JP2012147534A - Booster and booster circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a booster and a booster circuit capable of reducing ESR of an aluminum electrolytic capacitor.SOLUTION: A fixing case 30, which is tubular to enclose an aluminum electrolytic capacitor 20, includes a first fixing terminal 31 and a second fixing terminal 32 that are electrically connected to a circuit wiring 63 and fixed to a circuit board 10, on one surface 11 side of the circuit board 10 of the tube. A current is caused to flow from the first fixing terminal 31 to the second fixing terminal 32 by way of the circuit wiring 63, to heat the fixing case 30, so that the aluminum electrolytic capacitor 20 is heated. Since the temperature of the aluminum electrolytic capacitor 20 rises, the ESR of the aluminum electrolytic capacitor 20 is reduced.

Description

  The present invention relates to a booster device and a booster circuit that cause an aluminum electrolytic capacitor to generate a voltage higher than a predetermined voltage by charging the aluminum electrolytic capacitor based on a predetermined voltage.

  Conventionally, a booster circuit for boosting a capacitor until the voltage of the capacitor reaches a target voltage has been proposed in Patent Document 1, for example. Specifically, in Patent Document 1, a booster circuit is provided in a fuel injection control device that controls fuel injection to an internal combustion engine by driving a fuel injection valve (injector) that supplies fuel to each cylinder of a diesel engine. Things have been proposed.

  This booster circuit operates as a circuit for causing the capacitor to generate a boosted voltage higher than the battery voltage. An aluminum electrolytic capacitor is used as a capacitor used in the booster circuit, and the aluminum electrolytic capacitor is mounted on a circuit board.

Japanese Patent No. 4325710

  However, in the above conventional technique, since an aluminum electrolytic capacitor is used as a capacitor, ESR of the aluminum electrolytic capacitor becomes a problem. “ESR” is the total value of the resistance of the electrode, electrolyte, dielectric, etc. of the aluminum electrolytic capacitor, and varies depending on the capacity, breakdown voltage, type, etc. of the aluminum electrolytic capacitor.

  The ESR has a temperature characteristic that varies with temperature. FIG. 10 is a diagram showing temperature characteristics of ESR of the aluminum electrolytic capacitor. The horizontal axis of FIG. 10 indicates the temperature [° C.] of the aluminum electrolytic capacitor, and the vertical axis indicates ESR [Ω]. As shown in this figure, when the temperature is 0 ° C. or higher, the ERS is almost constant without depending on the temperature. However, when the temperature is lower than 0 ° C., the ESR of the aluminum electrolytic capacitor increases as the temperature decreases.

  As described above, in the booster circuit, the ESR, that is, the resistance component of the aluminum electrolytic capacitor increases, so that the boosting of the aluminum electrolytic capacitor is delayed. For this reason, there is a problem that the control of the fuel injection control device using the booster circuit is also delayed.

  In the above description, the aluminum electrolytic capacitor is used for the booster circuit of the fuel injection control device. However, the application of the booster circuit is not limited to the fuel injection control device. That is, in a circuit or device in which an aluminum electrolytic capacitor is mounted on a circuit board, an ESR problem of the aluminum electrolytic capacitor generally occurs.

  In view of the above points, an object of the present invention is to provide a booster device and a booster circuit that can reduce ESR of an aluminum electrolytic capacitor.

  In order to achieve the above object, the inventors have devised a structure capable of heating an aluminum electrolytic capacitor by utilizing a phenomenon that ESR can be reduced by increasing the temperature of the aluminum electrolytic capacitor.

  That is, in the first aspect of the present invention, the plate having one surface (11), the predetermined voltage wiring (61) to which a predetermined voltage is applied, and the reference voltage wiring to which a reference voltage lower than the predetermined voltage is applied. The circuit board (10) including the circuit wiring (63) including the circuit board (62) is mounted on the one surface (11) of the circuit board (10), and the predetermined voltage wiring (61) and the reference voltage wiring (62). An aluminum electrolytic capacitor (20) electrically connected on the path between the aluminum electrolytic capacitor (20) and charging the aluminum electrolytic capacitor (20) on the basis of a predetermined voltage. This is a booster that generates a voltage higher than a predetermined voltage at a terminal opposite to the reference voltage wiring (62) side.

  A cylindrical shape surrounding the aluminum electrolytic capacitor (20) is provided, and the first surface (11) of the cylindrical shape is electrically connected to the circuit wiring (63) and fixed to the circuit board (10). The aluminum electrolytic capacitor (20) has one fixed terminal (31) and a second fixed terminal (32), and generates heat by a current flowing through a path from the first fixed terminal (31) to the second fixed terminal (32). It has the fixed case (30) which heats.

  According to this, since the fixed case (30) functions as a heater of the aluminum electrolytic capacitor (20) when the fixed case (30) generates heat, the aluminum electrolytic capacitor (20) is heated by the fixed case (30). Thereby, since the temperature of the aluminum electrolytic capacitor (20) rises, ESR of the aluminum electrolytic capacitor (20) can be reduced.

  In the invention according to claim 2, the fixed case (30) is provided with a plate-like first strength securing portion (36) provided with the first fixed terminal (31) and a second fixed terminal (32). And a plate-like second strength securing portion (37) and a meandering plate-like heater portion (35) meandering in the same plane.

  In addition, one end portion (35a) of the heater portion (35) is connected to the side opposite to the side on which the first fixed terminal (31) is provided in the first strength securing portion (36), and the second strength is secured. The other end part (35b) of the heater part (35) is connected to the side of the securing part (37) opposite to the side on which the second fixed terminal (32) is provided.

  Also, one end (36a) different from the side where the first fixed terminal (31) is provided in the first strength securing portion (36) and the side where the one end (35a) of the heater (35) is connected. One end portion (37a) different from the side on which the second fixed terminal (32) is provided in the second strength securing portion (37) and the side to which the other end portion (35b) of the heater portion (35) is connected. Are spaced apart from each other.

  And the plate-shaped thing comprised by the 1st strength securing part (36), the 2nd strength securing part (37), and the heater part (35) is the other end part (36b) of the 1st strength securing part (36). ) And the other end portion (37b) of the second strength securing portion (37) are deformed so as to be spaced apart from each other, thereby forming a cylindrical shape. The first fixed terminal (31), The first strength securing portion (36), the heater portion (35), the second strength securing portion (37), and the second fixed terminal (32) are configured so that current flows therethrough.

  Thereby, since the path | route of the electric current which flows into a heater part (35) becomes long, resistance of a fixed case (30) can be made higher than the thing in which the heater part (35) is not formed in a fixed case (30). . Therefore, the fixed case (30) can be more easily heated.

  The invention according to claim 3 is characterized in that the first fixed terminal (31) is connected to a terminal of the aluminum electrolytic capacitor (20) opposite to the reference voltage wiring (62) side. . According to this, since a current flows through the fixed case (30) based on the voltage charged in the aluminum electrolytic capacitor (20), the aluminum electrolytic capacitor (20) can spontaneously generate heat. Thereby, the temperature increase rate of an aluminum electrolytic capacitor (20) can be improved.

  In the invention according to claim 4, the energization control is performed on the fixed case (30) by the control means (52) provided with the temperature detection means for detecting the temperature of the aluminum electrolytic capacitor (20). When the temperature detected by the temperature detection means of the control means (52) is equal to or lower than the reference temperature, the energization control is performed by the control means (52).

  According to this, since the energization is performed to the fixed case (30) at a low temperature when the ESR of the aluminum electrolytic capacitor (20) becomes a problem, the temperature of the aluminum electrolytic capacitor (20) is increased at a low temperature, and the aluminum electrolytic capacitor (20). ESR can be reduced.

  According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the control means is configured to be electrically connected on a path between the second fixed terminal (32) and the reference voltage wiring (62). 52), the fixed case (30) is controlled with a duty ratio corresponding to the temperature detected by the temperature detecting means of the control means (52). The energization control is performed by being driven by the means (52).

  According to this, since the current flowing through the fixed case (30) is controlled according to the temperature of the aluminum electrolytic capacitor (20), a larger amount of current is passed through the fixed case (30) when the temperature is low. Can generate heat. Thereby, the temperature increase rate of an aluminum electrolytic capacitor (20) can be improved.

  In particular, when the first fixed terminal (31) of the fixed case (30) is connected to the terminal of the aluminum electrolytic capacitor (20) opposite to the reference voltage wiring (62) side, the switching element (69) Is duty-driven, and the discharge of the aluminum electrolytic capacitor (20) is repeated. Therefore, the temperature of the aluminum electrolytic capacitor (20) can be raised quickly, and the ESR of the aluminum electrolytic capacitor (20) can be reduced quickly.

  In the invention of claim 6, in the invention of claims 4 and 5, the fixed case (30) is controlled such that the temperature detected by the temperature detecting means of the control means (52) is not more than the reference temperature. After the determination by the means (52), the energization control is forcibly performed by the control means (52) until a predetermined time elapses. Thereby, since a current flows through the fixed case (30) for a certain time, the fixed case (30) can be forcibly heated to heat the aluminum electrolytic capacitor (20).

  In the invention according to claim 7, the predetermined voltage is a power supply voltage generated by a power supply, and the aluminum electrolytic capacitor (20) is charged based on the power supply voltage, and the aluminum electrolytic capacitor (20) Each time the fuel injection timing to the internal combustion engine arrives, the actuator for opening the fuel injection valve (40) is discharged as drive power for the actuator.

  As described above, when the booster is used for an internal combustion engine, the ESR of the aluminum electrolytic capacitor (20) is reduced as described above, so that the aluminum electrolytic capacitor (20) to the fuel injection valve (40) is reduced. Since the discharge current does not decrease, the opening of the fuel injection valve (40) during the low temperature start of the internal combustion engine can be prevented from being delayed.

  In the above description, the booster device is described as having the fixed case (30) installed on the circuit board (10). However, the fixed case (30) can also be configured as a booster circuit that functions as a heater resistor.

  That is, in the invention according to claim 8, in the circuit wiring (63) including the predetermined voltage wiring (61) to which the predetermined voltage is applied and the reference voltage wiring (62) to which the reference voltage lower than the predetermined voltage is applied. The aluminum electrolytic capacitor (20) electrically connected on the path between the predetermined voltage wiring (61) and the reference voltage wiring (62) is provided, and the aluminum electrolytic capacitor (20) is charged based on the predetermined voltage. Thus, the booster circuit generates a voltage higher than a predetermined voltage at a terminal opposite to the reference voltage wiring (62) side of the aluminum electrolytic capacitor (20), and is characterized by the following points.

  And it has the 1st terminal (31) and the 2nd terminal (32), the 1st terminal (31) is electrically connected to circuit wiring (63), and the 2nd terminal (32 from the 1st terminal (31)) ) Is provided with a heater resistor (30) that heats the aluminum electrolytic capacitor (20) by generating heat by the current flowing through it.

  In addition, the heater resistance (30) is electrically connected to the path between the second terminal (32) of the heater resistance (30) and the reference voltage wiring (62), and driven by the control means (52), so that the heater resistance A switching element (69) for energizing (30) is provided.

  According to this, since the aluminum electrolytic capacitor (20) is heated when the heater resistor (30) generates heat, the temperature of the aluminum electrolytic capacitor (20) rises. Therefore, ESR of the aluminum electrolytic capacitor (20) can be reduced.

  The invention according to claim 9 is characterized in that the first terminal (31) is connected to a terminal of the aluminum electrolytic capacitor (20) opposite to the reference voltage wiring (62) side. According to this, since the current flows through the heater resistor (30) based on the voltage charged in the aluminum electrolytic capacitor (20), the aluminum electrolytic capacitor (20) can spontaneously generate heat. Thereby, the temperature increase rate of an aluminum electrolytic capacitor (20) can be improved.

  In the invention according to claim 10, the switching element (69) is configured such that the control means (69) when the temperature of the aluminum electrolytic capacitor (20) detected by the temperature detection means provided in the control means (52) is equal to or lower than the reference temperature. 52).

  According to this, since the heater element (30) is energized by the switching element (69) at a low temperature when the ESR of the aluminum electrolytic capacitor (20) becomes a problem, the aluminum electrolytic capacitor (20) is heated at a low temperature. The ESR of the aluminum electrolytic capacitor (20) can be reduced.

  According to an eleventh aspect of the present invention, in the invention according to the tenth aspect, the switching element (69) has a duty according to the temperature of the aluminum electrolytic capacitor (20) detected by the temperature detecting means of the control means (52). Driven by the control means (52) in a ratio.

  According to this, since the current flowing through the heater resistor (30) is controlled according to the temperature of the aluminum electrolytic capacitor (20), a larger amount of current is passed through the heater resistor (30) at a low temperature so that the heater resistor (30) is supplied. It can make it easy to generate heat. Thereby, the temperature increase rate of an aluminum electrolytic capacitor (20) can be improved.

  In the invention described in claim 12, in the invention described in claims 10 and 11, the switching element (69) is based on the temperature of the aluminum electrolytic capacitor (20) detected by the temperature detecting means of the control means (52). After the controller (52) determines that the temperature is equal to or lower than the temperature, the controller is forcibly driven by the controller (52) until a predetermined time elapses. Thereby, since a current flows through the fixed case (30) by the control means (52) for a certain time, the fixed case (30) can be forcibly heated to heat the aluminum electrolytic capacitor (20).

  In the invention according to claim 13, the predetermined voltage is a power supply voltage generated by a power supply, and the aluminum electrolytic capacitor (20) is charged based on the power supply voltage, and the aluminum electrolytic capacitor (20) Each time the fuel injection timing to the internal combustion engine arrives, the actuator for opening the fuel injection valve (40) is discharged as drive power for the actuator.

  Thus, when the booster circuit is used for an internal combustion engine, the ESR of the aluminum electrolytic capacitor (20) is reduced as described above, and therefore, the aluminum electrolytic capacitor (20) to the fuel injection valve (40). Since the discharge current does not decrease, the opening of the fuel injection valve (40) during the low temperature start of the internal combustion engine can be prevented from being delayed.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

1 is an external view of a boost power supply device according to a first embodiment of the present invention. It is a figure of the end surface of a fixed case when a fixed case is seen from the upper part of a circuit board to the circuit board side. FIG. 3 is a development view of the fixed case shown in FIG. 2. It is a circuit block diagram of the fuel-injection control apparatus to which the pressure | voltage rise power supply device shown by FIG. 1 was applied. It is the figure which showed the electric current I which flows into a coil, the discharge | release electric charge from an aluminum electrolytic capacitor, and the valve opening timing of an injector with respect to time, respectively. It is a figure for demonstrating that the valve opening timing of an injector is delayed at the time of low temperature. It is the flowchart which showed the content of the heating control of a microcomputer. It is the figure which showed drive duty with respect to ECU internal temperature Ta. It is an expanded view of the fixed case which concerns on 2nd Embodiment of this invention. It is a figure for demonstrating a subject.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The booster according to the present embodiment is used as a power booster that generates a voltage higher than a power supply voltage, and is applied to a fuel injection control device that controls fuel injection to an internal combustion engine.

  The fuel injection control device is a device that drives four fuel injection valves (referred to as injectors) that inject and supply fuel to each cylinder of a multi-cylinder (for example, four cylinder) diesel engine mounted on a vehicle. This fuel injection control device controls the energization time and energization timing to the solenoid coil built in each injector, and controls the fuel injection amount and fuel injection timing to each cylinder of the diesel engine.

  FIG. 1 is an external view of a boost power supply device according to this embodiment. As shown in this figure, the boost power supply device includes a circuit board 10, an aluminum electrolytic capacitor 20, and a fixed case 30.

  The circuit board 10 is a plate having one surface 11, and includes a power supply voltage wiring to which a power supply voltage that is a battery voltage is applied from a vehicle-mounted battery, and a reference voltage wiring to which a reference voltage lower than the power supply voltage is applied. Circuit wiring is formed. In this embodiment, the reference voltage is ground. Of course, the reference voltage may be set to a voltage other than the ground.

  The aluminum electrolytic capacitor 20 is a cylindrical electrolytic capacitor having two polar terminals. As shown in FIG. 1, the aluminum electrolytic capacitor 20 is mounted on one surface 11 of the circuit board 10 and is electrically connected on a path between the power supply voltage wiring and the reference voltage wiring.

  The aluminum electrolytic capacitor 20 is charged based on the power supply voltage, thereby generating a voltage higher than a predetermined voltage at a terminal of the aluminum electrolytic capacitor 20 opposite to the reference voltage wiring side. The voltage charged in the aluminum electrolytic capacitor 20 is used for valve opening control of the electromagnetic valve of the internal combustion engine.

  The fixed case 30 is a case for preventing the aluminum electrolytic capacitor 20 from vibrating and fixing the aluminum electrolytic capacitor 20 to the circuit board 10. As shown in FIG. 1, the fixed case 30 is cylindrical. The aluminum electrolytic capacitor 20 is disposed in the hollow portion of the fixed case 30. That is, the fixed case 30 surrounds the aluminum electrolytic capacitor 20.

  A first fixed terminal 31 and a second fixed terminal 32 are provided on the surface 11 side of the circuit board 10 in the cylindrical fixed case 30. The first fixed terminal 31 and the second fixed terminal 32 are electrically connected to circuit wiring provided on the circuit board 10 and are fixed to the circuit board 10. The fixed case 30 also serves as a heater resistor that heats the aluminum electrolytic capacitor 20 by generating heat due to the current flowing through the path from the first fixed terminal 31 to the second fixed terminal 32. Such a fixed case 30 is formed of a metal material such as stainless steel (SUS) or tungsten, for example.

  Specifically, the shape of the fixed case 30 will be described with reference to FIGS. 2 and 3. FIG. 2 is a view of the end surface of the fixed case 30 when the circuit board 10 side is viewed from above the circuit board 10. FIG. 3 is a development view of the fixed case 30.

  As described above, the fixed case 30 has a cylindrical shape, but this is bent and deformed so that the end 33a and the end 33b of one metal plate are spaced apart from each other as shown in FIG. It has become a cylindrical shape by being made. When such a cylindrical fixed case 30 is developed, as shown in FIG. 3, the fixed case 30 includes a strength securing portion 34 and a heater portion 35.

  The strength securing portion 34 is a portion of the fixed case 30 on the circuit board 10 side, and is a portion functioning for vibration resistance of the aluminum electrolytic capacitor 20. The strength securing portion 34 includes a square plate-shaped first strength securing portion 36 and a square plate-shaped second strength securing portion 37.

  The first strength securing unit 36 includes a first fixed terminal 31 and a third fixed terminal 38, and the second strength securing unit 37 includes a second fixed terminal 32 and a fourth fixed terminal 39. The third fixed terminal 38 and the fourth fixed terminal 39 are terminals for balancing the fixed case 30 with respect to the first fixed terminal 31 and the second fixed terminal 32 by contacting the one surface 11 of the circuit board 10. The circuit wiring 63 is not electrically connected.

  The heater portion 35 is a meandering plate-like portion that meanders in the same plane, and is the portion that generates the most heat in the fixed case 30. One end portion 35a of the heater portion 35 is connected to a side opposite to the side (side) on which the first fixed terminal 31 is provided in the rectangular first strength securing portion 36 and the other end of the heater portion 35. The part 35b is connected to the side opposite to the side (side) on which the quadrangular second fixed terminal 32 is provided in the second strength securing part 37.

  Further, one end 35 a of the heater unit 35 is connected to the other end 36 b side of the first strength securing unit 36 opposite to the one end 36 a, and the other end 35 b of the heater 35 is connected to the second strength securing unit 37. Is connected to the other end 37b side opposite to the one end 37a.

  Also, the side (side) on which the first fixed terminal 31 and the third fixed terminal 38 are provided and the side (side) to which the one end portion 35a of the heater unit 35 is connected in the first strength securing portion 36 having a rectangular shape. A different end portion 36a, a side (side) where the second fixed terminal 32 and the fourth fixed terminal 39 are provided in the second strength securing portion 37, and a side (side) where the other end portion 35b of the heater portion 35 is connected. One end portion 37a different from that is spaced from and opposed to the one end portion 37a. The first strength securing portion 36 and the second strength securing portion 37 are not directly electrically connected, but are electrically connected via the heater portion 35. This state is a plan view shown in FIG.

  The plate-like member constituted by the first strength securing portion 36, the second strength securing portion 37, and the heater portion 35 shown in FIG. 3 is the other end portion 36b of the first strength securing portion 36 and the second strength. The securing part 37 is deformed into a square columnar cylinder by a press or the like so that the other end part 37b of the securing part 37 is spaced apart and disposed. Further, in the heater portion 35, four portions marked with “★” shown in FIG. 3 are bent inside the fixed case 30 as shown in FIG. The portion marked with “★” functions as a fixing spring mechanism for pressing the aluminum electrolytic capacitor 20.

In such a configuration, a current flows in a path from the first fixed terminal 31 to the second fixed terminal 32 through the first strength securing portion 36, the heater portion 35, and the second strength securing portion 37. As described above, a part of the heater unit 35 is in contact with the aluminum electrolytic capacitor 20 as a fixing spring mechanism. However, since the aluminum electrolytic capacitor 20 is generally coated with an insulating film, an electrical failure is caused. Does not occur.

  Next, a circuit configuration of the fuel injection control device when the boosting power supply device using the fixed case 30 is applied to the fuel injection control device will be described with reference to FIG. In FIG. 4, one of the four injectors 40 is shown. Below, the drive of this one injector 40 is demonstrated.

  First, the fuel injection control device 50 is provided with a booster circuit 60 as a booster power supply device. The booster circuit 60 is a so-called DC-DC converter. The booster circuit 60 is supplied with a power supply voltage wiring 61 connected to a power supply wiring 51 to which a battery voltage (VB in FIG. 4) of an in-vehicle battery as a power supply voltage is supplied, and a reference voltage lower than the power supply voltage. A circuit wiring 63 including a reference voltage wiring 62 is formed.

  Further, a battery voltage (VB in FIG. 4) is supplied to one end of a coil 64 provided in the booster circuit 60 via a power supply voltage wiring 61, and a path between the other end of the coil 64 and the reference voltage wiring 62 is supplied. The switching element 65 is connected. A MOSFET is used as the switching element 65, and the drain of the switching element 65 is connected to the other end of the coil 64.

  The anode of the diode 66 is connected to the current path connecting the other end of the coil 64 and the drain of the switching element 65, and the charging path is connected to the path between the cathode of the diode 66 and the reference voltage wiring 62. Aluminum electrolytic capacitors 20 are connected in series. Further, the source of the switching element 65 and the terminal of the aluminum electrolytic capacitor 20 opposite to the diode 66 side are connected to the reference voltage wiring 62 via a current detection resistor 67.

  The booster circuit 60 is provided with a charge control circuit 68. The charging control circuit 68 allows a processing unit including a microcomputer (hereinafter referred to as a microcomputer) or a logic circuit (not shown) and information used for controlling the switching element 65 to be taken into the processing unit, or in response to a command from the processing unit. And a combination with an analog circuit for driving the switching element 65.

  Furthermore, the above-described fixed case 30 is incorporated in the booster circuit 60 as a heater resistor. Specifically, the first fixed terminal 31 of the fixed case 30 is connected to the cathode of the diode 66 via the circuit wiring 63, that is, the terminal on the side opposite to the reference voltage wiring 62 side of the aluminum electrolytic capacitor 20. Yes. On the other hand, a switching element 69 is connected on the path between the second fixed terminal 32 of the fixed case 30 and the reference voltage wiring 62. The switching element 69 energizes the fixed case 30 by being driven by the microcomputer 52 provided in the fuel injection control device 50. As a result, the fixed case 30 generates heat due to the current flowing from the first fixed terminal 31 to the second fixed terminal 32. The above is the configuration of the booster circuit 60. Such a booster circuit 60 is built in the circuit board 10 shown in FIG.

  The fuel injection control device 50 is provided with a terminal 53a to which one end (high voltage side) of the coil 41 of the injector 40 is connected and a terminal 53b to which the other end (low voltage side) of the coil 41 is connected. It has been. A switching element 54a and a backflow preventing diode 55a are connected in series between the power supply line 51 and the terminal 53a. The anode of the diode 55a is connected to the switching element 54a, and the cathode is connected to the terminal 53a. In addition, a diode 55b having an anode connected to the ground and a cathode connected to the terminal 53a is provided on the path between the terminal 53a and the ground. The ground of the fuel injection control device 50 is connected to the reference power supply wiring 51 of the booster circuit 60.

  A switching element 54 b is connected between the positive electrode side terminal (terminal on the diode 66 side) of the aluminum electrolytic capacitor 20 in the booster circuit 60 and the terminal 53 a of the fuel injection control device 50.

  On the other hand, between the positive electrode side terminal (terminal on the diode 66 side) of the aluminum electrolytic capacitor 20 in the booster circuit 60 and the terminal 53b of the fuel injection control device 50, an anode is connected to the terminal 53b and the cathode is made of aluminum. A diode 55c connected to the positive electrode side terminal (terminal on the diode 66 side) of the electrolytic capacitor 20 is provided. A switching element 54c and a current detection resistor 56 are connected in series on a path between the terminal 53b of the fuel injection control device 50 and the ground.

  Further, the fuel injection control device 50 is provided with a drive control circuit 57 and a microcomputer 52. The drive control circuit 57 is a circuit that controls the switching elements 54 a, 54 b, 54 c and the charge control circuit 68 of the booster circuit 60. The microcomputer 52 is a control circuit that includes a CPU, a ROM, a RAM, and the like and operates according to a program stored in the ROM. Here, the microcomputer 52 generates an injection command signal for each cylinder based on engine operation information detected by various sensors such as the engine speed (NE), the accelerator opening (ACC), and the engine water temperature (THW). It is generated and output to the drive control circuit 57.

  Further, the microcomputer 52 includes temperature detection means (not shown) for detecting the temperature of the aluminum electrolytic capacitor 20. Here, the temperature detecting means means means for directly acquiring the temperature of the aluminum electrolytic capacitor 20 based on a signal from a temperature sensor provided in the fuel injection control device 50, or a signal such as an intake air temperature input from the outside. The temperature of the aluminum electrolytic capacitor 20 is indirectly obtained by estimating the temperature of the aluminum electrolytic capacitor 20 based on the above.

  The fuel injection control device 50 is constructed as an ECU, for example, built in the circuit board 10 shown in FIG. That is, the booster circuit 60 is built in the ECU. Note that MOSFETs are used as the switching elements 54a, 54b, and 54c. Further, the terminal 53a of the fuel injection control device 50 is a common terminal for the coil 41 of the injector 40 of each cylinder, and the coil 41 of each injector 40 is connected thereto. Further, the terminal 53b and the switching element 54c are provided for each coil 41 of each injector 40, respectively. The switching element 54c is a so-called cylinder selection switch.

  The injector 40 connected to the terminal 53a and the terminal 53b of the fuel injection control device 50 is a known solenoid injector provided with a solenoid as a valve opening actuator. That is, in the injector 40, when the coil 41 of the built-in solenoid is energized, the valve body is moved to the valve open position by the solenoid, the injector 40 is opened, and fuel injection is performed. When energization of the coil 41 is stopped, the valve body returns to the valve closing position, the injector 40 is closed, and fuel injection is stopped.

  Next, the operation of the fuel injection control device 50 and the booster circuit 60 will be described. Hereinafter, only the first cylinder will be described.

  First, before the start of fuel injection, the drive control circuit 57 sets the charge permission signal for the charge control circuit 68 of the booster circuit 60 to the active level, and the capacitor voltage VC of the aluminum electrolytic capacitor of the booster circuit 60 reaches the target charge voltage. Charged. The active level is, for example, a high level signal, and the inactive level is, for example, a low level signal.

  Specifically, the switching element 65 is turned on by the charge control circuit 68 of the booster circuit 60. Along with this, a current Im flowing in the coil 64 via the switching element 65 is detected by the charge control circuit 68 due to the voltage generated in the resistor 67. When the charging control circuit 68 determines that the current Im has increased to a predetermined threshold value, the switching element 65 is turned off.

  Further, the current Im flowing from the coil 64 to the aluminum electrolytic capacitor 20 is detected by the charge control circuit 68 by the voltage generated in the resistor 67 when the switching element 65 is off. When the charging control circuit 68 determines that the current Im has decreased to a predetermined threshold, the switching element 65 is turned on.

  As described above, the switching element 65 is repeatedly turned on / off, whereby the aluminum electrolytic capacitor 20 is charged stepwise based on the power supply voltage. When the charge control circuit 68 detects that the capacitor voltage VC charged in the aluminum electrolytic capacitor 20 has reached the target charge voltage, or when the charge permission signal from the drive control circuit 57 becomes an inactive level, the charge is performed. The switching element 65 is turned off by the control circuit 68.

  Next, in the fuel injection control device 50, the first cylinder injection command signal is input from the microcomputer 52 to the drive control circuit 57. Then, the switching element 54c is turned on by the drive control circuit 57, and at the same time, the switching element 54b is also turned on.

  As a result, the capacitor voltage VC is applied to the terminal 53 a that forms the energization path to the coil 41, and the energy charged in the aluminum electrolytic capacitor 20 is released to the coil 41. Thus, energization of the coil 41 is started. At this time, a large current I (peak current) for quickly opening the injector 40 flows through the coil 41 due to the discharge of the aluminum electrolytic capacitor 20. Further, when the aluminum electrolytic capacitor 20 is discharged, the wraparound from the terminal 53a side to the power supply wiring 51 side, which is at a high potential, is prevented by the diode 55a.

  FIG. 5 is a diagram showing the current I flowing through the coil 41, the electric charge discharged from the aluminum electrolytic capacitor 20, and the valve opening timing of the injector 40 with respect to time. As shown in this figure, the discharge of the aluminum electrolytic capacitor 20 increases the discharge charge, and the current I flowing through the coil 41 increases. The current I flowing through the coil 41 corresponds to the discharge current of the aluminum electrolytic capacitor 20.

  In the drive control circuit 57, after the switching element 54b is turned on, the current I flowing through the coil 41 is detected by a voltage generated in the resistor 56, and this current I is detected as a target current value of a peak current (a predetermined discharge current detection threshold value). ) When Ip, the switching element 54b is turned off. In addition, as shown in FIG. 5, when the electric charge discharged from the aluminum electrolytic capacitor 20 reaches the electric charge necessary for opening the injector 40, the injector 40 is opened. The “charge necessary for opening the valve” corresponds to “energy” necessary for opening the injector 40.

  After the switching element 54b is turned off, the on / off control of the switching element 54a is performed so that the current I of the coil 41 detected by the voltage generated in the resistor 56 becomes a constant current smaller than the target current value Ip. Done.

  Specifically, when the current I of the coil 41 becomes lower than the lower threshold value IcL shown in FIG. 5, the switching element 54a is turned on, and when the current I of the coil 41 becomes higher than the upper threshold value IcH, the switching element 54a is turned off. Control is performed. Therefore, when the current I of the coil 41 decreases from the target current value Ip of the peak current and becomes equal to or lower than the lower threshold value IcL, the switching element 54a is repeatedly turned on / off, and the average value of the current I of the coil 41 becomes higher. It is controlled to a constant current that is substantially between the threshold value IcH and the lower threshold value IcL.

  After the switching element 54b is turned off by such constant current control, a constant current flows from the power supply wiring 51 to the coil 41 via the switching element 54a and the diode 55a, and the injector 40 is opened by this constant current. Held in a state. Note that the current flowing through the coil 41 when the switching element 54a is turned off is circulated through the diode 55b.

  Thereafter, when the injection command signal from the microcomputer 52 becomes an inactive level, the switching element 54c is turned off by the drive control circuit 57, and the on / off control (constant current control) of the switching element 54a is terminated and the switching is performed. The element 54a is also kept off. Thereby, the energization to the coil 41 is stopped, the injector 40 is closed, and the fuel injection by the injector 40 is finished. In the fuel injection control as described above, the aluminum electrolytic capacitor 20 is discharged as drive power for the solenoid to an actuator for opening the injector 40, that is, a solenoid each time the fuel injection timing to the internal combustion engine arrives.

  Further, when the injection command signal becomes an inactive level and the switching element 54c and the switching element 54a are turned off, flyback energy is generated in the coil 41. The flyback energy is transmitted to the aluminum electrolytic capacitor 20 through the diode 55c. It is recovered in the form of current.

  Note that while the injection command signal output from the drive control circuit 57 is at the active level, the charge permission signal to the charge control circuit 68 is set to the inactive level, and the boosting circuit 60 charges the aluminum electrolytic capacitor 20. Is prohibited. When the injection command signal becomes an inactive level, the charging permission signal is returned to the active level, and the charging operation of the aluminum electrolytic capacitor 20 by the booster circuit 60 is resumed. The injectors 40 other than the first cylinder are also driven in the same procedure as described above. The above is the normal operation of the fuel injection control device 50 and the booster circuit 60.

  In the fuel injection control device 50 and the booster circuit 60 that operate as described above, the valve opening timing of the injector 40 is delayed at low temperatures due to the ESR, that is, the resistance component of the aluminum electrolytic capacitor 20. This will be described with reference to FIG. FIG. 6 is a diagram showing the current I flowing through the coil 41, the electric charge discharged from the aluminum electrolytic capacitor 20, and the valve opening timing of the injector 40 with respect to time, as in FIG.

  First, when electric charges are discharged from the aluminum electrolytic capacitor 20 to the coil 41 by the discharge of the aluminum electrolytic capacitor 20, the rising speed (that is, the time constant) of the current I flowing through the coil 41 is equal to the ESR (resistance component) of the aluminum electrolytic capacitor 20. It is determined by the reactor portion of the coil 41. In this case, the time constant is proportional to the reactor and inversely proportional to the resistance component.

  As described above, the ESR (resistance component) of the aluminum electrolytic capacitor 20 increases at low temperatures. Therefore, when the ESR (resistance component) of the aluminum electrolytic capacitor 20 is large during the discharge of the aluminum electrolytic capacitor 20, the rising speed of the current I flowing through the coil 41 is slow as shown by the broken line in FIG. In addition, the rise in the charge released from the aluminum electrolytic capacitor 20 is also slowed down. For this reason, the time until the electric charge discharged from the aluminum electrolytic capacitor 20 reaches the electric charge necessary for opening the injector 40 is also delayed. As a result, the valve opening timing of the injector 40 is delayed as compared with the case where the ESR of the aluminum electrolytic capacitor 20 is not a problem.

  Therefore, the microcomputer 52 of the fuel injection control device 50 controls the heating of the fixed case 30 that functions as a heater resistance. This heating control will be described with reference to FIGS. FIG. 7 is a flowchart showing the contents of the heating control of the microcomputer 52. This flowchart starts when the ignition of the vehicle is turned on.

  In FIG. 7, in step 70, the internal temperature Ta of the ECU that is the fuel injection control device 50 is detected. Subsequently, in step 71, it is determined whether or not the ECU internal temperature Ta detected in step 70 is equal to or lower than the heater drive permission temperature TaO. The heater drive permission temperature TaO is a reference temperature for determining whether or not the energization control is performed on the fixed case 30, and the ESR of the aluminum electrolytic capacitor 20 becomes a problem at a temperature lower than the reference temperature. In the present embodiment, the heater drive permission temperature TaO is set to 0 ° C., for example.

  If the ECU internal temperature Ta is not lower than the heater drive permission temperature TaO, that is, if the ECU internal temperature Ta is higher than the heater drive permission temperature TaO, the routine proceeds to step 72. In step 72, the ECU internal temperature Ta is a temperature at which the ESR of the aluminum electrolytic capacitor 20 does not cause a problem, and it is not necessary to heat the aluminum electrolytic capacitor 20, so that “heater driving = OFF” is set. That is, the energization control for the fixed case 30 is not performed.

  As will be described in step 73, in this embodiment, the switching element 69 connected to the fixed case 30 is duty-driven. Therefore, “heater driving = OFF” in step 71 means that the duty of the switching element 69 is 0%. Is set to

  Thereafter, the process returns to step 70, and step 70, step 71, and step 72 are repeated as long as the ECU internal temperature Ta continues to be higher than the heater drive permission temperature TaO.

  On the other hand, if the ECU internal temperature Ta is equal to or lower than the heater drive permission temperature TaO in step 71, the process proceeds to step 73. In step 73, the heater drive duty is set.

  FIG. 8 is a diagram showing the drive duty with respect to the ECU internal temperature Ta. The drive duty is a duty ratio for driving the switching element 69 connected to the fixed case 30 and is a duty ratio according to the temperature of the aluminum electrolytic capacitor 20. As shown in FIG. 8, the drive duty is set to be higher as the ECU internal temperature Ta is lower. This corresponds to the ESR characteristic of the aluminum electrolytic capacitor 20 shown in FIG.

  Therefore, in step 73, the drive duty for the ECU internal temperature Ta is set based on the relationship shown in FIG.

  Subsequently, in step 74, “heater driving = ON” is set. That is, the switching element 69 is driven by the driving duty corresponding to the temperature of the aluminum electrolytic capacitor 20 set in step 73. In this way, energization control for the fixed case 30 is performed.

  Thus, the energization control is performed on the fixed case 30 by the switching element 69 at a low temperature when the ESR of the aluminum electrolytic capacitor 20 is a problem, and the aluminum electrolytic capacitor 20 is heated and heated by the fixed case 30 at a low temperature. If the temperature of the aluminum electrolytic capacitor 20 rises, the ESR of the aluminum electrolytic capacitor 20 is reduced.

  In this case, as described above, the first fixed terminal 31 of the fixed case 30 is connected to the terminal of the aluminum electrolytic capacitor 20 opposite to the reference voltage wiring 62 side. A discharge current based on the capacitor voltage charged in the capacitor 20 flows. For this reason, the aluminum electrolytic capacitor 20 can be caused to perform a work called “discharge” to cause the aluminum electrolytic capacitor 20 to generate heat spontaneously. Thereby, the temperature increase rate of the aluminum electrolytic capacitor 20 is improved.

  Thereafter, the process returns to Step 70, and Step 70, Step 71, Step 73, and Step 74 are repeated as long as the ECU internal temperature Ta continues to be equal to or lower than the heater drive permission temperature TaO.

  As described above, the ESR of the aluminum electrolytic capacitor 20 is reduced by causing the fixed case 30 to function as a heater at a low temperature. For this reason, since the discharge current from the aluminum electrolytic capacitor 20 to the injector 40 does not decrease, as shown in FIG. 6, the valve opening timing of the injector 40 caused by the ESR of the aluminum electrolytic capacitor 20 at the low temperature start of the internal combustion engine is shown. There is no delay, and the injector 40 can be opened at the normal timing indicated by the solid line waveform.

  As described above, the present embodiment is characterized in that the energization control is performed on the fixed case 30 for fixing the aluminum electrolytic capacitor 20 provided in the boost power supply device to the circuit board 10. It has become.

  Thereby, the aluminum electrolytic capacitor 20 can be heated by generating heat in the fixed case 30. Thereby, since the temperature of the aluminum electrolytic capacitor 20 rises, ESR of the aluminum electrolytic capacitor 20 can be reduced. That is, it is not necessary to use an aluminum electrolytic capacitor with good ESR characteristics at low temperatures, and the ESR of the existing aluminum electrolytic capacitor 20 can be reduced by energization control of the fixed case 30.

  In this case, since the switching element 69 is driven by the duty ratio corresponding to the temperature of the aluminum electrolytic capacitor 20, the current flows through the fixed case 30 as the temperature of the aluminum electrolytic capacitor 20 decreases, and the fixed case 30 generates heat. be able to. Thereby, the temperature increase rate of the aluminum electrolytic capacitor 20 can be improved.

  Further, since the fixed case 30 is connected to the aluminum electrolytic capacitor 20, the discharge of the aluminum electrolytic capacitor 20 is repeated when the switching element 69 is duty-driven. For this reason, the temperature of the aluminum electrolytic capacitor 20 can be raised quickly, and the ESR of the aluminum electrolytic capacitor 20 can be reduced quickly. That is, unlike the conventional case, it is not necessary to perform an excessive control operation such as increasing the number of times of charging / discharging the aluminum electrolytic capacitor 20 at a low temperature to increase the temperature by self-heating of the aluminum electrolytic capacitor 20. In addition, there is no need to limit the injection frequency during the temperature raising period until the aluminum electrolytic capacitor 20 reaches a certain temperature because of concern that the valve opening timing of the injector 40 will be delayed.

  Further, in the present embodiment, since the high resistance stainless steel (SUS) is adopted as the material of the fixed case 30 and the meandering heater portion 35 is provided, the heater portion 35 is formed in the fixed case 30. The resistance of the fixed case 30 is higher than that of the non-exposed one, and the fixed case 30 can easily generate heat.

  And since the problem of ESR of the aluminum electrolytic capacitor 20 is solved at an early stage by the energization control of the fixed case 30, it is particularly effective for a circuit that "I want to use it immediately in a low temperature range".

  As for the correspondence between the description of the present embodiment and the description of the claims, the power supply voltage wiring 61 corresponds to the “predetermined voltage wiring” in the claims, and the fixed case 30 corresponds to “ Corresponds to “heater resistance”. Further, the first fixed terminal 31 of the fixed case 30 corresponds to a “first terminal” in the claims, and the second fixed terminal 32 of the fixed case 30 corresponds to a “second terminal” in the claims. Further, the microcomputer 52 corresponds to “control means” in the claims.

(Second Embodiment)
In the present embodiment, parts different from the first embodiment will be described. For example, in the past, brass strip (DC2600R) was used as the material of the fixed case 30, but high resistance can be obtained simply by using stainless steel (SUS) as the material of the fixed case 30 as in the first embodiment. It is done.

  Therefore, as shown in FIG. 9, even if the heater part 35 is not provided in the fixed case 30, the fixed case 30 can be easily heated only by being formed of stainless steel (SUS). be able to. As shown in FIG. 9, also in the fixed case 30 according to the present embodiment, a plurality of spring portions 30 a for pressing the aluminum electrolytic capacitor 20 are formed. The “★” mark shown in FIG. 9 corresponds to the “★” mark shown in FIG.

(Other embodiments)
The configurations of the fuel injection control device 50 and the step-up power supply device shown in the above embodiments are examples, and the present invention is not limited to the configurations shown above, and other configurations including the features of the present invention may be adopted. it can. For example, the boosting power supply device is configured to boost the battery voltage, but may be configured as a boosting device that generates a voltage higher than the predetermined voltage by charging the aluminum electrolytic capacitor 20 based on the predetermined voltage. good. Of course, the boosting power supply device (boosting device) and the boosting circuit 60 are not limited to the fuel injection control device 50, and may be applied to other devices that use the boosted voltage.

  Further, the control means for driving the switching element 69 connected to the fixed case 30 is not limited to the microcomputer 52, and another control circuit may drive the switching element 69.

  Further, in the energization control for the fixed case 30, in order to increase the temperature of the aluminum electrolytic capacitor 20, if it is determined in step 71 shown in FIG. 7 that the ECU internal temperature Ta is equal to or lower than the heater drive permission temperature TaO, the determination is made. Thereafter, the energization control may be forcibly performed on the fixed case 30 by forcibly driving the switching element 69 by the microcomputer 52 until a predetermined time elapses. Thereby, since a current flows through the fixed case 30 for a certain time, the fixed case 30 can be surely heated to heat the aluminum electrolytic capacitor 20 early.

  And control with respect to the switching element 69 made to supply with electricity to the fixed case 30 is not restricted to duty driving, but may be control that always flows current. Of course, the duty drive is not limited to the relationship shown in FIG. 8, and other relationships may be used.

  Furthermore, as means for increasing the resistance of the fixed case 30, as described above, in addition to the means for providing the heater portion 35 and stainless steel (SUS), for example, a plurality of metal plates constituting the fixed case 30 are provided. It is also possible to increase the resistance by providing a through hole. For example, in the fixed case 30 shown in FIG. 9, a plurality of penetrating terms can be provided on the side opposite to the side where the first fixed terminals 31 and the like are provided.

  Further, in each of the embodiments described above, the fixed case 30 is configured as a quadrangular prismatic cylinder, but is not limited to a quadrangular prism, and may be a cylindrical cylinder or a polygonal cylinder other than a quadrangular prism. .

10 Circuit board 11 One side of circuit wiring 20 Aluminum electrolytic capacitor 30 Fixed case (heater resistance)
31 1st fixed terminal 32 2nd fixed terminal 35 Heater part 36 1st intensity | strength ensuring part 37 2nd intensity | strength ensuring part 40 Injector (fuel injection valve)
52 Microcomputer (control means)
61 Power supply voltage wiring (predetermined voltage wiring)
62 Reference voltage wiring 63 Circuit wiring

Claims (13)

A circuit wiring (63) having a plate shape having one surface (11) and including a predetermined voltage wiring (61) to which a predetermined voltage is applied and a reference voltage wiring (62) to which a reference voltage lower than the predetermined voltage is applied. ) Formed on the circuit board (10),
An aluminum electrolytic capacitor (20) mounted on one surface (11) of the circuit board (10) and electrically connected on a path between the predetermined voltage wiring (61) and the reference voltage wiring (62). ) And
By charging the aluminum electrolytic capacitor (20) based on the predetermined voltage, a terminal of the aluminum electrolytic capacitor (20) opposite to the reference voltage wiring (62) side is higher than the predetermined voltage. A booster for generating a voltage,
The cylindrical shape surrounding the aluminum electrolytic capacitor (20) is electrically connected to the circuit wiring (63) and fixed to the circuit board (10) on the one surface (11) side of the cylindrical shape. The first fixed terminal (31) and the second fixed terminal (32), and the aluminum is generated by generating heat by a current flowing through the path from the first fixed terminal (31) to the second fixed terminal (32). A booster comprising a fixed case (30) for heating the electrolytic capacitor (20). The fixed case (30) includes a plate-like first strength securing part (36) provided with the first fixed terminal (31) and a plate-like second provided with the second fixed terminal (32). A strength securing part (37) and a meandering plate-like heater part (35) meandering in the same plane;
One end portion (35a) of the heater portion (35) is connected to the opposite side of the first strength securing portion (36) to the side on which the first fixed terminal (31) is provided, The other end part (35b) of the heater part (35) is connected to the side opposite to the side where the second fixed terminal (32) is provided in the two strength securing part (37),
One end portion (36a) different from the side where the first fixed terminal (31) is provided in the first strength securing portion (36) and the side where the one end portion (35a) of the heater portion (35) is connected. And one end of the second strength securing portion (37) that is different from the side on which the second fixed terminal (32) is provided and the side to which the other end (35b) of the heater (35) is connected. (37a) are spaced apart from each other,
A plate-like member constituted by the first strength securing portion (36), the second strength securing portion (37), and the heater portion (35) is the other end of the first strength securing portion (36). (36b) and the other end portion (37b) of the second strength securing portion (37) are deformed so as to be spaced apart and arranged in a cylindrical shape,
Current flows in the path of the first fixed terminal (31), the first strength securing part (36), the heater part (35), the second strength securing part (37), and the second fixed terminal (32). The boosting device according to claim 1, wherein the boosting device is configured to flow.   The said 1st fixed terminal (31) is connected to the terminal on the opposite side to the said reference voltage wiring (62) side among the said aluminum electrolytic capacitors (20), The Claim 1 or 2 characterized by the above-mentioned. The booster described.   The fixed case (30) is energized and controlled by a control means (52) having a temperature detection means for detecting the temperature of the aluminum electrolytic capacitor (20). 4. The booster according to claim 1, wherein energization control is performed by the control unit when the temperature detected by the temperature detection unit is equal to or lower than a reference temperature. 5. A switching element (69) that is electrically connected to a path between the second fixed terminal (32) and the reference voltage wiring (62) and is driven by the control means (52) is provided. ,
The fixed case (30) is driven by the control means (52) at a duty ratio corresponding to the temperature detected by the temperature detection means of the control means (52) by the switching element (69). The boosting device according to claim 4, wherein energization control is performed.   In the fixed case (30), a predetermined time elapses after the control means (52) determines that the temperature detected by the temperature detection means of the control means (52) is equal to or lower than the reference temperature. The boosting device according to claim 4 or 5, wherein energization control is forcibly performed by the control means (52). The predetermined voltage is a power supply voltage generated by a power supply, and the aluminum electrolytic capacitor (20) is charged based on the power supply voltage,
The aluminum electrolytic capacitor (20) is discharged as drive power of the actuator to the actuator for opening the fuel injection valve (40) every time the fuel injection timing to the internal combustion engine arrives. The booster according to any one of claims 1 to 6, wherein In a circuit wiring (63) including a predetermined voltage wiring (61) to which a predetermined voltage is applied and a reference voltage wiring (62) to which a reference voltage lower than the predetermined voltage is applied, the predetermined voltage wiring (61) and the An aluminum electrolytic capacitor (20) electrically connected on a path between the reference voltage wiring (62) and
By charging the aluminum electrolytic capacitor (20) based on the predetermined voltage, a terminal of the aluminum electrolytic capacitor (20) opposite to the reference voltage wiring (62) side is higher than the predetermined voltage. A booster circuit for generating a voltage,
A first terminal (31) and a second terminal (32), wherein the first terminal (31) is electrically connected to the circuit wiring (63), and the first terminal (31) to the second terminal A heater resistor (30) for heating the aluminum electrolytic capacitor (20) by generating heat due to the current flowing in (32);
By being electrically connected on the path between the second terminal (32) of the heater resistor (30) and the reference voltage wiring (62) and being driven by the control means (52), And a switching element (69) for energizing the heater resistor (30).   The booster according to claim 8, wherein the first terminal (31) is connected to a terminal of the aluminum electrolytic capacitor (20) opposite to the reference voltage wiring (62) side. circuit.   The switching element (69) is driven by the control means (52) when the temperature of the aluminum electrolytic capacitor (20) detected by the temperature detection means provided in the control means (52) is below a reference temperature. 10. The booster circuit according to claim 8 or 9, wherein:   The switching element (69) is driven by the control means (52) at a duty ratio corresponding to the temperature of the aluminum electrolytic capacitor (20) detected by the temperature detection means of the control means (52). The step-up circuit according to claim 10.   In the switching element (69), the control means (52) determines that the temperature of the aluminum electrolytic capacitor (20) detected by the temperature detection means of the control means (52) is equal to or lower than the reference temperature. 12. The booster circuit according to claim 10, wherein the booster circuit is forcibly driven by the control means (52) until a predetermined time elapses. The predetermined voltage is a power supply voltage generated by a power supply, and the aluminum electrolytic capacitor (20) is charged based on the power supply voltage,
The aluminum electrolytic capacitor (20) is discharged as drive power of the actuator to the actuator for opening the fuel injection valve (40) every time the fuel injection timing to the internal combustion engine arrives. The step-up circuit according to claim 8, wherein

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