WO2020065923A1

WO2020065923A1 - Electrical load control device for vehicle

Info

Publication number: WO2020065923A1
Application number: PCT/JP2018/036291
Authority: WO
Inventors: 明彦山下
Original assignee: 本田技研工業株式会社
Priority date: 2018-09-28
Filing date: 2018-09-28
Publication date: 2020-04-02
Also published as: JP7061200B2; JPWO2020065923A1

Abstract

Provided is an electrical load control device for vehicles, which is able to reduce noise caused by current interruption. An electrical load control device 10-1 for vehicles is provided with: a vehicle electrical load 3 that includes an inductive load 31 and that is intermittently energized and operated; a first switch SW 1 that receives a mechanical on/off input operation as an operation input to the vehicle electrical load 3; and a second switch NF that is disposed between the first switch SW 1 and the vehicle electrical load 3 and that drives the vehicle electrical load 3 in accordance with the on/off state of the first switch SW 1, the electrical load control device being characterized in that the first switch SW 1 and the vehicle electrical load 3 are respectively connected to a control terminal G1 and a drive terminal S1 of the second switch NF, and the second switch NF and the vehicle electrical load 3 are connected in series.

Description

Electric load control device for vehicles

The present invention relates to a vehicle electric load control device capable of reducing noise caused by current interruption.

ノイズ There are various noise suppression technologies for in-vehicle devices. For example, in Patent Document 1, a microcomputer and an IC that constitute an electronic control unit in order to prevent the electronic control unit from malfunctioning due to noise generated by a direction indicator (turn signal lamp) or the like to be controlled by the electronic control unit And a method of switching the operating voltage for the DRAM.

Specifically, in Patent Literature 1, the lighting operation and the turning-off operation of the direction indicator and the like are defined in advance as a noise generating operation, and the operating voltage of the electronic control unit is changed from a low voltage to a high voltage before the time of the noise generating operation. Voltage, and after the time of the noise generation operation, the operation voltage of the electronic control unit is switched from the high voltage to the low voltage, so that the electronic control unit is in a high voltage operation state during the noise generation operation. The electronic control unit is prevented from malfunctioning due to noise.

JP 2010-284020 A

However, in the conventional technique such as the technique of Patent Document 1, there is a problem that the noise itself cannot be reduced.

For example, in a vehicle electric load controlled by intermittent energization such as a horn, a large amount of drive current remains at the moment when the drive is stopped by turning off the switch (in the case of a horn, the sound is stopped). Then, noise due to current interruption occurs. However, the related art cannot reduce such noise.

In view of the above-mentioned problems of the related art, an object of the present invention is to provide a vehicle electric load control device that can reduce noise caused by current interruption.

In order to achieve the above object, the present invention provides a vehicle electric load (3) including an inductive load (31) and performing an intermittent energizing operation, and a mechanical on-state as an operation input to the vehicle electric load (3). A first switch (SW1) for receiving an input operation of turning off, and a first switch (SW1) disposed between the first switch (SW1) and the vehicle electric load (3), and an on / off state of the first switch (SW1); A second switch (NF, THY, PF) for driving the vehicle electric load (3) according to the vehicle electric load controller (10, 10-1, 10-2, 10-3). , The control terminal (G1, G2, G3) and the drive terminal (S1, C2, S3) of the second switch (NF, THY, PF), respectively. ) Is connected, the second Switch (NF, THY, PF) and the vehicle electrical load (3) is a first being connected in series.

The second feature of the present invention is that the second switch (NF, THY, PF) is a thyristor (THY).

Further, according to the present invention, the drive terminals (S1, S3) of the second switch (NF, PF) are connected to the second switch (NF, PF) by turning off the first switch (SW1). When the control terminals (G1, G3) are turned off, a back electromotive force (V31) due to a current flowing through the vehicle electric load (3) is arranged. While the electromotive force (V31) is acting, the control terminals (G1, G3) of the second switch (NF, PF) are connected to the drive terminals (S1, S3) due to the presence of the back electromotive force (V31). The third feature is that the on-state is maintained based on ()).

The present invention has a fourth feature in that the second switch (NF, PF) is an N-type field effect transistor (NF).

第 Further, the present invention is characterized in that the vehicle electric load (3) is a horn.

The present invention accepts a vehicle electric load (3) including an inductive load (31) and intermittently energizing operation, and a mechanical ON / OFF input operation as an operation input to the vehicle electric load (3). A first switch (SW1), disposed between the first switch (SW1) and the electric load for the vehicle (3), and configured to switch the electric power for the vehicle in accordance with an on / off state of the first switch (SW1). A second switch (NF, THY, PF) for driving the load (3), wherein the second switch (NF) is provided in the vehicle electric load control device (10, 10-1, 10-2, 10-3). , THY, PF), the first switch (SW1) and the vehicle electric load (3) are connected to control terminals (G1, G2, G3) and drive terminals (S1, C2, S3), respectively. Two switches (NF, THY, P ) And the vehicle electrical load (3) is, according to a first feature of being connected in series,
Due to the circuit arrangement relationship between the second switch (NF, THY, PF) and the electric load for the vehicle (3), the operation of the circuit includes the instantaneous interruption of current when the first switch (SW1) is turned off. , It is possible to reduce noise.

According to a second feature of the present invention in that the second switch (NF, THY, PF) is a thyristor (THY),
As an element characteristic of the thyristor, even when the gate is turned off, the on-state is maintained until the main current becomes equal to or less than the holding current, so that the instantaneous interruption of the current itself when the first switch (SW1) is turned off is performed. , It is possible to reduce noise.

Further, according to the present invention, the drive terminals (S1, S3) of the second switch (NF, PF) are connected to the second switch (NF, PF) by turning off the first switch (SW1). When the control terminals (G1, G3) are turned off, a back electromotive force (V31) due to a current flowing through the vehicle electric load (3) is arranged. While the electromotive force (V31) is acting, the control terminals (G1, G3) of the second switch (NF, PF) are connected to the drive terminals (S1, S3) due to the presence of the back electromotive force (V31). According to the third feature of maintaining the ON state on the basis of
By maintaining the ON state, it is possible to reduce noise by preventing instantaneous interruption of current itself when the first switch (SW1) is turned off.

According to a fourth feature of the present invention in which the second switch (NF, PF) is an N-type field effect transistor (NF),
The back electromotive force (V31) when the first switch (SW1) is turned off acts on the source terminal of the N-type field effect transistor (NF), so that the ON state of the N-type field effect transistor (NF) is maintained. This makes it possible to reduce the noise by preventing the instantaneous interruption of the current itself when the first switch (SW1) is turned off.

According to a fifth feature of the present invention in which the vehicle electric load (3) is a horn,
As an operation for the horn, noise can be reduced by preventing instantaneous interruption of current itself when the first switch (SW1) is turned off.

1 is a schematic diagram showing an example of a wiring relationship in a motorcycle to which a vehicle electric load control device according to the present invention can be applied. 1 is a circuit configuration diagram of a vehicle electric load control device according to a first embodiment. It is a typical graph for explaining operation of the electric load control device for vehicles concerning a first embodiment. It is a circuit block diagram of the electric load control apparatus for vehicles which concerns on 2nd embodiment. It is a typical graph of the operation example of the electric load control device for vehicles concerning a second embodiment. It is a circuit block diagram of the electric load control apparatus for vehicles which concerns on 3rd embodiment.

FIG. 1 is a schematic diagram showing an example of a wiring relationship in a motorcycle to which the vehicle electric load control device of the present invention can be applied. The motorcycle 20 has, as a partial configuration thereof, a horn 3 which is an example of an electric load for a vehicle, and a button or the like configured to turn on / off a sound of the horn 3 when an occupant performs an on / off operation. An ECU (engine control unit) that includes one switch SW1, a general computer configuration such as a CPU (central processing unit) and a memory (not shown), a boost circuit, and the like, and performs various controls of the motorcycle 20. 1 and a meter 5 for performing various displays regarding the state of the motorcycle 20 such as the vehicle speed.

The meter 5 is configured to include a CPU for controlling display of the meter 5 itself, a memory (not shown), and the like, and the CPU for the meter 5 serially communicates with the ECU 1 via a wiring L5. The wiring L5 may be composed of a plurality. Further, the first switch SW1 and the horn 3 are connected through the wiring L1, so that the sound of the horn 3 can be controlled by turning on / off the first switch SW1. The horn 3 and the ECU 1 are connected through a wiring L3, so that the ECU 1 can monitor the state of the horn 3 (e.g., a current-carrying state).

Here, as schematically shown in FIG. 1, since at least a part of the wirings L1 and L3 and the wiring L5 are arranged close to each other, the blow of the horn 3 by the operation of the first switch SW1 is performed. When noise appears on the wiring L3 through which the horn DC flows due to the control, the influence of the noise also appears on the adjacent wiring L5 and the like. According to the electric load control device for a vehicle of the present invention, among the noises that appear with the sounding control of the horn 3, it is possible to reduce the noise that appears particularly on the wiring L3 when the horn 3 switches from on to off, and therefore The effect of noise on the parallel wiring L5 and the like can be reduced. In this way, even when the sound control of the horn 3 is switched from on to off, it is possible to normally continue communication on the wiring L5 and the like without being affected by noise.

Hereinafter, the vehicle electric load control device 10-1 according to the first embodiment with reference to FIGS. 2 and 3 and the vehicle electric load control device according to the second embodiment with reference to FIGS. 4 and 5 will be described. The device 10-2 and the vehicle electric load control device 10-3 according to the third embodiment will be described with reference to FIG. The vehicle electric load control devices 10-1, 10-2, and 10-3 according to the respective embodiments respectively correspond to the vehicle electric load control device 10 shown in FIG.

FIG. 2 is a circuit configuration diagram of the electric load control device for a vehicle 10-1 according to the first embodiment. The vehicle electric load control device 10-1 has a first switch SW1, an N-type field effect transistor (N-channel FET) NF as a second switch element as a main configuration, and an ON / OFF control target thereof. A horn 3, which is an example of an electric load for a vehicle.

(1) The first switch SW1 is configured as a mechanical switch or the like, and receives a manual operation of the switch by an occupant and switches the on / off state. One end of the first switch SW1 is connected to the power supply VS11, and the other end is connected to the gate (gate terminal) G1 of the N-type field effect transistor NF. Here, a resistor R1 is connected to a point P1 between the other end of the first switch SW1 and the gate G1, and a side of the resistor R1 opposite to the point P1 is grounded to the ground GND.

The N-type field effect transistor NF is connected in series with the horn 3 and drives the horn 3. That is, the N-type field effect transistor NF has its drain (drain terminal) D1 connected to the power supply VS12 via the ECU 1 and its source (source terminal) S1 connected to the horn 3, so that the first switch SW1 is turned on. In this state, the horn 3 is driven (sounds) by the power supply VS12 when the gate G1 is on.

(4) The ECU 1 supplies power from the power supply VS12 to the N-type field effect transistor NF. Here, the voltage V [VS12] of the power supply VS12 and the voltage V [VS11] of the power supply VS11 are set such that the magnitude relationship between the voltages is V [VS12] <V [VS11]. With this setting, when the first switch SW1 is turned on, the voltage of the gate G1 (by the power supply VS11) becomes higher than the voltage of the source S1 (by the power supply VS12), so that N The field effect transistor NF can be turned on. Further, the ECU 1 has a current monitoring function, and monitors the current of the horn 3 (the current of the drain D1 or the current of the source S1 supplied by the ECU 1 itself). Further, the ECU 1 (separately from the first switch SW1) has a function of turning on and off the N-type field-effect transistor NF as a protection mechanism against excessive current, so that the current of the horn 3 being monitored is predetermined. If the value exceeds the predetermined value, the gate G1 is forcibly turned off even when the first switch SW1 is in the on state, thereby cutting off the current exceeding the predetermined value.

The horn 3 has one end connected to the source S1 of the N-type field-effect transistor NF and the other end grounded to the ground GND, so that the horn 3 is driven by the N-type field-effect transistor NF as described above and blows.

The horn 3 includes the coil 31, the horn internal contact 32, and the sounding unit 33, so that the horn 3 sounds as in the existing method of general horns. That is, (1) the coil 31 to be energized constitutes an electromagnet, and the coil 31 as the electromagnet energized draws the diaphragm of the sounding section 33 including a diaphragm or the like (not shown) provided with an iron piece. After that, the horn internal contact 32 configured to be pushed and opened by a diaphragm displaced by a certain distance or more from the start position opens, and the current is cut off. (2) After the current is cut off, the diaphragm returns to the original position by the elastic force, the horn internal contact 32 is closed again, and the coil 31 becomes an electromagnet. By repeating the above (1) and (2), the diaphragm vibrates and the horn 3 blows. The diaphragm or the like that constitutes the blowing unit 33 may be configured to collide with a member at the time of the vibration and emit an impact sound.

The horn 3 is operated by being intermittently energized by the intermittent opening and closing of the horn internal contact 32 as a mechanical contact, so that the horn 3 is turned on while the N-type field effect transistor NF as the second switch element is in the on state. 3 will continue sounding. In FIG. 2, the voltage V31 which is arranged and drawn along with the coil 31 is for schematically representing the back electromotive force V31 generated by the coil 31, and does not represent an actual power supply or the like. . This is the same in FIGS. 4 and 6 described later.

In the vehicle electric load control device 10-1 according to the first embodiment having the circuit configuration as shown in FIG. 2, the inside of the horn 3 connected to the output side of the N-type field effect transistor NF as the second switch element. The back electromotive force V31 is generated by the coil 31 of FIG. Therefore, the ground potential becomes higher than the source potential, and a potential difference occurs. Due to this potential difference, the current is not immediately cut off even when the first switch SW1 is cut off, and the current is gradually cut off as the potential difference decreases, so that the operation can be performed while suppressing the generation of noise. It is possible.

Here, with reference to FIG. 3, it will be described that the noise generation can be suppressed. FIG. 3 is a schematic graph for explaining the operation of the vehicle electric load control device 10-1 according to the first embodiment of FIG. The graph of FIG. 3 shows the time change of each voltage and current separately in (1) to (4) by taking common time in the horizontal axis direction. Specifically, in FIG. 3, (1) is a graph of the voltage V [D1] of the drain D1 of the N-type field effect transistor NF, (2) is a graph of the voltage V [G1] of the gate G1, (3) is a graph of the voltage V [S1] of the source S1, and (4) is a graph of the current I [S1] of the source S1 (that is, the horn current I [S1]). The reference position of each voltage / current (the position where the voltage or current becomes 0 V or 0 A) is as shown by a broken line in the figure.

In FIG. 3, before the time t1, the first switch SW1 is on and the horn 3 is sounding, and the behavior of each voltage and current when the first switch SW1 is turned off at the time t1 is shown as a graph. Have been. That is, before the time t1, the voltage V [D1] of the drain D1 in (1) maintains a high voltage, and the voltage V [G1] of the gate G1 in (2) is a high voltage (voltage by the power supply VS11) when turned on. ), The horn current I [S1] of (4) shows the behavior of intermittent energization due to the intermittent opening and closing of the horn internal contact 32 as the current when the horn 3 blows, and the voltage V of the source S1 of (3) [S1] shows a behavior that slightly fluctuates on the high voltage side with the behavior of the horn current I [S1] in (4).

(3) In FIG. 3, the behavior after the first switch SW1 is turned off at the time t1 is as follows. First, the voltage V [D1] of the drain D1 in (1) does not change while maintaining the high voltage, and the voltage V [G1] of the gate G1 in (2) changes from the high voltage by turning off the first switch SW1. Changes steeply to the voltage of ground GND of 0V.

In other words, in FIG. 3, the horn current I [S1] at (4) at OFF time t1 is not zero but has a constant magnitude (corresponding to a state in which the horn internal contact 32 is closed). Here, as described above, the back electromotive force V31 by the coil 31 is generated. The generated back electromotive force appears as the voltage V [S1] of the source S1 in (3) after time t1, and is drawn to a negative potential lower than ground.

In this manner, after the time t1 at which the source S1 is turned off, the N-type field effect transistor NF gradually adapts to a transitional change until the voltage V [S1] of the source S1 returns from the negative potential to 0 V of the ground GND. At the same time, and the occurrence of noise is suppressed. The behavior that the noise generation is suppressed by gradually changing to the off state is represented as the behavior from time t1 to time t2 (time t2 when the off state is reached) in (3) and (4) of FIG. As shown, the horn current I [S1] of (4) gradually discharges to zero while the action by the back electromotive force remains at the voltage V [S1] of the source S1 of (3). It will be.

(4) The larger the back electromotive force is, the more difficult it is to change the N-type field-effect transistor NF to the off state due to its element characteristics, and thus the more slowly the state changes to the off state. As a result, it is possible to suppress noise generation, and since a high breakdown voltage is not required for the N-type field effect transistor NF, it is also possible to suppress costs by using a low breakdown voltage transistor.

Note that the example of FIG. 3 shows a case where the horn current I [S1] has a certain magnitude instead of zero at time t1 when the first switch SW1 is turned off by manual operation (when the horn internal contact 32 is in a closed state). ). Unlike the example of FIG. 3, when the horn internal contact 32 is open at the off time t1 and the horn current I [S1] is zero (when the first switch SW1 is turned off at such a timing t1). ), Since the current is zero in the first place, almost no noise is generated. Thus, even when the first switch SW1 is turned off at any timing t1 by manual operation by the occupant, that is, regardless of whether the horn current I [S1] at the off time t1 is zero or not, the noise is always present. Can be suppressed.

In addition, as a comparative example of the vehicle electric load control device 10-1 of the first embodiment of FIG. 2, assuming that the N-type field effect transistor NF (the first switch SW1 is connected to the gate G1) and the horn of FIG. In the case where a circuit configuration in which the arrangement relation with respect to 3 is reversed is adopted, that is, in the case where a circuit configuration in which the drain D1 of the N-type field effect transistor NF is connected to the horn 3 is adopted, noise as shown in FIG. The effect of suppression is not obtained, and a large noise is generated. In the case of this comparative example, when the voltage of the gate G1 is turned off, the voltage of the source S1 is also at the ground GND (the source S1 is always at the ground GND regardless of the on / off state of the gate G1). Since the effect of the generation of the electromotive force V31 cannot be obtained in the N-type field effect transistor NF, the instantaneous cutoff occurs and a large noise is generated according to the magnitude of the current at the time of OFF.

FIG. 4 is a circuit configuration diagram of the electric load control device for a vehicle 10-2 according to the second embodiment. As a schematic correspondence between the vehicle electric load control device 10-1 according to the first embodiment of FIG. 2 and the vehicle electric load control device 10-2 according to the second embodiment of FIG. In the second embodiment, the N-type field effect transistor NF as the second switch element is replaced by a thyristor THY as the second switch element in the second embodiment.

In FIG. 4, the vehicle electric load control device 10-2 includes a first switch SW1, a thyristor THY as a second switch element, and a vehicle electric load as an object whose on / off is controlled as main components. And a horn 3 as an example. In FIG. 4, components denoted by the same reference numerals as in FIG. 2, such as the first switch SW1 and the horn 3, have the same configuration as individual components as described with reference to FIG. For this reason, redundant description of the configuration as individual components will be omitted. This is the same for the vehicle electric load control device 10-3 according to the third embodiment shown in FIG.

一端 One end of the first switch SW1 is connected to the ECU1, and the other end is connected to the gate (gate terminal) G2 of the thyristor THY. When the first switch SW1 is turned on by manual operation by the occupant, a voltage and a current are applied from the ECU 1 to the gate G2 of the thyristor THY via the switch SW1 in the on state, and thereafter, the first operation is manually performed by the occupant. When one switch SW1 is switched from on to off, the voltage and current applied to the gate G2 are cut off. Here, a resistor R22 is arranged between the first switch SW1 and the gate G2, a resistor R21 is connected to a point P2 between the resistor R22 and the first switch SW1, and a point opposite to the point P2 of the resistor R21. One end is grounded to the ground GND.

Thyristor THY is connected in series with horn 3 and drives horn 3. That is, the thyristor THY has an anode (anode terminal) A2 connected to the power supply VS12 via the ECU 1 and a cathode (cathode terminal) C2 connected to the horn 3, so that the power supply when the thyristor THY is in the on state is turned on. The horn 3 is driven (blown) by the VS12.

(4) The ECU 1 supplies the voltage of the power supply VS12 to the thyristor THY. The ECU 1 has a current monitoring function, and monitors the current of the horn 3 (the current supplied to the anode A2 or the current supplied to the cathode C2 by the ECU 1 itself). Further, the ECU 1 has a current cutoff function as a protection mechanism against an excessive current, and when the monitored current becomes a predetermined value or more, the current (the current to the gate G2 or the current to the anode A2) ).

The horn 3 has one end connected to the cathode C2 of the thyristor THY and the other end grounded to the ground GND, so that the horn 3 is driven by the thyristor THY and blows as described above.

The vehicle electric load control device 10-2 according to the second embodiment having the circuit configuration as shown in FIG. 4 has the horn 3 that performs the element characteristics of the thyristor THY and the intermittent opening / closing operation connected in series. With the circuit configuration, even when the sound of the horn 3 is stopped by turning the first switch SW1 from on to off by manual operation by the occupant, it is possible to operate while suppressing the generation of noise.

That is, assuming that the moment when the current and the voltage applied to the gate G2 of the thyristor THY are cut off by switching the first switch SW1 from on to off is time t101, the thyristor THY is turned on due to its element characteristics. Rather than turning off immediately at time t101 (switching from the on-state to the off-state), it turns off only after the current stops after time t101 (the main current becomes equal to or less than the holding current). Therefore, it is assumed that the horn internal contact 32 of the horn 3 connected in series to the thyristor THY is in the closed state at the time t101 when the gate G2 is shut off. From time t101 to time t11 until the horn internal contact 32 is opened and the horn current stops at t11 (t11> t101), the thyristor THY maintains the ON state and the time t11 at which the horn current stops. Will be turned off for the first time.

That is, even if the horn internal contact 32 is closed and the horn current remains at the time t101 when the gate G2 is shut off, the thyristor THY does not immediately turn off, and the horn internal contact 32 is opened thereafter. At time t11 when the horn current stops, the thyristor THY turns off naturally for the first time. Then, after time t11 (unless the first switch SW1 is turned on again), the horn current is stopped and the current value becomes zero.

Thus, in the vehicle electric load control device 10-2 of the second embodiment, due to the element characteristics of the thyristor THY and the series connection of the horn 3 having the horn internal contact 32, the current is forcibly applied at the time t101 when the gate G2 is shut off. No interruptions occur. That is, in the vehicle electric load control device 10-2 of the second embodiment, noise due to back electromotive force due to forced cutoff of current cannot be generated in principle, and therefore, when the first switch SW1 is turned off. It is possible to suppress noise.

If the horn internal contact 32 is open at the time t101 when the gate G2 is shut off and the horn current is zero, the thyristor THY is immediately turned off at the time t101, but the horn current is also zero because the horn current is zero. No noise is generated. That is, in the second embodiment as well as in the first embodiment described above, the noise is suppressed regardless of the timing of the time t101 when the gate G2 is shut off.

FIG. 5 is a schematic graph showing that the vehicle electric load control device 10-2 of the second embodiment operates while suppressing noise as described above, and the horizontal axis represents the common time. The time changes of the respective voltages and currents are shown in the direction of the vertical axis, divided into (1) to (3). Specifically, FIG. 5 shows (1) a graph of the voltage V [G2] of the gate G2 of the thyristor THY, (2) a graph of the voltage V [C2] of the cathode C2, and (3) a graph of (3). 4 is a graph of a current I [C2] of a cathode C2 as a horn current. Further, FIG. 5 (4) shows an enlarged graph of the state near time t11 in (3). The reference position of each voltage / current (the position where the voltage or current becomes 0 V or 0 A) is as shown by a broken line in the figure.

In FIG. 5, from (1) to (3), the voltage is applied to the gate G2 by turning on the first switch SW1 at time t10, so that the thyristor THY is turned on and the horn 3 starts blowing. As described above, after the first switch SW1 is turned off at the time t101 shown enlarged in (4), the thyristor THY is turned off at the time t11 when the horn current stops, and the sounding of the horn 3 also stops. Behavior is shown. In the behavior shown, it can be seen how noise due to the OFF operation of the first switch SW1 at time t101 before time t11 is suppressed.

FIG. 6 is a circuit configuration diagram of a vehicle electric load control device 10-3 according to the third embodiment. The vehicle electric load control device 10-3 mainly includes a first switch SW1, a P-type field effect transistor (N-channel FET) PF as a second switch element, and a target whose ON / OFF is controlled. A horn 3, which is an example of an electric load for a vehicle.

The correspondence between the vehicle electric load control device 10-1 according to the first embodiment of FIG. 2 and the vehicle electric load control device 10-3 according to the third embodiment of FIG. The N-type field effect transistor NF as the switch element is replaced with a P-type field effect transistor PF as the second switch element in the third embodiment, and the N-type field effect transistor as the second switch element in the first embodiment. In the third embodiment, the relationship that the transistor NF was on the higher voltage side than the horn 3 is reversed, and the P-type field effect transistor PF as the second switch element is disposed on the lower voltage side than the horn 3 Have a relationship.

One end of the first switch SW1 is connected to the ground GND in the ECU1, the other end (point P3 side) is connected to the gate (gate terminal) G3 of the P-type field effect transistor PF, and the point P3 and the resistor R3 are connected. And connected to the power supply VS12.

The P-type field effect transistor PF is connected in series with the horn 3 and drives the horn 3. That is, the P-type field-effect transistor PF has its source (source terminal) S3 connected to the power supply VS12 via the horn 3 and the ECU 1, and its drain (drain terminal) D3 connected to the ground GND, so that the first switch The horn 3 is driven (sounds) by the power supply VS12 when the switch SW1 is on and the gate G3 is at the GND potential.

(4) The ECU 1 supplies the voltage of the power supply VS12 to the horn 3 and the P-type field effect transistor PF. Further, the ECU 1 has a current monitoring function, and monitors the current of the horn 3 (the current of the drain D3 or the current of the source S3 supplied by the ECU 1 itself). Further, the ECU 1 (separately from the first switch SW1) has a function of turning on and off the P-type field effect transistor PF as a protection mechanism against excessive current, so that the current of the monitored horn 3 is set to a predetermined value. If the value is equal to or more than the predetermined value, the gate G3 is forcibly turned off (high potential) even when the first switch SW1 is in the on state, thereby cutting off the current equal to or more than the predetermined value.

The horn 3 has one end connected to the source S3 of the P-type field effect transistor PF, and the other end connected to the power supply VS12 via the ECU 1, so that the horn 3 is driven by the P-type field effect transistor PF, and I do.

The vehicle electric load control device 10-3 according to the third embodiment having the circuit configuration as shown in FIG. 6 is configured such that the P-type field effect transistor PF has a lower voltage side (closer to ground GND) than the horn internal contact 32 of the horn 3. Side), the first switch SW1 is turned off from on by manual operation by the occupant.

The specific operation in which noise is suppressed when the first switch SW1 is turned off in the vehicle electric load control device 10-3 of the third embodiment is the vehicle electric load control device 10-1 of the first embodiment. Therefore, the detailed description thereof will be omitted, but the point is that when the horn current is not zero but exists at the moment when the first switch SW1 is turned off. Even if the gate G3 rises close to the voltage of the power supply VS12 because the high potential generated by the electromotive force V31 appears at the source S3, the potential of the source S3 becomes higher than the voltage of the power supply VS12, and as a result, the gate G3 is turned on. Is maintained, the discharge is gradually completed without instantaneous shutoff of the P-type field effect transistor PF.

補足 The following is a supplementary explanation of the present invention.

(1) The switch SW1 is configured as a mechanical switch or the like to receive a manual operation by an occupant, and one end of the switch SW1 is directly connected to the gates G1, G2, G3 to form the gates G1, G2. In the description above, G3 is switched on and off. As another embodiment to this, the following is also possible. The switch SW1 is configured as a mechanical switch or the like to receive a manual operation (on / off input state) by an occupant, and one end of the switch SW1 is not directly connected to the gates G1, G2, G3 but is connected to the ECU 1. By being connected, the on / off input state is received by the ECU 1, and then the ECU 1 further performs electrical control in accordance with the received on / off input state, whereby the gates G1, G2 , G3 may be configured to be switched on / off.

That is, the connection between one end of the switch SW1 and the gates G1, G2, G3 may be directly connected or may be indirectly connected via the ECU1.

(2) In the vehicle electric load control device 10-1 of the first embodiment and the vehicle electric load control device 10-2 of the second embodiment, when the horn 3 is not sounding, the internal contact 32 is closed. Since it is closed, its lower terminal (connected to ground GND) and its upper terminal also become ground GND. This makes it possible to prevent electrolytic corrosion.

Here, the ground GND to which one end (lower terminal) of the horn 3 is connected may be provided in the frame of the motorcycle 20 to adopt a one-side frame fastening structure. In addition, since even if moisture adheres, it is possible to prevent electric corrosion, it is possible to omit the provision of a waterproof structure at the contact of the horn 3. It is also possible to improve the maintainability and the like by arranging them so as to be exposed to the outside where they can adhere.

(3) The present invention is applicable not only to the horn 3 but also to any vehicle electric load having similar characteristics. That is, the second switch element (N-type field effect transistor NF, thyristor THY, P-type field effect transistor PF in each embodiment) is driven by a direct current under the ON / OFF operation of the first switch SW1, and the mechanical contact It is possible to apply the noise reduction method according to the present invention to any vehicle electric load having an inductive load such as the coil 31, which operates by being intermittently energized by intermittent closing by being constituted by is there.

(4) In the description with reference to FIG. 1, the wiring L5 as a communication line between the ECU 1 and the CPU of the meter 5 as a target whose noise influence is reduced is merely an example, and the noise of the wiring L3 around the horn 3 is only an example. The noise reduction effect according to the present invention can be obtained at any location that can be affected. Also, with reference to FIG. 1, a case has been described in which the vehicle electric load control device 10 of the present invention is mounted on a motorcycle 20 and applied, but the present invention is not limited to motorcycles but may be applied to any vehicle such as a four-wheel or three-wheel vehicle. The vehicle electric load control device 10 can be similarly applied.

10: Vehicle electric load control device, SW1: First switch, NF: N-type field effect transistor, THY: Thyristor, PF: P-type field effect transistor, 3: Horn (vehicle electric load), VS11, VS12: Power supply , GND… Ground, 1… ECU

Claims

A vehicle electric load (3) including an inductive load (31) and operating intermittently;
A first switch (SW1) that receives a mechanical ON / OFF input operation as an operation input to the vehicle electric load (3);
A second switch that is disposed between the first switch (SW1) and the vehicle electric load (3) and that drives the vehicle electric load (3) according to an on / off state of the first switch (SW1); In a vehicle electric load control device (10, 10-1, 10-2, 10-3) including two switches (NF, THY, PF),
The first switch (SW1) and the vehicle electric load (3) are respectively connected to control terminals (G1, G2, G3) and drive terminals (S1, C2, S3) of the second switch (NF, THY, PF). Is connected,
The electric load control device for a vehicle, wherein the second switch (NF, THY, PF) and the electric load for the vehicle (3) are connected in series.
The vehicle electric load control device according to claim 1, wherein the second switch (NF, THY, PF) is a thyristor (THY).
The drive terminals (S1, S3) of the second switch (NF, PF)
When the control terminal (G1, G3) of the second switch (NF, PF) is turned off by the first switch (SW1) being turned off, the vehicle electric load (3) is turned off. ) Are arranged so that a back electromotive force (V31) caused by a current flowing through
While the back electromotive force (V31) is acting, the control terminals (G1, G3) of the second switch (NF, PF) are connected to the drive terminal (S1) due to the presence of the back electromotive force (V31). The electric load control device for a vehicle according to claim 1, wherein the on-state is maintained on the basis of (S3).
4. The electric load control device for a vehicle according to claim 1, wherein the second switch (NF, PF) is an N-type field effect transistor (NF).
The vehicle electric load control device according to any one of claims 1 to 4, wherein the vehicle electric load (3) is a horn.