6-1 to 6-5: Steps of (Flowchart for Reverse Current Detection in Example 1)

Claims

1. A load driving device, characterized in that: include: a first switching element; a second switching element; a current and direction detection unit for detecting a forward current and a reverse current flowing in the first switching element; a current and direction detection unit for detecting a forward current and a reverse current flowing in the second switching element; a control unit that calculates an average current based on the signals from each of the current and direction detection units; a driving unit configured to drive the first switching element and the second switching element based on a deviation between the average current and a target current; and a plurality of inductive loads, wherein one end of each of the plurality of inductive loads is connected to a common current path of the first switching element and the second switching element, and the wiring of the other end of each of the plurality of inductive loads is connected to a common wiring at one point, Among them, even if the current and direction detection unit that detects the forward and reverse currents flowing in the second switching element when the second switching element is turned on detects a reverse current, and the average current calculated by the control unit is in the opposite direction to that in the normal state, the current monitoring is still continued and the driving of the driving unit is continued.

2. The load driving device according to claim 1, characterized in that: Even when the average current calculated by the control unit is in the opposite direction to that in the normal state, feedback control is continued to eliminate this situation and the average current is brought close to the target current.

3. The load driving device according to claim 1, wherein: With respect to the current detected by the current and direction detection unit for detecting the forward and reverse currents flowing in the second switching element, or the average current calculated by the control unit, there is an abnormality judgment threshold for judging the abnormality of the common wiring in the current range in the opposite direction to the normal state. When the abnormality judgment threshold is exceeded, it is judged that the common wiring has an abnormality, and based on the abnormality judgment processing of the control unit, one or more inductive loads are controlled.

4. The load driving device according to claim 3, characterized in that: In setting the abnormality determination threshold, the abnormality determination threshold is set to have a magnitude of current capable of operating the inductive load or lower than the magnitude in a current range in a direction opposite to that in a normal state.

5. The load driving device according to claim 1, wherein: The common wiring is a GND line.

6. The load driving device according to claim 5, characterized in that: The second switching element is a switching element connected to the low side.

7. The load driving device according to claim 1, wherein: The common wiring is a power supply line.

8. The load driving device according to claim 7, characterized in that: The second switching element is a switching element connected to the high side.

9. A control method for a load driving device in which a plurality of inductive loads are connected in parallel, characterized in that: detecting the current value and current direction of each of the plurality of inductive loads, When the detected current direction is opposite to the specified current direction, comparing the detected current value with a specified threshold value, When the detected current value is lower than the predetermined threshold value, the operation of the load driving device is continued.

10. The control method of the load driving device according to claim 9, characterized in that: When the detected current value is equal to or greater than the predetermined threshold value, the operation of the load driving device is stopped.

11. The control method of the load driving device according to claim 9, characterized in that: A current value and a current direction are detected for each of a plurality of switching elements constituting the load driving device.

12. The control method of the load driving device according to claim 9, wherein: The plurality of inductive loads are connected to a common wiring at a side opposite to the side connected to the load driving device. The common wiring is a GND line.

13. The control method of the load driving device according to claim 9, characterized in that: The plurality of inductive loads are connected to a common wiring at a side opposite to the side connected to the load driving device. The common wiring is a power supply line.

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