Controls

Abstract

A control device for a vehicle includes a semiconductor switch, and controls the on and off of the semiconductor switch to open and close between a capacitor connected to one end of the semiconductor switch and a vehicle-mounted battery connected to the other end of the semiconductor switch. The control device includes: wiring for applying a driving voltage to the semiconductor switch to turn on the semiconductor switch; a driving switch for short-circuiting the wiring to turn off the semiconductor switch; a Zener diode with an anode connected to one end and a cathode connected to the wiring; a voltage detection unit to detect the voltage at one end; and a control unit to determine whether the semiconductor switch is faulty by controlling the driving switch from off to on and comparing the detected voltage with a threshold value.

Description

Technical Field

[0001] The present disclosure relates to a control device.

[0002] This application claims the benefit of priority based on Japanese Application No. 2019-085996, filed on April 26, 2019, and incorporates all the contents described in the aforementioned Japanese Application by reference. Background Art

[0003] Patent document 1 discloses a vehicle control device in which a fault diagnosis unit is provided in a semiconductor switch in a switch circuit including the semiconductor switch for controlling a large current supplied to a load. The fault diagnosis unit diagnoses whether the semiconductor switch has malfunction by determining the matching between an on / off control signal input to the semiconductor switch and an output level of the semiconductor switch.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2005-39385 Summary of the invention

[0007] Problems to be solved by the invention

[0008] The present method relates to a control device, which is a control device for a vehicle that has a switch circuit and controls the on-off of the switch circuit to open and close between a vehicle-mounted device and a vehicle-mounted battery, wherein the switch circuit has a semiconductor switch, the vehicle-mounted device has a capacitor connected to one end of the switch circuit, and the vehicle-mounted battery is connected to the other end of the switch circuit, and the control device has: wiring for applying a driving voltage to the gate of the semiconductor switch to turn on the semiconductor switch; a driving switch for short-circuiting the wiring to turn off the semiconductor switch; a voltage-stabilizing diode having an anode connected to the one end and a cathode connected to the wiring; a voltage detection unit that detects the voltage at the one end; and a control unit that determines whether the switch circuit has a fault by controlling the driving switch from off to on and comparing the voltage detected by the voltage detection unit with a predetermined threshold value.

[0009] In addition, the present application can be implemented not only as a control unit having such a characteristic processing unit, as described above, but also as a control method with the above characteristic processing as steps, or as a program for causing a computer to execute the above steps. In addition, it can be implemented as a semiconductor integrated circuit that implements part or all of the control device, or as other systems including the control device. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1This is a circuit block diagram for explaining a configuration example of a vehicle current control system according to the first embodiment.

[0011] Figure 2 This is a block diagram showing a configuration example of a control device according to the first embodiment.

[0012] Figure 3 It is an explanatory diagram showing a failure determination method.

[0013] Figure 4 It is an explanatory diagram showing a failure determination method.

[0014] Figure 5 is a timing chart showing a method for diagnosing a short-circuit fault.

[0015] Figure 6 : is a block diagram showing a configuration example of a control device according to a comparative example.

[0016] Fig. 7A This is a timing chart showing the effect of the control device according to the first embodiment.

[0017] Figure 7B This is a timing chart showing the effect of the control device according to the first embodiment.

[0018] Figure 8 This is a block diagram showing a configuration example of a control device according to the second embodiment.

[0019] Fig. 9 This is a block diagram showing a configuration example of a control device according to the third embodiment. DETAILED DESCRIPTION

[0020] [Problems to be Solved by the Present Disclosure]

[0021] In the vehicle control device involved in Patent Document 1, when a capacitor is connected to the circuit of the vehicle-mounted device that is the switching control target, if the capacitance of the capacitor is large, there is a technical problem that it takes time to discharge the capacitor and it takes time to diagnose a fault in the switching circuit.

[0022] For example, in a configuration where a switch circuit is used to open and close the connection between a starter having a capacitor and a vehicle battery, even if the switch circuit is turned on, it takes time for the capacitor to discharge and the voltage to drop. As a result, it takes time to diagnose whether the switch circuit is operating normally.

[0023] An object of the present disclosure is to provide a control device that can efficiently discharge a capacitor when a capacitor of an onboard device that is a switching control target is connected, and can determine whether a switching circuit has a fault in a short time.

[0024] [Effects of the present disclosure]

[0025] According to the present disclosure, it is possible to provide a control device that can efficiently discharge a capacitor when a capacitor of an onboard device that is a switching control target is connected, and can determine whether a switching circuit has a fault in a short time.

[0026] [Description of Embodiments of the Present Disclosure]

[0027] First, the embodiments of the present disclosure will be described by way of examples. In addition, at least a part of the embodiments described below may be arbitrarily combined.

[0028] (1) The present method relates to a control device, which is a control device for a vehicle that has a switch circuit and controls the on-off of the switch circuit to open and close the connection between an on-board device and an on-board battery, wherein the switch circuit has a semiconductor switch, the on-board device has a capacitor connected to one end of the switch circuit, and the on-board battery is connected to the other end of the switch circuit, and the control device has: wiring for applying a driving voltage to the gate of the semiconductor switch to turn on the semiconductor switch; a driving switch for short-circuiting the wiring to turn off the semiconductor switch; a Zener diode having an anode connected to the one end and a cathode connected to the wiring; a voltage detection unit that detects the voltage at the one end; and a control unit that determines whether the switch circuit has a fault by controlling the driving switch from off to on and comparing the voltage detected by the voltage detection unit with a predetermined threshold value.

[0029] According to this aspect, the control unit can determine whether or not there is a failure in the switching circuit in a time shorter than the time required to completely discharge the capacitor charged by the vehicle-mounted battery.

[0030] When determining whether the switch circuit has a fault, the control unit controls the drive switch from off to on. When the drive switch is off, the semiconductor switch is turned on (refer to Figure 3 When the drive switch is turned on, the semiconductor switch is turned off (refer to Figure 4 ). When the switch circuit is turned on, the capacitor is connected to the vehicle battery and the capacitor is charged. Through the control of the above-mentioned drive switch, when the switch circuit is normally turned off, the capacitor is disconnected from the vehicle battery and the capacitor begins to discharge (refer to Figure 4 ).

[0031] When the capacitor is discharged and the voltage at one end of the switch circuit is reduced to the reference potential, it can be determined that the switch circuit is normally controlled from on to off.

[0032] In particular, according to this method, the charge accumulated in the capacitor is discharged through the voltage stabilizing diode, wiring and driving switch. Therefore, compared with the case where the capacitor is discharged naturally, the capacitor can be discharged in a shorter time. Therefore, the control unit can determine whether the switch circuit has a fault in a short time.

[0033] In addition, this method is a structure that uses the wiring of the drive circuit of the semiconductor switch, the voltage-stabilizing diode for protecting the semiconductor switch, and the drive switch for driving the semiconductor switch as a discharge circuit. That is, the drive circuit also has the discharge function of the capacitor. Therefore, the control device involved in this method can suppress the increase in the number of components and discharge the capacitor efficiently, and can determine whether the switch circuit has a fault in a short time.

[0034] Furthermore, the control of switching the drive switch from off to on is the control of switching the semiconductor switch from on to off, and at the same time, the control of starting the discharge of the capacitor. Therefore, the control circuit can control the semiconductor switch and the discharge of the capacitor only by controlling the drive switch.

[0035] (2) It is preferable that the voltage detection unit includes a voltage dividing resistor for dividing the voltage at the one end of the switch circuit.

[0036] According to this embodiment, when the switch circuit is normally disconnected, the capacitor is disconnected from the vehicle-mounted battery, and the charge stored in the capacitor is discharged through the voltage-dividing resistor for voltage detection. Therefore, the capacitor can be discharged in a shorter time. Therefore, the control unit can determine whether the switch circuit has a fault in a short time.

[0037] (3) It is preferable that a discharge switch for grounding the one end of the switch circuit is provided, and the control unit controls the drive switch and the discharge switch from off to on.

[0038] According to this embodiment, when the switch circuit is normally disconnected, the capacitor is disconnected from the vehicle-mounted battery, and the charge stored in the capacitor is discharged through the discharge switch. Therefore, the capacitor can be discharged in a shorter time. Therefore, the control unit can determine whether the switch circuit has a fault in a short time.

[0039] (4) It is preferable that a resistor is provided in the wiring.

[0040] According to this aspect, the surge voltage and surge current returning from the outside to the control unit can be reduced by the resistor.

[0041] (5) It is preferable that the switch circuit includes a plurality of the semiconductor switches connected in parallel, and the control device includes a plurality of the Zener diodes and a plurality of the resistors provided in each of the plurality of semiconductor switches.

[0042] According to this aspect, the switch circuit includes a plurality of semiconductor switches connected in parallel, so that the control device can open and close a circuit in which a large current that cannot be controlled by a single semiconductor switch flows.

[0043] In addition, a Zener diode is provided in each of the plurality of semiconductor switches. The charge accumulated in the capacitor is discharged through the plurality of Zener diodes, wiring and drive switches. Therefore, the capacitor can be discharged in a shorter time. Therefore, the control unit can determine whether the switch circuit has a fault in a short time.

[0044] Furthermore, a resistor is provided in each of the plurality of semiconductor switches. Therefore, a surge voltage and a surge current returning from the outside to the control unit can be more effectively reduced. The resistor provided in each semiconductor switch can be miniaturized.

[0045] [Details of the embodiments of the present disclosure]

[0046] Hereinafter, a control device according to an embodiment of the present disclosure will be described with reference to the drawings. In addition, the present disclosure is not limited to these examples, but is indicated by the claims, and is intended to include all changes within the meaning and scope equivalent to the claims.

[0047] Hereinafter, the present disclosure will be described in detail based on the drawings showing embodiments thereof.

[0048] (Implementation Method 1)

[0049] Figure 1 1 is a circuit block diagram for explaining a configuration example of a vehicle current control system according to Embodiment 1. The vehicle current control system according to Embodiment 1 includes a vehicle control device 1, a starter generator (vehicle-mounted device) 2, a vehicle-mounted battery 3, and a load 4. The control device 1 includes a control unit 10, a switch circuit 11, a drive circuit 12, and a voltage detection unit 13. A first terminal 1a is connected to one end of the switch circuit 11, and a second terminal 1b is connected to the other end of the switch circuit 11. The first terminal 1a is connected to one end of the starter generator 2, and the other end of the starter generator 2 is grounded. The starter generator 2 has a power generation function in addition to a starter function for starting the engine of the vehicle, and includes an engine starting motor (MTR) 21 and a capacitor 22. One end of the capacitor 22 is connected to the first terminal 1a, and the other end of the capacitor 22 is grounded. The positive electrode of the vehicle-mounted battery 3 is connected to the second terminal 1b, and the negative electrode of the vehicle-mounted battery 3 is grounded. In addition, one end of the load 4 is connected to the second terminal 1b, and the other end of the load 4 is grounded. The load 4 is vehicle-mounted equipment such as interior lights, air conditioners, and a car navigation device.

[0050] In the vehicle current control system configured in this manner, the starter generator 2 is connected to the vehicle battery 3 and the load 4 via the control device 1. The control device 1 opens and closes the starter generator 2 and the vehicle battery 3.

[0051] When the vehicle engine is running and the starter generator 2 generates electricity, the starter generator 2 including the capacitor 22 is connected to the vehicle battery 3. The vehicle battery 3 and the capacitor 22 are charged by the power generation of the starter generator 2. When the starter generator 2 is not generating electricity and the capacitor 22 and the vehicle battery 3 are connected, the capacitor 22 is charged by the vehicle battery 3.

[0052] When the engine of the vehicle is stopped, the control device 1 opens the circuit and disconnects the starter generator 2 and the vehicle battery 3. When the engine is started in this state, the starter battery (not shown) connected to the starter generator 2 drives the motor 21 to start the engine. The drive of the motor 21 requires a large amount of power, but since the starter generator 2 is disconnected from the vehicle battery 3 and the load 4, it is possible to avoid undesirable conditions such as a voltage drop on the load 4 side. When the engine is started, the control device 1 closes the circuit and connects the starter generator 2 to the vehicle battery 3.

[0053] Figure 2 1 is a block diagram showing a configuration example of the control device 1 involved in Embodiment 1. The switch circuit 11 has at least one semiconductor switch 11a. The semiconductor switch 11a can use, for example, a MOSFET (Metal-Oxide-SemiconductorField-EffectTransistor), an IGBT (Insulated GateBipolarTransistor), etc. In the following, it is explained that the semiconductor switch 11a is an N-channel MOSFET. The drain of the semiconductor switch 11a is connected to the second terminal 1b, and the source is connected to the first terminal 1a.

[0054] The drive circuit 12 is a circuit for turning the semiconductor switch 11a on or off, and its operation is controlled by the control unit 10. The drive circuit 12 includes a drive power source 12a, wiring 12b, a first resistor 12c, a second resistor 12d, a drive switch 12e, and a Zener diode 12f.

[0055] The driving power supply 12a outputs a driving voltage for turning the semiconductor switch 11a on or off. The driving power supply 12a is connected to the gate of the semiconductor switch 11a via the wiring 12b and the first resistor 12c and the second resistor 12d connected in series. The wiring 12b is a conductive wire for connecting the driving power supply 12a to the gate of the semiconductor switch 11a. In detail, one end of the first resistor 12c is connected to the positive terminal of the driving power supply 12a through the wiring 12b, and the other end of the first resistor 12c is connected to one end of the second resistor 12d. The other end of the second resistor 12d is connected to the gate of the semiconductor switch 11a through the wiring 12b. In addition, the second resistor 12d is, for example, a resistor for surge protection.

[0056] The drive switch 12e is a switch for controlling the semiconductor switch 11a to be turned on or off. The drive switch 12e is, for example, a transistor switch. One end of the drive switch 12e is grounded, and the other end is connected to the other end of the first resistor 12c and one end of the second resistor 12d via the wiring 12b.

[0057] When a low-level signal is output from the control unit 10 to the drive switch 12e, the drive switch 12e is turned off. When the drive switch 12e is turned off, the drive voltage of the drive power supply 12a is applied to the gate of the semiconductor switch 11a through the wiring 12b, and the semiconductor switch 11a is turned on (refer to Figure 3 ).

[0058] When a high-level signal is output from the control unit 10 to the drive switch 12e, the drive switch 12e is turned on. When the drive switch 12e is turned on, the gate of the semiconductor switch 11a is grounded, and the semiconductor switch 11a is turned off (see Figure 4 ).

[0059] The control unit 10 is a computer including a CPU, a storage unit 10a, a timing unit 10b, an input / output unit 10c, etc. (not shown). The storage unit 10a stores information for determining whether the semiconductor switch 11a has a fault. In addition, the storage unit 10a stores the fault diagnosis result of the semiconductor switch 11a. The input / output unit 10c outputs a signal or data indicating the fault or the presence or absence of a fault of the semiconductor switch 11a to the outside.

[0060] The voltage detector 13 includes voltage-dividing resistors 13a and 13b connected in series. One end of the series circuit is connected to the first terminal 1a and the other end is grounded. The control unit 10 can detect the voltage of the first terminal 1a, that is, the first terminal 1a of the switch circuit 11, by acquiring the voltage divided by the voltage-dividing resistors 13a and 13b.

[0061] Figure 3 and Figure 4 is an explanatory diagram showing a method of determining a fault, Figure 5 is a timing diagram showing a method for diagnosing a short circuit fault. Figure 5 , the horizontal axis represents time. Figure 5 The vertical axis in A represents the on and off states of the semiconductor switch 11 a . Figure 5 The vertical axis in B represents the time change of the voltage VBATT of the first terminal 1 a detected by the voltage detection unit 13 when the semiconductor switch 11 a is not faulty. Figure 5 The vertical axis in C represents the time change of the voltage VBATT of the first terminal 1a detected by the voltage detection unit 13 when a short-circuit fault occurs in the semiconductor switch 11a. A short-circuit fault is a fault state in which the semiconductor switch 11a is always turned on regardless of the voltage applied to the gate. Figure 5 B and Figure 5 In C, the voltage V1 indicates a predetermined voltage of the vehicle-mounted battery 3 . The predetermined voltage is a rated voltage and is a constant that does not change depending on the state of the vehicle-mounted battery 3 .

[0062] When the semiconductor switch 11a is in the on state, Figure 3 As shown in FIG. 1 , the voltage of the first terminal 1a is the predetermined voltage V1 of the vehicle-mounted battery 3, and the voltage of the capacitor 22 is also the voltage V1. Figure 3 and Figure 4 , ΔV is the voltage between the gate and the source of the semiconductor switch 11a. The voltage at the gate of the semiconductor switch 11a is represented by V1+ΔV.

[0063] In the case where the semiconductor switch 11a is not faulty, when the semiconductor switch 11a changes from on to off, Figure 4 As shown, capacitor 22 is discharged (refer to Figure 1 Hollow arrow, Figure 4 Medium thick arrows and thin arrows), such as Figure 5 As shown in FIG. B, the voltage VBATT of the first terminal 1a decreases exponentially. More specifically, as Figure 4 As shown by the bold arrow in FIG. 1 , the charge accumulated in the capacitor 22 is discharged mainly through the Zener diode 12f, the second resistor 12d and the drive switch 12e. Figure 4 As indicated by thin arrows in FIG. 1 , a part of the charge accumulated in the capacitor 22 is discharged through the voltage-dividing resistors 13a and 13b of the voltage detection unit 13. Finally, the voltage of the first terminal 1a and the voltage of the gate of the semiconductor switch 11a become 0 [V].

[0064] When a short circuit occurs in the semiconductor switch 11a, the semiconductor switch 11a is always in the on state. Figure 5 As shown in FIG. 3C , the voltage VBATT of the first terminal 1 a is maintained at the voltage V1 .

[0065] The storage unit 10a of the control unit 10 stores a threshold value and a diagnostic waiting time for determining whether the semiconductor switch 11a has a fault. The diagnostic waiting time is the time required for the capacitor 22 charged by the vehicle battery 3 to discharge. The threshold voltage is the maximum voltage VBATT of the first terminal 1a detected when the fully charged capacitor 22 starts to discharge and a predetermined diagnostic waiting time has passed.

[0066] The control unit 10 controls the semiconductor switch 11a from on to off, and by comparing the voltage VBATT of the first terminal 1a after the diagnostic waiting time has passed after the semiconductor switch 11a is controlled from on to off with the threshold, it is possible to determine whether the semiconductor switch 11a has a short circuit fault. Specifically, the control unit 10 determines that the semiconductor switch 11a has not failed when the voltage VBATT of the first terminal 1a after the diagnostic waiting time has passed is less than the threshold. The control unit 10 determines that the semiconductor switch 11a has failed when the voltage VBATT of the first terminal 1a after the diagnostic waiting time has passed is greater than the threshold.

[0067] Figure 6 1 is a block diagram showing a configuration example of a control device 101 according to a comparative example. The control device 101 according to the comparative example includes a varistor 112f instead of the zener diode 12f constituting the control device 1 according to the first embodiment.

[0068] Fig. 7A and Figure 7B 2 is a timing chart showing the effect of the control device 1 according to the first embodiment. Fig. 7A and Figure 7B , the horizontal axis represents time. Fig. 7A The vertical axis in φ represents a temporal change in the voltage VBATT of the first terminal 1 a detected by the voltage detection unit 13 of the control device 1 according to the first embodiment when the semiconductor switch 11 a is not faulty. Figure 7B The vertical axis in represents the time change of the voltage VBATT of the first terminal 1 a detected by the voltage detection unit 13 of the control device 101 according to the comparative example when the semiconductor switch 11 a is not faulty.

[0069] In the control device 101 according to the comparative example, Figure 6 and Figure 7B As shown, the discharge path of the capacitor 22 is only the voltage detection unit 13. Compared with the control device 1 according to the first embodiment, the control device 101 according to the comparative example requires time to discharge the capacitor 22. Therefore, the control unit 10 according to the comparative example requires time to diagnose the failure of the switch circuit 11.

[0070] On the other hand, according to the present embodiment 1, if Figure 4 and Fig. 7AAs shown, the charge accumulated in the capacitor 22 is discharged from the drive circuit 12 in addition to the voltage detection unit 13. Therefore, the capacitor 22 is discharged in a shorter time than in the comparative example. Therefore, the control unit 10 can perform a fault diagnosis of the switch circuit 11 in a shorter time.

[0071] According to the control device 1 according to the first embodiment configured in this way, when the capacitor 22 of the starter generator 2 to be switched is connected, the capacitor 22 can be efficiently discharged to determine the presence or absence of a failure in the switching circuit 11 in a short time.

[0072] In addition, according to the control device 1 according to the first embodiment, the charge of the capacitor 22 can be discharged through the voltage detection unit 13 in addition to the drive circuit 12. Therefore, the capacitor 22 can be discharged in a shorter time. Therefore, the control unit 10 can determine whether the switch circuit 11 has a fault in a short time.

[0073] Furthermore, since the second resistor 12 d is provided, a surge voltage and a surge current returning from the outside to the control unit 10 can be reduced.

[0074] (Implementation Method 2)

[0075] The control device 201 according to the second embodiment is different from the first embodiment in that it further includes a discharge circuit 14, so the following mainly describes the above difference. Since other steps and effects are the same as those of the first embodiment, the same reference numerals are given to corresponding parts and detailed description is omitted.

[0076] Figure 8 1 is a block diagram showing a configuration example of a control device 201 according to Embodiment 2. The control device 201 according to Embodiment 2 includes the same components as the control device 1 according to Embodiment 1, and further includes a discharge circuit 14 for discharging the capacitor 22 .

[0077] The discharge circuit 14 includes a discharge switch 14a for grounding one end of the semiconductor switch 11a and a third resistor 14b. One end of the discharge switch 14a is grounded, and the other end of the discharge switch 14a is connected to one end of the third resistor 14b. The other end of the third resistor 14b is connected to one end of the switch 11a. The operation of the discharge switch 14a is controlled by the control unit 10.

[0078] The control unit 10 controls the drive switch 12e and the discharge switch 14a so that they are in the on state and the off state, respectively. For example, the control unit 10 controls the discharge switch 14a from off to on while controlling the drive switch 12e from off to on. In this case, the semiconductor switch 11a changes from on to off, and the capacitor 22 starts to discharge. The charge of the capacitor 22 is discharged through three discharge paths. The first discharge path is the drive circuit 12, the second discharge path is the voltage detection unit 13, and the third discharge path is the discharge circuit 14.

[0079] In addition, Figure 8 , an example is shown in which the control unit 10 outputs control signals to the drive switch 12e and the discharge switch 14a separately, but the control signals to the drive switch 12e and the discharge switch 14a may be shared. That is, the signal output from the control unit 10 may be input to both the drive switch 12e and the discharge switch 14a.

[0080] According to the control device 201 according to the second embodiment, compared with the first embodiment, the capacitor 22 can be discharged more efficiently and the presence or absence of a failure in the switching circuit 11 can be determined in a short time.

[0081] (Implementation 3)

[0082] The control device 301 according to the third embodiment is different from the first embodiment in that it has a plurality of semiconductor switches 11a connected in parallel and each of the plurality of semiconductor switches 11a is provided with a voltage stabilizing diode 12f, a second resistor 12d, and a drive switch 12e, so the following mainly describes the above-mentioned difference. Since other processes and effects are the same as those in the first embodiment, the same reference numerals are given to corresponding parts and detailed descriptions are omitted.

[0083] Fig. 9 1 is a block diagram showing a configuration example of a control device 301 according to Embodiment 3. The control device 301 according to Embodiment 3 includes a plurality of semiconductor switches 11a connected in parallel. In Embodiment 3, a switch circuit 311 in which three semiconductor switches 11a are connected in parallel is described, but the number of semiconductor switches 11a is not particularly limited to six.

[0084] The drive circuit 312 is a drive circuit 312 for turning on or off the plurality of semiconductor switches 11a, and the operation of the drive circuit 312 is controlled by the control unit 10. The drive circuit 312 includes a drive power supply 12a and a first resistor 12c. The drive circuit 312 includes wiring 12b that connects the drive power supply 12a to the gates of the plurality of semiconductor switches 11a. The drive circuit 312 includes a second resistor 12d, a drive switch 12e, and a Zener diode 12f for each of the plurality of semiconductor switches 11a.

[0085] The driving power source 12a is connected to the gates of the plurality of semiconductor switches 11a via the wiring 12b and the first resistor 12c and the second resistor 12d connected in series. The wiring 12b is a conductive line for connecting the driving power source 12a to the gates of the plurality of semiconductor switches 11a.

[0086] One end of each of the plurality of drive switches 12 e is grounded, and the other end is connected to the other end of the first resistor 12 c and one end of the second resistor 12 d associated with each semiconductor switch 11 a via a wiring 12 b .

[0087] According to the control device 301 according to the third embodiment, since the switch circuit 311 includes the plurality of semiconductor switches 11 a connected in parallel, the control device 301 can open and close a circuit in which a large current that cannot be controlled by a single semiconductor switch 11 a flows.

[0088] Furthermore, since the charge stored in the capacitor 22 is discharged through the plurality of Zener diodes 12f, the wiring 12b, and the drive switch 12e, the capacitor 22 can be discharged in a shorter time. Therefore, the control unit 10 can determine whether the switch circuit 311 is faulty in a shorter time.

[0089] Furthermore, the second resistor 12d is provided in each of the plurality of semiconductor switches 11a. Therefore, it is possible to more effectively reduce the surge voltage and surge current returning to the control unit 10. The second resistor 12d provided in each semiconductor switch 11a can be miniaturized.

[0090] Furthermore, the configuration according to the third embodiment may be applied to the second embodiment. In other words, the discharge circuit 14 according to the second embodiment may be provided in the control device 301 according to the third embodiment.

[0091] Description of Reference Numerals

[0092] 1, 201, 301 control device

[0093] 101 Control device according to comparative example

[0094] 1a First terminal

[0095] 1b Second terminal

[0096] 2 Starter generator

[0097] 3. Vehicle battery

[0098] 4 Load

[0099] 10. Control Unit

[0100] 10a Storage unit

[0101] 10b Timing Department

[0102] 10c Input and output section

[0103] 11.311 Switching Circuit

[0104] 11a Semiconductor switch

[0105] 12, 312 drive circuit

[0106] 12a drive power supply

[0107] 12b Wiring

[0108] 12c First resistor

[0109] 12d Second resistor

[0110] 12e Drive switch

[0111] 12f Zener diode

[0112] 112f Varistor

[0113] 13 Voltage detection unit

[0114] 13a, 13b voltage divider resistor

[0115] 14 Discharge circuit

[0116] 14a Discharge switch

[0117] 14b Third resistor

[0118] 21 Electric Motor

[0119] 22 Capacitor

[0120] 112f varistor.

Claims

1. A control device for a vehicle, comprising a switch circuit and controlling the on / off of the switch circuit to open and close a starter generator and an on-vehicle battery and a load, thereby preventing a voltage drop on the load side when the starter generator starts an engine, wherein the switch circuit comprises a semiconductor switch, the starter generator comprises a capacitor connected to one end of the switch circuit, and the on-vehicle battery and the load are connected to the other end of the switch circuit. The control device comprises: A driving power supply, outputting a driving voltage for driving the semiconductor switch on and off; Wiring, connecting the driving power source and the gate of the semiconductor switch, for applying the driving voltage to the gate of the semiconductor switch; a first resistor, one end of which is connected to the driving power source via the wiring; a second resistor having one end connected to the other end of the first resistor and the other end connected to the gate of the semiconductor switch via the wiring; a driving switch having one end connected to the ground and the other end connected to one end of the second resistor, for turning off the semiconductor switch by short-circuiting the wiring; a voltage stabilizing diode, wherein the anode is connected to the one end portion and the cathode is connected to the other end of the second resistor; a voltage detection unit for detecting a voltage at the one end portion; and The control unit determines whether the switch circuit has a fault by controlling the drive switch from off to on and comparing the voltage detected by the voltage detection unit with a predetermined threshold value.

2. The control device according to claim 1, wherein: The voltage detection unit includes a voltage dividing resistor that divides the voltage at the one end of the switch circuit.

3. The control device according to claim 1, wherein: The control device includes a discharge switch for grounding the one end of the switch circuit. The control unit controls the drive switch and the discharge switch from being off to being on.

4. The control device according to claim 2, wherein: The control device includes a discharge switch for grounding the one end of the switch circuit. The control unit controls the drive switch and the discharge switch from being off to being on.

5. The control device according to any one of claims 1 to 4, wherein: The switch circuit has a plurality of semiconductor switches connected in parallel. The control device includes a plurality of the Zener diodes and a plurality of the resistors provided in each of the plurality of semiconductor switches.

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