阅读说明：本技术 控制装置 (Control device ) 是由 若园佳佑 于 2020-04-06 设计创作，主要内容包括：车辆用的控制装置具备半导体开关,通过对半导体开关的接通和断开进行控制而对连接于半导体开关的一端部的电容器与连接于半导体开关的另一端部的车载蓄电池之间进行开闭。控制装置具备：配线,用于向半导体开关施加使半导体开关接通的驱动电压；驱动开关,用于使配线短路而使半导体开关断开；稳压二极管,阳极连接于一端部,阴极连接于配线；电压检测部,检测一端部的电压；及控制部,通过将驱动开关从断开控制成接通并对检测到的电压与阈值进行比较,来判定半导体开关有无故障。(The control device for a vehicle includes a semiconductor switch, and controls on/off of the semiconductor switch to open/close a capacitor connected to one end of the semiconductor switch and an in-vehicle battery connected to the other end of the semiconductor switch. The control device is provided with: a wiring for applying a drive voltage for turning on the semiconductor switch to the semiconductor switch; a drive switch for short-circuiting the wiring to turn off the semiconductor switch; a voltage regulator diode having an anode connected to one end and a cathode connected to a wiring; a voltage detection unit that detects a voltage at one end; and a control unit for controlling the drive switch from off to on and comparing the detected voltage with a threshold value to determine whether or not the semiconductor switch has a failure.)

1. A control device for a vehicle, which is provided with a switching circuit having a semiconductor switch, controls the on/off of the switching circuit, and opens and closes between an in-vehicle device having a capacitor connected to one end of the switching circuit and an in-vehicle battery connected to the other end of the switching circuit,

the control device is provided with:

a wiring for applying a drive voltage for turning on the semiconductor switch to a gate of the semiconductor switch;

a drive switch for short-circuiting the wiring to turn off the semiconductor switch;

a voltage regulator diode having an anode connected to the one end portion and a cathode connected to the wiring;

a voltage detection unit that detects a voltage at the one end portion; and

and a control unit that controls the drive switch from off to on and compares the voltage detected by the voltage detection unit with a predetermined threshold value to determine whether or not the switching circuit has a failure.

2. The control device according to claim 1,

the voltage detection unit includes a voltage dividing resistor that divides a voltage at the one end portion of the switching circuit.

3. The control device according to claim 1 or 2,

the control device includes a discharge switch for grounding the one end portion of the switching circuit,

the control unit controls the drive switch and the discharge switch from off to on.

4. The control device according to any one of claims 1 to 3,

the wiring is provided with a resistor.

5. The control device according to claim 4,

the switching circuit has a plurality of the semiconductor switches connected in parallel,

the control device includes a plurality of the zener diodes and a plurality of the resistors provided in the plurality of semiconductor switches, respectively.

Technical Field

The present disclosure relates to a control device.

The present application claims priority to japanese application No. 2019-085996 filed on 26/4/2019, and incorporates the entire contents of the japanese application.

Background

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

Documents of the prior art

Patent document

Patent document 1 Japanese patent laid-open No. 2005-39385

Disclosure of Invention

Problems to be solved by the invention

The present invention relates to a control device for a vehicle including a switching circuit having a semiconductor switch, the switching circuit controlling on/off of the switching circuit to open/close a gap between an in-vehicle device having a capacitor connected to one end of the switching circuit and an in-vehicle battery connected to the other end of the switching circuit, the control device including: a wiring for applying a drive voltage for turning on the semiconductor switch to a gate of the semiconductor switch; a drive switch for short-circuiting the wiring to turn off the semiconductor switch; a voltage regulator diode having an anode connected to the one end portion and a cathode connected to the wiring; a voltage detection unit that detects a voltage at the one end portion; and a control unit that controls the drive switch from off to on and compares the voltage detected by the voltage detection unit with a predetermined threshold value to determine whether or not the switching circuit has a failure.

The present application can be realized not only as a control unit including such a characteristic processing unit, but also as a control method including the above-described characteristic processing as a step, or as a program for causing a computer to execute the above-described step. In addition, the present invention can be implemented as a semiconductor integrated circuit in which a part or all of the control device is implemented, or as another system including the control device.

Drawings

Fig. 1 is a circuit block diagram illustrating a configuration example of a vehicle current control system according to embodiment 1.

Fig. 2 is a block diagram showing an example of the configuration of the control device according to embodiment 1.

Fig. 3 is an explanatory diagram showing a failure determination method.

Fig. 4 is an explanatory diagram showing a failure determination method.

Fig. 5 is a timing chart showing a diagnostic method of a short-circuit fault.

Fig. 6 is a block diagram showing an example of the configuration of the control device according to the comparative example.

Fig. 7A is a timing chart showing the effect of the control device according to embodiment 1.

Fig. 7B is a timing chart showing the effect of the control device according to embodiment 1.

Fig. 8 is a block diagram showing an example of the configuration of the control device according to embodiment 2.

Fig. 9 is a block diagram showing an example of the configuration of the control device according to embodiment 3.

Detailed Description

[ problems to be solved by the present disclosure ]

In the vehicle control device according to patent document 1, when a capacitor is connected to a circuit of an in-vehicle device to be controlled for opening and closing, if the capacitor has a large capacitance, it takes time to discharge the capacitor and time to diagnose a failure of the switching circuit.

For example, in the case where the starter having the capacitor and the in-vehicle battery are configured to be opened and closed by the switching circuit, even if the switching circuit in the on state is turned off, it takes time until the capacitor is discharged and the voltage is reduced, and as a result, it takes time to diagnose whether or not the switching circuit is operating normally.

An object of the present disclosure is to provide a control device capable of efficiently discharging a capacitor when the capacitor of an in-vehicle device to be controlled is connected, and determining whether or not a failure has occurred in a switching circuit in a short time.

[ Effect of the present disclosure ]

According to the present disclosure, it is possible to provide a control device that can efficiently discharge a capacitor and determine whether or not a failure has occurred in a switching circuit in a short time when the capacitor of an in-vehicle device that is an object to be controlled for switching is connected.

[ description of embodiments of the present disclosure ]

First, embodiments describing the present disclosure will be described. At least some of the embodiments described below may be arbitrarily combined.

(1) The present invention relates to a control device for a vehicle including a switching circuit having a semiconductor switch, the switching circuit controlling on/off of the switching circuit to open/close a gap between an in-vehicle device having a capacitor connected to one end of the switching circuit and an in-vehicle battery connected to the other end of the switching circuit, the control device including: a wiring for applying a drive voltage for turning on the semiconductor switch to a gate of the semiconductor switch; a drive switch for short-circuiting the wiring to turn off the semiconductor switch; a voltage regulator diode having an anode connected to the one end portion and a cathode connected to the wiring; a voltage detection unit that detects a voltage at the one end portion; and a control unit that controls the drive switch from off to on and compares the voltage detected by the voltage detection unit with a predetermined threshold value to determine whether or not the switching circuit has a failure.

According to this aspect, the control unit can determine whether or not the switching circuit has a failure in a time shorter than the time required to completely discharge the capacitor charged in the in-vehicle battery.

When the presence or absence of a failure in the switching circuit is determined, the control unit controls the drive switch from off to on. When the drive switch is off, the semiconductor switch is turned on (see fig. 3). When the drive switch is turned on, the semiconductor switch is turned off (see fig. 4). When the switching circuit is turned on, the capacitor is connected to the in-vehicle battery, and the capacitor is charged. When the switching circuit is normally turned off by the control of the drive switch, the capacitor is disconnected from the in-vehicle battery, and the capacitor starts to be discharged (see fig. 4).

When the capacitor is discharged to lower the voltage at the one end portion of the switching circuit to the reference potential, it can be determined that the switching circuit is normally controlled from on to off.

In particular, according to this embodiment, the electric charge stored in the capacitor is discharged through the zener diode, the wiring, and the drive switch. Therefore, the capacitor can be discharged in a shorter time than in the case where the capacitor is naturally discharged. Therefore, the control unit can determine whether or not the switching circuit has a failure in a short time.

In addition, in this embodiment, the wiring of the drive circuit constituting the semiconductor switch, the zener diode for protecting the semiconductor switch, and the drive switch for driving the semiconductor switch are used as the discharge circuit. That is, the driving circuit also has a discharging function of the capacitor. Therefore, the control device according to this aspect can efficiently discharge the capacitor while suppressing an increase in the number of components, and can determine the presence or absence of a failure in the switching circuit in a short time.

Further, the control of turning the drive switch from off to on is the control of switching the semiconductor switch from on to off, and is also the control of starting the discharge of the capacitor. Therefore, the control circuit can control the semiconductor switch and control the discharge of the capacitor only by controlling the drive switch.

(2) Preferably, the voltage detection unit includes a voltage dividing resistor that divides the voltage at the one end portion of the switching circuit.

According to this aspect, when the switching circuit is normally turned off, the capacitor is disconnected from the in-vehicle battery, and the electric 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 or not the switching circuit has a failure in a short time.

(3) Preferably, the discharge switch is provided to ground the one end portion of the switching circuit, and the control unit controls the drive switch and the discharge switch from off to on.

According to this aspect, when the switching circuit is normally off, the capacitor is disconnected from the in-vehicle battery, and the charge stored in the capacitor is also discharged by the discharge switch. Therefore, the capacitor can be discharged in a shorter time. Therefore, the control unit can determine whether or not the switching circuit has a failure in a short time.

(4) Preferably, the wiring is provided with a resistor.

According to this aspect, the resistor can reduce a surge voltage and a surge current returned from the outside to the control unit.

(5) Preferably, the switching 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 the plurality of the semiconductor switches, respectively.

According to this aspect, the switching circuit includes a plurality of semiconductor switches connected in parallel. Therefore, the control device can open and close a circuit through which a large current that cannot be controlled by one semiconductor switch flows.

Further, a zener diode is provided in each of the plurality of semiconductor switches. The electric charge accumulated in the capacitor is discharged through the plurality of zener diodes, the wiring, and the drive switch. Therefore, the capacitor can be discharged in a shorter time. Therefore, the control unit can determine whether or not the switching circuit has a failure in a short time.

Further, a resistor is provided in each of the plurality of semiconductor switches. Therefore, the surge voltage and the surge current returned from the outside to the control unit can be reduced more effectively. The resistors provided in the semiconductor switches can be miniaturized.

[ details of embodiments of the present disclosure ]

Hereinafter, a control device according to an embodiment of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to these examples, but is defined by the claims, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

The present disclosure will be specifically described below with reference to the drawings showing embodiments thereof.

(embodiment mode 1)

Fig. 1 is a circuit block diagram illustrating 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 (in-vehicle device) 2, an in-vehicle battery 3, and a load 4. The control device 1 includes a control unit 10, a switching 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 of starting an 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 in-vehicle battery 3 is connected to the second terminal 1b, and the negative electrode of the in-vehicle battery 3 is grounded. 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 a vehicle-mounted device such as an interior light, an air conditioner, and a car navigation device.

In the vehicle current control system configured as described above, the starter generator 2 is connected to the vehicle-mounted battery 3 and the load 4 via the control device 1. The control device 1 opens and closes between the starter generator 2 and the in-vehicle battery 3.

When the engine of the vehicle is operated to generate electric power by the starter generator 2, the starter generator 2 including the capacitor 22 is connected to the vehicle-mounted battery 3. The on-vehicle battery 3 and the capacitor 22 are charged by the power generation of the starter generator 2. When the capacitor 22 and the vehicle-mounted battery 3 are connected even when the starter generator 2 is not generating power, the capacitor 22 is charged by the vehicle-mounted battery 3.

When the engine of the vehicle is stopped, the control device 1 opens the electric circuit to cut off the starter generator 2 and the vehicle-mounted battery 3. When the engine is started in this state, the electric motor 21 is driven by a starter battery, not shown, connected to the starter generator 2, to start the engine. The drive of the electric motor 21 requires a large amount of electric power, but since the starter generator 2 is disconnected from the in-vehicle battery 3 and the load 4, it is possible to avoid a problem such as a voltage drop on the load 4 side. When the engine is started, the control device 1 closes the electric circuit to connect the starter generator 2 and the vehicle-mounted battery 3.

Fig. 2 is a block diagram showing an example of the configuration of the control device 1 according to embodiment 1. The switching circuit 11 has at least one semiconductor switch 11 a. For example, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), an IGBT (Insulated Gate Bipolar Transistor), or the like can be used as the Semiconductor switch 11 a. Hereinafter, the semiconductor switch 11a will be described as an N-channel MOSFET. The semiconductor switch 11a has a drain connected to the second terminal 1b and a source connected to the first terminal 1 a.

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

The drive power supply 12a outputs a drive voltage for turning on or off the drive of the semiconductor switch 11 a. The drive power source 12a is connected to the gate of the semiconductor switch 11a via a line 12b and a first resistor 12c and a second resistor 12d connected in series. The wiring 12b is a conductive line for connecting the driving power source 12a and the gate of the semiconductor switch 11 a. Specifically, one end of the first resistor 12c is connected to the positive terminal of the driving power source 12a via the wiring 12b, and the other end of the first resistor 12c is connected to one end of the second resistor 12 d. The other end of the second resistor 12d is connected to the gate of the semiconductor switch 11a through a wire 12 b. The second resistor 12d is, for example, a surge preventing resistor.

The drive switch 12e is a switch for on/off controlling the semiconductor switch 11 a. 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 a wire 12 b.

When the control unit 10 outputs a low-level signal to the drive switch 12e, the drive switch 12e is turned off. When the drive switch 12e is turned off, a drive voltage of the drive power source 12a is applied to the gate of the semiconductor switch 11a through the wiring 12b, and the semiconductor switch 11a is turned on (see fig. 3).

When the control unit 10 outputs a high-level signal 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 fig. 4).

The control unit 10 is a computer having a CPU, a storage unit 10a, a timer unit 10b, an input/output unit 10c, and the like, which are not shown. The storage unit 10a stores information for determining whether or not the semiconductor switch 11a has a failure. The storage unit 10a stores the result of the failure diagnosis of the semiconductor switch 11 a. The input/output unit 10c externally outputs signals or data indicating the presence or absence of a failure of the semiconductor switch 11 a.

The voltage detection unit 13 includes voltage dividing resistors 13a and 13b connected in series, and 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 obtaining the voltage divided by the voltage dividing resistors 13a and 13 b.

Fig. 3 and 4 are explanatory views illustrating a failure determination method, and fig. 5 is a timing chart illustrating a short-circuit failure diagnosis method. In fig. 5, the horizontal axis represents time. The vertical axis in fig. 5A represents the on-off state of the semiconductor switch 11 a. The vertical axis in fig. 5B represents a temporal change in the voltage VBATT of the first terminal 1a detected by the voltage detection section 13 in the case where the semiconductor switch 11a is not failed. The vertical axis in fig. 5C represents a temporal change in the voltage VBATT of the first terminal 1a detected by the voltage detection section 13 in the case where the short-circuit failure occurs in the semiconductor switch 11 a. The short-circuit fault is a fault state in which the semiconductor switch 11a is always on regardless of the voltage applied to the gate thereof. In fig. 5B and 5C, the voltage V1 represents 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 in-vehicle battery 3.

When the semiconductor switch 11a is in the on state, as shown in fig. 3, the voltage of the first terminal 1a is a predetermined voltage V1 of the vehicle-mounted battery 3, and the voltage of the capacitor 22 is also a voltage V1. In fig. 3 and 4, Δ V is a voltage between the gate and the source of the semiconductor switch 11 a. The voltage of the gate of the semiconductor switch 11a is represented by V1+ Δ V.

When the semiconductor switch 11a is turned off from on without failure of the semiconductor switch 11a, the capacitor 22 is discharged as shown in fig. 4 (see hollow arrows in fig. 1, thick line arrows and thin line arrows in fig. 4), and the voltage VBATT of the first terminal 1a decreases exponentially and functionally as shown in fig. 5B. More specifically, as shown by the thick line arrows in fig. 4, the electric charge accumulated in the capacitor 22 is mainly discharged via the zener diode 12f, the second resistor 12d, and the drive switch 12 e. As shown by thin line arrows in fig. 4, part of the electric charge stored in the capacitor 22 is discharged by the voltage dividing resistors 13a and 13b of the voltage detector 13. Finally, the voltage of the first terminal 1a and the voltage of the gate of the semiconductor switch 11a become 0[ V ].

When the short-circuit fault occurs in the semiconductor switch 11a, the semiconductor switch 11a is always in the on state, and the voltage VBATT of the first terminal 1a is maintained at the voltage V1 as shown in fig. 5C.

The storage unit 10a of the control unit 10 stores a threshold value and a diagnosis waiting time for determining whether or not the semiconductor switch 11a has a failure. The diagnosis waiting time is a time required for discharging the capacitor 22 charged by the in-vehicle battery 3. The threshold voltage is the maximum voltage VBATT of the first terminal 1a detected when the fully charged capacitor 22 starts discharging and a predetermined diagnostic waiting time has elapsed.

The control unit 10 controls the semiconductor switch 11a from on to off, and compares the voltage VBATT of the first terminal 1a with a threshold value when the diagnostic waiting time has elapsed after the conductor switch is controlled from on to off, thereby making it possible to determine whether or not 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 elapsed is less than the threshold value. 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 elapsed is equal to or greater than a threshold value.

Fig. 6 is a block diagram showing an example of the configuration of the control device 101 according to the 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 embodiment 1.

Fig. 7A and 7B are timing charts showing effects of the control device 1 according to embodiment 1. In fig. 7A and 7B, the horizontal axis represents time. The vertical axis in fig. 7A represents a temporal change in the voltage VBATT of the first terminal 1a detected by the voltage detection unit 13 of the control device 1 according to embodiment 1 when the semiconductor switch 11a is not failed. The vertical axis in fig. 7B represents a temporal change in the voltage VBATT of the first terminal 1a detected by the voltage detection unit 13 of the control device 101 according to the comparative example when the semiconductor switch 11a has not failed.

In the control device 101 according to the comparative example, as shown in fig. 6 and 7B, the discharge path of the capacitor 22 is only the voltage detection unit 13. The control device 101 according to the comparative example requires time for discharging the capacitor 22, as compared with the control device 1 according to embodiment 1. Therefore, the control unit 10 according to the comparative example requires time for failure diagnosis of the switching circuit 11.

On the other hand, according to embodiment 1, as shown in fig. 4 and 7A, the electric charge stored 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 short time as compared with the comparative example. Therefore, the control unit 10 can perform the failure diagnosis of the switching circuit 11 in a short time.

According to the control device 1 according to embodiment 1 configured as described above, when the capacitor 22 of the starter generator 2 to be subjected to the switching control is connected, the capacitor 22 can be efficiently discharged to determine whether or not the switching circuit 11 has a failure in a short time.

Further, according to the control device 1 of embodiment 1, the electric charge of the capacitor 22 can be discharged by 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 or not the switching circuit 11 has a failure in a short time.

Further, since the second resistor 12d is provided, the surge voltage and the surge current returned from the outside to the control unit 10 can be reduced.

(embodiment mode 2)

The control device 201 according to embodiment 2 differs from embodiment 1 in that it further includes the discharge circuit 14, and therefore the above-described difference is mainly described below. Since other steps and operational effects are the same as those in embodiment 1, the same reference numerals are given to corresponding parts, and detailed description thereof is omitted.

Fig. 8 is a block diagram showing an example of the configuration of the control device 201 according to embodiment 2. The control device 201 according to embodiment 2 includes the same components as those of the control device 1 according to embodiment 1, and further includes a discharge circuit 14 that discharges the capacitor 22.

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

The control unit 10 controls the drive switch 12e and the discharge switch 14a to be in the on state and the off state, respectively. For example, the control unit 10 controls the drive switch 12e from off to on and also controls the discharge switch 14a from off to on. In this case, the semiconductor switch 11a is turned off from on, and the capacitor 22 starts discharging. 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 section 13, and the third discharge path is the discharge circuit 14.

In fig. 8, an example is shown in which the control unit 10 outputs a control signal to the drive switch 12e and the discharge switch 14a individually, but the control signal 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 14 a.

According to the control device 201 according to embodiment 2, the capacitor 22 can be more efficiently discharged than in embodiment 1, and the presence or absence of a failure in the switching circuit 11 can be determined in a short time.

(embodiment mode 3)

The control device 301 according to embodiment 3 differs from embodiment 1 in that it includes a plurality of semiconductor switches 11a connected in parallel, and the plurality of semiconductor switches 11a are provided with a zener diode 12f, a second resistor 12d, and a drive switch 12e, respectively, and therefore the above-described difference is mainly described below. Since other steps and operational effects are the same as those in embodiment 1, the same reference numerals are given to corresponding parts, and detailed description thereof is omitted.

Fig. 9 is a block diagram showing an example of the configuration of the 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, the switching circuit 311 in which three semiconductor switches 11a are connected in parallel will be described, but the number of semiconductor switches 11a is not particularly limited to six.

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 source 12a and a first resistor 12 c. The drive circuit 312 includes a wiring 12b for connecting the drive power source 12a to the gates of the semiconductor switches 11a, respectively. The drive circuit 312 includes a second resistor 12d, a drive switch 12e, and a zener diode 12f for each semiconductor switch 11a of the plurality of semiconductor switches 11 a.

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

One end of each of the plurality of driving switches 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 of each semiconductor switch 11a via a wire 12 b.

According to the control device 301 according to embodiment 3, since the switch circuit 311 includes the plurality of semiconductor switches 11a connected in parallel, the control device 301 can open and close a circuit through which a large current that cannot be controlled by one semiconductor switch 11a flows.

Further, since the electric 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 or not the switch circuit 311 has a failure in a short time.

Further, the plurality of semiconductor switches 11a are provided with second resistors 12d, respectively. Therefore, the surge voltage and the surge current returned to the control unit 10 can be reduced more effectively. The second resistor 12d provided in each semiconductor switch 11a can be miniaturized.

The configuration according to embodiment 3 may be applied to embodiment 2. In other words, the control device 301 according to embodiment 3 may be provided with the discharge circuit 14 according to embodiment 2.

Description of the reference numerals

1. 201, 301 control device

101 control device according to comparative example

1a first terminal

1b second terminal

2 Starter generator

3 vehicle-mounted storage battery

4 load

10 control part

10a storage part

10b timer

10c input/output unit

11. 311 switching circuit

11a semiconductor switch

12. 312 drive circuit

12a drive power supply

12b wiring

12c first resistor

12d second resistor

12e drive switch

12f voltage stabilizing diode

112f piezoresistor

13 Voltage detection part

13a, 13b voltage dividing resistor

14 discharge circuit

14a discharge switch

14b third resistor

21 electric motor

22 capacitor

112f piezoresistor.