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    • 专利摘要:
    A controller (20) is provided, which is used with a light source (10) including a plurality of light emitting units (12_1 to 12_N) connected in series to configure a vehicle lamp (1). The controller (20) includes a current source (30) which is configured to supply a control current to the light source (10), and N branch circuits (40_1 to 40_N) (40_1 to 40_N) which are respectively provided in parallel with N light emitting units. Each of the branch circuits (40_1 to 40_N) comprises a bypass transistor (M1) which is provided in parallel with a corresponding light emitting unit, a feedback capacitor (C1) which is provided between the gate and the drain of the transistor of bypass (M1), and a gate control circuit (60) which is configured to output a control voltage between the gate is the source of the bypass transistor (M1), in accordance with a control signal.
    公开号:FR3018659A1
    申请号:FR1552042
    申请日:2015-03-12
    公开日:2015-09-18
    发明作者:Masayasu Ito；Takao Muramatsu；Syouhei Yanagidu
    申请人:Koito Manufacturing Co Ltd；
    IPC主号:
    专利说明:

    [0001] 186 5 9 1 CROSS REFERENCE TO ASSOCIATED APPLICATIONS This application claims the benefit of the priority of Japanese Patent Applications Nos. 2014-052540 and 2014-052541, both filed on March 14, 2014.
    [0002] TECHNICAL FIELD The present invention relates to a vehicle lamp used for an automobile or the like.
    [0003] BACKGROUND A vehicle lamp can generally switch between a low beam and a high beam. The dipped beam is intended to illuminate a nearby area with a predetermined lighting intensity and there are regulations relating to the distribution of light so as not to dazzle the oncoming vehicles or the preceding vehicles. The low beam is mainly used when the vehicle is traveling in an urban area. On the other hand, the high beam is intended to illuminate a wide range ahead and a remote area with a comparatively high illumination intensity. The main beam is used mainly when the vehicle is traveling on a road with few oncoming vehicles and preceding vehicles. That is, although the visibility of the high beam is greater than that of the passing beam for drivers, the high beam has a problem such that the high beam dazzles pedestrians or drivers of vehicles that are in front of this one. Adaptive driving beam (ADB) technology has recently been proposed to dynamically and adaptively control the light distribution pattern of a high beam based on the condition of the vehicle environment. ADB technology is designed to detect if there is a vehicle ahead, an oncoming vehicle or a pedestrian in front of it, and to remove the glare given to these vehicles and pedestrians, for example, by decreasing the light to radiate to the areas corresponding to the vehicle and pedestrians.
    [0004] A vehicle lamp including an ADB function will be described. Fig. 1 is a block diagram illustrating a vehicle lamp having an ADB function according to a comparative technique. It should be noted that this comparative technique should not be considered as the prior art. A vehicle lamp ir has a light source 10 and a control device 20r. In an ADB, a high beam lighting area is divided into N sub-areas (where N is a natural number). The light source 10 includes a plurality of light emitting units 12_1 to 12_N, which are respectively associated with the N sub-areas. Each light emitting unit 12 comprises a semiconductor device such as a light-emitting diode (LED) or a laser diode (DL) and is arranged to illuminate a corresponding sub-area. Each light emitting unit 12 may be a single device or may include a plurality of devices connected in series. The controller 20r controls the plurality of light emitting units 12-1 to 12_N so that the respective light emitting units are on or off, so as to change the light distribution of a high beam. Alternatively, the controller 20r performs pulse width modulation (PWM) control on the light emitting units 12 at a high frequency so as to adjust the effective brightness. The controller 20r includes a current source 30, a plurality of branch circuits 40_1 to 40_N, and a controller 50. The power source 30 receives a battery voltage VBAT (also referred to as a VIN input voltage) from a battery. 2 via a switch 4, and stabilizes a control current DM / for circulating in the light source 10 as a target value. The plurality of branch circuits 40_1 to 40_N are respectively associated with the plurality of light emitting units 12_1 to 12_N. Each branch circuit 40 is configured so that it can be switched between a ACIVE state and a DEACTIVATED state. If an i-th branch circuit 40_i goes into the ON state, the control current km / flows in the branch circuit 40_i and not in the light emitting unit 12_i, thereby turning off the light emitting unit 12_i. . On the other hand, if the branch circuit 40_i goes to the OFF state, the control current IoRy flows in the light emitting unit 12_i thereby turning on the light emitting unit 12_i. An upstream processor 6 (e.g., an electronic control unit (ECU)) for controlling the vehicle lamp 1r determines sub-areas that the high beam must illuminate based on the situation in front of the vehicle. The processor 6 then delivers a control command to the controller 50 of the control device 20r. The controller 50 controls the states of the branch circuits 40_1 to 40_N based on the control command from the processor 6. Specifically, the controller 50 selects the light-emitting units 12 corresponding to the sub-areas to be illuminated, and deactivates the branch circuits 40 parallel to the selected light emitting units 12 while activating the branch circuits 40 parallel to the other light emitting units 12.
    [0005] If a branch circuit 40 abruptly shifts from the OFF state to the OFF state, the output voltage VOUT of the current source 30 decreases. In the case where the power source 30 is configured according to the topology of a rear converter, a boost converter, an indirect transfer converter, a direct converter or the like having a high capacity smoothing capacitor intended to be connected in parallel with a charge, if the output voltage Vour decreases abruptly, the electric charge accumulated in the smoothing capacitor is released, so that the control current IoRy flowing on the side of the light emitting unit 12 is exceeded. On the other hand, if a branch circuit 40 is abruptly switched from the OFF state to the ON state, the control current Wu - is under under. If the width of the fluctuation of the control current IDRV followed by the activation or deactivation of a branch circuit 40 is large, the reliability of the light-emitting unit 12 is unfavorably modified or the noise component increases. . In particular, in the case where a plurality of branch circuits 40 are turned on or off at the same time, the fluctuation width of the output voltage / furnace increases and this problem becomes more remarkable. To solve this problem, a technology has been proposed for progressively switching the branch circuits 40 between the ON state and the DEALLED state (see JP-A-2008-126958).
    [0006] SUMMARY Figure 2 is a circuit diagram illustrating a branch circuit 40r examined by the inventors of the present invention. Similarly to 313-A-2008-126958, the branch circuit 40r includes a bypass transistor M1 which is provided in parallel with a light emitting unit 12 and a low pass filter (integration circuit) 42 which filters a control signal for ordering the activation or deactivation of the bypass transistor M1 and delivers the filtered control signal to the gate of the bypass transistor M1. A level shifter circuit 44 is provided in the input stage of the low pass filter 42. The low pass filter 42 is provided to gradually vary the gate voltage of the shunt transistor M1, thereby gradually switching the shunt transistor. M1 between state AL I IVÉ and state OFF. The inventors of the present invention have examined the branch circuit 40r of FIG. 2 including a shunt capacitor provided between the gate and the source of the bypass transistor M1 and have been able to discover the following phenomenon.
    [0007] FIG. 3 is a waveform diagram illustrating the operation of the vehicle lamp 1r comprising the branch circuit 40r of FIG. 2. When a control signal 51 is at the high level, a transistor Q1 of the shift circuit level 44 is in the activated state, and the VGs voltage between the gate is the source of the bypass transistor M1 becomes zero, so that the bypass transistor M1 is turned off. On the other hand, the current ILED flowing in the light emitting unit 12 becomes the control current IDRy which is generated by the current source 30, so that the light emitting unit 12 is activated.
    [0008] If the control signal 51 makes a transition to the low level at the time t0, the transistor Q1 of the level shift circuit 44 is activated and the voltage VAS between the gate is the source of the branch transistor M1 increases according to the constant of time of the low pass filter 42. After that, if the voltage VAS between the gate and the source exceeds a threshold voltage VTH for a voltage between the gate and the source of the MOSFET, the bypass transistor M1 is activated, so that the control current km / is extracted in the bypass transistor M1 and the current ILED flowing in the light emitting unit 12 decreases. Here, before a time t1, since the bypass transistor M1 is in the off state, the voltage between the drain and the source of the bypass transistor M1 is equal to the forward voltage Vf of the light emitting unit 12 and thus is in this state, even if the voltage VAS between the gate is the source of the bypass transistor M1 varies gradually, it may be impossible to gradually change the current flowing in the bypass transistor M1 and thus, it may be impossible to gradually change the current ILED flowing in the light emitting unit 12. With this configuration, to change more gradually the ILED current, it may be necessary to adjust the cutoff frequency of the low pass filter 42 so as to be lower (i.e., to adjust the time constant to be longer). However, in this case, the delay time z from the moment when the control signal S1 transitions until the current of the ILED LED begins to vary becomes longer. Moreover, since the smoothing capacitor has a large capacitance, to suppress the increase of the control current IDRy due to the control of activation or deactivation of the bypass circuit 40, it may be necessary to adjust the time of activation and deactivation time (generally referred to hereinafter as transition time) so as to have a considerable length. On the other hand, if the transition times are set to be excessively long, the switching loss increases and thus the efficiency decreases. On the other hand, in the case of using the branch circuit 40 to perform PWM dimming, if the duty cycle is low, the dimming accuracy decreases due to the influence of the transition times.
    [0009] These problems occur not only in the case of executing an ADB control but also in other cases such as the case of using the vehicle lamp 1r shown in Fig. 1 to control the brightness. Accordingly, one aspect of the present invention provides a vehicle lamp capable of progressively modifying the current flowing in a light emitting unit, and a vehicle lamp control device. Another aspect of the present invention provides a vehicle lamp capable of suppressing control current variation and a vehicle lamp controller.
    [0010] According to an illustrative embodiment of the present invention, there is provided a controller which is used with a light source including a plurality of light emitting units connected in series to configure a vehicle lamp. The controller includes: a current source that is configured to output a control current to the light source; and N branch circuits which are associated with N light-emitting units of the plurality of light-emitting units and respectively provided in parallel with the N light-emitting units and which are configured to be able to be switched independently between an ON state and a OFF state, where N is a natural number. Each of the branch circuits comprises: a bypass transistor which is provided in parallel with a corresponding light emitting unit; a feedback capacitor which is provided between the gate and the drain of the bypass transistor or between the gate and the collector of the bypass transistor; and a gate control circuit which is configured to output a control voltage between the gate is the source of the bypass transistor or between the gate and the emitter of the bypass transistor, in accordance with a control signal. According to the above configuration, the feedback capacitor is provided between the gate and the drain of the bypass transistor or between the gate and the collector of the bypass transistor. Consequently, due to a mirror effect, in a mirror section, the voltage VAS between the gate and the source or between the gate and the transmitter becomes flat in the vicinity of the threshold voltage VTH, and varies with a weak slope. It is therefore possible to gradually switch the bypass transistor between the ALI 1VÉ state and the DISABLED state and it is possible to progressively modify the current flowing in the light emitting unit. In the above control device, the gate control circuit may be configured such that a charge time constant and a discharge time constant for the gate capacitance of the bypass transistor and the feedback transistor are substantially equal. It is possible in this case to match the current slopes during the activation and deactivation of the bypass transistor. In the above control device, the gate control circuit may include a blocking element which is configured to limit the voltage between the gate and the source of the bypass transistor or between the gate and the emitter of the bypass transistor so that the voltage does not exceed a predetermined blocking voltage. The blocking voltage can be 1.5 times up to 3 times the threshold voltage of the bypass transistor. It is possible in this case to match the activation times and the deactivation times. In the above control device, the gate control circuit may include: a level shift circuit which is configured to receive the control signal and generate a control voltage so that the control voltage makes a transition between a voltage at the high level VH and 0 V; a current limiting resistor having one end connected to the gate of the bypass transistor and another end connected to the output terminal of the level shift circuit; and a diode which is provided in parallel with the current limiting resistor so that the anode of the diode is positioned at the gate side of the bypass transistor. In this case, the level shift circuit may include: an input transistor that is configured to be turned on or off based on the control signal; and a pair of voltage dividing resistors which has two resistors connected in series and is configured to divide the voltage of an end of the input transistor. Alternatively, the level shift circuit may include: a constant current source which is configured to be turned on or off according to the control signal; and a resistor that is configured to convert between current and voltage and is provided on the path of current that is generated by the constant current source. According to another illustrative embodiment of the present invention, there is provided a controller which is used with a light source including a plurality of light emitting units connected in series to configure a vehicle lamp. The controller includes: a converter that is configured to output a control current to the light source; N branch circuits which are respectively associated with N light-emitting units of the plurality of light-emitting units and provided in parallel with the N light-emitting units, and which are configured to be able to be switched independently between an ON state and a state DESALIED, where N is a natural number; and a controller that is configured to control the converter so that the control current approaches a predetermined target value TREF and controls the activation and deactivation of the N branch circuits. The converter comprises: a primary-side circuit which includes a switching transistor and a first inductor configured to accumulate energy upon switching of the switching transistor; a secondary side circuit which comprises a second inductor; and a coupling capacitor which has a capacitance C and is configured to couple the primary side circuit and the secondary side circuit. The TTRN transition time that is required to enable or disable the branch circuit satisfies the following expression (1): AV x C <TREF X TTRN ... (1) where AV is the difference of the output voltage of the converter between before and after the activation or deactivation of the branch circuit. Since the converter is configured by a topology having a coupling capacitor, a high capacity smoothing capacitor becomes unnecessary. Consequently, compared to a topology comprising a high capacity smoothing capacitor, it is possible to considerably reduce the transition times. Further, since the transition time TTRN is determined to satisfy the expression (1), the current for varying the output voltage Voin-AV can flow on the side of the branch circuit. It is therefore possible to prevent the control current from overtaking or under-overshooting. In the control device above, the following expression (2) can be satisfied: TREF X AV x T5w2i TTRN <L x (IMAx2 - IREF2) / 2 ... (2) where L is the inductance of the second inductor, ImAx is the maximum rated current of the light emitting units, and Tsw is the switching cycle of the switching transistor. In the case where one focuses on the switching cycle of the switching transistor of the converter, the current flowing in the second inductor comprises a ripple component of the switching cycle. In the case where the controller is configured to satisfy expression (2), it is possible to limit the maximum value of the current ripple so as to be smaller than the maximum rated current of the transmitter unit. of light, and it is possible to improve the reliability of the circuit. According to another illustrative embodiment of the present invention, there is provided a controller which is used with a light source including a plurality of light emitting units connected in series to configure a vehicle lamp. The controller comprises: a converter which is configured to output a control current to the light source, N branch circuits which are respectively associated with N light emitting units of the plurality of light emitting units and provided in parallel with the N light-emitting units and configured so that they can be independently switched between an ON state and a OFF state, where N is a natural number; and a controller that is configured to control the converter so that the control current approaches a predetermined target value TREF and controls the activation and deactivation of the N branch circuits. The converter comprises: a primary-side circuit which includes a switching transistor, and a first inductor configured to accumulate energy upon switching of the switching transistor; a secondary side circuit which includes a second inductor having an inductor L; and a coupling capacitor that is configured to couple the primary side circuit and the secondary side circuit. The following expression (2) is satisfied: IREF X AV x Tsw2i TTRN <L x (ImAx2 - IREF2) / 2 .-- (2) Where TTRN is a transition time required to enable or disable the branch circuit, AV is the difference of the output voltage of the converter between before and after the branch circuit activation or deactivation, MAX is the maximum rated current of the light emitting units, and Tsw is the switching cycle of the switching transistor. In the case where one focuses on the switching cycle of the switching transistor of the converter, the current flowing in the second inductor comprises a ripple component of the switching cycle. In the case where the controller is configured to satisfy the expression (2), it is possible to limit the maximum value of the current ripple so as to be less than the maximum rated current of the transmitter unit. of light, and it is possible to improve the reliability of the circuit. In the control device above, the first inductor may include a first magnetic element or may be a transformer. The second inductor may include a second magnetic element or may be a transformer. In the control device above, each of the branch circuits may include: a bypass transistor which is provided in parallel with a corresponding light emitting unit; a feedback capacitor which is provided between the gate and the drain of the bypass transistor or between the gate and the collector of the bypass transistor; and a gate control circuit which is configured to output a control voltage between the gate and the source of the bypass transistor or between the gate and the emitter of the bypass transistor, as a function of a control signal. According to yet another explanatory embodiment, there is provided a vehicle lamp including a light source which has a plurality of light emitting units connected in series, and the control device according to any one of the embodiments. described above, which is configured to control the light source. According to the above configuration, it is possible to gradually vary the current of each light emitting unit. It is also possible to suppress the variation of the control current. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be well understood and its advantages will be better understood on reading the detailed description which follows. The description refers to the following drawings, which are given by way of example. Fig. 1 is a block diagram illustrating a vehicle lamp having an ADB function according to a comparative technique; Fig. 2 is a circuit diagram illustrating a branch circuit examined by the inventors of the present invention; Fig. 3 is a waveform diagram illustrating the operation of a vehicle lamp having the branch circuit of Fig. 2; Figure 4 is a circuit diagram illustrating a branch circuit according to a first explanatory embodiment; Fig. 5 is a waveform diagram illustrating the operation of the branch circuit of Fig. 4; Fig. 6 is a perspective view illustrating a lamp unit including the vehicle lamp according to the first explanatory embodiment; Fig. 7 is a circuit diagram illustrating a branch circuit according to a first modification; Fig. 8 is a block diagram illustrating a vehicle lamp according to a second explanatory embodiment; Fig. 9 is a waveform diagram illustrating an operation of activating the branch circuit; and Fig. 10 is a waveform diagram illustrating a switching operation of a switching transistor.
    [0011] DETAILED DESCRIPTION Embodiments of the present invention will be described hereinafter with reference to the accompanying drawings. In the set of drawings, components, elements and processes identical or equivalent are represented by the same reference symbols and their description will not be repeated. On the other hand, these explanatory embodiments do not limit the invention and are explanatory, and all the features to be described in the explanatory embodiments and their combinations may not be essential features of the invention.
    [0012] In this description, a state where an element A is connected to an element B includes not only the case where the element A and the element B are connected physically and directly, but also the case where the element A and the element B are connected indirectly via another element which has substantially no influence on the electrical connection state of the element A and the element B or does not degrade the functions and effects which are made by the coupling of the element A and the element B. Similarly, a state or element C is provided between the element A and the element B comprises not only the case where the element A and element C or element B and element C are directly connected, but also the case where element A and element C or element B and element C are connected indirectly via another element that has no significant influence on the state of electrical connection of element A and element C or element B and element C or degrades by the functions and effects that are achieved by the coupling of element A and the element C or element B and element C. On the other hand, in this description, reference symbols 20 representing electrical signals such as a voltage signal or a current signal, or electrical elements such as a resistor or a capacitor, represent a voltage value, a current value, a resistance value or a capacitance value, if necessary. [First illustrative embodiment] Fig. 4 is a circuit diagram illustrating a branch circuit 40 according to a first explanatory embodiment. The branch circuit 40 is used in a control device 20 of FIG. 1. The configuration of a peripheral circuit of the branch circuit 40 will be briefly described with reference to FIG. 1. A vehicle lamp 1 comprises a source 10 and a controller 20. The light source 10 has a plurality of light emitting units 12_1 to 12_N connected in series. The controller 20 comprises a current source 30, N branch circuits 40_1 to 40_N (N is a natural number) and a controller 50.
    [0013] The current source 30 supplies a control current IDRy to the light source according to a target brightness. The current source 30 comprises, for example, a converter of the elevator type or of the step-down type and a control circuit for the converter. The control circuit can detect the control current Dm / and perform a feedback check on the switching state of the converter, so that the detected control current IDRy approaches a target value. The type of the converter and the current control method are not particularly limited and may use other known technologies. The N branch circuits 40_1 to 40_N are respectively associated with N light emitting units 12 of the plurality of light emitting units 12 and provided in parallel with the light emitting units 12. The branch circuit 40_i is configured to switch 15 between an ON state and a OFF state in response to a control signal Sl_i and form a bypass parallel to the light emitting unit 12_i when the branch circuit 40_i is in the ON state. During a normal lighting control period, according to respective instructions to enable or disable the 20 N light emitting units 12_1 to 12_N, the controller 50 controls the activation or deactivation of each of the N branch circuits 40_1 to 40_N . More specifically, the controller 50 performs a PWM on the control signal 51_i according to the target brightness of the light emitting unit 12_i, so as to switch the branch circuit 40_i in a PWM cycle, thereby performing a gradation of the light emitting unit 12_i. The configuration of a branch circuit 40 will be described with reference to FIG. 4. The branch circuit 40 comprises a bypass transistor M1, a feedback capacitor C1 and a gate control circuit 60. The bypass transistor M1 is provided in parallel with the light emitting unit 12. A line which is connected to the cathode of the light emitting unit 12 is called cathode line LK and a line which is connected to the anode of the unit light emitter 12 is referred to as anode line LA. The cathode line of the i-th branch circuit 40 is common with the (i + 1) -th branch circuit 40.
    [0014] The bypass transistor M1 is a metal-oxide-semiconductor field effect transistor (MOSFET) and the source of the bypass transistor MI is connected to the cathode line LK and the drain of the bypass transistor M1 is connected to the line D. anode LA. As a replacement for the MOSFET, an insulated gate bipolar transistor (IGBT) can be used. In this case, the term "source" may be replaced by the term "issuer" is the term "drain" may be replaced by the term "collector". The feedback capacitor C1 is provided between the gate and the drain of the bypass transistor M1. The capacitance of the shunt capacitor C1 is determined so as to provide a sufficient mirror effect to the shunt transistor M1. In general, the capacity between the gate and the drain decreases with the reactivity of the MOSFET and is thus avoided. However, as will be described below, in the first explanatory embodiment, the mirror effect is used voluntarily. The feedback capacitor C1 may preferably have a capacitance value of from several hundreds of pF to 1000 pF. The gate control circuit 60 outputs a VGS gate voltage between the gate and the source of the bypass transistor M1 in accordance with the control signal S1. In the first explanatory embodiment, the high level of the control signal S1 is associated with the activation of the light emitting unit 12 and the low level is associated with the deactivation of the light emitting unit 12. when the control signal S1 is high, the gate control circuit 60 sets the control voltage VGS between the gate and the source so as to deactivate the bypass transistor M1. On the other hand, when the control signal S1 is at the low level, the gate control circuit 60 sets a VH level voltage higher than the threshold voltage VTH to the VGS control voltage between the gate source, so as to activate the bypass transistor M1. The gate control circuit 60 comprises a level shift circuit 62, a current limiting resistor Ri and a diode D1. The level shift circuit 62 reverses the logic level of the control signal S1, thereby effecting a level shift towards the high voltage voltage VH and 0 V. The current limiting resistor Ri is provided between an output terminal 64 of the level shift circuit 62 and the gate of the bypass transistor M1, and limit the load current of the gate capacitance of the bypass transistor M1. The diode D1 is provided in parallel with the current limiting resistor R1, so that the anode is positioned on the gate side of the bypass transistor M1. The level shift circuit 62 comprises base resistors Rb1 and Rb2, an input transistor Q1, voltage division resistors Rd1 and Rd2 and a zener diode ZD1. The input transistor Q1 is a bipolar transistor PNP type and the base of the input transistor Q1 receives the control signal S1 through the base resistor Rb1. The base resistor Rb2 is provided between the base and the emitter of the input transistor Q1. The base resistors Rb1 and Rb2 produce the division of the control signal S1 and the supply voltage Vcc and their application to the input of the base of the input transistor Q1. The voltage dividing resistors Rd1 and Rd2 divide the collector voltage of the input transistor Q1 thereby generating the control voltage VAS on the output terminal 64. If the on-state resistance of the input transistor Q1 is set in order to be sufficiently weak, the voltage at the high level VH of the control voltage VAS is given by the expression (11). VH = (Vcc - VK) x Rd2 / (Rd1 + Rd2) (11) VK represents the potential of the cathode line LK. The zener diode ZD1 is provided between the output terminal 64 and the cathode line LK and acts as a blocking element which limits the control voltage VAS so that the control voltage VAS does not exceed a predetermined blocking voltage VCL. That is, the high level voltage VH becomes the lowest of the voltages given by the expression (11) and the blocking voltage VCL.
    [0015] The activation time of the bypass transistor M1 corresponds to the time which is necessary for the voltage VAS between the gate and the source to increase by 0 V up to the threshold voltage VTH and the deactivation time of the bypass transistor M1 corresponds to at the time that is necessary for the voltage VAS between the gate is the source decreases from the voltage at the high level VH up to the threshold voltage VTH. To match the activation time and the deactivation time, it may be necessary for the difference (VH - VTH) and the threshold voltage to be at the same level (0.5 times to 2 times). That is, it may be preferable to set the voltage at the high level VH, in other words, the blocking voltage Va, at 1.5 times up to 3 times the threshold voltage VTH.
    [0016] On the other hand, it may be preferable to determine the supply voltage Vcc of the level shift circuit 62 as a function of the configuration of the controller 20. For example, in an application in which the power source 30 of the FIG. 1 is a converter for generating a negative voltage and the voltage on the node OUTN + 1 is negative, it may be preferable to set the supply voltage Vcc at 5 V up to 10 V. In an application in which the source current 30 is a boost converter and an increased voltage is applied to a node OUT1, the supply voltage Vcc can be the increased voltage.
    [0017] In order for the gate control voltage VAS to transition between the high voltage VH and 0 V, it may be necessary to charge and discharge the gate capacitance (not shown) of the bypass transistor M1 and the capacitor. It may be preferable for the gate control circuit 60 to be configured so that the load time constant of the combined capacity of the gate capacitance and the feedback capacitor is substantially equal to the time constant for the gate capacitor. unload the combined capacity. In the gate control circuit 60 of Fig. 4, a path including the voltage dividing resistor Rd1 and the current limiting resistor R1 becomes a charge path, and a path including the diode D1 and the division resistor R1. Voltage Rd2 becomes a discharge path. Accordingly, the values of the resistances can be determined to satisfy the expression: Rd1 + R1. ZD1 + Rd2. ZD1 here represents the direct impedance of the diode D1. In the foregoing, the configuration of the branch circuit 40 has been described. The operation of the branch circuit 40 will then be described. FIG. 5 is a waveform diagram illustrating the operation of the branch circuit 40 of FIG. 4. For comparison, the waveform of the operation of the branch circuit 40r of FIG. 2 is represented by a line in FIG. mixed line. If the control signal S1 transitions to the low level at time t0, the input transistor Q1 is turned on and the gate voltage VGs begins to increase. After that, if the gate voltage Vis reaches the vicinity of the threshold voltage VTH of the MOSFET, the MOSFET goes into a weakly AL I IVE state, and the voltage Vps between the drain and the source begins to decrease. At this time, due to the mirror effect produced by the feedback capacitor C1, the gate receives a feedback from the drain and the rate of decrease of the voltage Vps between the drain and the source decreases, and the gate voltage Vis is maintained in the vicinity of the threshold voltage VTH, then increases very gradually. If the Vps voltage between the drain and the source decreases to an operating stabilization point, the gate does not receive feedback from the drain and the gate voltage Vis starts to increase with the original time constant. A section in which the gate voltage Vis varies gradually is called the mirror period Tm. The drain current Im1 flowing in the bypass transistor M1 is a function of the voltage Vis between the gate and the source and the voltage Vps between the drain. and the source. Accordingly, if the gate voltage Vis between the gate and the source and the Vps voltage between the drain and the source gradually vary, the drain current Iril also varies gradually. As a result, the current QED flowing in the light emitting unit 12 gradually decreases.
    [0018] If the control signal S1 makes a transition from high to time t1, the input transistor Q1 is turned off and the gate voltage Vis begins to decrease. After that, at the same time as the bypass transistor M1 is activated, the bypass transistor M1 is progressively deactivated by the mirror effect and accordingly, the ILED current flowing in the light emitting unit 12 increases progressively. The operation of the branch circuit 40 has been described in the foregoing. In accordance with the branch circuit 40, since the feedback capacitor C1 is provided between the gate and the drain of the bypass transistor M1, in the mirror section Tm, the voltage Vps between the drain and the source varies gradually, and the voltage Screw between the gate is the source becomes flat near the VTH threshold voltage and then varies with a slight slope. It is therefore possible to gradually switch the bypass transistor M1 between the AL I IVE state and the DISABLED state, and it is possible to make a gradual transition to the current ILED flowing in the light emitting unit 12. on the other hand, the gate control circuit 60 is configured such that the time constant of the load path of the gate capacitance of the bypass transistor M1 is substantially equal to the time constant of the discharge path of the gate capacitance . It is therefore possible to match the delays of the activation operation and the deactivation operation, and the slope of the ILED current. On the other hand, the zener voltage of zener diode ZD1 which is a blocking element is included in a range of 1.5 times to 3 times the threshold voltage VTH of the MOSFET. As a result, the voltage at the high level VH of the control voltage VAS becomes almost equal to the threshold voltage VTH and it is therefore possible to match the activation time and the deactivation time. According to the branch circuit 40, the activation time and the deactivation time can be set according to the time constants of the charge and discharge paths of the gate capacitance, i.e., the impedance ZD1 of the diode D1 and the resistors R1, Rd1 and Rd2. If the activation time and the deactivation time are excessively short, the suppression effect of overshoot and undershoot is reduced. On the contrary, if the activation time and the deactivation time are excessively long, the loss of the bypass transistor M1 increases. Accordingly, it may be preferable to set the activation time and the deactivation time so as to be short in a range in which it is possible to suppress overshoot and undershoot.
    [0019] An application of the lamp for vehicle 1 will then be described. Fig. 6 is a perspective view illustrating a lamp unit (lamp assembly) 500 comprising the vehicle lamp 1 according to the first explanatory embodiment. The lamp unit 500 comprises a transparent cover 502, a high beam unit 504, dipped beam units 506 and a housing 508. The vehicle lamp 1 described above can be used, for example, in the The high beam unit 504. The units of the plurality of light emitting units 12 are arranged in line, for example in the horizontal direction, so as to illuminate different areas. As the vehicle travels, areas to be illuminated are adaptively selected by a vehicle-side controller, for example, an electronic control unit (ECU). The vehicle lamp 1 receives data indicating the areas to be illuminated and activates the light source 10 (light emitting units 12) corresponding to the indicated areas. In the foregoing, one aspect of the present invention has been described with reference to the first explanatory embodiment. The present embodiment is illustrative, and those skilled in the art can understand that different modifications can be made by combinations of components and processes, and such modifications are also within the scope of the present invention. These modifications will be described below. (First modification) Fig. 7 is a circuit diagram illustrating a branch circuit 40a according to a first modification. The branch circuit 40a is different from that of FIG. 4 in the configuration of a level shift circuit 62a. The level shift circuit 62a comprises a constant current source 66, a resistance Rd3 for the conversion between the current and the voltage and a zener diode ZD1. The constant current source 66 may be switched between an ON state and a OFF state in response to the control signal S1 and generate a constant current Ic when in the ON state. The configuration of the constant current source 66 is not particularly limited and it is possible to easily configure a simple constant current source, for example, by connecting a resistor Re1 to the emitter of the input transistor Q1. If the base voltage of the input transistor Q1 when the control signal S1 is low is represented by VBL, the constant current Ic is expressed by the expression (12). Ic = {Vcc - (VBL + VBC)} / Re1 ... (12) VIL here represents the voltage between the base and the emitter of the input transistor Q1 and is a constant of about 0.6 V.
    [0020] The resistance Rd3 is provided on the path of the constant current Ic. The voltage drop (Rd3 x IC) of the resistor Rd3 is output as the control voltage VGs from the output terminal 64. The zener diode ZD1 blocks the control voltage VAS so that the control voltage VAS does not exceed the VCL blocking voltage. On the other hand, in the first modification, it may be preferable to determine a circuit constant so as to satisfy the expression: Vo_ <Rd3 X Ic. According to the first modification, it may be possible to obtain the same effects as those of the explanatory embodiment above. (Second modification) As a light source 10, in addition to LEDs, semiconductor light sources such as organic laser diodes (DL) and electroluminescent elements (EL) can be used. (Third modification) In the lamp unit 500 of FIG. 6, the case of the use of the vehicle lamp 1 shown in FIG. 3 in the high beam unit 504 has been described. However, alternatively or additionally, the vehicle lamp 1 may be used in the low beam units 506. [Second explanatory embodiment] Fig. 8 is a block diagram illustrating a vehicle lamp according to a second embodiment of the invention. explanatory realization. The vehicle lamp 1 comprises a light source 10 and a control device 20a. The light source 10 has a plurality of light emitting units 12_1 to 12_N which are associated with N sub-areas.
    [0021] The controller 20a includes a converter 30a, a filter 36, N branch circuits 40_1 to 40_N and a controller 50a. The configuration of the branch circuits 40 is not particularly limited, and the branch circuits 40 may be configured as shown in FIG. 4 or 7.
    [0022] Part of the converter 30a and the controller 50a corresponds to the current source 30 of the first explanatory embodiment. The converter 30a delivers a control current IDRy to the light source 10. The controller 50a comprises a current controller 52 and a bypass controller 54. The current controller 52 generates a pulse signal S2 so as to control the converter 30a of so that the control current IDRy approaches a predetermined target value IREF- The bypass controller 54 controls the activation and deactivation of each of the N branch circuits 401 to 40N. The filter 36 is provided between the converter 30a and the light source 10. The filter 36 eliminates the ripple component or the noise component of the output current kiff, and delivers the control current IDRy to the light source 10 The configuration of the converter 30a will be described. The converter 30a is a converter Cuk and comprises a switching transistor M11, a first inductor L11, a second inductor L12, a coupling capacitor C11, an input capacitor C12 and a detecting resistors R11. The input capacitor C12 can be omitted. The first inductor L11 may include a first magnetic element or may be a transformer, and the second inductor L12 may include a second magnetic element or may be a transformer. The detection resistor R11 is provided on the current flow path Iu-r which is generated by the converter 30a and produces a voltage drop proportional to the current IouT. The current controller 52 detects the current T 1 '(i.e., the control current ID R y) based on the voltage drop of the sense resistor R 11 and controls the bypass transistor M 1. It will be noted that in the converter Cuk, the output voltage Vou1 becomes negative. The input capacitor C12, the switching transistor M11 and the first inductor L11 configure a primary side circuit 32. A diode D11 and the second inductor L12 configure a secondary side circuit 34. The inductance of the second inductor L12 is represented by L. The primary side circuit 32 and the secondary side circuit 34 are coupled via the coupling capacitor C11 having a capacitance value C. The first inductor L11 accumulates energy when the switching transistor M11 is activated and releases the energy when the switching transistor M11 is deactivated. The released energy is transmitted to the secondary side circuit 34 via the coupling capacitor C11. This energy (current) is rectified by the diode D11 and the second inductor L12. The rate of increase or decrease of the output current of the converter 30a is determined as a function of the inductance Ls of the second inductor L12.
    [0023] If the output voltage difference between before and after the activation or deactivation of the branch circuit 40 is represented by AV, the transition time TTRN which is required to activate or deactivate the branch circuit 40 is determined so as to satisfy to expression (1). AV XC <TREF X TTRN --- (1) If the number of branch circuits 40 to be activated at the same time is represented by noN and the number of branch circuits 40 to be deactivated at the same time is represented by noFF, the difference of AV output voltage is obtained by the following expression: AV = I (noN - noFF) 1 x Vf. That is, the output voltage difference AV depends on the number of branch circuits 40 to be controlled at the same time. If the maximum value that the AV output voltage difference can be represented by AVMAX, the following relational expression (la) is obtained. It is assumed that at most k branch circuits among n branch circuits 40 may be switched at the same time between state AL I IVE and state OFF. In this case, when the k branch circuits 40 transition from the ON state to the OFF state, or from the OFF state to the ON state, the output voltage difference AV takes the maximum value. As a result, the maximum value at V.VmAx of the output voltage difference ΔV is obtained based on the forward voltage Vf which is obtained when the control current Tm / flows in a light emitting unit 12, by means of the following expression: AVmAx = kx Vf. On the other hand, as will be described below, since expression (1) is a condition for protecting light emitting units 12, in the case where all n branch circuits 40 can be switched to At the same time between the ON state and the OFF state, it becomes unnecessary to protect the light-emitting units 12, and thus, the expression (1) becomes unnecessary. Consequently, the maximum value AVmAx can be obtained in this case by means of the following expression: AVmAx = (n-1) x Vf. For example, in the case where the maximum value AVMAX is 50 V, the capacitance C of the coupling capacitor C11 is 1.0 pF and the predetermined target value IREF is 1.0 A, it may be preferable to set the TTRN transition time longer than 50 ps. On the other hand, the overcurrent suppression effect (described below) may be more efficient when the capacitance C of the capacitor C11 decreases and when the transition time TTRN becomes longer. However, if the capacitance C is excessively low, it becomes easy for the converter 30a to oscillate and the amount of power transmission from the primary side circuit 32 to the secondary side circuit 34 decreases, and thus the output power of the converter 30a decreases. On the other hand, if the TTRN transition time is set to be excessively long, the power loss of the branch circuits 40 increases and a delay occurs in the PWM gradation and the accuracy of the dimming decreases. Accordingly, it may be preferable to determine the TTRN transition time to satisfy expression (1) in view of performance and oscillation resistance. On the other hand, if the maximum rated current of the light emitting units 12 is represented by ImAx, the switching cycle of the switching transistor M11 is represented by Tsw and the inductance of the second inductor L12 is represented by Ls, the converter 30a is configured to satisfy the following expression (2). IREF X AV X Tsw21 TTRN <LS X (IMAX2 IREF2) / 2 .-. (2) In the foregoing, the configuration of the vehicle lamp according to the second explanatory embodiment has been described. The operation of the vehicle lamp will then be described. FIG. 9 is a waveform diagram illustrating the activation operation of branch circuit 40. In FIG. 9, (a) represents a case where expression (1) is satisfied and (b) represents a case where the expression (1) is not satisfied. In the converter Cuk, the voltage between the two ends of the coupling capacitor C11 becomes the output voltage VOUT. Accordingly, to vary the AV output voltage of AV, it is necessary to charge or discharge the coupling capacitor C11 of AV x C. Since the rate of change of AV is the transition time TTRN of each branch circuit 40, if the output voltage oven varies from AV during the TTRN transition time, the charging / discharging current IouT of the coupling capacitor C11 is expressed as follows.
    [0024] If the current R1 exceeds the predetermined target value IREF, the ILED current exceeding the predetermined target value IREF flows in the light source 10 and thus the light source 10 switches to the overcurrent state. Accordingly, as shown in (b) in Fig. 9, when the branch circuit 40 is deactivated at a high speed as a function of the transition time TTRN not satisfying the expression (1), the output current Jou- is in excess and overcurrent flows in the light emitting unit 12.
    [0025] On the other hand, if the capacitance C of the coupling capacitor C11 and the transition time TTRN are determined so as to satisfy the expression (1), even if the voltage between the two ends of the coupling capacitor C11 varies from AV, the current IouT does not exceed the IREF target value. It is therefore possible to suppress the overflow of the output current Yt and it is possible to prevent an overcurrent from circulating in the light emitting units 12. FIG. 10 is a waveform diagram illustrating a switching operation of the transistor M11 switching. The current variation as a function of the TTRN transition time of the branch circuit 40 shown in Fig. 9 is performed in a time scale of several tens of ps, while the current variation as a function of the switching of the bypass transistor M1 which will be described below is performed in a time scale as short as several ps. It is assumed that when the output current IouT of the converter 30a has remained stable at the target value IREF, according to the control of the branch circuit 40, the output voltage VOUT has decreased by AVMAX during the transition time TTRN. In this case, after switching of the branch circuit 40, in the primary side circuit 32 of the converter 30a, excess energy in accordance with AVMAX x IREF is generated. In the case where the current controller 52 performs a hysteresis check on the current km, if the output current Day exceeds the target value IREF, the switching stops. Consequently, the maximum period during which energy can be accumulated is equal to one switching cycle Tsw. During this switching cycle Tsw, the output voltage V 0 -r varies from AV '= AVMAX x Tsw / TTRN. That is, the excess energy WEx is given by the following expression (3).
    [0026] WD (= IREF X AV 'X Tsw = IREF XMAXX X TSW2 / TTRN --- (3) The excess energy WEx is transmitted from the primary side circuit 32 to the secondary side circuit 34 and causes the increase of the output current At this time, if the output current T0 increases from IREF to IpEAK, the expression (4) is established according to the law of conservation of energy WEx = L5 x (IpEAK2 - IREF2) / 2 ... (4) In order to ensure the reliability of the light emitting units 12, the IpEAK value of the increased current should simply be less than the maximum rated current MFI of the light emitting units 12.
    [0027] Accordingly, if expression (5) is satisfied, it can be ensured that the output current Tour is less than the maximum rated current of the light emitting units 12. WEX <L5 X (IMAX2 IREF2) / 2 ... (5 ) If the expression (3) is replaced by the expression (5), the expression 15 (2) is obtained IREF X AVmax X Tsw2 / TTRN <L5 X (IMAX2 IREF2) / 2 --- (2 That is, it is possible to protect the light emitting units 12 by designing the circuit so as to satisfy the expression (2). For example, in the case where AVMAX is equal to 50 V, IREF is equal to 1.0 A, Tsw is equal to 4 ps, TTRN is equal to 100 ps, and MAX is 1.2 A, Inductance Ls should simply be greater than 29 pH. On the other hand, when the inductance Ls of the second inductor L12 increases, it is possible to suppress an overcurrent or a noise component; however, the size of the inductor is increased and the cost of the component also increases. Therefore, in terms of size and cost, it may be preferable to set inductance Ls of second inductor L12 to a lower value in a range in which expression (2) is satisfied. Here, in the case where the filter 36 has an induction element, the variation of the output current Ion "- is suppressed by the combined inductance of the second inductor L12 and the induction element of the filter. the inductance of the second inductor L12 can be set to a value which is obtained by subtracting the inductance of the filter 36 from the value determined from the expression (2). The present embodiment is illustrative and those skilled in the art can understand that various modifications can be made by combinations of components and processes and these modifications also belong to the scope of the invention. The present invention will be described as follows: (Fourth modification) In the second explanatory embodiment, the Cuk converter has been described as an example However, the present invention is not limited thereto. The converter 30a only needs to have a topology comprising the primary-side circuit 32 including the first inductor L11 and the switching transistor M11, the secondary-side circuit 34 including the second inductor L12 and the coupling capacitor C11 configured to couple the primary-side circuit 32 and the secondary side circuit 34. For such a converter 30a, a Zeta converter or the like is known. A description has been made of the present invention with reference to the explanatory embodiments using specific terms. However, the explanatory embodiments described above represent only the mechanisms and applications of the present invention by way of example only, and are in no way intended to be interpreted restrictively. Alternatively, various modifications and alternative implementations may be made without departing from the spirit and scope of the present invention as defined in the appended claims.
    权利要求:
    Claims (14)
    [0001]
    REVENDICATIONS1. A control device (20) which is used with a light source (10) including a plurality of light emitting units (12_1 to 12_N) connected in series to configure a vehicle lamp (1), the control device ( 20) being characterized by comprising: a current source (30) which is configured to supply a control current to the light source (10); and N branch circuits (40_1 to 40_N) which are associated with N light emitting units of the plurality of light emitting units (12_1 to 12_N) and respectively provided in parallel with the N light emitting units and which are configured in order to be able to be switched independently between an AL I IVÉ state and a DISABLED state, where N is a natural number, wherein each of the branch circuits (40_1 to 40_N) comprises: a branching transistor (M1) which is provided in parallel with a corresponding light emitting unit; a feedback capacitor (C1) which is provided between the gate and the drain of the bypass transistor (M1) or between the gate and the collector 20 of the bypass transistor (M1); and a gate control circuit (60) which is configured to output a control voltage between the gate is the source of the bypass transistor (M1) or between the gate and the emitter of the bypass transistor (M1), in accordance with a control signal. 25
    [0002]
    The control device (20) of claim 1, wherein the gate control circuit (60) is configured such that a charge time constant and a discharge time constant for the gate capacitance of the transistor Bypass (M1) and the feedback transistor are substantially equal. 30
    [0003]
    The control device (20) according to claim 1 or 2, wherein the gate control circuit (60) comprises: a blocking element which is configured to limit the voltage between the gate and the source of the bypass transistor ( M1) or between the gate and the emitter of the bypass transistor (M1) so that the voltage 35 does not exceed a predetermined blocking voltage, andin which the blocking voltage is equal to 1.5 times up to 3 times the threshold voltage of the bypass transistor (M1).
    [0004]
    The control device (20) according to any one of claims 1 to 3, wherein the gate control circuit (60) comprises: a level shift circuit which is configured to receive the control signal and generate a control voltage so that the control voltage makes a transition between a high voltage VEi and 0 V; a current limiting resistor having one end connected to the gate of the bypass transistor (M1) and another end connected to the output terminal of the level shift circuit; and a diode which is provided in parallel with the current limiting resistor so that the anode of the diode is positioned on the gate side of the bypass transistor (M1).
    [0005]
    The control device (20) of claim 4, wherein the level shift circuit comprises: an input transistor which is configured to be turned on or off in accordance with the control signal; and a pair of voltage dividing resistors which has two resistors connected in series and is configured to divide the voltage of an end of the input transistor.
    [0006]
    The control device (20) according to claim 4, wherein the level shift circuit comprises: a constant current source which is configured to be turned on or off in accordance with the control signal; and a resistor which is configured to effect a conversion between current and voltage and is provided on the path of a current that is generated by the constant current source.
    [0007]
    A vehicle lamp (1) comprising: a light source (10) having a plurality of light emitting units (12_1 to 12_N) connected in series; andthe control device (20) according to any one of claims 1 to 6, which is configured to control the light source (10).
    [0008]
    A control device (20) which is used with a light source (10) including a plurality of light emitting units (12_1 to 12_N) connected in series to configure a vehicle lamp (1), the control device (20) comprising: a converter that is configured to output a control current to the light source (10); N branch circuits (40_1 to 40_N) which are respectively associated with N light-emitting units of the plurality of light-emitting units (12_1 to 12_N) and provided in parallel with the N light-emitting units, and which are configured for can be independently switched between an AL I IVÉ state and a DEACTIVATED state, where N is a natural number; and a controller that is configured to control the converter so that the control current approaches a predetermined target value IREF and controls the activation and deactivation of the N branch circuits (40_1 to 40_N), wherein the converter comprises: a primary side circuit which includes a switching transistor and a first inductor configured to accumulate energy upon switching of the switching transistor; a secondary side circuit which comprises a second inductor; and a coupling capacitor having a capacitance C and being configured to couple the primary side circuit and the secondary side circuit, and wherein the transition time TTRN that is required to activate or deactivate the branch circuit satisfies the following expression : AV x C <TREF x TTRN where AV is the difference of the output voltage of the converter between before and after the activation or deactivation of the branch circuit.
    [0009]
    9. Control device (20) according to claim 8, wherein the following expression is satisfied: TREF X AV x -rsW2 / TTRN <LX (ImAx2 - IREF2) / 2 where L is the inductance of the second inductor, 'MAX is the maximum rated current of the light emitting units (12_1 to 12_N), and Tsw is the switching cycle of the switching transistor.
    [0010]
    A control device (20) according to claim 8, wherein each of the branch circuits (40_1 to 40_N) comprises: a bypass transistor (M1) which is provided in parallel with a corresponding light emitting unit; a feedback capacitor (C1) which is provided between the gate and the drain of the bypass transistor (M1) or between the gate and the collector of the bypass transistor (M1); and a gate control circuit (60) which is configured to output a control voltage between the gate and the source of the bypass transistor (M1) or between the gate and the emitter of the bypass transistor (M1), depending a control signal.
    [0011]
    A vehicle lamp (1) comprising: a light source (10) including a plurality of light emitting units (12_1 to 12_N) connected in series; and the controller (20) according to any one of claims 8 to 10 which is configured to control the light source (10).
    [0012]
    A control device (20) which is used with a light source (10) including a plurality of light emitting units (12_1 to 12_N) connected in series to configure a vehicle lamp (1), the control (20) comprising: a converter that is configured to output a control current to the light source (10); N branch circuits (40_1 to 40_N) which are respectively associated with N light-emitting units of the plurality of light emitting units (12_1 to 12_N) and provided in parallel with the N light-emitting units and which are configured from so that it can be switched independently between a state AL I IVÉ and a state DEÉSAC I1VÉ, where N is a natural number; and a controller that is configured to control the converter so that the control current approaches a predetermined target value TREF and controls the activation and deactivation of the N branch circuits (40_1 to 40_N), wherein the converter comprises: a primary side circuit which comprises a switching transistor, and a first inductor configured to accumulate energy upon switching of the switching transistor; a secondary side circuit which includes a second inductor having an inductor L; and a coupling capacitor which is configured to couple the primary side circuit and the secondary side circuit, and wherein the following expression is satisfied: TREF X LW X TSW2 / TTRN <LX (ImAx2 - IREF2) / 2 where TTRN is a transition time required to enable or disable the branch circuit, AV is the difference in the converter output voltage between before and after the branch circuit is activated or deactivated, MAX is the maximum rated current of the emitting units of light (12_1 to 12_N), and Tsw is the switching cycle of the switching transistor.
    [0013]
    13. The control device (20) of claim 12, wherein each of the branch circuits (40_1 to 40_N) comprises: a bypass transistor (M1) which is provided in parallel with a corresponding light emitting unit; a feedback capacitor (C1) which is provided between the gate and the drain of the bypass transistor (M1) or between the gate and the collector of the bypass transistor (M1); and a gate control circuit (60) which is configured to provide a control voltage between the gate and the source of the bypass transistor (M1) or between the gate and the emitter of the bypass transistor (M1), in function of a control signal.
    [0014]
    A vehicle lamp (1) comprising: a light source (10) including a plurality of light emitting units (12_1 to 12_N) connected in series; and the controller (20) according to claim 12 or 13 which is configured to control the light source (10).
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    法律状态:
    2016-02-03| PLFP| Fee payment|Year of fee payment: 2 |
    2017-02-09| PLFP| Fee payment|Year of fee payment: 3 |
    2017-11-03| PLSC| Publication of the preliminary search report|Effective date: 20171103 |
    2018-02-07| PLFP| Fee payment|Year of fee payment: 4 |
    2019-02-07| PLFP| Fee payment|Year of fee payment: 5 |
    2020-01-30| PLFP| Fee payment|Year of fee payment: 6 |
    2021-01-27| PLFP| Fee payment|Year of fee payment: 7 |
    2022-02-09| PLFP| Fee payment|Year of fee payment: 8 |
    优先权:
    申请号 | 申请日 | 专利标题
    JP2014052541A|JP6282905B2|2014-03-14|2014-03-14|Vehicle light and drive device thereof|
    JP2014052540A|JP6283542B2|2014-03-14|2014-03-14|VEHICLE LIGHT AND DRIVE DEVICE THEREOF|
    JP2014052540|2014-03-14|
    JP2014052541|2014-03-14|
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