• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
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    • 专利摘要:
    A light emitting control device (2) has a power supply unit (10) which supplies a control current (Idr) to a light emitting element (31) which produces light emission from a light source. first function and light emission of a second function, a regulator (11) which regulates the control current so as to have a current value which is a function of a dimming voltage, and a dimming voltage generator ( 20, 20A, 20B) which generates the dimming voltage. The gradation voltage generator applies a voltage, obtained according to the resistance value of an externally connected resistor (Rc), to a voltage buffer (14), and regulates the output voltage of the voltage buffer as appropriate. effecting a light emission of one or the other of the first function and the second function, so as to generate the gradation voltage.
    公开号:FR3066875A1
    申请号:FR1854343
    申请日:2018-05-24
    公开日:2018-11-30
    发明作者:Kotaro Matsui；Yasushi Noyori
    申请人:Koito Manufacturing Co Ltd；
    IPC主号:
    专利说明:

    REFERENCE TO RELATED REQUESTS
    The present application is based on Japanese patent application No. 2017-102908, filed on May 24, 2017 with the Japanese Patent Office, and claims the priority of the latter.
    TECHNICAL AREA
    The present description relates to a light emission control device and to a vehicle light comprising the light emission control device and more particularly to dimming control.
    CONTEXT
    There are various lights such as, for example, a vehicle light which uses, as a light source, a semiconductor light emitting element such as for example a light emitting diode (LED) or a laser diode.
    In addition, there are vehicle lights with various functions, such as, for example, a high beam, a daytime running light (DRL, from the English "daytime running lamp"), a clearance light (CLL, from the English "clearance lamp"), a rear light and a stop light, for example, the quantity of light and the state of distribution of the light intensities of these are designed according to their function.
    Japanese patent publication pending examination No. 2010-015752 describes a lighting control device which controls the ignition of a plurality of lamp units having different functions. SUMMARY In some cases, for example, an LED that serves as a light source is used for a plurality of functions. For example, a light source device, designed with one or more LEDs, serves two functions such as daytime running light and clearance light or serves two functions such as taillight and brake light.
    When the same light source is used to fulfill a plurality of functions, in this way, a gradation can be achieved depending on the function. In other words, the quantity of light to be emitted is modified according to the function. Furthermore, in the case where a control substrate, on which is placed an electronic component as a light emission control device, and a light source substrate, on which is mounted a light source such as an LED, are designed as separate substrates, in order to improve the versatility of the light emission control device, dimming can be performed depending on the light source substrate to be connected to it. For example, there is a configuration in which a dimming resistor is placed on the light source substrate, and dimming control on the light emitting controller side is performed using a resistance value of it.
    In the case where a gradation according to these two functions and a gradation according to the light source substrate to be connected are envisaged, these respective gradation operations should be carried out, in an appropriate manner. More precisely, it is necessary, for example, to avoid a modification of the gradation ratio for each function by a resistance on the substrate side of the light source. In addition, an efficient configuration allowing each gradation is also required.
    Consequently, the present description aims to propose an effective configuration of a light emission control device which is capable of carrying out each dimming in an appropriate manner. SUMMARY A light emission control device according to the present description comprises a current supply unit, designed to supply a control current as a first current to a light emitting element, so as to make realize to the light emitting element emitting light of a first function, and for providing a control current as a second current which is less than the first current, to the light emitting element, so as to cause to the light emitting element the emission of light of a second function, a dimming voltage generator designed to apply a voltage, obtained as a function of a resistance value of an external resistance connected, to a buffer of voltage, and to vary an output voltage of the voltage buffer according to whether the light emitting element has to produce light emission from either of the first function and the second function, so as to produce a dimming voltage, and a regulator adapted to regulate the control current to the first current or to the second current, depending on the dimming voltage.
    In certain cases, the external resistance is connected so as to adjust the control current as a function, for example, of the row of light flux on the light source device side comprising the light emitting element, so that a value of voltage determined by the external resistor can be adjusted to the dimming voltage. In addition to this dimming, in the case of a different dimming of the light emitting element between the first function and the second function, the voltage value determined by the external resistance is acquired by means of the voltage buffer, and its voltage varies depending on whether a light emission operation is the first function or the second function, and is set to dimming voltage.
    In the light emission control device, it is considered that the regulator is designed to regulate the control current by means of a dimming signal by PWM, in addition to the dimming voltage, and that the dimming signal by PWM is supplied to the regulator when the light emitting element is made to emit the light of the second function.
    In other words, the dimming regulation is achieved by cooperation of a dimming (control current regulation) by means of the dimming voltage and a dimming (control current regulation) by means of 'a dimming signal by PWM.
    In the light emission control device, it is considered that the dimming voltage generator generates the dimming voltage which varies according to a resistance value of a temperature sensor.
    In this case, the dimming voltage also acts as a control current regulation voltage for the purpose of derating according to the temperature. In the light emission control device, it is considered that the dimming voltage generator is designed to prevent the dimming voltage from varying as a function of the resistance value of the temperature sensor, when it is arranges for the light emitting element to emit the light of the second function.
    In other words, during the second function where the light emission attack is carried out with the second weaker current, the mismatch according to the temperature is stopped.
    In the light emission control device, it is considered that the first function is an emission of light as a daytime running light and the second function is an emission of light as a clearance light, or that the first function is an emission of light as a stop light and the second function is an emission of light as a rear light.
    A vehicle light according to the present description includes a light source device comprising the light emitting device and the light emission control device.
    According to the present description, as soon as a dimming voltage is obtained by variation of the output voltage of the voltage buffer which reflects the resistance value of the external resistance, depending on whether it is necessary to produce a light emission of one or the other of the first function and of the second function, it is possible that the gradation ratio according to the function is not unchanged by the external resistance. Therefore, it is possible to perform a dimming control of both the dimming according to the external resistance and the dimming according to the function, by means of an efficient configuration.
    The foregoing summary is purely illustrative and is not intended to be limiting. In addition to the aspects, embodiments and features described above by way of illustration, other aspects, embodiments and features will be apparent from the drawings and the following detailed description.
    BRIEF DESCRIPTION OF THE DRAWINGS
    Figure 1 is a circuit diagram of a first illustrative embodiment of the present description.
    Figure 2 is a block diagram of the configuration of a regulator according to the illustrative embodiment.
    Figure 3 is a circuit diagram of a first comparative example.
    Figures 4A and 4B are explanatory graphs of the setting range of a coding resistor.
    Figures 5A and 5B are explanatory graphs of a gradation signal by PWM.
    Figure 6 is a circuit diagram of a second comparative example. Figure 7 is a circuit diagram of a second illustrative embodiment.
    Figure 8 is a circuit diagram of a third illustrative embodiment.
    Figure 9 is a circuit diagram of a fourth illustrative embodiment.
    DESCRIPTION OF EMBODIMENT <First illustrative embodiment> A vehicle light according to an illustrative embodiment is described below with reference to the drawings.
    As illustrated in FIG. 1, the vehicle light 1 according to the illustrative embodiment comprises a light emission control device 2 and a light source device 3.
    The vehicle light 1 performs the emission of light of a first function and a second function, by means of a common light source. An example is described here in which the first function is a daytime running light and the second function is a clearance light. In addition, the two functions are not limited to the daytime running light and the clearance light, and a plurality of other functions can be called upon, such as, for example, a brake light and a rear light.
    The light emission control device 2 is designed with various electronic components arranged on a 2K control substrate, for example. In addition, the light source device 3 is formed such that one or more light emitting element (s) is or are disposed on a 3K light source substrate which is a substrate different from the 2K control substrate described above. Here, in one example, three LEDs 31 are used as light emitting elements. However, the light emitting elements are not limited to the LEDs 31, and for example, laser diodes are also envisaged. In addition, the light emitting elements may be 1 in number, and various configurations for mounting in series or in parallel are envisaged when use is made of a plurality of light emitting elements. In the light source device 3, three LEDs 31 are connected in series between terminals 41 and 42 placed on the light source substrate 3K. Therefore, the control current Idr which is regulated by constant current, is supplied from the light emission control device 2 to the three LEDs 31, so that the LEDs 31 are controlled to emit light.
    In addition, an encoding resistor Rc is connected to the light source device 3, between the terminal 43 and a terminal 44 on the light source substrate 3K.
    Furthermore, the coding resistor Rc is a resistor intended for adjusting the control current which is provided as a function of the light emitting elements. The steady-state value of the control current Idr differs according to the type of light source, the number of light-emitting elements or the rank of the light flux. Therefore, the coding resistor Rc is arranged as an adjustment element, so as to allow an appropriate value of control current to be obtained, according to a light source configuration of the light source device 3.
    Thus, because the coding resistance Rc is based on a configuration of the light emitting elements, it is usually mounted on the side of the light source device 3. More precisely, the coding resistance Rc is an external resistance of the light emission control device 2.
    The light emission control device 2 is designed to receive energy supplied from a vehicle battery 90, at a position located between a terminal 25 or 26 and a TJ terminal placed on the control substrate 2K.
    A first switch 91 is inserted between a positive electrode terminal of the battery 90 and the terminal 25 of the light emission control device 2, and a second switch 92 is also inserted between the positive electrode terminal of the battery 90 and the terminal 26 of the light emission control device 2. The terminal 27 on the control substrate 2K is connected to a negative terminal side of the battery 90 via a point of mass.
    The first switch 91 is a switch which activates the first function by means of an SI signal. Assuming that "daytime running light" is the first function, the first switch 91 is made conductive by the signal SI, as a function, for example, of the switching on of the ignition ignition of the vehicle.
    The second switch 92 is a switch which activates the second function by means of a signal S2. Assuming that "clearance light" is the second function, the second switch 92 is made conductive by the signal S2 corresponding, for example, to the actuation of a vehicle width indicator light by an occupant (or to the command vehicle width lights).
    Furthermore, the first function and the second function are executed exclusively. The lighting of the daytime running light is executed in response to the switching on of the ignition switch, but switches to the lighting of the clearance light, in response to the lighting of vehicle width lights, even at the time of l '' ignition switch on. Thus, for example, when the first switch 91 and the second switch 92 are both made conductive, the second function takes priority.
    As described above, the ignition / extinction of the vehicle fire 1 and the functions section are controlled by the passage to the driver / blocked state of the first switch 91 and the second switch 92.
    In the light emission control device 2, the terminals 25 and 26 are connected to a function detector 12. The function detector 12 determines whether any instruction from among an extinction, first function and second function is currently given, by detecting the voltage values of terminals 25 and 26.
    Furthermore, although this is not illustrated, the light emission control device 2 can be designed to be put in communication with an electronic control unit (UCE, or ECU for "Electronic Control Unit" in English)) which provides electrical control on the vehicle side. In this case, a configuration is also envisaged which makes it possible to connect a supply voltage line and a ground line from the battery 90 to be connected to terminals 25, 26, 27, by means of the UCE unit and which allows the ECU to control the power supply to the light emission control device 2.
    In the light emission control device 2, a battery voltage supplied at terminals 25 and 26 is applied to a direct current / direct current converter 10 via an OR diode circuit consisting of diodes DI and D2.
    The direct current / direct current converter 10 is a current supply unit which supplies the control current Idr to the LED 31 of the light source device 3.
    The direct current / direct current converter 10 is for example a switching regulator. It is considered that the direct current / direct current converter 10 is of any type among a step-up type, a step-down type, and a step-up and step-down type, although this is a function of a relationship between a light source configuration (for example, the direct voltage drop) of the light source device 3 and a supply voltage by the battery 90.
    The direct current / direct current converter 10 performs a voltage conversion when it receives a direct voltage from the battery 90, and generates an output voltage Vdr. The output voltage Vdr appears between terminals 21 and 22 located on the control substrate 2K by means of a current detection resistor Rs and a dimming switch 13. [0054] Between the control substrate 2K and the light source substrate 3K, the connection between terminal 21 and terminal 41 and the connection between terminal 22 and terminal 42 are made by means of a beam. Consequently, the control current Idr which is based on the output voltage Vdr appearing on the output side of the direct current / direct current converter 10, flows according to the following sequence: terminal 21 - * terminal 41 - "the three LEDs 31 - »· Terminal 42 terminal 22.
    A regulator 11 performs a voltage conversion operation of the direct current / direct current converter 10 and performs regulation by constant current of the control current Idr.
    For example, the regulator 11 detects a current value of the control current Idr on the basis of the result of detection of the potential difference (target control voltage VCTL) between one end and the other end of the resistance of current detection Rs with two terminals 51 and 52. Then the regulator 11 compares the detected current value of the control current Idr with a target current value, and produces a switching control signal Spwm which is a PWM signal corresponding to the difference. The regulator 11 delivers the switching control signal Spwm from a terminal 56 to a switching converter switching element which is the direct current / direct current converter 10, to control the voltage conversion operation and carry out the output of constant current.
    In addition, a dimming voltage Vdm generated by a dimming voltage generator 20 is supplied to a terminal 54 of the regulator 11. The regulator 11 increases or decreases the target current value as a function of the dimming voltage Vdm, whereby the dimming command is executed. In addition, a terminal 55 to which is applied a dimming signal by pulse width modulation (PWM, or PWM for "Puise Width Modulation") SP, to be described later, can be prepared in the regulator 11 When the PWM dimming signal is applied to this terminal, a dimming command is executed based on the duty cycle of the PWM dimming signal pulses.
    In addition, the regulator 11 can output a dimming switching control signal SSW, from a terminal 53 to the dimming switch 13, based on the dimming signal by PWM SP.
    When the dimming switch 13 switches to the conductive state, the control current Idr is supplied to the LED 31. The dimming switch 13 is set to the conductive state and blocked by the control signal from SSW dimming switching, whereby dimming can be achieved.
    An example of a schematic configuration of such a regulator 11 is illustrated in FIG. 2.
    The regulator 11 detects the voltage difference between the two ends of the current detection resistor Rs (target control voltage VCTL) by means of a current detection amplifier 70. An error amplifier 71 obtains a error signal Ve taking the difference between the target control voltage VCTL and a reference voltage signal Vref produced by a reference voltage generator 72.
    The error signal Ve is compared to a comparison signal Vcp, produced in a comparison signal generator 74, by an error comparator 73. The comparison signal Vcp is for example a sawtooth signal . Consequently, the switching control signal Spwm having a duty cycle of the pulses which is a function of a current error quantity is obtained from the error comparator 73. The switching control signal Spwm is supplied from the terminal 56 to the direct current / direct current converter 10 via an AND gate 75, and the switching element of the direct current / direct current converter 10 is controlled to switch to the conductive and blocked state, which promotes a stabilization of the output current.
    For example, when the regulator 11 adopts such an output stabilization configuration, the dimming regulation can be achieved by the following method.
    For example, the reference voltage generator 72 generates the reference voltage Vref as a function of the dimming voltage Vdm applied from the terminal 54. More specifically, the reference voltage generator 72 sets the dimming voltage Vdm to the reference voltage Vref without exceeding the upper limit of the voltage value of the reference voltage Vref, or performs a processing such as, for example, a division of the dimming voltage Vdm or a multiplication of coefficient to generate the reference voltage Vref. In this way, the stabilization target value is changed, and the dimming control, i.e. current regulation to increase or decrease the control current Idr becomes possible.
    In addition, in this example, although the reference voltage Vref is modified, as a function of the regulation voltage Vdm, a positive offset or a negative offset can be applied to the comparison signal Vcp produced by the unit of generation of comparison signals 74, or a positive offset or a negative offset can be applied to the detection signal Vd or to the error signal Ve.
    Although the above method is an example in which the output current of the DC / DC converter 10 is lowered in a DC mode, the average current of the DC / DC converter 10 can be lowered depending of the PWM dimming signal described above.
    When the dimming signal by MLI SP is applied to terminal 55, a signal generator 76 produces a gate control signal Sgt and supplies the latter to the AND gate 75. The dimming signal by MLI SP can be used as door control signal Sgt. Thus for example, the period during which the dimming signal by PWM SP is at a low level (level L) is adjusted to a period of stop of the converter during which the switching control signal Spwm is not supplied to the converter. direct current / direct current 10 and the control current Idr does not flow. In this way, gradation becomes possible by means of the duty cycle of the gradation signal by MLI SP. In addition, the switching control signal Spwm corresponds to a frequency which is sufficiently higher than the dimming signal by PWM SP.
    In addition, the signal generator 76 produces the dimming switching control signal SSW on the basis of the dimming signal by MLI SP, and supplies it from terminal 53 to the dimming switch 13. Thus for example , the period during which the dimming signal by PWM SP is at level L can be adjusted to the period during which the control current Idr with the contribution of 1 does not flow to the LED 31, and the dimming can be carried out at by means of the duty cycle of the dimming signal by MLI SP.
    In addition, although the dimming control by means of the dimming signal by PWM SP is possible as described above, the first illustrative embodiment of Figure 1 illustrates an example in which the dimming signal by MLI SP is not used. Therefore, in the case of the first illustrative embodiment, it is also envisaged that the regulator 11 is not provided with terminals 55 and 53, the signal generator 76 and the AND gate 75.
    In the first illustrative embodiment, the regulator 11 performs the dimming control on the basis of the dimming voltage Vdm applied to the terminal 54.
    The dimming voltage generator 20 is described below again with reference to FIG. 1.
    The dimming voltage generator 20 includes a voltage buffer 14, a switch corresponding to functions 15 and resistors RI, R2 and R3.
    The voltage buffer 14 is designed with an operational amplifier which is connected as a voltage follower. The resistor RI and the terminal 23 are connected to a non-inverting input terminal of the voltage buffer 14. A voltage Vcc is applied to the other end of the resistor RI. In addition, between the control substrate 2K and the light source substrate 3K, the connection between terminal 23 and terminal 43 and the connection between terminal 24 and terminal 44 are made by means of a beam. Terminal 24 is connected to ground.
    Thus, the resistance RI and the coding resistance Rc are directly connected between the voltage Vcc and the ground, and a voltage which is obtained by dividing the voltage Vcc by the resistance RI and the coding resistance Rc, is applied to the non-inverting input terminal of the voltage buffer 14.
    Consequently, a buffer output voltage Vcb corresponding to the divided voltage is obtained as an output of the voltage buffer 14 with the gain of 1. The resistors R2 and R3 as well as the switch corresponding to functions 15 are connected in series between an output terminal of the voltage buffer 14 and earth. The switch corresponding to functions 15 is for example an N-channel semiconductor metal-oxide field effect transistor and switches to the conductive and blocked state when a gate voltage depending on the function is applied from the function detector 12 to his grid. More precisely, when the first function is determined, the switch corresponding to functions 15 switches to the blocked state, and when the second function is determined, the switch corresponding to functions 15 switches to the conducting state.
    Consequently, a voltage at the connection point of the resistors R2 and R3 is supplied, as the dimming voltage Vdm, to the terminal 54 of the regulator 11. Thus, during the first function, the dimming voltage Vdm becomes substantially equal to the voltage value of the buffer output voltage Vcb, and during the second function, the dimming voltage Vdm is equal to the voltage value obtained by dividing the buffer output voltage Vcb at l using resistors R2 and R3.
    The dimming voltage Vdm is determined by the presence or absence of the voltage divided by the resistors R2 and R3, on the basis of the buffer output voltage Vcb, determined according to the coding resistance Rc.
    Thus, as a dimming voltage Vdm, a voltage value which governs the control current Idr (first current) during the first function and a voltage value which governs the control current Idr (second current) during the second function are defined by resistors R2 and R3. In other words, the gradation ratio of the first function and the second function is defined by the resistors R2 and R3.
    Here, in order to explain the effect of the configuration of the first illustrative embodiment, a comparative example will be taken into account. FIG. 3 illustrates a vehicle light 100 comprising a light emission control device 200 and a light source device 300 as a first comparative example. Furthermore, in the comparative example and in the illustrative embodiment to be described below, the same components of circuits as those of FIG. 1 will be designated by the same reference numerals, a repetitive description will be omitted and only different elements will be described. In the first comparative example, a control substrate 200K and a light source substrate 300K are also separate members, and the coding resistor Rc is mounted on the light source substrate 300K.
    In the control substrate 200K of the light emission control device 200, the dimming voltage Vdm is adjusted to a voltage as a function of the coding resistance Rc, and the gradation in accordance with the first function and the second function is performed by means of the dimming signal by MLI SP.
    Consequently, the voltage which is obtained by dividing the voltage Vcc by the resistor RI and the coding resistor Rc is supplied, as the dimming voltage Vdm, to terminal 54 of the regulator 11.
    In FIG. 4B, the horizontal axis represents the dimming voltage Vdm and the vertical axis represents the target control voltage VCTL, but the range of dimming by the resistance Rc is for example a range RG3 in FIG. 4B .
    Furthermore, in the case of the first comparative example, the function detector 12 produces ie gradation signal by PWM SP depending on whether it is the first function or the second function which is determined, and ie supplies to terminal 55 of the regulator 11. For example, as illustrated in FIG. 5A, the function detector 12 continuously supplies a signal which is at a high level (level H), to the regulator 11, during the first function, and supplies the signal dimming by MLI SP to regulator 11, during the second function.
    Thus, the switching control signal Spwm of FIG. 2, for example, is supplied continuously to the switching element of the DC / DC converter 10, via the AND gate 75, during of the first function, but the converter stop period, during which the application of the switching control signal Spwm ceases and the dimming switch 13 goes into the blocked state, is generated during the second function. In other words, this period is the period when the gradation signal by MLI SP is at level L.
    Therefore, after the gradation as a function of the coding resistance Rc has been carried out, a gradation command is executed according to a gradation ratio determined by the duty cycle of the pulses of the gradation signal by MLI SP, during of the first function and the second function.
    However, when the gradation during the first function and the second function is carried out using the dimming signal by PWM SP, a problem of degradation of the emission noise occurs due to a rapid variation current. In addition, when the gradation ratio of the first function and the second function is high, ie the conduction duty cycle during the second function is considerably reduced. In this case, the reproducibility of the waveforms may deteriorate and for example, flickering of the light source may occur.
    Consequently, when it is considered that the dimming control of the dimming signal by MLI SP is not carried out, a second comparative example of FIG. 6 is envisaged. In this case, the light emission control device 200 connects the resistors RI and R30 and the switch corresponding to functions 15 in series between the voltage Vcc and the ground. Consequently, the light emission control device 200 connects the connection point of the resistor RI and of the resistor R30 to terminal 54 of the regulator 11 and to terminal 23 of the control substrate 200K. Thus, the coding resistor Rc is connected in parallel to the resistor R30.
    In this case, the dimming voltage Vdm is a voltage value which reflects the resistance value of the coding resistor Rc and the on / off state of the switch corresponding to functions 15.
    However, in this case, the gradation ratio of the first function and the second function is modified by the resistance value of the coding resistance Rc. This is due to the fact that the division ratio making it possible to obtain the dimming voltage Vdm differs as a function of the coding resistance Rc.
    Consequently, the configuration of the first illustrative embodiment shown in Figure 1 becomes appropriate.
    More specifically, a buffer output voltage Vcb which is the reference reflecting the coding resistance Rc can be obtained via the voltage buffer 14, and the dimming ratio of the first function and the second function (the voltage ratio of the dimming voltage Vdm) can be determined on the basis of the buffer output voltage. Therefore, the dimming voltage Vdm of the first illustrative embodiment reflects the resistance value of the coding resistor Rc, and in the case of the first function and the second function, the dimming voltage Vdm, to which the ratio gradation is constant, can be obtained independently of the coding resistance Rc. It is then possible, by not using the dimming signal by MLI SP, to solve the problem caused when using the dimming signal by MLI SP described above.
    In FIG. 4A, the horizontal axis represents the dimming voltage Vdm and the vertical axis represents the target control voltage VCTL, as in FIG. 4B. In the case of the first illustrative embodiment, the range adjustable by the coding resistor Rc is a range RG1. This is because when a range RG2 is set, the gradation ratio of the first function and the second function is a function of the coding resistance Rc. <Second illustrative embodiment> [0098] FIG. 7 illustrates a vehicle light 1 according to a second illustrative embodiment. The difference with the first illustrative embodiment shown in FIG. 1 lies in the fact that the regulator 11 regulates the gradation by additionally using the dimming signal by PWM SP applied to terminal 55.
    During the first function, the function detector 12 switches the switch corresponding to functions 15 to the blocked state, and continuously supplies a level H signal to terminal 55 of the regulator 11, as well as illustrated in Figure 5A. In addition, during the second function, the function detector 12 switches the switch corresponding to functions 15 to the conductive state, and also provides the dimming signal by PWM SP having a predetermined duty cycle at terminal 55 of regulator 11, as illustrated in FIG. 5A.
    More precisely, during the first function, only a DC gradation on the basis of the dimming voltage Vdm is used, and during the second function, the DC gradation on the basis of the gradation voltage Vdm and PWM gradation based on the PWM dimming signal SP are used together.
    By this means, while maintaining a constant gradation ratio of the first function and the second function, without using the coding resistor Rc (i.e., while maintaining high current accuracy from both the first function and the second function), during the second function, it is possible to apply the DC dimming to the guaranteed minimum current of the LED 31 and also to apply the PWM dimming. In this way, it is possible to lower the current to a low value, even by maintaining the high time of the output voltage Vdr to a certain extent.
    For example, the solid line in FIG. 5A indicates a case where the high time is very short in the first comparative example of FIG. 3. In the case of the second illustrative embodiment, even if the high time is maintained to a certain extent, as indicated by the broken line, by lowering the control current Idr by DC gradation, it is possible to obtain the same level of gradation as in the case of the solid line.
    Consequently, in the second illustrative embodiment, it is possible to obtain a high gradation ratio which cannot be reproduced in the first comparative example. c Third illustrative embodiment> A third illustrative embodiment is described below with reference to FIG. 8. The light emission control device 2 of the third illustrative embodiment is an example in which a generator dimming voltage 20A having a temperature-based mute function is set up. A configuration other than that of the dimming voltage generator 20A is identical to that of FIG. 1 or 7.
    The dimming voltage generator 20A includes voltage buffers 14 and 18, the switch corresponding to functions 15, resistors RI, R2, R3, RIO and Rll, diodes D10 and DU and a thermistor Rth.
    The voltage buffers 14 and 18 are designed with an operational amplifier which is connected as a voltage follower.
    As in FIG. 1, the resistor RI and the terminal 23 are connected to the non-inverting input terminal of the voltage buffer 14, and the voltage Vcc is applied to the other end of the resistor RI. Consequently, the voltage which is obtained by dividing the voltage Vcc by the resistance RI and the coding resistance Rc is applied to the non-inverting input terminal of the voltage buffer 14.
    A cathode of the diode D10 is connected to the output terminal of the voltage buffer 14, and an anode of the diode D10 is connected to an inverting input terminal of the voltage buffer 14 and to the connection point of the resistors RIO and R2. The voltage at the connection point of the resistors RIO and R2 is represented as a buffer output voltage Vcb2.
    The connection point of the resistor Rll and the thermistor Rth is connected to the non-inverting input terminal of the voltage buffer 18, and the voltage Vcc is applied to the other end of the resistor Rll. Thus, a voltage which is obtained by dividing the voltage Vcc by the resistor Rll and the thermistor Rth is applied to the non-inverting input terminal of the voltage buffer 18. A cathode of the diode DU is connected to the output terminal of the voltage buffer 18, and an anode of the diode DU is connected to an inverting input terminal of the voltage buffer 18 and to the connection point of the resistors RIO and R2.
    The thermistor Rth is a thermistor with a negative temperature coefficient (NTC), and its resistance value decreases as the temperature rises. Thus, as the temperature rises, the voltage at the non-inverting input terminal of the voltage buffer 18 decreases.
    [YES] The resistors RIO, R2 and R3 as well as the switch corresponding to functions 15 are connected in series between the voltage Vcc and the ground. The switch corresponding to functions 15 changes to the blocked state when the first function is determined by the function detector 12 and changes to the conductive state when the second function is determined by the function detector 12.
    The voltage at the connection point of the resistors R2 and R3 is supplied, as the dimming voltage Vdm, to the terminal 54 of the regulator 11.
    By means of this configuration, the buffer output voltage Vcb2 at the connection point of the resistors RIO and R12 goes to the lowest between the divided voltage of the resistance RI and of the coding resistance Rc and the divided voltage of resistance Rll and thermistor Rth. As a result, the buffer output voltage Vcb decreases at an elevated temperature, by means of a temperature dependent function, when adjustment by the coding resistor Rc is taken into account. In addition, because the buffer output voltage Vcb2 at the connection point of the resistors RIO and R2 is divided or not by the switch corresponding to functions 15, the dimming voltage Vdm during the first function and the second function becomes a voltage signal of the gradation ratio determined by resistors R2 and R3.
    Thus, while applying the dimming function for the purpose of temperature-based mismatching, it is possible to make the gradation ratio of the first function and of the second function not vary as a function of the coding resistance. Rc or temperature condition. <Fourth illustrative embodiment> A fourth illustrative embodiment is described below with reference to FIG. 9. In the fourth illustrative embodiment, a dimming voltage generator 20B of the emission control device light 2 is obtained by adding an inverter 16 and a derating control switch 17 to the dimming voltage generator 20A of FIG. 8.
    In other words, the derating control switch 17 is inserted between the thermistor Rth and the ground, and the function detector 12 controls the derating control switch 17 together with the switch corresponding to functions 15. More specifically, the function detector 12 reverses a gate voltage supplied to the switch corresponding to functions 15 by means of the inverter 16 and supplies the reverse gate voltage to the gate of the control switch. derating 17.
    In this case, during this first function, the switch corresponding to functions 15 goes to the blocked state and the mismatch control switch 17 goes to the conductive state. In addition, during the second function, the switch corresponding to functions 15 switches to the conductive state and the derating control switch 17 switches to the blocked state. Consequently, during the second function, the temperature-based mismatch is not carried out. More specifically, during the second function, the buffer output voltage Vcb2 does not vary as a function of the temperature.
    In other words, this configuration is an example which is used when the temperature-based mismatch is not executed during a function. <Summary and modifications> In each of the above illustrative embodiments, the light emission control device 2 comprises the DC / DC converter 10 which supplies the control current as the first current to the light emitting element (LED) 31 for causing the light emitting element 31 to emit light of the first function, and also supplies the control current as a second current which is less than the first current, the light emitting element, to cause the light emitting element to emit the light of the second function. In addition, the light emission control device 2 includes the dimming voltage generator 20 which applies a voltage obtained as a function of a resistance value of a coding resistor connected Rc, to the voltage buffer 14, and varies the output voltage Vcb of the voltage buffer 14 according to whether the light emitting element 31 has to produce a light emission from either of the first function and the second function, from so as to generate the dimming voltage Vdm, and the regulator 11 which regulates the control current Idr to the first current or to the second current, as a function of the dimming voltage Vdm. In other words, a dimming voltage value determined by the coding resistor Rc which is an external resistor is acquired by means of the voltage buffer 14, and its voltage is adjusted to the dimming voltage Vdm, depending on whether a light emission operation is the first function or the second function.
    The coding resistor Rc adjusts the control current as a function, for example, of the row of light fluxes. However, by means of a configuration in which a divided voltage determined by the resistance RI and the coding resistance Rc varies depending on whether it is the first function or the second function which is determined, the control current ratio (ratio of dimming) in the cases of the first function and the second function is modified by the coding resistor Rc. More specifically, the control current ratio is the ratio of the first current to the second current.
    It emerges from the comparison between the illustrative embodiment and the comparative example, that by transmitting a voltage determined by the coding resistor Rc, via the voltage buffer 14 which is a voltage follower with a gain of 1, and by varying the output voltage of the voltage buffer 14 during the first function and during the second function, it is possible to have a gradation ratio of the first function and the second function constant, regardless of the value of the coding resistance Rc.
    In addition, as soon as the dimming control is not carried out by the PWM signal, it is possible to prevent the degradation of the emission noise. In addition, no undesirable effects are produced due to the deterioration of the reproducibility of waveforms at a low duty cycle when the dimming control is carried out by the PWM signal.
    In the second illustrative embodiment, the regulator 11 can be controlled by the control current Idr, by means of the dimming signal by PWM SP, in addition to the dimming voltage Vdm, and the dimming signal by PWM SP is supplied to the regulator 11 when the light emitting element is made to emit the light of the second function.
    In other words, the dimming regulation is carried out by cooperation of a dimming (control current regulation) by means of the dimming voltage Vdm and a dimming (control current regulation) by means of the dimming signal by MLI SP.
    In this way, it is possible to obtain a higher gradation ratio, by combining a gradation by the gradation voltage Vdm and a gradation by the gradation signal by PWM SP.
    In the third and fourth illustrative embodiments, the dimming voltage generator 20A or 20B generates the dimming voltage Vdm which varies as a function of the resistance value of the thermistor Rth. In other words, the dimming voltage Vdm also functions as a control current regulating voltage for purposes of temperature-dependent derating.
    By this means it is possible to carry out both the regulation of the control current as a function of the decoding resistance Rc, the regulation of the control current for purposes of derating according to temperature and the regulation of the current control for the purposes of the first function and the second function, by means of the dimming voltage Vdm and to obtain an effective configuration.
    In the fourth illustrative embodiment, when the light emitting element is made to emit the light of the second function, the dimming voltage generator 20B prevents the dimming voltage Vdm from vary depending on the resistance value of a temperature sensor (thermistor Rth). In other words, the temperature derating is started during the first function, and the temperature derating is stopped during the second function.
    By this means it is possible to carry out a configuration in which the temperature-based derating control using the dimming voltage is switched on or off depending on the function. More precisely, depending on the function, it is possible to select an operation consisting in not performing dimming by temperature-dependent derating.
    In particular, in the case of the second function, as soon as the value of the control current Idr is low, that the protection of the light emitting element is not necessary and that, on the contrary, the brightness is a priority, it is possible to implement an operation consisting in not carrying out dimming by derating according to the temperature.
    In addition, FIGS. 8 and 9 illustrate an example of a circuit using both CC gradation and gradation by means of the dimming signal by MLI SP, as well as in the second illustrative embodiment of FIG. 7, but the configuration intended to carry out only the DC dimming as in FIG. 1 can adopt the dimming voltage generator 20A or 20B of FIGS. 8 and 9.
    The respective illustrative embodiments have described an example in which the first function is an emission of light as a daytime running light and the second function is an emission of light as a clearance light.
    It is further considered that the first function is an emission of light as a stop light and that the second function is an emission of light as a rear light. In other words, the present description is useful with regard to two functions consisting in carrying out light emission with a difference in quantity of light, using a common light emitting element.
    The present description is not limited to the configuration of the illustrative embodiment above, and various modifications are envisaged.
    In the illustrative embodiment, the light emitting element 31 performs the emission of light from two functions, but the description is not limited to the two functions, and the present description can also be applied to a case. where three or more functions use a common light source.
    For example, a configuration for switching the buffer output voltage depending on whether one or the other of the three functions is to be performed is envisaged. In addition, a specific configuration of the light emission control device 2, of the DC / DC converter 10, of the regulator 11 and of the dimming voltage generator 20 (20A and 20B) is not limited to the example above.
    From the above, it will be appreciated that various embodiments of the present description have been described here for illustrative purposes and that it is possible to make various modifications without departing from the scope and the spirit of the present description. Consequently, the various embodiments described here are not intended to be limiting, the real scope and spirit being indicated by the following claims.
    权利要求:
    Claims (6)
    [1" id="c-fr-0001]
    A light emission control device (2), comprising: a current supply unit (10), configured to supply a control current (Idr) as the first current to a light emitting element (31 ), so as to cause the light emitting element (31) to emit light of a first function, and to supply a control current (Idr) as a second current which is less than the first current, at the light emitting element (31), so as to cause the light emitting element to emit light of a second function; a dimming voltage generator (20, 20A, 20B) configured to apply a voltage, obtained as a function of a resistance value of an external resistance (Rc) connected, to a voltage buffer (14), and to make varying an output voltage of the voltage buffer (14) according to whether the light-emitting element (31) has to produce a light emission from either of the first function and the second function , so as to generate a dimming voltage; and a regulator (11) configured to regulate the control current to the first current or to the second current, depending on the dimming voltage.
    [2" id="c-fr-0002]
    2. light emission control device (2) according to claim 1, in which the regulator (11) is configured to regulate the control current by means of a dimming signal by modulation of pulse width also, in addition to the dimming voltage, and wherein the pulse width modulation dimming signal is supplied to the regulator (11), when the light emitting element (31) is made to perform the second function light emission.
    [3" id="c-fr-0003]
    3. Light emission control device (2) according to claim 1 or 2, wherein the dimming voltage generator (20, 20A, 20B) is configured to generate the dimming voltage which varies according to a resistance value of a temperature sensor.
    [4" id="c-fr-0004]
    The light emission control device (2) according to claim 3, wherein the dimming voltage generator (20, 20A, 20B) is configured to prevent the dimming voltage from varying according to the resistance value. of the temperature sensor, when it is arranged to cause the light emitting element (31) to emit light of the second function.
    [5" id="c-fr-0005]
    5. Light emission control device (2) according to any one of claims 1 to 4, wherein the first function is an emission of light as daytime running light and the second function is an emission of light in as a clearance light, or the first function is an emission of light as a stop lamp and the second function is an emission of light as a rear light.
    [6" id="c-fr-0006]
    6. Vehicle light (1) comprising: a light source device (3) comprising a light emitting element (31); and the light emission control device (2) according to any one of the preceding claims.
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    同族专利:
    公开号 | 公开日
    US20180343722A1|2018-11-29|
    CN108934108A|2018-12-04|
    FR3066875B1|2021-03-12|
    JP2018198174A|2018-12-13|
    US10470273B2|2019-11-05|
    CN108934108B|2021-03-30|
    JP6867228B2|2021-04-28|
    DE102018208177A1|2018-11-29|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JP4007096B2|2002-06-28|2007-11-14|松下電工株式会社|Lighting device|
    WO2008068682A1|2006-12-04|2008-06-12|Nxp B.V.|Electronic device for driving light emitting diodes|
    JP4799493B2|2007-06-29|2011-10-26|株式会社小糸製作所|Vehicle lighting|
    US7919928B2|2008-05-05|2011-04-05|Micrel, Inc.|Boost LED driver not using output capacitor and blocking diode|
    JP2010015752A|2008-07-02|2010-01-21|Koito Mfg Co Ltd|Lighting-up control device for vehicular lighting fixture|
    JP5301976B2|2008-12-11|2013-09-25|株式会社小糸製作所|Control device for vehicular lamp|
    JP5457684B2|2009-01-20|2014-04-02|株式会社小糸製作所|Lighting control device for vehicle lamp|
    JP5464204B2|2011-12-28|2014-04-09|株式会社デンソー|Light emission drive device|
    JP6440061B2|2014-07-15|2018-12-19|パナソニックＩｐマネジメント株式会社|Lighting device, lighting device, and vehicle headlamp device|
    US9880780B2|2015-11-30|2018-01-30|Samsung Electronics Co., Ltd.|Enhanced multi-stream operations|
    CN105430798A|2015-12-14|2016-03-23|山西省交通科学研究院|Daytime running outline marker lamp system of motor vehicle|
    CN205378269U|2016-01-04|2016-07-06|江苏中科朗恩斯车辆科技有限公司|LED head -light of can adjusting luminance based on constant current control|EP3672372A1|2018-12-21|2020-06-24|Valeo Vision|Method for maintaining luminosity when switching input power in automotive lighting devices|
    KR102108329B1|2019-09-23|2020-05-07|선텍|Power supply device for using a LED Light having function of converting power|
    法律状态:
    2020-04-14| PLFP| Fee payment|Year of fee payment: 3 |
    2020-07-10| PLSC| Publication of the preliminary search report|Effective date: 20200710 |
    2021-04-12| PLFP| Fee payment|Year of fee payment: 4 |
    优先权:
    申请号 | 申请日 | 专利标题
    JP2017102908A|JP6867228B2|2017-05-24|2017-05-24|Luminous drive, vehicle lighting|
    JP2017102908|2017-05-24|
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