Vehicle surge protection device and vehicle irradiation device

Abstract

To provide a surge protection device for a vehicle which can reduce power loss in a surge protection circuit, and an irradiation device for a vehicle.SOLUTION: A surge protection device for a vehicle concerning an embodiment is electrically connected with an electronic component provided in the vehicle. The surge protection device for the vehicle is equipped with: a first surge protection circuit; and a control circuit provided on an input side of the first surge protection circuit to control a value of input voltage of the first surge protection circuit. The control circuit makes the value of the input voltage of the first surge protection circuit lower than the maximum rated voltage value of the electronic component and higher than an upper limit value of the input voltage in a normal state.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to a surge protection device for a vehicle and an irradiation device for a vehicle.

Background Art

[0002] Vehicles such as automobiles and railways are provided with electronic devices used for vehicle operation and irradiation devices equipped with light-emitting diodes and discharge lamps. In this case, the electronic devices for vehicles are provided with electronic components such as semiconductor elements and integrated circuits. The irradiation devices for vehicles are provided with electronic components such as light-emitting diodes. The irradiation devices for vehicles equipped with a discharge lamp are provided with a lighting circuit for lighting the discharge lamp. The lighting circuit is provided with electronic components such as semiconductor elements and integrated circuits. In addition, the electronic devices for vehicles and the irradiation devices for vehicles are electrically connected to a DC power supply provided in the vehicle.

[0003] Here, a surge voltage may be applied to the electronic devices for vehicles and the irradiation devices for vehicles. For example, when the power line is disconnected from the DC power supply for some reason, a load dump surge occurs. When a surge voltage is applied to the electronic devices for vehicles and the irradiation devices for vehicles, the electronic components provided therein may malfunction.

[0004] Therefore, a technique has been proposed in which a Zener diode is electrically connected between the power line and the ground line to clamp the surge voltage to a constant voltage. In addition, a technique has also been proposed in which a linear regulator is electrically connected to the subsequent stage of the Zener diode to clamp the surge voltage to an even lower voltage. If the surge voltage can be clamped to a low voltage, it is possible to suppress the failure of electronic components with a low maximum rated voltage provided in the electronic devices for vehicles and the irradiation devices for vehicles.

[0005] Here, for a surge protection circuit such as a linear regulator, a set voltage based on the allowable loss is determined in advance. In this case, if a surge protection circuit with a low set voltage is selected, the surge voltage applied to vehicle electronic devices or the like can be reduced. However, if a surge protection circuit with a low set voltage is selected, the power loss in the surge protection circuit increases.

[0006] Also, the voltage applied to vehicle electronic devices or the like varies, for example, in the range of 9V to 16V. Therefore, if a surge protection circuit with a low set voltage is selected, even when the input voltage in a normal state reaches the upper limit value (for example, 16V), the power loss in the surge protection circuit increases.

[0007] When the power loss in the surge protection circuit becomes larger than expected, for example, the temperature of an output driver (for example, a transistor) provided in the surge protection circuit may become too high. Therefore, the development of a technology capable of reducing the power loss in the surge protection circuit has been desired.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] The problem to be solved by the present invention is to provide a vehicle surge protection device and a vehicle irradiation device capable of reducing the power loss in the surge protection circuit.

Means for Solving the Problems

[0010] The vehicle surge protection device according to the embodiment is a vehicle surge protection device electrically connected to an electronic component provided in a vehicle. The vehicle surge protection device includes a first surge protection circuit; and a control circuit provided on the input side of the first surge protection circuit to control the value of the input voltage of the first surge protection circuit. The control circuit makes the value of the input voltage of the first surge protection circuit lower than the maximum rated voltage value of the electronic component and higher than the upper limit value of the input voltage in a normal state.

Effects of the Invention

[0011] According to an embodiment of the present invention, it is possible to provide a vehicle surge protection device and a vehicle irradiation device that can reduce power loss in a surge protection circuit.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments will be exemplified with reference to the drawings. In each drawing, the same reference numerals are given to the same components, and detailed descriptions thereof are omitted as appropriate. The vehicle surge protection device according to the present embodiment is electrically connected, for example, between a DC power supply (for example, a battery) provided in a vehicle such as an automobile or a railway, and vehicle electronic devices, vehicle irradiation devices, and the like.

[0014] Here, as an example, the case where the vehicle surge protection device is electrically connected between the DC power supply and the irradiation module (in the case of a vehicle irradiation device) will be described. However, the same applies to the case where the vehicle surge protection device is electrically connected between the DC power supply and a vehicle electronic device (for example, an electronic device used for vehicle operation).

[0015] FIG. 1 is a circuit diagram for exemplifying a vehicle irradiation device 100 according to the present embodiment. As shown in FIG. 1, the vehicle irradiation device 100 is provided with, for example, a vehicle surge protection device 1 and an irradiation module 50 (60).

[0016] The vehicle irradiation device 100 is electrically connected to a DC power supply 200. The DC power supply 200 is, for example, a battery mounted on a vehicle such as an automobile. The rated voltage of the DC power supply 200 is about 13.5 V DC. Therefore, the input voltage of the irradiation module 50 (60) is about 13.5 V. However, in reality, due to factors such as battery voltage drop, alternator operation, and circuit influence, the voltage from the DC power supply 200 (the input voltage of the irradiation module 50 (60)) fluctuates in the range of, for example, 9 V to 16 V.

[0017] Here, a surge voltage may be applied to the irradiation module 50 (60). For example, when the power line is disconnected from the DC power supply 200 for some reason, a load dump surge occurs. When a surge voltage is applied to the irradiation module 50 (60), there is a risk that electronic components such as a light emitting element 53, a circuit element 54, and a switching element 65b provided in the irradiation module 50 (60) may malfunction.

[0018] Therefore, the vehicle irradiation device 100 is provided with a vehicle surge protection device 1. The vehicle surge protection device 1 is electrically connected between the irradiation module 50 (60) and the DC power supply 200. Hereinafter, as an example, a vehicle surge protection device 1 having a Zener diode 2 (corresponding to an example of a second surge protection circuit) and a linear regulator 3 (corresponding to an example of a first surge protection circuit) will be described.

[0019] The vehicle surge protection device 1 includes, for example, a Zener diode 2, a linear regulator 3, a capacitor 4, and a control circuit 8.

[0020] The Zener diode 2 is provided on the input side of the control circuit 8. The Zener diode 2 is electrically connected between the power line 201 and the ground line 202. If the Zener diode 2 is provided, the surge voltage can be clamped to a low voltage, so that electronic components such as light-emitting elements provided in the irradiation module 50(60) can be protected.

[0021] The linear regulator 3 is provided, for example, with an output driver, a reference voltage source, a feedback resistor, and a comparator. The output driver is, for example, a MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor). The reference voltage source, the feedback resistor, and the comparator constitute a circuit for controlling the output driver. For example, the comparator controls the output driver based on the difference between the output voltage and the reference voltage to output a constant voltage from the linear regulator 3.

[0022] The linear regulator 3 is provided between the Zener diode 2 and the irradiation module 50(60). The linear regulator 3 is electrically connected between the power line 201 and the ground line 202. Electronic components with a low maximum rated voltage may be provided in the irradiation module 50(60). Therefore, the protection of the electronic components may be insufficient with only the Zener diode 2. Therefore, the vehicle surge protection device 1 is provided with the linear regulator 3. If the linear regulator 3 is provided, the input voltage of the irradiation module 50(60) can be made lower than the set voltage of the linear regulator 3. Therefore, the surge voltage can be clamped to an even lower voltage, so that electronic components with a low maximum rated voltage can be protected.

[0023] FIG. 2 is a schematic graph for exemplifying voltage clamping by the Zener diode 2 and the linear regulator 3. As shown in FIG. 2, the surge voltage V1 is clamped to the clamping voltage V2 by the Zener diode 2, and is clamped to the clamping voltage V3 lower than the clamping voltage V2 by the linear regulator 3. Therefore, even if the irradiation module 50(60) is provided with electronic components having a low maximum rated voltage, the protection of the electronic components can be achieved.

[0024] As shown in FIG. 1, the capacitor 4 is electrically connected between the linear regulator 3 and the irradiation module 50(60). Since the surge voltage often becomes a steep voltage fluctuation faster than the response speed of the linear regulator 3, the output voltage of the linear regulator 3 may drop. When the output voltage of the linear regulator 3 drops, the light irradiated from the irradiation module 50(60) may flicker. Therefore, the capacitor 4 supplies current to the irradiation module 50(60) instead of the linear regulator 3 until the linear regulator 3 can conduct current.

[0025] Here, the linear regulator 3 will be further described. As shown in FIG. 1, the linear regulator 3 has a setting terminal 3a, an input terminal 3b, and an output terminal 3c. The setting terminal 3a is electrically connected to the control circuit 8. The input terminal 3b is electrically connected to the power line 201. The output terminal 3c is electrically connected to the irradiation module 50(60). The linear regulator 3 monitors the input voltage applied to the input terminal 3b according to the voltage applied to the setting terminal 3a, and outputs the same voltage as the input voltage applied to the input terminal 3b from the output terminal 3c. The linear regulator 3 is a so-called variable type linear regulator.

[0026] Here, if the set voltage of the linear regulator 3 is lowered, it becomes easier to protect the electronic components provided in the irradiation module 50(60). However, if the set voltage of the linear regulator 3 is lowered too much, depending on the input voltage of the linear regulator 3, the power loss in the linear regulator 3 increases. Since the capacity of the DC power supply 200 mounted on a vehicle or the like is limited, it is necessary to minimize the power loss. Also, when the power loss increases, the temperature of the output driver or the like provided in the linear regulator 3 rises due to heat generation and may exceed the maximum junction temperature. If the temperature of the output driver or the like exceeds the maximum junction temperature, there is a risk of failure.

[0027] For example, if the set voltage of the linear regulator 3 is lowered too much, when a surge voltage is applied or when the voltage from the DC power supply 200 rises (for example, when the input voltage rises from 13.5 V to 16 V), the power loss increases.

[0028] Therefore, a control circuit 8 is electrically connected to the set terminal 3a of the linear regulator 3. As shown in FIG. 1, the control circuit 8 has, for example, a resistor 5 and a Zener diode 7 (corresponding to an example of a first Zener diode). The resistor 5 and the Zener diode 7 are electrically connected to the set terminal 3a of the linear regulator 3. The resistor 5 is connected in series with the linear regulator 3. The Zener diode 7 is connected in parallel with the linear regulator 3.

[0029] If the resistor 5 and the Zener diode 7 are provided, the input voltage of the linear regulator 3 can be set by the resistor 5 and the Zener diode 7. The voltage (output voltage) applied to the irradiation module 50(60) can be clamped by the Zener diode 7. For example, when the Zener voltage of the Zener diode 7 is set to 18V, if the input voltage is less than 18V, the same voltage as the input voltage is applied to the irradiation module 50(60). When the input voltage becomes 18V or more, the voltage applied to the irradiation module 50(60) is clamped to 18V.

[0030] When setting the output voltage of the linear regulator 3, it should be a voltage lower than the lowest value among the maximum rated voltage values of the electronic components provided in the irradiation module 50(60) and higher than the upper limit value of the input voltage (for example, 16V) in a normal state.

[0031] The resistor 5 is used to limit the current. Since the Zener diode 7 is used to control the output voltage of the linear regulator 3, it can be a device that allows a smaller current to flow than the Zener diode 2, for example, a constant voltage diode.

[0032] For example, if the lowest value among the maximum rated voltage values of the electronic components provided in the irradiation module 50(60) is 20V and the upper limit value of the input voltage in a normal state is 16V, the value of the voltage input to the setting terminal 3a of the linear regulator 3 may be in the range of 16V to 20V (for example, 18V).

[0033] For example, if the lowest value among the maximum rated voltage values of the electronic components provided in the irradiation module 50(60) is 30V and the upper limit value of the input voltage in a normal state is 16V, the value of the voltage input to the setting terminal 3a of the linear regulator 3 may be in the range of 16V to 30V (for example, 28V).

[0034] In this case, it is preferable that the value of the voltage input to the setting terminal 3a of the linear regulator 3 be close to the lowest value among the maximum rated voltage values of the electronic components provided in the irradiation module 50(60). By doing so, when a surge voltage is applied and when the upper limit value of the input voltage in a normal state is applied, the power loss in the linear regulator 3 can be effectively suppressed. As a result, it is possible to effectively suppress the temperature of the output driver or the like provided in the linear regulator 3 from exceeding the maximum junction temperature.

[0035] FIG. 3 is a schematic perspective view for exemplifying the irradiation module 50. As shown in FIG. 3, the irradiation module 50 is provided with, for example, a socket 51, a substrate 52, a light emitting element 53, a circuit element 54, and a power supply terminal 55.

[0036] The socket 51 is attached to the housing of the vehicle lamp by a twist lock or the like. The socket 51 holds the substrate 52 provided with the light emitting element 53 and the circuit element 54 and the power supply terminal 55. Further, the socket 51 has a function of transmitting the heat generated in the light emitting element 53 and the circuit element 54 to the outside.

[0037] The substrate 52 is plate-shaped and is provided at one end of the socket 51. The light emitting element 53 and the circuit element 54 are electrically connected to a wiring pattern provided on the surface of the substrate 52 opposite to the socket 51 side. At least one light emitting element 53 can be provided. The light emitting element 53 can be, for example, a light emitting diode, an organic light emitting diode, a laser diode, or the like.

[0038] At least one circuit element 54 can be provided. The circuit element 54 is electrically connected to the light-emitting element 53. The circuit element 54 can be, for example, a resistor, a positive characteristic thermistor, a negative characteristic thermistor, a transistor, an integrated circuit, an arithmetic element, or the like. Note that the circuit element 54 is not limited to those exemplified, and any passive element or active element can be used as long as it is used to configure a light-emitting circuit having the light-emitting element 53.

[0039] A plurality of power supply terminals 55 are provided. The plurality of power supply terminals 55 extend inside the socket 51. One end of the plurality of power supply terminals 55 is exposed from one end of the socket 51 and is electrically connected to the wiring pattern of the substrate 52. The other end of the plurality of power supply terminals 55 is exposed from the other end of the socket 51 and is electrically connected to a control circuit that controls the lighting state of the irradiation module 50. The output terminal 3c of the vehicle surge protection device 1 is electrically connected to the power input line of the control circuit that controls the lighting state of the irradiation module 50.

[0040] FIG. 4 is a schematic cross-sectional view for exemplifying the irradiation module 60. As shown in FIG. 4, the irradiation module 60 is provided with, for example, a housing 61, a substrate 62, a discharge lamp 63, a lamp cover 64, a lighting circuit 65, a window 66, a shield 67, and a conductive member 68.

[0041] The housing 61 has a box shape and has a space inside for housing the substrate 62, the discharge lamp 63, the lamp cover 64, the lighting circuit 65, and the conductive member 68. The housing 61 is divided into a first portion 61a and a second portion 61b in the thickness direction of the housing 61. The first portion 61a can be, for example, a base to which the substrate 62, the discharge lamp 63, the lamp cover 64, the lighting circuit 65, and the conductive member 68 are attached. The second portion 61b can be, for example, a cover that covers the opening side of the first portion 61a. The second portion 61b can be detachably provided on the first portion 61a.

[0042] The substrate 62 is plate-shaped. The substrate 62 can be provided on the first portion 61a via, for example, a spacer or the like.

[0043] The discharge lamp 63 is located between the substrate 62 and the second portion 61b. The discharge lamp 63 can be detachably provided on a pair of terminal holders 63a. The pair of terminal holders 63a can be provided on the substrate 62, for example. In FIG. 4, the case where one discharge lamp 63 is provided is illustrated, but a plurality of discharge lamps 63 may be provided. At least one discharge lamp 63 may be provided.

[0044] The discharge lamp 63 can be, for example, a mercury lamp, a metal halide lamp, a dielectric barrier discharge lamp, or the like. However, the discharge lamp 63 is not limited to the illustrated ones, and any lamp capable of irradiating ultraviolet rays or light (for example, visible light) may be used.

[0045] The lamp cover 64 is located between the substrate 62 and the second portion 61b. The lamp cover 64 can be provided on the substrate 62, for example. The lamp cover 64 is box-shaped and has an opening on the surface opposite to the substrate 62 side. The discharge lamp 63 and a pair of terminal holders 63a can be provided inside the lamp cover 64.

[0046] The lighting circuit 65 is provided, for example, on the side of the substrate 62 where the discharge lamp 63 is provided. The lighting circuit 65 applies a driving voltage of a predetermined frequency to the discharge lamp 63. When a driving voltage is applied to the discharge lamp 63, for example, a discharge occurs between a pair of electrodes provided on the discharge lamp 63, and ultraviolet rays or light is radiated from the discharge lamp 63.

[0047] The lighting circuit 65 has circuit components such as, for example, a transformer 65a, a switching element 65b, and a capacitor. For example, the switching element 65b converts a DC voltage into an AC voltage of a predetermined frequency, such as a sine wave voltage. For example, the frequency of the sine wave voltage is about 100 kHz to 300 kHz. For example, the transformer 65a boosts the converted sine wave voltage to a predetermined voltage for lighting the discharge lamp 64. Note that the lighting circuit 65 may be any device that can generate a driving voltage of a predetermined frequency. The lighting circuit 65 can be, for example, various resonant inverters. The vehicle surge protection device 1 can be provided on the input side of the lighting circuit 65. Note that the vehicle surge protection device 1 can also be provided inside the housing 61 or outside the housing 61.

[0048] One end of the wiring 65c is electrically connected to the lighting circuit 65 inside the housing 61. The other end of the wiring 65c is drawn out of the housing 61 and is electrically connected to the DC power supply 200.

[0049] The window 66 is provided at a portion where a hole of the housing 61 (the second portion 61b) is provided. The window 66 has a plurality of openings that transmit ultraviolet rays and light irradiated from the discharge lamp 63. The window 66 can be, for example, formed by weaving a plurality of wire materials, or formed by forming a plurality of openings by etching or pressing.

[0050] Here, when the discharge lamp 63 is lit and discharge occurs between the electrodes of the discharge lamp 63, electromagnetic waves may be radiated together with ultraviolet rays and light. Further, when the discharge lamp 63 is lit, electromagnetic waves may be radiated from the switching element 65b provided in the lighting circuit 65 or the wiring electrically connected to the switching element 65b.

[0051] When electromagnetic waves generated in the discharge lamp 63, lighting circuit 65, etc. provided inside the housing 61 are radiated outside the housing 61, the electromagnetic waves may enter an electronic device provided near the irradiation module 60. When electromagnetic waves enter an electronic device, there is a risk that they will become electromagnetic noise and cause malfunctions of the electronic device.

[0052] Therefore, a shield 67 is provided on the outer wall of the housing 61. The shield 67 has conductivity. By using the conductive shield 67, the reflection loss in the shield 67 can be increased, so that electromagnetic waves generated inside the housing 61 can be effectively suppressed from being radiated outside the housing 61.

[0053] In this case, a shield 67a can be provided on the outer wall of the first part 61a, and a shield 67b can be provided on the outer wall of the second part 61b. And at the connection part between the first part 61a and the second part 61b, the shield 67a and the shield 67b are in contact with each other.

[0054] Here, as described above, the window 66 is provided with a plurality of openings that transmit ultraviolet rays and light irradiated from the discharge lamp 63. Therefore, there is a risk that electromagnetic waves will be radiated outside the housing 61 through the plurality of openings provided in the window 66. In this case, if a shield 67 is provided on the outer surface of the window 66, ultraviolet rays and light will not be irradiated outside the housing 61.

[0055] Therefore, the window 66 is formed of a conductive material. If the window 66 has conductivity, similar to the case of the shield 67 described above, the reflection loss in the window 66 can be increased, so that electromagnetic waves can be suppressed from being radiated outside the housing 61 through the window 66.

[0056] The conductive member 68 electrically connects the pair of terminal holders 63a and the lighting circuit 65. Therefore, by mounting the discharge lamp 63 on the pair of terminal holders 63a, the lighting circuit 65 and the discharge lamp 63 can be electrically connected.

[0057] In the above description, the case where the irradiation module 50 having the light-emitting element 53 and the circuit element 54 or the irradiation module 60 having the discharge lamp 63 and the lighting circuit 65 is electrically connected to the output terminal of the vehicle surge protection device 1 has been exemplified. However, as described above, for example, an electronic device used for vehicle operation or the like can also be electrically connected to the output terminal of the vehicle surge protection device 1. Electronic devices used for vehicle operation or the like include, for example, a display device that displays vehicle operation or the like, a drive device such as a motor. Even when an electronic device used for vehicle operation or the like is electrically connected to the output terminal of the vehicle surge protection device 1, the power loss in the linear regulator 3 can be reduced. Note that known technologies can be applied to the configuration of the electronic device used for vehicle operation or the like. Therefore, the description of the configuration of the electronic device used for vehicle operation or the like is omitted.

[0058] As described above, some embodiments of the present invention have been exemplified, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, changes, etc. can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope. Also, the above-described embodiments can be implemented in combination with each other.

Explanation of Reference Numerals

[0059] 1 Vehicle surge protection device, 2 Zener diode, 3 Linear regulator, 4 Capacitor, 5 Resistor, 7 Zener diode, 8 Control circuit, 50 Irradiation module, 51 Socket, 52 Substrate, 53 Light-emitting element, 54 Circuit element, 60 Irradiation module, 62 Substrate, 63 Discharge lamp, 65 Lighting circuit, 100 Vehicle irradiation device, 200 DC power supply

Claims

1. A vehicle surge protection device electrically connected to an electronic component provided in a vehicle, comprising: a first surge protection circuit; a control circuit provided on the input side of the first surge protection circuit for controlling the value of the input voltage of the first surge protection circuit; and the control circuit is configured such that the value of the input voltage of the first surge protection circuit is lower than the maximum rated voltage value of the electronic component and higher than the upper limit value of the input voltage in a normal state.

2. The vehicle surge protection device according to claim 1, wherein the control circuit includes a resistor and a first Zener diode.

3. The vehicle surge protection device according to claim 1 or 2, wherein the first surge protection circuit includes a linear regulator.

4. The vehicle surge protection device according to any one of claims 1 to 3, further comprising a second surge protection circuit provided on the input side of the control circuit.

5. An irradiation module; the vehicle surge protection device according to any one of claims 1 to 4, electrically connected to the irradiation module; and a vehicle irradiation device comprising the same.

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