Vehicle lamp

Abstract

The light-emitting unit (110) includes a first semiconductor light-emitting element (112) for low beam and a second semiconductor light-emitting element (114) for high beam. The first driving module (120) lights the first semiconductor light emitting element (112). The second driving module (140) lights the second semiconductor light-emitting element (114). The first converter controller (124) feedback controls the first DC / DC converter (122) such that a first drive current (IDRVL) generated by the first DC / DC converter (122) approaches a first target amount (IREFL1). The second driving module (140) responds to the lighting indication of the high beam and sends a dimming indication signal (DIM) to the first driving module (120). The first driving module (120) causes the first driving current (IDRVL) to be lower than a second target amount (IREFL2) that is smaller than the first target amount (IREFL1) in response to the dimming indication signal (DIM).

Description

Technical Field

[0001] The present disclosure relates to a vehicle lamp used in automobiles and the like. Background Art

[0002] In recent years, semiconductor light sources, such as LEDs (light-emitting diodes) and LDs (laser diodes), have been increasingly adopted as light sources for vehicle lighting fixtures such as high-beam and low-beam headlights and rear combination lamps. Semiconductor light sources offer advantages over conventional light sources such as HID (High Intensity Discharge) lamps and halogen lamps in terms of energy efficiency, ease of maintenance, and design versatility.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2010-241347

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2011-098611 Summary of the Invention

[0007] Technical problem to be solved by the invention

[0008] Vehicle lamps for commercial vehicles such as trucks are required to be low-cost. To meet this demand, a lineup of vehicle lamps has been developed that integrates high-beam and low-beam light-emitting elements into a single unit. During high-beam mode, both the high-beam and low-beam light sources are illuminated simultaneously to meet lighting conditions, generating increased heat. Therefore, heat dissipation solutions are crucial for integrated high-beam and low-beam vehicle lamps. Especially in commercial vehicle lamps, where long-term reliability is required and fanless operation is sometimes required, heat dissipation solutions are even more challenging.

[0009] The present disclosure is obtained in the relevant circumstances, and one exemplary purpose of one embodiment thereof is to provide a vehicle lamp that satisfies light distribution conditions and implements a heat dissipation solution.

[0010] Methods used to solve technical problems

[0011] One embodiment of the present disclosure relates to a vehicle lamp. The vehicle lamp includes: a light-emitting unit including a first semiconductor light-emitting element for low beam and a second semiconductor light-emitting element for high beam; a first driver module that lights up the first semiconductor light-emitting element; and a second driver module that lights up the second semiconductor light-emitting element. The first driver module includes: a first DC / DC converter that supplies a first drive current to the first semiconductor light-emitting element; and a first converter controller that feedback-controls the first DC / DC converter in such a way that the first drive current generated by the first DC / DC converter approaches a first target amount. The second driver module sends a dimming indication signal to the first driver module in response to a high beam lighting indication. The first driver module causes the first drive current to be lower than a second target amount that is smaller than the first target amount in response to the dimming indication signal.

[0012] A vehicle lamp according to one embodiment of the present disclosure includes: a first semiconductor light-emitting element for low beam; a second semiconductor light-emitting element for low beam; a first lighting circuit that illuminates the first semiconductor light-emitting element and activates a first fault signal upon detecting an abnormality; a second lighting circuit that illuminates the second semiconductor light-emitting element and activates a second fault signal upon detecting an abnormality; and a latch circuit that activates a stop signal upon activation of at least one of the first fault signal or the second fault signal. The first lighting circuit and the second lighting circuit extinguish the first and second semiconductor light-emitting elements in response to activation of the stop signal.

[0013] It should be noted that any combination of the aforementioned components, or any substitution of components or expressions in methods, devices, systems, etc., are also valid as embodiments of the present invention or disclosure. Furthermore, the description of this item (method for solving a technical problem) does not describe all the features that are indispensable to the present invention; therefore, a subset of these features may also constitute the present invention.

[0014] Effects of the Invention

[0015] According to an embodiment of the present disclosure, light distribution conditions are met and a heat dissipation solution can be implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a block diagram of the vehicle lamp according to the first embodiment.

[0017] Figure 2 It is an explanation Figure 1 Waveform diagram of the operation of vehicle lamps.

[0018] Figure 3 (a) is a diagram illustrating the light distribution when the low beam is on. Figure 3 (b) is a diagram illustrating light distribution when the high beam is on.

[0019] Figure 4 It shows Figure 1 A block diagram of an embodiment of a vehicle lamp.

[0020] Figure 5 : is a circuit diagram showing a configuration example of a derating circuit.

[0021] Figure 6 This is a block diagram of the second driving module in the second embodiment.

[0022] Figure 7 This is a block diagram of the second driving module in Embodiment 3.

[0023] Figure 8 This is a block diagram of a vehicle lamp according to a fourth embodiment.

[0024] Figure 9 It shows Figure 8 A diagram showing an example of low beam distribution of a vehicle lamp. DETAILED DESCRIPTION

[0025] (Overview of Embodiments)

[0026] The present disclosure provides an overview of several exemplary embodiments. This overview serves as a preface to the detailed description that follows, and is intended to provide a basic understanding of the embodiments. It briefly describes several concepts of one or more embodiments and is not intended to limit the scope of the invention or disclosure. This overview is not a comprehensive overview of all embodiments that should be considered, nor is it intended to limit the important elements of all embodiments, nor is it intended to define the scope of some or all of the schemes. For convenience, "one embodiment" is sometimes used to indicate one embodiment (an embodiment or a variation) or multiple embodiments (an embodiment or a variation) disclosed in this specification.

[0027] A vehicle lamp according to one embodiment includes: a light-emitting unit comprising a first semiconductor light-emitting element for low beam and a second semiconductor light-emitting element for high beam; a first driver module for illuminating the first semiconductor light-emitting element; and a second driver module for illuminating the second semiconductor light-emitting element. The first driver module includes: a first DC / DC converter for supplying a first drive current to the first semiconductor light-emitting element; and a first converter controller for feedback-controlling the first DC / DC converter so that the first drive current generated by the first DC / DC converter approaches a first target value. The second driver module transmits a dimming instruction signal to the first driver module in response to a high beam lighting instruction. In response to the dimming instruction signal, the first driver module reduces the first drive current to a second target value that is smaller than the first target value.

[0028] With this configuration, the second driver module transmits a dimming instruction to the first driver module, allowing the first driver module to detect that the high-beam lighting period has arrived. Furthermore, the first driver module reduces the first drive current in response to the dimming instruction, thereby reducing the amount of light emitted by the first semiconductor light-emitting element. This can suppress an increase in the total heat generated by the light-emitting unit during high-beam lighting.

[0029] In one embodiment, the first converter controller may include an analog dimming terminal, and the first target value may be based on a dimming voltage generated at the analog dimming terminal. The first driver module may further include a dimming circuit that reduces the dimming voltage in response to a dimming instruction signal. By utilizing the dimming pins available on most commercially available driver ICs (Integrated Circuits), the first drive current can be reduced without adding new pins.

[0030] In one embodiment, the second driving module may include a first linear regulator that is enabled in response to a high beam lighting instruction, and an output voltage of the first linear regulator is supplied to the first driving module as a dimming instruction signal.

[0031] In one embodiment, the device may further include: an interface circuit for receiving a high beam lighting instruction; and a microcontroller for enabling the first linear regulator in response to the lighting instruction received by the interface circuit.

[0032] In one embodiment, the high beam lighting indication may be provided as a supply of power supply voltage to the second driving module, and the vehicle lamp may further include: a second linear regulator that operates when supplied with the power supply voltage; and a microcontroller that is started when supplied with the output voltage of the second linear regulator to enable the first linear regulator.

[0033] In one embodiment, the vehicle lamp may be fanless. In commercial vehicles that require long-term reliability, fanless operation is sometimes required. The above structure can meet this requirement.

[0034] A vehicle lamp according to one embodiment includes: a first semiconductor light-emitting element for low beam; a second semiconductor light-emitting element for low beam; a first lighting circuit that illuminates the first semiconductor light-emitting element and activates a first fault signal upon detecting an abnormality; a second lighting circuit that illuminates the second semiconductor light-emitting element and activates a second fault signal upon detecting an abnormality; and a latch circuit that activates a stop signal upon activation of at least one of the first fault signal and the second fault signal. The first lighting circuit and the second lighting circuit extinguish the first and second semiconductor light-emitting elements in response to activation of the stop signal.

[0035] According to this structure, when a failure is detected in any one of the multiple LEDs (semiconductor light emitting elements), all the LEDs are turned off. Therefore, the visual indicator is removed from the mandatory configuration requirements and the indicator is no longer required.

[0036] In one embodiment, the first lighting circuit may determine that the voltage between both ends of the first semiconductor light emitting element is abnormal when it deviates from a normal range, and the second lighting circuit may determine that the voltage between both ends of the second semiconductor light emitting element is abnormal when it deviates from a normal range.

[0037] In one embodiment, the first lighting circuit and the second lighting circuit may each include a DC / DC converter and a controller circuit for feedback-controlling the DC / DC converter so that an output current of the DC / DC converter approaches a target current.

[0038] (Implementation Method)

[0039] The following describes preferred embodiments with reference to the accompanying drawings. Identical or equivalent components, parts, and processes shown in the various drawings are denoted by the same reference numerals, and duplicate descriptions are omitted as appropriate. The embodiments are not intended to limit the disclosure and invention but rather to illustrate them. Not all features or combinations thereof described in the embodiments constitute essential parts of the disclosure and invention.

[0040] In this specification, the so-called "state in which component A is connected to component B" includes the situation in which component A and component B are physically directly connected, and also includes the situation in which component A and component B are indirectly connected via other components that have no substantial impact on their electrical connection state or do not damage the function or effect achieved through their coupling.

[0041] Similarly, the so-called "state in which component C is arranged between component A and component B" means, in addition to the case of directly connecting component A and component C, or directly connecting component B and component C, it also includes the case of indirect connection via other components without substantially affecting their electrical connection state or damaging the function or effect achieved by their coupling.

[0042] In addition, in this specification, electrical signals such as voltage signals and current signals, or reference numerals marked on circuit elements such as resistors, capacitors, and inductors also represent their respective voltage values, current values, or circuit constants (resistance value, capacitance value, inductance) as needed.

[0043] (Implementation Method 1)

[0044] Figure 1 1 is a block diagram of a vehicle lamp 100 according to Embodiment 1. The vehicle lamp 100 includes a light emitting unit 110 , a first driving module 120 , and a second driving module 140 .

[0045] The light-emitting unit 110 includes a first semiconductor light-emitting element 112 for low beam and a second semiconductor light-emitting element 114 for high beam, which are integrated. For example, the first semiconductor light-emitting element 112 and the second semiconductor light-emitting element 114 are mounted on a common printed circuit board. In addition, the emitted light of the first semiconductor light-emitting element 112 and the second semiconductor light-emitting element 114 can also pass through a common optical system. The first semiconductor light-emitting element 112 and the second semiconductor light-emitting element 114 can respectively include one or more LEDs (light-emitting diodes). For example, on the printed circuit board, the multiple LEDs constituting the first semiconductor light-emitting element 112 are arranged in a row in the horizontal direction, and adjacent to them, the multiple LEDs constituting the second semiconductor light-emitting element 114 are arranged in a row in the horizontal direction. A common heat sink can be installed in the first semiconductor light-emitting element 112 and the second semiconductor light-emitting element 114.

[0046] The first driving module 120 lights up the first semiconductor light emitting element 112 in response to the low beam lighting instruction. BAT As the input voltage V L , is supplied to the first driving module 120 via the low beam switch SW1. In this embodiment, the low beam switch SW1 is turned on, and the power supply voltage V BAT (V L ) is supplied to the first driving module 120 to indicate the lighting of the low beam.

[0047] The first driving module 120 includes a first DC / DC converter 122 , a first converter controller 124 , and a first interface circuit 126 .

[0048] The first DC / DC converter 122 is controlled by a pulse modulation signal S supplied from a first converter controller 124. P1 The first semiconductor light emitting element 112 is switched to supply the first driving current I DRVL For example, the pulse modulation signal S P1 It can be a pulse width modulation signal or a pulse frequency modulation signal.

[0049] The first converter controller 124 generates a first driving current I DRVL Approaching the first target amount I REFL1 Generate pulse modulation signal S in the form of P1 , feedback control (constant current control) is performed on the first DC / DC converter 122. Specifically, the first converter controller 124 receives the first drive current I DRVL Corresponding feedback signal (current detection signal) V FB1 , with the feedback signal VFB Close to the first reference voltage V REF1 The feedback control pulse modulation signal S P1 duty cycle.

[0050] The first interface circuit 126 receives the dimming indication signal DIM from the second driving module 140. In response to the dimming indication signal DIM being asserted (eg, high), the first interface circuit 126 drives the first driving current I DRVL Reduced to less than the first target amount I REFL1 A smaller second target amount I REFL2 In this way, it acts on the first converter controller 124.

[0051] The second driving module 140 lights up the second semiconductor light emitting element 114 in response to the high beam lighting instruction. BAT As the input voltage V H is supplied to the second driving module 140 .

[0052] In this embodiment, the second driving module 140 includes a second lighting circuit 150 and a second interface circuit 146 .

[0053] The second lighting circuit 150 controls the second driving current I flowing through the second semiconductor light emitting element 114 so as to form a high beam light distribution. DRVH In this embodiment, the second lighting circuit 150 has the same configuration as the first driving module 120 , and includes a second DC / DC converter 152 and a second converter controller 154 .

[0054] The second DC / DC converter 152 is controlled by a pulse modulation signal S supplied from a second converter controller 154. P2 The second semiconductor light emitting element 114 is switched to supply the second driving current I DRVH For example, the pulse modulation signal S P2 It can be a pulse width modulation signal or a pulse frequency modulation signal.

[0055] For example, the second converter controller 154 may use the second drive current I generated by the second DC / DC converter 152 DRVH Approaching the second target amount I REFH In the feedback control (constant current control) mode, the pulse modulation signal S P2 .

[0056] Alternatively, the second lighting circuit 150 may include a constant current source (not shown) connected in series with the second semiconductor light emitting element 114. In this case, the second converter controller 154 may also supply a driving voltage V to the series connection circuit of the second semiconductor light emitting element 114 and the constant current source. DRV2The second converter controller 154 can also drive the voltage V DRV2 Close to the target voltage V REF2 The feedback control pulse modulation signal S P2 .

[0057] In addition, the second driving module 140 sends a dimming indication signal DIM to the first driving module 120 in response to the high beam lighting indication.

[0058] In this embodiment, the high beam switch SW2 is turned on, and the power supply voltage V BAT (V H ) is supplied to the second driving module 140 to become the high beam lighting instruction. The second interface circuit 146 receives the input voltage V H When supplied, the dimming instruction signal DIM is enabled.

[0059] The above is the structure of the vehicle lamp 100. Next, its operation will be described.

[0060] Figure 2 It is an explanation Figure 1 The waveform diagram of the operation of the vehicle lamp 100. Before time t0, the vehicle lamp 100 is in the off state. At time t0, the low beam switch SW1 is turned on, generating a low beam light on instruction. In response to the low beam light on instruction, the first driver module 120 supplies the first semiconductor light emitting element 112 with a power supply stabilized at the first target amount I REFL1 The first driving current I DRVL As a result, the first semiconductor light emitting element 112 emits light at a relatively bright first brightness, forming a low-beam light distribution.

[0061] At time t1, the high beam switch SW2 is turned on, generating a high beam light indication. In response to the high beam light indication, the second driving module 140 supplies a second driving current I to the second semiconductor light emitting element 114. DRVH As a result, the second semiconductor light emitting element 114 emits light, forming a high-beam light distribution.

[0062] At time t1, when the high beam on instruction is generated, the dimming instruction signal DIM is set to be valid. In response to the dimming instruction signal DIM, the first driving module 120 supplies the first driving current I to the first semiconductor light emitting element 112. DRVL Reduce to the second target amount I REFL2 As a result, the first semiconductor light emitting element 112 emits light at a second brightness that is relatively lower than the state in which only the low beam is turned on.

[0063] At time t2, when the high beam switch SW2 is turned off, the second driving current I DRVH=0A, and the second semiconductor light emitting element 114 is turned off. In the second driving module 140, the dimming indication signal DIM is invalid. After the dimming indication signal DIM is invalid, the first driving module 120 makes the first driving current I DRVL The target current returns to the first target quantity I REFL1 As a result, the first semiconductor light emitting element 112 emits light at a relatively bright first brightness.

[0064] Figure 3 (a) is a diagram illustrating the light distribution when the low beam is on. Figure 3 (b) is a diagram illustrating the light distribution when the high beam is on. Figure 3 As shown in (a), when the low beam is on, the first semiconductor light emitting element 112 emits light at the first brightness, so that the low beam range 300 is brightly illuminated. The intervals between hatches represent brightness, and the narrower the intervals between hatches, the brighter it is.

[0065] like Figure 3 As shown in (b), when the high beam is on, the range 302 of the high beam is brightly illuminated by the second semiconductor light emitting element 114. At this time, the first semiconductor light emitting element 112 emits light at a second brightness that is darker than the first brightness, so the range 302 of the low beam is brighter than the first brightness. Figure 3 (a) The low beam becomes dim when it is on.

[0066] The above is the operation of the vehicle lamp 100 .

[0067] According to the vehicle lamp 100, when the high beam is on, the second driver module 140 sends the dimming indication signal DIM to the first driver module 120, so that the first driver module 120 can know that it is the high beam lighting period. In addition, the first driver module 120 reduces the first driving current I in response to the dimming indication. DRVL , thereby reducing the amount of light emitted by the first semiconductor light emitting element 102 and suppressing an increase in the total amount of heat generated by the light emitting unit 110 during high beam lighting.

[0068] The vehicle lamp 100 is ideal for commercial vehicles such as trucks. Such vehicle lamps are sometimes fanless for long-term reliability. This embodiment reduces heat generation in the light-emitting unit 110, ensuring reliability even without a fan.

[0069] Figure 4 Show Figure 1 FIG. 1 is a block diagram of an embodiment 100A of a vehicle lamp 100 .

[0070] The first converter controller 124 includes an analog dimming terminal ADIM. The first driving current I DRV1 The target current I REFLThe voltage V of the analog dimming terminal ADIM can be adjusted ADIM The first driving module 120A has a derating circuit 130, which is used as Figure 1 The first interface circuit 126 functions.

[0071] The derating circuit 130 monitors the temperature and reduces the voltage V ADIM Maintained at a certain level, when the temperature exceeds the threshold, as the temperature rises, the voltage V ADIM Reduce (temperature derating).

[0072] The dimming indication signal DIM is input to the derating circuit 130. When the dimming indication signal DIM is valid (eg, high), the derating circuit 130 makes the voltage V ADIM reduce.

[0073] The second driving module 140A includes a linear regulator 160. The linear regulator 160 serves as Figure 1 The second interface circuit 146 functions. The input terminal IN of the linear regulator 160 is connected to the high beam switch SW2, and the output terminal OUT is connected to the derating circuit 130. The linear regulator 160 is supplied with an input voltage V at the input terminal IN. H When it starts, it generates a voltage V that is stabilized at a specified voltage (for example, 5V). LDO The voltage V LDO The dimming instruction signal DIM is supplied to the derating circuit 130 .

[0074] Figure 5 1 is a circuit diagram showing a configuration example of the derating circuit 130 . The derating circuit 130 includes resistors R1 and R2 , a temperature derating circuit 132 , and a dimming circuit 134 .

[0075] Resistors R1 and R2 are connected to the power line V DD The resistor divider circuit is connected in series with the ground line, and the connection node of the resistors R1 and R2 is connected to the analog dimming terminal ADIM of the first converter controller 124A. When the output of the temperature derating circuit 132 and the dimming circuit 134 is high impedance, the voltage V ADIM V DD ×R2 / (R1+R2).

[0076] The temperature derating circuit 132 includes a temperature-sensitive element such as a thermistor, and changes its output according to the temperature. When the temperature is below the threshold, the output of the temperature derating circuit 132 is high impedance and does not affect the analog dimming terminal ADIM. When the temperature is above the threshold, the output impedance of the temperature derating circuit 132 decreases as the temperature increases, absorbing more current. Therefore, as the temperature increases, the voltage V ADIM The lower.

[0077] The dimming circuit 134 receives the dimming indication signal DIM, and in response to the dimming indication signal DIM being valid, the voltage V ADIM For example, the dimming circuit 134 includes a resistor R3, a transistor Q1, and a low-pass filter 136. The dimming instruction signal DIM is input to the substrate of the transistor Q1 through the low-pass filter 136. When the dimming instruction signal DIM is valid, the transistor Q1 is turned on. In this state, since the resistors R2 and R3 are connected in parallel, the voltage V ADIM Become a V DD ×(R2 / / R3) / {(R1+(R2 / / R3)}, V DD × R2 / (R1+R2) is lower. R2 / / R3 represents the combined resistance of R2 and R3 in parallel.

[0078] (Implementation Method 2)

[0079] Figure 6 1 is a block diagram illustrating a second driving module 140B according to Embodiment 2. The second semiconductor light emitting element 114B of the light emitting unit 110B is an LED array including LEDs 116 arranged in a matrix.

[0080] The second lighting circuit 170B includes DC / DC converters 172 and 174 , an LED controller 176 , and a microcontroller 178 .

[0081] The DC / DC converter 172 is a step-up converter that converts the input voltage V H The DC / DC converter 174 is a step-down converter that steps down the output voltage V of the DC / DC converter 172 at the previous stage. M Step down to generate driving voltage V DRVH .

[0082] The LED controller 176 receives the driving voltage V DRVH , according to the control based on the microcontroller 178, multiple LEDs 116 are turned on and off individually.

[0083] The linear regulator 180 is supplied with an input voltage V L When it starts, it generates a 5V power supply voltage V DDThe power supply voltage V DD Supplied to the microcontroller 178 and the like.

[0084] The microcontroller 178 is supplied with a power supply voltage V DD After the microcontroller 178 is started, it supplies an enable signal to the enable terminal EN of the linear regulator 160 to operate the linear regulator 160. As a result, the dimming instruction signal DIM becomes effective.

[0085] Furthermore, after being activated, the microcontroller 178 controls the LED controller 176 so as to form a predetermined high-beam light distribution.

[0086] (Implementation 3)

[0087] Figure 7 This is a block diagram of the second driving module 140C according to Embodiment 3. The basic structure of the second driving module 140C is the same as Figure 6 The second driver module 140B is similar to the second driver module 140B. The difference is that the high beam distribution in the second driver module 140B is fixed. In contrast, the second driver module 140C supports the ADB (Adaptive Driving Beam) function. When the high beam is on, the high beam distribution can be adaptively controlled based on the conditions ahead of the vehicle. For example, if an oncoming vehicle or a preceding vehicle is detected, the high beam distribution can be dimmed or blocked.

[0088] The second driving module 140C includes a transceiver 190. The transceiver 190 is an interface such as a LIN (Local Interconnect Network) or a CAN (Controller Area Network), and receives information necessary for ADB control from the vehicle.

[0089] The microcontroller 178 controls the LED controller 176 based on the information received by the transceiver 190, and individually controls the connection and disconnection of multiple LEDs 116 to control the light distribution of the high beam.

[0090] (Implementation 4)

[0091] Embodiment 4 relates to the indicator function.

[0092] Indicators are installed in vehicles to notify users of abnormalities occurring in the vehicle by lighting them up. Representative examples of indicators are various warning lights incorporated into instrument panels.

[0093] In conventional headlights that use valves, the light goes off when the valve is shut off, allowing the user to clearly know the abnormality. Therefore, in existing headlights, an indicator is not necessary.

[0094] In recent years, LEDs have become the mainstream light source for headlights. LEDs offer the advantage of being able to create more appropriate light distribution by combining multiple LEDs due to their high degree of layout flexibility. However, if a portion of an LED fails to illuminate, while appropriate light distribution may not be achieved, the lamp itself continues to illuminate, and the user may not be aware of the abnormality. Therefore, indicators are required in vehicle lamps equipped with LEDs (UN Regulation R48, Section 6.2.8, of the Agreement on the Unified Provisions Relating to the Licensing of Vehicles under the Agreement on Lighting Devices and Reflectors and on Mounting Devices for Indicators, No. 48).

[0095] When a warning light for notifying of a headlamp abnormality is mounted on the instrument panel, the cost of the vehicle body increases.

[0096] In the fourth embodiment, a description will be given of providing a vehicle lamp that does not require an indicator.

[0097] (Implementation 4)

[0098] Figure 8 1 is a block diagram of a vehicle lamp 100 according to Embodiment 4. The vehicle lamp 100 is a low-beam lamp and includes a light-emitting unit 110 and an LED driver module (LDM) 200 .

[0099] The light-emitting unit 110 includes a first semiconductor light-emitting element 112 for low-beam and a second semiconductor light-emitting element 114 for low-beam. Light emitted by the first and second semiconductor light-emitting elements 112, 114 passes through an optical system (not shown) to form a low-beam light distribution in front of the vehicle. For example, light emitted by the first semiconductor light-emitting element 112 is directed toward the upper portion of the low-beam illumination area, while light emitted by the second semiconductor light-emitting element 114 is directed toward the lower portion of the low-beam illumination area.

[0100] The input terminal IN of the driving module 200 is connected to the power supply 2 via the low beam switch SW1. When the low beam is on, the low beam switch SW1 is turned on and the power supply voltage V is supplied to the input terminal IN. BAT The driving module 200 receives the power supply voltage V supplied to the input terminal IN. BAT That is, the power supply voltage V is supplied to the input voltage IN. BAT This is an instruction to turn on the low beam of the vehicle lamp 100 .

[0101] The first lighting circuit 210 starts operating in response to the low beam lighting instruction, lighting the first semiconductor light emitting element 112. The first lighting circuit 210 has an abnormality detection function, and when an abnormality is detected, the first fault signal FLT1 is activated.

[0102] The second lighting circuit 220 starts operating in response to the low beam lighting instruction, lighting the second semiconductor light emitting element 114. The second lighting circuit 220 has an abnormality detection function, and when an abnormality is detected, the second fault signal FLT2 is activated.

[0103] The first fault signal FLT1 and the second fault signal FLT2 are input to the latch circuit 230. The latch circuit 230 asserts the stop signal STOP when at least one of the first fault signal FLT1 and the second fault signal FLT2 is asserted.

[0104] Preferably, the latch circuit 230 is a timer latch circuit that asserts the stop signal STOP and fixes the stop signal STOP in an asserted state when at least one of the first fault signal FLT1 and the second fault signal FLT2 remains asserted for a predetermined determination time.

[0105] The stop signal STOP is supplied to the first lighting circuit 210 and the second lighting circuit 220. In response to the assertion of the stop signal STOP, the first lighting circuit 210 stops the first driving current I DRV1 The second lighting circuit 220 stops the second driving current I in response to the activation of the stop signal STOP. DRV2 is generated, and the second semiconductor light emitting element 114 is extinguished.

[0106] The first lighting circuit 210 includes a first DC / DC converter 212 and a first converter controller 214. The first DC / DC converter 212 generates a pulse modulation signal S supplied from the first converter controller 214. P1 The first semiconductor light emitting element 112 is switched to supply the first driving current I DRV1 For example, the pulse modulation signal S P1 It can be a pulse width modulation signal or a pulse frequency modulation signal.

[0107] The first DC / DC converter 212 may be a buck converter, a buck-boost converter, or a boost converter. The type of the first DC / DC converter 212 may be selected based on the number of LEDs connected in series that constitute the first semiconductor light emitting element 112 .

[0108] The first converter controller 214 generates a first driving current I DRV1 Close to its target amount I REF1 Generate pulse modulation signal S in the form of P1 , feedback control (constant current control) is performed on the first DC / DC converter 212.

[0109] Furthermore, the first converter controller 214 is configured to detect an abnormality in the first semiconductor light emitting element 112. The type of abnormality or the method of detecting the abnormality is not particularly limited. For example, the first converter controller 214 may monitor the voltage between the two ends of the first semiconductor light emitting element 112 and determine that an abnormality occurs when the voltage deviates from a predetermined range. Alternatively, the first converter controller 214 may monitor the first drive current I DRV1 , without converging to the target quantity I REF1 The first converter controller 214 may also detect a ground or power connection as an abnormality.

[0110] The first converter controller 214 may be formed of a commercially available DC / DC converter controller IC (Integrated Circuit) and its peripheral circuits.

[0111] For example, the controller IC may also have an abnormality detection function and a fault pin for notifying the outside of abnormality detection.

[0112] For example, when the controller IC does not have an abnormality detection function, an abnormality detection circuit may be constructed using discrete components outside the controller IC.

[0113] The controller IC can also use a component with a PWM terminal for PWM dimming. In this case, the peripheral circuit can be configured so that the PWM terminal is fixed low in response to the assertion of the stop signal STOP. Alternatively, a controller IC with an enable terminal can be used, and the peripheral circuit can be configured so that the enable terminal is fixed low in response to the assertion of the stop signal STOP.

[0114] The second lighting circuit 220 includes a second DC / DC converter 222 and a second converter controller 224 , and has the same configuration as the first lighting circuit 210 .

[0115] The above is the structure of the vehicle lamp 100 .

[0116] According to this configuration, all LEDs are turned off when a failure is detected in either the first lighting circuit 210 or the second lighting circuit 220. Therefore, visual indicators are excluded from the mandatory configuration requirements, and indicators are no longer required.

[0117] Figure 9 It shows Figure 8 FIG1 shows an example of a low beam distribution 800 for a vehicle lamp 100A. Low beam distribution 800 includes a main low beam portion 802 and an additional low beam portion 804. Main low beam portion 802 is formed by light emitted by the first semiconductor light emitting element 112. Additional low beam portion 804 is a supplementary light distribution that broadly illuminates the lower and side surfaces of main low beam portion 802 and is formed by light emitted by the second semiconductor light emitting element 114.

[0118] While the embodiments of the present disclosure are described using specific language, such descriptions are intended to assist understanding and are not intended to limit the scope of the present disclosure or the claims. The scope of the present disclosure is determined by the scope of the claims, and therefore, any embodiments, examples, and modifications not described herein are intended to be included within the scope of the present disclosure.

[0119] Industrial applicability

[0120] The present disclosure relates to a vehicle lamp used in automobiles and the like.

[0121] Description of Reference Numerals

[0122] 2…power supply, SW1…low-beam switch, SW2…high-beam switch, 100…vehicle lamp, 110…light-emitting unit, 112…first semiconductor light-emitting element, 114…second semiconductor light-emitting element, 120…first driver module, 122…first DC / DC converter, 124…first converter controller, 126…first interface circuit, 140…second driver module, 150…second lighting circuit, 152…second DC / DC converter, 154…second converter controller, 146…second interface circuit, 130…derating circuit, 160…linear regulator, 132…temperature derating circuit , 134…dimming circuit, 170B, 170C…lighting circuit, 172, 174…DC / DC converter, 176…LED controller, 178…microcontroller, 180…linear regulator, 190…transceiver, 200…driving module, 210…first lighting circuit, 212…first DC / DC converter, 214…first converter controller, 220…second lighting circuit, 222…second DC / DC converter, 224…second converter controller, 230…latch circuit, FLT1…first fault signal, FLT2…second fault signal, STOP…stop signal.

Claims

1. A vehicle lamp, characterized in that: include: The light emitting unit includes a first semiconductor light emitting element for low beam and a second semiconductor light emitting element for high beam, a first driving module, lighting up the first semiconductor light emitting element, and a second driving module, lighting up the second semiconductor light emitting element; The first driving module includes: a first DC / DC converter for supplying a first driving current to the first semiconductor light emitting element, and a first converter controller that feedback-controls the first DC / DC converter in such a manner that the first drive current generated by the first DC / DC converter approaches a first target amount; The second driving module sends a dimming instruction signal to the first driving module in response to the high beam lighting instruction. The first driving module controls the first driving current to be lower than a second target amount that is smaller than the first target amount in response to the dimming indication signal.

2. The vehicle lamp according to claim 1, wherein: The first converter controller has an analog dimming terminal, the first target quantity is based on a dimming voltage generated at the analog dimming terminal, The first driving module further includes a dimming circuit, which reduces the dimming voltage in response to the dimming indication signal.

3. The vehicle lamp according to claim 1 or 2, characterized in that: The second driving module includes a first linear regulator that is activated in response to the high beam lighting instruction, and an output voltage of the first linear regulator is supplied to the first driving module as the dimming instruction signal.

4. The vehicle lamp according to claim 3, characterized in that: Also includes: an interface circuit, receiving a high beam lighting indication; as well as The microcontroller enables the first linear regulator in response to the light-on indication received by the interface circuit.

5. The vehicle lamp according to claim 3, wherein: The high beam lighting instruction is provided as a supply of power supply voltage to the second driving module. The vehicle lamp further comprises: a second linear regulator operating when the power supply voltage is supplied, and The microcontroller is activated when supplied with the output voltage of the second linear regulator, thereby enabling the first linear regulator.

6. The vehicle lamp according to claim 1 or 2, characterized in that: It is fanless.

7. A vehicle lamp, characterized in that: include: The first semiconductor light emitting element for low beam, The second semiconductor light emitting element for low beam, The first lighting circuit lights up the first semiconductor light emitting element and enables a first fault signal when an abnormality is detected. a second lighting circuit that lights up the second semiconductor light emitting element and, when an abnormality is detected, validates a second fault signal; and a latch circuit, which enables a stop signal when at least one of the first fault signal and the second fault signal is valid; The first lighting circuit and the second lighting circuit turn off the first semiconductor light emitting element and the second semiconductor light emitting element in response to the assertion of the stop signal.

8. The vehicle lamp according to claim 7, characterized in that: The first lighting circuit determines that the voltage between both ends of the first semiconductor light emitting element is abnormal when it deviates from a normal range. The second lighting circuit determines that an abnormality has occurred when the voltage between both ends of the second semiconductor light emitting element deviates from a normal range.

9. The vehicle lamp according to claim 7 or 8, characterized in that: The first lighting circuit and the second lighting circuit respectively include: DC / DC converter; and The controller circuit performs feedback control on the DC / DC converter so that an output current of the DC / DC converter approaches a target current.

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