JP7172143B2 - vehicle lamp - Google Patents

Description

The present invention relates to a vehicle lamp.

Conventionally, in a single lighting mode, self-heating of the drive circuit is detected based on the detection result of one temperature detection element on the drive circuit side, and control is performed to suppress the output of the light source. As a result, the drive circuit achieves both protection from self-heating and protection from the light source side, which is the load side. However, in the case of such control, even if a plurality of lighting modes are implemented, the drive circuit will set the temperature of the light source side based on the same threshold temperature according to the detection result of one temperature detection element on the drive circuit side. Since the output is controlled to be suppressed, the output of the light source is controlled to be suppressed even in an environment where the vehicular lamp can actually be used.

Therefore, even if there is only one temperature detection element, by providing a plurality of power conversion circuits, it has been proposed to maintain the performance without dimming even under the environment in which the vehicle lamp can be used. (See Patent Document 1, for example).

JP 2009-154748 A

However, the conventional technology as described in Patent Document 1 requires a power conversion circuit for each lighting mode, which increases the number of parts. Therefore, in the prior art as described in Patent Document 1, even if a plurality of lighting modes are implemented, it is not possible to reduce component costs while maintaining performance.

The present disclosure has been made in view of such circumstances, and is intended to reduce component costs while maintaining performance even when a plurality of lighting modes are implemented.

A vehicle lamp, which is one aspect of the present disclosure, includes a first light source unit, a second light source unit connected in series with the first light source unit, and the first light source unit and the second light source unit. a driving circuit for driving the light source unit according to a plurality of lighting modes , the driving circuit comprising: a power conversion circuit for supplying output power to the first light source unit and the second light source unit; A temperature detection element mounted on a circuit for detecting an ambient temperature, and a lighting control circuit for starting suppression control for suppressing power consumption of the power conversion circuit based on the ambient temperature detected by the temperature detection element. The lighting control circuit starts the suppression control when a value obtained by adding the ambient temperature and a positive offset value corresponding to the current lighting mode among the plurality of lighting modes reaches a set target value. The set target value is set differently according to each of the plurality of lighting modes, and each set target value of the plurality of lighting modes has a large power consumption when the ambient temperature is the same among the plurality of lighting modes. The higher the temperature, the higher it is set .

Further, in the vehicle lamp according to one aspect of the present disclosure, the suppression control follows a control function for suppressing the power consumption according to the ambient temperature, and the control function is based on the ambient temperature and the power consumption. It is preferable that there is a linear function relationship with power, and that the ambient temperature decreases as the power consumption increases.

According to one aspect of the present disclosure, it is possible to reduce component costs while maintaining performance even when a plurality of lighting modes are implemented.

1 is a diagram showing a structural example of a vehicle lamp according to an embodiment to which the present disclosure is applied; FIG. It is a top view of a light source assembly 5 according to an embodiment to which the present disclosure is applied. It is a figure showing the control target characteristic of light source part 5c and light source part 5d concerning an embodiment to which this indication is applied. 2 is a block diagram showing an example of a functional configuration of a drive circuit 4 that realizes a plurality of lighting modes according to an embodiment to which the present disclosure is applied; FIG. FIG. 4 is a diagram showing a control table 4b1 in which correspondence relationships between inputs, outputs, set target values, and offset values of the drive circuit 4 corresponding to each lighting mode are specified according to the embodiment to which the present disclosure is applied; 4 is a diagram showing the relationship between ambient temperature and power consumption of the drive circuit 4 according to the embodiment to which the present disclosure is applied; FIG. Fig. 10 is a diagram showing control target characteristics of the light source unit 5c and the light source unit 5d for each lighting mode according to the embodiment to which the present disclosure is applied; 2 is a block diagram showing an example of the functional configuration of a drive circuit 40 that implements a conventional single lighting mode; FIG. It is a figure which shows the control target characteristic of the light source part 5c which takes charge of the conventional single lighting mode. FIG. 4 is a block diagram showing an example of the functional configuration of a drive circuit 400 that implements a plurality of conventional lighting modes; FIG. 5 is a diagram showing control target characteristics of a conventional light source unit 5c and a light source unit 5d that are in charge of a plurality of lighting modes; FIG. 10 is a diagram showing the relationship between the ambient temperature and the power consumption of the drive circuit 400, which are responsible for a plurality of conventional lighting modes. FIG. 10 is a block diagram showing another example of the functional configuration of a drive circuit 4000 that implements a plurality of conventional lighting modes;

Hereinafter, embodiments of a vehicle lamp to which the present disclosure is applied will be described in detail based on the drawings. Note that the present disclosure is not limited by this embodiment.

(Outline configuration)
FIG. 1 is a diagram showing a structural example of a vehicle lamp according to an embodiment to which the present disclosure is applied. A vehicle lamp is, for example, a headlamp, and headlamp units are mounted on both left and right ends of a front portion of a vehicle. The vehicle lamp includes a lamp housing 1 , a lamp lens 2 , a drive circuit 4 , a light source assembly 5 , an optical section 6 and a radiator 7 . A lamp lens 2 is fitted along the edge of the lamp housing 1, and a gap between the lamp housing 1 and the lamp lens 2 is filled with a water intrusion prevention seal 3. - 特許庁A drive circuit 4 , a light source assembly 5 , an optical section 6 and a radiator 7 are provided inside the lamp housing 1 . The drive circuit 4, which will be described later in detail with reference to FIG. A radiator 7 is provided above the drive circuit 4 . A light source assembly 5 is provided on the upper surface side of the radiator 7 , and heat is radiated from the light source assembly 5 by the radiator 7 . An optical section 6 is attached so as to cover the upper portion of the light source assembly 5 , and light emitted from the light source assembly 5 is transmitted to the optical section 6 .

FIG. 2 is a top view of a light source assembly 5 according to an embodiment to which the present disclosure is applied. The light source assembly 5 is provided with a light source portion 5c and a light source portion 5d on a substrate 5b, and is attached to the heat radiator 7 with metal fittings (not shown). The light source section 5c and the light source section 5d each consist of a plurality of light emitting elements 51, and the plurality of light emitting elements 51 are connected in series. Each of the plurality of light emitting elements 51 is composed of, for example, an LED (Light Emitting Diode). Although illustration is omitted, the light output from the light source units 5c and 5d is reflected inside the optical unit 6 and output along the optical axis of the optical unit 6. FIG. Also, one of the light source section 5c and the light source section 5d corresponds to the first light source section in the present invention, and the other corresponds to the second light source section in the present invention.

FIG. 3 is a diagram showing control target characteristics of the light source unit 5c and the light source unit 5d according to the embodiment to which the present disclosure is applied. In mode (A), for example, the lighting mode is a low beam mode. In mode (B), for example, the lighting mode is the high beam mode. In any lighting mode, suppression of the driving power of the light source unit 5c and the light source unit 5d is started from the control start temperature Ta1. That is, the control start temperature Ta1 is set to the temperature at which suppression of the driving power of the light source units 5c and 5d is started. There is a correlation between the driving power of the light source section 5c and the light source section 5d and the power consumption of the driving circuit 4. FIG. Therefore, it is possible to suppress the driving power of the light source section 5c and the light source section 5d by suppressing the power consumption of the driving circuit 4. FIG.

(circuit configuration)
FIG. 4 is a block diagram showing an example of the functional configuration of the drive circuit 4 that realizes a plurality of lighting modes according to the embodiment to which the present disclosure is applied. The drive circuit 4 includes a power conversion circuit 4a, a lighting control circuit 4b, a temperature detection element 4c, and an output switching element 4d, and drives the light source section 5c and the light source section 5d. The power conversion circuit 4a supplies output power to the light source section 5c and the light source section 5d. The power conversion circuit 4a is a DC-DC converter, and is composed of, for example, a switching regulator. The output switching element 4d is provided in parallel with the light source section 5d. When the output switching element 4d is in the ON state, the input current input from the driving circuit 4 bypasses the light source section 5d and flows to the light source section 5c. It is a bypass circuit for passing an input current to the light source section 5d. The output switching element 4d is composed of, for example, a semiconductor switching element such as a MOSFET or a transistor, and is controlled to either an ON state or an OFF state according to an output switching signal from the lighting control circuit 4b. The semiconductor switching element may be a power semiconductor made of SiC (Silicon Carbide).

The temperature detection element 4c is mounted on the drive circuit 4 to detect the ambient temperature of the drive circuit 4, and is composed of, for example, a thermistor. The lighting control circuit 4b refers to the control table 4b1 based on the ambient temperature detected by the temperature detection element 4c, and starts suppression control to suppress the power consumption of the power conversion circuit 4a. The suppression control follows a control function that suppresses the power consumption of the power conversion circuit 4a according to the ambient temperature, and is started when the ambient temperature reaches a set target value. The set target value is set to a different value corresponding to each of a plurality of lighting modes. The lighting control circuit 4b starts suppression control when the value obtained by adding the positive offset value to the ambient temperature reaches the set target value. The set target value will be described later with reference to FIGS. 5 to 7. FIG. The control function has a linear function relationship between the ambient temperature detected by the temperature detection element 4c and the power consumption of the power conversion circuit 4a. relationship. That is, the higher the ambient temperature, the more the power consumption of the power conversion circuit 4a is controlled. If the lighting mode is the low beam mode, the output switching element 4d is turned on according to the input (A), and the light source section 5c, which is the output (A), is turned on. Further, if the lighting mode is the high beam mode, the output switching element 4d is turned off according to the input (A) and the input (B), and the light source unit 5c is the output (A) and the output (B). The light source unit 5d is turned on.

FIG. 5 is a diagram showing a control table 4b1 in which the correspondence relationship between the input and output of the drive circuit 4, the set target value, and the offset value corresponding to each lighting mode according to the embodiment to which the present disclosure is applied is specified. . If input (A) is on or lighting input signal (A) is on and input (B) is off or lighting input signal (B) is off, only output (A) is on or light source Only the portion 5c is controlled to the lighting state when the lighting mode is mode (A). When the lighting mode is mode (A), it corresponds to the low beam mode, the set target value is set to, for example, 100° C., and the offset value of α1 is set. On the other hand, when the input (A) is on, that is, the lighting input signal (A) is on, and the input (B) is on, that is, the lighting input signal (B) is on, the output (A) and the output (B) ) are turned on, that is, both the light source section 5c and the light source section 5d are controlled to be in the lighting state in the mode (B). When the lighting mode is mode (B), it corresponds to the high beam mode, the set target value is set to, for example, 120° C., and the offset value of α2 is set.

FIG. 6 is a diagram showing the relationship between ambient temperature and power consumption of the drive circuit 4 according to the embodiment to which the present disclosure is applied. As shown in FIG. 6, if the lighting mode is the low beam mode, the set target value is 100.degree. On the other hand, if the lighting mode is the high beam mode, the set target value is 120°C. By changing the set target value according to the lighting mode in this manner, the heat dissipation performance of the drive circuit 4 becomes the same for the ambient temperature and the power consumption of the drive circuit 4 . Among the plurality of lighting modes, the set target value is set to a higher temperature as the power consumption increases when the ambient temperature is the same. Specifically, the set target value is set to a higher temperature for the high beam mode than for the low beam mode among the plurality of lighting modes . That is, when the lighting mode is the low beam mode, the control start temperature Ta1 plus the offset value of α1 becomes the set target value for the low beam mode , and when the lighting mode is the high beam mode, the control start temperature Ta1 plus an offset value of α2 (>α1) is the set target value for the high beam mode . In order to suppress the power consumption of the driving circuit 4, the driving power of the light source section 5c and the light source section 5d is suppressed. In order to suppress the driving power of the light source section 5c and the light source section 5d, the power consumption of the power conversion circuit 4a is suppressed. Also, the power conversion circuit 4a is a portion that consumes the most power in the circuit configuration of the drive circuit 4. FIG. Therefore, in order to suppress the power consumption of the drive circuit 4, the power consumption of the power conversion circuit 4a is suppressed.

(circuit operation)
FIG. 7 is a diagram showing control target characteristics of the light source unit 5c and the light source unit 5d for each lighting mode according to the embodiment to which the present disclosure is applied. When the lighting mode is the low beam mode, the set target value of 100° C. and the offset value of α1 are read from the control table 4b1. The light source unit 5c is driven by the drive circuit 4, and the ambient temperature starts to rise as the power conversion circuit 4a is driven. When the ambient temperature detected by the temperature detection element 4c reaches the control start temperature Ta1, the set target value is obtained by adding the offset value of α1 to the control start temperature Ta1. start reducing power consumption. On the other hand, when the lighting mode is the high beam mode, the set target value of 120° C. and the offset value of α2 are read from the control table 4b1. By driving the drive circuit 4, the light source unit 5d is driven in addition to the light source unit 5c, and the ambient temperature starts to rise as the power conversion circuit 4a is driven. When the ambient temperature detected by the temperature detection element 4c reaches the control start temperature Ta1, the set target value is obtained by adding the offset value α2 to the control start temperature Ta1. Suppression of the power consumption of 4a is started .

(Effect)
Next, the effect of this embodiment is demonstrated, comparing with a conventional example. FIG. 8 is a block diagram showing an example of the functional configuration of a drive circuit 40 that implements a conventional single lighting mode. FIG. 9 is a diagram showing the control target characteristics of the conventional light source unit 5c responsible for a single lighting mode. As shown in FIGS. 8 and 9, conventionally, the power consumption of the power conversion circuit 40a is suppressed by the lighting control circuit 40b based on the detection result of one temperature detection element 40c. On this premise, conventional examples will be examined for a plurality of lighting modes. FIG. 10 is a block diagram showing an example of the functional configuration of a drive circuit 400 that realizes a plurality of conventional lighting modes. FIG. 11 is a diagram showing the control target characteristics of the conventional light source units 5c and 5d that are responsible for a plurality of lighting modes. FIG. 12 is a diagram showing the relationship between the ambient temperature and the power consumption of the drive circuit 400, which are responsible for a plurality of conventional lighting modes.

Regardless of the lighting mode, the set target value of the temperature detection element 400c set in the control table 400b1 is the same. However, when the lighting mode is mode (A), the light source unit 5c is lit by the output switching element 400d. Since the portion 5d is lit, the drive power for driving the light source portions 5c and 5d, ie, the output power of the drive circuit 400, differs between mode (A) and mode (B). Therefore, since the power consumption of the driving circuit 400 differs between the mode (A) and the mode (B), the self-heating of the power conversion circuit 400a also depends on the driving power for driving the light source section 5c and the light source section 5d. changes relative to Since the control start temperature Ta1 and the control start temperature Ta2 are different due to the difference in the driving power of the light source unit 5c and the light source unit 5d for each lighting mode, the temperature is detected when the control start temperature Ta1 is reached in the case of mode (A). The ambient temperature detected by the element 400c is different from the ambient temperature detected by the temperature detection element 400c when the control start temperature Ta2 is reached in mode (B). As a result, the difference between the suppression rate of the driving power of the light source units 5c and 5d in the mode (A) and the suppression rate of the driving power of the light source units 5c and 5d in the mode (B) is , the difference between the control start temperature Ta1 in the mode (A) and the control start temperature Ta2 in the mode (B). Specifically, as a result of adding the drive power for the light source unit 5c to the light source unit 5d for the driving power only for the light source unit 5c, the control start temperature Ta2 for the power consumption suppression control of the drive circuit 400 is higher than the control start temperature Ta1. Change to low temperature side. As a result, the suppression control of the power consumption of the power conversion circuit 400a by the lighting control circuit 400b is out of the protection range of the drive circuit 400 or the self-heating of the light source unit 5c and the light source unit 5d. Even under environmental conditions, it leads to performance degradation.

FIG. 13 is a block diagram showing another example of the functional configuration of a drive circuit 4000 that implements a plurality of conventional lighting modes. As shown in FIG. 13, a power conversion circuit 4000a1 is provided as a circuit configuration for which the lighting mode corresponds to mode (A), and a power conversion circuit 4000a2 is provided as a circuit configuration for which the lighting mode corresponds to mode (B). , the control table 4000b1 is referred to based on the detection result of the temperature detection element 4000c, and the output power of the power conversion circuit 4000a1 or the power conversion circuit 4000a2 is suppressed by the lighting control circuit 4000b. Since the power conversion circuit 4000a1 and the power conversion circuit 4000a2 are provided in this way, the number of parts is increased.

Therefore, in the present embodiment, when the value obtained by adding the offset value to the ambient temperature detected by the temperature detecting element 4c reaches the set target value, suppression control is started. The suppression control follows a control function that suppresses the power consumption of the power conversion circuit 4a according to the ambient temperature, and is started when the ambient temperature detected by the temperature detection element 4c reaches a set target value. is. The set target value is set to a different value depending on each of a plurality of lighting modes. Therefore, the suppression control eliminates the need to provide the power conversion circuit 4a for each of the plurality of lighting modes, so the number of parts can be suppressed. Moreover, since a positive offset value is added to the ambient temperature detected by the temperature detection element 4c, suppression control is not started from a low temperature. Therefore, even if a plurality of lighting modes are implemented, it is possible to reduce component costs while maintaining performance.

In this embodiment, the set target value is set to a higher temperature as the power consumption of the power conversion circuit 4a increases when the ambient temperature detected by the temperature detecting element 4c is the same. Therefore, it is possible to prevent the suppression control from being started when the ambient temperature detected by the temperature detecting element 4c is low, so that it is possible to avoid a state in which the performance as a light source deteriorates.

In this embodiment, the control function has a linear function relationship between the ambient temperature detected by the temperature detection element 4c and the power consumption of the power conversion circuit 4a, and the power consumption of the power conversion circuit 4a is As the temperature increases, the ambient temperature detected by the temperature detection element 4c decreases. Therefore, even in a vehicle lamp having a plurality of lighting modes, the single power conversion circuit 4a is suppressed and controlled by simple control. Low power consumption of the circuit 4 can be achieved.

As described above, the vehicle lamp to which the present disclosure is applied has been described based on the embodiment, but the present disclosure is not limited to this, and modifications may be made without departing from the gist of the present disclosure.

For example, an example in which the lighting modes are the low beam mode and the high beam mode has been described, but the present invention is not particularly limited to this. For example, the lighting mode may be a daytime running mode, a turn lamp mode, and a clearance lamp mode.

Also, for example, an example in which the output switching element 4d is configured by a semiconductor switching element has been described, but the present invention is not particularly limited to this. For example, the output switching element 4d may be composed of an electromagnetic relay.

1 lamp housing, 2 lamp lens, 3 water intrusion prevention seal 4, 40, 400, 4000 drive circuit 4a, 40a, 400a power conversion circuit 4000a1, 4000a2 power conversion circuit 4b, 40b, 400b, 4000b lighting control circuit 4b1, 400b1, 4000b1 Control table 4c, 40c, 400c, 4000c Temperature detection element 4d, 400d Output switching element 5 Light source assembly 5b Substrate 5c Light source unit 5d Light source unit 51 Light emitting element 6 Optical unit 7 Radiator Ta1, Ta2 Control start temperature

Claims (2)

a first light source;
a second light source unit connected in series with the first light source unit;
a drive circuit that drives the first light source unit and the second light source unit according to a plurality of lighting modes ;
with
The drive circuit is
a power conversion circuit that supplies output power to the first light source unit and the second light source unit;
a temperature detection element that is mounted on the drive circuit and detects ambient temperature;
a lighting control circuit that starts suppression control to suppress power consumption of the power conversion circuit based on the ambient temperature detected by the temperature detection element;
with
The lighting control circuit is
When a value obtained by adding the ambient temperature and a positive offset value corresponding to the current lighting mode among the plurality of lighting modes reaches a set target value, starting the suppression control ,
The set target value is set differently according to each of a plurality of lighting modes,
The set target values of the plurality of lighting modes are set to higher temperatures as the power consumption of the plurality of lighting modes increases when the ambient temperature is the same.
Vehicle lighting. The suppression control is
It follows a control function that suppresses the power consumption according to the ambient temperature,
The control function is
The relationship between the ambient temperature and the power consumption is a linear function, and the relationship is such that the ambient temperature decreases as the power consumption increases.
The vehicle lamp according to claim 1 .

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