Lighting circuit and vehicle direction indicator

Abstract

During a first period in which the first light source (24) is lit and the second light source (25) is not lit, and a second period in which the first light source (24) and the second light source (25) are lit, the linear regulator (40) supplies a first drive current (I1) to the first light source (24), and stops supplying the first drive current (I1) during a third period in which the first light source (24) and the second light source (25) are extinguished. The switching regulator (41) supplies a second drive current (I2) to the second light source (25) during the second period, and stops supplying the second drive current (I2) during the third period.

Description

Technical Field

[0001] The present disclosure relates to a lighting circuit and a vehicle direction indicator lamp. Background Art

[0002] In a vehicle direction indicator lamp (hereinafter referred to as a "turn signal lamp"), there is a technique using a so-called sequential method in which a plurality of light sources are sequentially lit (for example, refer to Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-119449 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] However, in the case of a turn signal lamp using the sequential method, there is a timing at which the lighting circuit lights only a part of the plurality of light sources. At such a timing, since the power consumed in the turn signal lamp is small, the current supplied from the vehicle-side power source to the turn signal lamp (hereinafter referred to as "input current") also becomes small.

[0008] Therefore, in the case where a detection device that detects a light source disconnection when the input current is less than a specified value is provided in a vehicle, the detection device may erroneously detect a light source disconnection at a timing when only a part of the light sources are lit, for example.

[0009] There is a need to provide a lighting circuit that can prevent misdetection of a light source disconnection in a turn signal lamp.

[0010] Means for Solving the Problems

[0011] To meet the above requirements, according to one aspect of the present disclosure, there is provided a lighting circuit applicable to a vehicle direction indicator lamp, the lighting circuit causing a first light source including at least one light-emitting element and a second light source including at least one light-emitting element to blink, and including:

[0012] A first regulator that supplies a specified first drive current to the first light source based on power from a power line during a first period in which the first light source is lit and the second light source is not lit, and during a second period in which the first light source and the second light source are lit, and stops supplying the first drive current to the first light source during a third period in which the first light source and the second light source are extinguished;

[0013] A second regulator, having a higher power conversion efficiency than the first regulator, supplies a prescribed second drive current to the second light source based on power from the power supply line during the second period, and stops supplying the second drive current to the second light source during the third period; and

[0014] A control circuit repeatedly controls the second regulator in a prescribed cycle including the first period to the third period.

[0015] To meet the above requirements, according to one aspect of the present disclosure, a vehicle turn signal is provided, which includes:

[0016] A first light source including at least one light-emitting element;

[0017] A second light source including at least one light-emitting element; and

[0018] A lighting circuit that causes the first light source and the second light source to blink

[0019] The lighting circuit includes:

[0020] A first regulator that supplies a prescribed first drive current to the first light source based on power from the power supply line during a first period in which the first light source is lit and the second light source is not lit, and during a second period in which the first light source and the second light source are lit, and stops supplying the first drive current to the first light source during a third period in which the first light source and the second light source are extinguished;

[0021] A second regulator, having a higher power conversion efficiency than the first regulator, supplies a prescribed second drive current to the second light source based on power from the power supply line during the second period, and stops supplying the second drive current to the second light source during the third period; and

[0022] A control circuit repeatedly controls the second regulator in a prescribed cycle including the first period to the third period. Description of the Drawings

[0023] Figure 1 is a diagram showing an example of a turn signal.

[0024] Figure 2 is a diagram showing an example of the allowable range of the input current to the turn signal.

[0025] Figure 3 is a diagram showing an example of an extinguishing circuit.

[0026] Figure 4 is a diagram for explaining the operation of the turn signal.

[0027] Figure 5 This is a diagram for explaining the input current when the turn signal operates.

[0028] Figure 6 This is a diagram showing an example of a turn signal.

[0029] Figure 7 This is a diagram for explaining the operation of the turn signal. Detailed implementation

[0030] Based on the description in this specification and the accompanying drawings, at least the following matters can be clarified.

[0031] <<Structure of the turn signal 10>>

[0032] Figure 1 This is a diagram showing an example of the structure of the turn signal 10 as an embodiment of the present invention. The turn signal 10 is a "vehicle direction indicator" that sequentially lights up a plurality of light sources based on the voltage Vbat of the vehicle battery 11.

[0033] The turn signal 10 is configured to include a switch 20, a microcomputer 21, a resistance circuit 22, a lighting circuit 23, a first light source 24, and a second light source 25.

[0034] The switch 20 is an element for applying a power source for operating the lighting circuit 23 to the power supply line L1 of the turn signal 10. The switch 20 uses, for example, a mechanical contact relay or a non-contact relay using semiconductor elements. One end of the switch 20 is applied with the voltage Vbat, and the other end is connected to the power supply line L1. Therefore, according to the instruction of the microcomputer 21, when the switch 20 is turned on, the voltage Vbat is applied to the power supply line L1. In addition, the power supply line L1 is a wiring for supplying power to the internal circuit of the lighting circuit 23 via a terminal A (described later).

[0035] The microcomputer 21 is a circuit for controlling the operation of the turn signal 10. For example, when the driver of the vehicle operates a direction indicator (not shown) to turn on the turn signal 10, the switch 20 is turned on and off at a specified "cycle Tx". In addition, the microcomputer 21 operates a sequential control circuit 44 (described later) provided in the lighting circuit 23 according to the operation result of the direction indicator, and the details will be described later.

[0036] The resistance circuit 22 is a circuit for adjusting the current value of the input current Iin supplied from the battery 11 to the turn signal 10, and is configured to include, for example, resistors R1 to R3 connected in series. In addition, here, the resistance circuit 22 is set to have three resistors R1 to R3 connected in series, but the connection method or the number of resistors is not limited to this, as long as it includes at least one resistor.

[0037] When the voltage Vbat is applied to the power supply line L1, the lighting circuit 23 sequentially lights the first light source 24 and the second light source 25 according to an instruction from the microcomputer 21. In addition, details of the lighting circuit 23 will be described later. The lighting circuit 23 is a module in which a plurality of circuits for lighting light-emitting elements (described later) and terminals A to G are mounted on a substrate.

[0038] The first light source 24 is a light source including two light-emitting elements, namely, the light-emitting element D1 that is lit first and the light-emitting element D2 that is lit after the light-emitting element D1. The light-emitting elements D1 and D2 are connected in series between the terminal D and the terminal F, and the cathode of the light-emitting element D1 and the anode of the light-emitting element D2 are connected to the terminal E.

[0039] The second light source 25 is a light source including 13 light-emitting elements D3 to D15 that are lit after the light-emitting element D2 of the first light source 24 is lit. In addition, the light-emitting elements D3 to D15 are connected in series between the terminal G and the terminal H.

[0040] In addition, in the present embodiment, in order to light the light-emitting elements D1 to D15, when a prescribed current (for example, 360 mA) is supplied to the light-emitting elements D1 to D15 respectively, the forward voltage of the light-emitting elements D1 to D15 becomes 3V, for example. Therefore, the voltage between the terminals D and F connecting the first light source 24 is 3V or 6V, and the voltage between the terminals G and H connecting the second light source 25 is 39V.

[0041] <<Allowable range of input current Iin>>

[0042] However, in a vehicle equipped with the turn signal lamp 10 of the present embodiment, a detection device (not shown) for detecting whether there is a break in the light-emitting element of the turn signal lamp 10 based on the input current Iin from the battery 11 is provided. For example, when the turn signal lamp 10 operates, the detection device detects that there is a break in the light-emitting element of the turn signal lamp 10 when the current value of the input current Iin is less than a "prescribed value Ix".

[0043] Therefore, when the turn signal lamp 10 operates in a normal state, the current value of the input current Iin needs to be greater than the "prescribed value Ix" so as not to be erroneously detected as a break in the light-emitting element. Here, the "normal state" means, for example, a state in which no break occurs in the light-emitting elements of the first light source 24 and the second light source 25 of the turn signal lamp 10. In addition, a "break in the light-emitting element" means a state in which the resistance value between the cathode and the anode of the light-emitting element is sufficiently larger than the normal resistance value, for example.

[0044] On the other hand, if the power consumption of the turn signal lamp 10 increases more than necessary, the input current Iin to the turn signal lamp 10 also increases, and thus the current from the battery 11 may sometimes exceed the rated current, for example.

[0045] Therefore, when the turn signal 10 operates, the input current Iin flowing from the battery 11 to the turn signal 10 needs to converge, for example, within Figure 2 the "allowable range X" shown.

[0046] Here, the "allowable range X" is, for example, the range between the "lower limit value" shown by the dashed line and the "upper limit value" shown by the dotted line when the voltage Vbat of the battery 11 varies, for example, between 9V and 16V. Additionally, the "lower limit value" is, for example, a value larger than the "specified value Ix" when it is detected whether there is a break in the light source of the turn signal 10. Further, the "upper limit value" is, for example, a value determined based on the capacity of the battery 11 or the rated current of the switch 20.

[0047] The lighting circuit 23 of the present embodiment converges the input current Iin within the "allowable range X" and causes the first light source 24 and the second light source 25 to blink.

[0048] <<<Structure of the lighting circuit 23>>>

[0049] As Figure 1 shown, the lighting circuit 23 is configured to include a linear regulator 40, a switching regulator 41, switches 42, 43, a sequence control circuit 44, open - circuit detection circuits 45, 46, an extinguishing circuit 47, and terminals A to H.

[0050] The linear regulator 40 is a linear - type constant - current circuit that generates a prescribed drive current I1 (for example, 360 mA) for driving the light - emitting elements D1, D2 of the first light source 24 as a load. Specifically, when the switch 20 is turned on and the voltage Vbat is applied to the power supply line L1, the linear regulator 40 generates a prescribed drive current I1 (for example, 360 mA) based on the power supplied from the power supply line L1. Additionally, when the signal S10 from the extinguishing circuit 47 becomes low level (hereinafter referred to as "L" level), the linear regulator 40 stops operating.

[0051] The switching regulator 41 is a switching - type constant - current circuit that generates a prescribed drive current I2 (for example, 360 mA) for driving the light - emitting elements D3 to D15 of the second light source 25 as a load. The switching regulator 41 is a constant - current circuit that generates the drive current I2 based on the power supplied from the power supply line L1 when a signal S1 of, for example, high level (hereinafter referred to as "H" level) is input from the sequence control circuit 44. Additionally, when the signal S11 from the extinguishing circuit 47 becomes "L" level, the switching regulator 41 stops operating.

[0052] In addition, herein, the so-called "state where the regulator stops operating" refers to a state where, for example, the regulator at least stops generating a drive current (e.g., a standby state). Further, the drive current I1 corresponds to the "first drive current", and the drive current I2 corresponds to the "second drive current".

[0053] However, in the present embodiment, as described above, the voltage Vbat of the battery 11 is, for example, 9 to 16 V, and the voltage between terminals D and F of the first light source 24 is 3 V or 6 V. Further, in the power transistor (not shown) that controls the drive current I1 included in the linear regulator 40, a relatively large amount of power corresponding to the difference between the voltage Vbat and the voltage between terminals D and F is consumed.

[0054] Therefore, in order to generate the drive current I1 of the first light source 24, a step-down switching regulator having a higher power conversion efficiency than the linear regulator may be used. However, in the case of using a step-down switching regulator, the current value of the input current Iin may sometimes be less than the above-mentioned "specified value Ix". Therefore, in the present embodiment, as the circuit for generating the drive current I1 of the first light source 24, the linear regulator 40 is used. Further, the linear regulator 40 corresponds to the "first regulator", and the switching regulator 41 corresponds to the "second regulator".

[0055] The switch 42 is an element (switching element) for making the terminal B to which the resistor circuit 22 is connected conduct to the ground and causing a current to flow through the resistor circuit 22. The switch 42 is turned on, for example, when both the signal S2 from the sequence control circuit 44 and the signal S12 from the extinguishing circuit 47 are at the "H" level, and is turned off when any one of the signals S2 and S12 is at a low level (hereinafter, referred to as the "L" level).

[0056] The switch 43 is an element for sequentially lighting the light-emitting elements D1 and D2 of the first light source 24, and is turned on when the signal S3 from the sequence control circuit 44 becomes the "H" level and is turned off when it becomes the "L" level. Here, the switch 43 is provided between the terminals E and F such that the switch 43 and the light-emitting element D2 are connected in parallel. Therefore, when the switch 43 is turned on, the drive current I1 is supplied only to the light-emitting element D1 among the light-emitting elements D1 and D2, and when the switch 43 is turned off, the drive current I1 is supplied to both the light-emitting elements D1 and D2.

[0057] The sequence control circuit 44 repeatedly controls the switching regulator 41, the switches 42 and 43 at a "specified period Tx" based on an instruction from the microcomputer 21 to sequentially light the light-emitting elements D1 to D15. Specifically, the sequence control circuit 44 outputs signals S1 to S3 for controlling the switching regulator 41, the switches 42 and 43, respectively. Further, details of the operation of the sequence control circuit 44 will be described later.

[0058] The disconnection detection circuit 45 detects whether there is a disconnection in the light-emitting elements D1 and D2 of the first light source 24 based on the output voltage of the linear regulator 40. Here, if any of the light-emitting elements D1 and D2 is disconnected, the resistance value between the anode and the cathode of the disconnected light-emitting element increases. In such a state, if a drive current I1 is supplied to the light-emitting elements D1 and D2, the output voltage of the linear regulator 40 rises significantly.

[0059] The disconnection detection circuit 45 of the present embodiment determines, for example, whether the output voltage of the linear regulator 40 is higher than a specified value V1. When the output voltage is higher than the specified value V1, it is detected that there is a disconnection in the first light source 24. And when the disconnection detection circuit 45 detects a disconnection, the level of the line L2 connecting the disconnection detection circuits 45 and 46 and the extinguishing circuit 47 is changed from the "H" level to the "L" level.

[0060] The disconnection detection circuit 46 detects whether there is a disconnection in the light-emitting elements D3 to D15 of the second light source 25 based on the output voltage of the switching regulator 41. Similar to the disconnection detection circuit 45, when the output voltage of the switching regulator 41 is higher than a specified value V2, it is detected that there is a disconnection in the second light source 25, and the level of the line L2 is changed from the "H" level to the "L" level. In addition, the disconnection detection circuits 45 and 46 respectively correspond to the "first determination circuit" and the "second determination circuit", and the specified values V1 and V2 respectively correspond to the "first specified value" and the "second specified value".

[0061] When the extinguishing circuit 47 detects a disconnection in either of the disconnection detection circuits 45 and 46, in order to turn off the first light source 24 and the second light source 25, the operations of the linear regulator 40 and the switching regulator 41 are stopped. In addition, the extinguishing circuit 47 disconnects the switch 42 based on the disconnection detection result of either of the disconnection detection circuits 45 and 46 to prevent useless power from being consumed in the resistance circuit 22. The extinguishing circuit 47 is configured to include a capacitor 60, inverters 61 and 62, and Schottky barrier diodes 63 to 65.

[0062] The capacitor 60 is an element that is charged when the switch 20 is turned on and a voltage Vbat is applied to the power supply line L1, and holds the charge for operating the inverters 61 and 62. In addition, the capacitor 60 is charged, for example, via a diode (not shown) connected to the power supply line L1. Here, if the forward voltage of the diode for charging the capacitor 60 is set as the voltage Vf, in the present embodiment, the voltage Vdd of the capacitor 60 becomes a value smaller than the voltage Vbat by the voltage Vf.

[0063] The inverter 61 is a circuit that inverts the logic level of line L2 and outputs it, and includes a PNP transistor 70, a diode 71, and a resistor 72 connected in series. For example, when the level of line L2 is at the "H" level, the PNP transistor 70 is cut off, so the node N1 to which the diode 71 and the resistor 72 are connected becomes the "L" level. On the other hand, when the level of line L2 is at the "L" level, the PNP transistor 70 is turned on, so the node N1 becomes the "H" level.

[0064] The inverter 62 is a circuit that inverts the logic level of node N1 and outputs it, and includes an NMOS transistor 80, and resistors 81 and 82 connected in series. Here, for example, when the level of node N1 is at the "H" level, since the NMOS transistor 80 is turned on, the level of the node N2 to which the NMOS transistor 80 and the resistor 81 are connected becomes the "L" level. In addition, when the level of node N1 is at the "L" level, the NMOS transistor 80 is cut off, so the level of the node N2 becomes the "H" level.

[0065] In the present embodiment, the node N1, which is the output of the inverter 61, is connected to the gate electrode of the NMOS transistor 80, which is the input of the inverter 62. In addition, the node between the resistors 81 and 82 of the inverter 62 is connected to the base electrode of the PNP transistor 70, which is the input of the inverter 61, via the connection line L2. Therefore, the extinguishing circuit 47 operates as a holding circuit for holding the logic level of the line L2.

[0066] The Schottky barrier diode 63 generates an "L" level signal S10 for stopping the operation of the linear regulator 40 at the anode when there is a disconnection detection and the extinguishing circuit 47 holds an "L" level signal.

[0067] The Schottky barrier diode 64 generates an "L" level signal S11 for stopping the operation of the switching regulator 41 at the anode when there is a disconnection detection and the extinguishing circuit 47 holds an "L" level signal.

[0068] The Schottky barrier diode 65 generates an "L" level signal S12 for disconnecting the switch 42 at the anode when there is a disconnection detection and the extinguishing circuit 47 holds an "L" level signal.

[0069] <<<Operation of the lighting circuit 23>>>

[0070] Figure 4This is a diagram for explaining the operation of the lighting circuit 23. Here, for example, when a direction indicator (not shown) for flashing the turn signal 10 is operated, the microcomputer 21 of the present embodiment repeatedly turns on and off the switch 20 at a specified "cycle Tx (e.g., 700 ms)". Additionally, it is assumed that the periods during which the switch 20 is turned on and off in the cycle Tx are each half of the cycle Tx (350 ms).

[0071] Furthermore, during the period when the switch 20 is turned on, the sequence control circuit 44 controls various circuits and components to increase the number of illuminated light-emitting elements, such as "1", "2", "15". Hereinafter, in the present embodiment, the period when "1" light-emitting element D1 is illuminated is set as "period Ta (e.g., 65 ms)", and the period when "2" light-emitting elements D1 and D2 are illuminated is set as "period Tb (e.g., 65 ms)".

[0072] In addition, the period when the first light source 24 is illuminated is set as "first period T1 (e.g., 130 ms)", the period when the first light source 24 is illuminated is set as "second period T2 (e.g., 220 ms)", and the period when the first light source 24 and the second light source 25 are extinguished is set as "third period T3 (e.g., 350 ms)". Here, since none of the light-emitting elements D1 to D15 are open-circuited, the extinguishing circuit 47 maintains a signal of "H" level.

[0073] First, at time t0, if a direction indicator (not shown) for flashing the turn signal 10 is operated, the microcomputer 21 turns on the switch 20. As a result, the voltage Vbat of the battery 11 is applied to the power supply line L1, so the linear regulator 40 starts and generates a drive current I1.

[0074] Also, at time t0, based on an instruction from the microcomputer 21, the sequence control circuit 44 outputs a signal S3 of "H" level, so the switch 43 turns on. As a result, the drive current I1 is supplied only to the light-emitting element D1 among the light-emitting elements D1 and D2 of the first light source 24, and "1" light-emitting element D1 is illuminated.

[0075] Furthermore, at time t0, based on an instruction from the microcomputer 21, the sequence control circuit 44 changes the signal S2 to "H" level, so the switch 42 turns on. As a result, in addition to the linear regulator 40, an input current Iin also flows through the resistor circuit 22. Therefore, as Figure 5 shown, in the present embodiment, it is possible to reliably make the "current value Ia" of the input current Iin at this timing greater than the "lower limit value".

[0076] In addition, here, at time t0, switch 42 is turned on, and a part of the input current Iin flows through the resistor circuit 22, but it is not limited thereto. Specifically, when the power consumption of the linear regulator 40 is large enough, the turn signal lamp 10 does not need to be provided with the resistor circuit 22 and the switch 42.

[0077] At time t1 when only "period Ta (e.g., 65 ms)" has elapsed since time t0, the sequential control circuit 44 changes the signal S3 to the "L" level and turns off the switch 43. As a result, the drive current I1 is supplied to the light emitting elements D1 and D2 of the first light source 24, so the "two" light emitting elements D1 and D2 are lit. In addition, in the present embodiment, the amount of power consumed by the linear regulator 40 during "period Ta" is the same as the amount of power consumed by the light emitting element D2 during "period Tb". Therefore, as Figure 5 shown, the current value of the input current Iin during "the first period T1" becomes, for example, "current value Ia".

[0078] At time t2 when only "period Tb (e.g., 65 ms)" has elapsed since time t1, the sequential control circuit 44 changes the signal S1 to the "H" level and changes the signal S2 to the "L" level. As a result, the switching regulator 41 is started, and the drive current I2 is supplied to the light emitting elements D3 to D15, so a total of "fifteen" light emitting elements D1 to D15 are lit. Therefore, since the power consumption in the second light source 25 increases, the input current Iin increases sharply.

[0079] However, in the present embodiment, since the switch 42 is turned off at this timing, no current flows through the resistor circuit 22. Therefore, as Figure 5 shown, although the current value of the input current Iin increases from "current value Ia" to, for example, "current value Ib", it is possible to prevent "current value Ib" from exceeding the "upper limit value".

[0080] In addition, at time t3 when only "the second period T2 (e.g., 220 ms)" has elapsed since the time when the first light source 24 and the second light source 25 are turned off, the microcomputer 21 turns off the switch 20. As a result, since the power supply to the turn signal lamp 10 is stopped, the operations of the linear regulator 40 and the switching regulator 41 also stop. Therefore, the supply of the drive current I1 to the light emitting elements D1 and D2 and the supply of the drive current I2 to the light emitting elements D3 to D15 are also stopped, so the first light source 24 and the second light source 25 are turned off.

[0081] Then, at time t4 when only "the third period T3 (e.g., 350 ms)" has elapsed since the time t3 when the first light source 24 and the second light source 25 are turned off, the microcomputer 21 turns on the switch 20 again. Therefore, in the "cycle Tx" after time t4, the operations from time t0 to time t4 are repeated.

[0082] In addition, it is described here that none of the light-emitting elements D1 to D15 are open-circuited. However, for example, in the case where any one of the light-emitting elements D1 to D15 is open-circuited, the extinguishing circuit 47 stops the operations of the linear regulator 40 and the switching regulator 41. Therefore, in this case, even if the voltage Vbat is applied to the power supply line L1, the lighting circuit 23 does not light the first light source 24 and the second light source 25. In addition, at this time, since the extinguishing circuit 47 disconnects the switch 42, the power consumed by the turn signal lamp 10 is substantially zero.

[0083] <<<Other Embodiments>>>

[0084] For example, the first light source 24 includes two light-emitting elements D1 and D2, but is not limited thereto. For example, the first light source 24 may also include three light-emitting elements.

[0085] In addition, it is assumed that the first light source 24 and the second light source 25 each include a plurality of light-emitting portions. Here, a "light-emitting portion" is composed of at least one light-emitting element. For example, when the first light source 24 includes three light-emitting elements, the light source is composed of a light-emitting portion including one light-emitting element and a light-emitting portion including two light-emitting elements. And, for example, when one light-emitting element is connected between terminals D and E and two light-emitting elements are connected between terminals E and F, the lighting circuit 23 sequentially lights "one", "three", and "sixteen" light-emitting elements.

[0086] In addition, in the present embodiment, it is assumed that all "thirteen" light-emitting elements D3 to D15 of the second light source 25 are lit in the "second period T2", but is not limited thereto. Specifically, the lighting circuit 23 may also, in the same manner as the first light source 24, in the "second period T2", after lighting the first light-emitting portion of the second light source 25 including "three" light-emitting elements, light the second light-emitting portion including the remaining "ten" light-emitting elements. Such sequential lighting of the second light source 25 in the "second period T2" can be achieved, for example, by providing a switch (not shown) connected in parallel with the second light-emitting portion of the second light source 25 and disconnecting it at a specified timing in the "second period T2" by the sequential control circuit 44.

[0087] <<<Structure of the Turn Signal Lamp 15>>>

[0088] Figure 6 is a diagram showing an example of the structure of the turn signal lamp 15 as an embodiment of the present invention. The turn signal lamp 15 is configured to include a switch 20, a microcomputer 21, a resistor circuit 22, a first light source 24, a second light source 25, and a lighting circuit 30. In addition, in Figure 6 , the same reference numerals are given to the blocks having the same structure as Figure 1 the same.

[0089] The lighting circuit 30 and Figure 1 the lighting circuit 23 are the same in that they are circuits that cause the first light source 24 and the second light source 25 to be lit in sequence. It includes a linear regulator 40, a switching regulator 41, switches 42, 43, SW1 to SW13, a sequence control circuit 50, disconnection detection circuits 45, 46 (not shown), an extinguishing circuit 47, and terminals A to H. Here, if the lighting circuit 30 is compared with Figure 1 the lighting circuit 23, the structures are the same except for the switches SW1 to SW13 and the sequence control circuit 50. Therefore, the following will be described centering on the switches SW1 to SW13 and the sequence control circuit 50. In addition, the lighting circuit 30 includes Figure 1 the disconnection detection circuits 45, 46 shown, but these are omitted here for convenience.

[0090] The switches SW1 to SW13 are switches connected in series to cause the light-emitting elements D3 to D15 of the second light source 25 to be lit in sequence. One end of the switch SW1 is connected to the cathode of the light-emitting element D3, and the other end of the switch SW1 is connected to the anode of the light-emitting element D3. Therefore, the switch SW1 is connected in parallel with the light-emitting element D3. In addition, the switches SW2 to SW13 are each connected in parallel with the light-emitting elements D4 to D15 in the same manner as the switch SW1. In addition, the switches SW1 to SW13 and the light-emitting elements D3 to D15 are connected via terminals (not shown).

[0091] The sequence control circuit 50, like the sequence control circuit 44, repeatedly controls the switching regulator 41, the switches 42, 43, SW1 to S13 according to an instruction from the microcomputer 21 at a "predetermined period Tx" to cause the light-emitting elements D1 to D15 to be lit in sequence. Specifically, the sequence control circuit 44 outputs signals S1 to S4 for controlling the switching regulator 41, the switches 42, 43, and the switches SW1 to SW13 respectively. Here, since the signals S1 to S3 output by the sequence control circuit 50 have been described, the signal S4 for controlling the switches SW1 to SW13 will be described.

[0092] The sequence control circuit 50 outputs the signal S4 in the "second period T2" of the "period Tx" and disconnects the switches one by one in sequence starting from the switch SW1 on the ground side among the 13 switches SW1 to SW13. Specifically, the sequence control circuit 50, at the moment t10 when the "second period T2" shown in Figure 7 starts, only disconnects the switch SW1 among the switches SW1 to SW13 and turns on the other switches SW2 to SW13. As a result, the drive current I2 from the switching regulator 41 only flows through the light-emitting element D3 among the light-emitting elements D3 to D15 of the second light source 25, so the three light-emitting elements D1 to D3 are lit.

[0093] In addition, when the time reaches t11, the sequence control circuit 50 turns off switches SW1 and SW2 among switches SW1 to SW13, and turns on the other switches SW3 to SW13. As a result, the drive current I2 flows through the light-emitting elements D3 and D4, so that the four light-emitting elements D1 to D4 are lit. After that, based on the signal S4, the sequence control circuit 50 turns off the switches on the ground side one by one among the switches SW3 to SW13 at regular time intervals. As a result, in the "second period T2", the number of lit light-emitting elements increases one by one in sequence, and finally, all the light-emitting elements D1 to D15 of the first light source 24 and the second light source 25 are lit.

[0094] In this way, the sequence control circuit 50 of the present embodiment can gradually light up the light-emitting elements of the second light source 25 by turning off the switches on the ground side among the switches SW1 to S13 one by one. In addition, the sequence control circuit 50 turns off the switches at regular time intervals (for example, period = T2 / 12) in the "second period T2", but is not limited thereto, and the switches can also be turned off in sequence at different time intervals. Here, for example, "one" light-emitting element of the second light source 25 corresponds to the "light-emitting part".

[0095] The turn signal lamp 10 of the present embodiment has been described above. The linear regulator 40 generates the drive current I1 for driving the first light source 24 in the "first period T1" and the "second period T2" each time the voltage Vbat is applied to the power supply line L1. In addition, the sequence control circuit 44 controls the switching regulator 41 to generate the drive current I2 in the "second period T2" of the "cycle Tx" when the voltage Vbat is applied to the power supply line L1. Moreover, in the present embodiment, in the "first period T1" when the number of lit light-emitting elements is small, the linear regulator 40 with a lower power conversion efficiency than the switching regulator is used. Thereby, in the "first period T1", the current value of the input current Iin can be made greater than the "lower limit value" of the "allowable range X". Thereby, it is possible to prevent false detection of a broken wire of the light source of the turn signal lamp 10.

[0096] In addition, in the "first period T1", the switch 42 is turned on, so that the current flows from the power supply line L1 through the resistor circuit 22. As a result, in the present embodiment, the current value of the input current Iin can be made more reliably greater than the "lower limit value".

[0097] In addition, in the "second period T2", the linear regulator 40 and the switching regulator 41 operate, and the power consumption in the turn signal lamp 10 increases. On the other hand, in the "second period T2", the switch 42 is turned off, so the supply of current from the power supply line L1 to the resistor circuit 22 is stopped. Thereby, it is possible to prevent the input current Iin from exceeding the "upper limit value" and suppress the power consumption in the turn signal lamp 10.

[0098] In addition, when there is a disconnection in the first light source 24 and the second light source 25, the extinguishing circuit 47 stops the operation of the linear regulator 40 and the switching regulator 41 and turns off the switch 42. Therefore, in this case, it is possible to suppress the useless power consumption generated in the turn signal lamp 10.

[0099] In addition, the number of light-emitting elements included in the second light source 25 ("13") is larger than the number of light-emitting elements included in the first light source 24 ("2"), so the power consumption of the second light source 25 is larger than that of the first light source 24. In the present embodiment, the linear regulator 40 with a lower power conversion efficiency (i.e., higher power consumption) than the switching regulator 41 for driving the second light source 25 with a larger driving power consumption is used to drive the first light source 24 with a smaller power consumption. Thereby, it is possible to easily make the current value of the input current Iin larger than the "lower limit value".

[0100] In addition, the sequential control circuit 44 can sequentially turn on a part of the light-emitting portions (light-emitting element D1) and the remaining light-emitting portions (light-emitting element D2) in the first light source 24 in the "first period T1".

[0101] In addition, the sequential control circuit 50 can sequentially turn on one by one the light-emitting elements among the light-emitting elements D3 to D15 of the second light source 25 in the "second period T2".

[0102] The above-described embodiment is for easy understanding of the present disclosure, and is not for limiting and interpreting the present disclosure. In addition, the present disclosure can be changed or improved without departing from its gist, and the present invention naturally includes its equivalents.

[0103] As part of the content constituting the present disclosure, the contents of Japanese Patent Application No. 2020-006662 filed on January 20, 2020, and Japanese Patent Application No. 2020-114844 filed on July 2, 2020 are incorporated by reference.

Claims

1. A lighting circuit, applicable to a lighting circuit for a vehicle direction indicator, which causes a first light source including at least one light-emitting element and a second light source including at least one light-emitting element to flash, and includes: A first regulator that supplies a prescribed first drive current to the first light source based on power from a power supply line during a first period in which the first light source is lit and the second light source is not lit, and during a second period in which the first light source and the second light source are lit, and stops supplying the first drive current to the first light source during a third period in which the first light source and the second light source are extinguished; A second regulator having a higher power conversion efficiency than the first regulator, which supplies a prescribed second drive current to the second light source based on power from the power supply line during the second period, and stops supplying the second drive current to the second light source during the third period; And A control circuit that repeatedly controls the second regulator at a prescribed period including the first period to the third period.

2. The lighting circuit according to claim 1, wherein It further includes a switching element that allows current from the power supply line to flow through a resistor during at least the first period of the first period and the second period.

3. The lighting circuit according to claim 2, wherein The switching element stops supplying current from the power supply line to the resistor during the second period.

4. The lighting circuit according to any one of claims 1 to 3 further includes: A first determination circuit that determines whether the output voltage of the first regulator is higher than a first prescribed value; A second determination circuit that determines whether the output voltage of the second regulator is higher than a second prescribed value; and An extinguishing circuit that stops the operation of the first regulator and the second regulator when the output voltage of the first regulator is higher than the first prescribed value or the output voltage of the second regulator is higher than the second prescribed value.

5. The lighting circuit according to any one of claims 1 to 3, wherein The power consumption of the second light source is greater than that of the first light source.

6. The lighting circuit according to any one of claims 1 to 3, wherein The first light source includes a plurality of light-emitting portions, The control circuit sequentially lights the plurality of light-emitting portions during the first period.

7. The lighting circuit according to any one of claims 1 to 3, wherein The second light source includes a plurality of light-emitting portions, The control circuit sequentially lights the plurality of light-emitting portions during the second period.

8. The lighting circuit according to any one of claims 1 to 3, wherein The first regulator is a linear regulator, The second regulator is a switching regulator.

9. A vehicle direction indicator includes: A first light source including at least one light-emitting element; A second light source including at least one light-emitting element; and A lighting circuit that causes the first light source and the second light source to flash, The lighting circuit includes: A first regulator supplies a first drive current to the first light source based on power from a power line during a first period in which the first light source is lit and the second light source is not lit, and during a second period in which the first light source and the second light source are lit, and stops supplying the first drive current to the first light source during a third period in which the first light source and the second light source are extinguished; A second regulator, which has a higher power conversion efficiency than the first regulator, supplies a second drive current to the second light source based on power from the power line during the second period, and stops supplying the second drive current to the second light source during the third period; and a control circuit repeatedly controls the second regulator at a prescribed cycle including the first period to the third period.

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