WO2016194469A1 - Light-emitting element drive device, and switch drive device - Google Patents

Light-emitting element drive device, and switch drive device Download PDF

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Publication number
WO2016194469A1
WO2016194469A1 PCT/JP2016/061337 JP2016061337W WO2016194469A1 WO 2016194469 A1 WO2016194469 A1 WO 2016194469A1 JP 2016061337 W JP2016061337 W JP 2016061337W WO 2016194469 A1 WO2016194469 A1 WO 2016194469A1
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WIPO (PCT)
Prior art keywords
light
light emitting
rank
current
emitting element
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PCT/JP2016/061337
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French (fr)
Japanese (ja)
Inventor
登 瀧澤
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ローム株式会社
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Publication of WO2016194469A1 publication Critical patent/WO2016194469A1/en

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
    • H05B47/10—Controlling the light source
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
    • B60Q1/00—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
    • B60Q1/00—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor
    • B60Q1/02—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to illuminate the way ahead or to illuminate other areas of way or environments
    • B60Q1/04—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to illuminate the way ahead or to illuminate other areas of way or environments the devices being headlights
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
    • B60Q1/00—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor
    • B60Q1/26—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic
    • B60Q1/34—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic for indicating change of drive direction
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
    • B60Q1/00—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor
    • B60Q1/26—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic
    • B60Q1/44—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic for indicating braking action or preparation for braking, e.g. by detection of the foot approaching the brake pedal

Definitions

  • the present invention relates to a light emitting element driving device or a switch driving device.
  • Patent Document 1 and Patent Document 2 can be cited as examples of conventional techniques related to the above.
  • the simplest method for reducing the luminance variation of each light emitting element is to arrange all the light emitting elements with desired same rank products.
  • such conventional methods are disadvantageous in terms of distribution and cost, while facilitating the design of the light emitting device.
  • the invention disclosed in this specification is a light-emitting element driving device capable of causing a light-emitting element to emit light with a desired luminance, or a switch drive.
  • An object is to provide an apparatus.
  • a light-emitting element driving device disclosed in the present specification includes a driving unit that supplies a driving current to a light-emitting string formed by connecting a plurality of light-emitting components that incorporate a light-emitting element and a rank resistor in parallel;
  • the resistance values of the light emitting elements are individually read to detect the rank of each light emitting element, and the set value of the drive current is adjusted so that the light emitting element of the lowest rank emits light with a desired luminance, while for the other light emitting elements
  • a rank adjusting unit that bypasses the surplus drive current as a bypass current.
  • the switch driving device disclosed in the present specification includes a plurality of matrix switches connected in parallel to a plurality of light emitting components each incorporating a light emitting element and a rank resistor in parallel; and a resistance of each rank resistor The value is individually read to detect the rank of each light emitting element, and the setting value of the drive current supplied to the plurality of light emitting components is adjusted so that the light emitting element of the lowest rank emits light with a desired brightness,
  • the other light emitting elements are configured to have a rank adjusting unit that bypasses the surplus drive current as a bypass current.
  • a light emitting element driving device capable of causing a light emitting element to emit light with a desired luminance.
  • Block diagram showing an example of the overall configuration of a light emitting device Circuit diagram showing one configuration example of drive unit
  • the circuit diagram which shows 1st Embodiment of a rank adjustment part A circuit diagram showing a modification of the first embodiment
  • a block diagram showing a modification of the light emitting device The circuit diagram which shows 2nd Embodiment of a rank adjustment part Circuit diagram showing a third embodiment of the rank adjustment unit Circuit diagram showing a first modification of the light emitting device Circuit diagram showing a second modification of the light emitting device Circuit diagram showing a third modification of the light emitting device External view of the vehicle equipped with the light emitting device (front) External view of vehicle equipped with light emitting device (back) External view of LED headlight module External view of LED turn lamp module External view of LED rear lamp module
  • FIG. 1 is a block diagram illustrating an example of the overall configuration of the light emitting device 1.
  • the light emitting device 1 of this configuration example includes a light emitting element driving device 10, a light emitting string 20, and a sense resistor 30.
  • the light-emitting element driving device 10 is a semiconductor device (so-called LED [light emitting diode] driver IC) that drives the light-emitting string 20, and includes a driving unit 100 and a rank adjusting unit 200 integrated.
  • the light emitting element driving apparatus 10 includes external terminals T11 to T14 and external terminals T17a and T17b as means for establishing electrical connection with the outside of the apparatus.
  • the external terminal T11 is an input terminal for the input voltage Vin.
  • the external terminal T12 is an output terminal for the output voltage Vout.
  • the external terminal T13 is a feedback control terminal for the drive current Iout.
  • the external terminal T14 is a ground terminal connected to the ground.
  • the external terminal T17a is connected to the external terminal T21b of the light emitting component 21 and the external terminal T22a of the light emitting component 22, respectively.
  • the external terminal T17b is connected to the external terminal T22b of the light emitting component 22 and the external terminal T23a of the light emitting component 23, respectively.
  • the driving unit 100 generates the output voltage Vout from the input voltage Vin and supplies it to the light emitting string 20. At this time, the drive unit 100 performs negative feedback control (constant current control) so that the drive current Iout supplied to the light emitting string 20 becomes a target current value corresponding to the set value Dset.
  • the rank adjustment unit 200 individually reads the resistance values of the rank resistors R1 to R3 incorporated in the light emitting components 21 to 23, detects the ranks of the light emitting elements L1 to L3, and determines the lowest rank according to the detection result. While the set value Dset of the drive current Iout is adjusted so that the light emitting elements emit light with a desired luminance, the other light emitting elements have a function of bypassing the surplus drive current Iout as a bypass current.
  • the configuration and operation of the rank adjustment unit 200 will be described in detail later.
  • the light-emitting string 20 is a light-emitting component row formed by connecting light-emitting components 21 to 23 in series. Note that the number m of series stages of light-emitting components is not limited to three, but can be set to any number of series stages m (where m ⁇ 1) depending on the application.
  • the light emitting element L * for example, a light emitting diode element can be suitably used.
  • the rank resistance R * has a resistance value corresponding to the rank of the light emitting element L *.
  • FIG. 2 is a circuit diagram illustrating a configuration example of the drive unit 100.
  • the drive unit 100 of this configuration example is a linear regulator (a so-called LDO [low drop out] regulator) including an output transistor 101, a differential amplifier 102, a digital / analog conversion unit 103, and an operational amplifier 104.
  • LDO [low drop out] regulator a so-called LDO [low drop out] regulator
  • a voltage Vfb is generated.
  • the feedback voltage Vfb increases as the drive current Iout increases, and decreases as the drive current Iout decreases.
  • the digital / analog conversion unit 103 converts the digital set value Dset input from the rank adjustment unit 200 into an analog reference voltage Vref.
  • the reference voltage Vref increases as the set value Dset increases, and the reference voltage Vref decreases as the set value Dset decreases.
  • the reference voltage Vref is variably controlled according to the set value Dset.
  • the operational amplifier 104 controls the gate of the output transistor 101 so that the reference voltage Vref input to the non-inverting input terminal (+) matches the feedback voltage Vfb input to the inverting input terminal ( ⁇ ) (imaginary short). I do. With such a configuration, negative feedback control (constant current control) for maintaining the drive current Iout at the target current value corresponding to the set value Dset is realized.
  • the drive unit 100 is not limited to a linear regulator, and for example, a switching regulator that generates a desired output voltage Vout from the input voltage Vin by controlling the on-duty of the output transistor may be used.
  • FIG. 3 is a circuit diagram illustrating the first embodiment of the rank adjustment unit 200.
  • the rank adjustment unit 200 of the present embodiment includes a current source 251, a switch 252, current sources 254 (1) to (3), voltmeters 255 (1) to (3), and a control unit 256. .
  • the current source 251 is connected between the power supply end and the external terminal T13, and applies the first current I1 to the light emitting string 20.
  • the current value of the first current I1 is appropriately set in a range in which the voltage between both ends of each rank resistor R * does not become higher than the forward drop voltage Vf of each light emitting element L *.
  • the current value of the first current I1 may be set to less than 33 ⁇ A.
  • the switch 252 is connected between the current source 251 and the external terminal T13, and is turned on / off according to an instruction from the control unit 256.
  • the switch 252 is turned on only during the rank adjustment period of the light emitting element L *. Therefore, there is no possibility that the rank adjusting unit 200 adversely affects the normal lighting operation of the light emitting string 20.
  • the current source 254 (1) is connected between the external terminal T13 and the external terminal T17a.
  • the current source 254 (2) is connected between the external terminal T17a and the external terminal T17b.
  • the current source 254 (3) is connected between the external terminal T17b and the external terminal T14. That is, the current source 254 (*) is connected in parallel to the light emitting component 2 *, and according to an instruction from the control unit 256, when the light emitting string 20 is normally lit, the bypass current I4 for each light emitting component 2 *. While (*) is generated, the bypass current I4 (*) is set to 0A when the rank of the light emitting element L * is adjusted. Therefore, there is no possibility that the current source 254 (*) affects the rank adjustment operation of the light emitting element L *.
  • the rank adjustment unit 200 may include a switch 253 (*) that conducts / cuts off the current path of the bypass current I4 (*) in accordance with an instruction from the control unit 256.
  • the current source 254 (*) is turned on by turning on the switch 253 (*) when the light emitting string 20 is normally lit and turning off the switch 253 (*) when adjusting the rank of the light emitting element L *. Does not affect the rank adjustment operation of the light emitting element L *.
  • the voltmeter 255 (1) is connected between the external terminal T13 and the external terminal T17a.
  • the voltmeter 255 (2) is connected between the external terminal T17a and the external terminal T17b.
  • the voltmeter 255 (3) is connected between the external terminal T17b and the external terminal T14. That is, the voltmeter 255 (*) is connected in parallel to the light emitting component 2 *, and when the first current I1 is applied to the light emitting string 20, the voltmeter 255 (*) is connected between both ends of each rank resistor R *.
  • the first voltage V ⁇ b> 1 (*) that appears is measured, and the measurement result is output to the control unit 256.
  • FIG. 5 is a flowchart showing an example of the rank adjustment operation in the first embodiment. Note that the supply operation of the drive current Iout by the drive unit 100 is stopped while this flow is being executed.
  • step S41 the switch 252 is turned on to apply the first current I1 from the current source 251 to the light emitting string 20.
  • the first voltages V1 (1) to (3) are measured using the voltmeters 255 (1) to (3).
  • the voltage across the rank resistors R1 to R3 does not exceed the forward drop voltage Vf of the light emitting elements L1 to L3. That is, the first current I1 does not flow through the current path via the light emitting elements L1 to L3, but flows only through the current path via the rank resistors R1 to R3.
  • the rank resistors R1 to R3 have resistance values corresponding to the ranks of the light emitting elements L1 to L3, respectively. Accordingly, the ranks of the light emitting elements L1 to L3 can be detected by calculating the resistance values of the rank resistors R1 to R3, respectively.
  • the current value of the drive current Iout is calculated.
  • step S45 the control unit 256 appropriately sets the set value Dset of the drive current Iout according to the calculation result in step S44.
  • the control unit 256 adjusts the bypass currents I4 (1) to (3) in accordance with the resistance values of the rank resistors R1 to R3. For example, when the light emitting element L1 has the lowest rank, the current value of the drive current Iout is adjusted so that the light emitting element L1 emits light with a desired luminance. Therefore, since all the drive current Iout has only to flow through the light emitting element L1, the bypass current I4 (1) is set to a zero value. Note that the current path through which the bypass current I4 (1) flows may be blocked by turning off the switch 253 (1) in FIG.
  • the light emitting element L2 having a higher rank than the light emitting element L1
  • the drive current Iout may be set to 50 mA
  • the bypass currents I4 (1) to I4 (3) may be set to 0 mA, 5 mA, and 10 mA, respectively.
  • the rank adjusting unit 200 individually reads the resistance values of the rank resistors R1 to R3 to detect the ranks of the light emitting elements L1 to L3, and the light emitting element of the lowest rank has a desired luminance.
  • the set value Dset of the drive current Iout is adjusted so that light is emitted at the same time, while the other light emitting elements are configured to bypass the surplus drive current Iout as bypass currents I4 (1) to (3). .
  • the driving current Iout and the bypass currents I4 (1) to (3) are automatically optimized according to the ranks of the light emitting elements L1 to L3. 20 can be designed individually.
  • FIG. 6 is a block diagram illustrating a modification of the light emitting device 1.
  • the light emitting device 1 of this modification is provided with a switch driving device 40 and a microcomputer 50 in addition to the components (the light emitting element driving device 10, the light emitting string 20, and the sense resistor 30) of FIG. 5 is characterized in that the rank adjusting unit 200 described above is transferred from the light emitting element driving device 10 to the switch driving device 40. Therefore, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and redundant description is omitted.
  • characteristic portions of this modification will be mainly described.
  • the switch driving device 40 is a semiconductor device (so-called matrix switch driver IC) that switches between short-circuiting and non-short-circuiting of the light-emitting components 21 to 23 that form the light-emitting string 20, and includes matrix switches SW1 to SW3, a rank adjusting unit 200, including.
  • matrix switch driver IC semiconductor device that switches between short-circuiting and non-short-circuiting of the light-emitting components 21 to 23 that form the light-emitting string 20, and includes matrix switches SW1 to SW3, a rank adjusting unit 200, including.
  • the switch drive device 40 includes a plurality of external terminals T41 to T44 as means for establishing an electrical connection with the outside of the device.
  • the external terminal T41 of the switch driving device 40 is connected to the external terminal T21a of the light emitting component 21.
  • the external terminal T42 of the switch driving device 40 is connected to the external terminal T21b of the light emitting component 21 and the external terminal T22a of the light emitting component 22, respectively.
  • the external terminal T43 of the switch driving device 40 is connected to the external terminal T22b of the light emitting component 22 and the external terminal T23a of the light emitting component 23, respectively.
  • the external terminal T44 of the switch driving device 40 is connected to the external terminal T23b of the light emitting component 23.
  • the matrix switch SW1 is connected between the external terminal T41 and the external terminal T42.
  • the matrix switch SW2 is connected between the external terminal T42 and the external terminal T43.
  • the matrix switch SW3 is connected between the external terminal T43 and the external terminal T44.
  • P-channel MOS field effect transistors are used as the matrix switches SW1 to SW3.
  • the matrix switch SW * is connected in parallel to the light emitting component 2 *. Accordingly, when the matrix switch SW * is turned on, both ends of the light emitting component 2 * are short-circuited, so that the light emitting component 2 * cannot be turned on. On the other hand, when the matrix switch SW * is off, both ends of the light emitting component 2 * are not short-circuited, so that the light emitting component 2 * can be turned on.
  • the light emitting components 21 to 23 can be turned on and off at an arbitrary timing.
  • the lighting area is increased or decreased or moved so as to flow through the lighting area.
  • a lighting function (so-called sequential turn function or dynamic indicator function) can be realized.
  • the rank adjustment unit 200 is a circuit unit that reads the resistance values of the rank resistors R1 to R3, detects the ranks of the light emitting elements L1 to L3, and adjusts the set value Dset of the drive current Iout according to the detection result. .
  • the adjustment process for the set value Dset can be performed directly by the rank adjustment unit 200. However, as shown in the figure, the rank adjustment unit 200 notifies the microcomputer 50 of the rank detection result, and The microcomputer 50 may be configured to adjust the set value Dset according to the notification result.
  • the microcomputer 50 is a main body that controls the light emitting device 1 in an integrated manner.
  • the cooperative operation of the light emitting element driving device 10 and the switch driving device 40 is realized with the microcomputer 50 acting as an intermediary.
  • the rank detection processing of the light emitting elements L1 to L3 is performed using the switch driving device 20, and the adjustment processing of the set value Dset according to the detection result is performed using the microcomputer 50.
  • the division of roles has been established in which the light emitting element driving device 10 is used to generate the drive current Iout according to the set value Dset.
  • the switch driver 20 includes not only the external terminals T41 and T44 respectively connected to both end nodes of the light-emitting string 20 as external terminals for realizing the sequential lighting function of the light-emitting components 21 to 23, but also the light-emitting string 20.
  • FIG. 7 is a circuit diagram illustrating a second embodiment of the rank adjustment unit 200.
  • the rank adjustment unit 200 of the present embodiment includes a current source 261, a switch 262, current sources 264 (1) to (3), voltmeters 265 (1) to (3), and a control unit 266. .
  • the current source 261 is connected between the power supply terminal and the external terminal T41, and applies the first current I1 to the light emitting string 20.
  • the current value of the first current I1 is appropriately set within a range in which the voltage across the rank resistors R * does not become higher than the forward voltage drop Vf of each light emitting element L *.
  • the switch 262 is connected between the current source 261 and the external terminal T41, and is turned on / off according to an instruction from the control unit 266.
  • the switch 262 is turned on only during the rank adjustment period of the light emitting element L *. Therefore, there is no possibility that the rank adjusting unit 200 adversely affects the normal lighting operation of the light emitting string 20.
  • the current source 264 (1) is connected between the external terminal T41 and the external terminal T42.
  • the current source 264 (2) is connected between the external terminal T42 and the external terminal T43.
  • the current source 264 (3) is connected between the external terminal T43 and the external terminal T44. That is, the current source 264 (*) is connected in parallel to the light-emitting component 2 *, and when the light-emitting string 20 is normally lit according to an instruction from the control unit 266, a bypass current for each light-emitting component 2 *. While I4 (*) is generated, the bypass current I4 (*) is set to 0A when the rank of the light emitting element L * is adjusted. Therefore, there is no possibility that the current source 254 (*) affects the rank adjustment operation of the light emitting element L *.
  • the voltmeter 265 (1) is connected between the external terminal T41 and the external terminal T42.
  • the voltmeter 265 (2) is connected between the external terminal T42 and the external terminal T43.
  • the voltmeter 265 (3) is connected between the external terminal T43 and the external terminal T44. That is, the voltmeter 265 (*) is connected in parallel to the light emitting component 2 *, and when the first current I1 is applied to the light emitting string 20, the voltage meter 265 (*) is connected between both ends of each rank resistor R *.
  • the first voltage V ⁇ b> 1 (*) that appears is measured, and the measurement result is output to the control unit 266.
  • the microcomputer 50 adjusts the current value of the bypass current I4 (*)
  • the microcomputer 50 may notify the control unit 266 of the set value of the bypass current I4 (*).
  • the control unit 266 also has an on / off control function for the matrix switches SW1 to SW3. More specifically, the control unit 266 appropriately controls on / off of the matrix switches SW1 to SW3 when sequentially controlling the lighting of the light emitting components 21 to 23, while adjusting the ranks of the light emitting elements L1 to L3. Both are turned off. Therefore, there is no possibility that the matrix switch SW * adversely affects the rank adjustment operation of the light emitting element L *.
  • the rank adjustment unit 200 of the present embodiment basically detects the rank of the light emitting element L * by individually reading the resistance value of the rank resistance R * as in the first embodiment (see FIGS. 3 to 5). Then, the set value Dset of the drive current Iout is adjusted so that the light emitting element of the lowest rank emits light with a desired luminance, while the surplus of the drive current Iout is bypassed as a bypass current I4 (*) for the other light emitting elements. It is supposed to be configured.
  • the number of external terminals of the light emitting element driving device 10 can be reduced without detracting from the advantages of the fifth embodiment.
  • FIG. 8 is a circuit diagram illustrating a third embodiment of the rank adjustment unit 200.
  • the rank adjustment unit 200 of the present embodiment includes a current source 271, a switch 272, current sources 274 (1) to (3), voltmeters 275 (1) to (3), a control unit 276, and a P channel.
  • the current source 271 is connected between the power supply terminal and the external terminal T41, and applies the first current I1 to the light emitting string 20.
  • the current value of the first current I1 is appropriately set within a range in which the voltage across the rank resistors R * does not become higher than the forward voltage drop Vf of each light emitting element L *.
  • the switch 272 is connected between the current source 271 and the external terminal T41, and is turned on / off according to an instruction from the control unit 276.
  • the switch 272 is turned on only during the rank adjustment period of the light emitting element L *. Therefore, there is no possibility that the rank adjusting unit 200 adversely affects the normal lighting operation of the light emitting string 20.
  • Each of the current sources 274 (*) is connected between the drain of the transistor P * and the ground terminal, and in response to an instruction from the control unit 276, the bypass current I4 (*) for each light emitting component 2 * is set. Generate.
  • the voltmeter 275 (1) is connected between the external terminal T41 and the external terminal T42.
  • the voltmeter 275 (2) is connected between the external terminal T42 and the external terminal T43.
  • the voltmeter 275 (3) is connected between the external terminal T43 and the external terminal T44. That is, the voltmeter 275 (*) is connected in parallel to the light emitting component 2 *, and when the first current I1 is applied to the light emitting string 20, the voltage meter 275 (*) is connected between both ends of each rank resistor R *.
  • the first voltage V ⁇ b> 1 (*) that appears is measured, and the measurement result is output to the control unit 276.
  • the set value Dset of Iout and the current value of the bypass current I4 (*) are adjusted.
  • the microcomputer 50 adjusts the current value of the bypass current I4 (*)
  • the microcomputer 50 may notify the control unit 276 of the set value of the bypass current I4 (*).
  • the control unit 276 also has an on / off control function for the matrix switches SW1 to SW3. More specifically, the control unit 276 appropriately turns on / off the matrix switches SW1 to SW3 when sequentially controlling the lighting of the light emitting components 21 to 23, while adjusting the ranks of the light emitting elements L1 to L3. Both are turned off. Therefore, there is no possibility that the matrix switch SW * adversely affects the rank adjustment operation of the light emitting element L *.
  • the gate of the transistor P1 is connected to the drain of the transistor P1, the drain of the transistor P4, and the gate of the matrix switch SW1.
  • the source of the transistor P1 and the source of the transistor P4 are both connected to the external terminal T41.
  • the gate of the transistor P4 is connected to the control unit 276.
  • the gate of the transistor P2 is connected to the drain of the transistor P2, the drain of the transistor P5, and the gate of the matrix switch SW2.
  • the source of the transistor P2 and the source of the transistor P5 are both connected to the external terminal T42.
  • the gate of the transistor P5 is connected to the control unit 276.
  • the gate of the transistor P3 is connected to the drain of the transistor P3, the drain of the transistor P6, and the gate of the matrix switch SW3.
  • the source of the transistor P3 and the source of the transistor P6 are both connected to the external terminal T43.
  • the gate of the transistor P6 is connected to the control unit 276.
  • the transistors P1 to P3 are provided so as to form a pair with the matrix switches SW1 to SW3, respectively, and the bypass currents I4 (1) to (3) generated by the current sources 274 (1) to (3) are provided. 3) are mirrored to form current mirrors that flow into the matrix switches SW1 to SW3.
  • the rank adjustment unit 200 basically reads the resistance value of the rank resistance R * individually as in the first embodiment (FIGS. 3 to 5) and the second embodiment (FIG. 7). Each of the L * ranks is detected, and the set value Dset of the drive current Iout is adjusted so that the light emitting element of the lowest rank emits light with a desired luminance, while the surplus of the drive current Iout is bypassed for the other light emitting elements.
  • the current I4 (*) is bypassed.
  • the bypass current I4 (*) is bypassed by diverting the matrix switch SW * originally provided in the switch driving device 40.
  • the bypass current I4 ((4) is set so that the voltage across the rank resistor R1 does not become higher than the forward drop voltage Vf of the light emitting element L1 after the transistor P4 is turned off. 1) may be set to a current value comparable to the drive current Iout. The same applies to the case where the light-emitting component 22 or 23 is turned off.
  • the transistor P5 or P6 is turned off, and the bypass current I4 (2) or I4 (3) is set to the same current value as the drive current Iout. You only have to set it.
  • the matrix switch SW1 is completely turned on by turning on the transistor P4. Just turn it off.
  • the matrix switch SW2 or SW3 may be completely turned off by turning on the transistor P5 or P6.
  • FIG. 9 is a circuit diagram illustrating a first modification of the light emitting device.
  • the light emitting device 500 of this modification includes current sources 511 to 514, switches 521 to 524, light emitting components 531 to 534, and voltmeters 541 to 544.
  • the first ends of the current sources 511 to 514 are all connected to the power supply end. Second ends of the current sources 511 to 511 to 514 are connected to first ends of the switches 521 to 524, respectively. Second ends of the switches 521 to 524 are connected to anodes of the light emitting components 531 to 534, respectively. The cathodes of the light emitting components 531 to 534 are all connected to the ground terminal. Note that the light emitting components 531 to 534 include a light emitting element and a rank resistor in parallel. The voltmeters 541 to 544 are connected in parallel to the light emitting components 531 to 534, respectively.
  • the rank resistance values of the light emitting components 531 to 534 connected in parallel are also measured using the voltmeters 541 to 544, and the drive current values generated by the current sources 511 to 514 according to the measurement results. Can be set as appropriate.
  • FIG. 10 is a circuit diagram showing a second modification of the light emitting device.
  • the light emitting device 600 of this modification includes current sources 601 and 602, a switch 603, a light emitting component 604, and a voltmeter 605.
  • the first ends of the current sources 601 and 602 are both connected to the power supply end.
  • the second ends of the current sources 601 and 602 are connected to the first selection end and the second selection end of the switch 603, respectively.
  • the common end of the switch 603 is connected to the anode of the light emitting component 604.
  • the cathode of the light emitting component 604 is connected to the ground terminal.
  • the light emitting component 604 includes a light emitting element and a rank resistor in parallel.
  • the voltmeter 605 is connected to the light emitting component 604 in parallel.
  • the current source 601 that generates a variable current (for driving) according to the measurement result of the voltmeter 605 and the current source 602 that generates a fixed current (for rank detection) are provided in parallel, and the switch 603 is provided. It is good also as a structure which uses and switches both.
  • FIG. 11 is a circuit diagram showing a third modification of the light emitting device.
  • a light emitting device 700 according to this modification includes current sources 701 and 702, a switch 703, a light emitting component 704, and a voltmeter 705.
  • the first end of the current source 701 is connected to the power supply end.
  • the second end of the current source 701 is connected to the first end of the switch 703.
  • a second end of the switch 703 is connected to the anode of the light emitting component 704.
  • the cathode of the light emitting component 704 is connected to the ground terminal.
  • the light emitting component 704 includes a light emitting element and a rank resistor in parallel. Both the current source 702 and the voltmeter 705 are connected in parallel to the light emitting component 704.
  • a current source 702 that generates a variable current (for bypass) according to the measurement result of the voltmeter 705 is provided, which is a surplus for the light emitting component 704. It is good also as a structure which bypasses an electric current.
  • the light-emitting device 1 includes a headlight (including a high beam / low beam / small lamp / fog lamp, etc.) X11 of a vehicle X10, a light source X12 for day / night driving (DRL), a tail lamp (small). (Including lamps and back lamps as appropriate) X13, stop lamp X14, turn lamp X15, and the like.
  • the light emitting element driving device 10 is provided as a module (LED headlight module Y10 in FIG. 14, LED turn lamp module Y20 in FIG. 15, LED rear lamp module Y30 in FIG. 16, etc.) together with the light emitting string 20 to be driven. It may be provided, or may be provided as a single IC independently of the light-emitting string 20.
  • the configuration using a light emitting diode element as a light emitting element has been described as an example.
  • the configuration of the present invention is not limited to this, and for example, an organic EL as a light emitting element. It is also possible to use an [electro-luminescence] element.
  • the invention disclosed in the present specification can be used for, for example, an in-vehicle exterior lamp, an illumination lamp, and the like (particularly, a light emitting device whose luminance is strictly determined by law or the like).

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  • Circuit Arrangement For Electric Light Sources In General (AREA)
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Abstract

This light-emitting element drive device comprises: a drive unit supplying a drive current to a light-emitting string constituted by connecting in series a plurality of light-emitting components whereof each has a light-emitting element and a rank resistor integrated in parallel; and a rank adjusting unit reading the resistor value of each rank resistor individually to detect the rank of each light-emitting element respectively, and adjusting the setting value of the drive current in such a manner that the lowest rank light-emitting element emits light at a desired brightness, while, regarding the other light-emitting elements, diverting the excess portion of the drive current as a bypass current. This switch drive device comprises: a plurality of matrix switches connected in parallel respectively to a plurality of light-emitting components whereof each has a light-emitting element and a rank resistor integrated in parallel; and a rank adjusting unit reading the resistor value of each rank resistor individually to detect the rank of each light-emitting element respectively, and adjusting the setting value of the drive current supplied to the plurality of light-emitting components in such a manner that the lowest rank light-emitting element emits light at a desired brightness, while, regarding the other light-emitting elements, diverting the excess portion of the drive current as a bypass current.

Description

発光素子駆動装置、スイッチ駆動装置Light emitting element driving device, switch driving device
　本発明は、発光素子駆動装置、ないしは、スイッチ駆動装置に関する。 The present invention relates to a light emitting element driving device or a switch driving device.
　従来より、発光ダイオード素子や有機ＥＬ素子などの発光素子は、その輝度特性（＝所定の駆動電流を供給したときに得られる輝度の大きさ）に応じてランク分けされている。 Conventionally, light emitting elements such as light emitting diode elements and organic EL elements are ranked according to their luminance characteristics (= the magnitude of luminance obtained when a predetermined drive current is supplied).
　なお、上記に関連する従来技術の一例としては、特許文献１や特許文献２を挙げることができる。 In addition, Patent Document 1 and Patent Document 2 can be cited as examples of conventional techniques related to the above.
特開２０１１－２２９０６０号公報JP 2011-229060 A 特開２０１３－２２９１７１号公報JP 2013-229171 A
　ところで、複数の発光素子を同時駆動する必要のあるアプリケーションにおいて、各発光素子の輝度ばらつきを低減する最も単純な手法は、全ての発光素子を所望の同一ランク品で揃えることである。しかしながら、このような従来手法では、発光装置の設計が容易となる半面、物流面やコスト面で不利であった。 By the way, in an application in which a plurality of light emitting elements need to be driven simultaneously, the simplest method for reducing the luminance variation of each light emitting element is to arrange all the light emitting elements with desired same rank products. However, such conventional methods are disadvantageous in terms of distribution and cost, while facilitating the design of the light emitting device.
　また、別の手法として、全ての発光素子を同一ロット品で揃えることも考えられる。同一ロット品ならば、所望のランク品であるかどうかはさておき、各発光素子毎のランク不揃いが生じるおそれは小さい。従って、ロット毎に駆動電流設定用パラメータ（センス抵抗値など）を適宜調整してやれば、全ての発光素子を所望の輝度で均一に駆動することが可能となる。しかしながら、このような従来手法では、発光素子のロット毎にディスクリート部品の付け替えなどを行う必要があるので、作業ミスの増大を招くおそれがあった。 Also, as another method, it is possible to arrange all the light emitting elements in the same lot. In the case of the same lot product, aside from whether it is a desired rank product, there is little possibility that non-uniform rank will occur for each light emitting element. Accordingly, if the drive current setting parameters (such as the sense resistance value) are appropriately adjusted for each lot, it is possible to drive all the light emitting elements uniformly with a desired luminance. However, in such a conventional method, it is necessary to replace discrete components for each lot of light emitting elements, which may cause an increase in work errors.
　なお、単一の発光素子を駆動する場合であっても、これを所望の輝度で発光させるためには、発光素子として所望のランク品を用いるか、若しくは、発光素子のランクに応じて駆動電流設定用パラメータを手作業で調整しなければならなかった。 Even in the case of driving a single light emitting element, in order to emit light with a desired luminance, a desired rank product is used as the light emitting element, or a driving current according to the rank of the light emitting element. The setting parameters had to be adjusted manually.
　本明細書中に開示されている発明は、本願の発明者らにより見出された上記の問題点に鑑み、発光素子を所望の輝度で発光させることのできる発光素子駆動装置、ないしは、スイッチ駆動装置を提供することを目的とする。 In view of the above-mentioned problems found by the inventors of the present application, the invention disclosed in this specification is a light-emitting element driving device capable of causing a light-emitting element to emit light with a desired luminance, or a switch drive. An object is to provide an apparatus.
　本明細書中に開示されている発光素子駆動装置は、発光素子とランク抵抗を並列に内蔵した発光部品を複数直列に接続して成る発光ストリングに駆動電流を供給する駆動部と；各ランク抵抗の抵抗値を個別に読み取って各発光素子のランクをそれぞれ検出し、最低ランクの発光素子が所望の輝度で発光するように前記駆動電流の設定値を調整する一方、それ以外の発光素子については前記駆動電流の余剰分をバイパス電流として迂回させるランク調整部と；を有する構成とされている。 A light-emitting element driving device disclosed in the present specification includes a driving unit that supplies a driving current to a light-emitting string formed by connecting a plurality of light-emitting components that incorporate a light-emitting element and a rank resistor in parallel; The resistance values of the light emitting elements are individually read to detect the rank of each light emitting element, and the set value of the drive current is adjusted so that the light emitting element of the lowest rank emits light with a desired luminance, while for the other light emitting elements A rank adjusting unit that bypasses the surplus drive current as a bypass current.
　また、本明細書中に開示されているスイッチ駆動装置は、発光素子とランク抵抗を並列に内蔵した複数の発光部品に対してそれぞれ並列に接続された複数のマトリクススイッチと；各ランク抵抗の抵抗値を個別に読み取って各発光素子のランクをそれぞれ検出し、最低ランクの発光素子が所望の輝度で発光するように前記複数の発光部品に供給される駆動電流の設定値を調整する一方、それ以外の発光素子については前記駆動電流の余剰分をバイパス電流として迂回させるランク調整部と；を有する構成とされている。 In addition, the switch driving device disclosed in the present specification includes a plurality of matrix switches connected in parallel to a plurality of light emitting components each incorporating a light emitting element and a rank resistor in parallel; and a resistance of each rank resistor The value is individually read to detect the rank of each light emitting element, and the setting value of the drive current supplied to the plurality of light emitting components is adjusted so that the light emitting element of the lowest rank emits light with a desired brightness, The other light emitting elements are configured to have a rank adjusting unit that bypasses the surplus drive current as a bypass current.
　なお、本発明のその他の特徴、要素、ステップ、利点、及び、特性については、以下に続く実施形態の詳細な説明やこれに関する添付の図面によって、さらに明らかとなる。 Note that other features, elements, steps, advantages, and characteristics of the present invention will be further clarified by the detailed description of the embodiments that follow and the accompanying drawings.
　本明細書中に開示されている発明によれば、発光素子を所望の輝度で発光させることのできる発光素子駆動装置を提供することが可能となる。 According to the invention disclosed in the present specification, it is possible to provide a light emitting element driving device capable of causing a light emitting element to emit light with a desired luminance.
発光装置の全体構成例を示すブロック図Block diagram showing an example of the overall configuration of a light emitting device 駆動部の一構成例を示す回路図Circuit diagram showing one configuration example of drive unit ランク調整部の第１実施形態を示す回路図The circuit diagram which shows 1st Embodiment of a rank adjustment part 第１実施形態の一変形例を示す回路図A circuit diagram showing a modification of the first embodiment 第１実施形態におけるランク調整動作の一例を示すフローチャートThe flowchart which shows an example of the rank adjustment operation | movement in 1st Embodiment. 発光装置の一変形例を示すブロック図A block diagram showing a modification of the light emitting device ランク調整部の第２実施形態を示す回路図The circuit diagram which shows 2nd Embodiment of a rank adjustment part ランク調整部の第３実施形態を示す回路図Circuit diagram showing a third embodiment of the rank adjustment unit 発光装置の第１変形例を示す回路図Circuit diagram showing a first modification of the light emitting device 発光装置の第２変形例を示す回路図Circuit diagram showing a second modification of the light emitting device 発光装置の第３変形例を示す回路図Circuit diagram showing a third modification of the light emitting device 発光装置が搭載される車両の外観図（前面）External view of the vehicle equipped with the light emitting device (front) 発光装置が搭載される車両の外観図（背面）External view of vehicle equipped with light emitting device (back) ＬＥＤヘッドライトモジュールの外観図External view of LED headlight module ＬＥＤターンランプモジュールの外観図External view of LED turn lamp module ＬＥＤリアランプモジュールの外観図External view of LED rear lamp module
＜発光装置＞
　図１は、発光装置１の全体構成例を示すブロック図である。本構成例の発光装置１は、発光素子駆動装置１０と、発光ストリング２０と、センス抵抗３０と、を有する。 <Light emitting device>
FIG. 1 is a block diagram illustrating an example of the overall configuration of the light emitting device 1. The light emitting device 1 of this configuration example includes a light emitting element driving device 10, a light emitting string 20, and a sense resistor 30.
　発光素子駆動装置１０は、発光ストリング２０を駆動対象とする半導体装置（いわゆるＬＥＤ［light　emitting　diode］ドライバＩＣ）であり、駆動部１００と、ランク調整部２００と、を集積化して成る。 The light-emitting element driving device 10 is a semiconductor device (so-called LED [light emitting diode] driver IC) that drives the light-emitting string 20, and includes a driving unit 100 and a rank adjusting unit 200 integrated.
　また、発光素子駆動装置１０は、装置外部との電気的な接続を確立するための手段として、外部端子Ｔ１１～Ｔ１４と外部端子Ｔ１７ａ及びＴ１７ｂを備えている。外部端子Ｔ１１は、入力電圧Ｖｉｎの入力端子である。外部端子Ｔ１２は、出力電圧Ｖｏｕｔの出力端子である。外部端子Ｔ１３は、駆動電流Ｉｏｕｔの帰還制御端子である。外部端子Ｔ１４は、グランドに接続される接地端子である。外部端子Ｔ１７ａは、発光部品２１の外部端子Ｔ２１ｂと発光部品２２の外部端子Ｔ２２ａにそれぞれ接続されている。外部端子Ｔ１７ｂは、発光部品２２の外部端子Ｔ２２ｂと発光部品２３の外部端子Ｔ２３ａにそれぞれ接続されている。 Further, the light emitting element driving apparatus 10 includes external terminals T11 to T14 and external terminals T17a and T17b as means for establishing electrical connection with the outside of the apparatus. The external terminal T11 is an input terminal for the input voltage Vin. The external terminal T12 is an output terminal for the output voltage Vout. The external terminal T13 is a feedback control terminal for the drive current Iout. The external terminal T14 is a ground terminal connected to the ground. The external terminal T17a is connected to the external terminal T21b of the light emitting component 21 and the external terminal T22a of the light emitting component 22, respectively. The external terminal T17b is connected to the external terminal T22b of the light emitting component 22 and the external terminal T23a of the light emitting component 23, respectively.
　駆動部１００は、入力電圧Ｖｉｎから出力電圧Ｖｏｕｔを生成して発光ストリング２０に供給する。その際、駆動部１００は、発光ストリング２０に供給される駆動電流Ｉｏｕｔが設定値Ｄｓｅｔに応じた目標電流値となるように負帰還制御（定電流制御）を行う。 The driving unit 100 generates the output voltage Vout from the input voltage Vin and supplies it to the light emitting string 20. At this time, the drive unit 100 performs negative feedback control (constant current control) so that the drive current Iout supplied to the light emitting string 20 becomes a target current value corresponding to the set value Dset.
　ランク調整部２００は、発光部品２１～２３にそれぞれ内蔵されているランク抵抗Ｒ１～Ｒ３の抵抗値を個別に読み取って発光素子Ｌ１～Ｌ３のランクをそれぞれ検出し、その検出結果に応じて最低ランクの発光素子が所望の輝度で発光するように駆動電流Ｉｏｕｔの設定値Ｄｓｅｔを調整する一方、それ以外の発光素子については駆動電流Ｉｏｕｔの余剰分をバイパス電流として迂回させる機能を備えている。なお、ランク調整部２００の構成及び動作については、後ほど詳細に説明する。 The rank adjustment unit 200 individually reads the resistance values of the rank resistors R1 to R3 incorporated in the light emitting components 21 to 23, detects the ranks of the light emitting elements L1 to L3, and determines the lowest rank according to the detection result. While the set value Dset of the drive current Iout is adjusted so that the light emitting elements emit light with a desired luminance, the other light emitting elements have a function of bypassing the surplus drive current Iout as a bypass current. The configuration and operation of the rank adjustment unit 200 will be described in detail later.
　発光ストリング２０は、発光部品２１～２３を直列に接続して成る発光部品列である。なお、発光部品の直列段数ｍは３段に限るものではなく、その用途に応じて任意の直列段数ｍ（ただしｍ≧１）に設定することが可能である。 The light-emitting string 20 is a light-emitting component row formed by connecting light-emitting components 21 to 23 in series. Note that the number m of series stages of light-emitting components is not limited to three, but can be set to any number of series stages m (where m ≧ 1) depending on the application.
　発光部品２＊（ただし＊＝１、２、３、以下も同様）は、外部端子Ｔ２＊ａ及びＴ２＊ｂを備え、両外部端子間に発光素子Ｌ＊とランク抵抗Ｒ＊を並列に内蔵している。発光素子Ｌ＊としては、例えば、発光ダイオード素子を好適に用いることができる。ランク抵抗Ｒ＊は、発光素子Ｌ＊のランクに応じた抵抗値を持つ。 Light-emitting component 2 * (* = 1, 2, 3, and so on) includes external terminals T2 * a and T2 * b, and a light-emitting element L * and a rank resistor R * are incorporated in parallel between both external terminals. is doing. As the light emitting element L *, for example, a light emitting diode element can be suitably used. The rank resistance R * has a resistance value corresponding to the rank of the light emitting element L *.
　センス抵抗３０（抵抗値：Ｒｓ）は、駆動電流Ｉｏｕｔの流れる電流経路上に設けられており、駆動電流Ｉｏｕｔに応じたセンス電圧Ｖｓ（＝Ｉｏｕｔ×Ｒｓ）を生成する。 The sense resistor 30 (resistance value: Rs) is provided on a current path through which the drive current Iout flows, and generates a sense voltage Vs (= Iout × Rs) corresponding to the drive current Iout.
＜駆動部＞
　図２は、駆動部１００の一構成例を示す回路図である。本構成例の駆動部１００は、出力トランジスタ１０１と、差動アンプ１０２と、デジタル／アナログ変換部１０３と、オペアンプ１０４と、を含むリニアレギュレータ（いわゆるＬＤＯ［low　drop　out］レギュレータ）である。 <Driver>
FIG. 2 is a circuit diagram illustrating a configuration example of the drive unit 100. The drive unit 100 of this configuration example is a linear regulator (a so-called LDO [low drop out] regulator) including an output transistor 101, a differential amplifier 102, a digital / analog conversion unit 103, and an operational amplifier 104.
　出力トランジスタ１０１は、外部端子Ｔ１１（＝入力電圧Ｖｉｎの入力端）と外部端子Ｔ１２（＝出力電圧Ｖｏｕｔの出力端）との間に接続されており、オペアンプ１０４を用いてゲート駆動されるＰチャネル型ＭＯＳ［metal　oxide　semiconductor］電界効果トランジスタである。 The output transistor 101 is connected between the external terminal T11 (= input terminal of the input voltage Vin) and the external terminal T12 (= output terminal of the output voltage Vout), and is P-channel gate-driven using the operational amplifier 104. Type MOS [metal oxide semiconductor] field effect transistor.
　差動アンプ１０２の非反転入力端（＋）は、外部端子Ｔ１２（＝センス抵抗３０の高電位端）に接続されている。差動アンプ１０２の反転入力端（－）は、外部端子Ｔ１３（＝センス抵抗３０の低電位端）に接続されている。このように接続された差動アンプ１０２は、非反転入力端（＋）と反転入力端（－）との間に印加されるセンス電圧Ｖｓ（＝センス抵抗３０の両端間電圧）に応じた帰還電圧Ｖｆｂを生成する。帰還電圧Ｖｆｂは、駆動電流Ｉｏｕｔが大きいほど高くなり、駆動電流Ｉｏｕｔが小さいほど低くなる。 The non-inverting input terminal (+) of the differential amplifier 102 is connected to the external terminal T12 (= the high potential terminal of the sense resistor 30). The inverting input terminal (−) of the differential amplifier 102 is connected to the external terminal T13 (= the low potential terminal of the sense resistor 30). The differential amplifier 102 connected in this way is fed back according to the sense voltage Vs (= the voltage across the sense resistor 30) applied between the non-inverting input terminal (+) and the inverting input terminal (−). A voltage Vfb is generated. The feedback voltage Vfb increases as the drive current Iout increases, and decreases as the drive current Iout decreases.
　デジタル／アナログ変換部１０３は、ランク調整部２００から入力されるデジタルの設定値Ｄｓｅｔをアナログの基準電圧Ｖｒｅｆに変換する。例えば、設定値Ｄｓｅｔが大きいほど基準電圧Ｖｒｅｆが高くなり、設定値Ｄｓｅｔが小さいほど基準電圧Ｖｒｅｆが低くなる。このように、基準電圧Ｖｒｅｆは、設定値Ｄｓｅｔに応じて可変制御される。 The digital / analog conversion unit 103 converts the digital set value Dset input from the rank adjustment unit 200 into an analog reference voltage Vref. For example, the reference voltage Vref increases as the set value Dset increases, and the reference voltage Vref decreases as the set value Dset decreases. As described above, the reference voltage Vref is variably controlled according to the set value Dset.
　オペアンプ１０４は、非反転入力端（＋）に入力される基準電圧Ｖｒｅｆと、反転入力端（－）に入力される帰還電圧Ｖｆｂとが一致（イマジナリショート）するように、出力トランジスタ１０１のゲート制御を行う。このような構成とすることにより、駆動電流Ｉｏｕｔを設定値Ｄｓｅｔに応じた目標電流値に維持するための負帰還制御（定電流制御）が実現される。 The operational amplifier 104 controls the gate of the output transistor 101 so that the reference voltage Vref input to the non-inverting input terminal (+) matches the feedback voltage Vfb input to the inverting input terminal (−) (imaginary short). I do. With such a configuration, negative feedback control (constant current control) for maintaining the drive current Iout at the target current value corresponding to the set value Dset is realized.
　ただし、駆動部１００としては、リニアレギュレータに限らず、例えば、出力トランジスタのオンデューティを制御することにより入力電圧Ｖｉｎから所望の出力電圧Ｖｏｕｔを生成するスイッチングレギュレータを用いてもよい。 However, the drive unit 100 is not limited to a linear regulator, and for example, a switching regulator that generates a desired output voltage Vout from the input voltage Vin by controlling the on-duty of the output transistor may be used.
＜ランク調整部（第１実施形態）＞
　図３は、ランク調整部２００の第１実施形態を示す回路図である。本実施形態のランク調整部２００は、電流源２５１と、スイッチ２５２と、電流源２５４（１）～（３）と、電圧計２５５（１）～（３）と、制御部２５６と、を含む。 <Rank adjustment unit (first embodiment)>
FIG. 3 is a circuit diagram illustrating the first embodiment of the rank adjustment unit 200. The rank adjustment unit 200 of the present embodiment includes a current source 251, a switch 252, current sources 254 (1) to (3), voltmeters 255 (1) to (3), and a control unit 256. .
　電流源２５１は、電源端と外部端子Ｔ１３との間に接続されており、発光ストリング２０に第１電流Ｉ１を印加する。第１電流Ｉ１の電流値は、各ランク抵抗Ｒ＊の両端間電圧が各発光素子Ｌ＊の順方向降下電圧Ｖｆよりも高くならない範囲で適宜設定されている。例えば、ランク抵抗Ｒ＊の抵抗値が最高１００ｋΩであり、発光素子Ｌ＊の順方向降下電圧Ｖｆが３．３Ｖである場合、第１電流Ｉ１の電流値は３３μＡ未満に設定するとよい。 The current source 251 is connected between the power supply end and the external terminal T13, and applies the first current I1 to the light emitting string 20. The current value of the first current I1 is appropriately set in a range in which the voltage between both ends of each rank resistor R * does not become higher than the forward drop voltage Vf of each light emitting element L *. For example, when the rank resistance R * has a maximum resistance value of 100 kΩ and the forward drop voltage Vf of the light emitting element L * is 3.3 V, the current value of the first current I1 may be set to less than 33 μA.
　スイッチ２５２は、電流源２５１と外部端子Ｔ１３との間に接続されており、制御部２５６からの指示に応じてオン／オフされる。なお、スイッチ２５２は、発光素子Ｌ＊のランク調整期間にのみオンされる。従って、ランク調整部２００が発光ストリング２０の通常点灯動作に悪影響を及ぼすおそれはない。 The switch 252 is connected between the current source 251 and the external terminal T13, and is turned on / off according to an instruction from the control unit 256. The switch 252 is turned on only during the rank adjustment period of the light emitting element L *. Therefore, there is no possibility that the rank adjusting unit 200 adversely affects the normal lighting operation of the light emitting string 20.
　電流源２５４（１）は、外部端子Ｔ１３と外部端子Ｔ１７ａとの間に接続されている。電流源２５４（２）は、外部端子Ｔ１７ａと外部端子Ｔ１７ｂとの間に接続されている。電流源２５４（３）は、外部端子Ｔ１７ｂと外部端子Ｔ１４との間に接続されている。すなわち、電流源２５４（＊）は、発光部品２＊に対して並列に接続されており、制御部２５６からの指示に応じて、発光ストリング２０の通常点灯時には発光部品２＊毎のバイパス電流Ｉ４（＊）をそれぞれ生成する一方、発光素子Ｌ＊のランク調整時にはバイパス電流Ｉ４（＊）を０Ａとする。従って、電流源２５４（＊）が発光素子Ｌ＊のランク調整動作に影響を及ぼすおそれはない。 The current source 254 (1) is connected between the external terminal T13 and the external terminal T17a. The current source 254 (2) is connected between the external terminal T17a and the external terminal T17b. The current source 254 (3) is connected between the external terminal T17b and the external terminal T14. That is, the current source 254 (*) is connected in parallel to the light emitting component 2 *, and according to an instruction from the control unit 256, when the light emitting string 20 is normally lit, the bypass current I4 for each light emitting component 2 *. While (*) is generated, the bypass current I4 (*) is set to 0A when the rank of the light emitting element L * is adjusted. Therefore, there is no possibility that the current source 254 (*) affects the rank adjustment operation of the light emitting element L *.
　なお、ランク調整部２００は、図４で示すように、制御部２５６からの指示に応じてバイパス電流Ｉ４（＊）の電流経路を導通／遮断するスイッチ２５３（＊）を含む構成としてもよい。本構成を採用した場合には、発光ストリング２０の通常点灯時にスイッチ２５３（＊）をオンし、発光素子Ｌ＊のランク調整時にスイッチ２５３（＊）をオフすることにより、電流源２５４（＊）が発光素子Ｌ＊のランク調整動作に影響を及ぼさなくなる。 Note that, as shown in FIG. 4, the rank adjustment unit 200 may include a switch 253 (*) that conducts / cuts off the current path of the bypass current I4 (*) in accordance with an instruction from the control unit 256. When this configuration is adopted, the current source 254 (*) is turned on by turning on the switch 253 (*) when the light emitting string 20 is normally lit and turning off the switch 253 (*) when adjusting the rank of the light emitting element L *. Does not affect the rank adjustment operation of the light emitting element L *.
　電圧計２５５（１）は、外部端子Ｔ１３と外部端子Ｔ１７ａとの間に接続されている。電圧計２５５（２）は、外部端子Ｔ１７ａと外部端子Ｔ１７ｂとの間に接続されている。電圧計２５５（３）は、外部端子Ｔ１７ｂと外部端子Ｔ１４との間に接続されている。すなわち、電圧計２５５（＊）は、発光部品２＊に対して並列に接続されており、発光ストリング２０に対して第１電流Ｉ１が印加されているときに各ランク抵抗Ｒ＊の両端間に現れる第１電圧Ｖ１（＊）をそれぞれ測定し、その測定結果を制御部２５６に出力する。 The voltmeter 255 (1) is connected between the external terminal T13 and the external terminal T17a. The voltmeter 255 (2) is connected between the external terminal T17a and the external terminal T17b. The voltmeter 255 (3) is connected between the external terminal T17b and the external terminal T14. That is, the voltmeter 255 (*) is connected in parallel to the light emitting component 2 *, and when the first current I1 is applied to the light emitting string 20, the voltmeter 255 (*) is connected between both ends of each rank resistor R *. The first voltage V <b> 1 (*) that appears is measured, and the measurement result is output to the control unit 256.
　制御部２５６は、第１電流Ｉ１と第１電圧Ｖ１（＊）からランク抵抗Ｒ＊の抵抗値を算出し、その演算結果（＝発光素子Ｌ＊毎のランク検出結果）に応じて、駆動電流Ｉｏｕｔの設定値Ｄｓｅｔとバイパス電流Ｉ４（＊）の電流値をそれぞれ調整する。 The control unit 256 calculates the resistance value of the rank resistor R * from the first current I1 and the first voltage V1 (*), and according to the calculation result (= rank detection result for each light emitting element L *), the drive current The set value Dset of Iout and the current value of the bypass current I4 (*) are adjusted.
　以下では、制御部２５６によるランク調整動作について、フローチャートを参照しながら詳細に説明する。 Hereinafter, the rank adjustment operation by the control unit 256 will be described in detail with reference to a flowchart.
　図５は、第１実施形態におけるランク調整動作の一例を示すフローチャートである。なお、本フローが実行されている間、駆動部１００による駆動電流Ｉｏｕｔの供給動作は停止されているものとする。 FIG. 5 is a flowchart showing an example of the rank adjustment operation in the first embodiment. Note that the supply operation of the drive current Iout by the drive unit 100 is stopped while this flow is being executed.
　本フローが開始されると、まず、ステップＳ４１では、スイッチ２５２をオンすることにより、電流源２５１から発光ストリング２０に対して第１電流Ｉ１の印加が行われる。 When this flow is started, first, in step S41, the switch 252 is turned on to apply the first current I1 from the current source 251 to the light emitting string 20.
　続くステップＳ４２では、電圧計２５５（１）～（３）を用いて第１電圧Ｖ１（１）～（３）それぞれの測定が行われる。先にも述べたように、第１電流Ｉ１を印加しても各ランク抵抗Ｒ１～Ｒ３の両端間電圧が各発光素子Ｌ１～Ｌ３の順方向降下電圧Ｖｆを上回ることはない。すなわち、第１電流Ｉ１は、発光素子Ｌ１～Ｌ３を介する電流経路には流れず、ランク抵抗Ｒ１～Ｒ３を介する電流経路にのみ流れる。従って、第１電圧Ｖ１（１）～（３）は、それぞれランク抵抗Ｒ１～Ｒ３の抵抗値に第１電流Ｉ１を乗じた電圧値（＝Ｒ＊×Ｉ１）となる。なお、第１電圧Ｖ１（１）～（３）の測定は、同時並列的に実施してもよいし、順次時分割的に実施してもよい。 In subsequent step S42, the first voltages V1 (1) to (3) are measured using the voltmeters 255 (1) to (3). As described above, even if the first current I1 is applied, the voltage across the rank resistors R1 to R3 does not exceed the forward drop voltage Vf of the light emitting elements L1 to L3. That is, the first current I1 does not flow through the current path via the light emitting elements L1 to L3, but flows only through the current path via the rank resistors R1 to R3. Accordingly, the first voltages V1 (1) to (3) have voltage values (= R * × I1) obtained by multiplying the resistance values of the rank resistors R1 to R3 by the first current I1, respectively. Note that the measurement of the first voltages V1 (1) to (3) may be performed simultaneously in parallel or sequentially in a time-division manner.
　続くステップＳ４３では、制御部２５６により、第１電流Ｉ１と第１電圧Ｖ１（１）～（３）から、ランク抵抗Ｒ１～Ｒ３の抵抗値（＝Ｖ１（＊）／Ｉ１）がそれぞれ算出される。なお、ランク抵抗Ｒ１～Ｒ３は、それぞれ発光素子Ｌ１～Ｌ３のランクに応じた抵抗値を持っている。従って、ランク抵抗Ｒ１～Ｒ３の抵抗値を算出することにより、発光素子Ｌ１～Ｌ３のランクをそれぞれ検出することができる。 In subsequent step S43, the control unit 256 calculates the resistance values (= V1 (*) / I1) of the rank resistors R1 to R3 from the first current I1 and the first voltages V1 (1) to (3), respectively. . The rank resistors R1 to R3 have resistance values corresponding to the ranks of the light emitting elements L1 to L3, respectively. Accordingly, the ranks of the light emitting elements L1 to L3 can be detected by calculating the resistance values of the rank resistors R1 to R3, respectively.
　続くステップＳ４４では、制御部２５６により、ランク抵抗Ｒ１～Ｒ３の各抵抗値から最低ランクの発光素子（＝最も低輝度の発光素子）が判別され、これを所望の輝度で発光させるために必要な駆動電流Ｉｏｕｔの電流値が算出される。 In the subsequent step S44, the control unit 256 determines the light emitting element with the lowest rank (= the light emitting element with the lowest luminance) from the resistance values of the rank resistors R1 to R3, and is necessary for emitting the light with the desired luminance. The current value of the drive current Iout is calculated.
　続くステップＳ４５では、制御部２５６により、駆動電流Ｉｏｕｔの設定値ＤｓｅｔがステップＳ４４での算出結果に応じて適宜設定される。 In subsequent step S45, the control unit 256 appropriately sets the set value Dset of the drive current Iout according to the calculation result in step S44.
　続くステップＳ４６では、制御部２５６により、ランク抵抗Ｒ１～Ｒ３の抵抗値に応じたバイパス電流Ｉ４（１）～（３）の調整が行われる。例えば、発光素子Ｌ１が最低ランクである場合、駆動電流Ｉｏｕｔの電流値は、発光素子Ｌ１が所望の輝度で発光するように調整されている。従って、発光素子Ｌ１には、駆動電流Ｉｏｕｔを余すことなく全て流せばよいので、バイパス電流Ｉ４（１）がゼロ値に設定される。なお、図４のスイッチ２５３（１）をオフすることにより、バイパス電流Ｉ４（１）の流れる電流経路を遮断するようにしてもよい。 In subsequent step S46, the control unit 256 adjusts the bypass currents I4 (1) to (3) in accordance with the resistance values of the rank resistors R1 to R3. For example, when the light emitting element L1 has the lowest rank, the current value of the drive current Iout is adjusted so that the light emitting element L1 emits light with a desired luminance. Therefore, since all the drive current Iout has only to flow through the light emitting element L1, the bypass current I4 (1) is set to a zero value. Note that the current path through which the bypass current I4 (1) flows may be blocked by turning off the switch 253 (1) in FIG.
　一方、発光素子Ｌ１よりも高ランクの発光素子Ｌ２については、駆動電流Ｉｏｕｔをそのまま流すと、その輝度が高くなり過ぎる。そこで、駆動電流Ｉｏｕｔからバイパス電流Ｉ４（２）を差し引いた差分電流（＝Ｉｏｕｔ－Ｉ４（２））を発光素子Ｌ２に流すことにより、発光素子Ｌ２を所望の輝度で発光させることが可能となる。 On the other hand, for the light emitting element L2 having a higher rank than the light emitting element L1, if the drive current Iout is passed as it is, the luminance becomes too high. Therefore, by causing a differential current (= Iout−I4 (2)) obtained by subtracting the bypass current I4 (2) from the drive current Iout to flow through the light emitting element L2, the light emitting element L2 can emit light with a desired luminance. .
　また、発光素子Ｌ３についても、上記と同様であり、駆動電流Ｉｏｕｔからバイパス電流Ｉ４（３）を差し引いた差分電流（＝Ｉｏｕｔ－Ｉ４（３））を発光素子Ｌ３に流すことにより、発光素子Ｌ３を所望の輝度で発光させることが可能となる。 The light emitting element L3 is the same as described above, and a difference current (= Iout−I4 (3)) obtained by subtracting the bypass current I4 (3) from the drive current Iout is caused to flow through the light emitting element L3. Can be emitted with a desired luminance.
　例えば、発光素子Ｌ１～Ｌ３を所望の輝度で発光させるための必要電流値がそれぞれ５０ｍＡ、４５ｍＡ、４０ｍＡである場合を考える。この場合、駆動電流Ｉｏｕｔを５０ｍＡに設定し、バイパス電流Ｉ４（１）～Ｉ４（３）をそれぞれ０ｍＡ、５ｍＡ、１０ｍＡに設定すればよい。このような電流設定により、発光素子Ｌ１～Ｌ３のランクが不揃いであっても、発光ストリング２０全体を所望の輝度で均一に発光させることが可能となる。 For example, let us consider a case where the current values required for causing the light emitting elements L1 to L3 to emit light with a desired luminance are 50 mA, 45 mA, and 40 mA, respectively. In this case, the drive current Iout may be set to 50 mA, and the bypass currents I4 (1) to I4 (3) may be set to 0 mA, 5 mA, and 10 mA, respectively. With such current setting, even if the ranks of the light emitting elements L1 to L3 are not uniform, the entire light emitting string 20 can be uniformly emitted with a desired luminance.
　なお、発光部品２＊を迂回して流れるバイパス電流Ｉ４（＊）は、発光部品２＊に流れる差分電流（＝Ｉｏｕｔ－Ｉ４（＊））と足し合わされて下流側に流れる。すなわち、上流側の発光部品から下流側の発光部品に流れる電流は、見掛け上、駆動電流Ｉｏｕｔと同一の電流値に維持されている。従って、上流側の発光部品でバイパス電流Ｉ４（＊）を迂回させても、下流側の発光部品に必要な駆動電流Ｉｏｕｔが足りなくなることはない。 Note that the bypass current I4 (*) that flows around the light emitting component 2 * is added to the differential current (= Iout−I4 (*)) that flows through the light emitting component 2 * and flows downstream. That is, the current flowing from the upstream light emitting component to the downstream light emitting component is apparently maintained at the same current value as the drive current Iout. Therefore, even if the bypass current I4 (*) is bypassed by the light emitting component on the upstream side, the drive current Iout necessary for the light emitting component on the downstream side does not become insufficient.
　上記したように、第１実施形態のランク調整部２００は、ランク抵抗Ｒ１～Ｒ３の抵抗値を個別に読み取って発光素子Ｌ１～Ｌ３のランクをそれぞれ検出し、最低ランクの発光素子が所望の輝度で発光するように駆動電流Ｉｏｕｔの設定値Ｄｓｅｔを調整する一方、それ以外の発光素子については、駆動電流Ｉｏｕｔの余剰分をバイパス電流Ｉ４（１）～（３）として迂回させる構成とされている。 As described above, the rank adjusting unit 200 according to the first embodiment individually reads the resistance values of the rank resistors R1 to R3 to detect the ranks of the light emitting elements L1 to L3, and the light emitting element of the lowest rank has a desired luminance. The set value Dset of the drive current Iout is adjusted so that light is emitted at the same time, while the other light emitting elements are configured to bypass the surplus drive current Iout as bypass currents I4 (1) to (3). .
　このような構成であれば、発光素子Ｌ１～Ｌ３のランクに応じて駆動電流Ｉｏｕｔやバイパス電流Ｉ４（１）～（３）が自動的に最適化されるので、発光素子駆動装置１０と発光ストリング２０とを個別に設計することができる。 With such a configuration, the driving current Iout and the bypass currents I4 (1) to (3) are automatically optimized according to the ranks of the light emitting elements L1 to L3. 20 can be designed individually.
　また、本構成を採用することにより、発光部品２１～２３として、所望の同一ランク品を揃える必要がないばかりか、ロット毎の管理すら不要となる。従って、物流面やコスト面で有利となる。また、例えば、発光部品２１～２３のいずれかに不具合が生じた場合であっても、発光ストリング２０をまるごと交換する必要はなく、故障した発光部品を１個単位で交換することが可能となる。 In addition, by adopting this configuration, it is not necessary to arrange the desired same rank products as the light emitting components 21 to 23, and it becomes unnecessary to manage each lot. Therefore, it is advantageous in terms of physical distribution and cost. Further, for example, even when any of the light emitting components 21 to 23 is defective, it is not necessary to replace the entire light emitting string 20, and the failed light emitting component can be replaced in units of one. .
＜発光装置（一変形例）＞
　図６は、発光装置１の一変形例を示すブロック図である。本変形例の発光装置１は、図１の構成要素（発光素子駆動装置１０、発光ストリング２０、及び、センス抵抗３０）に加えてスイッチ駆動装置４０とマイコン５０が設けられており、かつ、先に説明したランク調整部２００が発光素子駆動装置１０からスイッチ駆動装置４０に移譲されている点に特徴を有する。そこで、図１と同様の構成要素については、図１と同一の符号を付すことで重複した説明を割愛し、以下では、本変形例の特徴部分について重点的に説明する。 <Light-emitting device (one modification)>
FIG. 6 is a block diagram illustrating a modification of the light emitting device 1. The light emitting device 1 of this modification is provided with a switch driving device 40 and a microcomputer 50 in addition to the components (the light emitting element driving device 10, the light emitting string 20, and the sense resistor 30) of FIG. 5 is characterized in that the rank adjusting unit 200 described above is transferred from the light emitting element driving device 10 to the switch driving device 40. Therefore, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and redundant description is omitted. Hereinafter, characteristic portions of this modification will be mainly described.
　スイッチ駆動装置４０は、発光ストリング２０を形成する発光部品２１～２３の短絡／非短絡をそれぞれ切り替える半導体装置（いわゆるマトリクススイッチドライバＩＣ）であり、マトリクススイッチＳＷ１～ＳＷ３と、ランク調整部２００と、を含む。 The switch driving device 40 is a semiconductor device (so-called matrix switch driver IC) that switches between short-circuiting and non-short-circuiting of the light-emitting components 21 to 23 that form the light-emitting string 20, and includes matrix switches SW1 to SW3, a rank adjusting unit 200, including.
　また、スイッチ駆動装置４０は、装置外部との電気的な接続を確立するための手段として、複数の外部端子Ｔ４１～Ｔ４４を備えている。スイッチ駆動装置４０の外部端子Ｔ４１は、発光部品２１の外部端子Ｔ２１ａに接続されている。スイッチ駆動装置４０の外部端子Ｔ４２は、発光部品２１の外部端子Ｔ２１ｂと発光部品２２の外部端子Ｔ２２ａにそれぞれ接続されている。スイッチ駆動装置４０の外部端子Ｔ４３は、発光部品２２の外部端子Ｔ２２ｂと発光部品２３の外部端子Ｔ２３ａにそれぞれ接続されている。スイッチ駆動装置４０の外部端子Ｔ４４は、発光部品２３の外部端子Ｔ２３ｂに接続されている。 Further, the switch drive device 40 includes a plurality of external terminals T41 to T44 as means for establishing an electrical connection with the outside of the device. The external terminal T41 of the switch driving device 40 is connected to the external terminal T21a of the light emitting component 21. The external terminal T42 of the switch driving device 40 is connected to the external terminal T21b of the light emitting component 21 and the external terminal T22a of the light emitting component 22, respectively. The external terminal T43 of the switch driving device 40 is connected to the external terminal T22b of the light emitting component 22 and the external terminal T23a of the light emitting component 23, respectively. The external terminal T44 of the switch driving device 40 is connected to the external terminal T23b of the light emitting component 23.
　マトリクススイッチＳＷ１は、外部端子Ｔ４１と外部端子Ｔ４２との間に接続されている。また、マトリクススイッチＳＷ２は、外部端子Ｔ４２と外部端子Ｔ４３との間に接続されている。また、マトリクススイッチＳＷ３は、外部端子Ｔ４３と外部端子Ｔ４４との間に接続されている。なお、本図の例では、マトリクススイッチＳＷ１～ＳＷ３として、いずれも、Ｐチャネル型ＭＯＳ電界効果トランジスタが用いられている。 The matrix switch SW1 is connected between the external terminal T41 and the external terminal T42. The matrix switch SW2 is connected between the external terminal T42 and the external terminal T43. The matrix switch SW3 is connected between the external terminal T43 and the external terminal T44. In the example of this figure, P-channel MOS field effect transistors are used as the matrix switches SW1 to SW3.
　すなわち、マトリクススイッチＳＷ＊は、発光部品２＊に対して並列接続されている。従って、マトリクススイッチＳＷ＊がオンされているときには、発光部品２＊の両端間が短絡されるので、発光部品２＊が点灯不能状態となる。一方、マトリクススイッチＳＷ＊がオフされているときには、発光部品２＊の両端間が非短絡とされるので、発光部品２＊が点灯可能状態となる。 That is, the matrix switch SW * is connected in parallel to the light emitting component 2 *. Accordingly, when the matrix switch SW * is turned on, both ends of the light emitting component 2 * are short-circuited, so that the light emitting component 2 * cannot be turned on. On the other hand, when the matrix switch SW * is off, both ends of the light emitting component 2 * are not short-circuited, so that the light emitting component 2 * can be turned on.
　このようなスイッチ制御を行うことにより、発光部品２１～２３を任意のタイミングで点消灯させることができるので、例えば、点灯領域の面積を増減させたり、点灯領域を流れるように移動させたりする順次点灯機能（いわゆる、シーケンシャルターン機能、ないしは、ダイナミックインジケータ機能）を実現することが可能となる。 By performing such switch control, the light emitting components 21 to 23 can be turned on and off at an arbitrary timing. For example, the lighting area is increased or decreased or moved so as to flow through the lighting area. A lighting function (so-called sequential turn function or dynamic indicator function) can be realized.
　ランク調整部２００は、ランク抵抗Ｒ１～Ｒ３の各抵抗値を読み取って発光素子Ｌ１～Ｌ３のランクをそれぞれ検出し、その検出結果に応じて駆動電流Ｉｏｕｔの設定値Ｄｓｅｔを調整する回路部である。なお、設定値Ｄｓｅｔの調整処理については、ランク調整部２００で直接実施することもできるが、本図で示したように、ランク調整部２００からマイコン５０に対してランク検出結果を通知し、その通知結果に応じてマイコン５０で設定値Ｄｓｅｔの調整処理を実施するようにしてもよい。 The rank adjustment unit 200 is a circuit unit that reads the resistance values of the rank resistors R1 to R3, detects the ranks of the light emitting elements L1 to L3, and adjusts the set value Dset of the drive current Iout according to the detection result. . The adjustment process for the set value Dset can be performed directly by the rank adjustment unit 200. However, as shown in the figure, the rank adjustment unit 200 notifies the microcomputer 50 of the rank detection result, and The microcomputer 50 may be configured to adjust the set value Dset according to the notification result.
　マイコン５０は、発光装置１を統括的に制御する主体である。特に、本変形例の発光装置１では、マイコン５０を仲介役とする形で、発光素子駆動装置１０とスイッチ駆動装置４０との連携動作が実現されている。 The microcomputer 50 is a main body that controls the light emitting device 1 in an integrated manner. In particular, in the light emitting device 1 of this modification, the cooperative operation of the light emitting element driving device 10 and the switch driving device 40 is realized with the microcomputer 50 acting as an intermediary.
　このように、本変形例の発光装置１では、スイッチ駆動装置２０を用いて発光素子Ｌ１～Ｌ３のランク検出処理を行い、マイコン５０を用いて検出結果に応じた設定値Ｄｓｅｔの調整処理を行い、発光素子駆動装置１０を用いて設定値Ｄｓｅｔに応じた駆動電流Ｉｏｕｔの生成処理を行う、という役割分担が確立されている。 Thus, in the light emitting device 1 of this modification, the rank detection processing of the light emitting elements L1 to L3 is performed using the switch driving device 20, and the adjustment processing of the set value Dset according to the detection result is performed using the microcomputer 50. Thus, the division of roles has been established in which the light emitting element driving device 10 is used to generate the drive current Iout according to the set value Dset.
　特に、スイッチ駆動装置２０には、発光部品２１～２３の順次点灯機能を実現するための外部端子として、発光ストリング２０の両端ノードにそれぞれ接続される外部端子Ｔ４１及びＴ４４だけでなく、発光ストリング２０の中間ノードにそれぞれ接続される外部端子Ｔ４２及びＴ４３が当初から設けられている。従って、例えば、先に説明した第１実施形態（＝ランク抵抗Ｒ１～Ｒ３の抵抗値をそれぞれ個別に検出する構成）のランク調整部２００を実装する場合であっても、発光素子駆動装置１０への実装時とは異なり、ランク調整専用の外部端子を別途増設する必要がないので、外部端子数削減の面で有利となる。 In particular, the switch driver 20 includes not only the external terminals T41 and T44 respectively connected to both end nodes of the light-emitting string 20 as external terminals for realizing the sequential lighting function of the light-emitting components 21 to 23, but also the light-emitting string 20. External terminals T42 and T43 respectively connected to the intermediate nodes are provided from the beginning. Therefore, for example, even when the rank adjusting unit 200 of the first embodiment described above (= the configuration in which the resistance values of the rank resistors R1 to R3 are individually detected) is mounted, the light emitting element driving device 10 is mounted. Unlike mounting, there is no need to add a separate external terminal for rank adjustment, which is advantageous in terms of reducing the number of external terminals.
＜ランク調整部（第２実施形態）＞
　図７は、ランク調整部２００の第２実施形態を示す回路図である。本実施形態のランク調整部２００は、電流源２６１と、スイッチ２６２と、電流源２６４（１）～（３）と、電圧計２６５（１）～（３）と、制御部２６６と、を含む。 <Rank adjustment unit (second embodiment)>
FIG. 7 is a circuit diagram illustrating a second embodiment of the rank adjustment unit 200. The rank adjustment unit 200 of the present embodiment includes a current source 261, a switch 262, current sources 264 (1) to (3), voltmeters 265 (1) to (3), and a control unit 266. .
　電流源２６１は、電源端と外部端子Ｔ４１との間に接続されており、発光ストリング２０に第１電流Ｉ１を印加する。第１電流Ｉ１の電流値は、先にも述べたように、各ランク抵抗Ｒ＊の両端間電圧が各発光素子Ｌ＊の順方向降下電圧Ｖｆよりも高くならない範囲で適宜設定されている。 The current source 261 is connected between the power supply terminal and the external terminal T41, and applies the first current I1 to the light emitting string 20. As described above, the current value of the first current I1 is appropriately set within a range in which the voltage across the rank resistors R * does not become higher than the forward voltage drop Vf of each light emitting element L *.
　スイッチ２６２は、電流源２６１と外部端子Ｔ４１との間に接続されており、制御部２６６からの指示に応じてオン／オフされる。なお、スイッチ２６２は、発光素子Ｌ＊のランク調整期間にのみオンされる。従って、ランク調整部２００が発光ストリング２０の通常点灯動作に悪影響を及ぼすおそれはない。 The switch 262 is connected between the current source 261 and the external terminal T41, and is turned on / off according to an instruction from the control unit 266. The switch 262 is turned on only during the rank adjustment period of the light emitting element L *. Therefore, there is no possibility that the rank adjusting unit 200 adversely affects the normal lighting operation of the light emitting string 20.
　電流源２６４（１）は、外部端子Ｔ４１と外部端子Ｔ４２との間に接続されている。電流源２６４（２）は、外部端子Ｔ４２と外部端子Ｔ４３との間に接続されている。電流源２６４（３）は、外部端子Ｔ４３と外部端子Ｔ４４との間に接続されている。すなわち、電流源２６４（＊）は、発光部品２＊に対して並列に接続されており、制御部２６６からの指示に応じて、発光ストリング２０の通常点灯時には、発光部品２＊毎のバイパス電流Ｉ４（＊）をそれぞれ生成する一方、発光素子Ｌ＊のランク調整時には、バイパス電流Ｉ４（＊）を０Ａとする。従って、電流源２５４（＊）が発光素子Ｌ＊のランク調整動作に影響を及ぼすおそれはない。 The current source 264 (1) is connected between the external terminal T41 and the external terminal T42. The current source 264 (2) is connected between the external terminal T42 and the external terminal T43. The current source 264 (3) is connected between the external terminal T43 and the external terminal T44. That is, the current source 264 (*) is connected in parallel to the light-emitting component 2 *, and when the light-emitting string 20 is normally lit according to an instruction from the control unit 266, a bypass current for each light-emitting component 2 *. While I4 (*) is generated, the bypass current I4 (*) is set to 0A when the rank of the light emitting element L * is adjusted. Therefore, there is no possibility that the current source 254 (*) affects the rank adjustment operation of the light emitting element L *.
　電圧計２６５（１）は、外部端子Ｔ４１と外部端子Ｔ４２との間に接続されている。電圧計２６５（２）は、外部端子Ｔ４２と外部端子Ｔ４３との間に接続されている。電圧計２６５（３）は、外部端子Ｔ４３と外部端子Ｔ４４との間に接続されている。すなわち、電圧計２６５（＊）は、発光部品２＊に対して並列に接続されており、発光ストリング２０に対して第１電流Ｉ１が印加されているときに各ランク抵抗Ｒ＊の両端間に現れる第１電圧Ｖ１（＊）をそれぞれ測定し、その測定結果を制御部２６６に出力する。 The voltmeter 265 (1) is connected between the external terminal T41 and the external terminal T42. The voltmeter 265 (2) is connected between the external terminal T42 and the external terminal T43. The voltmeter 265 (3) is connected between the external terminal T43 and the external terminal T44. That is, the voltmeter 265 (*) is connected in parallel to the light emitting component 2 *, and when the first current I1 is applied to the light emitting string 20, the voltage meter 265 (*) is connected between both ends of each rank resistor R *. The first voltage V <b> 1 (*) that appears is measured, and the measurement result is output to the control unit 266.
　制御部２６６は、第１電流Ｉ１と第１電圧Ｖ１（＊）からランク抵抗Ｒ＊の抵抗値を算出し、その演算結果（＝発光素子Ｌ＊毎のランク検出結果）に応じて、駆動電流Ｉｏｕｔの設定値Ｄｓｅｔとバイパス電流Ｉ４（＊）の電流値をそれぞれ調整する。なお、駆動電流Ｉｏｕｔの設定値Ｄｓｅｔをマイコン５０で調整する場合には、制御部２６６からマイコン５０に対してランク検出結果（＝ランク抵抗Ｒ＊の抵抗値）を通知してやればよい。また、バイパス電流Ｉ４（＊）の電流値をマイコン５０で調整する場合には、マイコン５０から制御部２６６に対してバイパス電流Ｉ４（＊）の設定値を通知してやればよい。 The control unit 266 calculates the resistance value of the rank resistor R * from the first current I1 and the first voltage V1 (*), and according to the calculation result (= rank detection result for each light emitting element L *), the drive current The set value Dset of Iout and the current value of the bypass current I4 (*) are adjusted. Note that when the microcomputer 50 adjusts the set value Dset of the drive current Iout, the control unit 266 may notify the microcomputer 50 of the rank detection result (= the resistance value of the rank resistance R *). When the microcomputer 50 adjusts the current value of the bypass current I4 (*), the microcomputer 50 may notify the control unit 266 of the set value of the bypass current I4 (*).
　また、制御部２６６は、マトリクススイッチＳＷ１～ＳＷ３のオン／オフ制御機能も備えている。より具体的に述べると、制御部２６６は、発光部品２１～２３の順次点灯制御に際してマトリクススイッチＳＷ１～ＳＷ３を適宜オン／オフ制御する一方、発光素子Ｌ１～Ｌ３のランク調整時には、ＳＷ１～ＳＷ３をいずれもオフさせる。従って、マトリクススイッチＳＷ＊が発光素子Ｌ＊のランク調整動作に悪影響を及ぼすおそれはない。 The control unit 266 also has an on / off control function for the matrix switches SW1 to SW3. More specifically, the control unit 266 appropriately controls on / off of the matrix switches SW1 to SW3 when sequentially controlling the lighting of the light emitting components 21 to 23, while adjusting the ranks of the light emitting elements L1 to L3. Both are turned off. Therefore, there is no possibility that the matrix switch SW * adversely affects the rank adjustment operation of the light emitting element L *.
　本実施形態のランク調整部２００は、基本的に第１実施形態（図３～図５を参照）と同じく、ランク抵抗Ｒ＊の抵抗値を個別に読み取って発光素子Ｌ＊のランクをそれぞれ検出し、最低ランクの発光素子が所望の輝度で発光するように駆動電流Ｉｏｕｔの設定値Ｄｓｅｔを調整する一方、それ以外の発光素子については駆動電流Ｉｏｕｔの余剰分をバイパス電流Ｉ４（＊）として迂回させる構成とされている。 The rank adjustment unit 200 of the present embodiment basically detects the rank of the light emitting element L * by individually reading the resistance value of the rank resistance R * as in the first embodiment (see FIGS. 3 to 5). Then, the set value Dset of the drive current Iout is adjusted so that the light emitting element of the lowest rank emits light with a desired luminance, while the surplus of the drive current Iout is bypassed as a bypass current I4 (*) for the other light emitting elements. It is supposed to be configured.
　このような構成とすることにより、第５実施形態の長所を損なうことなく、発光素子駆動装置１０の外部端子数を削減することが可能となる。 By adopting such a configuration, the number of external terminals of the light emitting element driving device 10 can be reduced without detracting from the advantages of the fifth embodiment.
＜ランク調整部（第３実施形態）＞
　図８は、ランク調整部２００の第３実施形態を示す回路図である。本実施形態のランク調整部２００は、電流源２７１と、スイッチ２７２と、電流源２７４（１）～（３）と、電圧計２７５（１）～（３）と、制御部２７６と、Ｐチャネル型ＭＯＳ電界効果トランジスタＰ１～Ｐ６と、を含む。 <Rank adjustment unit (third embodiment)>
FIG. 8 is a circuit diagram illustrating a third embodiment of the rank adjustment unit 200. The rank adjustment unit 200 of the present embodiment includes a current source 271, a switch 272, current sources 274 (1) to (3), voltmeters 275 (1) to (3), a control unit 276, and a P channel. Type MOS field effect transistors P1 to P6.
　電流源２７１は、電源端と外部端子Ｔ４１との間に接続されており、発光ストリング２０に第１電流Ｉ１を印加する。第１電流Ｉ１の電流値は、先にも述べたように、各ランク抵抗Ｒ＊の両端間電圧が各発光素子Ｌ＊の順方向降下電圧Ｖｆよりも高くならない範囲で適宜設定されている。 The current source 271 is connected between the power supply terminal and the external terminal T41, and applies the first current I1 to the light emitting string 20. As described above, the current value of the first current I1 is appropriately set within a range in which the voltage across the rank resistors R * does not become higher than the forward voltage drop Vf of each light emitting element L *.
　スイッチ２７２は、電流源２７１と外部端子Ｔ４１との間に接続されており、制御部２７６からの指示に応じてオン／オフされる。なお、スイッチ２７２は、発光素子Ｌ＊のランク調整期間にのみオンされる。従って、ランク調整部２００が発光ストリング２０の通常点灯動作に悪影響を及ぼすおそれはない。 The switch 272 is connected between the current source 271 and the external terminal T41, and is turned on / off according to an instruction from the control unit 276. The switch 272 is turned on only during the rank adjustment period of the light emitting element L *. Therefore, there is no possibility that the rank adjusting unit 200 adversely affects the normal lighting operation of the light emitting string 20.
　電流源２７４（＊）は、それぞれ、トランジスタＰ＊のドレインと接地端との間に接続されており、制御部２７６からの指示に応じて発光部品２＊毎のバイパス電流Ｉ４（＊）をそれぞれ生成する。 Each of the current sources 274 (*) is connected between the drain of the transistor P * and the ground terminal, and in response to an instruction from the control unit 276, the bypass current I4 (*) for each light emitting component 2 * is set. Generate.
　電圧計２７５（１）は、外部端子Ｔ４１と外部端子Ｔ４２との間に接続されている。電圧計２７５（２）は、外部端子Ｔ４２と外部端子Ｔ４３との間に接続されている。電圧計２７５（３）は、外部端子Ｔ４３と外部端子Ｔ４４との間に接続されている。すなわち、電圧計２７５（＊）は、発光部品２＊に対して並列に接続されており、発光ストリング２０に対して第１電流Ｉ１が印加されているときに各ランク抵抗Ｒ＊の両端間に現れる第１電圧Ｖ１（＊）をそれぞれ測定し、その測定結果を制御部２７６に出力する。 The voltmeter 275 (1) is connected between the external terminal T41 and the external terminal T42. The voltmeter 275 (2) is connected between the external terminal T42 and the external terminal T43. The voltmeter 275 (3) is connected between the external terminal T43 and the external terminal T44. That is, the voltmeter 275 (*) is connected in parallel to the light emitting component 2 *, and when the first current I1 is applied to the light emitting string 20, the voltage meter 275 (*) is connected between both ends of each rank resistor R *. The first voltage V <b> 1 (*) that appears is measured, and the measurement result is output to the control unit 276.
　制御部２７６は、第１電流Ｉ１と第１電圧Ｖ１（＊）からランク抵抗Ｒ＊の抵抗値を算出し、その演算結果（＝発光素子Ｌ＊毎のランク検出結果）に応じて、駆動電流Ｉｏｕｔの設定値Ｄｓｅｔとバイパス電流Ｉ４（＊）の電流値をそれぞれ調整する。なお、駆動電流Ｉｏｕｔの設定値Ｄｓｅｔをマイコン５０で調整する場合には、制御部２７６からマイコン５０に対してランク検出結果（＝ランク抵抗Ｒ＊の抵抗値）を通知してやればよい。また、バイパス電流Ｉ４（＊）の電流値をマイコン５０で調整する場合には、マイコン５０から制御部２７６に対してバイパス電流Ｉ４（＊）の設定値を通知してやればよい。 The control unit 276 calculates the resistance value of the rank resistor R * from the first current I1 and the first voltage V1 (*), and according to the calculation result (= rank detection result for each light emitting element L *), the drive current The set value Dset of Iout and the current value of the bypass current I4 (*) are adjusted. When the microcomputer 50 adjusts the set value Dset of the drive current Iout, the control unit 276 may notify the microcomputer 50 of the rank detection result (= the resistance value of the rank resistance R *). When the microcomputer 50 adjusts the current value of the bypass current I4 (*), the microcomputer 50 may notify the control unit 276 of the set value of the bypass current I4 (*).
　また、制御部２７６は、マトリクススイッチＳＷ１～ＳＷ３のオン／オフ制御機能も備えている。より具体的に述べると、制御部２７６は、発光部品２１～２３の順次点灯制御に際してマトリクススイッチＳＷ１～ＳＷ３を適宜オン／オフ制御する一方、発光素子Ｌ１～Ｌ３のランク調整時には、ＳＷ１～ＳＷ３をいずれもオフさせる。従って、マトリクススイッチＳＷ＊が発光素子Ｌ＊のランク調整動作に悪影響を及ぼすおそれはない。 The control unit 276 also has an on / off control function for the matrix switches SW1 to SW3. More specifically, the control unit 276 appropriately turns on / off the matrix switches SW1 to SW3 when sequentially controlling the lighting of the light emitting components 21 to 23, while adjusting the ranks of the light emitting elements L1 to L3. Both are turned off. Therefore, there is no possibility that the matrix switch SW * adversely affects the rank adjustment operation of the light emitting element L *.
　トランジスタＰ１のゲートは、トランジスタＰ１のドレイン、トランジスタＰ４のドレイン、及び、マトリクススイッチＳＷ１のゲートにそれぞれ接続されている。トランジスタＰ１のソースとトランジスタＰ４のソースは、いずれも外部端子Ｔ４１に接続されている。トランジスタＰ４のゲートは、制御部２７６に接続されている。 The gate of the transistor P1 is connected to the drain of the transistor P1, the drain of the transistor P4, and the gate of the matrix switch SW1. The source of the transistor P1 and the source of the transistor P4 are both connected to the external terminal T41. The gate of the transistor P4 is connected to the control unit 276.
　トランジスタＰ２のゲートは、トランジスタＰ２のドレイン、トランジスタＰ５のドレイン、及び、マトリクススイッチＳＷ２のゲートにそれぞれ接続されている。トランジスタＰ２のソースとトランジスタＰ５のソースは、いずれも外部端子Ｔ４２に接続されている。トランジスタＰ５のゲートは、制御部２７６に接続されている。 The gate of the transistor P2 is connected to the drain of the transistor P2, the drain of the transistor P5, and the gate of the matrix switch SW2. The source of the transistor P2 and the source of the transistor P5 are both connected to the external terminal T42. The gate of the transistor P5 is connected to the control unit 276.
　トランジスタＰ３のゲートは、トランジスタＰ３のドレイン、トランジスタＰ６のドレイン、及び、マトリクススイッチＳＷ３のゲートにそれぞれ接続されている。トランジスタＰ３のソースとトランジスタＰ６のソースは、いずれも外部端子Ｔ４３に接続されている。トランジスタＰ６のゲートは、制御部２７６に接続されている。 The gate of the transistor P3 is connected to the drain of the transistor P3, the drain of the transistor P6, and the gate of the matrix switch SW3. The source of the transistor P3 and the source of the transistor P6 are both connected to the external terminal T43. The gate of the transistor P6 is connected to the control unit 276.
　このように、トランジスタＰ１～Ｐ３は、それぞれ、マトリクススイッチＳＷ１～ＳＷ３と一対を成すように設けられており、電流源２７４（１）～（３）で生成されるバイパス電流Ｉ４（１）～（３）をそれぞれミラーしてマトリクススイッチＳＷ１～ＳＷ３に流し込むカレントミラーを形成している。 Thus, the transistors P1 to P3 are provided so as to form a pair with the matrix switches SW1 to SW3, respectively, and the bypass currents I4 (1) to (3) generated by the current sources 274 (1) to (3) are provided. 3) are mirrored to form current mirrors that flow into the matrix switches SW1 to SW3.
　本実施形態のランク調整部２００は、基本的に第１実施形態（図３～図５）や第２実施形態（図７）と同じく、ランク抵抗Ｒ＊の抵抗値を個別に読み取って発光素子Ｌ＊のランクをそれぞれ検出し、最低ランクの発光素子が所望の輝度で発光するように駆動電流Ｉｏｕｔの設定値Ｄｓｅｔを調整する一方、それ以外の発光素子については駆動電流Ｉｏｕｔの余剰分をバイパス電流Ｉ４（＊）として迂回させる構成とされている。 The rank adjustment unit 200 according to the present embodiment basically reads the resistance value of the rank resistance R * individually as in the first embodiment (FIGS. 3 to 5) and the second embodiment (FIG. 7). Each of the L * ranks is detected, and the set value Dset of the drive current Iout is adjusted so that the light emitting element of the lowest rank emits light with a desired luminance, while the surplus of the drive current Iout is bypassed for the other light emitting elements. The current I4 (*) is bypassed.
　特に、本実施形態のランク調整部２００では、スイッチ駆動装置４０に元々設けられているマトリクススイッチＳＷ＊を流用してバイパス電流Ｉ４（＊）が迂回されている。このような構成とすることにより、スイッチ駆動装置４０の既存設計を殆ど変更することなく、ランク調整部２００を実装することが可能となる。 In particular, in the rank adjustment unit 200 of the present embodiment, the bypass current I4 (*) is bypassed by diverting the matrix switch SW * originally provided in the switch driving device 40. With such a configuration, it is possible to mount the rank adjustment unit 200 with almost no change to the existing design of the switch drive device 40.
　なお、例えば、発光部品２１を消灯する場合には、トランジスタＰ４をオフした上で、ランク抵抗Ｒ１の両端間電圧が発光素子Ｌ１の順方向降下電圧Ｖｆよりも高くならないように、バイパス電流Ｉ４（１）を駆動電流Ｉｏｕｔと同程度の電流値に設定すればよい。発光部品２２または２３を消灯する場合についても、上記と同様であり、トランジスタＰ５またはＰ６をオフした上で、バイパス電流Ｉ４（２）またはＩ４（３）を駆動電流Ｉｏｕｔと同程度の電流値に設定すればよい。 For example, when the light emitting component 21 is turned off, the bypass current I4 ((4) is set so that the voltage across the rank resistor R1 does not become higher than the forward drop voltage Vf of the light emitting element L1 after the transistor P4 is turned off. 1) may be set to a current value comparable to the drive current Iout. The same applies to the case where the light-emitting component 22 or 23 is turned off. The transistor P5 or P6 is turned off, and the bypass current I4 (2) or I4 (3) is set to the same current value as the drive current Iout. You only have to set it.
　一方、例えば、発光部品２１に駆動電流Ｉｏｕｔをそのまま供給する場合（発光部品２１～２３のうち発光部品２１が最低ランクである場合）には、トランジスタＰ４をオンすることにより、マトリクススイッチＳＷ１を完全にオフしてやればよい。発光部品２２または２３に駆動電流Ｉｏｕｔをそのまま供給する場合にについても、上記と同様であり、トランジスタＰ５またはＰ６をオンすることにより、マトリクススイッチＳＷ２またはＳＷ３を完全にオフしてやればよい。 On the other hand, for example, when the drive current Iout is supplied to the light emitting component 21 as it is (when the light emitting component 21 has the lowest rank among the light emitting components 21 to 23), the matrix switch SW1 is completely turned on by turning on the transistor P4. Just turn it off. The same applies to the case where the drive current Iout is supplied to the light emitting component 22 or 23 as it is, and the matrix switch SW2 or SW3 may be completely turned off by turning on the transistor P5 or P6.
＜変形例＞
　図９は、発光装置の第１変形例を示す回路図である。本変形例の発光装置５００は、電流源５１１～５１４と、スイッチ５２１～５２４と、発光部品５３１～５３４と、電圧計５４１～５４４と、を有する。 <Modification>
FIG. 9 is a circuit diagram illustrating a first modification of the light emitting device. The light emitting device 500 of this modification includes current sources 511 to 514, switches 521 to 524, light emitting components 531 to 534, and voltmeters 541 to 544.
　電流源５１１～５１４の第１端は、いずれも電源端に接続されている。電流源５１１～５１１～５１４の第２端は、それぞれ、スイッチ５２１～５２４の第１端に接続されている。スイッチ５２１～５２４の第２端は、それぞれ、発光部品５３１～５３４のアノードに接続されている。発光部品５３１～５３４のカソードは、いずれも接地端に接続されている。なお、発光部品５３１～５３４は、発光素子とランク抵抗を並列に含む。電圧計５４１～５４４は、それぞれ、発光部品５３１～５３４に並列接続されている。 The first ends of the current sources 511 to 514 are all connected to the power supply end. Second ends of the current sources 511 to 511 to 514 are connected to first ends of the switches 521 to 524, respectively. Second ends of the switches 521 to 524 are connected to anodes of the light emitting components 531 to 534, respectively. The cathodes of the light emitting components 531 to 534 are all connected to the ground terminal. Note that the light emitting components 531 to 534 include a light emitting element and a rank resistor in parallel. The voltmeters 541 to 544 are connected in parallel to the light emitting components 531 to 534, respectively.
　このように、並列に接続された発光部品５３１～５３４についても、電圧計５４１～５４４を用いてランク抵抗値を測定し、その測定結果に応じて電流源５１１～５１４で生成される駆動電流値を適宜設定することが可能である。 Thus, the rank resistance values of the light emitting components 531 to 534 connected in parallel are also measured using the voltmeters 541 to 544, and the drive current values generated by the current sources 511 to 514 according to the measurement results. Can be set as appropriate.
　図１０は、発光装置の第２変形例を示す回路図である。本変形例の発光装置６００は、電流源６０１及び６０２と、スイッチ６０３と、発光部品６０４と、電圧計６０５と、を含む。 FIG. 10 is a circuit diagram showing a second modification of the light emitting device. The light emitting device 600 of this modification includes current sources 601 and 602, a switch 603, a light emitting component 604, and a voltmeter 605.
　電流源６０１及び６０２の第１端は、いずれも電源端に接続されている。電流源６０１及び６０２の第２端は、それぞれ、スイッチ６０３の第１選択端及び第２選択端に接続されている。スイッチ６０３の共通端は、発光部品６０４のアノードに接続されている。発光部品６０４のカソードは、接地端に接続されている。なお、発光部品６０４は、発光素子とランク抵抗を並列に含む。電圧計６０５は、発光部品６０４に並列接続されている。 The first ends of the current sources 601 and 602 are both connected to the power supply end. The second ends of the current sources 601 and 602 are connected to the first selection end and the second selection end of the switch 603, respectively. The common end of the switch 603 is connected to the anode of the light emitting component 604. The cathode of the light emitting component 604 is connected to the ground terminal. The light emitting component 604 includes a light emitting element and a rank resistor in parallel. The voltmeter 605 is connected to the light emitting component 604 in parallel.
　このように、電圧計６０５での測定結果に応じた可変電流（ドライブ用）を生成する電流源６０１と、固定電流（ランク検出用）を生成する電流源６０２とを並列に設け、スイッチ６０３を用いて両者を切り替える構成としてもよい。 As described above, the current source 601 that generates a variable current (for driving) according to the measurement result of the voltmeter 605 and the current source 602 that generates a fixed current (for rank detection) are provided in parallel, and the switch 603 is provided. It is good also as a structure which uses and switches both.
　図１１は、発光装置の第３変形例を示す回路図である。本変形例の発光装置７００は、電流源７０１及び７０２と、スイッチ７０３と、発光部品７０４と、電圧計７０５と、を含む。 FIG. 11 is a circuit diagram showing a third modification of the light emitting device. A light emitting device 700 according to this modification includes current sources 701 and 702, a switch 703, a light emitting component 704, and a voltmeter 705.
　電流源７０１の第１端は、電源端に接続されている。電流源７０１の第２端は、スイッチ７０３の第１端に接続されている。スイッチ７０３の第２端は、発光部品７０４のアノードに接続されている。発光部品７０４のカソードは、接地端に接続されている。なお、発光部品７０４は、発光素子とランク抵抗を並列に含む。電流源７０２及び電圧計７０５は、いずれも発光部品７０４に並列接続されている。 The first end of the current source 701 is connected to the power supply end. The second end of the current source 701 is connected to the first end of the switch 703. A second end of the switch 703 is connected to the anode of the light emitting component 704. The cathode of the light emitting component 704 is connected to the ground terminal. The light emitting component 704 includes a light emitting element and a rank resistor in parallel. Both the current source 702 and the voltmeter 705 are connected in parallel to the light emitting component 704.
　このように、固定電流（ドライブ用）を生成する電流源７０１のほかに、電圧計７０５での測定結果に応じた可変電流（バイパス用）を生成する電流源７０２を設け、発光部品７０４にとって余剰な電流をバイパスさせる構成としてもよい。 As described above, in addition to the current source 701 that generates a fixed current (for driving), a current source 702 that generates a variable current (for bypass) according to the measurement result of the voltmeter 705 is provided, which is a surplus for the light emitting component 704. It is good also as a structure which bypasses an electric current.
＜車両への適用＞
　発光装置１は、例えば、図１２及び図１３で示す通り、車両Ｘ１０のヘッドライト（ハイビーム／ロービーム／スモールランプ／フォグランプなどを適宜含む）Ｘ１１、白昼夜走行（ＤＲＬ）用光源Ｘ１２、テールランプ（スモールランプやバックランプなどを適宜含む）Ｘ１３、ストップランプＸ１４、及び、ターンランプＸ１５などとして好適に用いることができる。 <Application to vehicles>
For example, as shown in FIGS. 12 and 13, the light-emitting device 1 includes a headlight (including a high beam / low beam / small lamp / fog lamp, etc.) X11 of a vehicle X10, a light source X12 for day / night driving (DRL), a tail lamp (small). (Including lamps and back lamps as appropriate) X13, stop lamp X14, turn lamp X15, and the like.
　なお、発光素子駆動装置１０は、駆動対象となる発光ストリング２０と共にモジュール（図１４のＬＥＤヘッドライトモジュールＹ１０、図１５のＬＥＤターンランプモジュールＹ２０、及び、図１６のＬＥＤリアランプモジュールＹ３０など）として提供されるものであってもよいし、発光ストリング２０とは独立にＩＣ単体として提供されるものであってもよい。 The light emitting element driving device 10 is provided as a module (LED headlight module Y10 in FIG. 14, LED turn lamp module Y20 in FIG. 15, LED rear lamp module Y30 in FIG. 16, etc.) together with the light emitting string 20 to be driven. It may be provided, or may be provided as a single IC independently of the light-emitting string 20.
＜その他の変形例＞
　なお、上記の実施形態では、発光素子として発光ダイオード素子を用いた構成を例に挙げて説明を行ったが、本発明の構成はこれに限定されるものではなく、例えば、発光素子として有機ＥＬ［electro-luminescence］素子を用いることも可能である。 <Other variations>
In the above embodiment, the configuration using a light emitting diode element as a light emitting element has been described as an example. However, the configuration of the present invention is not limited to this, and for example, an organic EL as a light emitting element. It is also possible to use an [electro-luminescence] element.
　このように、本明細書中に開示されている種々の技術的特徴は、上記実施形態のほか、その技術的創作の主旨を逸脱しない範囲で種々の変更を加えることが可能である。すなわち、上記実施形態は、全ての点で例示であって、制限的なものではないと考えられるべきであり、本発明の技術的範囲は、上記実施形態の説明ではなく、特許請求の範囲によって示されるものであり、特許請求の範囲と均等の意味及び範囲内に属する全ての変更が含まれると理解されるべきである。 As described above, various technical features disclosed in the present specification can be variously modified within the scope of the technical creation in addition to the above-described embodiment. That is, the above-described embodiment is an example in all respects and should not be considered as limiting, and the technical scope of the present invention is not the description of the above-described embodiment, but the claims. It should be understood that all modifications that come within the meaning and range of equivalents of the claims are included.
　本明細書中に開示されている発明は、例えば、車載用エクステリアランプやイルミネーションランプなど（特に、法律などにより輝度が厳格に定められている発光装置）に利用することが可能である。 The invention disclosed in the present specification can be used for, for example, an in-vehicle exterior lamp, an illumination lamp, and the like (particularly, a light emitting device whose luminance is strictly determined by law or the like).
　　　１　　発光装置
　　　１０　　発光素子駆動装置
　　　２０　　発光ストリング
　　　２１、２２、２３　　発光部品
　　　３０　　センス抵抗
　　　４０　　スイッチ駆動装置
　　　５０　　マイコン
　　　１００　　駆動部
　　　１０１　　出力トランジスタ（Ｐチャネル型ＭＯＳ電界効果トランジスタ）
　　　１０２　　差動アンプ
　　　１０３　　デジタル／アナログ変換部
　　　１０４　　オペアンプ
　　　２００　　ランク調整部
　　　２５１、２６１、２７１　　電流源
　　　２５２、２６２、２７２　　スイッチ
　　　２５６、２６６、２７６　　制御部
　　　２５３（＊）、２６３（＊）　　スイッチ
　　　２５４（＊）、２６４（＊）、２７４（＊）　　電流源
　　　２５５（＊）、２６５（＊）、２７５（＊）　　電圧計
　　　５００、６００、７００　　発光装置
　　　５１１～５１４、６０１、６０２、７０１、７０２　　電流源
　　　５２１～５２４、６０３、７０３　　スイッチ
　　　５３１～５３４、６０４、７０４　　発光部品
　　　５４１～５４４、６０５、７０６　　電圧計
　　　Ｌ１、Ｌ２、Ｌ３　　発光素子（発光ダイオード）
　　　Ｒ１、Ｒ２、Ｒ３　　ランク抵抗
　　　ＳＷ１、ＳＷ２、ＳＷ３　　マトリクススイッチ
　　　Ｐ１～Ｐ６　　Ｐチャネル型ＭＯＳ電界効果トランジスタ
　　　Ｔ１１～Ｔ１４、Ｔ１７、Ｔ２１～Ｔ２３、Ｔ４１～Ｔ４４　　外部端子
　　　Ｘ１０　　車両
　　　Ｘ１１　　ヘッドライト
　　　Ｘ１２　　白昼夜走行（ＤＲＬ）用光源
　　　Ｘ１３　　テールランプ
　　　Ｘ１４　　ストップランプ
　　　Ｘ１５　　ターンランプ
　　　Ｙ１０　　ＬＥＤヘッドライトモジュール
　　　Ｙ２０　　ＬＥＤターンランプモジュール
　　　Ｙ３０　　ＬＥＤリアランプモジュール DESCRIPTION OF SYMBOLS 1 Light emitting device 10 Light emitting element drive device 20 Light emitting string 21, 22, 23 Light emitting component 30 Sense resistance 40 Switch drive device 50 Microcomputer 100 Drive part 101 Output transistor (P channel type MOS field effect transistor)
102 Differential Amplifier 103 Digital / Analog Conversion Unit 104 Operational Amplifier 200 Rank Adjustment Unit 251, 261, 271 Current Source 252, 262, 272 Switch 256, 266, 276 Control Unit 253 (*), 263 (*) Switch 254 (*) H.264 (*), 274 (*) Current source 255 (*), 265 (*), 275 (*) Voltmeter 500, 600, 700 Light emitting device 511 to 514, 601, 602, 701, 702 Current source 521 to 524, 603, 703 Switch 531 to 534, 604, 704 Light emitting component 541 to 544, 605, 706 Voltmeter L1, L2, L3 Light emitting element (light emitting diode)
R1, R2, R3 Rank resistance SW1, SW2, SW3 Matrix switch P1 to P6 P-channel MOS field effect transistors T11 to T14, T17, T21 to T23, T41 to T44 External terminal X10 Vehicle X11 Headlight X12 Day / night driving (DRL) ) Light source X13 Tail lamp X14 Stop lamp X15 Turn lamp Y10 LED headlight module Y20 LED turn lamp module Y30 LED rear lamp module

Claims (11)

  1. 　発光素子とランク抵抗を並列に内蔵した発光部品を複数直列に接続して成る発光ストリングに駆動電流を供給する駆動部と；
    　各ランク抵抗の抵抗値を個別に読み取って各発光素子のランクをそれぞれ検出し、最低ランクの発光素子が所望の輝度で発光するように前記駆動電流の設定値を調整する一方、それ以外の発光素子については前記駆動電流の余剰分をバイパス電流として迂回させるランク調整部と；
    　を有することを特徴とする発光素子駆動装置。     A drive unit that supplies a drive current to a light-emitting string formed by connecting a plurality of light-emitting components that incorporate a light-emitting element and a rank resistor in parallel;
    The resistance value of each rank resistance is individually read to detect the rank of each light emitting element, and the set value of the drive current is adjusted so that the light emitting element of the lowest rank emits light with a desired luminance, while the other light emission A rank adjustment unit for bypassing the surplus of the drive current as a bypass current for the element;
    A light-emitting element driving device comprising:
  2. 　前記ランク調整部は、
    　各ランク抵抗の両端間電圧が各発光素子の順方向降下電圧よりも高くならない範囲で前記発光ストリングに所定の第１電流を印加する第１電流源と；
    　前記第１電流が印加されているときに各ランク抵抗の両端間にそれぞれ現れる複数の第１電圧をそれぞれ測定する複数の電圧計と；
    　各発光部品毎のバイパス電流をそれぞれ生成する複数の第２電流源と；
    　前記第１電流と前記複数の第１電圧から各ランク抵抗の抵抗値を算出し、その演算結果に応じて前記駆動電流の設定値と各バイパス電流の設定値を調整する制御部と；
    　を含むことを特徴とする請求項１に記載の発光素子駆動装置。     The rank adjuster is
    A first current source that applies a predetermined first current to the light-emitting string in a range in which a voltage between both ends of each rank resistor does not become higher than a forward voltage drop of each light-emitting element;
    A plurality of voltmeters respectively measuring a plurality of first voltages respectively appearing across the rank resistors when the first current is applied;
    A plurality of second current sources each generating a bypass current for each light emitting component;
    A control unit that calculates a resistance value of each rank resistor from the first current and the plurality of first voltages, and adjusts a setting value of the driving current and a setting value of each bypass current according to the calculation result;
    The light-emitting element driving device according to claim 1, comprising:
  3. 　発光素子とランク抵抗を並列に内蔵した複数の発光部品に対してそれぞれ並列に接続された複数のマトリクススイッチと；
    　各ランク抵抗の抵抗値を個別に読み取って各発光素子のランクをそれぞれ検出し、最低ランクの発光素子が所望の輝度で発光するように前記複数の発光部品に供給される駆動電流の設定値を調整する一方、それ以外の発光素子については前記駆動電流の余剰分をバイパス電流として迂回させるランク調整部と；
    　を有することを特徴とするスイッチ駆動装置。     A plurality of matrix switches connected in parallel to a plurality of light-emitting components each incorporating a light-emitting element and a rank resistor in parallel;
    The resistance value of each rank resistor is individually read to detect the rank of each light emitting element, and the setting value of the drive current supplied to the plurality of light emitting components is set so that the light emitting element of the lowest rank emits light with a desired luminance. While adjusting, a rank adjusting unit that bypasses an excess of the drive current as a bypass current for the other light emitting elements;
    A switch driving device comprising:
  4. 　前記ランク調整部は、
    　各ランク抵抗の両端間電圧が各発光素子の順方向降下電圧よりも高くならない範囲で前記発光ストリングに所定の第１電流を印加する第１電流源と；
    　前記第１電流が印加されているときに各ランク抵抗の両端間にそれぞれ現れる複数の第１電圧をそれぞれ測定する複数の電圧計と；
    　各発光部品毎のバイパス電流をそれぞれ生成する複数の第２電流源と；
    　前記第１電流と前記複数の第１電圧から各ランク抵抗の抵抗値を算出し、その演算結果に応じて前記駆動電流の設定値と各バイパス電流の設定値を調整する制御部と；
    　を含むことを特徴とする請求項３に記載のスイッチ駆動装置。     The rank adjuster is
    A first current source that applies a predetermined first current to the light-emitting string in a range in which a voltage between both ends of each rank resistor is not higher than a forward voltage drop of each light-emitting element;
    A plurality of voltmeters respectively measuring a plurality of first voltages respectively appearing across the rank resistors when the first current is applied;
    A plurality of second current sources each generating a bypass current for each light emitting component;
    A control unit that calculates a resistance value of each rank resistor from the first current and the plurality of first voltages, and adjusts a setting value of the driving current and a setting value of each bypass current according to the calculation result;
    The switch driving device according to claim 3, comprising:
  5. 　前記ランク調整部は、各バイパス電流をミラーして前記複数のマトリクススイッチに流し込む複数のカレントミラーをさらに含むことを特徴とする請求項４に記載のスイッチ駆動装置。 5. The switch driving device according to claim 4, wherein the rank adjusting unit further includes a plurality of current mirrors that mirror each bypass current and flow it into the plurality of matrix switches.
  6. 　発光素子とランク抵抗を並列に内蔵した発光部品を複数直列に接続して成る発光ストリングと、
    　請求項１または請求項２に記載の発光素子駆動装置と、
    　を有することを特徴とする発光装置。     A light-emitting string formed by connecting a plurality of light-emitting components that incorporate a light-emitting element and a rank resistor in parallel;
    The light-emitting element driving device according to claim 1 or 2,
    A light emitting device comprising:
  7. 　発光素子とランク抵抗を並列に内蔵した発光部品を複数直列に接続して成る発光ストリングと、
    　前記発光ストリングに駆動電流を供給する発光素子駆動装置と；
    　請求項３～請求項５のいずれか一項に記載のスイッチ駆動装置と、
    　前記発光素子駆動装置及び前記スイッチ駆動装置を統括制御するマイコンと；
    　を有することを特徴とする発光装置。     A light-emitting string formed by connecting a plurality of light-emitting components that incorporate a light-emitting element and a rank resistor in parallel;
    A light emitting element driving device for supplying a driving current to the light emitting string;
    The switch driving device according to any one of claims 3 to 5,
    A microcomputer for comprehensively controlling the light emitting element driving device and the switch driving device;
    A light emitting device comprising:
  8. 　前記発光素子は、発光ダイオード素子、または、有機ＥＬ素子であることを特徴とする請求項６または請求項７に記載の発光装置。 The light emitting device according to claim 6 or 7, wherein the light emitting element is a light emitting diode element or an organic EL element.
  9. 　ヘッドライトモジュール、ターンランプモジュール、または、リアランプモジュールとして車両に装着されることを特徴とする請求項６～請求項８のいずれか一項に記載の発光装置。 The light emitting device according to any one of claims 6 to 8, wherein the light emitting device is mounted on a vehicle as a headlight module, a turn lamp module, or a rear lamp module.
  10. 　請求項６～請求項９のいずれか一項に記載の発光装置を有する車両。 A vehicle having the light emitting device according to any one of claims 6 to 9.
  11. 　前記発光装置は、ヘッドライト、白昼夜走行用光源、テールランプ、ストップランプ、及び、ターンランプの少なくとも一つとして用いられることを特徴とする請求項１０に記載の車両。 The vehicle according to claim 10, wherein the light emitting device is used as at least one of a headlight, a light source for driving day and night, a tail lamp, a stop lamp, and a turn lamp.
PCT/JP2016/061337 2015-06-02 2016-04-07 Light-emitting element drive device, and switch drive device WO2016194469A1 (en)

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