EP3484248A1 - Rückbeleuchtungseinheit und verfahren zur steuerung der rückbeleuchtung - Google Patents

Rückbeleuchtungseinheit und verfahren zur steuerung der rückbeleuchtung Download PDF

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Publication number
EP3484248A1
EP3484248A1 EP17201435.9A EP17201435A EP3484248A1 EP 3484248 A1 EP3484248 A1 EP 3484248A1 EP 17201435 A EP17201435 A EP 17201435A EP 3484248 A1 EP3484248 A1 EP 3484248A1
Authority
EP
European Patent Office
Prior art keywords
led
string
backlight
leds
output voltage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP17201435.9A
Other languages
English (en)
French (fr)
Inventor
Matthias Koerber
Helmut Noeth
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Delphi Technologies Inc
Original Assignee
Delphi Technologies Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Delphi Technologies Inc filed Critical Delphi Technologies Inc
Priority to EP17201435.9A priority Critical patent/EP3484248A1/de
Publication of EP3484248A1 publication Critical patent/EP3484248A1/de
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/40—Details of LED load circuits
    • H05B45/44—Details of LED load circuits with an active control inside an LED matrix
    • H05B45/46—Details of LED load circuits with an active control inside an LED matrix having LEDs disposed in parallel lines
    • 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
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/10—Controlling the intensity of the light
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/06—Adjustment of display parameters
    • G09G2320/0626—Adjustment of display parameters for control of overall brightness
    • G09G2320/064—Adjustment of display parameters for control of overall brightness by time modulation of the brightness of the illumination source
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/02—Details of power systems and of start or stop of display operation
    • G09G2330/021—Power management, e.g. power saving
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/02—Details of power systems and of start or stop of display operation
    • G09G2330/028—Generation of voltages supplied to electrode drivers in a matrix display other than LCD
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2380/00—Specific applications
    • G09G2380/10—Automotive applications
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G09G3/342—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
    • 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
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/50—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
    • H05B45/54—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits in a series array of LEDs

Definitions

  • the present invention relates to a backlight unit and more particularly to a method for controlling a backlight module of the backlight unit.
  • Vehicles are generally equipped with displays that are backlighted by arrays of light emitting diodes (LEDs).
  • the arrays of LEDs generally comprise several strings of a plurality of serial LEDs. Basically, the power supply of the strings of LEDs is from a boost topology that elevates the battery voltage such that the LEDs of the strings are in conduction mode and illuminate the display.
  • a backlight unit for a vehicle comprises a backlight module comprising at least a first string of a plurality of serials LEDs, the plurality of serials LEDs being ranked 1 to N from a first LED to a last LED in series; a power supply unit configured to provide an operating output voltage to the backlight module from a battery voltage; the operating output voltage being electrically connected to the first LED of each string; a first dimming control unit electrically connected to the last LED of each string of the plurality of serials LEDs and configured to control the illumination of the plurality of serials LEDs of each string representative to received first dimming levels; a backlight controller electrically connected to the first dimming control unit and configured to provide first dimming levels between 0% of illumination and 100% of illumination to the first diming control unit; and a second dimming control unit electrically connected between the first LED and the second LED of each string and configured to control the illumination of only the first LED of each string representative to received second dimming levels.
  • the backlight controller is electrically connected to the second
  • the power supply unit may comprise a boost topology and a bypass topology and the backlight controller may be electrically connected to the power supply and may be configured to select and to control one of the boost, and the bypass topology to provide the operating output voltage to operate the first and the second dimming levels.
  • the bypass technology allows the non-use of the boost in case of elevation of battery voltage is not needed.
  • the backlight unit may comprise a battery voltage supervisor electrically connected to the battery voltage and electrically connected to the backlight controller, said battery voltage supervisor being configured to provide a battery voltage value to the backlight controller such that said backlight controller may determine if boost topology is needed.
  • the backlight unit may comprise a voltage drop sensor or a current drop sensor electrically connected to the backlight controller and electrically connected between the first and the second LED, said voltage/current drop sensor being configured to provide a voltage drop value or a current drop value through the first LED to the backlight controller such that the backlight controller may diagnose the state of the serial LEDs, i.e. the backlight controller may determine if one LED of serial LEDs is damaged as in short circuit mode or open circuit mode.
  • the backlight unit may comprise a fail safe mode wherein the backlight controller is configured to provide the second dimming levels greater than 0% illumination and the first dimming levels equal to 0% illumination.
  • the backlight controller may be configured to determine the operating output voltage value from the current/voltage drop values and the second dimming levels; and to select the boost topology of the power supply unit if the determined operating output voltage value is greater than the battery voltage value; and to select the bypass topology of the power supply unit if the determined operating output voltage value is equal or lower than the battery voltage value.
  • the power supply unit may comprise a buck topology, and the backlight controller may be configured to select the buck topology if the determined operating output voltage value is less than the battery voltage value instead of selecting the bypass topology.
  • an assembly comprises a backlight unit as described above and a warning indicator such that the first LED of a first string cooperates with the warning indicator of the vehicle such that said first LED is arranged to backlight the warning indicator of the vehicle.
  • the backlight module may comprise a second string of a plurality of serials LEDs, said plurality of serials LEDs of the second string being ranked 1 to M from a first LED to a last LED in series; the first LED of the second string may cooperate with the warning indicator of the vehicle such that said first LED of the second string is arranged to backlight the warning indicator of the vehicle.
  • a method for controlling a backlight module for a vehicle comprising at least a first string of a plurality of serials LEDs, the plurality of serials LEDs being ranked 1 to N from a first LED to a last LED in series; comprises the steps of:
  • the method may comprise a fail safe mode comprising the steps of:
  • the method in that the fail safe mode may comprise the steps of:
  • the method according in fail safe mode may further comprise the steps of:
  • a method for backlighting a warning indicator of a vehicle comprises the steps of the method for controlling a backlight module and further comprises a step of:
  • the method for backlighting the warning indicator may comprise a step of:
  • Figure 1 shows a backlight unit 10 for a vehicle comprising basically a backlight module 12, a power supply unit 14 and a first dimming control unit 16.
  • the backlight module 12 comprises generally several strings 18, 20 of a plurality of light emitting diodes (LEDs) 22, 24, 26, 28.
  • LEDs light emitting diodes
  • each string comprises LEDs 22, 24, 26, 28 electrically connected in series.
  • the cathode 30 of one LED 22 of a string 18 is connected to the anode 32 of the LED 24 connected with said one LED 22.
  • the strings 18, 20 may have a different number N, M of LEDs 22, 24, 26, 28 in series.
  • the power supply unit 14 is configured to provide an operating output voltage 34 to the backlight module 12.
  • the power supply unit 14 regulates a battery voltage 36 of a battery 38 of the vehicle such that it provides the operating output voltage 34 of the backlight module 12. More particularly, the operating output voltage 24 is electrically connected to the anode 32 of the first LED 22, 28 of each string 18, 20 such that a voltage is applied between the anode 32 of the first LED 22, 28 of each string 18, 20 and the electrical ground 40.
  • the first dimming control unit 16 is configured to control the illumination of the plurality of serials LEDs 22, 24, 26 of each string 18, 20 according to first dimming levels.
  • the first dimming control unit 16 is electrically connected to the last LED 26 of each string 18, 20 of the plurality of serials LEDs 22, 24, 26. More particularly, the first dimming control unit 16 is electrically connected to the cathode 30 of the last LED 26 of each string 18, 20 such that said first dimming control unit 16 is configured to switch the cathode 30 of the last LED 26 of each string 18, 20 to the electrical ground 40.
  • the first dimming control unit 16 is applying first dimming levels between 0% and 100% such that the intensity of the plurality of serials LEDs 22, 24, 26 of each string 18, 20 may be adjusted between no illumination and maximum illumination.
  • the first dimming level is a duty cycle of a pulse width modulation (PWM) signal controlling a mean of switching the cathode 30 of the last LED 26 to the electrical ground 40 such that said cathode 26 of the last LED 26 may be connected to the electrical ground 40 from 0% of the time, i.e. no connection to the electrical ground 40 and so no illumination, to 100% of the time, i.e. permanent connection to the electrical ground 40 and so a maximum illumination.
  • PWM pulse width modulation
  • the mean of switching may be a Metal Oxide Semiconductor Field Effect Transistor (MOSFET transistor) wherein the gate is controlled by the PWM signal, the drain is electrically connected to the cathode 30 of the last LED 26, and the source is electrically connected to the electrical ground 40.
  • MOSFET transistor Metal Oxide Semiconductor Field Effect Transistor
  • the backlight unit 10 comprises a backlight controller 42 that provides the first dimming levels to the first dimming control unit 16.
  • the backlight controller 42 is also electrically connected to the power supply unit 14 such that it controls the operating output voltage 34.
  • the power supply unit 14 is a switch mode power supply comprising a boost topology 44 and a bypass topology 46, the backlight controller 42 being configured to select and to control one of the boost topology 44, and the bypass topology 46 to provide the operating output voltage 34 to operate the first dimming levels.
  • the backlight controller 42 selects the boost topology 44 when an elevation of the battery voltage 36 is needed to operate the backlight module 12.
  • An elevation of the battery voltage 36 may be needed during a start phase of the engine of the vehicle or in temperature conditions below 0 degree Celsius.
  • An elevation of the battery voltage 36 may be also needed if a string 18 of LEDs 22, 24, 26 comprises a number N of LEDs 22, 24, 26 in series such that the operating output voltage 34 has to be greater than a nominal battery voltage value to get all the LEDs 22, 24, 26 in conduction mode.
  • a nominal battery voltage value is considered as the most common battery voltage of the vehicle equipped with a new battery.
  • a battery for a thermal engine may have a nominal battery voltage value around 12.6 volts.
  • the backlight unit 10 further comprises a battery voltage supervisor 48 electrically connected to the battery voltage 36 and electrically connected to the backlight controller 42, said battery voltage supervisor 48 being configured to measure the battery voltage 36 and to provide a battery voltage value to the backlight controller 42.
  • the backlight controller 42 may select the bypass topology 46 or the boost topology 44 of the power supply unit 14 such that the operating output voltage 34 is high enough to get the LEDs 22, 24, 26 of each string 18, 20 in conduction mode.
  • the backlight controller 42 controls the boost topology 44 by controlling the switching frequency of the switching mode power supply.
  • the backlight unit 10 further comprises a first voltage drop sensor 50 or a first current drop sensor electrically connected to the backlight controller 42 and electrically connected to the cathode 30 of the last LED 26 of each string 18, 20, said first voltage drop sensor 50 or first current drop sensor being configured to measure a first voltage drop value or a first current drop value through each string 18, 20 and to provide the first voltage drop values or the first current drop values to the backlight controller 42.
  • the backlight controller 42 may diagnose each string 18, 20, i.e.
  • said backlight controller 42 may identify if one or several LEDs 22, 24, 26 of each string 18, 20 are damaged such that one or several LEDs 22, 24 of the plurality of serial LEDs 22, 24, 26 are in short circuit mode or in open circuit mode. According to said diagnostic, the backlight controller 42 may adjust the first dimming levels, and/or selecting the bypass topology 46 or the boost topology 44 of the power supply unit 14 such that the operating output voltage 34 is high enough to get the LEDs 22, 24, 26 of each string 18, 20 in conduction mode.
  • the first voltage drop sensor 50 or the first current drop sensor may comprise a resistor switched to the electrical ground 40 during measurement such that a voltage drop value or a current drop value may be measured and converted digitally by an analog to digital converter (ADC).
  • ADC analog to digital converter
  • the backlight controller 42 may select the bypass topology 46 or the boost topology 44 of the power supply unit 14 such that the operating output voltage 34 is high enough to get the LEDs 22, 24, 26 of each string 18, 20 in conduction mode.
  • Figure 2 illustrates a further refined and preferred embodiment of the invention.
  • the drawing shows similar components and reference numerals as before.
  • the embodiment further however includes a second dimming control unit 52 and optionally, a second voltage drop sensor 54 or a second current drop sensor.
  • the second dimming control unit 52 is electrically connected between the first LED 22 and the second LED 24 of each string 18, 20 and is configured to control the illumination of only the first LED 22 of each string 18, 20 representative to received second dimming levels.
  • the backlight controller 42 is electrically connected to the second dimming control unit 52 and configured to provide second dimming levels between 0% illumination and 100% illumination to the second diming control unit 52.
  • the second voltage drop sensor 54 or second current drop sensor is electrically connected to the backlight controller 42 and electrically connected between the first LED 22 and the second LED 24, said second voltage/current drop sensor 54 being configured to measure a second voltage drop value or a second current drop value through the first LED 22, 28 of each string 18, 20 and to provide the second voltage drop value or the second current drop value to the backlight controller 42.
  • the backlight unit 10 is able to behave in a fail safe mode such that minimum power consumption of the backlight unit 10 is reached.
  • a fail safe mode in the context of vehicle behavior, may be defined as a mode to prevent major failure of the vehicle when a device of the vehicle has a major failure.
  • the fail safe mode is a mode to save energy of the battery 38 when the battery voltage 36 of the vehicle becomes low such that some major functionalities of the vehicle may not operate in a nominal way.
  • a low battery voltage 36 of an electrical vehicle may reduce the remaining distance that may be traveled by the vehicle; a low battery voltage 36 of a vehicle may reduce the lighting power of the front and rear high/low beam.
  • the backlight unit 10 is limited on providing the operating output voltage 34 to only the first LED 22, 28 of each string 18, 20.
  • the first dimming levels are equal to 0%.
  • the second dimming levels are between 0% and 100%.
  • the backlight controller 42 may select the bypass topology 46 or the boost topology 44 of the power supply unit 14 such that the operating output voltage 34 is high enough to get the LEDs 22, 24, 26 of each string 18, 20 in conduction mode.
  • the backlight controller 42 is configured to determine the operating output voltage 34 from the current/voltage drop values and the second dimming levels such that said backlight controller 42 may select the boost topology 44 of the power supply unit 14 if the determined operating output voltage 34 is greater than the battery voltage value and may select the bypass topology 46 of the power supply unit 14 if the determined operating output voltage 34 is equal or lower than the battery voltage value.
  • the power supply unit 14 may comprise a buck topology 56 that provides an operating output voltage value lower that the battery voltage value.
  • the backlight controller 42 may be configured to select the buck topology 56 if the determined operating output voltage 34 is less than the battery voltage value instead of selecting the bypass topology 46.
  • the backlight controller 42 may diagnose the first LED 22, 28 of each string 18, 20, i.e. said backlight controller 42 may identify if the first LED 22, 28 of each string 18, 20 is damaged such that the first LED 22, 28 of each string 18, 20 is in short circuit mode or in open circuit mode. According to said diagnostic, the backlight controller 42 may adjust the second dimming levels, and/or selecting one of the bypass topology 46, the boost topology 44 and the buck topology 56 of the power supply unit 14 such that the operating output voltage 34 is just high enough to get the first LED 22, 28 of each string 18, 20 in conduction mode.
  • FIG. 3 illustrates a third embodiment.
  • Said third embodiment is an assembly of the embodiment of figure 2 with a warning indicator 58 of the vehicle 60.
  • the warning indicator 58 is configured to inform passengers of the vehicle 60 on the fail safe mode behavior.
  • the warning indicator 58 cooperates with at least one first LED 22 of a string 18 of the backlight module 12 such that the first LED 22 is switched ON during fail safe mode.
  • the first LED 22 illuminates the warning indicator 58 such that the second dimming control unit 52 controlling the illumination of only the first LED 22 of said string 18 is applying a second dimming level for said first LED 22 more than 0%.
  • the warning indicator 58 of the vehicle 60 is generally a dashboard warning light.
  • the warning indicator 58 is generally a red color dashboard warning light that informs the passenger of an important reminder that needs immediate attention.
  • the warning indicator 58 may also be a yellow (sometimes orange) dashboard warning light that usually means something needs to be repaired or serviced soon and to operate with caution. In our particular context, it may indicate the need of changing the battery 38 of the vehicle 60, or in the case of hybrid or electrical vehicle, the need to charge the battery of the electrical engine.
  • the warning indicator 58 may cooperate with other first LEDs 28 of other strings 20 of the backlight module 12.
  • the warning indicator 58 may cooperate with two first LEDs 22, 28 of two strings 18, 20 of the backlight module 12. That redundancy may prevent failures of one of the two LEDs 22, 28 such that the non-damaged first LED 22 may still illuminate the warning indicator.
  • the warning indicator 58 may be a combination of a left and a right turn indicator such that each turn indicator may cooperate with two first LEDs 22, 28.
  • the backlight controller 42 it may be possible to integrate inside the backlight controller 42 the first and/or the second dimming control unit 16, 52, and/or the first and/or the second voltage/current drop sensor 50, 54, and/or the battery voltage supervisor 48.
  • Figure 4 shows a method for controlling the backlight module 12 in the fail safe mode.
  • the first three steps are steps that may occur out of fail safe mode.
  • Said three first steps comprise providing 110 an operating output voltage 34 to the backlight module 12 from a battery voltage 36, controlling 112 first dimming levels of the illumination of the plurality of serials LEDs 22, 24, 26 of each string 18, 20 and controlling 114 second dimming levels illumination of only the first LED 22, 28 of each string 18, 20.
  • the last two steps may occur during a fails safe mode.
  • Said last two steps comprises providing 116 first dimming levels of 0% illumination of each LEDs 24, 26 ranked more than 1 of each string 18, 20 and providing 118 second dimming levels between 0% and 100% of each first LED 22, 28 of each string 18, 20.
  • Figure 5 shows a further refined and preferred method for controlling the backlight module 12 in the fail safe mode.
  • the five first steps 110, 112, 114, 116, 118 are similar steps and reference numerals as before.
  • the method comprises three steps wherein the backlight controller 42 is determining 120 the battery voltage value, is determining 122 a current drop or voltage drop value through the first LED 22, 28 of each string 18, 20, and is determining 124 an operating output voltage value from the determined current or voltage drop value and from the second diming levels.
  • the method comprises a step of selecting and operating 126 the boost topology 44 between the battery voltage 36 and the operating output voltage 34 if the determined operating output voltage value is greater than the battery voltage value, and a step of selecting and operating 128 a bypass topology between the battery voltage 36 and the operating output voltage 34 if the determined operating output voltage value is equal or lower than the battery voltage value.
  • the method may comprise a step of selecting and operating the buck topology 56 between the battery voltage 36 and the operating output voltage 34 if the determined operating output voltage value is lower than the battery voltage value instead of the bypass topology 46.
  • the method illustrated by figure 4 may be included in a method for backlighting the warning indicator 58 of the vehicle 60.
  • the method for backlighting the warning indicator 58 of the vehicle 60 comprises a step of backlighting the warning indicator with the first LED 22 of a first string 18.
  • a redundancy of illumination of the warning indicator 58 is needed such that the method for backlighting the warning indicator 58 of the vehicle 60 further comprises a step of backlighting the warning indicator 58 with the first LED 28 of the second string 20 of the plurality of serials LEDs 28, 29, 31 said plurality of serials LEDs 28, 29, 31 being ranked 1 to M from a first LED 28 to a last LED 31 in series.

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  • Circuit Arrangement For Electric Light Sources In General (AREA)
EP17201435.9A 2017-11-13 2017-11-13 Rückbeleuchtungseinheit und verfahren zur steuerung der rückbeleuchtung Withdrawn EP3484248A1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP17201435.9A EP3484248A1 (de) 2017-11-13 2017-11-13 Rückbeleuchtungseinheit und verfahren zur steuerung der rückbeleuchtung

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Application Number Priority Date Filing Date Title
EP17201435.9A EP3484248A1 (de) 2017-11-13 2017-11-13 Rückbeleuchtungseinheit und verfahren zur steuerung der rückbeleuchtung

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EP3484248A1 true EP3484248A1 (de) 2019-05-15

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022196371A1 (ja) * 2021-03-16 2022-09-22 ローム株式会社 発光素子駆動装置

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130049610A1 (en) * 2011-08-31 2013-02-28 Chia-Teh Chen Two-level led security light with motion sensor
US20160021713A1 (en) * 2008-11-17 2016-01-21 Express Imaging Systems, Llc Electronic control to regulate power for solid-state lighting and methods thereof
US9578701B1 (en) * 2016-05-12 2017-02-21 Infineon Technologies Ag Switched capacitor LED matrix driver

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160021713A1 (en) * 2008-11-17 2016-01-21 Express Imaging Systems, Llc Electronic control to regulate power for solid-state lighting and methods thereof
US20130049610A1 (en) * 2011-08-31 2013-02-28 Chia-Teh Chen Two-level led security light with motion sensor
US9578701B1 (en) * 2016-05-12 2017-02-21 Infineon Technologies Ag Switched capacitor LED matrix driver

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022196371A1 (ja) * 2021-03-16 2022-09-22 ローム株式会社 発光素子駆動装置

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