JP3121269B2 - Solenoid valve drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve driving circuit in which a solenoid valve is driven by a high side switch element.

[0002]

2. Description of the Related Art When a solenoid valve is driven, a drive circuit connects a semiconductor switching element or the like in series with the solenoid valve, and controls the semiconductor switching element to be turned on and off by an external control signal. In general, the configuration is such that the exciting current to the motor is controlled. Such a switching element is usually arranged on the low side of the solenoid valve in many cases. However, when driving a solenoid valve used in an automobile or the like, there is an increasing demand for driving the solenoid valve with a high-side switch from the viewpoint of safety. The reason is that in automobiles, etc., the body is connected to the negative terminal of the battery, so even if the drive line short-circuits with the body, a system in which a solenoid valve is placed on the ground side as seen from the switch (high-side switch system) This is because the solenoid valve is safe because it is not accidentally energized.

A configuration in which an electromagnetic valve is arranged on the ground side and this electromagnetic valve is driven by a high-side switch,
For example, it is disclosed in JP-A-6-26589.
As shown in FIG. 18, the solenoid valve drive circuit disclosed here is a switching element for boosting the DC voltage of the DC power supply 1 by the booster circuit 6 and pulling up the boosted DC voltage. It is configured to apply and supply a pull-up voltage to a solenoid valve 5 via a transistor 2. The booster circuit 6 includes a reactor 7, a diode 8, a capacitor 9, and a chopper NPN transistor 10.
It consists of. A circuit for driving the solenoid valve 5 at a constant current is composed of the transistor 3, the resistor 4, and the backflow preventing diode 11.

The operation of this circuit is as follows. When the transistors 2 and 3 are turned on, the voltage boosted by the booster circuit 6 and charged in the capacitor 9 is applied to the solenoid valve 5 via the transistor 2. Therefore, the solenoid valve 5
, A current large enough for driving flows, and the strong electromagnetic force generated by this causes the solenoid valve 5 to operate quickly.
When the transistor 2 is turned off, the holding current limited by the resistor 4 flows to the solenoid valve 5 via the transistor 3. Thus, the solenoid valve 5 is kept held for a certain period by the electromagnetic force generated by the holding current. Thereafter, when the transistor 3 is turned off, the power supply to the solenoid valve 5 is cut off and the solenoid valve 5 is opened.

[0005]

When such a high-side switch is formed by an NPN transistor, the driving circuit has a structure as shown in FIG. Here, PNP is used for driving the transistor 2.
Another type of transistor 12 is used. In general,
V _CE1 of the transistor 2 that directly turns on and off the current flowing through the solenoid valve 5 is larger than V _CE2 of the preceding transistor 12. For example, V _CE2 of transistor 12 is about 0.3 V, while V _CE1 of transistor 2 is about 2.
It is about 3V. This is a value obtained by adding V _CE2 of the transistor 12 and V _{BE of the} transistor 2. Therefore, if the current to the solenoid valve 5 is 2 A, the power consumption of the transistor 2 is 4.6 W, which is not preferable in terms of wasteful power consumption and heat generation. Further, there arises a disadvantage that the minimum operating voltage of the solenoid valve also increases by 2.3 V. As a high side switch,
In addition, an N-channel type field effect transistor (FE)
The use of T) is also conceivable, but produces the same problem. Therefore, in order to efficiently use an N-channel FET or an NPN transistor as a high-side switch element, it is necessary to generate a voltage higher than the solenoid valve drive voltage.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned disadvantages in the prior art by enabling efficient on / off control of a high side switch for driving an electromagnetic valve at a high voltage. An object of the present invention is to provide a solenoid valve driving device.

[0007]

According to a first aspect of the present invention, there is provided an electromagnetic valve driving apparatus for driving an electromagnetic valve, comprising: a DC power supply; and a power supply from the DC power supply. A booster circuit for boosting the output voltage of the DC power supply to obtain a high voltage; and a semiconductor switching element for controlling application of the high voltage to the solenoid coil of the solenoid valve, which is provided on the high side of the solenoid valve. And a capacitor, and the DC power supply and the booster circuit charge the capacitor with a control high voltage for ON / OFF control of the semiconductor switching element. Voltage accumulating circuit for applying the control high voltage to the control electrode of the semiconductor switching element at a required timing. Lies in that a switching circuit.

According to this configuration, when the power supply of the device is turned on, a charging current flows from the DC power supply and the booster circuit to the capacitor. When the charging current of the capacitor becomes substantially equal to the voltage of the DC power supply, the charging current does not flow from the DC power supply to the capacitor, and the charging current to the capacitor is only from the booster circuit. In this way, the capacitor is charged to the level of the high voltage. Thereafter, when the switching circuit operates at a desired timing, the high voltage for control stored in the capacitor is applied to the control electrode of the semiconductor switching element, and the semiconductor switching element is turned on, and the conduction resistance is reduced by the high voltage for control. It can be very low. As a result, power loss in the semiconductor switching element can be significantly reduced.

According to a second aspect of the present invention, in the first aspect of the present invention, the high-voltage storage circuit is connected in parallel with the capacitor to regulate a charging voltage of the capacitor; It comprises a first charging path provided between a power supply and the capacitor, and a second charging path provided between the output of the booster circuit and the capacitor. According to this configuration, it is possible to reliably prevent the capacitor from being charged with an excessive voltage by the function of the constant voltage diode.

According to a third aspect of the present invention, in the second aspect, a first diode and a first resistor are connected in series between the capacitor and the output of the DC power supply. Wherein the second charging path comprises a second diode and a second resistor connected in series between the capacitor and the output of the booster circuit. According to this circuit configuration, the level of the charging current from the DC power supply and the level of the charging current from the booster circuit can be set independently and easily.

According to a fourth aspect of the present invention, the high voltage storage circuit of the first aspect of the present invention includes a constant voltage diode and includes a constant voltage diode for generating a constant voltage for defining a charging voltage level for the capacitor. A generating circuit, a transistor element having the capacitor connected to the emitter circuit, and the constant voltage being applied to a base, a first charging path provided between a collector of the transistor element and the DC power supply, It comprises a second charging path provided between the collector of the transistor element and the booster circuit.

According to this configuration, the charging current flows to the capacitor through the transistor element, and the constant voltage generation circuit controls only the conduction of the transistor element. Therefore, the current flowing to the constant voltage diode can be reduced, and the constant voltage can be reduced. Power loss and heat generation in the generation circuit can be reduced.

According to a fifth aspect of the present invention, there is provided an electromagnetic valve driving device for driving an electromagnetic valve, comprising: a DC power supply; a power supply from the DC power supply; And an N-channel field effect transistor or NP provided on the high side of the solenoid valve as a semiconductor switching element for controlling the application of the high voltage to the solenoid coil of the solenoid valve.
A high-voltage storage circuit including an N-type transistor and a capacitor, wherein the DC power supply and the booster circuit charge the capacitor with a control high-voltage for on / off control of the semiconductor switching element; A switching circuit for applying a high voltage for control to a control electrode of the semiconductor switching element at a required timing and power supplied from the DC power supply, and after the solenoid valve is driven by the high voltage, the electromagnetic valve A constant current circuit for supplying a constant current to the solenoid coil for maintaining the operation state of the solenoid coil, and applying a high voltage from the booster circuit to the solenoid coil when the semiconductor switching element becomes non-conductive. The capacitor is charged by self-induced energy generated in the solenoid coil when the power supply is shut off. As is the point you.

According to this configuration, when the power supply of the device is turned on, the charging current flows from both the DC power supply and the booster circuit to the capacitor. When the charging current of the capacitor becomes substantially equal to the voltage of the DC power supply, the charging current does not flow from the DC power supply to the capacitor, and the charging current to the capacitor is only from the booster circuit. In this way, the capacitor is charged to the level of the high voltage. Thereafter, when the switching circuit operates at a desired timing, the high voltage for control stored in the capacitor is applied to the control electrode of the semiconductor switching element, and the semiconductor switching element is turned on, and the conduction resistance is extremely low due to the high voltage. It can be a value. As a result, power loss in the semiconductor switching element can be significantly reduced.

The above operation consumes the high-voltage energy stored in the capacitor. After that, when the application of the high-voltage to the solenoid coil of the solenoid valve is cut off by turning off the semiconductor switching element, the solenoid coil is turned off. Immediately charges the capacitor. Since the subsequent charging by the booster circuit can be performed quickly, the time required for charging the capacitor to a predetermined level is reduced as compared with the first aspect of the present invention in which only the booster circuit and the DC power supply are used for charging. be able to. As a result, even if the ON / OFF cycle of the solenoid valve is shortened, it can be handled.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the high-voltage storage circuit is connected in parallel with the capacitor to regulate a charging voltage of the capacitor; It comprises a first charging path provided between a power supply and the capacitor, and a second charging path provided between the output of the booster circuit and the capacitor. According to this configuration, it is possible to reliably prevent the capacitor from being charged with an excessive voltage by the function of the constant voltage diode.

According to a seventh aspect of the present invention, in the sixth aspect, a first diode and a first resistor are connected in series between the capacitor and the output of the DC power supply. Wherein the second charging path comprises a second diode and a second resistor connected in series between the capacitor and the output of the booster circuit. According to this circuit configuration, the level of the charging current from the DC power supply and the level of the charging current from the booster circuit can be set independently and easily.

An eighth aspect of the present invention is characterized in that the high voltage storage circuit according to the fifth aspect of the present invention includes a constant voltage diode for generating a constant voltage for defining a charging voltage level for the capacitor. A generating circuit, a transistor element having the capacitor connected to the emitter circuit, and the constant voltage being applied to a base, a first charging path provided between a collector of the transistor element and the DC power supply, It comprises a second charging path provided between the collector of the transistor element and the booster circuit.

According to this configuration, the charging current flows to the capacitor through the transistor element, and the constant voltage generation circuit controls only the conduction of the transistor element. Therefore, the current flowing to the constant voltage diode can be reduced, and the constant voltage can be reduced. Power loss and heat generation in the generation circuit can be reduced.

According to a ninth aspect of the present invention, there is provided a solenoid valve driving device for selectively driving a plurality of solenoid valves each of which has a low-side end grounded, comprising: a DC power supply; And a booster circuit for boosting an output voltage of the DC power supply to obtain a high voltage, and a semiconductor switching element for controlling energization of the high voltage to the plurality of solenoid valves and connected to an output of the booster circuit. An N-channel field-effect transistor or an NPN-type transistor; and an output terminal of the semiconductor switching element for selectively supplying the high voltage obtained when the semiconductor switching element is turned on to the plurality of solenoid valves. A selection switch circuit provided between each high-side end of the plurality of solenoid valves, and a control circuit for controlling on / off of the semiconductor switching element A capacitor for charging a high voltage; a power supply path for supplying a charging current from the DC power supply and the booster circuit to one end of the capacitor; and a resistance element connected between the other end of the capacitor and ground. And an application control circuit for applying the control high voltage to the control electrode of the semiconductor switching element at a required timing.

According to this configuration, when the power of the device is turned on, a charging current flows into the capacitor from both the DC power supply and the booster circuit through the power supply path. In this case, since the selection switch circuit does not select any of the solenoid valves, the charging current flowing into the capacitor flows to the ground through the resistance element and returns to the DC power supply and the booster circuit.
Therefore, the value of this resistance element should be set to a value that allows the minimum voltage necessary for driving the switching element to be stored in the capacitor before the first solenoid valve drive is performed after the power is turned on. preferable.

When the charging current of the capacitor becomes substantially equal to the voltage of the DC power supply, the charging current does not flow from the DC power supply to the capacitor, and the charging current to the capacitor is only from the booster circuit. In this way, the capacitor is charged to the level as described above. Thereafter, when the switching circuit operates at a desired timing, the high voltage for control stored in the capacitor is applied to the control electrode of the semiconductor switching element, and the semiconductor switching element is turned on, and the conduction resistance is extremely low due to the high voltage. It can be a value. As a result, power loss in the semiconductor switching element can be reduced. The selection switch circuit operates in synchronization with the on / off of the semiconductor switching element, selectively connects the solenoid coil of the solenoid valve to be driven to the semiconductor switching element sequentially, and applies a high voltage to a plurality of solenoid valves in a required order. It can be applied sequentially.

According to a tenth aspect of the present invention, in the ninth aspect of the present invention, a constant voltage diode is provided in parallel with the capacitor for defining a charging voltage of the capacitor, and the power supply line is connected to the DC power supply. A first charging path provided between the booster circuit and one end of the capacitor; and a first charging path provided between the booster circuit and one end of the capacitor.
And a charging path. According to this configuration,
The function of the constant voltage diode can reliably prevent the capacitor from being charged with an excessive voltage.

According to an eleventh aspect of the present invention, in the tenth aspect of the present invention, a first diode and a first resistor are connected in series between the capacitor and the output of the DC power supply. Wherein a second charging path is connected in series between the capacitor and the output of the booster circuit.
It consists of a diode and a second resistor. According to this circuit configuration, the level of the charging current from the DC power supply and the level of the charging current from the booster circuit can be set independently and easily.

According to a twelfth aspect of the present invention, in the ninth aspect of the present invention, there is provided a constant voltage generating circuit for generating a constant voltage for defining a charging voltage level for the capacitor including a constant voltage diode, and an emitter. A first charging path provided between the collector of the transistor element and the DC power supply, wherein the capacitor includes a transistor element connected to the capacitor and the constant voltage is applied to a base; A second charging path provided between the collector of the transistor element and the booster circuit.

According to this structure, the charging current flows to the capacitor through the transistor element, and the constant voltage generating circuit controls only the conduction of the transistor element. Therefore, the current flowing to the constant voltage diode can be reduced, and the constant voltage can be reduced. Power loss and heat generation in the generation circuit can be reduced.

The feature of the invention of claim 13 is the feature of claim 10
In any one of the twelfth aspects, the zener voltage of the constant voltage diode is higher than the terminal voltage of the DC power supply. According to this configuration, current is not supplied from the DC power supply when charging of the capacitor is completed, so that power saving can be realized. In addition, since the loss due to the constant voltage diode and the resistor is reduced, heat generation there is also reduced, so that an inexpensive element having a small rating can be used.

The features of the invention of claim 14 is the invention of claim 9, the diode resistance element for current due to the counter electromotive force is prevented from flowing to the resistive element generated in the solenoid coil of the solenoid valve The point is that they are connected in series. According to this configuration, it is possible to effectively prevent the negative voltage generated by the back electromotive force generated in the solenoid coil of the solenoid valve from flowing to the resistance element and being suppressed, thereby realizing quick charging of the capacitor. Can be.

According to a fifteenth aspect of the present invention, in a solenoid valve driving device for selectively driving a plurality of solenoid valves each of which has a low-side end grounded, a DC power supply and a power supply from the DC power supply. And a booster circuit for boosting an output voltage of the DC power supply to obtain a high voltage, and a semiconductor switching element for controlling energization of the high voltage to the plurality of solenoid valves and connected to an output of the booster circuit. An N-channel field-effect transistor or an NPN-type transistor; and an output terminal of the semiconductor switching element for selectively supplying the high voltage obtained when the semiconductor switching element is turned on to the plurality of solenoid valves. A selection switch circuit provided between each high-side end of the plurality of solenoid valves, and a control circuit for controlling on / off of the semiconductor switching element; A capacitor for charging a high voltage, a power supply path for supplying a charging current from the DC power supply and the boosting circuit to one end of the capacitor, and controlling the semiconductor switching element at a required timing with the high voltage for control. An application control circuit for applying the voltage to the electrodes, wherein when the power is turned on, the selection switch circuit is operated for a predetermined time to connect the other end of the capacitor to the ground via at least one solenoid coil of the solenoid valve. It is in the point which was made.

According to this configuration, when the power supply is turned on, the selection switch circuit operates for a fixed time and the other end of the capacitor is grounded via at least one solenoid coil. A charging current can flow through the power supply path, the selection switch circuit, and the solenoid coil. When the charging current of the capacitor becomes substantially equal to the voltage of the DC power supply, the charging current does not flow from the DC power supply to the capacitor, and the charging current to the capacitor is only from the booster circuit. In this way, the capacitor is charged to a predetermined level. Therefore, the minimum voltage required for driving the switching element can be stored in the capacitor before the first solenoid valve driving is performed after the power is turned on.

Thereafter, when the switching circuit operates at a desired timing, the high voltage for control stored in the capacitor is applied to the control electrode of the semiconductor switching element to turn on the semiconductor switching element, and the conduction resistance is reduced by the high voltage. It can be very low.
As a result, power loss in the semiconductor switching element can be reduced. The selection switch circuit operates in synchronization with the ON / OFF of the semiconductor switching element, selectively connects the solenoid valves to be driven to the semiconductor switching element sequentially, and sequentially applies a high voltage to a plurality of solenoid valves in a required order. be able to. In the subsequent operations, the capacitor is charged by the voltage generated in the solenoid coil at the timing when the semiconductor switching element is switched from on to off.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing an example of an embodiment of a solenoid valve driving device according to the present invention. The solenoid valve driving device 20 shown in FIG. 1 applies a high voltage to the solenoid coil 21 of the solenoid valve SV in an initial stage of driving, and the solenoid valve SV
This is an electromagnetic valve driving device that performs a constant current drive control for causing a predetermined constant current to flow through the solenoid coil 21 for quickly operating the solenoid valve SV and then maintaining the operation of the electromagnetic valve SV. In FIG. 1, reference numeral 22 denotes a DC power supply for supplying a DC voltage VB, and reference numeral 23 denotes a booster circuit that boosts the DC voltage VB and outputs a high voltage VP of about 160 V. Since the configuration of the booster circuit 23 is the same as that of the booster circuit 6 shown in FIG. 18 , the portions corresponding to the respective portions are denoted by the same reference numerals and description thereof is omitted.

Reference numeral 24 denotes a high voltage VP from the booster circuit 23.
Is an N-channel field effect transistor (FET) provided on the high side opposite to the ground side of the solenoid valve SV as a semiconductor switching element for applying the voltage to the solenoid coil 21 of the solenoid valve SV, and its source is a solenoid. The drain of the coil 21 is connected to the output of the booster circuit 23. In addition,
A series circuit of a constant voltage diode 25 and a diode 26 is connected in parallel to the solenoid coil 21, and the low side terminal of the solenoid coil 21 is directly grounded.

Reference numeral 27 denotes a constant current drive control unit having a known configuration for driving the solenoid valve SV at a constant current. The constant current drive control unit 27 includes the DC power supply 22 and the solenoid valve S
A switching transistor 28, a current detection resistor 29, and a diode 30 which are connected in series as shown in FIG.
The detection voltage generated at both ends of the current detection resistor 29 is input to the constant current circuit 31, and the switching transistor 28 is turned on and off by the constant current circuit 31 so that the solenoid valve SV is driven at a constant current. The control for the constant current driving described above is executed only during a period when the drive control signal DS applied to the control terminal 31A of the constant current circuit 31 is at a high level.

Prior to the constant current drive by the constant current drive control unit 27, the solenoid valve SV is set to the high voltage VP for a predetermined period.
In order to operate at high speed, a switching element drive circuit 32 for outputting a control high voltage VCP for turning on the N-channel field effect transistor 24 for the above-mentioned predetermined period is provided.

FIG. 2 shows a switching element driving circuit 32.
The detailed circuit diagram of FIG. The switching element drive circuit 32 includes a capacitor 41 and charges the capacitor 41 with a control high voltage VCP for controlling ON / OFF of the N-channel type field effect transistor 24 by the DC power supply 22 and the boost circuit 23. And a switching circuit 50 for applying the control high voltage VCP to the gate electrode of the N-channel type field effect transistor 24 at required timing.

First, the high voltage storage circuit 40 will be described. Reference numeral 42 denotes a constant voltage diode connected in parallel with the capacitor 41. The constant voltage diode 42 suppresses the charging voltage of the capacitor 41 to the Zener voltage or less. The diodes 43 and 44 and the resistors 45 and 46
A charging path for flowing a charging current from the DC power supply 22 and the booster circuit 23 to the capacitor 41 is formed.

The switching circuit 50 applies the high voltage VCP between the gate and the source of the N-channel type field effect transistor 24 only while the high voltage control signal HS applied to the control input terminal 50A is at the high level. Switching transistors 51 and 52
And resistors 53 to 56 are connected as shown.

Next, the operation of the high voltage storage circuit 40 will be described with reference to FIGS. Solenoid valve drive 20
Immediately after the power supply is turned on, the charging voltage of the capacitor 41 is zero volts, so that the charging from the DC power supply 22 through the first charging path including the diode 43 and the resistor 46 as shown in FIG. The capacitor 41 is quickly charged by the current IA and the charging current IB from the booster circuit 23 through the second charging path including the diode 44 and the resistors 45 and 46. At this time, the field effect transistor 24 is off. The above-described charging operation is performed by the capacitor 4
The high voltage VCP, which is the charging voltage of No. 1, is a voltage V obtained by subtracting the voltage drop in the diode 43 from the DC voltage VB.
It continues until it becomes B '.

The value of the high voltage VCP is the voltage V obtained by subtracting the voltage drop in the diode 43 from the DC voltage VB.
When the charge reaches B ′, charging from the DC power supply 22 becomes impossible, and only the charging current IB by the booster circuit 23 is provided as shown in FIG. When the value of the high voltage VCP reaches the Zener voltage VZ1 of the constant voltage diode 42,
The current from the booster circuit 23 flows into the constant voltage diode 42, and the charging operation of the DC power supply 22 is completed.

As described above, before driving the solenoid valve SV, the charging current I through the solenoid coil 21 of the solenoid valve SV is controlled.
A and IB flow to the capacitor 41 to charge the capacitor 41. The value of the resistor 46 is appropriately determined so that the solenoid valve SV does not operate when the charging current flows through the solenoid coil 21.

FIG. 5 shows the high voltage VCP as time elapses from when the power supply of the solenoid valve driving device 20 is turned on.
Is shown increasing. As can be seen from the above description, in the range of VCP <VB ′, the charging currents IA and IB flow into the capacitor 41, so that the high voltage VCP
Rapidly rises, but when VCP ≧ VB ′, only the charging current IB is provided, so that the rising rate of the high voltage VCP becomes small, and charging is stopped when VCP = VZ1. Therefore, if VZ1 is set to be larger than VB, the charging current from DC power supply 22 to capacitor 41 does not flow when charging to capacitor 41 is completed, and power saving can be realized. Also,
Since the power loss in the constant voltage diode and the resistor is also reduced, heat generation of the constant voltage diode and the resistor can be suppressed, and the rating can be reduced and an inexpensive element can be used.

Returning to FIG. 2, when the high voltage control signal HS goes high, the switching transistors 51 and 52 of the switching circuit 50 are both turned on, and the high voltage VC
P can be applied between the gate and the source of the field effect transistor 24. The field effect transistor 24 is quickly turned on in response to the control high voltage VCP, and the high voltage VP is applied to the high side terminal of the solenoid coil 21 via the field effect transistor 24. At this time,
Although the potential of the source electrode of the field effect transistor 24 becomes the same as the high voltage VP, the source electrode is connected to the negative terminal of the capacitor 41, so that the potential of the positive terminal of the capacitor 41 becomes the high voltage VP. It becomes equal to the sum of the high voltage VCP and the field effect transistor 24 can be kept on.

In this case, the terminal voltage of the capacitor 41 is 1
If the voltage is 0 V or more, the on-resistance of the field effect transistor 24 can be made sufficiently small, for example, about 0.1Ω. However, solenoid coil 2
If the current flowing through 1 is 2 A, the field effect transistor 2
4 is 2 × 2 × 0.1 = 0.4 (W), which is smaller than 4.6 (W) which is a typical example in the case of the conventional configuration described above.
It can be seen that the power consumption in the above can be reduced to about 1/10. The same is true when an NPN transistor is used instead.

Next, the operation of the solenoid valve driving device 20 shown in FIG. 1 will be described with reference to FIG. In FIG. 6, (A) is a drive input signal S indicating a drive period for driving the solenoid valve SV, (B) is a high-voltage control signal HS, (C)
Is a drive control signal DS. Each of the high-voltage control signal HS and the drive control signal DS is a signal generated by a known means in response to the drive input signal S. In the illustrated example, the high-voltage control signal HS is a time ta from the rise of the drive input signal S. Pulse width. The drive control signal DS is a pulse signal that falls at the same time as the falling drive input signal S falls after the time tb has elapsed from the fall of the high voltage control signal HS.

As already described in detail, the high voltage control signal HS
Is applied to the switching element drive circuit 32 at T = T1, whereby the control high voltage VCP is applied between the gate and the source of the field effect transistor 24, and the high voltage VP from the boost circuit 23 is applied to the solenoid valve SV. The voltage is applied to the solenoid coil 21 as the solenoid valve applied voltage VS.
FIG. 6D shows how the level of the solenoid valve applied voltage VS changes, and FIG. 6E shows how the level of the solenoid valve current IS flowing through the solenoid coil 21 changes.

Immediately after the high voltage VP is applied to the solenoid coil 21 at T1, the solenoid valve applied voltage V
The level of S rapidly increases, but the level gradually decreases as electric charges are discharged from the capacitor 9. on the other hand,
The level of the solenoid valve current IS gradually increases over time due to its inductance. in this way,
At T = T1, the high voltage VP is applied to the solenoid coil 21.
, The solenoid valve SV is operated at high speed, and can quickly enter a predetermined operating state.

When the high voltage control signal HS changes to low level at T = T2, the field effect transistor 24 is turned off. As a result, a back electromotive force is generated in the solenoid coil 21 and the voltage VS applied to the solenoid valve becomes a negative value. Here, the reason why the level of the solenoid valve applied voltage VS has a substantially constant negative value until T3 when the drive control signal DS rises is due to the function of the constant voltage diode 25, and this value is, for example, You can choose -60V. At T1 <T <T2, the level of the solenoid valve current IS drops sharply. However, the solenoid valve SV is kept in a predetermined operation state.

When the drive control signal DS goes high at T = T3, the constant current drive control section 27 starts operating, and the solenoid valve SV enters a constant current drive state. The constant current drive is performed by controlling the switching transistor 28 to be on and off by the constant current circuit 31 so that the current flowing through the current detection resistor 29 has a constant value. Since the flywheel circuit (not shown) is built in the constant current circuit 31, a large negative voltage is not generated at both ends of the solenoid coil 21 even when the switching transistor 28 is turned off. The valve current IS is also maintained at a substantially constant value.

When the drive of the solenoid valve SV ends at T = T4, the operation of the constant current circuit 31 is prohibited at the falling timing of the drive control signal DS, and the flywheel circuit also does not operate. Means that a large negative voltage is generated. This is T = T2
For the same reason that a negative voltage occurs. Then, the solenoid valve current IS decreases rapidly and becomes zero.

Next, the charging operation of the capacitor 41 of the switching element drive circuit 32 will be described with reference to FIGS. The control high voltage VCP charged in the capacitor 41 is used to keep the field effect transistor 24 on during T1 <T <T2, thereby discharging electric charge and preventing the level of the control high voltage VCP from lowering. Bring. The charging operation of the capacitor 41 is performed as follows during a period when the drive input signal S is at a high level. During the period from T1 to T2, the charge of the capacitor 41 flows out, and as shown in FIG. 8C, during this period, the level of the control high voltage VCP decreases with the passage of time. Then, at T2, the solenoid coil 2
1 generates a large negative voltage, and the negative high voltage causes the negative terminal of the constant voltage diode 42 to have a large negative potential.
The same effect as when the voltage of the DC power supply 22 and the voltage of the booster circuit 23 are increased is produced, and large charging currents IA and IB flow through the capacitor 41, so that the capacitor 41 can be charged quickly. Therefore, immediately after T2, the control high voltage V
The charge of the capacitor 41 can be substantially completed when the level of the CP sharply increases and enters the constant current driving.

As described above, the electric charge of the capacitor 41 discharged by one drive of the solenoid valve SV is charged again during the drive of the solenoid valve SV, so that the next drive of the solenoid valve is required immediately. Also in the field effect transistor 24
Can be reliably turned on as scheduled.

According to this configuration, the power loss in the field-effect transistor caused by switching the voltage application to the solenoid coil 21 by the N-channel field-effect transistor 24 can be extremely reduced. Further, it is easy to secure the minimum operating voltage. That is, the voltage drop in the field-effect transistor
Since the voltage can be suppressed to about × 2A = 0.2 V, the minimum operating power supply voltage can be reduced.

When the solenoid valve driving is started, the capacitor 41 can be charged in a short time by utilizing the back electromotive force generated in the solenoid coil 21 of the solenoid valve SV. As a result, the driving cycle can be shortened. In addition, even before the solenoid valve is driven, the capacitor 41 can be charged to a voltage higher than the power supply voltage VB in a short time by charging using the DC power supply 22 and the booster circuit 23 in combination.

FIG. 9 shows a modification of the high voltage storage circuit 40 shown in FIG. The high voltage storage circuit 40A shown in FIG. 9 has a configuration in which the resistor 46 shown in FIG. 2 is omitted and a resistor 47 is provided in series with the diode 43. According to this configuration, the diode 43 and the resistor 47
And the charging current flowing in the charging path by the diode 44 and the resistor 45 can be adjusted independently and easily.

FIG. 10 shows still another modification of the high voltage storage circuit 40 shown in FIG. In the high-voltage storage circuit 40B shown in FIG. 10, a transistor 48 and a resistor 49 are connected as shown. According to this configuration, since the charging current flows to the capacitor 41 via the transistor 48, the current flowing to the resistor 46 and the constant voltage diode 42 need only flow enough current to generate a predetermined constant voltage to the constant voltage diode 42. Therefore, the value of the resistor 46 can be increased, and the power consumption can be reduced. Also in this configuration, when the charging voltage of the capacitor 41 reaches the Zener voltage of the constant voltage diode 42, the resistor 49 and the transistor 48
The charging operation via is stopped.

FIG. 11 shows another embodiment of the solenoid valve driving device according to the present invention. An electromagnetic valve driving device 60 shown in FIG. 11 includes a plurality of electromagnetic valves SV1 and SV2.
Are driven by a first drive input signal S1 and a second drive input signal S2 which do not overlap with each other. Solenoid valve SV by solenoid valve driving device 60
1 and SV2 are driven by the solenoid valve driving device 20 shown in FIG.
, The solenoid valve driving device 60 has a selection switch circuit 61 for selecting the solenoid valve to be driven, and the first and second drive input signals SV1,
Only in that a signal generation circuit 62 for generating first and second selection control signals SL1 and SL2 for controlling the high voltage control signal HS, the drive control signal DS and the selection switch circuit 61 in response to SV2 is provided. It is different from the valve driving device 20. Therefore, in each part of FIG. 11, the same parts as those of FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

The selection switch circuit 61 comprises thyristors 63 and 64 provided corresponding to the first and second drive input signals SV1 and SV2, and their trigger input terminals 63
A, 64A to the first and second selection control signals SL1, SL2
Are respectively added. In the present embodiment, the thyristors corresponding to the rising edges of the first and second selection control signals SL1 and SL2 are turned on, and the thyristors are kept on during the high level period. Note that the first and second selection control signals SL1 and SL2 obtained by the signal generation circuit 62 are the first and second selection control signals, respectively.
And the second drive input signals S1 and S2, and the high voltage control signal HS and the drive control signal DS are obtained corresponding to the first and second drive input signals S1 and S2, respectively.

FIG. 12 shows the switching element driving circuit 3
A detailed circuit diagram of 2 'is shown. The switching element drive circuit 32 'is basically the same as the switching element drive circuit 32 shown in FIG. 2 except that the charging of the capacitor 41 immediately after power-on is performed by the first and second solenoid valves SV.
1, unlike the switching element drive circuit 32 only in that a resistor RB is provided between the negative terminal of the capacitor 41 and the ground so that the current can flow without passing through the solenoid coils 211 and 212 of the SV2. There is only. Therefore, the same reference numerals are given to the portions corresponding to the respective portions in FIG. 2 among the respective portions in FIG. 12, and the description thereof will be omitted.

Next, the operation of the solenoid valve driving device 60 shown in FIG. 11 will be described with reference to FIG. T = TA
When the power supply of the solenoid valve driving device 60 is turned on, charging of the capacitor 41 is performed via the resistor RB.
This will be described with reference to FIGS. 14 and 15. Immediately after the power is turned on, neither the first nor the second drive input signal S1 or S2 is output, and both the thyristors 63 and 64 are turned off. ing. In this state, the DC voltage VB and the high voltage VP are applied to the high voltage storage circuit 40 ', and the charging currents I1 and I2 due to these voltages are applied to the capacitor 4
The current flowing to 1 and passing through the capacitor 41 will flow to ground via the resistor RB. In this way, when the control high voltage VCP, which is the terminal voltage of the capacitor 41, rises to the voltage VB 'obtained by subtracting the voltage drop in the diode 43 from the DC voltage VB, the charging current I1 from the DC power supply 22 flows to the capacitor 41. And only the charging current I2 from the booster circuit 23 is obtained (FIG. 15). In this way, the capacitor 41 is charged to the predetermined high voltage VCP for control (FIG. 13 (K)).

When the level of the first drive input signal S1 rises at T = TB, a first selection control signal SL1 is output, thereby turning on the thyristor 63 (FIG. 13).
(A), (E)). In response to the input of the first drive input signal S1, the drive control signal DS and the high voltage control signal HS are output correspondingly in the same manner as shown and described in FIG. As a result, similarly to the case of the solenoid valve driving device 20, first, the period control high voltage VCP for TB to TC is used.
As a result, the field effect transistor 24 is turned on, the first solenoid valve SV1 operates at high speed, and the constant current drive is performed during the period from TD to TE. In this case, also in this case, the capacitor 41 is quickly charged by the back electromotive force generated in the solenoid coil 211 in TC (FIG. 13).
(K)). When the second drive input signal S2 is output at T = TF, the second solenoid valve SV2 is driven in exactly the same manner.

As described above, the solenoid valve driving device 60 is characterized in that the capacitor 41 is charged via the resistor RB immediately after the power is turned on.
Therefore, the value of the resistor RB is changed by the time the first solenoid valve is driven after the power is turned on.
It is necessary to set the value to a value that can be charged to a voltage that can perform required driving for No. 4 without any trouble.

As shown in FIG. 16, by connecting a diode DA in series with a resistor RB as shown in FIG. 16, when a large negative voltage is generated in the solenoid coil 211 at TC and TE, this negative voltage Can be prevented from flowing through the resistor RB, and poor charging of the capacitor 41 can be effectively prevented.
Required charging can be performed promptly.

In the solenoid valve driving device 60 shown in FIGS. 11 and 12, the resistor RB is provided so as to enable charging of the capacitor 41 immediately after the power is turned on. Later, one of the thyristors 62 and 63 is forcibly turned on for a certain time,
Thus, a configuration in which the capacitor 41 can be charged may be employed.

FIG. 17 shows a main part of a modified example of the solenoid valve driving device 60 configured as described above. In FIG. 17, reference numeral 71 denotes a power-on detection circuit for detecting power-on, and reference numeral 72 denotes a monostable circuit. The power-on detection circuit 71 detects the power-on, activates the monostable circuit 72, outputs a pulse PO of a fixed time duration, and applies this pulse PO to the trigger input terminal 63A of the thyristor 63, thereby immediately after the power-on. The negative terminal of the capacitor 41 is grounded via the solenoid coil 211 for a certain period of time. Thereby, the solenoid coil 21 and the DC power supply 2
2 allows the capacitor 41 to be initially charged.

The high voltage storage circuit 4 shown in FIG.
For 0 ', the same effects can be obtained by applying the circuits shown in FIGS. 3 and 4 in the same manner.

[0068]

According to the first aspect of the present invention, when the voltage application to the solenoid coil of the solenoid valve is switched by using a semiconductor switching element of an N-channel type field effect transistor or an NPN type transistor, the semiconductor switching element Power loss can be extremely reduced. Further, it is easy to secure the minimum operating voltage. Further, when the solenoid valve is started, the capacitor can be charged in a short time by using the back electromotive force generated in the solenoid coil of the solenoid valve. As a result, the drive cycle of the solenoid valve can be shortened. In addition, even before the solenoid valve is driven, the capacitor can be charged to a voltage higher than the power supply voltage in a short time by charging using the DC power supply and the booster circuit together, so that a high control voltage can be applied to the semiconductor switching element, and the operation of the solenoid valve can be performed. Can be improved.

According to the second aspect of the present invention, it is possible to reliably prevent the capacitor from being charged with an excessive voltage by the function of the constant voltage diode.

According to the third aspect of the present invention, the level of the charging current from the DC power supply and the level of the charging current from the boosting circuit can be set independently and easily.

According to the fourth aspect of the present invention, the charging current flows to the capacitor through the transistor element, and the constant voltage generating circuit controls only the conduction of the transistor element, so that the current flowing to the constant voltage diode can be reduced. Thus, power loss and heat generation in the constant voltage generation circuit can be reduced.

According to the fifth aspect of the present invention, even if the high-voltage energy stored in the capacitor is consumed, the application of the high-voltage to the solenoid coil of the solenoid valve is cut off by turning off the semiconductor switching element. The capacitor is immediately charged by the back electromotive force generated in the solenoid coil when the power is turned off. Since the subsequent charging by the booster circuit can be performed quickly, the time required for charging the capacitor to a predetermined level is reduced as compared with the first aspect of the present invention in which only the booster circuit and the DC power supply are used for charging. be able to. As a result, even if the ON / OFF cycle of the solenoid valve is shortened, it can be handled.

According to the sixth aspect of the present invention, it is possible to reliably prevent the capacitor from being charged with an excessive voltage by the function of the constant voltage diode.

According to the seventh aspect of the present invention, the level of the charging current from the DC power supply and the level of the charging current from the booster circuit can be set independently and easily.

According to the eighth aspect of the present invention, the charging current flows to the capacitor through the transistor element, and the constant voltage generating circuit controls only the conduction of the transistor element, so that the current flowing to the constant voltage diode can be reduced. Thus, power loss and heat generation in the constant voltage generation circuit can be reduced.

According to the ninth aspect of the present invention, even in a configuration in which a plurality of solenoid valves are sequentially selected and driven, the resistance element connected between the other end of the capacitor and the ground allows the power to be turned on when the power is turned on. A charging current can flow from both the DC power supply and the booster circuit through the power supply path to the capacitor.

According to the tenth aspect, the function of the constant voltage diode can reliably prevent the capacitor from being charged with an excessive voltage.

According to the eleventh aspect, the level of the charging current from the DC power supply and the level of the charging current from the boosting circuit can be set independently and easily.

According to the twelfth aspect of the present invention, the charging current flows to the capacitor through the transistor element, and the constant voltage generating circuit controls only the conduction of the transistor element. Therefore, the current flowing to the constant voltage diode can be reduced. Thus, power loss and heat generation in the constant voltage generation circuit can be reduced.

According to the thirteenth aspect, no current is supplied from the DC power supply when charging of the capacitor is completed, so that power saving can be realized. In addition, since the loss due to the constant voltage diode and the resistor is reduced, heat generation there is also reduced, so that an inexpensive element having a small rating can be used.

According to the fourteenth aspect of the present invention, it is possible to effectively prevent the negative voltage generated by the back electromotive force generated in the solenoid coil of the solenoid valve from flowing to the resistance element and being suppressed, and to promptly supply the capacitor to the capacitor. Charging can be realized.

According to the fifteenth aspect of the present invention, when the power is turned on, the selection switch circuit operates for a predetermined time and the other end of the capacitor is grounded via at least one solenoid coil. Charging current can flow from both circuits through the feed line, selection switch circuit, and solenoid coil.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an example of an embodiment of a solenoid valve driving device according to the present invention.

FIG. 2 is a detailed circuit diagram of the switching element drive circuit shown in FIG.

FIG. 3 is an explanatory diagram for explaining a capacitor charging operation immediately after turning on the power supply of the high voltage storage circuit shown in FIG. 2;

FIG. 4 is an explanatory diagram for explaining a capacitor charging operation of the high-voltage voltage storage circuit shown in FIG. 2 immediately after power is turned on.

FIG. 5 is an explanatory diagram for explaining a capacitor charging operation immediately after power-on of the high-voltage storage circuit shown in FIG. 2;

FIG. 6 is a waveform chart of signals of respective parts for explaining the operation of the solenoid valve driving device shown in FIG. 1;

FIG. 7 is an explanatory diagram for explaining a capacitor charging operation of the high-voltage storage circuit shown in FIG. 2 during the operation of the solenoid valve.

FIG. 8 is a waveform chart of signals of respective parts for describing a capacitor charging operation of the high voltage storage circuit shown in FIG. 2 during a solenoid valve operation period.

FIG. 9 is a circuit diagram showing a modification of the high-voltage storage circuit shown in FIG. 2;

FIG. 10 is a circuit diagram showing another modified example of the high voltage storage circuit shown in FIG. 2;

FIG. 11 is a circuit diagram showing an example of another embodiment of the solenoid valve driving device according to the present invention.

12 is a detailed circuit diagram of the switching element driving circuit shown in FIG.

FIG. 13 is a waveform chart of signals of respective parts for explaining the operation of the solenoid valve driving device shown in FIG. 11;

14 is an explanatory diagram for explaining a capacitor charging operation immediately after power-on of the high voltage storage circuit shown in FIG. 12;

FIG. 15 is an explanatory diagram for explaining a capacitor charging operation immediately after power-on of the high-voltage storage circuit shown in FIG. 12;

FIG. 16 is a main part circuit diagram of a modification of the high voltage storage circuit shown in FIG. 12;

FIG. 17 is a main part circuit diagram of a modified example of the solenoid valve driving device shown in FIG. 11;

FIG. 18 is a circuit diagram showing an example of a conventional solenoid valve driving device.

19 is a detailed circuit diagram of a drive circuit of the solenoid valve drive device shown in FIG.

[Explanation of symbols]

 20, 60 Solenoid valve driving device 21 Solenoid coil 22 DC power supply 23 Boost circuit 24 Field effect transistor 25 Constant voltage diode 26 Diode 27 Current drive control unit 32, 32 'Switching element drive circuit 41 Capacitor 40, 40A, 40B High voltage voltage storage circuit 42 constant voltage diode 43, 44 diode 45, 46 resistor 50 switching circuit 61 selection switch 62 signal generation circuit DS drive control signal IA, IB charging current VZ1 Zener voltage HS high voltage control signal S drive input signal S1 first drive input signal S2 Second drive input signal SV, SV1, SV2 Solenoid valve SL1 First selection control signal SL2 Second selection control signal VB DC voltage VP High voltage VCP High voltage for control

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-6-26589 (JP, A) JP-A-63-34387 (JP, A) JP-A-6-323461 (JP, A) JP-A-7-343 71639 (JP, A) JP-A-4-102776 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16K 31/06 310 H01F 7/18

Claims (15)

(57) [Claims] An electromagnetic valve driving device for driving an electromagnetic valve, comprising: a DC power supply; a booster circuit that receives power supplied from the DC power supply and boosts an output voltage of the DC power supply to obtain a high voltage; An N-channel field effect transistor or an NPN transistor provided on a high side of the solenoid valve as a semiconductor switching element for controlling application of a high voltage to a solenoid coil of the solenoid valve; A high-voltage storage circuit for charging the capacitor with a control high voltage for controlling on / off of the semiconductor switching element by the power supply and the booster circuit; and applying the control high voltage to the semiconductor at a required timing. And a switching circuit for applying a voltage to a control electrode of the switching element. 2. A first constant voltage diode connected between the DC power supply and the capacitor, wherein the high voltage storage circuit is connected in parallel with the capacitor and regulates a charging voltage of the capacitor. The solenoid valve driving device according to claim 1, further comprising a charging path, and a second charging path provided between an output of the booster circuit and the capacitor. 3. The first charging path includes a first diode and a first resistor connected in series between the capacitor and an output of the DC power supply, and the second charging path includes the capacitor. 3. The solenoid valve driving device according to claim 2, further comprising a second diode and a second resistor connected in series between the second diode and an output of the booster circuit. 4. A constant voltage generating circuit for generating a constant voltage for defining a charging voltage level for the capacitor, wherein the high voltage storage circuit includes a constant voltage diode, and the capacitor is connected to an emitter circuit. A transistor element to which the constant voltage is applied to a base, a first charging path provided between the collector of the transistor element and the DC power supply, and a transistor connected between the collector of the transistor element and the booster circuit. The solenoid valve driving device according to claim 1, further comprising a second charging path provided. 5. An electromagnetic valve driving device for driving an electromagnetic valve, comprising: a DC power supply; a booster circuit that receives power supplied from the DC power supply and boosts an output voltage of the DC power supply to obtain a high voltage; A DC switching power supply comprising: a N-channel field effect transistor or an NPN transistor provided on a high side of the solenoid valve as a semiconductor switching element for controlling application of a high voltage to a solenoid coil of the solenoid valve; A high voltage storage circuit for charging the capacitor with a control high voltage for controlling the on / off of the semiconductor switching element by the booster circuit; and applying the control high voltage to the semiconductor switching device at a required timing. receiving a switching circuit for applying to the control electrode of the element, the power supply from the DC power supply, the high pressure A constant current circuit for supplying a constant current to the solenoid coil for maintaining the operation state of the solenoid valve after the drive of the solenoid valve by pressure is completed, and the semiconductor switching element is turned off. An electromagnetic valve driving device, wherein the capacitor is charged by self-induced energy generated in the solenoid coil when application of a high voltage from the booster circuit to the solenoid coil is cut off. 6. A first high-voltage storage circuit, comprising: a constant-voltage diode connected in parallel with the capacitor for defining a charging voltage of the capacitor; and a first constant-voltage diode provided between the DC power supply and the capacitor. The solenoid valve driving device according to claim 5, further comprising a charging path, and a second charging path provided between an output of the booster circuit and the capacitor. 7. The first charging path includes a first diode and a first resistor connected in series between the capacitor and an output of the DC power supply, and the second charging path includes the capacitor. 7. The solenoid valve driving device according to claim 6, comprising a second diode and a second resistor connected in series between the output and the output of the booster circuit. 8. A constant voltage generating circuit for generating a constant voltage for defining a charging voltage level for the capacitor, wherein the high voltage storage circuit includes a constant voltage diode, and the capacitor is connected to an emitter circuit. A transistor element to which the constant voltage is applied to a base, a first charging path provided between the collector of the transistor element and the DC power supply, and a transistor connected between the collector of the transistor element and the booster circuit. The electromagnetic valve driving device according to claim 5, further comprising a second charging path provided. 9. An electromagnetic valve driving device for selectively driving a plurality of electromagnetic valves each having a low-side end grounded, comprising: a DC power supply; and an output of the DC power supply receiving power supplied from the DC power supply. A booster circuit for boosting a voltage to obtain a high voltage; and an N-channel field effect transistor or NP connected to an output of the booster circuit as a semiconductor switching element for controlling energization of the high voltage to the plurality of solenoid valves.
An N-type transistor, an output terminal of the semiconductor switching element and each of the plurality of solenoid valves for selectively supplying the high voltage obtained when the semiconductor switching element is turned on to the plurality of solenoid valves. A selection switch circuit provided between the high-side terminal and a capacitor for charging a high voltage for control for ON / OFF control of the semiconductor switching element; the DC power supply and the booster at one end of the capacitor; a feeding path of the order to you supply the charging current from the circuit, and a resistive element connected between the other end and ground of the capacitor, the control electrode of the semiconductor switching element該制patronized high voltage at a predetermined timing And an application control circuit for applying voltage to the solenoid valve. 10. A first constant voltage diode, which is connected in parallel with the capacitor and regulates a charging voltage of the capacitor, wherein the power supply line is provided between the DC power supply and one end of the capacitor. The solenoid valve driving device according to claim 9, further comprising: a charging path, and a second charging path provided between an output of the booster circuit and one end of the capacitor. 11. The first charging path includes a first diode and a first resistor connected in series between the capacitor and an output of the DC power supply, and the second charging path includes the capacitor. And a second resistor and a second resistor connected in series between the output of the booster circuit and a second diode.
0. The electromagnetic valve driving device according to 0. 12. A constant voltage generating circuit including a constant voltage diode for generating a constant voltage for defining a charging voltage level for the capacitor, and the capacitor is connected to an emitter circuit, and the constant voltage is applied to a base. A first charging path provided between the collector of the transistor element and the DC power supply, and a first charging path provided between the collector of the transistor element and the booster circuit. The solenoid valve driving device according to claim 9, further comprising a second charging path provided. 13. The zener voltage of the constant voltage diode is higher than the terminal voltage of the DC power supply.
13. The electromagnetic valve driving device according to 0, 11 or 12. 14. The electromagnetic valve drive according to claim 9 in which the current due to the counter electromotive force is connected a diode for blocking the flow in the resistive element to the resistive element in series generated in the solenoid coil of the solenoid valve apparatus. 15. A solenoid valve driving device for selectively driving a plurality of solenoid valves each having a low-side end grounded, comprising: a DC power supply; and an output of the DC power supply, receiving power supplied from the DC power supply. A booster circuit for boosting a voltage to obtain a high voltage; and an N-channel field effect transistor or NP connected to an output of the booster circuit as a semiconductor switching element for controlling energization of the high voltage to the plurality of solenoid valves.
An N-type transistor, an output terminal of the semiconductor switching element and each of the plurality of solenoid valves for selectively supplying the high voltage obtained when the semiconductor switching element is turned on to the plurality of solenoid valves. A selection switch circuit provided between the high-side end and a capacitor for charging a high voltage for control for ON / OFF control of the semiconductor switching element; the DC power supply and the boost at one end of the capacitor A power supply path for supplying a charging current from a circuit; and an application control circuit for applying the high voltage for control to a control electrode of the semiconductor switching element at a required timing. Operate only for a certain period of time and connect the other end of the capacitor to ground via at least one solenoid coil of the solenoid valve An electromagnetic valve drive device characterized in that: