Vehicle lighting fixture and lamp control module

Abstract

To provide a vehicle lamp fitting capable of setting derating characteristics flexibly.SOLUTION: A first drive circuit 330 supplies to a first light source 202 a first drive current ILED1 stabilized to a first target current IREF1. An A / D converter 306 receives at least one electric signal indicating a state of a vehicle lamp fitting 200, and generates at least one detection value corresponding to the at least one electric signal. A non-volatile memory 308 stores (i) a base current value IBASE1 of the first drive current ILED1, and (ii) at least one parameter group prescribing derating characteristics of the first light source 202 based on each of at least one detection value. A signal processing device 400 receives at least one detection value, and calculates the first target current IREF1 according to the base current value IBASE1 and the at least one parameter group by executing a software program.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a lamp for use in a vehicle such as an automobile. [Background technology]

[0002] In recent years, vehicle lighting fixtures have become more and more sophisticated, and headlamps are now equipped with multiple lamps with different functions, such as low beam, high beam, turn signal lamp, position lamp, and daytime running lamp, and it is necessary to control the light sources of these multiple lamps to emit light at an appropriate brightness in response to control signals from the vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-057468 A Summary of the Invention [Problem to be solved by the invention]

[0004] The inside of a headlamp can become extremely hot. If the electrical circuits inside the headlamp continue to operate in a high-temperature state, the lifespan of the components will be shortened. For this reason, headlamps are equipped with a temperature sensor and a temperature derating function that reduces the drive current supplied to the semiconductor light-emitting element when the temperature rises.

[0005] The temperature derating characteristics need to be optimized for each headlamp depending on factors such as the components used in the headlamp and the characteristics of the vehicle in which the headlamp is installed.

[0006] Conventionally, it has been necessary to design a headlamp by modifying a software program or modifying hardware (for example, circuit constants) to conform to the specifications of the headlamp.

[0007] The present disclosure has been made in view of the above problems, and an exemplary purpose of an embodiment of the present disclosure is to provide a vehicle lamp that allows flexibly setting of derating characteristics. [Means for solving the problem]

[0008] An aspect of the present disclosure relates to a vehicle lamp. The vehicle lamp includes a first light source and a first target current I REF1 a first drive circuit that supplies a first light source with a first drive current stabilized to the first light source; an A / D converter that receives at least one electrical signal indicating a state of the vehicle lamp and generates at least one detection value corresponding to the at least one electrical signal; and (i) a base current value I BASE1 (ii) a non-volatile memory for storing at least one parameter group defining a derating characteristic of the first light source based on each of the at least one detection value; and a software program for receiving the at least one detection value and determining a base current value I BASE1 and a first target current I in response to at least one parameter group. REF1 and a signal processor for calculating:

[0009] An aspect of the present disclosure relates to a lamp control module for use in a vehicle lamp having a first light source. The lamp control module controls a first target current I REF1 a first drive circuit that supplies a first light source with a first drive current stabilized to the first light source; an A / D converter that receives at least one electrical signal indicating a state of the vehicle lamp and generates at least one detection value corresponding to the at least one electrical signal; and (i) a base current value I BASE1 (ii) a non-volatile memory for storing at least one parameter group defining a derating characteristic of the first light source based on each of the at least one detection value; and a software program for receiving the at least one detection value and determining a base current value I BASE1 and a first target current I in response to at least one parameter group. REF1 and a signal processor for calculating:

[0010] Any combination of the above components or mutual substitution of the components or expressions of the present invention between methods, devices, systems, etc. are also valid as aspects of the present invention. Effect of the Invention

[0011] According to certain aspects of the present disclosure, the derating characteristics can be flexibly designed. [Brief description of the drawings]

[0012] [Figure 1] 1 is a block diagram of a lighting system according to a first embodiment. [Diagram 2] 2(a) and (b) are diagrams showing the relationship between the derating characteristic and the parameter group PRM in the control example 1. [Diagram 3] 3(a) and (b) are diagrams showing the relationship between the derating characteristics and the parameter group PRM. [Figure 4] FIG. 11 is a block diagram of a lighting system according to a second embodiment. [Diagram 5] FIG. 2 is a block diagram showing a specific configuration example of a vehicle lamp. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] (Overview of the embodiment) A summary of some exemplary embodiments of the present disclosure is provided. This summary is intended to provide a basic understanding of one or more embodiments as a prelude to the detailed description that follows, and is not intended to limit the scope of the invention or disclosure. Additionally, this summary is not intended to be a comprehensive overview of all possible embodiments, nor does it limit essential elements of the embodiments. For convenience, the term "one embodiment" may be used to refer to one or more embodiments disclosed herein.

[0014] A vehicle lamp according to an embodiment includes a first light source and a lamp control module. The lamp control module controls a first target current I REF1 a first drive circuit that supplies a first light source with a first drive current stabilized to the first light source; an A / D converter that receives at least one electrical signal indicating a state of the vehicle lamp and generates at least one detection value corresponding to the at least one electrical signal; and (i) a base current value I BASE1 (ii) a non-volatile memory for storing at least one parameter group defining a derating characteristic of the first light source based on each of the at least one detection value; and a software program for receiving the at least one detection value and determining a base current value I BASE1 and a first target current I in response to at least one parameter group. REF1 and a signal processor for calculating:

[0015] According to this configuration, it is possible to change the derating characteristics according to the product specifications by changing the values ​​of the parameter group written in the non-volatile memory without changing the software program, circuit constants, etc. This provides the effect of shortening the design period and reducing the design cost.

[0016] In one embodiment, the at least one detection value is a temperature detection value T based on an output of a first temperature sensor and a voltage detection value V based on an input voltage of the first driving circuit. DD The parameter group related to the temperature detection value T may include a derating start temperature T S , derating end temperature T E , the decrease rate α may be included. DD The parameters for the derating start voltage V S , derating end voltage V E , the decrease rate β. The signal processing device may calculate the amount of current I after derating with respect to the temperature detection value T. TEMP_DER of, I TEMP_DER =I BASE1 (T <T S ) I TEMP_DER =I BASE1 {1 - α(T - T S )} (T S < T < T E ) I TEMP_DER =I BASE1 {1 - α(T E - T S )} (T E < T) It may be calculated based on this. Further, the signal processing device may use the current value I DD after dilation with respect to the voltage detection value V VOLT_DER as I VOLT_DER =I BASE1 (V DD < V S ) I VOLT_DER =I BASE1 {1 - β(V DD - V S )} (V S < V DD < V E ) I VOLT_DER =I BASE1 {1 - β(V E - V S )} (V E < V DD ) It may be calculated based on this. The signal processing device may use the smaller of the current values I TEMP_DER and I VOLT_DER as the first target current I REF1 .

[0017] The parameter group related to the temperature detection value T may further include the abnormal determination temperature T MAX . The signal processing device may set I MAX = 0 in the range where T TEMP_DER < T.

[0018] In one embodiment, at least one detection value may include the temperature detection value T1 based on the output of the first temperature sensor and the temperature detection value T2 based on the output of the second temperature sensor. The parameter group related to the temperature detection value T1 includes the dilation start temperature T S1 , the dilation end temperature TE1 , the decrease rate α1. The parameter group related to the temperature detection value T2 may include the derating start temperature T S2 , derating end temperature T E2 , the decrease rate α2. The signal processing device may calculate the amount of current I after derating with respect to the temperature detection value T1. TEMP_DER1 of, I TEMP_DER1 =I BASE1 (T1 <T S1 ) I TEMP_DER1 =I BASE1 {1-α1(T1-T S1 )} (T S1 <T1<T E1 ) I TEMP_DER1 =I BASE1 {1-α1(T E1 -T S1 )} (T E1 <T1) The signal processing device may calculate the amount of current I after derating with respect to the temperature detection value T2. TEMP_DER2 of, I TEMP_DER2 =I BASE1 (T2 <T S2 ) I TEMP_DER2 =I BASE1 {1-α2(T2-T S2 )} (T S2 <T2<T E2 ) I TEMP_DER2 =I BASE1 {1-α2(T E2 -T S2 )} (T E2 <T2) The signal processor may calculate the current I TEMP_DER1 and I TEMP_DER2 The smaller of these is the first target current I REF1 It is also possible to use the following.

[0019] In one embodiment, the at least one detection value is a temperature detection value T1 based on an output of a first temperature sensor, a temperature detection value T2 based on an output of a second temperature sensor, and a voltage detection value V based on an input voltage of the first driving circuit.DD The parameter group related to the temperature detection value T1 may include a derating start temperature T S1 , derating end temperature T E1 , the decrease rate α1. The parameter group related to the temperature detection value T2 may include the derating start temperature T S2 , derating end temperature T E2 , the decrease rate α2 may be included. DD The parameters related to the derating start voltage V S , derating end voltage V E , the decrease rate β. The signal processing device calculates the amount of current I after derating with respect to the temperature detection value T1. TEMP_DER1 of, I TEMP_DER1 =I BASE1 (T1 <T S1 ) I TEMP_DER1 =I BASE1 {1-α1(T1-T S1 )} (T S1 <T1<T E1 ) I TEMP_DER1 =I BASE1 {1-α1(T E1 -T S1 )} (T E1 <T1) The signal processing device may calculate the amount of current I after derating with respect to the temperature detection value T2. TEMP_DER2 of, I TEMP_DER2 =I BASE1 (T2 <T S2 ) I TEMP_DER2 =I BASE1 {1-α2(T2-T S2 )} (T S2 <T2<T E2 ) I TEMP_DER2 =I BASE1 {1-α2(T E2 -T S2 )} (T E2 <T2) The signal processing device may calculate the voltage detection value V DDThe current I after dilation related to VOLT_DER is I VOLT_DER =I BASE1 (V DD <V S ) I VOLT_DER =I BASE1 {1-β(V DD -V S )} (V S <V DD <V E ) I VOLT_DER =I BASE1 {1-β(V E -V S )} (V E <V DD ) It may be calculated based on. The signal processing device is the current I TEMP_DER1 、I TEMP_DER2 、I VOLT_DER The smallest one among them may be used as the first target current I REF1 .

[0020] The parameter group related to the temperature detection value T1 further includes the abnormal determination temperature T MAX1 , and the parameter group related to the temperature detection value T2 may further include the abnormal determination temperature T MAX2 . The signal processing device may set I MAX1 =0 in the range of T TEMP_DER1 <T1, and set I MAX2 =0 in the range of T TEMP_DER2 <T2.

[0021] In one embodiment, the first drive circuit, the A / D converter, the non-volatile memory, and the signal processing device may be configured as the same module. The first temperature sensor may be provided inside the module, and the second temperature sensor may be provided outside the module. By monitoring the temperatures inside and outside the module and performing dilation control based on different parameters, the dilation characteristics can be designed more flexibly.

[0022] In one embodiment, the vehicle lamp may further include a second light source. The lamp control module controls a second target current I REF2 The non-volatile memory may further include a second drive circuit that supplies a second drive current stabilized to the second light source. BASE2 The signal processor further stores the base current value I BASE2 and a second target current I in response to at least one parameter group. REF2 The control can be simplified by sharing a parameter group for each detection value among a plurality of light sources.

[0023] (Embodiment) The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components, parts, and processes shown in each drawing are given the same reference numerals, and duplicated descriptions are omitted as appropriate. In addition, the embodiments are illustrative rather than limiting the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

[0024] In this specification, "a state in which component A is connected to component B" includes not only a case in which component A and component B are directly physically connected to each other, but also a case in which component A and component B are indirectly connected to each other via other components that do not substantially affect the electrical connection state between them or that do not impair the function or effect achieved by their combination.

[0025] Similarly, "a state in which component C is provided between components A and B" includes not only the case in which components A and C, or components B and C, are directly connected to each other, but also the case in which they are indirectly connected to each other via other components that do not substantially affect the electrical connection between them or that do not impair the functions or effects achieved by their combination.

[0026] (Embodiment 1) 1 is a block diagram of a lighting system 100 according to embodiment 1. The lighting system 100 includes a vehicle 110 and a vehicle lamp (headlamp) 200. The vehicle 110 includes an ECU (Electronic Control Unit) on the vehicle side, a battery, switches for each lamp, and the like.

[0027] The vehicle lamp 200 has functions such as low beam (Lo), high beam (Hi), daytime running lamp (DRL), position lamp (POS), turn signal lamp (TURN), etc. Fig. 1 shows only one of the configurations.

[0028] The vehicle lamp 200 includes a first light source 202 and a lamp control module 300. The first light source 202 is one of a low beam (Lo), a high beam (Hi), a daytime running lamp (DRL), and a position lamp (POS).

[0029] The first light source 202 can be composed of one semiconductor light emitting element, or multiple semiconductor light emitting elements connected in series and / or parallel. Examples of semiconductor light emitting elements include white LEDs (light emitting diodes), laser diodes, and organic EL (Electro Luminescence) elements. In FIG. 1, the first light source 202 is an LED bar (LED string) made up of multiple LEDs connected in series. The number of LEDs constituting the first light source 202 may be determined in consideration of the required brightness and design, and is not particularly limited.

[0030] A power supply voltage +B is supplied to the vehicular lamp 200 from the vehicle 110 via a power supply line 102 .

[0031] A first lighting request REQ1 instructing the vehicular lamp 200 to turn on or off the first light source 202 is supplied from the vehicle 110 to the vehicular lamp 200 via the vehicle bus 106. The type of the vehicle bus is not particularly limited, and a controller area network (CAN) or a local interconnect network (LIN) can be used.

[0032] The lamp control module 300 includes an A / D converter 306, a non-volatile memory 308, a bus interface circuit 320, and a first drive circuit 330. The main components of the lamp control module 300 are housed in a single housing and modularized.

[0033] The bus interface circuit 320 is a transceiver capable of two-way communication with the vehicle 110 via the vehicle bus 106. The data received by the bus interface circuit 320 includes a first lighting request REQ1.

[0034] The first drive circuit 330 outputs a first target current I REF1 The drive current I LED1 and supplies the first light source 202 to the first drive circuit 330. The first drive circuit 330 generates a first target current I REF1 is configured to be configurable.

[0035] The signal processing device 400 includes a processor capable of executing a software program. The signal processing device 400 can be configured with a microcontroller, a CPU (Central Processing Unit), a DSP (Digital Signal Processor), or the like.

[0036] The A / D converter 306 outputs at least one (n≧1) electrical signal Vs1 to Vs n At least one of the electrical signals Vs1 to Vs n At least one detection value Ds1 to Ds n As described later, the certain electrical signal may be the output of a temperature sensor such as a thermistor, or may be the input voltage (power supply voltage) of the first drive circuit 330.

[0037] The non-volatile memory 308 stores the first driving current I LED1 The base current value I BASE1 , at least one detection value Ds1 to Ds nAt least one parameter group PRM1 to PRM2 that defines the derating characteristics of the first light source 202 based on each of the parameters. n The i-th (1≦i≦n) parameter group PRM i is the corresponding i-th detection value Ds i The non-volatile memory 308 may be built in the same package as the signal processing device 400.

[0038] The signal processing device 400 detects at least one of the detection values ​​Ds1 to Ds n The base current value I BASE1 and at least one parameter group PRM1 to PRM n The first target current I REF1 Calculate.

[0039] For example, the signal processing device 400 detects each detection value Ds i (i=1~n), the current after derating I DERi Then, calculate the current amount after derating I DER1 ~I DERn The smallest current amount is the first target current I REF1 It is also possible to use the following. I REF1 =min(I DER1 ,I DER2 ,…,I DERn ) min() is a function that selects the minimum value of multiple elements.

[0040] In response to the lighting request REQ1, the signal processing device 400 enables the first driving circuit 330. Then, the first target current I REF1 The control signal CNT1 including the following is provided to the first driving circuit 330.

[0041] The above is the configuration of the vehicular lamp 200. According to this vehicular lamp 200, the derating characteristics can be changed according to the product specifications by changing the values ​​of the parameter group PRM written in the non-volatile memory 308 without changing the software program, circuit constants, etc. This provides the effects of shortening the design period and reducing the design costs.

[0042] Next, a specific example of the derating control will be described.

[0043] <Control example 1> In control example 1, the signal processing device 400 performs derating based on n=2 detection values ​​Ds1 and Ds2. The detection value Ds1 is a temperature detection value T based on the output of the temperature sensor, and the detection value Ds2 is a voltage detection value V based on the input voltage of the first drive circuit 330. DD It is.

[0044] The parameter group describing the derating characteristic will be described. FIGS. 2(a) and (b) are diagrams showing the relationship between the derating characteristic and the parameter group PRM in control example 1. FIG. 2(a) shows the temperature derating characteristic based on a detection value Ds1 representing temperature T. The horizontal axis shows the detection value (i.e., temperature T) based on the output of a temperature sensor (e.g., a thermistor), and the vertical axis shows the amount of current I after temperature derating for the detection value Ds1. TEMP_DER In this example, the parameter set PRM1 includes four parameters: Derating start temperature T S Derating end temperature T E Decrease rate α Abnormality judgment temperature T MAX The temperature derating characteristics are specified by four parameters, including the current I TEMP_DER is expressed by the following formula: I TEMP_DER =I BASE1 (T <T S ) I TEMP_DER =IBASE1 {1-α(TT S )} (T S <T<T E ) I TEMP_DER =I BASE1 {1-α(T E -T S )} (T E <T<T MAX ) I TEMP_DER =0 (T MAX <T)

[0045] FIG. 2(b) shows the voltage derating characteristic based on the detection value Ds2 representing the voltage. The horizontal axis represents the detection value V DD The vertical axis represents the amount of current I after voltage derating for the detection value Ds2. VOLT_DER The parameter set PRM2 consists of four parameters, namely, Derating start voltage V S Derating end voltage V E Decrease rate β Abnormality judgment temperature V MAX The voltage derating characteristics are specified by four parameters, including the current I VOLT_DER is expressed by the following formula: I VOLT_DER =I BASE1 (V DD <V S ) I VOLT_DER =I BASE1 {1-β(V DD -V S )} (V S <V DD <V E ) I VOLT_DER =I BASE1 {1-β(V E -V S )} (V E <V DD <V MAX ) I VOLT_DER =0 (V MAX <VDD )

[0046] The target current I after considering both temperature and voltage REF1 teeth, I REF1 =min(I TEMP_DER ,I VOLT_DER ) It becomes.

[0047] <Control example 2> In control example 2, the signal processing device 400 performs derating based on n=2 detected values ​​Ds1 and Ds2. The detected value Ds1 is a temperature detected value T1 based on the output of a first temperature sensor, and the detected value Ds2 is a temperature detected value T2 based on the output of a second temperature sensor.

[0048] The parameter group describing the derating characteristic will be described. FIGS. 3(a) and (b) are diagrams showing the relationship between the derating characteristic and the parameter group PRM. FIG. 3(a) shows the temperature derating characteristic based on the detection value Ds1 representing the temperature T1. The parameter group PRM1 includes four parameters, namely Derating start temperature T S1 Derating end temperature T E1 Decrease rate α1 Abnormality judgment temperature T MAX1 The temperature derating characteristics are specified by four parameters, including the current I TEMP_DER1 is expressed by the following formula: I TEMP_DER1 =I BASE1 (T1 <T S1 ) I TEMP_DER1 =I BASE1 {1-α1(T1-T S1 )} (T S1 <T1<T E1 ) I TEMP_DER1 =I BASE1 {1-α1(T E1 -T S1 )} (T E1 <T1<TMAX1 ) I TEMP_DER1 =0 (T MAX1 <T1)

[0049] FIG. 3(b) shows the temperature derating characteristic based on the detection value Ds2 representing the temperature T2. The parameter group PRM2 includes four parameters, namely: Derating start temperature T S2 Derating end temperature T E2 Decrease rate α2 Abnormality judgment temperature T MAX2 The temperature derating characteristics are specified by four parameters, including the current I TEMP_DER2 is expressed by the following formula: I TEMP_DER2 =I BASE1 (T2 <T S2 ) I TEMP_DER2 =I BASE1 {1-α(T2-T S2 )} (T S2 <T2<T E2 ) I TEMP_DER2 =I BASE1 {1-α2(T E2 -T S2 )} (T E2 <T2<T MAX2 ) I TEMP_DER2 =0 (T MAX2 <T2)

[0050] The target current I after considering both temperatures T1 and T2 REF1 teeth, I REF1 =min(I TEMP_DER1 ,I TEMP_DER2 ) It becomes.

[0051] <Control example 3> In the control example 3, the signal processing device 400 performs derating based on n=3 detection values ​​Ds1 to Ds3. The detection value Ds1 is a temperature detection value T1 based on the output of the first temperature sensor, the detection value Ds2 is a temperature detection value T2 based on the output of the second temperature sensor, and the detection value Ds3 is a voltage detection value V DD The three detection values ​​T1, T2, and V DD Three parameter groups are defined corresponding to the three current amounts I TEMP_DER1 ,I TEMP_DER2 ,I VOLT_DER Calculate the minimum of them, min(I TEMP_DER1 ,I TEMP_DER2 ,I VOLT_DER ) to the first target current I REF1 Let us assume that.

[0052] (Embodiment 2) In the first embodiment, the derating control for one light source has been described, but the present technology is not limited thereto and can also be applied to the derating control for two or more light sources.

[0053] 4 is a block diagram of a lighting system 100 according to a second embodiment. The configuration of a vehicle lamp 200 will be described, focusing on differences from the first embodiment. The vehicle lamp 200 includes a first light source 202, a second light source 204, and a lamp control module 300. The first light source 202 is one of a low beam (Lo), a high beam (Hi), a daytime running lamp (DRL), and a position lamp (POS), and the second light source 204 can be another one of the light sources or a turn signal lamp.

[0054] A first lighting request REQ1 instructing to turn on / off the first light source 202 and a second lighting request REQ2 instructing to turn on / off the second light source 204 are supplied to the vehicular lamp 200 from the vehicle 110 via the vehicle bus 106.

[0055] The lamp control module 300 includes an A / D converter 306 , a non-volatile memory 308 , a bus interface circuit 320 , a first drive circuit 330 , and a second drive circuit 340 .

[0056] The bus interface circuit 320 is a transceiver capable of two-way communication with the vehicle 110 via the vehicle bus 106. The data received by the bus interface circuit 320 includes a first lighting request REQ1 and a second lighting request REQ2.

[0057] The first drive circuit 330 outputs a first target current I REF1 The drive current I LED1 and supplies the first light source 202 to the first driving circuit 330. The first driving circuit 330 generates a first target current I REF1 is configured to be configurable.

[0058] The second drive circuit 340 outputs a second target current I REF2 The drive current I LED2 and supplies it to the second light source 204. The second drive circuit 340 generates a second target current I REF2 is configured to be configurable.

[0059] In response to the lighting request REQ1, the signal processing device 400 enables the first driving circuit 330. Then, the first target current I REF1 The control signal CNT1 including the above is provided to the first drive circuit 330. In addition, in response to the lighting request REQ2, the second drive circuit 340 is enabled. Then, the second target current I REF2 The control signal CNT2 including the following is provided to the second driving circuit 340.

[0060] The non-volatile memory 308 stores the first driving current I LED1 The base current value I BASE1 , the second drive current I LED2 The base current value I BASE2 , at least one detection value Ds1 to Ds nAt least one parameter group PRM1 to PRM2 that specifies the derating characteristics based on each n The i-th (1≦i≦n) parameter group PRM i is the corresponding i-th detection value Ds i This specifies the derating characteristics based on the above.

[0061] In this embodiment, there are a plurality of parameter groups PRM1 to PRM n is shared by the derating control of the two light sources (drive current). n The base current value I BASE1 and at least one parameter group PRM1 to PRM n The first target current I REF1 Furthermore, the signal processing device 400 calculates at least one of the detection values ​​Ds1 to Ds n The base current value I BASE2 and at least one parameter group PRM1 to PRM n Depending on the second target current I REF2 Calculate.

[0062] An example of derating control in the second embodiment will be described.

[0063] <Control Example 4> In the control example 4, the signal processing device 400 performs derating based on n=2 detection values ​​Ds1 and Ds2. The detection value Ds1 is a temperature detection value T based on the output of a temperature sensor, and the detection value Ds2 is a voltage detection value V DD It is.

[0064] The parameter group describing the derating characteristics is as described in Control Example 1. The first driving current I after derating LED1 The amount of current I 1_TEMP_DER is expressed by the following formula: I 1_TEMP_DER =I BASE1 (T <TS ) I 1_TEMP_DER =I BASE1 {1-α(TT S )} (T S <T<T E ) I 1_TEMP_DER =I BASE1 {1-α(T E -T S )} (T E <T<T MAX ) I 1_TEMP_DER =0 (T MAX <T)

[0065] Current after derating I 1_VOLT_DER is expressed by the following formula: I 1_VOLT_DER =I BASE1 (V DD <V S ) I 1_VOLT_DER =I BASE1 {1-β(V DD -V S )} (V S <V DD <V E ) I 1_VOLT_DER =I BASE1 {1-β(V E -V S )} (V E <V DD <V MAX ) I 1_VOLT_DER =0 (V MAX <V DD )

[0066] The first target current I after considering both temperature and power supply voltage REF1 teeth, I REF1 =min(I 1_TEMP_DER ,I 1_VOLT_DER ) It becomes.

[0067] Second drive current I after temperature derating LED2 The amount of current I 2_TEMP_DER is expressed by the following formula: I 2_TEMP_DER =I BASE2 (T <T S ) I 2_TEMP_DER =I BASE2 {1-α(TT S )} (T S <T<T E ) I 2_TEMP_DER =I BASE2 {1-α(T E -T S )} (T E <T<T MAX ) I 2_TEMP_DER =0 (T MAX <T)

[0068] Current flow after voltage derating I 2_VOLT_DER is expressed by the following formula: I 2_VOLT_DER =I BASE2 (V DD <V S ) I 2_VOLT_DER =I BASE2 {1-β(V DD -V S )} (V S <V DD <V E ) I 2_VOLT_DER =I BASE2 {1-β(V E -V S )} (V E <V DD <V MAX ) I 2_VOLT_DER =0 (V MAX <V DD )

[0069] The second target current I after considering both temperature and supply voltage REF2 teeth, I REF2 =min(I 2_TEMP_DER ,I 2_VOLT_DER ) It becomes.

[0070] <Control Example 5> In control example 5, the signal processing device 400 performs derating based on n=2 detected values ​​Ds1 and Ds2. The detected value Ds1 is a detected temperature value T1 based on the output of a first temperature sensor, and the detected value Ds2 is a detected temperature value T2 based on the output of a second temperature sensor.

[0071] The signal processing device 400 calculates the following values ​​related to the derating of the first light source 202: I 1_TEMP_DER1 =I BASE1 (T1 <T S1 ) I 1_TEMP_DER1 =I BASE1 {1-α1(T1-T S1 )} (T S1 <T1<T E1 ) I 1_TEMP_DER1 =I BASE1 {1-α1(T E1 -T S1 )} (T E1 <T1<T MAX1 ) I 1_TEMP_DER1 =0 (T MAX1 <T1) I 1_TEMP_DER2 =I BASE1 (T2 <T S2 ) I 1_TEMP_DER2 =I BASE1 {1-α(T2-T S2 )} (T S2 <T2<T E2 ) I 1_TEMP_DER2 =I BASE1 {1-α2(T E2 -T S2 )} (T E2 <T2<T MAX2 ) I 1_TEMP_DER2 =0 (T MAX2 <T2)

[0072] The target current I after considering both temperatures T1 and T2 REF1 teeth, I REF1 =min(I 1_TEMP_DER1 ,I 1_TEMP_DER2 ) It becomes.

[0073] Similarly, the signal processor 400 calculates the following values ​​related to the derating of the second light source 204: I 2_TEMP_DER1 =I BASE2 (T1 <T S1 ) I 2_TEMP_DER1 =I BASE2 {1-α1(T1-T S1 )} (T S1 <T1<T E1 ) I 2_TEMP_DER1 =I BASE2 {1-α1(T E1 -T S1 )} (T E1 <T1<T MAX1 ) I 2_TEMP_DER1 =0 (T MAX1 <T1) I 2_TEMP_DER2 =I BASE2 (T2 <T S2 ) I 2_TEMP_DER2 =I BASE2 {1-α(T2-T S2 )} (T S2 <T2<T E2 ) I 2_TEMP_DER2 =I BASE2 {1-α2(T E2 -T S2 )} (T E2 <T2<T MAX2 ) I 2_TEMP_DER2 =0 (T MAX2 <T2)

[0074] The target current I after considering both temperatures T1 and T2 REF2 teeth, I REF2 =min(I 2_TEMP_DER1 ,I 2_TEMP_DER2 ) It becomes.

[0075] <Control Example 6> In control example 6, similarly to control example 3, the signal processing device 400 performs derating based on n=3 detection values ​​Ds1 to Ds3. The detection value Ds1 is a temperature detection value T1 based on the output of the first temperature sensor, the detection value Ds2 is a temperature detection value T2 based on the output of the second temperature sensor, and the detection value Ds3 is a voltage detection value V DD It is.

[0076] The signal processing device 400 detects three current amounts I 1_TEMP_DER1 ,I 1_TEMP_DER2 ,I 1_VOLT_DER Calculate the minimum of them, min(I 1_TEMP_DER1 ,I 1_TEMP_DER2 ,I 1_VOLT_DER ) to the first target current I REF1 In addition, the signal processing device 400A calculates three current amounts I 2_TEMP_DER1 ,I 2_TEMP_DER2 ,I 2_VOLT_DER Calculate the minimum of them, min(I 2_TEMP_DER1 ,I 2_TEMP_DER2 ,I 2_VOLT_DER ) to the second target current I REF2 Let us assume that.

[0077] Next, a more specific configuration example of the vehicle lamp 200 will be described.

[0078] 5 is a block diagram showing a specific example of the configuration of the vehicle lamp 200A. The vehicle lamp 200A includes a lamp control module 300A and the first light source 202 to the fifth light source 210. As described above, the first light source 202 is used as a turn signal lamp, and the second light source 204 is used as both a DRL and a position lamp. The third light source 206 is used as a low beam, the fourth light source 208 is used as a high beam, and the fifth light source 210 is used as a S.M. It is a light source for.

[0079] The voltages and signals applied to the vehicle lamp 200A will be described. +BLCM: Main power supply for vehicle lighting fixtures 200A (12V or 24V) +VBU: CAN-H, CAN-L: Vehicle bus IG1: Ignition status HL_BU: TURN_SYNC: Turn sync signal

[0080] The power supply circuit 302 receives the voltage VBU and supplies a power supply voltage V DD Generates the power supply voltage V DD is provided to the microcontroller 390 and other circuits.

[0081] The protection circuit 305 includes a diode for preventing reverse connection and a Zener diode for surge protection, and protects the vehicular lamp 200A from the main power supply voltage +BLCM.

[0082] The power supply circuit 304 is a step-up DC / DC converter that steps up the power supply voltage +BLCM from the vehicle to a high power supply voltage V DDH occurs.

[0083] The thermistors 220, 222 are provided to monitor the temperatures of the third light source 206 and the second light source 204. In addition, a thermistor 224 is provided on the circuit board of the lamp control module 300A.

[0084] The A / D converter 306 converts the voltages and currents of multiple nodes of the lamp control module 300A and the voltage of the thermistor into digital signals. In this example, one of the inputs to the A / D converter 306 is the output voltage of the power supply circuit 304, i.e., the input voltages of the first drive circuit 330 and the second drive circuit 340. The output ADC_OUT of the A / D converter 306 is supplied to a microcontroller 390. The microcontroller 390 incorporates the above-mentioned signal processing device 400 and non-volatile memory 308. The microcontroller 390 may incorporate the A / D converter 306.

[0085] The input interface circuit 310 receives the turn synchronization signal TURN_SYNC from the vehicle 110 via the direct line 104. The turn synchronization signal TURN_SYNC is a signal that instructs the turn signal lamp to blink, and when the turn signal lamp blinks, it becomes a pulse signal that alternates between high and low levels at a predetermined cycle, with the high section corresponding to lighting and the low section corresponding to extinguishing. When the turn signal lamp is not blinking (extinguished), the turn synchronization signal TURN_SYNC is fixed to low. The input interface circuit 310 may be a simple buffer, and shapes the turn synchronization signal TURN_SYNC.

[0086] (Turn signal lamp) The first drive circuit 330 includes a constant current output step-down DC / DC converter 332 and outputs a drive current I LED1 The step-down DC / DC converter 332 is supplied with an enable signal EN_BUCK1 and a dimming signal CURRENT_PWM1 as the control signal CNT1. The step-down DC / DC converter 332 is in an operating state when the enable signal EN_BUCK1 is asserted (for example, high), and generates a drive current I LED1 The dimming signal CURRENT_PWM1 is a PWM signal, and the controller IC of the step-down DC / DC converter 332 detects the duty cycle of the dimming signal CURRENT_PWM1 and generates a driving current I LED1 (analog dimming). In other words, the driving current I LED1 Target value I REF1 is set according to the duty cycle of the dimming signal CURRENT_PWM1. To blink the first light source 202 as described above, the signal processing device 400 switches the enable signal EN_BUCK1 according to the turn synchronization signal TURN_SYNC.

[0087] The DC / DC converter 332 transmits the fail information and the diagnostic information DC1_Diag to the signal processing device 400.

[0088] (DRL and position lamps) In this embodiment, the second light source 204 and the third light source 206 are connected in series. The light sources 204 and 206 are driven by a common step-down DC / DC converter 342 and two bypass switches 344 and 354. The second light source 204 is driven by a second drive circuit 340 which is a combination of the step-down DC / DC converter 342 and the bypass switch 344.

[0089] The enable signal EN_BUCK2 and the dimming signal CURRENT_PWM2 supplied to the step-down DC / DC converter 342, and the PWM signal DRL_PWM supplied to the bypass switch 344 correspond to the above-mentioned control signal CNT2.

[0090] The step-down DC / DC converter 342 is in an operating state when the enable signal EN_BUCK2 is asserted (for example, high), and outputs a drive current I DRV The dimming signal CURRENT_PWM2 is a PWM signal, and the controller IC of the step-down DC / DC converter 342 generates a driving current I according to the duty cycle of the dimming signal CURRENT_PWM2. DRV The amount of current is changed (analog dimming).

[0091] The bypass switch 344 is turned on and off by a PWM signal DRL_PWM. During the period when the bypass switch 344 is off, the drive current I DRV is supplied to the second light source 204, and during the period when the bypass switch 344 is on, the driving current I DRV is not supplied to the second light source 204. The signal processing device 400 changes the PWM signal DRL_PWM to control the drive current I LED2 By changing the average value of the second light source 204, the effective brightness of the second light source 204 can be changed.

[0092] For example, the signal processing device 400 changes the duty cycle of the PWM signal DRL_PWM in accordance with the value VAL of the table, thereby changing the luminance of the second light source 204 and switching between the functions of the DRL and the position lamp.

[0093] (Low beam) The combination of the step-down DC / DC converter 342 and the bypass switch 354 is understood to be a third drive circuit 350 that drives the third light source 206. The bypass switch 354 is controlled to be turned on and off in response to the Lo_PWM signal.

[0094] The DC / DC converter 342 transmits the fail information and the diagnostic information DC2_Diag to the signal processing device 400.

[0095] (High beam) The fourth drive circuit 360 that drives the fourth light source 208 includes a step-down DC / DC converter 362. The step-down DC / DC converter 362 is in an operating state when the enable signal EN_BUCK3 is asserted (for example, high), and outputs a drive current I LED4 The dimming signal CURRENT_PWM4 is a PWM signal, and the controller IC of the step-down DC / DC converter 362 generates a driving current I according to the duty cycle of the dimming signal CURRENT_PWM4. LED4 The amount of current is changed (analog dimming).

[0096] The high beam may be an ADB (Adaptive Driving Beam) lamp. In this case, the multiple LEDs constituting the fourth light source 208 for high beam may be configured so that they can be individually controlled to be turned on and off. Specifically, a bypass switch may be provided for each LED chip, and the bypass switch parallel to the LED corresponding to the light-blocking region may be controlled to be turned on.

[0097] (SM) The fifth drive circuit 370 is controlled to be turned on or off in response to a control signal IPD1_On. In the on state, the fifth drive circuit 370 supplies a drive current ILED5 to turn on the fifth light source 210.

[0098] The derating control in the vehicular lamp 200A of Fig. 5 will be described. The microcontroller 390 receives the outputs of the thermistors 220, 222, and 224 (i.e., temperature information) and the voltage V DDH Derating control is performed based on the detected value indicating the above.

[0099] For example, for the second light source 204 for DRL / POS, the input voltage V DDH Based on the three detection values ​​based on the output of the thermistor 222 and the output of the thermistor 224, the drive current I LED2 may be subjected to derating control.

[0100] Regarding the third light source 206 for low beam, the input voltage V DDH Based on the three detection values ​​based on the output of the thermistor 220 and the output of the thermistor 224, the drive current I LED3 may be subjected to derating control.

[0101] Regarding the first light source 202 for the turn signal lamp, the input voltage V DDH Based on the two detection values ​​based on the output of the thermistor 224, the drive current I LED1 may be subjected to derating control.

[0102] Regarding the fourth light source 208 for high beam, the input voltage V DDH Based on the two detection values ​​based on the output of the thermistor 224, the drive current I LED4 may be subjected to derating control.

[0103] In this case, the non-volatile memory 308 stores the voltage V DDH2. A parameter group that specifies the derating for thermistor 220, a parameter group that specifies the derating for thermistor 222, and a parameter group that specifies the derating for thermistor 224 may be written.

[0104] The present invention has been described above based on an embodiment. This embodiment is merely an example, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component and each processing step, and that such modifications are also within the scope of the present invention. Such modifications will be described below.

[0105] In the vehicular lamp 200A of FIG. 5, the power supply circuit 304 may be omitted, and the DC / DC converters 342, 332, and 352 may be configured as boost converters.

[0106] In the vehicular lamp 200A of FIG. 5, the second light source 204 and the third light source 206 are driven by a common converter, but this is not limiting, and the second light source 204 and the third light source 206 may be driven by separate converters.

[0107] The parameters that define the derating characteristics are not limited to those described above, and may be defined so as to uniquely determine the derating characteristics. The shape of the derating characteristics is not limited to those described above, and may be expressed using a quadratic function or other functions.

[0108] In the embodiment, the components of the lamp control module 300 are modularized by being housed in the same housing, but this is not limited thereto, and the components may be divided into a plurality of housings, packages, modules, or boards.

[0109] The present invention has been described using specific terms based on the embodiments, but the embodiments merely illustrate the principles and applications of the present invention, and many modifications and changes in arrangement are permitted to the embodiments without departing from the spirit of the present invention as defined in the claims. [Explanation of symbols]

[0110] 100...lighting system, 102...power line, 104...Zika line, 106...vehicle bus, 110...vehicle, 200...vehicle lighting fixture, 202...first light source, 204...second light source, 206...third light source, 208...fourth light source, 210...fifth light source, 300...lamp control module, 302, 304...power supply circuit, 305...protection circuit, 306...A / D converter, 310...input interface circuit, 320...bus interface circuit, 330...first drive circuit, 340...second drive circuit, 350...third drive circuit, 360...fourth drive circuit, 370...fifth drive circuit, 390...microcontroller, 400...signal processing device.

Claims

1. A vehicle lamp, A first light source; 1st target current I ＲＥＦ１ a first drive circuit configured to supply a first drive current stabilized to the first light source; an A / D converter that receives at least one electrical signal indicating a state of the vehicle lamp and generates at least one detection value corresponding to the at least one electrical signal; (i) the base current value I of the first drive current ＢＡＳＥ１ (ii) a non-volatile memory that stores at least one parameter group that defines a derating characteristic of the first light source based on each of the at least one detection value; The base current value I ＢＡＳＥ１ and the first target current I ＲＥＦ１ A signal processor for calculating and by changing values ​​of a group of parameters to be written to the non-volatile memory, the derating characteristic can be changed without changing the software program.

2. The at least one detection value is a temperature detection value T based on the output of a temperature sensor; A voltage detection value V based on the input voltage of the first drive circuit ＤＤ and, Including, The parameter group related to the temperature detection value T is the derating start temperature T Ｓ , derating end temperature T Ｅ , including the reduction rate α, The voltage detection value V ＤＤ The parameters for the derating start voltage V Ｓ , derating end voltage V Ｅ , including the reduction rate β, The signal processing device detects the temperature T and outputs a derated current I ＴＥＭＰ＿ＤＥＲ of, I ＴＥＭＰ＿ＤＥＲ =I ＢＡＳＥ１ (T<T Ｓ ) I ＴＥＭＰ＿ＤＥＲ =I ＢＡＳＥ１ {1-α(T-T Ｓ )} (T Ｓ <T<T Ｅ ) I ＴＥＭＰ＿ＤＥＲ =I ＢＡＳＥ１ {1-α(T Ｅ -T Ｓ )} (T Ｅ <T) Calculate based on The voltage detection value V ＤＤ The current amount I after derating ＶＯＬＴ＿ＤＥＲ of, I ＶＯＬＴ＿ＤＥＲ =I ＢＡＳＥ１ (V ＤＤ <V Ｓ ) I ＶＯＬＴ＿ＤＥＲ =I ＢＡＳＥ１ {1-β(V ＤＤ -V Ｓ )} (V Ｓ <V ＤＤ <V Ｅ ) I ＶＯＬＴ＿ＤＥＲ =I ＢＡＳＥ１ {1-β(V Ｅ -V Ｓ )} (V Ｅ <V ＤＤ ) Based on this, the current I ＴＥＭＰ＿ＤＥＲ and I ＶＯＬＴ＿ＤＥＲ The smaller of the two is the first target current I ＲＥＦ１ 2. The vehicle lamp according to claim 1, wherein:

3. The parameter group related to the temperature detection value T is an abnormality determination temperature T ＭＡＸ Further comprising: The signal processing device is T ＭＡＸ In the range of T, I ＴＥＭＰ＿ＤＥＲ 3. The vehicular lamp according to claim 2, wherein:

4. The at least one detection value is A temperature detection value T based on the output of the first temperature sensor １ and, A temperature detection value T based on the output of the second temperature sensor ２ and, Including, The detected temperature value T １ The parameter group for the derating start temperature T Ｓ１ , derating end temperature T Ｅ１ , reduction rate α １ Including, The detected temperature value T ２ The parameter group for the derating start temperature T Ｓ２ , derating end temperature T Ｅ２ , reduction rate α ２ Including, The signal processing device detects the temperature T １ The current amount I after derating ＴＥＭＰ＿ＤＥＲ１ of, I ＴＥＭＰ＿ＤＥＲ１ =I ＢＡＳＥ１ (T １ <T Ｓ１ ) I ＴＥＭＰ＿ＤＥＲ１ =I ＢＡＳＥ１ {1-α １ (T １ -T Ｓ１ )} (T Ｓ１ <T １ <T Ｅ１ ) I ＴＥＭＰ＿ＤＥＲ１ =I ＢＡＳＥ１ {1-α １ (T Ｅ１ -T Ｓ１ )} (T Ｅ１ <T １ ) Calculate based on The detected temperature value T ２ The current amount I after derating ＴＥＭＰ＿ＤＥＲ２ of, I ＴＥＭＰ＿ＤＥＲ２ =I ＢＡＳＥ１ (T ２ <T Ｓ２ ) I ＴＥＭＰ＿ＤＥＲ２ =I ＢＡＳＥ１ {1-α ２ (T ２ -T Ｓ２ )} (T Ｓ２ <T ２ <T Ｅ２ ) I ＴＥＭＰ＿ＤＥＲ２ =I ＢＡＳＥ１ {1-α ２ (T Ｅ２ -T Ｓ２ )} (T Ｅ２ <T ２ ) Based on this, the current I ＴＥＭＰ＿ＤＥＲ１ and I ＴＥＭＰ＿ＤＥＲ２ The smaller of the two is the first target current I ＲＥＦ１ 2. The vehicle lamp according to claim 1, wherein:

5. The at least one detection value is A temperature detection value T based on the output of the first temperature sensor １ and, A temperature detection value T based on the output of the second temperature sensor ２ and, A voltage detection value V based on the input voltage of the first drive circuit ＤＤ and, Including, The detected temperature value T １ The parameter group for the derating start temperature T Ｓ１ , derating end temperature T Ｅ１ , reduction rate α １ Including, The detected temperature value T ２ The parameter group for the derating start temperature T Ｓ２ , derating end temperature T Ｅ２ , reduction rate α ２ Including, The voltage detection value V ＤＤ The parameters for the derating start voltage V Ｓ , derating end voltage V Ｅ , including the reduction rate β, The signal processing device detects the temperature T １ The current amount I after derating ＴＥＭＰ＿ＤＥＲ１ of, I ＴＥＭＰ＿ＤＥＲ１ =I ＢＡＳＥ１ (T １ <T Ｓ１ ) I ＴＥＭＰ＿ＤＥＲ１ =I ＢＡＳＥ１ {1-α １ (T １ -T Ｓ１ )} (T Ｓ１ <T １ <T Ｅ１ ) I ＴＥＭＰ＿ＤＥＲ１ =I ＢＡＳＥ１ {1-α １ (T Ｅ１ -T Ｓ１ )} (T Ｅ１ <T １ ) Calculate based on The detected temperature value T ２ The current amount I after derating ＴＥＭＰ＿ＤＥＲ２ of, I ＴＥＭＰ＿ＤＥＲ２ =I ＢＡＳＥ１ (T ２ <T Ｓ２ ) I ＴＥＭＰ＿ＤＥＲ２ =I ＢＡＳＥ１ {1-α ２ (T ２ -T Ｓ２ )} (T Ｓ２ <T ２ <T Ｅ２ ) I ＴＥＭＰ＿ＤＥＲ２ =I ＢＡＳＥ１ {1-α ２ (T Ｅ２ -T Ｓ２ )} (T Ｅ２ <T ２ ) Calculate based on The voltage detection value V ＤＤ The current amount I after derating ＶＯＬＴ＿ＤＥＲ of, I ＶＯＬＴ＿ＤＥＲ =I ＢＡＳＥ１ (V ＤＤ <V Ｓ ) I ＶＯＬＴ＿ＤＥＲ =I ＢＡＳＥ１ {1-β(V ＤＤ -V Ｓ )} (V Ｓ <V ＤＤ <V Ｅ ) I ＶＯＬＴ＿ＤＥＲ =I ＢＡＳＥ１ {1-β(V Ｅ -V Ｓ )} (V Ｅ <V ＤＤ ) Based on this, the current I ＴＥＭＰ＿ＤＥＲ１ , I ＴＥＭＰ＿ＤＥＲ２ , I ＶＯＬＴ＿ＤＥＲ The smallest one of the first target current I ＲＥＦ１ 2. The vehicle lamp according to claim 1, wherein:

6. The detected temperature value T １ The parameter group related to the abnormality determination temperature T ＭＡＸ１ Further comprising: The detected temperature value T ２ The parameter group related to the abnormality determination temperature T ＭＡＸ２ Further comprising: The signal processing device is T ＭＡＸ１ <T １ In the range of I ＴＥＭＰ＿ＤＥＲ１ = 0, T ＭＡＸ２ <T ２ In the range of I ＴＥＭＰ＿ＤＥＲ２ 6. The vehicular lamp according to claim 4, wherein:

7. the first drive circuit, the A / D converter, the non-volatile memory, and the signal processing device are configured as a single module; The first temperature sensor is provided inside the module, 7. The vehicular lamp according to claim 5, wherein the second temperature sensor is provided outside the module.

8. A second light source; 2nd target current I ＲＥＦ２ a second drive circuit configured to supply a second drive current stabilized to the second light source; Further equipped with The non-volatile memory stores a base current value I ＢＡＳＥ２ Further storing The signal processing device detects the base current value I ＢＡＳＥ２ and the second target current I ＲＥＦ２ 8. The vehicle lamp according to claim 1, wherein the following is calculated:

9. A lamp control module for use in a vehicle lamp having a first light source, 1st target current I ＲＥＦ１ a first drive circuit configured to supply a first drive current stabilized to the first light source; an A / D converter that receives at least one electrical signal indicating a state of the vehicle lamp and generates at least one detection value corresponding to the at least one electrical signal; (i) the base current value I of the first drive current ＢＡＳＥ１ (ii) a non-volatile memory that stores at least one parameter group that defines a derating characteristic of the first light source based on each of the at least one detection value; The base current value I ＢＡＳＥ１ and the first target current I ＲＥＦ１ A signal processor for calculating and wherein the derating characteristic can be changed by changing the values ​​of a group of parameters to be written to the non-volatile memory, without changing the software program.

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