JP7715691B2 - Solenoid valve drive control device - Google Patents

Description

The present invention relates to a solenoid valve drive control device that controls the drive of a solenoid valve having multiple drive coils.

A solenoid valve drive control device that controls the drive of a solenoid valve having multiple drive coils is disclosed, for example, in Patent Document 1. Such a solenoid valve drive control device is equipped with a control circuit that controls the energization of the drive coils. The control circuit controls the energization of the multiple drive coils. For example, if the solenoid valve is a double solenoid valve with two drive coils, the control circuit controls the energization of the two drive coils so that the two drive coils are alternately energized. This causes the valve element of the solenoid valve to operate, switching the flow of the fluid through the flow path.

Japanese Patent Application Laid-Open No. 2007-177818

However, in such solenoid valve drive control devices, due to considerations such as miniaturization of the solenoid valve drive control device and space constraints for arranging the control circuits, it is difficult to provide a control circuit for each of the multiple drive coils. Therefore, as in Patent Document 1, it is desirable to control the energization of multiple drive coils with a single control circuit. Furthermore, in such solenoid valve drive control devices, there is a desire to minimize the number of wirings. Therefore, it is desirable to achieve drive control of a solenoid valve having multiple drive coils with a single control circuit without causing malfunction of the solenoid valve, while still reducing the number of wirings.

The solenoid valve drive control device that solves the above problem is a solenoid valve drive control device that controls the drive of a solenoid valve having multiple drive coils, and includes one control circuit that controls the energization of the multiple drive coils and has only one ground terminal; multiple switching elements that are provided corresponding to the multiple drive coils and that control the on/off of energization to each of the drive coils; a common positive wiring that is electrically connected in common to the first end of each of the multiple drive coils and is also electrically connected to the control circuit; and multiple negative wiring that are provided corresponding to the multiple drive coils and are electrically connected to the second end of each of the multiple drive coils. a plurality of constant voltage circuits, each corresponding to the plurality of negative wirings, that are provided between the common positive wiring and each of the negative wirings to apply a constant voltage from the common positive wiring to the control circuit; a plurality of branch wirings, each corresponding to the plurality of negative wirings, that are electrically connected to the ground terminal and branch off from the ground terminal and are electrically connected to each of the plurality of negative wirings; and a current interruption element, each provided in each of the branch wirings, that interrupts current flowing from each of the negative wirings through each of the branch wirings toward the branch point of the branch wiring to the ground terminal.

In the electromagnetic valve drive control device, the current interrupting element may be a diode.
In the electromagnetic valve drive control device, the current interrupting element may be a switching element.

This invention allows for the drive control of a solenoid valve having multiple drive coils to be achieved with a single control circuit, without causing malfunction of the solenoid valve, while reducing the number of wires.

1 is a circuit diagram for explaining an electromagnetic valve drive control device according to a first embodiment. FIG. 2 is a circuit diagram for explaining a flow of current. FIG. 2 is a circuit diagram for explaining a flow of current. FIG. 10 is a circuit diagram for explaining a solenoid valve drive control device according to a second embodiment. FIG. 2 is a circuit diagram for explaining a flow of current. FIG. 2 is a circuit diagram for explaining a flow of current.

[First embodiment]
A first embodiment of a solenoid valve drive control device will be described below with reference to FIGS.

<Solenoid valve 10>
As shown in Figure 1, the solenoid valve 10 has a first drive coil 11 and a second drive coil 12. Therefore, the solenoid valve 10 of this embodiment is a double solenoid type having two drive coils. The solenoid valve 10 is configured so that, when current is alternately applied to the first drive coil 11 and the second drive coil 12, a valve element (not shown) operates to switch the flow of the fluid through the flow path. Because this type of solenoid valve 10 is already known, a detailed description of its configuration will be omitted.

<Overall configuration of solenoid valve drive control device 20>
The solenoid valve drive control device 20 controls the drive of the solenoid valve 10 having the first drive coil 11 and the second drive coil 12. Therefore, the solenoid valve drive control device 20 controls the drive of the solenoid valve 10 having a plurality of drive coils. The solenoid valve drive control device 20 controls the drive of the solenoid valve 10 based on a drive signal from an external control device 15.

The solenoid valve drive control device 20 includes one control circuit 21. The control circuit 21 controls the energization of the first drive coil 11 and the second drive coil 12. The control circuit 21 is, for example, an MPU (Micro Processor Unit). The control circuit 21 includes memory composed of a read-only memory (ROM) that pre-stores various programs and maps, and a random access memory (RAM) that temporarily stores calculation results, etc. Furthermore, the control circuit 21 includes a timer counter, an input interface, an output interface, etc.

The control circuit 21 has a power input terminal 22, a first signal input terminal 23, a second signal input terminal 24, a first signal output terminal 25, a second signal output terminal 26, and a ground terminal 27. Therefore, the control circuit 21 has only one ground terminal 27.

The solenoid valve drive control device 20 is equipped with a common positive wiring 30. A first end of the common positive wiring 30 is electrically connected to the positive terminal 16 of the external control device 15. A second end of the common positive wiring 30 is electrically connected in common to the first end of the first drive coil 11 and the first end of the second drive coil 12.

The solenoid valve drive control device 20 is equipped with negative wiring, that is, a first negative wiring 31 and a second negative wiring 32. The first negative wiring 31 is provided corresponding to the first drive coil 11. The second negative wiring 32 is provided corresponding to the second drive coil 12.

The first end of the first negative electrode wiring 31 is electrically connected to the first negative electrode terminal 17 of the external control device 15. The second end of the first negative electrode wiring 31 is electrically connected to the second end of the first drive coil 11. The first end of the second negative electrode wiring 32 is electrically connected to the second negative electrode terminal 18 of the external control device 15. The second end of the second negative electrode wiring 32 is electrically connected to the second end of the second drive coil 12. Therefore, the solenoid valve drive control device 20 has a plurality of negative electrode wirings, one for each of the drive coils, connected to the second ends of the drive coils.

The common positive wiring 30 is electrically connected to the first negative wiring 31 via a first resistor R1 and a first Zener diode ZD1. The cathode terminal of the first Zener diode ZD1 is electrically connected to the first resistor R1. The anode terminal of the first Zener diode ZD1 is electrically connected to the first negative wiring 31. A first capacitor C1 is connected in parallel to the first Zener diode ZD1.

A first connection line 33 is electrically connected to the midpoint between the first resistor R1 and the first Zener diode ZD1. A first end of the first connection line 33 is electrically connected to the midpoint between the first resistor R1 and the first Zener diode ZD1. A second end of the first connection line 33 is electrically connected to the anode terminal of the first diode D1. A cathode terminal of the first diode D1 is electrically connected to the circuit power supply line 34. A first signal line 35 is connected to the middle of the first connection line 33. A first end of the first signal line 35 is electrically connected to the middle of the first connection line 33. A second end of the first signal line 35 is electrically connected to the first signal input terminal 23.

The first Zener diode ZD1 and the first capacitor C1 constitute a first constant voltage circuit 41, which is a constant voltage circuit provided between the common positive wiring 30 and the first negative wiring 31. The first constant voltage circuit 41 is provided between the common positive wiring 30 and the first negative wiring 31 to apply a constant voltage from the common positive wiring 30 to the control circuit 21.

The common positive wiring 30 is electrically connected to the second negative wiring 32 via a second resistor R2 and a second Zener diode ZD2. The cathode terminal of the second Zener diode ZD2 is electrically connected to the second resistor R2. The anode terminal of the second Zener diode ZD2 is electrically connected to the second negative wiring 32. A second capacitor C2 is connected in parallel to the second Zener diode ZD2.

A second connection line 36 is electrically connected to the midpoint between the second resistor R2 and the second Zener diode ZD2. A first end of the second connection line 36 is electrically connected to the midpoint between the second resistor R2 and the second Zener diode ZD2. A second end of the second connection line 36 is electrically connected to the anode terminal of the second diode D2. A cathode terminal of the second diode D2 is electrically connected to the circuit power supply line 34. The circuit power supply line 34 is electrically connected to the power supply input terminal 22. A second signal line 37 is connected to the middle of the second connection line 36. A first end of the second signal line 37 is electrically connected to the middle of the second connection line 36. A second end of the second signal line 37 is electrically connected to the second signal input terminal 24.

The second Zener diode ZD2 and the second capacitor C2 constitute a second constant voltage circuit 42, which is a constant voltage circuit provided between the common positive wiring 30 and the second negative wiring 32. The second constant voltage circuit 42 is provided between the common positive wiring 30 and the second negative wiring 32 to apply a constant voltage from the common positive wiring 30 to the control circuit 21.

Therefore, multiple constant voltage circuits are provided, one for each of the multiple negative wirings. Furthermore, multiple constant voltage circuits are provided between the common positive wiring 30 and each negative wiring to apply a constant voltage from the common positive wiring 30 to the control circuit 21.

The solenoid valve drive control device 20 is equipped with a first switching element 51 and a second switching element 52. The first switching element 51 is provided corresponding to the first drive coil 11. The second switching element 52 is provided corresponding to the second drive coil 12. Therefore, one switching element is provided corresponding to each of the multiple drive coils.

The first switching element 51 is provided on the first negative wiring 31. The first switching element 51 is an n-channel MOSFET (metal-oxide-semiconductor field-effect transistor). The gate terminal of the first switching element 51 is electrically connected to the first signal output terminal 25 via the third resistor R3. The drain terminal of the first switching element 51 is electrically connected to the second end of the first drive coil 11. The source terminal of the first switching element 51 is electrically connected to the first negative terminal 17 of the external control device 15. The first switching element 51 has a first body diode 51a.

The second switching element 52 is provided on the second negative wiring 32. The second switching element 52 is an n-channel MOSFET (metal-oxide-semiconductor field-effect transistor). The gate terminal of the second switching element 52 is electrically connected to the second signal output terminal 26 via the fourth resistor R4. The drain terminal of the second switching element 52 is electrically connected to the second end of the second drive coil 12. The source terminal of the second switching element 52 is electrically connected to the second negative terminal 18 of the external control device 15. The second switching element 52 has a second body diode 52a.

As shown in FIG. 2, for example, assume that the first negative terminal 17 of the external control device 15 is in the ON state and the second negative terminal 18 is in the OFF state. In this case, current flows from the positive terminal 16 of the external control device 15 through the common positive wiring 30, the first resistor R1, the first Zener diode ZD1, the first negative wiring 31, and the first negative terminal 17 in this order. Power is then supplied to the power input terminal 22 via the first connection line 33, the first diode D1, and the circuit power line 34. This drives the control circuit 21. Furthermore, a drive signal is input to the first signal input terminal 23 via the first connection line 33 and the first signal line 35.

When a drive signal is input to the first signal input terminal 23, the control circuit 21 outputs a signal from the first signal output terminal 25 to the first switching element 51. This switches the first switching element 51 to the ON state. Therefore, when a signal is output from the first signal output terminal 25, the first switching element 51 is in the ON state. When no signal is output from the first signal output terminal 25, the first switching element 51 is in the OFF state. The signal output from the first signal output terminal 25 is a PWM control signal.

When the first switching element 51 is turned on, current flows from the positive terminal 16 of the external control device 15 through the common positive wiring 30, the first drive coil 11, the first negative wiring 31, and the first negative terminal 17 in this order. This allows current to flow through the first drive coil 11. On the other hand, when the first switching element 51 is turned off, current to the first drive coil 11 is cut off. In this way, the first switching element 51 controls the on/off flow of current to the first drive coil 11.

As shown in FIG. 3, for example, assume that the first negative terminal 17 of the external control device 15 is in the OFF state and the second negative terminal 18 is in the ON state. In this case, current flows from the positive terminal 16 of the external control device 15 through the common positive wiring 30, the second resistor R2, the second Zener diode ZD2, the second negative wiring 32, and the second negative terminal 18 in this order. Power is then supplied to the power supply input terminal 22 via the second connection line 36, the second diode D2, and the circuit power line 34. This drives the control circuit 21. Furthermore, a drive signal is input to the second signal input terminal 24 via the second connection line 36 and the second signal line 37.

When a drive signal is input to the second signal input terminal 24, the control circuit 21 outputs a signal from the second signal output terminal 26 to the second switching element 52. This switches the second switching element 52 to the ON state. Therefore, when a signal is output from the second signal output terminal 26, the second switching element 52 is in the ON state. When no signal is output from the second signal output terminal 26, the second switching element 52 is in the OFF state. The signal output from the second signal output terminal 26 is a PWM control signal.

When the second switching element 52 is turned on, current flows from the positive terminal 16 of the external control device 15 through the common positive wiring 30, the second drive coil 12, the second negative wiring 32, and the second negative terminal 18 in this order. This causes current to flow through the second drive coil 12. On the other hand, when the second switching element 52 is turned off, current to the second drive coil 12 is cut off. In this way, the second switching element 52 controls the on/off flow of current to the second drive coil 12. Therefore, the solenoid valve drive control device 20 is equipped with multiple switching elements that control the on/off flow of current to each drive coil.

<First Branch Wiring 61 and Second Branch Wiring 62>
As shown in FIG. 1 , the solenoid valve drive control device 20 includes branch wirings, that is, a first branch wiring 61 and a second branch wiring 62. The first branch wiring 61 is provided corresponding to the first negative electrode wiring 31. The first branch wiring 61 is electrically connected to the ground terminal 27. The first branch wiring 61 branches from the ground terminal 27 and is electrically connected to the first negative electrode wiring 31. The second branch wiring 62 is provided corresponding to the second negative electrode wiring 32. The second branch wiring 62 is electrically connected to the ground terminal 27. The second branch wiring 62 branches from the ground terminal 27 and is electrically connected to the second negative electrode wiring 32. Therefore, the branch wirings are provided one by one corresponding to the multiple negative electrode wirings, are electrically connected to the ground terminal 27, and branch from the ground terminal 27 to be electrically connected to the multiple negative electrode wirings, respectively.

As shown in FIG. 2, for example, assume that the first negative terminal 17 of the external control device 15 is in the ON state and the second negative terminal 18 is in the OFF state. In this case, current flowing from the ground terminal 27 flows to the first negative terminal 17 of the external control device 15 via the first branch wiring 61 and the first negative wiring 31.

As shown in FIG. 3, for example, assume that the first negative terminal 17 of the external control device 15 is in the OFF state and the second negative terminal 18 is in the ON state. In this case, current flowing from the ground terminal 27 flows to the second negative terminal 18 of the external control device 15 via the second branch wiring 62 and the second negative wiring 32.

<First current interrupting element 71 and second current interrupting element 72>
As shown in FIG. 1 , the solenoid valve drive control device 20 includes a first current interrupting element 71 and a second current interrupting element 72, which are current interrupting elements. The first current interrupting element 71 is provided in the first branch wiring 61. The first current interrupting element 71 is a diode. The anode terminal of the first current interrupting element 71 is electrically connected to the ground terminal 27. The cathode terminal of the first current interrupting element 71 is electrically connected to the first negative wiring 31. The first current interrupting element 71 allows current to flow from the ground terminal 27 through the first branch wiring 61 toward the first negative wiring 31. On the other hand, the first current interrupting element 71 interrupts current flowing from the first negative wiring 31 through the first branch wiring 61 toward a branch point 63 of the first branch wiring 61 to the ground terminal 27.

The second current interrupting element 72 is provided in the second branch wiring 62. The second current interrupting element 72 is a diode. The anode terminal of the second current interrupting element 72 is electrically connected to the ground terminal 27. The cathode terminal of the second current interrupting element 72 is electrically connected to the second negative wiring 32. The second current interrupting element 72 allows current to flow from the ground terminal 27 through the second branch wiring 62 toward the second negative wiring 32. On the other hand, the second current interrupting element 72 interrupts current flowing from the second negative wiring 32 through the second branch wiring 62 toward the branch point 63 of the second branch wiring 62 to the ground terminal 27. Therefore, a current interrupting element is provided in each branch wiring and interrupts current flowing from each negative wiring through each branch wiring toward the branch point 63 of the branch wiring to the ground terminal 27. Note that the "branch point 63" is the branch point of the first branch wiring 61 relative to the ground terminal 27, and is also the branch point of the second branch wiring 62 relative to the ground terminal 27.

[Operation of the First Embodiment]
Next, the operation of the first embodiment will be described.
In a solenoid valve drive control device 20 having only one control circuit 21, the control circuit 21 generally has only one ground terminal 27. In this case, in order to reduce the number of wires drawn out from the solenoid valve drive control device 20, it is necessary to electrically connect the ground terminal 27 to each of the first negative electrode wiring 31 and the second negative electrode wiring 32. For this reason, the solenoid valve drive control device 20 needs to be configured to include a first branch wiring 61 and a second branch wiring 62.

Now, consider a case where the second branch wiring 62 does not have a second current interruption element 72. In this case, even if the second negative terminal 18 of the external control device 15 is in the OFF state, current will flow in a circular fashion, as shown by the dashed arrow in Figure 2. Specifically, current will flow from the positive terminal 16 of the external control device 15 through the common positive wiring 30, the second resistor R2, the second constant voltage circuit 42, the second negative wiring 32, the second branch wiring 62, the first branch wiring 61, the first negative wiring 31, and the first negative terminal 17 in this order.

As a result, even though the second negative terminal 18 is in the OFF state, a drive signal is input to the second signal input terminal 24 via the second connection line 36 and the second signal line 37, turning the second switching element 52 ON. As a result, current is passed through the second drive coil 12, and the first drive coil 11 and second drive coil 12 are simultaneously turned ON, causing the solenoid valve 10 to malfunction.

Also, consider the case where the first branch wiring 61 does not have a first current interruption element 71. In this case, even if the first negative terminal 17 of the external control device 15 is in the OFF state, current will flow in a circular fashion, as shown by the dashed arrow in Figure 3. Specifically, current will flow from the positive terminal 16 of the external control device 15 through the common positive wiring 30, the first resistor R1, the first constant voltage circuit 41, the first negative wiring 31, the first branch wiring 61, the second branch wiring 62, the second negative wiring 32, and the second negative terminal 18 in this order.

As a result, even though the first negative terminal 17 is in the OFF state, a drive signal is input to the first signal input terminal 23 via the first connection line 33 and the first signal line 35, turning the first switching element 51 into the ON state. As a result, current is passed through the first drive coil 11, and the first drive coil 11 and second drive coil 12 are simultaneously turned ON, causing the solenoid valve 10 to malfunction.

Therefore, a first current interrupting element 71 is provided in the first branch wiring 61, and a second current interrupting element 72 is provided in the second branch wiring 62. This configuration prevents current from flowing from the first negative wiring 31 through the first branch wiring 61 toward the branch point 63 of the first branch wiring 61 to the ground terminal 27. Furthermore, the second current interrupting element 72 prevents current from flowing from the second negative wiring 32 through the second branch wiring 62 toward the branch point 63 of the second branch wiring 62 to the ground terminal 27. This prevents electrical continuity between the first negative wiring 31 and the second negative wiring 32 through the first branch wiring 61 and the second branch wiring 62. As a result, the first drive coil 11 and the second drive coil 12 are not simultaneously turned on, preventing malfunction of the solenoid valve 10.

[Effects of the first embodiment]
The first embodiment can provide the following effects.
(1-1) The solenoid valve drive control device 20 employs a common positive wiring 30 that is electrically connected in common to the first ends of the first drive coil 11 and the second drive coil 12 and is also electrically connected to the control circuit 21. For this reason, the number of wirings can be reduced compared to, for example, a case where one positive wiring is provided for each of the first drive coil 11 and the second drive coil 12 and a separate positive wiring is also provided for the control circuit 21.

A first current interrupting element 71 is provided on the first branch wiring 61, and a second current interrupting element 72 is provided on the second branch wiring 62. This prevents the first negative electrode wiring 31 and the second negative electrode wiring 32 from becoming electrically connected via the first branch wiring 61 and the second branch wiring 62. This prevents the first drive coil 11 and the second drive coil 12 from being simultaneously turned on, which could cause the solenoid valve 10 to malfunction. As a result, the number of wires can be reduced, while still allowing the drive control of a solenoid valve 10 having multiple drive coils to be achieved with a single control circuit 21, without causing the solenoid valve 10 to malfunction.

(1-2) The first current interrupting element 71 and the second current interrupting element 72 are diodes. Diodes are suitable as current interrupting elements used to prevent conduction between the first negative electrode wiring 31 and the second negative electrode wiring 32 via the first branch wiring 61 and the second branch wiring 62.

(1-3) When energizing the first drive coil 11 and the second drive coil 12 at different times, the drive of the first drive coil 11 and the second drive coil 12 can be controlled by turning on and off the first switching element 51 and the second switching element 52, respectively. Therefore, even in a configuration that employs a common positive wiring 30, it is possible to reduce the power consumption of each of the first drive coil 11 and the second drive coil 12. This makes it possible to avoid problems such as insufficient starting current to the first drive coil 11 and the second drive coil 12, or a long energization time for the first drive coil 11 and the second drive coil 12.

Second Embodiment
A second embodiment of the solenoid valve drive control device will be described below with reference to Figures 4 to 6. In the embodiment described below, the same components as those in the first embodiment will be denoted by the same reference numerals, and redundant explanations will be omitted or simplified. In the second embodiment, the configuration of the current interruption element differs from that of the first embodiment.

<First current interrupting element 81 and second current interrupting element 82>
As shown in FIG. 4 , the solenoid valve drive control device 20 includes a first current interrupting element 81 and a second current interrupting element 82, which are current interrupting elements. The first current interrupting element 81 is provided in the first branch wiring 61. The first current interrupting element 81 is a switching element. Specifically, the first current interrupting element 81 is an n-channel MOSFET (metal-oxide-semiconductor field-effect transistor). A gate terminal of the first current interrupting element 81 is electrically connected to the first signal line 35. A drain terminal of the first current interrupting element 81 is electrically connected to a branch point 63 of the first branch wiring 61 relative to the ground terminal 27. A source terminal of the first current interrupting element 81 is connected to the first negative wiring 31.

The first current interrupting element 81 is turned on when a signal from the first signal line 35 is input to the gate terminal. The first current interrupting element 81 is turned off when no signal from the first signal line 35 is input to the gate terminal. Therefore, when the first negative terminal 17 of the external control device 15 is turned on, the first current interrupting element 81 is turned on. When the first current interrupting element 81 is turned on, it allows current to flow from the ground terminal 27 through the first branch wiring 61 toward the first negative wiring 31. On the other hand, when the first current interrupting element 81 is turned off, it interrupts current to flow from the first negative wiring 31 through the first branch wiring 61 toward the branch point 63 of the first branch wiring 61 to the ground terminal 27.

The second current blocking element 82 is provided in the second branch wiring 62. The second current blocking element 82 is a switching element. Specifically, the second current blocking element 82 is an n-channel MOSFET (metal-oxide-semiconductor field-effect transistor). The gate terminal of the second current blocking element 82 is electrically connected to the second signal line 37. The drain terminal of the second current blocking element 82 is electrically connected to the branch point 63 of the second branch wiring 62 relative to the ground terminal 27. The source terminal of the second current blocking element 82 is connected to the second negative wiring 32.

The second current interrupting element 82 is turned on when a signal from the second signal line 37 is input to the gate terminal. The second current interrupting element 82 is turned off when no signal from the second signal line 37 is input to the gate terminal. Therefore, when the second negative terminal 18 of the external control device 15 is turned on, the second current interrupting element 82 is turned on. When the second current interrupting element 82 is turned on, it allows current to flow from the ground terminal 27 through the second branch wiring 62 toward the second negative wiring 32. On the other hand, when the second current interrupting element 82 is turned off, it interrupts current to flow from the second negative wiring 32 through the second branch wiring 62 toward the branch point 63 of the second branch wiring 62 to the ground terminal 27.

[Operation of the second embodiment]
Next, the operation of the second embodiment will be described.
5 , if the second branch wiring 62 is not provided with the second current interruption element 82, for example, a current will flow in a loop even when the second negative electrode terminal 18 of the external control device 15 is in an OFF state. Specifically, a current will flow from the positive electrode terminal 16 of the external control device 15 through the common positive electrode wiring 30, the second resistor R2, the second constant voltage circuit 42, the second negative electrode wiring 32, the second branch wiring 62, the first branch wiring 61, the first negative electrode wiring 31, and the first negative electrode terminal 17 in this order.

As a result, even though the second negative terminal 18 is in the OFF state, a drive signal is input to the second signal input terminal 24 via the second connection line 36 and the second signal line 37, turning the second switching element 52 ON. As a result, current is passed through the second drive coil 12, and the first drive coil 11 and second drive coil 12 are simultaneously turned ON, causing the solenoid valve 10 to malfunction.

As shown by the dashed arrow in Figure 6, if the first branch wiring 61 does not have a first current interruption element 81, current will flow in a circular fashion even when the first negative terminal 17 of the external control device 15 is in the OFF state. Specifically, current will flow from the positive terminal 16 of the external control device 15 through the common positive wiring 30, the first resistor R1, the first constant voltage circuit 41, the first negative wiring 31, the first branch wiring 61, the second branch wiring 62, the second negative wiring 32, and the second negative terminal 18 in this order.

As a result, even though the first negative terminal 17 is in the OFF state, a drive signal is input to the first signal input terminal 23 via the first connection line 33 and the first signal line 35, turning the first switching element 51 into the ON state. As a result, current is passed through the first drive coil 11, and the first drive coil 11 and second drive coil 12 are simultaneously turned ON, causing the solenoid valve 10 to malfunction.

Therefore, a first current interrupting element 81 is provided on the first branch wiring 61, and a second current interrupting element 82 is provided on the second branch wiring 62. Accordingly, for example, when the first negative electrode terminal 17 is in the OFF state, the first current interrupting element 81 is turned OFF. As a result, the first current interrupting element 81 interrupts the current flowing from the first negative electrode wiring 31 through the first branch wiring 61 toward the branch point 63 of the first branch wiring 61 to the ground terminal 27. Furthermore, for example, when the second negative electrode terminal 18 is in the OFF state, the second current interrupting element 82 is turned OFF. As a result, the second current interrupting element 82 interrupts the current flowing from the second negative electrode wiring 32 through the second branch wiring 62 toward the branch point 63 of the second branch wiring 62 to the ground terminal 27. Therefore, electrical continuity between the first negative electrode wiring 31 and the second negative electrode wiring 32 is prevented via the first branch wiring 61 and the second branch wiring 62. As a result, the first drive coil 11 and the second drive coil 12 will not be simultaneously turned on, which would cause the solenoid valve 10 to malfunction.

[Effects of the second embodiment]
In the second embodiment, in addition to the effects (1-1) and (1-3) of the first embodiment, the following effects can be obtained.

(2-1) The first current interruption element 81 and the second current interruption element 82 are switching elements. Switching elements are suitable as current interruption elements used to prevent conduction between the first negative electrode wiring 31 and the second negative electrode wiring 32 via the first branch wiring 61 and the second branch wiring 62.

[Example of change]
The above-described embodiments can be modified as follows: The above-described embodiments and the following modifications can be combined with each other within the scope of technical compatibility.

- In each of the above embodiments, the solenoid valve 10 may have three or more drive coils. In this case, it is sufficient that one negative electrode wire is provided for each drive coil. One switching element is also provided for each drive coil. Furthermore, one branch wire is provided for each negative electrode wire. A current interruption element is provided for each branch wire.

- In each of the above embodiments, the first switching element 51 and the second switching element 52 are not limited to n-channel MOSFETs (MOS field effect transistors).

In the above-described embodiments, the configurations of the first constant voltage circuit 41 and the second constant voltage circuit 42 are not particularly limited.
In the second embodiment, the switching elements, which are the first current blocking element 81 and the second current blocking element 82, are not limited to n-type channel MOSFETs (MOS field effect transistors).

10... solenoid valve, 11... first drive coil which is a drive coil, 12... second drive coil which is a drive coil, 20... solenoid valve drive control device, 21... control circuit, 27... ground terminal, 30... common positive wiring, 31... first negative wiring which is a negative wiring, 32... second negative wiring which is a negative wiring, 41... first constant voltage circuit which is a constant voltage circuit, 42... second constant voltage circuit which is a constant voltage circuit, 51... first switching element which is a switching element, 52... second switching element which is a switching element, 61... first branch wiring which is a branch wiring, 62... second branch wiring which is a branch wiring, 63... branch point, 71, 81... first current interruption element which is a current interruption element, 72, 82... second current interruption element which is a current interruption element.

Claims (3)

A solenoid valve drive control device that controls the drive of a solenoid valve having a plurality of drive coils,
a control circuit that controls the energization of the plurality of drive coils and has only one ground terminal;
a plurality of switching elements each provided corresponding to the plurality of drive coils, and each controlling on/off of current supply to the drive coils;
a common positive wiring electrically connected in common to first ends of the plurality of drive coils and also electrically connected to the control circuit;
a plurality of negative electrode wirings provided one for each of the plurality of drive coils and electrically connected to second ends of the plurality of drive coils;
a plurality of constant voltage circuits provided one for each of the plurality of negative wirings and provided between the common positive wiring and each of the negative wirings to apply a constant voltage from the common positive wiring to the control circuit;
a plurality of branch wirings, each of which is provided corresponding to the plurality of negative electrode wirings, electrically connected to the ground terminal, branching from the ground terminal and electrically connected to the plurality of negative electrode wirings, respectively;
a current interruption element that is provided in each of the branch wirings and that interrupts current flowing from each of the negative wirings through each of the branch wirings toward a branch point in the branch wiring that corresponds to the ground terminal. The solenoid valve drive control device according to claim 1, wherein the current interruption element is a diode. The solenoid valve drive control device according to claim 1, wherein the current interruption element is a switching element.