Control device, vehicle lamp, and program

Abstract

The objective of the present invention is to suppress a variation in control when using a plurality of control circuits to control a light source having a plurality of light emitting elements. This control device is communicably connected to a control instruction device that transmits control instructions for a plurality of light sources, and includes a plurality of control circuits that control each of the plurality of light sources in accordance with the control instructions. The control instruction device repeatedly transmits, to each of the control circuits, with a first period, a common control instruction for instructing the lighting patterns of the plurality of light sources. Each of the plurality of control circuits receives the control instruction, controls the light source in accordance with the lighting pattern specified in the control instruction, on the basis of a timing generated by a timer incorporated into each control circuit, and synchronizes each timer repeatedly on the basis of the timing at which the control instruction is received, with a second period that is longer than a unit control period, which is the period required to control a control unit of the lighting pattern, and that is n times (n is a natural number) the length of the first period.

Description

Control device, vehicle lighting fixture, and program

[0001] The present invention relates to a control device, a vehicle lamp, and a program.

[0002] This application claims priority based on Japanese Patent Application Nos. 2023-188668 and 2023-188669, both of which were filed on November 2, 2023, the entire disclosures of which are incorporated herein by reference.

[0003] Patent Document 1 describes a vehicle headlamp (hereinafter referred to as "lamp") equipped with a lamp ECU (Electronic Control Unit) that controls a communication lamp to display the battery charge level while the vehicle is stopped. The communication lamp includes an elongated light guide that extends continuously along a straight or curved line, and a plurality of light-emitting elements (hereinafter referred to as "light sources") arranged at intervals along the length of the light guide. The lamp ECU controls the light output of each light-emitting element so that the light-emitting range of the light guide changes depending on the battery charge level.

[0004] International Publication No. WO2019 / 159828A1

[0005] When trying to control a light source having a large number of light-emitting elements to function as a communication lamp, such as the lighting fixture described in Patent Document 1, it is necessary to use multiple control circuits (integrated circuits (ICs)) to control the light source.

[0006] These multiple control circuits individually control the lighting of the light sources based on the timing generated by their respective built-in timers. However, if the timing discrepancies between the control circuits accumulate due to errors (tolerances) in the timers of the individual control circuits, this can lead to noticeable variations in the control of the light sources as a whole.

[0007] The present invention has been made in consideration of this background, and aims to provide a control device, a vehicle lighting fixture, and a program that are capable of suppressing control variations when controlling a light source having multiple light-emitting elements using multiple control circuits.

[0008] One aspect of the present invention for achieving the above-mentioned object is a control device that is communicatively connected to a control instruction device that transmits control instructions for a plurality of light sources, and includes a plurality of control circuits that control each of the plurality of light sources in response to the control instructions, wherein the control instruction device repeatedly transmits a common control instruction instructing a lighting pattern for the plurality of light sources to each of the control circuits in a first period, and each of the plurality of control circuits receives the control instruction and controls the light source according to the lighting pattern specified in the control instruction based on timing generated by a timer built into each of the control circuits, and repeatedly synchronizes each of the timers in a second period that is longer than a unit control period, which is the period required to control a control unit of the lighting pattern, and is n times (n is a natural number) the first period, based on the timing at which the control instruction is received.

[0009] Another aspect of the present invention for achieving the above-mentioned object is a control device including a plurality of control circuits communicably connected to a control instruction device that transmits control instructions for a plurality of light sources, and that controls each of the plurality of light sources in accordance with the control instructions, wherein the control instruction device repeatedly transmits a common control instruction instructing a lighting pattern for the plurality of light sources to each of the control circuits at a predetermined cycle, and each of the plurality of control circuits receives the control instruction, and a first control circuit of the plurality of control circuits controls the light source in accordance with the lighting pattern specified in the received control instruction, based on timing generated by a built-in timer, and communicates with a second control circuit of the plurality of control circuits and transmits a control signal to the second control circuit instructing the light source to be turned on or off in accordance with the lighting pattern, and the second control circuit receives the control signal and controls the turning on or off of the light source that is the respective control target based on the received control signal.

[0010] Other problems and solutions disclosed in the present application will be made clear in the detailed description and drawings.

[0011] According to the present invention, it is possible to suppress variations in control when a light source having a plurality of light-emitting elements is controlled using a plurality of control circuits.

[0012] FIG. 1 is a diagram showing an example of a lamp provided in a vehicle; FIG. 2 is a diagram showing the main circuit configuration of a lamp of a first embodiment; FIG. 3 is a diagram explaining the configuration of one unit of a light source; FIG. 4 is a diagram showing an example of a lighting pattern; FIG. 5 is a diagram explaining synchronization deviation; FIG. 6 is a diagram explaining a mechanism for suppressing synchronization deviation; FIG. 7 is a diagram explaining a case where a control circuit misses an opportunity for synchronization; FIG. 8 is a diagram explaining the operation of a control circuit when a lighting pattern is changed; FIG. 9 is a diagram showing the main circuit configuration of a lamp of a second embodiment; FIG. 10 is a diagram explaining a first method; and FIG. 11 is a diagram explaining a second method.

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0014] In the following description, the same or similar components will be denoted by the same reference numerals, and redundant description will be omitted.

[0015] In addition, in the following description, when it is necessary to distinguish between similar configurations, the configuration may be indicated by adding a subscript (number, letter, etc.) after the symbol that collectively refers to the configuration (for example, the symbol "11" may be written as "11A," "11B," or "11C").

[0016] FIG. 1 shows a side view of the exterior of an electric vehicle (EV) (hereinafter referred to as "vehicle C") according to one embodiment. In this figure, the vertical direction of the paper is the up-down direction (vertical direction). The horizontal direction of the paper is the fore-and-aft direction of vehicle C (the forward direction of vehicle C is "forward" and the backward direction is "rear"). The direction perpendicular to both the fore-and-aft direction and the up-and-down direction is the left-and-right direction (the front side of the paper is "left" and the back side is "right").

[0017] A lamp 1 (vehicle lamp) is provided on the front left side of vehicle C to inform people of the state (charge control state, SOC (State Of Charge), etc.; hereinafter referred to as the "charge state") of a battery 2 (storage battery) mounted on vehicle C. Lamp 1 has a display (indicator) (hereinafter referred to as the "charge lamp 20") that informs people of the charge state of battery 2. Note that a lamp 1 is also provided on the front right side of vehicle C, but since the basic configuration is the same as that of lamp 1 on the front left side, the following description will focus on lamp 1 on the front left side.

[0018] 2 shows the main circuit configuration of the lighting fixture 1. As shown in the figure, the lighting fixture 1 includes a charging lamp 20 and a lighting circuit 10 (control device) that controls the lighting of the charging lamp 20.

[0019] 1 and 2, the charging lamp 20 includes a plurality of light source groups (light source group 21, light source group 22, light source group 23). These are arranged adjacent to each other in the fore-and-aft direction of the vehicle C in the order of light source group 21, light source group 22, light source group 23.

[0020] As shown in FIG. 2, light source group 21 includes four light sources 21A to 21D arranged in order in the front-to-rear direction, light source group 22 includes five light sources 22A to 22E arranged in order in the front-to-rear direction, and light source group 23 includes five light sources 23A to 23E arranged in order in the front-to-rear direction, so that charging lamp 20 includes a total of 14 light sources.

[0021] Each of the light sources (light sources 21A to 21D, light sources 22A to 22E, and light sources 23A to 23E) includes two chips 25 (light-emitting chips). Each chip 25 includes a light-emitting element that emits red light, a light-emitting element that emits green light, and a light-emitting element that emits blue light. The illustrated charging lamp 20 includes a total of 28 chips 25 (= 14 chips × 2).

[0022] 3 shows the configuration of one unit of light sources (light sources 21A to 21D, light sources 22A to 22E, light sources 23A to 23E). As shown in the figure, one light source includes two chips 25. On chip 25, a light-emitting element Dr that emits red light, a light-emitting element Dg that emits green light, and a light-emitting element Db that emits blue light are arranged side by side. Furthermore, the light-emitting elements of the same color on the two chips 25 are connected in series.

[0023] 2, the lighting circuit 10 is realized, for example, as a substrate module or package on which various circuits (including integrated circuits) for controlling each light source are formed. The lighting circuit 10 operates using power supplied from a power supply line L1. The lighting circuit 10 includes control circuits 11A to 11C, switch circuits 13A to 13C, and current generation circuits 15A to 15C.

[0024] The anodes of the light-emitting elements on the power supply side of each of the four light sources 21A to 21D of the light source group 21 are connected to the power supply line L1 via a switch circuit 13A. Each of the four light sources 21A to 21D is controlled by a control circuit 11A.

[0025] The ground-side cathode of each of the light-emitting elements Dr of the four light sources 21A to 21D is connected to a terminal Tr of the control circuit 11A via a current generating circuit 15A. The ground-side cathode of each of the light-emitting elements Dg of the four light sources 21A to 21D is connected to a terminal Tg of the control circuit 11A via a current generating circuit 15A. The ground-side cathode of each of the light-emitting elements Db of the four light sources 21A to 21D is connected to a terminal Tb of the control circuit 11A via a current generating circuit 15A.

[0026] The anodes of the light-emitting elements on the power supply side of each of the five light sources 22A to 22E of the light source group 22 are connected to the power supply line L1 via a switch circuit 13B. The five light sources 22A to 22E are each controlled by a control circuit 11B.

[0027] The ground-side cathode of each of the light-emitting elements Dr of the five light sources 22A to 22E is connected to a terminal Tr of the control circuit 11B via a current generating circuit 15B. The ground-side cathode of each of the light-emitting elements Dg of the five light sources 22A to 22E is connected to a terminal Tg of the control circuit 11B via a current generating circuit 15B. The ground-side cathode of each of the light-emitting elements Db of the five light sources 22A to 22E is connected to a terminal Tb of the control circuit 11B via a current generating circuit 15B.

[0028] The anodes of the light-emitting elements on the power supply side of each of the five light sources 23A to 23E of the light source group 23 are connected to the power supply line L1 via a switch circuit 13C. The five light sources 23A to 23E are each controlled by a control circuit 11C.

[0029] The ground-side cathode of each of the light-emitting elements Dr of the five light sources 23A to 23E is connected to a terminal Tr of the control circuit 11C via a current generating circuit 15C. The ground-side cathode of each of the light-emitting elements Dg of the five light sources 23A to 23E is connected to a terminal Tg of the control circuit 11C via a current generating circuit 15C. The ground-side cathode of each of the light-emitting elements Db of the five light sources 23A to 23E is connected to a terminal Tb of the control circuit 11C via a current generating circuit 15C.

[0030] The lighting circuit 10 controls each light source in accordance with a lighting pattern instruction signal Sa (control instruction) input from an ECU 100 (Electronic Control Unit) (control instruction device) installed in the vehicle C (transmitted from the ECU 100 to the lighting circuit 10).

[0031] The power supply line L1 of the lighting circuit 10 is a wiring that supplies a power supply voltage Vbat to the internal circuits and each light source of the lighting circuit 10. The power supply voltage Vbat of the battery 2 is applied to the power supply line L1. When the power supply voltage Vbat is applied to the power supply line L1, an input voltage Vin is input to the lighting circuit 10.

[0032] The lighting circuit 10 communicates with the ECU 100 via a Local Interconnect Network (LIN) (hereinafter also referred to as "LIN communication") and lights up each light source in a lighting pattern specified by an instruction signal Sa sent from the ECU 100. In this example, LIN is used as the communication method between the lighting circuit 10 and the ECU 100, but the above communication method may be another method such as a Controller Area Network (CAN).

[0033] The control circuits 11A to 11C control the lighting of each light source (light sources 21A to 21D, light sources 22A to 22E, light sources 23A to 23E) of the light source groups 21 to 23. Each of the control circuits 11A to 11C is configured using an integrated circuit (IC) that integrates circuits such as a microcomputer (arithmetic unit, information processing unit), an RGB driver, a LIN transceiver, and a timer. The timer generates timing (timing signal) for controlling the lighting of the light sources of the light source groups 21 to 23.

[0034] Each of the control circuits 11A to 11C has input / output terminals (input terminal (LIN_IN), output terminal (LIN_OUT)) for the instruction signal Sa (LIN signal) sent from the ECU 100, GPIO terminals (GPIO1 to GPIO5) (general-purpose input / output terminals (GPIO)) for outputting pulse signals S1 to S5 (the control circuit 11A outputs pulse signals S1 to S4) to the corresponding switch circuits, and terminals Tr, Tg, and Tb for controlling the current flowing through the light source.

[0035] Based on an instruction signal Sa sent from the ECU 100, each of the control circuits 11A to 11C controls the current flowing to the light source via the terminals Tr, Tg, and Tb.

[0036] The control circuit 11A receives the instruction signal Sa sent from the ECU 100 at its input terminal (LIN_IN), and outputs the received LIN signal to its output terminal (LIN_OUT) (through (a signal input to the terminal is output to another IC via the terminal)). The control circuit 11B receives the LIN signal output from the output terminal (LIN_OUT) of the control circuit 11A at its input terminal (LIN_IN), and outputs the received LIN signal to its output terminal (LIN_OUT) (through). The control circuit 11C receives the LIN signal sent from the control circuit 11B at its input terminal (LIN_IN). Each of the control circuits 11A to 11C receives the instruction signal Sa sent from the ECU 100 in the manner described above.

[0037] In this embodiment, the control circuits 11A to 11C sequentially cooperate to receive the instruction signal Sa, but the configuration may also be such that the ECU 100 inputs the instruction signal Sa to the LIN signal input terminal (LIN_IN) of each of the control circuits 11A to 11C, so that each of the control circuits 11A to 11C receives the instruction signal Sa from the ECU 100.

[0038] The control circuits 11A to 11C are all sink-type (current-sinking) ICs that sink current through terminals Tr, Tg, and Tb, causing current to flow through the light-emitting elements of the light sources connected to the power supply line L1, causing the light-emitting elements to emit light.

[0039] Here, the control circuits 11A to 11C are provided with terminals Tr, Tg, and Tb, each corresponding to a light-emitting element Dr, Dg, and Db of each color. Therefore, if one light source (light-emitting element Dr, Dg, and Db) were controlled by one control circuit, the number of control circuits would increase, leading to increased costs and a larger circuit size. Therefore, in this embodiment, switch circuits 13A to 13C are provided so that one control circuit controls multiple light sources in a time-division manner, thereby reducing costs and circuit size.

[0040] In this embodiment, the lighting circuit 10 is provided with current generating circuits 15A to 15C, so that a current larger than the capacity of the control circuits 11A to 11C can be passed through the light source (light emitting element).

[0041] <Lighting Pattern> The ECU 100 inputs an instruction signal Sa to the lighting circuit 10, instructing the control circuits 11A to 11C to control the lighting pattern according to the state of charge of the battery 2. Each of the control circuits 11A to 11C of the lighting circuit 10 lights up the charging lamp 20 in the lighting pattern specified by the instruction signal Sa input from the ECU 100.

[0042] FIG. 4 shows an example of a lighting pattern that the ECU 100 specifies in the instruction signal Sa.

[0043] As shown in the figure, the ECU 100 uses the instruction signal Sa to specify a lighting pattern of "white / sequential" (a lighting pattern in which a predetermined length of white light flows from the front to the back of the charging lamp 20) to indicate that the charging state is "preparing to charge," for example.

[0044] In addition, the ECU 100 specifies, by means of the instruction signal Sa, a lighting pattern of "blue / sequential" (a lighting pattern in which a predetermined length of blue display flows from the front to the back of the charging lamp 20) to indicate that the charging state is "energized," for example.

[0045] In addition, the ECU 100 specifies the lighting pattern as "blue / lit" (a lighting pattern in which the entire light source is lit in blue) using the instruction signal Sa to indicate that the charging state is "charging completed (fully charged, specified capacity reached)," for example.

[0046] In addition, the ECU 100 specifies, by the instruction signal Sa, for example, a lighting pattern of "red / flashing" (a lighting pattern in which the entire light source flashes red) to indicate that the charging state is "charging stopped."

[0047] Furthermore, the ECU 100 uses the instruction signal Sa to specify, for example, a lighting pattern of "white / lit" (a lighting pattern in which the entire light source is lit in white) to indicate that the charging state is "other."

[0048] <Timer Synchronization Deviation> Each of the control circuits 11A to 11C independently controls the lighting of its assigned light source based on the timing (timing signal) generated by its own built-in timer. Therefore, if the error (tolerance) of the timer of each of the control circuits 11A to 11C accumulates over time and the deviation of the timer of each of the control circuits 11A to 11C (hereinafter referred to as "synchronization deviation") increases, there is a possibility that a variation in control that is noticeable to a person will occur, and there is a possibility that unified control of all the light sources provided in the charging lamp 20 will not be possible.

[0049] For example, consider a case where each of the control circuits 11A to 11C synchronizes its timer and starts control according to the input lighting pattern based on the time when the control circuit 11A to 11C starts receiving the instruction signal Sa specifying control according to a predetermined lighting pattern from the ECU 100 (the time when the control circuit 11A to 11C receives the instruction signal Sa specifying a new lighting pattern). Note that the timers are synchronized by, for example, resetting the timers (initializing the starting point of the timer count).

[0050] FIG. 5 is a timing chart for explaining the synchronization deviation of the control circuits 11A to 11C.

[0051] The "lighting pattern" in the figure indicates a period during which the ECU 100 selects a predetermined lighting pattern to instruct the lighting circuit 10. In this example, the ECU 100 selects "red / flashing" as the lighting pattern to instruct the lighting circuit 10 during a period during which the "lighting pattern" is "High (ON)."

[0052] "LIN_IN" in the figure indicates the timing at which the ECU 100 inputs (transmits) the instruction signal Sa to the lighting circuit 10. In this example, the ECU 100 inputs the instruction signal Sa to the lighting circuit 10 at a cycle of 100 ms.

[0053] "Lighting control" in the figure indicates the specific control content that each control circuit 11A to 11C performs on the light source that it is responsible for controlling, with respect to the lighting pattern specified in the instruction signal Sa. Note that in the figure, each control circuit 11A to 11C is represented as IC1 to IC3, respectively.

[0054] As shown in the figure, each control circuit 11A to 11C receives an instruction signal Sa specifying a new lighting pattern of "red lighting / flashing" input from the ECU 100 at time t1, and begins controlling the light source according to the lighting pattern specified in the received instruction signal Sa.

[0055] In this example, the control of the lighting pattern "red / flashing" is assumed to be a control to turn the light source red for 200 ms and then turn it off for 200 ms. Each of the control circuits 11A to 11C repeatedly performs the above control on the light source that it is responsible for controlling at a cycle of 400 ms (= 200 ms + 200 ms).

[0056] In addition, in this example, each control circuit 11A to 11C synchronizes its timer at the timing when it receives the above-mentioned instruction signal Sa from ECU 100 at time t1, and thereafter repeats the above-mentioned control at the above-mentioned period based on the timing (timing signal) generated by the timer built into each control circuit.

[0057] As described above, after the timers of the control circuits 11A to 11C are synchronized at time t1, they do not synchronize their timers until an instruction signal Sa specifying a new lighting pattern different from the current lighting pattern is input from (received from) the ECU 100 (hereinafter referred to as the "duration period"). Therefore, if the duration period is long, errors in the timers of the control circuits 11A to 11C accumulate, resulting in variations in control noticeable to humans, making it impossible to achieve unified control of the entire light source. Note that, for example, in the example of FIG. 4, the duration period is likely to be long when the charging state is "powered on," "charging completed," or "charging stopped."

[0058] Therefore, in the first embodiment, the mechanism described below is used to suppress synchronization errors between the timers of each control circuit 11A to 11C, thereby suppressing variations in the control of the light source by each control circuit 11A to 11C even when the duration is long.

[0059] [First Embodiment] <Suppression of Synchronization Loss> In this embodiment, in order to suppress synchronization loss between the timers of the control circuits 11A to 11C, the control circuits 11A to 11C synchronize their timers with respect to the timing at which the instruction signal Sa is received in a second cycle that is longer than the period (hereinafter referred to as the "unit control period") required for one control of the lighting pattern (hereinafter referred to as the "unit control") and that is n times (n is a natural number) the first cycle, which is the cycle in which the ECU 100 inputs (transmits) the instruction signal Sa to the lighting circuit 10. Note that, for example, when the lighting pattern is "red / blinking" in FIG. 4, the unit control includes one control of "turning on red" and one control of "turning off."

[0060] Fig. 6 is a timing chart for explaining the above mechanism. Note that the "lighting pattern", "LIN_IN", and "lighting control" in Fig. 6 are the same as those in Fig. 5, and therefore their explanations will be omitted.

[0061] As shown in the figure, in this example, the ECU 100 repeatedly inputs an instruction signal Sa to the lighting circuit 10 at a period of 100 ms (first period).

[0062] Furthermore, when the ECU 100 starts inputting an instruction signal Sa to the lighting circuit 10 at time t1 instructing the lighting circuit 10 to perform control using a lighting pattern, each of the control circuits 11A to 11C starts controlling the light source using the lighting pattern "red / flashing" specified by the received instruction signal Sa, and performs unit control (unit control period is 370 ms (= 200 ms + 170 ms)) in which the light source that each control circuit is responsible for controlling is turned on in red for 200 ms and then turned off for 170 ms, and this unit control is repeated in a cycle of 400 ms (second cycle (= 100 ms × 4)).

[0063] Then, each control circuit 11A to 11C repeatedly synchronizes its respective timers based on the timing at which the instruction signal Sa is received (using that timing as the starting point for timing) each time it receives an instruction signal Sa from the ECU 100 in the second cycle (at each of the times t2, t3, t4, etc. in the same figure).

[0064] According to the above mechanism, each of the control circuits 11A to 11C repeatedly synchronizes its timer every time the second period arrives (every 400 ms in this example), which prevents the accumulation of errors in the timers of the control circuits 11A to 11C during the duration. This prevents the occurrence of control variations that are noticeable to humans, and allows consistent control to be maintained across all light sources.

[0065] In the above mechanism, the unit control period is made shorter than the second cycle by a predetermined time (30 ms (= 400 ms - 370 ms) in the above example, hereinafter referred to as the "buffer period"), but this is to prevent the unit control period from becoming longer than the second cycle due to a timer error (the control period (200 ms) to turn off the light source extends into the next second cycle), causing the control circuit 11 to miss the opportunity to synchronize (reset) the timer.

[0066] 7 shows an example of a situation in which the control circuit 11 misses an opportunity for synchronization due to the lack of a buffer period. In this example, each of the control circuits 11A to 11C repeats the control of the lighting pattern "red / flashing" specified by the instruction signal Sa input from the ECU 100 at time t1 (control of lighting the light source red for 200 ms, and then turning it off for 200 ms) in a cycle of 400 ms.

[0067] As shown in the figure, if the control period (200 ms) for turning off the light source of control circuit 11B overlaps with the subsequent second cycle due to a timer synchronization error, control circuit 11B will miss the opportunity to synchronize the timer (the opportunity to synchronize at the start of the subsequent second cycle), and as a result, the timing at which the synchronized red light will start will be delayed by 100 ms compared to the other control circuits 11A and 11C.

[0068] On the other hand, if a buffer period is provided as shown in Fig. 6, the error can be absorbed in the period from the end of the unit control period to the arrival of the subsequent second period, thereby preventing the opportunity for synchronization with the subsequent second period from being missed.

[0069] It should be noted that the length of the buffer period (30 ms (= 200 ms - 170 ms) in the example of FIG. 6) is preferably set based on the range of error, etc., to be short enough not to affect the display of the lighting pattern, and long enough to prevent the above situation from occurring.

[0070] <When switching (changing) lighting pattern> In the mechanism shown in FIG. 6 , when the lighting circuit 10 is controlling the light source with the lighting pattern specified by the instruction signal Sa (hereinafter referred to as the “first lighting pattern”), if the lighting circuit 10 receives from the ECU 100 an instruction signal Sa specifying a lighting pattern (hereinafter referred to as the “second lighting pattern”) different from the current lighting pattern (when switching (changing) the lighting pattern), each of the control circuits 11A to 11C resynchronizes based on the timing at which the instruction signal Sa was received, and then starts controlling the light source with the second lighting pattern.

[0071] 8 is a timing chart illustrating the operation of each of the control circuits 11A to 11C when switching the lighting pattern. This diagram illustrates a case where each of the control circuits 11A to 11C controls the light source with the first lighting pattern of "red / flashing" and receives an instruction signal Sa specifying the second lighting pattern of "blue / sequential" from the ECU 100.

[0072] Each of the control circuits 11A to 11C starts controlling the light source using the first lighting pattern "red / flashing" specified by the received instruction signal Sa, based on the timing at time t1 when the lighting circuit 10 receives the instruction signal Sa from the ECU 100. Furthermore, each of the control circuits 11A to 11C repeatedly synchronizes the timer with a second cycle (T2, T3) starting from time t1.

[0073] As shown in the figure, at time t1', 800 ms after time t1, when lighting circuit 10 receives instruction signal Sa specifying the second lighting pattern "blue / sequential" from ECU 100, each control circuit 11A to 11C resynchronizes its timer at time t2 and starts controlling the light source using the second lighting pattern "blue / sequential." After that, each control circuit 11A to 11C repeatedly synchronizes its timer every time the second cycle starting from time t2 arrives.

[0074] In this way, when each of the control circuits 11A to 11C receives from the ECU 100 an instruction signal Sa that specifies a second lighting pattern different from the first lighting pattern currently being controlled for the light source, it resynchronizes based on the timing at which the instruction signal Sa was received, and switches to control that synchronizes the timers with a second cycle starting from that timing. Therefore, even when the lighting pattern is switched, it is possible to continue to prevent accumulation of errors in the timers of the control circuits 11A to 11C.

[0075] As described above, according to this embodiment, each control circuit 11A to 11C repeatedly synchronizes its respective timer in the second cycle, thereby preventing the accumulation of errors in the timers of each control circuit 11A to 11C, preventing the occurrence of control variations that are noticeable to humans, and maintaining consistent control across the entire light source.

[0076] Furthermore, in this embodiment, a buffer period is provided that is long enough to prevent the time difference between the unit control period and the second cycle from becoming longer than the second cycle due to an error in the timers of each of the control circuits 11A to 11C, thereby preventing the unit control period from becoming longer than the second cycle due to an error in the timers, which would result in missing the timing of synchronization with the subsequent second cycle.

[0077] Furthermore, in this embodiment, when each control circuit 11A to 11C receives from ECU 100 an instruction signal Sa that specifies a lighting pattern different from the lighting pattern that is currently being controlled, the control switches to a control that synchronizes the timer with a second period based on the timing at which the instruction signal Sa was received. Therefore, when the lighting pattern instructed by the instruction signal Sa changes, the control can immediately switch to a control that synchronizes the timer with a second period based on the timing at which the instruction signal Sa was received.

[0078] The above mechanism can be applied to a control system in which the ECU 100 (control instruction device) and the control circuits 11A to 11C are communicably connected via a LIN (Local Interconnect Network).

[0079] Furthermore, the above mechanism can be applied to a control system in which, for example, the ECU 100 (control instruction device) and each of the control circuits 11A to 11C are configured by an integrated circuit having an arithmetic circuit configured using a CPU (Central Processing Unit), an MPU (Micro Processing Unit), an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), etc.

[0080] The arithmetic circuit implements the functions of the ECU 100 (control instruction device) and the control circuits 11A to 11C by reading and executing a program stored in a memory device of the integrated circuit (or a memory device attached to the integrated circuit). The memory device is configured using, for example, a RAM (Random Access Memory), a ROM (Read Only Memory), or an NVRAM (Non Volatile Random Access Memory).

[0081] [Second Embodiment] In the second embodiment, the mechanisms (first method and second method) described below are used to suppress variations in the control of the light source by each of the control circuits 11A to 11C described in conjunction with FIG. 5.

[0082] Fig. 9 shows the main circuit configuration of the lamp 1 of the second embodiment. The circuit configuration of the lamp 1 of the second embodiment is basically the same as the circuit configuration of the lamp 1 of the first embodiment shown in Fig. 2, but in the lamp 1 of the second embodiment, each of the control circuits 11A to 11C has an additional GPIO terminal (GPIO6) in addition to the above-mentioned GPIO terminals (GPIO1 to GPIO5).

[0083] <First Method> In the first method, the timing generated by the timer of the control circuit 11A (first control circuit) is shared among the control circuits 11A to 11C via the GPIO terminal (GPIO6) of each of the control circuits 11A to 11C, thereby suppressing variation in the control of the light source by each of the control circuits 11A to 11C.

[0084] Specifically, first, the control circuit 11A controls the turning on or off of the light sources 21A to 21D that it is responsible for in accordance with the lighting pattern specified in the instruction signal Sa received from the ECU 100, based on the timing generated by its own timer, and inputs a control signal instructing the turning on or off of the light source to the GPIO terminals (GPIO6) of the control circuit 11B and the control circuit 11C via the GPIO terminal (GPIO6).

[0085] On the other hand, the control circuits 11B and 11C synchronize their respective timers using a control signal input to the GPIO terminal (GPIO6), and control the turning on or off of the light sources 22A to 22E and 23A to 23E that they are responsible for based on the timing generated by the timers built into each of them.

[0086] In addition, each control circuit 11A to 11C controls lighting patterns other than turning on or off, such as brightness and light color, in accordance with the lighting pattern specified in the instruction signal Sa received from ECU 100 via LIN communication.

[0087] 10 is a timing chart illustrating the first method. The "lighting pattern," "LIN_IN," and "lighting control" in the figure are the same as those in FIG. 5, and therefore will not be described here. Also, in the figure, the control circuits 11A to 11C are denoted as IC1 to IC3, respectively.

[0088] The "lighting state" in the figure represents the lighting state of the light source (for the control circuit 11A (IC1 in the figure), the lighting state of the light source group 21 (light sources 21A to 21D); for the control circuit 11B (IC2 in the figure), the lighting state of the light source group 22 (light sources 22A to 22E); and for the control circuit 11C (IC3 in the figure), the lighting state of the light source group 23 (light sources 23A to 23E)).

[0089] "GPIO output" in the figure is a control signal output from the GPIO terminal (GPIO6) by the control circuit 11A, which is used by the control circuits 11B and 11C to synchronize their respective timers. The control signal is "High (ON)" when the light source is turned on, and is "Low (OFF)" when the light source is turned off.

[0090] "GPIO input" in the figure is the control signal input from the control circuit 11A to the GPIO terminal (GPIO6) of each of the control circuits 11B and 11C.

[0091] As shown in the figure, the ECU 100 repeatedly inputs an instruction signal Sa to each of the control circuits 11A to 11C at a cycle of 100 ms via LIN communication.

[0092] When the ECU 100 starts inputting an instruction signal Sa to the lighting circuit 10 instructing the lighting circuit 10 to control the light source using the lighting pattern "red / flashing", the control circuit 11A starts controlling the light source using the lighting pattern "red / flashing" specified by the received instruction signal Sa.

[0093] In addition, the control circuit 11A controls the light sources 21A to 21D that it controls to light up in red for 200 ms and then turn them off for 200 ms in accordance with the lighting pattern "red / blinking" specified by the input instruction signal Sa, and repeats this control at a cycle of 400 ms.

[0094] In addition, the control circuit 11A starts outputting a control signal (in this example, a signal that is "High (on)" during the red lighting period (200 ms) and "Low (off)" during the off period (200 ms)) synchronized with the control of the light sources 21A to 21D that it is responsible for controlling from the GPIO terminal (GPIO6).

[0095] On the other hand, the control circuits 11B and 11C synchronize their respective timers based on control signals input to their respective GPIO terminals (GPIO6), and control the turning on and off of the light sources that they are responsible for.

[0096] As mentioned above, the control circuits 11B and 11C control lighting patterns other than turning on or off, such as brightness and light color, in accordance with the lighting patterns specified in the instruction signal Sa received from the ECU 100 via LIN communication.

[0097] As described above, in the first method, the timing generated by the timer of the control circuit 11A is shared among the control circuits 11A to 11C via the GPIO terminal (GPIO6) of each of the control circuits 11A to 11C, thereby enabling synchronized control of the control circuits 11A to 11C as a whole, and enabling consistent control to be maintained across the entire light source.

[0098] Furthermore, since communication between general-purpose input / output ports (GPIO terminals) is faster than LIN communication, the control of turning on or off the light source by each control circuit 11A to 11C can be synchronized with higher precision than the second method described below.

[0099] <Second Method> In the second method, the timing generated by the timer of the control circuit 11A (first control circuit) is shared through LIN communication (hereinafter referred to as "local LIN communication") in which the control circuit 11A (first control circuit) is the master and the control circuit 11B (second control circuit) and the control circuit 11C (second control circuit) are slaves, thereby suppressing variation in the control of the light source by each of the control circuits 11A to 11C.

[0100] Specifically, first, the control circuit 11A controls the turning on or off of the light sources 21A to 21D that it is responsible for in accordance with the lighting pattern specified in the instruction signal Sa received from the ECU 100, based on the timing generated by its own timer, and inputs a control signal instructing the turning on or off of the light sources to the control circuits 11B and 11C via local LIN communication.

[0101] On the other hand, the control circuits 11B and 11C control the turning on and off of the light sources 22A to 22E and light sources 23A to 23B, respectively, in accordance with control signals input via local LIN communication.

[0102] In addition, each control circuit 11A to 11C controls lighting patterns other than turning on or off, such as brightness and light color, in accordance with the lighting pattern specified in the instruction signal Sa received from ECU 100 via LIN communication.

[0103] Fig. 11 is a timing chart illustrating the second method. Note that the "lighting pattern," "LIN_IN," and "lighting control" in Fig. 11 are the same as those in Fig. 5, and the "lighting state" is the same as that in Fig. 10, so their explanation will be omitted. Also, in Fig. 11, the control circuits 11A to 11C are denoted as IC1 to IC3, respectively.

[0104] In the figure, "LIN_OUT (local)" is a control signal that the control circuit 11A outputs from the output terminal (LIN_OUT) and inputs to the input terminals (LIN_IN) of the control circuits 11B and 11C. In this example, the control circuit 11A inputs control signals (signals that specify the timing of turning the light source on or off) to the control circuits 11B and 11C at a cycle of 100 ms. The control signal output from "LIN_OUT (local)" is slightly delayed from the timing at which the instruction signal Sa is input to "LIN_IN" of the control circuit 11A. This delay occurs, for example, due to internal processing of the control circuit 11A.

[0105] The "light source drive instruction" in the figure is the content of the control signal (light source drive instruction) output from "LIN_OUT (local)." In this example, the content of the control signal is "High (on)" when the light source is turned on, and is "Low (off)" when the light source is turned off.

[0106] As shown in the same figure, the control circuit 11B (IC2) and the control circuit 11C (IC3) control the turning on or off of the light source that they are responsible for in response to the control signal input to their respective input terminals (LIN_IN) via local LIN communication.

[0107] As described above, in the second method, a control signal is sent from control circuit 11A to control circuit 11B and control circuit 11C via local LIN communication, and control circuit 11B and control circuit 11C control the turning on or off of the light source that they are responsible for in accordance with the received control signal, thereby enabling synchronized control of each of control circuits 11A to 11C as a whole, and maintaining uniform control of all light sources.

[0108] Furthermore, the second method does not consume a general-purpose input / output port (GPIO terminal) for communication as in the first method, so it can be implemented even when there are no free general-purpose input / output ports in the control circuits 11A to 11C, and the general-purpose input / output ports can be effectively used for other purposes.

[0109] As described above, according to the second embodiment, the control circuit 11A acts as the main control circuit, and the secondary control circuits 11B and 11C control the turning on and off of the light source, thereby suppressing variations in the control of the light source by each of the control circuits 11A to 11C, and maintaining consistent control of the light source as a whole.

[0110] Furthermore, as in the first method, by transmitting a control signal that conveys timing generated by the timer of the control circuit 11A to the control circuits 11B and 11C, and sharing the control signal among the control circuits 11A to 11C via the GPIO terminals (GPIO6) of each of the control circuits 11A to 11C, synchronized control of the control circuits 11A to 11C as a whole is possible, and consistent control of the entire light source can be maintained. Furthermore, because communication between general-purpose input / output ports (GPIO terminals) is faster than LIN communication, synchronization of the control of the light source on and off by each of the control circuits 11A to 11C can be achieved with higher precision than in the second method.

[0111] In addition, as in the second method, by transmitting a control signal from the control circuit 11A to the control circuit 11B and the control circuit 11C via local LIN communication, and the control circuit 11B and the control circuit 11C controlling the on / off of the light source that they are responsible for in response to the received control signal, synchronized control of the control circuits 11A to 11C as a whole is possible, and uniform control of all the light sources can be maintained. Furthermore, the second method does not consume a general-purpose input / output port (GPIO terminal) as in the first method, and therefore can be implemented even if there are no available general-purpose input / output ports in the control circuits 11A to 11C.

[0112] Furthermore, in both the first and second methods, when it comes to controlling lighting patterns other than turning on or off, the control circuits 11B and 11C perform control in accordance with the lighting patterns specified in the control instructions they each receive, so the control signal sent from the control circuit 11A (first control circuit) to the control circuit 11B (second control circuit) and the control circuit 11C (second control circuit) can be a simple signal (on / off signal) that conveys only the timing of turning on or off the light, which can be easily controlled by a general-purpose input / output port (GPIO terminal) or local LIN communication.

[0113] The above mechanism can be applied to a control system in which the ECU 100 (control instruction device) and the control circuits 11A to 11C are communicably connected via a LIN (Local Interconnect Network).

[0114] Furthermore, the above mechanism can be applied to a control system in which, for example, the ECU 100 (control instruction device) and each of the control circuits 11A to 11C are configured by an integrated circuit having an arithmetic circuit configured using a CPU (Central Processing Unit), an MPU (Micro Processing Unit), an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), etc.

[0115] The arithmetic circuit implements the functions of the ECU 100 (control instruction device) and the control circuits 11A to 11C by reading and executing a program stored in a memory device of the integrated circuit (or a memory device attached to the integrated circuit). The memory device is configured using, for example, a RAM (Random Access Memory), a ROM (Read Only Memory), or an NVRAM (Non Volatile Random Access Memory).

[0116] <Summary> Although the embodiments of the present invention (first embodiment and second embodiment) have been described in detail above, the present invention is not limited to the above-described embodiments and includes various modifications. Furthermore, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, some of the configurations of the above-described embodiments can be added to, deleted from, or replaced with other configurations.

[0117] C Vehicle Sa Indicator signal L1 Power supply line 1 Lamp 2 Battery 10 Lighting circuit 11A to 11C Control circuit 13A to 13C Switch circuit 15A to 15C Current generating circuit 20 Charging lamp 21 to 23 Light source group 21A to 21D Light source 22A to 22E Light source 23A to 23E Light source 100 ECU

Claims

1. A control device including a plurality of control circuits communicatively connected to a control instruction device that transmits control instructions for a plurality of light sources, and that controls each of the plurality of light sources in response to the control instructions, wherein the control instruction device repeatedly transmits a common control instruction instructing a lighting pattern of the plurality of light sources to each of the control circuits in a first period, and each of the plurality of control circuits receives the control instruction and controls the light sources according to the lighting pattern specified in the control instruction based on a timing generated by a timer built into each of the control circuits, and repeatedly synchronizes each of the timers based on the timing of receiving the control instruction in a second period that is longer than a unit control period, which is a period required to control a control unit of the lighting pattern, and is n times (n is a natural number) the first period.

2. A control device as claimed in claim 1, wherein the time difference between said unit control period and said second cycle is set to a length such that an error in the timers of each of said control circuits will not cause said unit control period to become longer than said second cycle.

3. A control device as described in claim 1, wherein, when each of the control circuits in the plurality of control circuits receives from the control instruction device a control instruction specifying a lighting pattern different from the lighting pattern currently being controlled for the light source, the control circuit switches to control that synchronizes the timer with the second period based on the timing at which the control instruction was received.

4. A control device according to claim 1, wherein the control circuit is communicably connected to the control instruction device via a LIN (Local Interconnect Network).

5. A control device according to claim 1, wherein each of said control instruction device and said control circuit is an integrated circuit having an arithmetic circuit.

6. A vehicular lamp comprising: a plurality of light sources constituting a display that displays the charging state of a secondary battery mounted in a vehicle; and a plurality of control circuits communicably connected to a control instruction device that transmits control instructions for the plurality of light sources and that controls each of the plurality of light sources in response to the control instructions, wherein the control instruction device repeatedly transmits a common control instruction instructing a lighting pattern of the plurality of light sources to each of the control circuits in a first period, and each of the plurality of control circuits receives the control instruction and controls the light sources according to the lighting pattern specified in the control instruction based on a timing generated by a timer built into each of the control circuits, and repeatedly synchronizes each of the timers based on the timing of receiving the control instruction in a second period that is longer than a unit control period, which is a period required to control a control unit of the lighting pattern, and is n times (n is a natural number) the first period.

7. A control device including a plurality of control circuits communicably connected to a control instruction device that transmits control instructions for a plurality of light sources and that controls each of the plurality of light sources in response to the control instructions, wherein the control instruction device repeatedly transmits a common control instruction instructing a lighting pattern of the plurality of light sources to each of the control circuits in a first period, wherein each of the plurality of control circuits receives the control instruction and controls the light sources in the lighting pattern specified in the control instruction based on a timing generated by a timer built into each of the control circuits, and wherein the control device is configured to repeatedly synchronize each of the timers based on the timing at which the control instruction was received in a second period that is longer than a unit control period that is a control period for the lighting pattern and has a length n times (n is a natural number) the first period, A program for realizing a function of repeatedly synchronizing each of the timers based on the timing of receiving the control instruction in a second period that is longer than a unit control period, which is the period required to control a control unit of the lighting pattern, and that is n times (n is a natural number) as long as the first period.

8. A control device including a plurality of control circuits communicably connected to a control instruction device that transmits control instructions for a plurality of light sources, and controlling each of the plurality of light sources in response to the control instructions, wherein the control instruction device repeatedly transmits a common control instruction instructing a lighting pattern of the plurality of light sources to each of the control circuits at a predetermined period, and each of the plurality of control circuits receives the control instruction, and a first control circuit among the plurality of control circuits controls the light source in accordance with the lighting pattern specified in the received control instruction based on timing generated by a built-in timer, communicates with a second control circuit among the plurality of control circuits, and transmits a control signal to the second control circuit instructing the second control circuit to turn on or off the light source in accordance with the lighting pattern, and the second control circuit receives the control signal, and controls the turning on or off of the light sources that are the respective control targets based on the received control signal.

9. A control device according to claim 8, wherein each of said control circuits has a general-purpose input / output port, and said control signal is transmitted from said general-purpose input / output port of said first control circuit to said general-purpose input / output port of said second control circuit.

10. A control device according to claim 8, wherein the control circuit has a LIN (Local Interconnect Network) communication port, and the control signal is transmitted from the LIN communication port of the first control circuit to the communication port of the second control circuit.

11. A control device as claimed in claim 8, wherein each of the second control circuits controls a lighting pattern other than turning on or off in accordance with a lighting pattern specified in the control instruction received by each of the second control circuits.

12. A control device according to claim 8, wherein the control instruction device and the control circuit are integrated circuits each having an arithmetic circuit.

13. A vehicular lamp comprising: a plurality of light sources constituting an indicator that displays the charging state of a secondary battery mounted in a vehicle; and a plurality of control circuits communicatively connected to a control instruction device that transmits control instructions for the plurality of light sources, and controlling each of the plurality of light sources in accordance with the control instructions, wherein the control instruction device repeatedly transmits a common control instruction instructing a lighting pattern of the plurality of light sources to each of the control circuits at a predetermined cycle, and each of the plurality of control circuits receives the control instruction, and a first control circuit of the plurality of control circuits controls the light sources in accordance with the lighting pattern specified in the received control instruction, based on timing generated by a built-in timer, communicates with a second control circuit of the plurality of control circuits, and transmits a control signal to the second control circuit instructing the second control circuit to turn on or off the light sources in accordance with the lighting pattern, and the second control circuit receives the control signal and controls the turning on or off of the light sources that are the respective control targets in accordance with the received control signal.

14. A control device including a plurality of control circuits communicably connected to a control instruction device that transmits control instructions for a plurality of light sources and that controls each of the plurality of light sources in response to the control instructions, wherein the control instruction device repeatedly transmits a common control instruction instructing a lighting pattern of the plurality of light sources to each of the control circuits at a predetermined cycle, wherein each of the plurality of control circuits receives the control instruction, and a first control circuit among the plurality of control circuits controls the light source in accordance with the lighting pattern specified in the received control instruction based on a timing generated by a built-in timer, communicates with a second control circuit among the plurality of control circuits, and transmits a control signal to the second control circuit instructing the second control circuit to turn on or off the light source in accordance with the lighting pattern, and the second control circuit receives the control signal and controls the turning on or off of the light sources that are each subject to control based on the received control signal, wherein the first control circuit has a function of controlling the light source in accordance with the lighting pattern specified in the received control instruction based on a timing generated by a built-in timer, a function of communicating with the second control circuit among the plurality of control circuits, and a program for realizing a function of transmitting a control signal to the second control circuit to instruct the second control circuit to turn on or off the light source in accordance with the lighting pattern.

15. A control device including a plurality of control circuits communicably connected to a control instruction device that transmits control instructions for a plurality of light sources and that controls each of the plurality of light sources in response to the control instructions, wherein the control instruction device repeatedly transmits a common control instruction instructing a lighting pattern of the plurality of light sources to each of the control circuits at a predetermined cycle, wherein the plurality of control circuits each receive the control instruction, and a first control circuit among the plurality of control circuits controls the light source in accordance with the lighting pattern specified in the received control instruction based on timing generated by a built-in timer, communicates with a second control circuit among the plurality of control circuits, and transmits a control signal to the second control circuit instructing the second control circuit to turn on or off the light source in accordance with the lighting pattern, and the second control circuit receives the control signal and controls the lighting or off of the light sources that are each subject to control based on the received control signal. A program for realizing a function in the second control circuit to receive the control signal and control the lighting or off of the light sources that are each subject to control in accordance with the received control signal.