Load control device, igniter, engine ignition device, and vehicle

Abstract

A load control device according to one embodiment of the present invention includes: a switch element having a first main terminal, a second main terminal, and a control terminal that are connected to a load; a shunt resistor that is electrically connected between the second main terminal and a ground terminal and that detects a current flowing in the switch element; a switch control device configured to output a drive signal for driving the switch element to the control terminal, on the basis of a detection signal based on a detection result of the shunt resistor and a control signal from an external control device; and a capacitor electrically connected in parallel with the shunt resistor between the second main terminal and the ground terminal.

Description

Load control device, igniter, engine ignition device and vehicle

[0001] The present invention relates to a load control device, an igniter, an engine ignition device, and a vehicle.

[0002] An example of a conventional device including a switch element and a switch control circuit is an igniter. In the igniter, the switch element is connected to a primary coil of an ignition coil. The switch control circuit included in the igniter controls the switch element in response to an ignition signal. By controlling the switch element in this manner, the igniter controls the ignition coil (see Patent Document 1).

[0003] International Publication No. 2019 / 176501

[0004] [Summary] In an igniter, a switch element is connected to the primary coil of an ignition coil. Therefore, when the ignition coil is controlled by operating the switch element, noise can be injected from the primary coil side toward the switch element, and this noise can cause the switch control circuit to malfunction.

[0005] An object of one aspect of the present disclosure is to provide a load control device, an igniter, an engine ignition device, and a vehicle that are capable of reducing the influence of noise injected from the load side to be controlled.

[0006] The load control device according to the present disclosure includes a switch element having a first main terminal, a second main terminal, and a control terminal connected to a load, a shunt resistor connected between the second main terminal and a ground terminal for detecting a current flowing through the switch element, a switch control device that outputs a drive signal to the control terminal for driving the switch element based on a detection signal based on a detection result of the shunt resistor and a control signal from an external control device, and a capacitor connected in parallel with the shunt resistor between the second main terminal and the ground terminal.

[0007] FIG. 1 is a schematic diagram of a vehicle equipped with an engine ignition device. FIG. 2 is a schematic block diagram of an example of a switch control device. FIG. 3 is a plan view showing an example of the layout of the internal configuration of an igniter. FIG. 4 is a diagram for explaining the positional relationship between a lead frame and a switch element. FIG. 5 is a schematic diagram for explaining the reason why a switch element malfunctions. FIG. 6 is a schematic diagram showing the relationship between a gate signal, an emitter voltage, and a gate-emitter voltage in the igniter shown in FIG. 1. FIG. 7 is a diagram showing a modified connection configuration of a capacitor provided in the igniter. FIG. 8 is a plan view showing a first example layout of the internal configuration of an igniter according to the modified example shown in FIG. 7. FIG. 9 is a plan view showing a second example layout of the internal configuration of an igniter according to the modified example shown in FIG. 7. FIG. 10 is a diagram for explaining the positional relationship between a switch element and a capacitor. FIG. 11 is a diagram showing an example configuration of a vehicle.

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The following description of the preferred embodiments of the present disclosure will be given with reference to the accompanying drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and redundant description will be omitted.

[0009] Fig. 1 is a schematic diagram of a vehicle equipped with an engine ignition device. Specifically, Fig. 1 is a diagram showing a mechanism for driving a gasoline engine in a vehicle X. Although not shown in Fig. 1, the vehicle X also includes components other than those shown in Fig. 1.

[0010] As shown in Fig. 1, a vehicle X has, as mechanisms for driving a gasoline engine, an engine ignition device 1, a power source 2, and an engine control unit (external control device) 3. In the following description, the power source 2 is a car battery. Hereinafter, the engine control unit 3 will be referred to as an ECU (Engine Control Unit) 3.

[0011] The engine ignition device 1 operates by receiving power from a power source 2. The engine ignition device 1 is a device for igniting fuel in a gasoline engine in response to an ignition command signal IGT from an ECU 3. The ignition command signal IGT corresponds to a control signal from the ECU 3, which is an external control device. The fuel is a mixture of gasoline and air. The engine ignition device 1 includes an igniter 10, an ignition coil 4, and a spark plug 5.

[0012] The ignition coil 4 includes a primary coil 4 a and a secondary coil 4 b. First terminals of the primary coil 4 a and the secondary coil 4 b are electrically connected to the power source 2. A second terminal of the primary coil 4 a is electrically connected to an output terminal T4 of the igniter 10. A second terminal of the secondary coil 4 b is electrically connected to the spark plug 5.

[0013] The igniter 10 includes a switch control device 11 and a switch element 12. The igniter 10 controls the on / off of the switch element 12 based on an ignition instruction signal IGT supplied from the ECU 3.

[0014] When the switch element 12 is turned on based on the ignition command signal IGT, the battery voltage VBAT is applied from the power supply 2 to the primary coil 4a of the ignition coil 4, and the current I1 flowing through the primary coil 4a increases over time. When the switch element 12 is turned off based on the ignition command signal IGT, the current I1 through the primary coil 4a is cut off. At this time, a primary voltage proportional to the time differential of the current I1 is generated in the primary coil 4a. A secondary voltage equal to the primary voltage multiplied by the turns ratio is generated in the secondary coil 4b. This generated secondary voltage causes a spark in the spark plug 5.

[0015] 1, the igniter 10 has a high-potential power supply terminal T1 to which a battery voltage VBAT is supplied from the power supply 2, and an output terminal T4 electrically connected to the primary coil 4a of the ignition coil 4. The igniter 10 has a signal input terminal T3 electrically connected to the ECU 3, and a ground terminal T2 connected to ground. An ignition command signal IGT is input from the ECU 3 to the signal input terminal T3.

[0016] The igniter 10 includes a switch control device 11, a switch element 12, a resistor 13, a capacitor 14a, a capacitor 14b, a shunt resistor 15, and a capacitor 16. The igniter 10 is modularized and housed in a single package. The switch element 12 is configured as a single semiconductor chip including a transistor 121. In this example, the transistor 121 is an insulated gate bipolar transistor (IGBT). The terminals (C, G, E) of the transistor 121 may be described as terminals of the semiconductor chip, i.e., the switch element 12.

[0017] A first terminal of the resistor 13 is electrically connected to the high potential side power supply terminal T1. A second terminal of the resistor 13 is electrically connected to the high potential side power supply terminal P1 of the switch control device 11. The resistor 13 reduces, for example, a surge voltage superimposed on the battery voltage VBAT, thereby mitigating stress on the switch control device 11. The battery voltage VBAT is supplied to the switch control device 11 via the resistor 13 as the high potential side power supply voltage VDD.

[0018] The capacitor 14a is electrically connected between the high-potential side power supply terminal T1 and the ground terminal T2. The capacitor 14a, for example, reduces noise (e.g., spike noise) superimposed on the battery voltage VBAT and stabilizes the high-potential side power supply voltage VDD.

[0019] The capacitor 14b is electrically connected between the second terminal of the resistor 13 and the ground terminal T2. The capacitor 14b functions as, for example, a bypass capacitor that stabilizes the high-potential power supply voltage VDD.

[0020] The switch control device 11 has a high-potential power supply terminal P1 electrically connected to the second terminal of the resistor 13 and to which a high-potential power supply voltage VDD is input, and a ground terminal P2 electrically connected to the ground terminal T2. In the switch control device 11, the wiring that transmits the high-potential power supply voltage VDD from the high-potential power supply terminal P1 is referred to as a first voltage wiring L1, and the wiring that transmits the ground voltage (low-potential voltage) AGND from the ground terminal P2 is referred to as a ground wiring L2.

[0021] The switch control device 11 has a signal input terminal P3 electrically connected to the signal input terminal T3 and receiving the ignition instruction signal IGT, an output terminal P4 electrically connected to the switch element 12, and an input terminal P5 receiving the current flowing from the switch element 12 to the shunt resistor 15.

[0022] The switch control device 11 includes a reference voltage source 21, a regulator 22, a battery under voltage protection circuit (BUVP) 23, an over voltage protection circuit (BOVP) 24, a signal detection circuit 25, a delay circuit 26, an over current protection circuit 27, a drive circuit 28, and a current detection circuit 29.

[0023] The reference voltage source 21 generates a reference voltage Vref that serves as a reference for voltage comparison in the switch control device 11. The wiring that transmits the reference voltage Vref generated by the reference voltage source 21 is referred to as a second voltage wiring L3. The reference voltage source 21 is connected between the second voltage wiring L3 and the ground wiring L2. The reference voltage source 21 is, for example, a bandgap reference circuit.

[0024] The regulator 22 generates a drive voltage Vdd stabilized at a predetermined level based on a reference voltage Vref and a high-potential power supply voltage VDD. The wiring through which the drive voltage Vdd is transmitted is referred to as a fourth voltage wiring L4.

[0025] The low-voltage protection circuit 23 compares the high-potential-side power supply voltage VDD with a predetermined threshold voltage and outputs a detection signal K1 at a level corresponding to the comparison result. The threshold voltage of the low-voltage protection circuit 23 is set, for example, according to the lower limit voltage of the voltage range in which the switch control device 11 can operate.

[0026] The overvoltage protection circuit 24 compares the high-potential side power supply voltage VDD with a predetermined threshold voltage and outputs a detection signal K2 at a level corresponding to the comparison result. The threshold voltage of the overvoltage protection circuit 24 is set, for example, according to the upper limit voltage of the voltage range in which the switch control device 11 can operate.

[0027] The signal detection circuit 25 detects the ignition instruction signal IGT from the ECU 3 and outputs a reception signal S1.

[0028] The delay circuit 26 provides a predetermined delay to the received signal S1. The predetermined delay is set so that the time difference (delay) between the transition of the ignition command signal IGT and the discharge of the spark plug 5 is a predetermined value.

[0029] The overcurrent protection circuit 27 generates a control signal S3 to be supplied to the drive circuit 28 based on the output S2 from the delay circuit 26, the detection signal K1 from the low voltage protection circuit 23, and the detection signal K2 from the overvoltage protection circuit 24. The overcurrent protection circuit 27 generates the control signal S3 based on the output S2 so that the switch element 12 does not turn on for a predetermined current protection time.

[0030] The drive circuit 28 outputs a gate signal Sg that turns the switch element 12 on and off based on the control signal S3 and the detection signal CE from the current detection circuit 29 .

[0031] The current detection circuit 29 detects the emitter current Ie flowing from the emitter terminal (second main terminal) E of the switch element 12 to the shunt resistor 15. Since the emitter current Ie corresponds to the collector current Ic flowing through the switch element 12, the detection result of the emitter current Ie represents the state of the collector current Ic. The current detection circuit 29 generates a detection signal CE according to the detection result of the emitter current Ie. The detection signal CE is input to the drive circuit 28. The drive circuit 28 reduces the voltage level of the gate signal Sg based on the detection signal CE. For example, the drive circuit 28 reduces the voltage level of the gate signal Sg by adjusting the impedance on the switch element 12 side as viewed from the drive circuit 28 in response to the detection signal CE. This limits the collector current Ic to an upper limit value or less. Therefore, the current detection circuit 29 also functions as an overcurrent protection circuit.

[0032] 2 is a schematic block diagram of an example of the switch control device 11. An example of the signal detection circuit 25, the drive circuit 28, and the current detection circuit 29 will be described with reference to FIG.

[0033] An example of the signal detection circuit 25 includes a filter circuit 251 and a comparison circuit 252. The filter circuit 251 receives the ignition instruction signal IGT from the signal input terminal P3. The filter circuit 251 is a circuit for removing noise superimposed on the ignition instruction signal IGT. The filter circuit 251 is, for example, an RC filter circuit configured with a resistor and a capacitor. The comparison circuit 252 receives the output from the filter circuit 251 (the ignition instruction signal IGT from which noise has been removed) and a reference voltage Vref. The comparison circuit 252 compares the output from the filter circuit 251 with the reference voltage Vref to generate a reception signal S1.

[0034] An example of the drive circuit 28 includes transistors 281 and 282 connected in series between the fourth voltage wiring L4 and the ground wiring L2. The transistor 281 is, for example, a PMOSFET (P-channel Metal Oxide Semiconductor Field Effect Transistor), and the transistor 282 is, for example, an NMOSFET (N-channel MOSFET). A resistor 283 is disposed between the transistor 281 and a node N2 between the transistors 281 and 282. A resistor 284 is disposed between the transistor 282 and the node N2. The node N2 is electrically connected to the output terminal P4. The drive circuit 28 generates the gate signal Sg by adjusting the voltage level of a signal obtained by turning the transistors 281 and 282 on and off in response to a control signal S3 from the overcurrent protection circuit 27, as necessary, based on the detection signal CE described above.

[0035] As described above, when the drive circuit 28 has transistors 281, 282 and resistors 283, 284 connected in series, the influence of noise coming in from the output terminal P4 can be reduced by lowering the on-resistance of the transistors 281, 282 and the resistance of the resistors 283, 284.

[0036] An example of the current detection circuit 29 includes a filter circuit 291 and a comparison circuit 292. The filter circuit 291 receives the emitter current Ie from the input terminal P5. The filter circuit 291 is a circuit for removing noise superimposed on the emitter current Ie. The filter circuit 291 is, for example, an RC filter circuit configured with a resistor and a capacitor. The comparison circuit 292 receives the output from the filter circuit 291 (a voltage corresponding to the emitter current Ie from which noise has been removed) and a reference voltage Vref. The comparison circuit 292 compares the output from the filter circuit 291 with the reference voltage Vref to generate a detection signal CE.

[0037] Returning to FIG. 1 , the igniter 10 will be further described. The switch element 12 includes a transistor 121. A collector terminal C of the switch element 12 is electrically connected to the output terminal T4. As a result, the collector terminal (first main terminal) C is electrically connected to the primary coil 4a of the ignition coil 4. An emitter terminal (second main terminal) E of the switch element 12 is electrically connected to the ground terminal T2 via a shunt resistor 15. A gate terminal G of the switch element 12 is electrically connected to the output terminal P4. A gate signal Sg is input to the gate terminal G.

[0038] The switch element 12 may have a first protection element provided between the gate and collector of the transistor 121 for the purpose of overvoltage protection. The first protection element includes, for example, a diode connected in anti-series between the gate and collector of the transistor 121. The diode is, for example, a Zener diode. The first protection element clamps an overvoltage (e.g., surge noise, etc.) between the gate and collector to a predetermined voltage.

[0039] For the purpose of overvoltage protection, the switch element 12 may have a second protection element provided between the gate and emitter of the transistor 121. The second protection element includes, for example, a diode connected in anti-series between the gate and emitter of the transistor 121. The diode is, for example, a Zener diode. The second protection element clamps an overvoltage (e.g., surge noise, etc.) between the gate and emitter to a predetermined voltage.

[0040] A first terminal 15a of the shunt resistor 15 is electrically connected to the emitter terminal E, and a second terminal 15b of the shunt resistor 15 is electrically connected to the ground terminal T2. The shunt resistor 15 is a resistor for detecting the state of the emitter current Ie (the collector current Ic of the switch element 12). The resistance value of the shunt resistor 15 is several mΩ to several tens of mΩ, for example, 5 mΩ.

[0041] Capacitor 16 is connected in parallel to shunt resistor 15 between emitter terminal E and ground terminal T2. Capacitor 16 is an element for mitigating the effects of noise that has flowed into igniter 10 from output terminal T4. The capacitance of capacitor 16 may be any value that corresponds to the frequency of the noise to be removed.

[0042] If the wiring between the first terminal 15a of the shunt resistor 15 and the emitter terminal E is referred to as wiring L5, the first terminal 16a of the capacitor 16 may be connected closer to the shunt resistor 15 than the node N1 on the wiring L5, or connected to the node N1, or may be connected closer to the emitter terminal E than the node N1.

[0043] An example of the layout of the internal configuration of the igniter 10 will now be described with reference to Fig. 3. Fig. 3 is a diagram corresponding to the configuration in which the first terminal 16a is connected to the node N1 or closer to the shunt resistor 15 relative to the node N1, as shown in Fig. 1. A configuration in which the first terminal 16a is connected to the emitter terminal E closer to the node N1 on the wiring L5 will be described later as a modified example.

[0044] 3 is a plan view showing an example of the layout of the internal configuration of the igniter 10. In FIG. 3, the sealing resin 41 is indicated by a two-dot chain line.

[0045] The igniter 10 includes a sealing resin 41 that seals a portion of the lead frame and the components of the igniter 10, and a plurality of lead frames F1, F2 (first lead frame), F3, and F4 (second lead frame) that protrude from the sealing resin 41. The sealing resin 41 is formed in a roughly rectangular parallelepiped shape. Each of the lead frames F1, F2, F3, and F4 protrudes from one side of the sealing resin 41.

[0046] The igniter 10 has lead frames F5 and F6 housed within a sealing resin 41. Each of the lead frames F1 to F6 can be made of a conductive metal, such as copper (Cu), a Cu alloy, nickel (Ni), a Ni alloy, or a 42 alloy. The lead frames F1 to F6 may be plated with Pd, Ag, or the like. The sealing resin 41 can be made of an insulating resin, such as epoxy resin.

[0047] The lead frames F1, F2, F3, and F4 have mounting portions B1, B2, B3, and B4, and lead portions T11, T21, T31, and T41 extending from the mounting portions B1, B2, B3, and B4. The lead portions T11, T21, T31, and T41 correspond to the high-potential power supply terminal T1, the ground terminal T2, the signal input terminal T3, and the output terminal T4 shown in Figure 1. Because the lead portion T21 corresponds to the ground terminal T2 as described above, the lead frame F2 is connected to ground.

[0048] A resistor 13 is connected between the mounting portion B1 of the lead frame F1 and the lead frame F5. The resistor 13 is connected to the mounting portion B1 and the lead frame F5 by Ag paste, solder or the like.

[0049] A capacitor 14a is connected between the mounting portion B1 of the lead frame F1 and the mounting portion B2 of the lead frame F2. The capacitor 14a is connected to the mounting portion B1 and the mounting portion B2 by Ag paste, solder, etc. The capacitor 14a is mounted closer to the leads T11 and T21 than the resistor 13.

[0050] A capacitor 14b is connected between the mounting portion B2 of the lead frame F2 and the lead frame F5. The capacitor 14b is connected to the mounting portion B2 and the lead frame F5 by Ag paste, solder, etc. The capacitor 14b is mounted on the opposite side of the resistor 13 from the capacitor 14a.

[0051] The switch control device 11 is mounted on the mounting portion B2 of the lead frame F2. The switch control device 11 is connected to the mounting portion B2 by Ag paste, solder, or the like. The switch control device 11 is an IC chip. Pads P11, P21, P31, P41, and P51 are exposed on the top surface of the switch control device 11. The pads P11, P21, P31, P41, and P51 correspond to the high-potential power supply terminal P1, the ground terminal P2, the signal input terminal P3, the output terminal P4, and the input terminal P5 shown in FIG. 1 .

[0052] A switch element 12 is mounted on the mounting portion B4 of the lead frame F4.

[0053] Here, the positional relationship between the switch element 12 and the lead frame F4 will be described with reference to FIG. 4. FIG. 4 is a schematic diagram for explaining the positional relationship between the switch element 12 and the lead frame F4. The switch element 12 has a collector electrode PC on its lower surface and a gate pad PG and an emitter pad PE on its upper surface. The gate pad PG and the emitter pad PE are exposed from the upper surface. The collector electrode PC, the gate pad PG, and the emitter pad PE correspond to the collector terminal C, the gate terminal G, and the emitter terminal E of the switch element 12 shown in FIG. 1.

[0054] The switch element 12 is mounted on the mounting portion B4 by fixing the collector electrode PC to the mounting portion B4. In this case, the gate pad PG and the emitter pad PE are located on the opposite side of the lead frame F4 from the switch element 12. The collector electrode PC is fixed to the mounting portion B4 by Ag paste, solder, or the like.

[0055] 3, pad P11 is connected to lead frame F5 by wire W1. Pad P21 is connected to mounting portion B2 of lead frame F2 by wire W2. Pad P31 is connected to mounting portion B3 of lead frame F3 by wire W3. Pad P41 is connected to gate pad PG of switch element 12 by wire W4. Pad P51 is connected to lead frame F6 by wire W5. Emitter pad PE of switch element 12 is connected to lead frame F6 by wire W6.

[0056] The mounting portion B2 of the lead frame F2 is connected to the lead frame F6 by a wire W7. The wire W7 is disposed on the opposite side of the switch control device 11 from the lead portion T21.

[0057] The wires W1, W2, W3, W4, W5, and W6 are, for example, aluminum wires, each having a diameter of, for example, 125 μm. The wire W7 is, for example, aluminum wire, each having a diameter of, for example, 250 μm. The resistance value of the wire W7 is several mΩ to several tens of mΩ, for example, 5 mΩ. The resistance component of this wire W7 functions as the shunt resistor 15 shown in FIG. 1 . The end of the wire W7 that serves as the shunt resistor 15, connected to the lead frame F6, corresponds to the first terminal 15a of the shunt resistor 15, and the end that connects to the lead frame F2 corresponds to the second terminal 15b of the shunt resistor 15.

[0058] A capacitor 16 is further connected between the mounting portion B2 of the lead frame F2 and the lead frame F6. Therefore, the capacitor 16 is connected in parallel to the wire W7 that functions as the shunt resistor 15. In the capacitor 16, the connection portion with the lead frame F6 is a first terminal 16a, and the connection portion with the lead frame F2 is a second terminal 16b. The capacitor 16 is connected to the mounting portion B2 and the lead frame F6 by Ag paste, solder, or the like. The capacitor 16 is disposed closer to the wire W7 than the switch control device 11. The capacitor 16 is disposed parallel to the wire W7.

[0059] In the above configuration, the emitter pad PE is connected to the lead frame F2 via the wire W6, the lead frame F6, and the wire W7. The lead portion T21 of the lead frame F2 corresponds to the ground terminal T2. Therefore, the emitter pad PE is electrically connected to the lead portion T21 (ground terminal T2) via the wire W6, the lead frame F6, and the wire W7 (shunt resistor 15). Because the pad P51 is connected to the lead frame F6 via the wire W5, the lead frame F6 corresponds to the node N1 shown in FIG. 1. The capacitor 16 and the wire W7 connect the lead frames F2 and F6. Therefore, if the lead frame F6 is considered to be the node N1, in the configuration shown in FIG. 3, the first terminal 16a of the capacitor 16 is connected to the node N1.

[0060] 3, when the connection ends of wires W5 and W6 with lead frame F6 are close to each other but are distant from capacitor 16, the region where the connection ends of wires W5 and W6 with lead frame F6 are gathered can also be regarded as node N1. In this case, capacitor 16 is connected closer to wire W7 than wires W5 and W6, and therefore first terminal 16a of capacitor 16 can be said to be connected closer to wire W7 than node N1.

[0061] In the engine ignition device 1 shown in FIG. 1, as described above, when the switch element 12 is turned on based on the ignition command signal IGT input from the ECU 3, the battery voltage VBAT is applied from the power supply 2 to the primary coil 4a of the ignition coil 4, and the current I1 flowing through the primary coil 4a increases over time. When the switch element 12 is turned off based on the ignition command signal IGT, the current I1 through the primary coil 4a is cut off. At this time, a primary voltage proportional to the time derivative of the current I1 is generated in the primary coil 4a. A secondary voltage equal to the primary voltage multiplied by the turns ratio is generated in the secondary coil 4b. This generated secondary voltage causes a spark in the spark plug 5.

[0062] When the engine ignition device 1 operates as described above, high-frequency noise may be superimposed on the current I1 flowing through the primary coil 4a due to the influence of parasitic capacitance contained in the ignition coil 4. In this case, the high-frequency noise is injected into the igniter 10 from the output terminal T4. In the igniter 10 shown in FIG. 1, the influence of the noise can be reduced by connecting a capacitor 16 in parallel with the shunt resistor 15 between the emitter terminal E and the ground terminal T2. This point will be described in detail.

[0063] First, the reason why the switch element 12 malfunctions due to noise being superimposed on the current I1 (collector current Ic) will be explained with reference to Fig. 5. Fig. 5 is a schematic diagram for explaining the reason why the switch element 12 malfunctions.

[0064] Here, it is assumed that the gate signal Sg input to the gate terminal G of the switch element 12 achieves a desired logic level. In Fig. 5, the logic level of the gate signal Sg is high from time t1 to time t2, and transitions to low at time t2. When the gate signal Sg is high, the switch element 12 is in the on state, and when the gate signal Sg is low, the switch element 12 is in the off state.

[0065] Parasitic capacitance exists between the gate and emitter of the switch element 12 (specifically, the transistor 121). Therefore, when noise is superimposed on the collector current Ic, the level of the emitter voltage Ve is modulated by the parasitic capacitance between the gate and emitter, as shown in Figure 5. In Figure 5, the wavy line indicates modulation due to noise.

[0066] When the emitter voltage Ve is modulated by noise in this way, the gate-emitter voltage Vge deviates from a desired level, which is indicated by a two-dot chain line in FIG.

[0067] For example, as shown in FIG. 5, even if the gate signal Sg is at a high level, there are cases where the voltage level of the gate-emitter voltage Vge drops from the desired level, as in the voltage level between time t1a and time t2 shown in FIG. 5, and even if the gate signal Sg is at a low level, there are cases where the voltage level of the gate-emitter voltage Vge increases from the desired level, as in the voltage level between time t2a and time t2b shown in FIG.

[0068] When the voltage level of the gate-emitter voltage Vge drops from the desired level, as in the voltage level between time t1a and time t2, the gate voltage Vg drops due to the influence of the emitter voltage Ve. As a result, the desired characteristics of the switch element 12 are not satisfied, and there is a risk of the switch element 12 malfunctioning. When the voltage level of the gate-emitter voltage Vge increases from the desired level, as in the voltage level between time t2a and time t2b, the gate voltage Vg increases due to the influence of the emitter voltage Ve. As a result, there is a risk of the switch element 12 malfunctioning and switching to the on state during a period when it should be in the off state.

[0069] In contrast, the igniter 10 shown in FIG. 1 has a capacitor 16 connected in parallel to the shunt resistor 15. This reduces the impedance on the line L5 side as viewed from the emitter terminal E, thereby reducing the noise level superimposed on the emitter voltage Ve, as shown in FIG. 6. FIG. 6 is a schematic diagram showing the relationship between the gate signal Sg, the emitter voltage Ve, and the gate-emitter voltage Vge when the igniter 10 including the capacitor 16 is operating. In FIG. 6, the logic level of the gate signal Sg is high from time t1 to time t2, and transitions to low at time t2. When the gate signal Sg is high, the switch element 12 is in an on state, and when the gate signal Sg is low, the switch element 12 is in an off state. The dashed line in FIG. 6 indicates the noise level in the case of FIG. 5. As described above, the reduction in noise level allows the gate-emitter voltage Vge to achieve a desired voltage level corresponding to the logic level of the gate signal Sg. As a result, malfunction of the switch element 12 can be prevented.

[0070] 1, in the configuration in which the igniter 10 includes the resistor 13 and the capacitors 14a and 14b, the circuit formed by the resistor 13 and the capacitors 14a and 14b functions as a high-frequency filter. Therefore, the resistor 13 and the capacitors 14a and 14b can mitigate the effects of noise injected from the power supply 2 via the high-potential side power supply terminal T1. As a result, malfunction of the switch element 12 can be further prevented.

[0071] 2, when the signal detection circuit 25 includes the filter circuit 251, the noise contained in the ignition instruction signal IGT can be reduced. When the igniter 10 includes the delay circuit 26, the influence of the noise contained in the ignition instruction signal IGT can be further reduced. As a result, the malfunction of the switch element 12 can be further prevented.

[0072] 2, when current detection circuit 29 includes filter circuit 291, it is possible to reduce the influence of noise propagating from input terminal P5 toward current detection circuit 29, among noises injected into igniter 10 from output terminal T4 shown in FIG. 1. As a result, malfunction of switch element 12 can be further prevented.

[0073] As shown in FIG. 2, when drive circuit 28 has transistors 281 and 282 connected in series and resistors 283 and 284, the influence of noise entering from output terminal P4 among the noise injected into igniter 10 from output terminal T4 shown in FIG. 1 can be reduced by lowering the on-resistance of transistors 281 and 282 and the resistance of resistors 283 and 284.

[0074] As described above, the capacitor 16 is connected in parallel to the shunt resistor 15 between the emitter terminal E and the ground terminal T2. In Fig. 1, as an example of the connection of the capacitor 16, the case where the first terminal 16a of the capacitor 16 is connected to the node N1 or is connected closer to the shunt resistor 15 than the node N1 has been described.

[0075] However, as described above, the first terminal 16a of the capacitor 16 may be connected closer to the emitter terminal E than the node N1, as shown in Fig. 7. For ease of explanation, the igniter 10 shown in Fig. 7 may also be referred to as an igniter 10A.

[0076] In the igniter 10A, the first terminal 16a of the capacitor 16 is connected closer to the emitter terminal E than the node N1, so the electrical length between the emitter terminal E and the first terminal 16a is short. This reduces the influence of the inductance component contained in the wiring L5 between the emitter terminal E and the shunt resistor 15. As a result, the influence of noise can be further reduced. Because the first terminal 16a is connected closer to the emitter terminal E than the node N1, noise superimposed on the emitter current Ie input to the current detection circuit 29 via the input terminal P5 can also be reduced.

[0077] (First Layout Example of the Internal Structure of Igniter 10A) Figure 8 is a plan view showing an example of the layout of the internal structure of igniter 10A. In Figure 8, sealing resin 41 is indicated by a two-dot chain line. For ease of explanation, igniter 10A (10) shown in Figure 8 may also be referred to as igniter 10A1. Elements that are the same as those in the layout example of igniter 10 shown in Figure 3 are given the same reference numerals, and duplicate explanations will be omitted as appropriate.

[0078] The igniter 10A1 includes a sealing resin 41 that seals a portion of the lead frame and the components of the igniter 10A1, and a plurality of lead frames F1, F2 (first lead frame), F3, and F4 (second lead frame) that protrude from the sealing resin 41. The sealing resin 41 is formed in a generally rectangular parallelepiped shape. Each of the lead frames F1 to F4 protrudes from one side of the sealing resin 41. In FIG. 8, the sealing resin 41 is indicated by a two-dot chain line.

[0079] The igniter 10A1 has lead frames F5, F7, and F8 housed within a sealing resin 41. Each of the lead frames F1 to F5, F7, and F8 can be made of a conductive metal such as copper (Cu), a Cu alloy, nickel (Ni), a Ni alloy, or a 42 alloy. The lead frames F1 to F5, F7, and F8 may be plated with Pd, Ag, or the like. The sealing resin 41 can be made of an insulating resin, such as epoxy resin.

[0080] The lead frames F1 to F4 have mounting portions B1 to B4 and lead portions T11, T21, T31, and T41 extending from the mounting portions B1 to B4. The lead portions T11, T21, T31, and T41 correspond to the terminals of the igniter 10 shown in Figure 1. The specific correspondence is the same as in the layout example of the igniter 10 shown in Figure 3.

[0081] A resistor 13 is connected between the mounting portion B1 of the lead frame F1 and the lead frame F5. A capacitor 14a is connected between the mounting portion B1 of the lead frame F1 and the mounting portion B2 of the lead frame F2. A capacitor 14b is connected between the mounting portion B2 of the lead frame F2 and the lead frame F5.

[0082] The mounting portion B2 of the lead frame F2 has mounted thereon a switch control device 11. The mounting portion B4 of the lead frame F4 has mounted thereon a switch element 12.

[0083] A gate pad PG and an emitter pad PE are exposed on the top surface of the switch element 12. The gate pad PG and the emitter pad PE correspond to the gate terminal G and the emitter terminal E shown in FIG. 1. Pads P11, P21, P31, P41, and P51 corresponding to the respective terminals shown in FIG. 1 are exposed on the top surface of the switch control device 11. The specific correspondence between the pads P11, P21, P31, P41, and P51 and the respective terminals shown in FIG. 1 is the same as in the layout example of the igniter 10 shown in FIG. 3.

[0084] Pad P11 is connected to lead frame F5 by wire W1. Pad P21 is connected to mounting portion B2 of lead frame F2 by wire W2. Pad P31 is connected to mounting portion B3 of lead frame F3 by wire W3. Pad P41 is connected to gate pad PG of switch element 12 by wire W4. Pad P51 is connected to lead frame F8 by wire W8.

[0085] The emitter pad PE of the switch element 12 is connected to the lead frame F7 via a wire W9, and is also connected to the lead frame F8 via a wire W10.

[0086] The mounting portion B2 of the lead frame F2 is connected to the lead frame F8 via a wire W7. The wire W7 is disposed on the opposite side of the switch control device 11 from the lead portion T21.

[0087] Wires W1, W2, W3, W4, W8, W9, and W10 are, for example, aluminum wires with a diameter of, for example, 125 μm. Wire W7 is, for example, aluminum wire with a diameter of, for example, 250 μm. The resistance value of wire W7 is several mΩ to several tens of mΩ, for example, 5 mΩ. The resistance component of wire W7 functions as shunt resistor 15 shown in FIG. 1, similar to the layout example of igniter 10 shown in FIG. 3.

[0088] A capacitor 16 is connected between the mounting portion B2 of the lead frame F2 and the lead frame F7. The capacitor 16 is connected to the mounting portion B2 and the lead frame F7 by Ag paste, solder, or the like. The capacitor 16 is disposed on the opposite side of the wire W7 from the switch control device 11. The capacitor 16 is disposed parallel to the wire W7.

[0089] In the above configuration, the emitter pad PE is connected to the lead frame F2 via the wire W10, the lead frame F8, and the wire W7. The lead frame F2 has a lead portion T21 corresponding to the ground terminal T2, so the emitter pad PE is electrically connected to the ground terminal T2 via the wire W7 (shunt resistor 15). The lead frame F8 is connected to the pad P51 via the wire W8, so the lead frame F8 corresponds to the node N1 shown in FIG. 1. The capacitor 16 is connected between the mounting portion B2 of the lead frame F2 and the lead frame F7, and the lead frame F7 is connected to the emitter pad PE via the wire W9. Therefore, in the first layout example of the igniter 10A1 (10A, 10) shown in FIG. 8, the first terminal 16a of the capacitor 16 is electrically connected closer to the emitter pad PE (emitter terminal E) than to the node N1.

[0090] (Second Layout Example of the Internal Structure of Igniter 10A) Figure 9 is a plan view showing a second layout example of the internal structure of igniter 10A. In Figure 9, sealing resin 41 is indicated by a two-dot chain line. For ease of explanation, igniter 10A (10) shown in Figure 9 may also be referred to as igniter 10A2. Elements that are the same as those in the layout example shown in Figure 3 are given the same reference numerals, and duplicate explanations will be omitted as appropriate.

[0091] The igniter 10A2 includes a sealing resin 41 that seals a portion of the lead frame and the components of the igniter 10A2, and a plurality of lead frames F1, F2 (first lead frame), F3, and F4 (second lead frame) that protrude from the sealing resin 41. The sealing resin 41 is formed in a roughly rectangular parallelepiped shape. Each of the lead frames F1 to F4 protrudes from one side of the sealing resin 41.

[0092] The igniter 10A2 has a lead frame F5 and a lead frame (third lead frame) F10 housed in a sealing resin 41. Each of the lead frames F1 to F5, F10 can be made of a conductive metal such as copper (Cu), a Cu alloy, nickel (Ni), a Ni alloy, or a 42 alloy. The lead frames F1 to F5, F10 may be plated with Pd, Ag, or the like.

[0093] The lead frames F1 to F4 have mounting portions B1 to B4 and lead portions T11, T21, T31, and T41 extending from the mounting portions B1 to B4. The lead portions T11, T21, T31, and T41 correspond to the respective terminals of the igniter 10 shown in Figure 1. The specific correspondence is the same as in the layout example shown in Figure 3.

[0094] A resistor 13 is connected between the mounting portion B1 of the lead frame F1 and the lead frame F5. A capacitor 14a is connected between the mounting portion B1 of the lead frame F1 and the mounting portion B2 of the lead frame F2. A capacitor 14b is connected between the mounting portion B2 of the lead frame F2 and the lead frame F5.

[0095] The mounting portion B2 of the lead frame F2 has mounted thereon a switch control device 11. The mounting portion B4 of the lead frame F4 has mounted thereon a switch element 12.

[0096] A gate pad PG and an emitter pad PE are exposed on the upper surface of the switch element 12. The gate pad PG and the emitter pad PE correspond to the gate terminal G and the emitter terminal E shown in Fig. 1. Pads P11, P21, P31, P41, and P51 corresponding to the respective terminals shown in Fig. 1 are exposed on the upper surface of the switch control device 11. The specific correspondence between the pads P11, P21, P31, P41, and P51 and the respective terminals shown in Fig. 1 is the same as in the layout example shown in Fig. 3.

[0097] Pad P11 is connected to lead frame F5 by wire W1. Pad P21 is connected to mounting portion B2 of lead frame F2 by wire W2. Pad P31 is connected to mounting portion B3 of lead frame F3 by wire W3. Pad P41 is connected to gate pad PG of switch element 12 by wire W4. Pad P51 is connected to lead frame F10 by wire W11. Emitter pad PE of switch element 12 is connected to lead frame F10 by wire W12.

[0098] The mounting portion B2 of the lead frame F2 is connected to the lead frame F10 via a wire W7. The wire W7 is disposed on the opposite side of the switch control device 11 from the lead portion T21.

[0099] The wires W1, W2, W3, W4, W11, and W12 are, for example, aluminum wires with a diameter of, for example, 125 μm. The wire W7 is, for example, aluminum wire with a diameter of, for example, 250 μm. The resistance value of the wire W7 is several mΩ to several tens of mΩ, for example, 5 mΩ. The resistance component of this wire W7 functions as the shunt resistor 15 shown in FIG. 1, similar to the layout example shown in FIG. 3.

[0100] The capacitor 16 is disposed on the emitter pad PE as shown in Figures 9 and 10. Figure 10 is a schematic diagram for explaining the positional relationship of the capacitor 16 with respect to the switch element 12. Figure 10 also shows lead frames F2, F4 and a wire W13. The capacitor 16 is fixed to the emitter pad PE with Ag paste, solder, or the like. The surface of the capacitor 16 that is fixed to the emitter pad PE corresponds to a first terminal 16a, and the surface opposite to the emitter pad PE corresponds to a second terminal 16b.

[0101] A second terminal 16b of the capacitor 16 is connected to the mounting portion B2 of the lead frame F2 by a wire W13. The wire W13 is, for example, an aluminum wire and has a diameter of, for example, 125 μm.

[0102] In the above configuration, the emitter pad PE is connected to the lead frame F2 via the wire W12, the lead frame F10, and the wire W7. The lead frame F2 has a lead portion T21 corresponding to the ground terminal T2, so the emitter pad PE is electrically connected to the ground terminal T2 via the wire W7 (shunt resistor 15). The lead frame F10 is connected to the pad P51 via the wire W11. Therefore, the lead frame F10 corresponds to the node N1 shown in FIG. 1. The capacitor 16 is mounted directly on the emitter pad PE. Therefore, the first terminal 16a of the capacitor 16 is connected closer to the emitter pad PE than the node N1.

[0103] 9, when the capacitor 16 is mounted on the emitter pad PE, there is no need for a wire connecting the first terminal 16a of the capacitor 16 to the emitter pad PE, which reduces the effects of the inductance component, resistance component, etc. contained in the wire connecting the first terminal 16a of the capacitor 16 to the emitter pad PE.

[0104] Next, a configuration example of a vehicle X on which the engine ignition device 1 according to the embodiment is mounted will be described. Fig. 11 is a diagram showing a configuration example of a vehicle on which the engine ignition device 1 according to the embodiment is mounted.

[0105] The vehicle X includes the power supply 2 and ECU 3 described above, an engine unit 51 with a generator, a high-power DC / DC converter 52, an inverter 53, a motor 54, a drive unit 55, a high-voltage battery 56, and a DC / DC converter 57. For convenience of illustration, the mounting positions of the components in Fig. 11 differ from the actual positions. The vehicle X shown in Fig. 11 is a so-called series hybrid vehicle.

[0106] The generator-equipped engine section 51 includes a generator, a dedicated power generation engine that rotates the generator, and the engine ignition device 1 according to the various embodiments described above. Since the energy conversion efficiency of the engine varies greatly depending on the timing of ignition, the ignition timing must be controlled by the ECU 3 in consideration of the rotation angle of the crank that converts the reciprocating motion of the piston in the cylinder into rotational motion and the required amount of power generation. For this reason, the engine ignition device 1 according to the embodiments is provided for each cylinder of the engine.

[0107] The high-power DC / DC converter 52 converts DC power generated by the generator of the generator-equipped engine unit 51 into high-voltage DC power. The high-power DC / DC converter 52 supplies the high-voltage DC power to the inverter 53 and the high-voltage battery 56. The high-power DC / DC converter 52 can supply discharge power discharged from the high-voltage battery 56 to the inverter 53. The high-power DC / DC converter 52 can also charge the high-voltage battery 56 with regenerative power supplied from the inverter 53 when the vehicle X is decelerating.

[0108] The inverter 53 receives DC power from the high-power DC / DC converter 52 and converts the received DC power into three-phase AC power.

[0109] The motor 54 has a shaft and rotates the shaft using three-phase AC power supplied from the inverter 53 .

[0110] The drive unit 55 transmits power generated by the rotation of the shaft of the motor 54 to the drive wheels of the vehicle X. In Fig. 11, the rear wheels of the vehicle X are the drive wheels, but the drive wheels are not limited to the rear wheels. In other words, the front wheels may be the drive wheels, or both the front and rear wheels may be the drive wheels.

[0111] The DC / DC converter 57 receives DC power from the high-power DC / DC converter 52 and converts the received DC power into low-voltage DC power. The power supply 2, which is a low-voltage battery, is charged with the low-voltage DC power output from the DC / DC converter 57. The discharge power discharged from the power supply 2 is supplied to the engine ignition device 1 according to the embodiment and the like.

[0112] The vehicle on which the engine ignition device 1 according to the embodiment is mounted is not limited to a hybrid vehicle such as the vehicle X shown in FIG. 11, but may be any vehicle equipped with an engine.

[0113] Although the embodiments and modifications according to the present disclosure have been described above, the present invention is not limited to the exemplified embodiments. The present invention is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0114] Although an igniter has been described as an example of a load control device, the load control device is not limited to an igniter. Therefore, the load to be controlled by the load control device is not limited to the primary coil of an ignition coil. The load control device may control, for example, a solenoid injection or a load switch.

[0115] Although an IGBT is exemplified as a transistor included in the switch element, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) may also be used as the transistor.

[0116] According to the load control device, igniter, engine ignition device, and vehicle described in the above embodiment and modified examples, it is possible to reduce the influence of noise injected from the load to be controlled.

[0117] The various embodiments and modifications described above may be combined as appropriate without departing from the spirit of the present invention.

[0118] Various embodiments of the present disclosure may be defined as the following supplementary notes: [Supplementary Note 1] (Embodiment, FIG. 1) A load control device (10) comprising: a switch element (12) having a first main terminal (G) connected to a load (4), and also having a second main terminal (E) and a control terminal (G), a shunt resistor (15) electrically connected between the second main terminal and a ground terminal (T2) for detecting a current flowing through the switch element, a switch control device (11) configured to output a drive signal (Sg) for driving the switch element to the control terminal based on a detection signal (CE) based on a detection result of the shunt resistor and a control signal (IGT) from an external control device (3), and a capacitor (16) electrically connected in parallel with the shunt resistor between the second main terminal and the ground terminal.

[0119] [Supplementary Note 2] (Embodiment, FIGS. 1 and 2) The load control device according to Supplementary Note 1, wherein the switch control device (11) comprises: an input terminal (P5) connected to a wiring (L5) connecting the second main terminal and the shunt resistor, and into which a current flowing from the second main terminal to the shunt resistor is input; a current detection circuit (29) configured to detect the current input to the input terminal as a current flowing in the switch element and output a detection signal; and a drive circuit (28) configured to generate the drive signal based on the detection signal output from the current detection circuit and the control signal, wherein the capacitor has a first terminal (16a) electrically connected to the second main terminal and a second terminal (16b) electrically connected to the ground terminal, and the first terminal is electrically connected to a node (N1) between the wiring and the input terminal, or closer to the shunt resistor, on the wiring (L5).

[0120] [Supplementary Note 3] (Variation, FIG. 7) The load control device according to Supplementary Note 1, wherein the switch control device (11) comprises: an input terminal (P5) connected to a wiring (L5) connecting the second main terminal and the shunt resistor, and into which a current flowing from the second main terminal to the shunt resistor is input; a current detection circuit (29) configured to detect the current input to the input terminal as a current flowing in the switch element and output a detection signal; and a drive circuit (28) configured to generate the drive signal based on the detection signal output from the current detection circuit and the control signal, wherein the capacitor (16) has a first terminal (16a) electrically connected to the second main terminal (E) and a second terminal (16b) electrically connected to the ground terminal, and the first terminal is electrically connected to the wiring (L5) closer to the second main terminal than a node (N1) between the wiring and the input terminal.

[0121] [Supplementary Note 4] (First layout example of components of an igniter according to a modified example, FIG. 8) The igniter includes a first lead frame (F2) on which the switch control device is mounted and which is electrically connected to ground, a second lead frame (F4) on which the switch element is mounted, a third lead frame (F8), and a fourth lead frame (F7), wherein the switch control device has an input terminal (corresponding to pad P51 in FIG. 8) to which a current flowing from the second main terminal to the shunt resistor is input, wherein the first main terminal (corresponding to collector electrode PC shown in FIG. 4) of the switch element is located opposite to the second main terminal (corresponding to emitter pad PE in FIG. 8), wherein the first main terminal is fixed to the second lead frame, thereby mounting the switch element on the second lead frame, wherein the first lead frame (F2) and the fourth lead frame (F7) are connected by the capacitor (16), and the first lead frame (F2) and the third lead frame (F8) are connected by the shunt resistor (W7), The load control device according to claim 1 or 3, wherein the third lead frame (F8) and the second main terminal are connected by a wire (W10), the fourth lead frame (F7) and the second main terminal are connected by a wire (W9), and the input terminal (P51) of the switch control device is connected to the third lead frame by a wire (W8).

[0122] [Supplementary Note 5] (Second layout example of components of an igniter according to a modified example, FIGS. 9 and 10) The igniter includes a first lead frame (F2) on which the switch control device (11) is mounted and which is electrically connected to ground, a second lead frame (F4) on which the switch element (12) is mounted, and a third lead frame (F10), wherein the switch control device has an input terminal (corresponding to pad P51 in FIG. 9) to which a current flowing from the second main terminal to the shunt resistor is input, wherein the first main terminal (corresponding to collector electrode PC shown in FIG. 10) of the switch element is located opposite to the second main terminal (corresponding to emitter pad PE in FIGS. 9 and 10), wherein the switch element (12) is mounted on the second lead frame by having the first main terminal fixed to the second lead frame, and wherein the first lead frame (F2) and the third lead frame (F10) are connected by the shunt resistor (W7), The load control device according to Supplementary Note 1 or Supplementary Note 3, wherein the capacitor (16) is mounted on the second main terminal (corresponding to the emitter pad PE in Figures 9 and 10) by fixing a first terminal (16a) of the capacitor to the second main terminal, a second terminal (16b) of the capacitor located opposite the first terminal (16a) is connected to the first lead frame (F2) by a wire (W13), the third lead frame (F10) and the second main terminal pad are connected by a wire (W12), and the input terminal of the switch control device (11) (corresponding to the pad P51 in Figure 9) is connected to the third lead frame (F10) by a wire (W11).

[0123] [Supplementary Note 6] (Embodiment, FIG. 1) An igniter comprising the load control device (10) according to any one of Supplementary Notes 1 to 5, wherein the load is an ignition coil (4), the first main terminal is connected to a primary coil (4a) of the ignition coil, and the control signal is an ignition instruction signal (IGT).

[0124] [Supplementary Note 7] (Embodiment, FIG. 1) An engine ignition device (1) comprising: an ignition coil (4); an igniter (10) according to Supplementary Note 6 connected to a primary coil (4a) of the ignition coil; and a spark plug (5) connected to a secondary coil (4b) of the ignition coil.

[0125] [Supplementary Note 8] (Vehicle shown in FIG. 11) A vehicle comprising: the engine ignition device (1) according to Supplementary Note 7; a power source (2) that supplies power to the engine ignition device; and an engine control unit (3) configured to control the engine ignition device.

[0126] [Supplementary Note 9] (Embodiment, FIGS. 1 and 2) The load control device according to Supplementary Note 1, wherein the switch control device (11) comprises: an input terminal (P5) connected to a wiring (L5) connecting the second main terminal and the shunt resistor, and into which a current flowing from the second main terminal to the shunt resistor is input; a current detection circuit (29) configured to detect the current input to the input terminal as a current flowing in the switch element and output a detection signal; and a drive circuit (28) configured to generate the drive signal based on the detection signal output from the current detection circuit and the control signal.

[0127] X... Vehicle 1... Engine ignition device 2... Power supply 3... Engine control unit, ECU (external control device) 4... Ignition coil 4a... Primary coil 4b... Secondary coil 5... Spark plug 10, 10A, 10A1,DESCRIPTION OF SYMBOLS 10A2...Igniter (load control device) 11...Switch control device 12...Switch element 121...Transistor C...Collector terminal (first main terminal) E...Emitter terminal (second main terminal) G...Gate terminal (control terminal) 13...Resistor 14a...Capacitor 14b...Capacitor 15...Shunt resistor 15a...First terminal 15b...Second terminal 16...Capacitor 16a...First terminal 16b...Second terminal 21...Reference voltage source 22...Regulator 23...Low voltage protection circuit 24...Overvoltage protection circuit 25...Signal detection circuit 251...Filter circuit 252...Comparator circuit 26...Delay circuit 27...Overcurrent protection circuit 28...Driver circuit 281...Transistor 282...Transistor 283...Resistor 284...Resistor 29...Current detection circuit 291...Filter circuit 292...Comparator circuit 41...Sealing resin 52...DC converter 53...Inverter 54...Motor 55...Driver 56...High-voltage battery 57...DC converter B1...Mounting portion B2...Mounting portion B3...Mounting portion B4...Mounting portion P1...High-potential power supply terminal P2...Ground terminal L1...First voltage wiring L2...Ground wiring P3...Signal input terminal P4...Output terminal P5...Input terminal L3...Second voltage wiring L4...Fourth voltage wiring L5...Wiring N2...Node N1...Node F1...Lead frame F2...Lead frame (first lead frame) F3...Lead frame F4...Lead frame (second lead frame) F5...Lead frame F6...Lead frame F7...Lead frame (fourth lead frame) F8...Lead frame (third lead frame) F10...Lead frame (third lead frame) T1...High-potential power supply terminal T2...Ground terminal T3...signal input terminal T4...output terminal T11...lead portion T21...lead portion T31...lead portion T41...lead portion P11...pad P21...pad P31...pad P41...pad P51...pad (input terminal) PC...collector electrode (first main terminal) PG...gate pad (control terminal) PE...emitter pad (second main terminal) W1...wire W2...wire W3...wire W4...wire W5...wire W6...wire W7...wire W8...wire W9...wire W10...wire W11...wire W12...wire W13...wire

Claims

1. A switch element having a first main terminal connected to a load, as well as a second main terminal and a control terminal, A shunt resistor is electrically connected between the second main terminal and the ground terminal, and is used to detect the current flowing through the switch element. A switch control device configured to output a drive signal to the control terminal for driving the switch element based on a detection signal based on the detection result of the shunt resistor and a control signal from an external control device, A capacitor electrically connected in parallel with the shunt resistor between the second main terminal and the ground terminal, Equipped with, Load control device.

2. The aforementioned switch control device is An input terminal connected to the wiring that connects the second main terminal and the shunt resistor, into which the current flowing from the second main terminal to the shunt resistor is input, A current detection circuit configured to detect the current input to the input terminal as the current flowing through the switch element and output a detection signal, A drive circuit configured to generate the drive signal based on the detection signal output from the current detection circuit and the control signal, Equipped with, The capacitor has a first terminal electrically connected to the second main terminal and a second terminal electrically connected to the ground terminal. The first terminal is electrically connected to the node between the wiring and the input terminal, or to the node, The load control device according to claim 1.

3. The aforementioned switch control device is An input terminal connected to the wiring that connects the second main terminal and the shunt resistor, into which the current flowing from the second main terminal to the shunt resistor is input, A current detection circuit configured to detect the current input to the input terminal as the current flowing through the switch element and output a detection signal, A drive circuit configured to generate the drive signal based on the detection signal output from the current detection circuit and the control signal, Equipped with, The capacitor has a first terminal electrically connected to the second main terminal and a second terminal electrically connected to the ground terminal. The first terminal is electrically connected in the wiring to the second main terminal, closer to the node between the wiring and the input terminal. The load control device according to claim 1.

4. The switch control device is mounted on a first lead frame that is electrically connected to ground, The second lead frame on which the aforementioned switch element is mounted, The third lead frame, The fourth lead frame, Equipped with, The switch control device has an input terminal to which the current flowing from the second main terminal to the shunt resistor is input, In the aforementioned switch element, the first main terminal is located opposite to the second main terminal. The switch element is mounted on the second lead frame by having the first main terminal fixed to the second lead frame. The first lead frame and the fourth lead frame are connected by the capacitor, The first lead frame and the third lead frame are connected by the shunt resistor. The third lead frame and the second main terminal are connected by a wire. The fourth lead frame and the second main terminal are connected by a wire. The input terminal of the switch control device is connected to the third lead frame by a wire. The load control device according to claim 1.

5. The switch control device is mounted on a first lead frame that is electrically connected to ground, The second lead frame on which the aforementioned switch element is mounted, The third lead frame, Equipped with, The switch control device has an input terminal to which the current flowing from the second main terminal to the shunt resistor is input, In the aforementioned switch element, the first main terminal is located opposite to the second main terminal. The switch element is mounted on the second lead frame by having the first main terminal fixed to the second lead frame. The first lead frame and the third lead frame are connected by the shunt resistor. The capacitor is mounted on the second main terminal by fixing its first terminal to the second main terminal. In the capacitor, the second terminal, which is located opposite to the first terminal, is connected to the first lead frame by a wire. The input terminal of the switch control device is connected to the third lead frame by a wire. The load control device according to claim 1.

6. A load control device according to any one of claims 1 to 5, The aforementioned load is an ignition coil. The first main terminal is connected to the primary coil of the ignition coil, The aforementioned control signal is an ignition instruction signal. Igniter.

7. Ignition coil and The igniter according to claim 6, which is connected to the primary coil of the ignition coil, The spark plug connected to the secondary coil of the ignition coil, Equipped with, Engine ignition system.

8. The engine ignition device according to claim 7, A power supply that provides power to the aforementioned engine ignition device, An engine control unit configured to control the engine ignition device, Equipped with, vehicle.