JP2005344684A - Solenoid valve drive mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solenoid valve drive mechanism enabling a reduction in size by reducing the number of parts without lowering the drive performance of a solenoid valve. <P>SOLUTION: An injector drive device comprises a boosting circuit and a high-tension driving FET. Also, the boosting circuit comprises a boosting capacitor of such a capacity that can supply a valve opening current and a valve holding current to the solenoid coil of an injector. The valve opening current and the valve holding current are supplied from the boosting circuit to a solenoid coil through the high-tension driving FET. Thus, the drive performance of the solenoid valve can be secured, and the device can be downsized by simplifying a circuit to reduce the number of parts. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a solenoid valve driving device for opening / closing a solenoid valve.

  2. Description of the Related Art Conventionally, as an electromagnetic valve driving device, there is an electromagnetic actuator driving circuit that operates a needle of a fuel injection valve disclosed in Japanese Patent Application Laid-Open No. 2001-351814. As shown in FIG. 4, the electromagnetic actuator drive circuit 11 includes a DC power supply 21, a capacitor 22, a current value control FET 32, a connection / disconnection FET 31, a resistor 33, a control circuit 54, a first diode 41, and the like. And the second diode 42.

  The capacitor 22 is an element for smoothing the output voltage of the DC power supply 21. One end of the capacitor 22 is connected to the + terminal of the DC power supply 21, and the other end is connected to the − terminal of the DC power supply 21 and grounded.

  The current value control FET 32 is a switching element that controls the current flowing through the electromagnetic coil 12 by being turned on / off based on a current setting signal from the control circuit 54. The connecting / disconnecting FET 31 is a switching element that turns on / off based on a drive signal from the control circuit 54 and thereby interrupts the current flowing through the electromagnetic coil 12. One end of the electromagnetic coil 12 is connected to a connection point between the positive terminal of the DC power supply 21 and the capacitor 22 via a current value control FET 32, and the other end is grounded via a connection / disconnection FET 31 and a current detection resistor 33. Yes.

  The first and second diodes 41 and 42 are elements for flowing a flywheel current (hereinafter referred to as a reflux current) generated when the current flowing through the electromagnetic coil 12 is interrupted. The anode of the first diode 41 is connected to the connection point between the electromagnetic coil 12 and the connection / disconnection FET 31, and the cathode is connected to the connection point between the positive terminal of the DC power supply 21 and the capacitor 22. The anode of the second diode 42 is grounded, and the cathode is connected to the connection point between the current value control FET 32 and the electromagnetic coil 12.

  Based on the drive signal from the control circuit 54, the connection / disconnection FET 31 is turned on. Further, when the current value control FET 32 repeats switching based on the current setting signal of the control circuit 54, an attraction current which is a large current for attracting the needle is supplied from the DC power source 21 and the capacitor 22 to the electromagnetic coil 12. Is done.

  When the needle suction is completed, the cutoff FET 31 is temporarily turned off based on the drive signal of the control circuit 54. When the cutoff FET 31 is turned off, a return current is generated in the electromagnetic coil 12. The return current flows from the electromagnetic coil 12 through the first diode 41, the capacitor 22, and the second diode 42 to the capacitor 22 and charges the capacitor 22. The voltage of the capacitor lowered by supplying the suction current is recovered by charging with the reflux current.

Thereafter, the current value control FET 32 repeats switching based on the current setting signal of the control circuit 54, so that a small current for holding the attracted needle to the electromagnetic coil 12 from the DC power source 21 and the capacitor 22 whose voltage has been recovered. The holding current is stably supplied.
JP 2001-351814 A

  In the electromagnetic actuator drive circuit 11 described above, the first diode 41 for charging the capacitor 22 with the reflux current generated in the electromagnetic coil 12 is necessary. Therefore, when the electromagnetic actuator drive circuit 11 is applied to an injector drive device that injects fuel into each cylinder of an engine mounted on a vehicle, the first diode 41 must be provided for each cylinder of the engine. Therefore, despite the demand for downsizing of the injector driving device, the number of parts cannot be reduced and it is difficult to downsize the device.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electromagnetic valve driving device capable of reducing the number of parts and reducing the size without reducing the driving performance of the electromagnetic valve. To do.

  Therefore, the present inventor has conducted extensive research and attempts to solve this problem, and as a result of repeating trial and error, the capacity of the boosting capacitor of the booster circuit is made large enough to supply the valve opening current and the holding current. The inventors have come up with the idea that the circuit configuration of the driving device can be simplified, and have completed the present invention.

  In other words, the electromagnetic valve driving device according to claim 1 is connected to a booster circuit that boosts and outputs an output voltage of a DC power source, and is connected between the booster circuit and a coil of the solenoid valve, thereby turning on / off. And a switching element for supplying a valve opening current for opening the solenoid valve to the coil from a booster circuit and a holding current smaller than the valve opening current for holding the valve open state after the solenoid valve is opened. In the apparatus, the booster circuit further includes a charging capacitor that is charged with a voltage obtained by boosting the output voltage of the DC power supply and has a capacity capable of supplying the suction current and the holding current to the coil. And

  According to a second aspect of the present invention, in the electromagnetic valve driving device according to the first aspect, the charging capacitor further has a capacity of 1000 μF or more.

  According to a third aspect of the present invention, there is provided the electromagnetic valve driving device according to the first or second aspect, wherein the charging capacitor is composed of a single capacitor.

  The electromagnetic valve driving device according to claim 4 is the electromagnetic valve driving device according to claim 1 or 2, wherein the charging capacitor is configured by connecting a plurality of capacitors in parallel. .

  According to a fifth aspect of the present invention, in the electromagnetic valve driving device according to the first to fourth aspects, the charging capacitor is an electrolytic capacitor.

  According to a sixth aspect of the present invention, there is provided the electromagnetic valve driving device according to any one of the first to fifth aspects, further driving an electromagnetic valve of a fuel injection device mounted on a vehicle.

  According to the electromagnetic valve driving device of the first aspect, the valve opening current and the holding current can be supplied to the coil of the electromagnetic valve by the charging capacitor constituting the booster circuit. Therefore, unlike the above-described electromagnetic actuator drive circuit, it is not necessary to charge the charging capacitor with the reflux current generated in the coil of the electromagnetic valve to restore the voltage of the charging capacitor, and the circuit can be simplified. Therefore, while ensuring the drive performance of the solenoid valve, the circuit can be simplified and the number of parts can be reduced, thereby reducing the size of the apparatus.

  According to the electromagnetic valve driving device of the second aspect, by setting the capacity of the charging capacitor to 1000 μF or more, it is possible to ensure a valve opening current and a holding current sufficient to drive the electromagnetic valve. Therefore, it is possible to reliably ensure the driving performance of the solenoid valve. The solenoid valve opens when a valve opening current flows. After the valve is opened, a holding current smaller than the valve opening current flows to maintain the valve open state. A valve opening current larger than the holding current flows only in a very short time when the valve is opened. Therefore, if the capacity of the charging capacitor is 1000 μF or more, preferably 2000 μF or more, more preferably 3000 μF or more, sufficient valve opening current and holding current can be supplied.

  According to the electromagnetic valve driving device of the third aspect, the increase in the number of parts can be suppressed by configuring the charging capacitor with one capacitor.

  According to the electromagnetic valve driving device of the fourth aspect, an optimum capacity can be freely set by configuring a charging capacitor by connecting a plurality of capacitors in parallel. Therefore, the valve opening current and the holding current are reliably ensured, and the drive performance of the solenoid valve can be prevented from being lowered.

  According to the electromagnetic valve driving device of the fifth aspect, the required capacity can be ensured and the size can be suppressed by configuring the charging capacitor with an electrolytic capacitor. Electrolytic capacitors are smaller than other types of capacitors, despite their large capacity. Therefore, the device can be further downsized while ensuring the drive performance of the solenoid valve.

  According to the electromagnetic valve driving device of the sixth aspect, the number of parts of the fuel injection device mounted on the vehicle can be reduced, and the fuel injection device can be downsized.

  This embodiment shows an example in which the electromagnetic valve driving device according to the present invention is applied to an injector driving device that injects fuel into each cylinder of an engine mounted on a vehicle.

(First embodiment)
FIG. 1 shows a circuit diagram of the injector driving device according to the first embodiment, and FIG. 2 shows a waveform of a fuel injection signal and a current waveform flowing through a solenoid coil of the injector. Then, with reference to FIG. 1 and FIG. 2, a specific description will be given in the order of configuration, operation, and effect.

  First, a specific configuration will be described. As shown in FIG. 1, the injector driving device 1 (solenoid valve driving device) includes a smoothing circuit 110, a booster circuit 111, a high voltage driving FET 112 (switching element), a high voltage driving FET driving circuit 113, The return diode 114, a cylinder selection FET 115, a solenoid coil current detection resistor 116, a cylinder selection FET drive circuit 117, and a control circuit 118 are included.

  A battery 2, an ECU 3, and injectors 4 to 7 are connected to the injector driving device 1. The battery 2 is, for example, a DC power supply with an output voltage of 12V. The ECU 3 is an electronic control device that controls the injector driving device 1 by outputting a fuel injection signal for each cylinder. The injectors 4 to 7 are fuel injection valves composed of solenoid valves having solenoid coils 4a to 7a, respectively, and are disposed in the respective cylinders of the four-cylinder engine.

  Here, the cylinder selection FET, the solenoid coil current detection resistor, and the cylinder selection FET drive circuit for the injectors 5 to 7 are the cylinder selection FET 115, the solenoid coil current detection resistor 116, and the cylinder selection FET drive circuit 117 for the injector 4. Since the configuration is the same, it is omitted.

  The smoothing circuit 110 is a circuit for smoothing the output voltage of the battery 2 that varies with the operation of the booster circuit 111. The smoothing circuit 110 includes a smoothing choke coil 110a and a smoothing capacitor 110b. One end of the smoothing choke coil 110a is connected to the positive terminal of the battery 2, and the negative terminal of the battery 2 is grounded to the vehicle body or the like. The other end of the smoothing choke coil 110a is connected to one end of the smoothing capacitor 110b, and the other end of the smoothing capacitor 110b is grounded. A connection point between the smoothing choke coil 110 a and the smoothing capacitor 110 b is connected to the booster circuit 111.

  The booster circuit 111 operates based on the output signal of the control circuit 118, and boosts and outputs the 12V output voltage of the battery 2 input via the smoothing circuit 110 to, for example, a high voltage of 85 to 105V. It is. The booster circuit 111 includes a boost choke coil 111a, a backflow prevention diode 111b, a boost FET 111c, a boost FET drive circuit 111d, a choke coil current detection resistor 111e, and a boost capacitor 111f (charging capacitor). It is composed of

  The boost choke coil 111a is an element that accumulates and releases magnetic energy and induces a voltage. One end of the boosting choke coil 111a is connected to a connection point between the smoothing choke coil 110a and the smoothing capacitor 110b constituting the smoothing circuit 110, and the other end is connected to the anode of the backflow prevention diode 111b.

  The step-up FET 111c is a switching element for controlling the current flowing through the step-up choke coil 111a. The drain of the boosting FET 111c is connected to the connection point between the boosting choke coil 111a and the backflow prevention diode 111b, the gate is connected to the boosting FET drive circuit 111d, and the source is grounded via the choke coil current detection resistor 111e. .

  The step-up FET drive circuit 111d is a circuit for switching the step-up FET 111c based on the output signal of the control circuit 118. The input terminal of the boost FET drive circuit 111d is connected to the control circuit 118, and the output terminal is connected to the gate of the boost FET 111c.

  The boosting capacitor 111f is an element for charging the boosted voltage output via the backflow prevention diode 111b. The boosting capacitor 111f has a maximum operating temperature of 120 ° C., and further has a capacity sufficient to supply an attracting current and a holding current described later to the injectors 4 to 7, for example, a high heat resistance having a capacity of 1000 μF. It is an electrolytic capacitor. One end of the boosting capacitor 111f is connected to the cathode of the backflow prevention diode 111b, the control circuit 118, and the high voltage driving FET 112, and the other end is grounded.

  The high voltage driving FET 112 is a switching element for supplying an attractive current and a holding current from the booster circuit 111 to the injectors 4 to 7. The suction current is a large current required in the initial stage of valve opening of the injectors 4 to 7. The holding current is a small current smaller than the suction current required for holding the valve open state after the injectors 4 to 7 are opened. The drain of the high voltage driving FET 112 is connected to the connection point between the backflow prevention diode 111b and the boosting capacitor 111f, the gate is connected to the high voltage driving FET driving circuit 113, and the source is connected to the freewheeling diode 114 and the injectors 4-7. Yes.

  The high voltage driving FET driving circuit 113 is a driving circuit for turning on / off the high voltage driving FET 112 based on the output signal of the control circuit 118. The input terminal of the high voltage driving FET drive circuit 113 is connected to the control circuit 118, and the output terminal is connected to the gate of the high voltage driving FET 112.

  The free-wheeling diode 114 is an element for flowing a free-wheeling current generated in the solenoid coils 4a to 7a of the injectors 4 to 7 when the high-voltage driving FET 112 is turned off. The anode of the free-wheeling diode 114 is grounded, and the cathode is connected to a connection point between the high voltage driving FET 112 and the injectors 4 to 7.

  The cylinder selecting FET 115 is a switching element for causing the suction current and the holding current supplied through the high voltage driving FET 112 to flow to the injector 4. The drain of the cylinder selection FET 115 is connected to the other end of the solenoid coil 4 a of the injector 4, the gate is connected to the cylinder selection FET drive circuit 117, and the source is grounded via the solenoid coil current detection resistor 116.

  The solenoid coil current detection resistor 116 is an element for detecting a current flowing through the solenoid coil 4 a of the injector 4. One end of the solenoid coil current detection resistor 116 is connected to the source of the cylinder selecting FET 115, and the other end is grounded. A connection point between the solenoid coil current detection resistor 116 and the cylinder selection FET 115 is connected to the control circuit 118.

  The cylinder selection FET drive circuit 117 is a drive circuit for turning on / off the cylinder selection FET 115 based on the output signal of the control circuit 118. The cylinder selection FET drive circuit 117 has an input terminal connected to the control circuit 118 and an output terminal connected to the gate of the cylinder selection FET 115.

  The control circuit 118 controls the output voltage of the booster circuit 111 and turns on / off the high voltage driving FET 112 and the cylinder selecting FET 115 based on the fuel injection signal for each cylinder from the ECU 3, thereby 7 is a circuit for controlling the fuel injection by 7. The four input terminals of the control circuit 118 are connected to the ECU 3 respectively. The other three input terminals of the control circuit 118 are a connection point between the boost FET 111c and the choke coil current detection resistor 111e, a connection point between the backflow prevention diode 111b and the boost capacitor 111f, a cylinder selection FET 115 and a solenoid. Each is connected to a connection point of the coil current detection resistor 116. Further, the three output terminals of the control circuit 118 are connected to the input terminals of the boost FET drive circuit 111d, the high voltage drive FET drive circuit 113, and the cylinder selection FET drive circuit 117, respectively.

  Next, a specific operation will be described with reference to FIG. 2 as needed with reference to FIG. As shown in FIG. 1, when an ignition switch (not shown) is turned on, the output voltage of the battery 2 is smoothed by the smoothing circuit 110 and input to the booster circuit 111. The control circuit 118 compares the voltage of the choke coil current detection resistor 111e constituting the booster circuit 111 and the voltage of the booster capacitor 111f with predetermined threshold values. Based on the comparison result, the control circuit 118 switches the boost FET 111c via the boost FET drive circuit 111d so that the voltage of the boost capacitor 111f is in the range of 85 to 105V. Thereby, the booster circuit 111 boosts the output voltage 12V of the battery 2 to a high voltage of 85 to 105V, and outputs the boosted voltage via the boosting capacitor 111f. The voltage of the boosting capacitor 111f is applied to the drain of the high voltage driving FET 112.

  When the ignition switch is turned on, the ECU 3 sequentially outputs fuel injection signals from the injectors 4 to 7. When the ECU 3 outputs the fuel injection signal of the injector 4, the control circuit 118 turns on the cylinder selection FET 115 via the cylinder selection FET drive circuit 117. Further, the control circuit 118 turns on the high voltage driving FET 112 via the high voltage driving FET driving circuit 113. When the high voltage driving FET 112 is turned on, a current flows from the booster circuit 111 to the solenoid coil 4a via the high voltage driving FET 112, the injector 4 is opened, and fuel injection into the cylinder is started. (T0 in FIG. 2)

  The current flowing through the solenoid coil 4 a is converted into a voltage by the solenoid coil current detection resistor 116 and input to the control circuit 118. When this current reaches the attraction current threshold I1, the control circuit 118 turns off the high voltage driving FET 112 via the high voltage driving FET driving circuit 113. When the high voltage driving FET 112 is turned off, the current supply from the booster circuit 111 to the solenoid coil 4a is cut off. (T1 in FIG. 2)

  When the supply of current to the solenoid coil 4a is cut off, a reflux current is generated in the solenoid coil 4a. The return current flows along a path from the solenoid coil 4a to the cylinder selection FET 115, the solenoid coil current detection resistor 116, and the ground, to the return diode 114 and the solenoid coil 4a, and gradually attenuates. After that, when the return current gradually decreases and reaches the holding current lower limit threshold I2, the control circuit 118 turns on the high voltage driving FET 112 via the high voltage driving FET driving circuit 113. When the high voltage driving FET 112 is turned on, a current flows from the booster circuit 111 to the solenoid coil 4a via the high voltage driving FET 112, the injector 4 maintains the valve open state, and fuel injection continues. (T2 in FIG. 2)

  When the current increases and reaches the holding current upper limit threshold value I3, the control circuit 118 turns off the high voltage driving FET 112 via the high voltage driving FET driving circuit 113. When the high voltage driving FET 112 is turned off, a reflux current flows through the solenoid coil 4a. (T3 in FIG. 2)

  Thereafter, the control circuit 118 turns on / off the high-voltage driving FET 112 according to the magnitude of the current flowing through the solenoid coil 4a, and controls the current within the range of the holding current lower limit threshold I2 to the upper limit threshold I3.

  When the fuel injection signal of the injector 4a from the ECU 3 is turned off, the control circuit 118 turns off the high voltage driving FET 112 via the high voltage driving FET driving circuit 113 and also turns the cylinder via the cylinder selection FET driving circuit 117. The selection FET 115 is turned off. When the high voltage driving FET 112 and the cylinder selecting FET 115 are turned off, the current of the solenoid coil 4a is cut off, and the injector 4 is closed to stop fuel injection. (T4 in FIG. 2)

  Thereafter, based on the fuel injection signals of the injectors 5 to 7 sequentially output from the ECU 3, the control circuit 118 similarly controls the currents of the solenoid coils 5a to 7a, so that the injectors 5 to 7 continuously inject fuel. .

  Finally, specific effects will be described. According to the first embodiment, the injector driving device 1 can supply the valve opening current and the holding current to the solenoid coils 4a to 7a with the boost capacitor 111f constituting the boost circuit 111. Therefore, the driving performance of the injectors 4 to 7 can be ensured, the circuit can be simplified, and the injector driving device 1 can be downsized.

  The injector driving device 1 can secure a valve opening current and a holding current sufficient to drive the injectors 4 to 7 by setting the capacity of the boosting capacitor 111f to 1000 μF. Therefore, the drive performance of the injectors 4 to 7 can be reliably ensured. The injector opens when a valve opening current flows. After the valve is opened, a holding current smaller than the valve opening current flows to maintain the valve open state. A valve opening current larger than the holding current flows only in a very short time when the valve is opened. Therefore, if the capacitance of the boosting capacitor 111f is 1000 μF, a sufficient valve opening current and holding current can be supplied.

  Moreover, the injector drive device 1 can suppress an increase in the number of parts by configuring the boosting capacitor 111f with a single capacitor.

  Furthermore, the injector driving device 1 can secure the required capacity and suppress the size by configuring the boosting capacitor 111f with an electrolytic capacitor. Therefore, the injector device 1 can be further downsized while ensuring the drive performance of the injectors 4 to 7.

  In the above-described embodiment, an example is given in which the upper limit of the use temperature of the boosting capacitor 111f is 120 ° C. and the capacitance is 1000 μF, but the present invention is not limited to this. For example, the upper limit of the operating temperature of the boosting capacitor may be 120 ° C. or higher. As a result, the heat resistance of the injector driving device is increased, so that the reliability can be further improved. Further, the capacitance of the boosting capacitor may be 1000 μF or more, preferably 2000 μF or more, more preferably 3000 μF or more. Thereby, the current capacity for driving the injector increases, and the injector can be driven more stably.

(Second Embodiment)
Next, FIG. 3 shows a circuit diagram of the injector driving device in the second embodiment. Here, only the difference from the injector driving device in the first embodiment will be described, and the description of the common parts will be omitted except for the necessary parts. In addition, the same code | symbol is attached | subjected and demonstrated to the element same as the said embodiment.

  First, a specific structure will be described. As shown in FIG. 3, the booster circuit 111 includes a boost choke coil 111a, a backflow prevention diode 111b, a boost FET 111c, a boost FET drive circuit 111d, a choke coil current detection resistor 111e, and a boost capacitor. 111g, 111h (charging capacitor).

  The boosting capacitors 111g and 111h are elements for charging the boosted voltage. The step-up capacitors 111g and 111h are, for example, electrolytic capacitors having an upper limit of 120 ° C. for use temperature and a capacity of 660 μF. One end of each of the boost capacitors 111g and 111h is connected to the cathode of the backflow preventing diode 111b, the control circuit 118, and the high voltage driving FET 112, and the other end is grounded. The two boost capacitors 111g and 111h are connected in parallel, so that the capacity of 1320 μF sufficient to supply the suction current and the holding current to the injectors 4 to 7 is obtained.

  The drain of the high voltage driving FET 112 is connected to the connection point between the backflow preventing diode 111b and the boosting capacitors 111g and 111h, the gate is connected to the high voltage driving FET driving circuit 113, and the source is connected to the freewheeling diode 114 and the injectors 4 to 7, respectively. Has been.

  Another three input terminals of the control circuit 118 are a connection point between the boost FET 111c and the choke coil current detection resistor 111e, a connection point between the backflow prevention diode 111b and the boost capacitors 111g and 111h, a cylinder selection FET 115 and a solenoid. Each is connected to a connection point of the coil current detection resistor 116.

  The operation of the injector driving device in the second embodiment is the same as that of the injector driving device in the first embodiment, except that the configuration and capacity of the boosting capacitor are changed. Therefore, the description about a specific operation is omitted.

  Finally, specific effects will be described. According to the second embodiment, the injector driving device 1 sets an optimum capacitance (in this case, 1320 μF) by configuring two boost capacitors 111g and 111h in parallel to form one boost capacitor. can do. Therefore, the valve opening current and the holding current are reliably ensured, and the drive performance of the solenoid valve can be prevented from being lowered.

  In the above-described embodiment, an example in which two boosting capacitors 111g and 111h are connected in parallel is given, but the present invention is not limited to this. For example, three or more boost capacitors may be connected in parallel. It is sufficient if the combined capacity of the plurality of boost capacitors connected in parallel is sufficient to supply the suction current and holding current of the injector.

The circuit diagram of the injector drive device in 1st Embodiment is shown. The fuel injection signal waveform in 1st Embodiment and the current waveform which flows into the solenoid coil of an injector are shown. The circuit diagram of the injector drive device in 2nd Embodiment is shown. The circuit diagram of an example of the conventional solenoid valve drive device is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Injector drive device (solenoid valve drive device), 110 ... Smoothing circuit, 110a ... Smoothing choke coil, 110b ... Smoothing capacitor, 111 ... Boosting circuit,
111a: boosting choke coil, 111b: backflow prevention diode, 111c: boosting FET, 111d: boosting FET drive circuit, 111e: choke coil current detection resistor, 111f to 111h .. Boosting capacitor (charging capacitor), 112... High voltage driving FET (switching element), 113... High voltage driving FET drive circuit, 114. FET, 116 ... solenoid coil current detection resistor, 117 ... cylinder selection FET drive circuit, 118 ... control circuit, 2 ... battery, 3 ... ECU, 4-7 ... injector 4a-7a ... Solenoid coil

Claims (6)

A booster circuit that boosts and outputs the output voltage of a DC power source, and an open circuit that opens and closes the solenoid valve from the booster circuit by being connected between the booster circuit and the solenoid valve coil. An electromagnetic valve driving device comprising: a switching element that supplies a valve current and a holding current smaller than the valve opening current that holds the valve open state after the solenoid valve is opened;
Further, the booster circuit is charged with a voltage obtained by boosting the output voltage of the DC power supply, and has a charging capacitor having a capacity capable of supplying the suction current and the holding current to the coil. Valve drive device.   The electromagnetic valve driving device according to claim 1, wherein the charging capacitor has a capacity of 1000 μF or more.   The electromagnetic valve driving device according to claim 1, wherein the charging capacitor includes a single capacitor.   The electromagnetic valve driving device according to claim 1, wherein the charging capacitor is configured by connecting a plurality of capacitors in parallel.   5. The electromagnetic valve driving device according to claim 1, wherein the charging capacitor is an electrolytic capacitor.   6. The electromagnetic valve driving device according to claim 1, wherein the electromagnetic valve of a fuel injection device mounted on a vehicle is driven.

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