WO2013095055A1 - Module de rétroéclairage, procédé de commande de ce dernier et dispositif d'affichage qui utilise ce dernier - Google Patents

Module de rétroéclairage, procédé de commande de ce dernier et dispositif d'affichage qui utilise ce dernier Download PDF

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Publication number
WO2013095055A1
WO2013095055A1 PCT/KR2012/011289 KR2012011289W WO2013095055A1 WO 2013095055 A1 WO2013095055 A1 WO 2013095055A1 KR 2012011289 W KR2012011289 W KR 2012011289W WO 2013095055 A1 WO2013095055 A1 WO 2013095055A1
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WIPO (PCT)
Prior art keywords
voltage
backlight unit
power
power factor
current
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PCT/KR2012/011289
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English (en)
Korean (ko)
Inventor
정혜만
김오석
강현구
서일경
양영은
Original Assignee
서울반도체 주식회사
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Application filed by 서울반도체 주식회사 filed Critical 서울반도체 주식회사
Priority to US14/367,227 priority Critical patent/US20150154917A1/en
Priority claimed from KR1020120150621A external-priority patent/KR20130072175A/ko
Publication of WO2013095055A1 publication Critical patent/WO2013095055A1/fr

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    • 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
    • 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]
    • H05B45/20—Controlling the colour of the light
    • 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]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]
    • 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]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]
    • H05B45/38—Switched mode power supply [SMPS] using boost topology
    • 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

Definitions

  • the present invention relates to a backlight module, a method of driving the same, and a display device using the same. More specifically, the plurality of light emitting diodes of the backlight unit may be formed using a rectified voltage in the form of a pulse current and a power factor correction voltage having a DC component of a predetermined magnitude or more.
  • the present invention relates to a backlight module that can be driven efficiently, a driving method thereof, and a display device using the same.
  • the liquid crystal display device is the most widely used method, and since the liquid crystal panel does not emit light by itself, a light source called a backlight unit (BLU) is required on the back of the liquid crystal panel.
  • BLU backlight unit
  • the backlight unit Since the light generated from the backlight unit passes through the liquid crystal layer, the color filter, and the like, the backlight unit has a significant effect on the performance of the liquid crystal display (LCD) device. For example, not only the screen quality of the liquid crystal display device but also the weight, design, lifespan, power consumption, etc. can be significantly affected by the backlight unit.
  • LCD liquid crystal display
  • Recently used backlight module is composed of a backlight unit consisting of a plurality of LED (Light Emitting Diode) and a backlight unit driver for driving the backlight unit, the performance is determined according to the method of driving each LED backlight unit.
  • LED Light Emitting Diode
  • the backlight module used in the conventional liquid crystal display device drives a plurality of LEDs using a DC power supply.
  • the liquid crystal display device has a burden of adding a separate converter circuit for generating a DC power required to drive the LED.
  • the conventional liquid crystal display device needs to further include a separate converter for driving the backlight module in addition to the converter necessary for driving the display module, thereby increasing power consumption and increasing power loss in the converter. .
  • the present invention is to solve the above problems, the backlight module according to the present invention and a driving method and a display device using the same, the rectified voltage in the form of a pulse current to remove the DC-DC converter for supplying driving power to the backlight module
  • An object of the present invention is to efficiently drive a plurality of light emitting diodes of a backlight unit by using a power factor correction voltage having a DC component having a predetermined magnitude or more.
  • a backlight module, a method of driving the same, and a display device using the same include a ratio generated during multi-stage driving of an LED backlight unit using a rectified voltage in the form of a pulse current and a power factor correction voltage having a DC component of a predetermined magnitude or more. It is another object of the present invention to ensure stable driving of the device and to improve the reliability of the device by replenishing the insufficient energy when the current level rises by the dimming signal while the light emission period is removed.
  • a backlight module, a driving method thereof, and a display device using the same may be manufactured by removing a DC-DC converter used to supply driving power of an LED backlight unit of a liquid crystal display device. Reducing costs is another purpose.
  • a display device includes a power rectifier for rectifying AC power to output a rectified voltage; A power factor correction unit configured to receive the rectified voltage from the power rectifier and compensate the power factor of the AC power and output a power factor correction voltage including at least a predetermined DC voltage component; A display module driven by the power factor correction voltage; A backlight unit having a plurality of light emitting diodes for providing backlight illumination to the display module; And receiving the rectified voltage to generate the main driving voltage or the main driving current, and supply the main driving voltage or the main driving current to the backlight unit, and receiving the power factor correction voltage when the magnitude of the rectifying voltage is smaller than a preset threshold to compensate the driving. And a backlight unit driver configured to generate a voltage or supplemental drive current, and supply the generated supplemental drive voltage or supplemental drive current to the backlight unit.
  • the backlight unit driver may include a supplementary driving voltage or a supplementary driving current when the magnitude of the main driving voltage from the rectified voltage is smaller than the minimum voltage for driving the at least one light emitting diode. It is characterized by supplying to the backlight unit.
  • the display module may generate a dimming signal for controlling the backlight unit driver to generate a set dimming voltage or a set dimming current.
  • the backlight unit driver supplies the supplementary driving voltage to the backlight unit when the main driving voltage is less than the set dimming voltage, or the supplementary driving current to the backlight unit when the main driving current is less than the set dimming current. It is characterized by the supply.
  • a display apparatus includes: a first wire connecting an output terminal of a power rectifying unit and a first input terminal of a backlight unit driving unit and transferring a rectified voltage from the power rectifying unit to the backlight unit driving unit; And a second wiring connecting the output terminal of the power factor compensator to the second input terminal of the backlight unit driver and transferring the power factor correction voltage from the power factor compensator to the backlight unit driver.
  • the backlight unit driver emits light among the plurality of light emitting diodes as the magnitude of the rectified voltage increases based on the rectified voltage whose voltage varies periodically over time. As the number of s increases and the magnitude of the rectified voltage decreases, the backlight unit is controlled to reduce the number of light emitting diodes emitting light among the plurality of light emitting diodes.
  • the backlight unit driving unit is connected between the output terminal of the plurality of LED groups each including at least one light emitting diode of the plurality of light emitting diodes, and the reference potential, respectively.
  • a plurality of current controllers forming a current path between an output terminal of each LED group and a reference potential according to a control signal;
  • a control signal generator for applying a control signal for controlling the operations of the plurality of current controllers to the plurality of current controllers according to the magnitude of the main driving voltage.
  • the backlight unit driver is disposed between an output terminal of the power factor correction unit and an input terminal of the backlight unit, and further includes a voltage compensator for controlling supply of the power factor correction voltage to the backlight unit. Characterized in that.
  • the voltage compensator includes: a switching element having a first terminal connected to an output terminal of the power factor compensator; And a diode having an anode connected to the second terminal of the switching element and a cathode connected to the input terminal of the backlight unit.
  • the switching element is characterized in that the on or off operation by the control signal of the control signal generator.
  • the backlight unit driving unit when the magnitude of the rectified voltage is less than the minimum voltage for driving at least one LED group of the plurality of LED groups to the control unit to the voltage compensation unit It is characterized by supplying a supplementary drive voltage or supplemental drive current by the power factor correction voltage to the plurality of LED groups.
  • the backlight unit driver when a dimming signal for controlling the backlight unit driver to generate the set dimming voltage or the set dimming current is received from the display module, the backlight unit driver is configured such that the main driving voltage is set dimming.
  • the supplementary driving voltage is supplied to the backlight unit when the voltage is smaller than the voltage, or the supplementary driving current is supplied to the backlight unit when the main driving current is smaller than the set dimming current.
  • the power rectifier includes: a first power rectifier disposed at an input terminal of the power factor corrector and configured to supply a rectified voltage rectified by AC power to the power factor corrector; And a second power rectifying unit provided in the backlight unit driving unit and supplying a rectified voltage obtained by rectifying AC power to the backlight unit.
  • the power factor correction unit includes: an inductor having a first terminal connected to a high potential first terminal of an input capacitor connected in series with an output terminal of a power rectifier; A switch having a first terminal connected to the second terminal of the inductor, and a second terminal connected to the low potential second terminal of the input capacitor; A diode having an anode commonly coupled to a second terminal of the inductor and a first terminal of the switch, and a cathode coupled to the high potential first terminal of the output capacitor; And an output capacitor having a first terminal connected to the cathode of the diode, and a second terminal commonly connected with the second terminal side of the low potential side of the input capacitor and the second terminal side of the switch.
  • the power factor correction unit has an interleaved boost converter type in which two power factor correction units each including an inductor, a switch, a diode, and an output capacitor are connected in parallel to each other. It is done.
  • At least one of the power rectifier and the power factor correction unit is disposed in the form of a single integrated circuit with the backlight unit driver.
  • the backlight module comprises: a power factor correction unit configured to output a power factor correction power by compensating a power factor of an AC power source; A backlight unit including a plurality of light emitting diodes; And a backlight unit driver configured to drive the plurality of light emitting diodes according to the dimming signal.
  • the backlight unit driver may be configured to selectively supply the AC power and the power factor correction power to the plurality of light emitting diodes according to the dimming signal and the magnitude of the AC power.
  • the backlight unit includes a plurality of light emitting diodes connected in series
  • the backlight unit driving unit includes: a power rectifying unit rectifying AC power to supply a rectified voltage to the backlight unit; A plurality of current controllers connected between one terminal of the light emitting diode (cathode) and the reference potential and forming a current path between the light emitting diode and the reference potential according to a control signal; And a control signal generator configured to generate a control signal for controlling the operations of the plurality of current controllers according to the dimming signal and the magnitude of the rectified voltage.
  • control signal generation unit may adjust the current value flowing through the backlight unit by controlling the operation state of the current controller according to the level of the dimming signal.
  • the backlight module according to another embodiment of the present invention may further include a voltage compensator for supplying a voltage output from the power factor compensator to the backlight unit according to the magnitude of the rectified voltage and the level of the dimming signal.
  • the voltage compensator supplies a voltage output from the power factor compensator to the backlight unit during a period where the rectified voltage is less than or equal to the threshold.
  • the voltage compensator includes a switching device that performs a switching operation according to a compensation control signal generated based on a dimming signal during a period where the rectified voltage is less than or equal to a threshold value.
  • the switching element is characterized in that for connecting the output terminal of the power factor correction unit to the backlight unit according to the compensation control signal.
  • the voltage compensator further comprises a diode in which one terminal of the switching element and the anode are connected in series.
  • the other terminal of the switching element is connected to the output terminal of the power factor correction unit, and the cathode of the diode is connected to the node connected to the input terminal of the backlight unit and the power rectifier.
  • the backlight unit is driven by a backlight unit driver for driving a backlight unit including a plurality of light emitting diode (LED) groups each having at least one light emitting diode to provide lighting to a display module.
  • a backlight unit driver for driving a backlight unit including a plurality of light emitting diode (LED) groups each having at least one light emitting diode to provide lighting to a display module.
  • LED light emitting diode
  • a method of driving a module comprising: a first step of rectifying an AC power source to generate a rectified voltage; Compensating the power factor of the AC power supply to generate a power factor correction voltage including a DC voltage component having at least a predetermined magnitude; Receiving a rectified voltage to generate a main driving voltage or a main driving current, and supplying the main driving voltage or the main driving current to the backlight unit; And supplying a supplementary driving voltage or supplementary driving current by the power factor correction voltage to the backlight unit when the magnitude of the rectified voltage is smaller than a preset threshold.
  • the third step is to emit light among the plurality of LED groups as the magnitude of the rectified voltage increases based on the rectified voltage whose voltage varies periodically with time.
  • the operation of the backlight unit is controlled to increase the number of LED groups, and the operation of the backlight unit is controlled to reduce the number of LED groups emitting light among the plurality of LED groups as the size of the rectified voltage decreases.
  • the fourth step may include a power factor correction voltage when the magnitude of the rectified voltage is smaller than a minimum voltage for driving at least one LED group among the plurality of LED groups.
  • the supplementary driving voltage or supplementary driving current is supplied to the plurality of LED groups.
  • the driving method of the backlight module further includes, before the fourth step, receiving a dimming signal from the display module for controlling the backlight unit driver to generate a set dimming voltage or a set dimming current. It is characterized by.
  • the fourth step may be characterized in that the supplementary driving voltage is supplied to the backlight unit when the main driving voltage is smaller than the set dimming voltage, or the supplementary driving current is supplied to the backlight unit when the main driving current is smaller than the set dimming current. .
  • the backlight module, the driving method thereof, and the display device using the same remove a DC-DC converter for supplying driving power to the backlight module, and provide a rectified voltage in the form of a pulse current and a DC component of a predetermined size or more.
  • the excitation power factor compensation voltage is used to efficiently drive a plurality of LEDs of the backlight unit.
  • a backlight module, a method of driving the same, and a display device using the same include a ratio generated during multi-stage driving of an LED backlight unit using a rectified voltage in the form of a pulse current and a power factor correction voltage having a DC component of a predetermined magnitude or more.
  • a backlight module, a driving method thereof, and a display device using the same may be manufactured by removing a DC-DC converter used to supply driving power of an LED backlight unit of a liquid crystal display device. It provides the effect of reducing costs.
  • FIG. 1 is a schematic block diagram of a display device according to the present invention.
  • FIG. 2 is a circuit diagram of an AC-DC converter employable in the display device of FIG. 1.
  • FIG. 2 is a circuit diagram of an AC-DC converter employable in the display device of FIG. 1.
  • FIG. 3 is a block diagram of a backlight module employable in the display device of FIG.
  • FIG. 4 is a waveform diagram illustrating an operating principle of a backlight module of the display device of FIG. 1.
  • 5 and 6 are waveform diagrams for explaining the dimming principle that can be employed in the display device of FIG.
  • FIG. 7 is a schematic block diagram of a display device according to an embodiment of the present invention.
  • FIG. 8 is a circuit diagram of an AC-DC converter employable in the display device of FIG.
  • FIG. 9 is a block diagram illustrating a power supply device of a display device according to another embodiment of the present invention.
  • FIG. 10 is a block diagram of a backlight module employable in the display device of FIG. 9.
  • FIG. 10 is a block diagram of a backlight module employable in the display device of FIG. 9.
  • FIG. 11 is a waveform diagram illustrating an operating principle of the display device of FIG. 9.
  • FIG. 11 is a waveform diagram illustrating an operating principle of the display device of FIG. 9.
  • FIG. 12 is a flowchart illustrating a method of driving a backlight module according to the present invention.
  • FIG. 1 is a schematic block diagram of a display device according to the present invention.
  • a display apparatus includes a display module 101, a power rectifier 102, a power factor corrector 104, a backlight unit 120, and a backlight unit driver 130.
  • the power current unit 102 and the power factor correction unit 104 may correspond to the AC-DC converter 101a disposed at the power input terminal of the display device to convert AC power into DC power.
  • the backlight unit 120 and the backlight unit driver 130 may correspond to a backlight module that provides illumination to the screen display unit of the display module 101.
  • the backlight module 140 receives the rectified power including the rectified voltage V REC from the AC-DC converter 101a, and receives the power factor correction voltage from the AC-DC converter 101a.
  • the main characteristic is to receive the power factor correction power supply including V PFC and to remove the non-light emitting period in the multi-stage driving type backlight unit 120 using the received rectification power factor and the power factor correction power source.
  • the rectified power including the rectified voltage V REC is connected to the backlight unit at the power rectifying unit 102 through the first wiring 105a connecting the output terminal of the power rectifying unit 102 and the first input terminal of the backlight unit driver 130. It may be supplied to the driver 130.
  • the power factor correction power supply including the power factor correction voltage V PFC is connected to the power factor correction unit 104 through a second wiring 105b connecting the output terminal of the power factor correction unit 104 and the second input terminal of the backlight unit driver 130. ) May be supplied to the backlight unit driver 130.
  • the first wiring 105a and the second wiring 105b may be implemented by a power cable, a conductive pattern of an integrated device, or the like.
  • the backlight module 140 according to the present invention drives the backlight unit 120 including the plurality of LED groups in a multi-stage driving scheme
  • the non-light emission period accompanying the multi-stage driving scheme is performed using a power factor correction voltage.
  • the backlight module 140 removes the non-light emitting period generated when the backlight unit of the conventional multi-stage driving method is driven so that the backlight unit 120 flickers while driving, or the luminance thereof is changed by the user. You can prevent it from shaking so hard that you can feel it easily.
  • the backlight module 140 may have a predetermined voltage Va or a predetermined signal for driving and controlling the backlight module from the display module 101 connected to the user of the display apparatus through a predetermined user interface. It can be implemented to receive.
  • FIG. 2 is a circuit diagram of an AC-DC converter employable in the display device of FIG. 1.
  • the AC-DC converter 101a includes a first filter 102a, a power rectifier 102, a second filter 102b, an input capacitor Cin, and a power factor corrector ( 104).
  • the first filter 102a may be an electromagnetic interference (EMI) filter disposed at an input terminal of the power rectifier 102.
  • the EMI filter operates to reduce the noise signal on the input AC power supply during normal operation of the display device or AC-DC converter 101a and to reduce the magnitude of the surge pulse during abnormal operation.
  • Such an EMI filter may be implemented with a common mode choke capable of reducing noise on both power lines of an input AC power supply, and two capacitors C1 and C2 connected to both ends of the common mode choke. .
  • the power rectifying unit 102 is for rectifying the input AC power, and may be implemented as a bridge diode that full-wave rectifies the input AC power by four diodes.
  • the second filter 102b may be an LC filter by the capacitor C and the inductor L disposed at the output terminal of the power rectifier 102.
  • a resonant circuit is formed by a combination of a capacitor C through high frequency current and an inductor L through high frequency current, and the display device or AC The high frequency noise at the power input terminal of the DC converter 101a can be selectively removed.
  • the input capacitor Cin is disposed at the output end of the second filter 102b, that is, at the output end of the power rectifier 102, and operates to stabilize the rectified power applied to the power factor corrector 104.
  • the high potential side output terminal of the power rectifier 102 to which the first terminal of the input capacitor Cin is connected and the inductor L of the second filter 102b is connected is the AC-DC converter 101a of the display device. ) Corresponds to the first output terminal for outputting the rectified voltage V REC .
  • the power factor correction unit 104 compensates for the power factor of the input AC power source based on the rectified power supply from the power supply rectifier, and includes an inductor L1, a switch S1, a diode D1, and an output capacitor ( It can be implemented as an active power factor correction circuit having a Cout).
  • the inductor L1 includes a first terminal commonly connected to the first terminal of the input capacitor Cin and the high potential output terminal of the power rectifier 102.
  • the switch S1 comprises a field effect transistor having a first terminal, a second terminal, and a control terminal, etc., wherein the first terminal is connected to the second terminal of the inductor L1, and the second terminal is connected to the resistor R1. And are commonly connected to the second terminal and the reference potential of the input capacitor Cin.
  • the control signal SC6 from a predetermined power factor correction (PFC) controller is applied to the control terminal of the switch S1.
  • the PFC controller may be implemented as at least some functional units of the backlight unit driver of the backlight module (see 140 of FIG. 1) or at least some components of the backlight unit driver that performs functions corresponding to the functional units.
  • the anode of the diode D1 is commonly connected to the second terminal of the inductor L1 and the first terminal of the switch S1, and the cathode thereof is formed of the output capacitor Cout. 1 terminal is connected.
  • the second terminal of the output capacitor Cout is commonly connected to the low potential side output terminal of the power rectifier 102, the second terminal of the input capacitor Cin, and the second terminal of the switch S1.
  • the node to which the cathode of the diode D1 of the power factor correction unit 104 and the first terminal of the output capacitor Cout are connected is connected to the power factor correction voltage V PFC in the AC-DC converter 101a of the display device.
  • the power factor correction unit 104 When operating in the discontinuous current mode (DCM), the power factor correction unit 104 is turned on when the current flowing in the inductor L1 is zero, and is a voltage applied across the resistor R1 as a comparator.
  • the operation of the switch S1 may be controlled to be turned off when the voltage applied to the negative input terminal and the rectifier voltage applied to the positive input terminal are the same according to the current flowing through the inductor L1.
  • the power factor correction unit 104 can substantially make the power factor close to 1 by causing the average waveform of the current (corresponding to the rectified current) output from the power supply rectifier 102 to follow the waveform of the rectified voltage.
  • the conventional backlight module in order to minimize the ripple of the output voltage in the power factor correction circuit, it is common to consider a specific specification (low ESR capacitor, etc.) of the output capacitor. Since the rectified voltage and the power factor correction voltage are used as they are, the degree of freedom in design can be increased by increasing the selection range of the output capacitor of the power factor correction unit as compared to the conventional power factor correction circuit.
  • the AC-DC converter 101a may be disposed at an input terminal of the backlight unit 120 according to an implementation, and may include a ripple remover (not shown) to remove ripple of driving power supplied to the backlight unit 120. May be provided).
  • the ripple removing unit may be included as a part of the backlight unit driver 130, or may be included as a part of the backlight module 140 including the backlight unit driver 130 and the backlight unit 120.
  • the ripple remover removes at least a part of the AC component included in the power factor correction voltage V PFC provided from the power factor correction unit 104, and then provides the power factor compensation voltage to which the AC component is partially removed to the backlight unit 120. If the ripple cancellation unit is used, the size of the AC component included in the power factor correction voltage is too large to reduce the power consumption by the ripple component, thereby facilitating the driving of the backlight unit 120. can do.
  • FIG. 3 is a block diagram of a backlight module employable in the display device of FIG. 1.
  • the backlight module 140 includes a backlight unit 120 and a backlight unit driver 130.
  • the backlight unit driver 130 includes a plurality of current controllers 131 to 134, a control signal generator 135, and a voltage compensator 138.
  • each LED group has at least one light emitting diode.
  • Each LED group may have a plurality of light emitting diodes connected in series with each other.
  • each of the plurality of current controllers 131 to 134 includes a switching element (not shown) and a feedback resistor (not shown).
  • the switching element is connected between the output terminal (corresponding to the cathode side of the light emitting diode) of each LED group and one end of the feedback resistor, and is selectively turned on in accordance with the switching control signals SC1 to SC4.
  • the switching element may be a semiconductor switch such as a field effect transistor (FET), and controls the magnitude of the current flowing through each LED group by the switching control signal.
  • FET field effect transistor
  • the other end of the feedback resistor may be connected to a reference potential or ground.
  • the control signal generator 135 generates the switching control signals SC1 to SC4 and the compensating switching control signal SC5 according to the rectified voltage V REC in which the magnitude of the voltage fluctuates periodically, and generates the current by the generated control signal.
  • the controllers 131 to 134 and the voltage compensator 138 are provided.
  • control signal generator 135 detects a current flowing through each of the light emitting diodes 122, 124, 126, and 128 through the current controllers 131 ⁇ 134, and detects a current or a voltage corresponding to the current. Is compared with a preset reference value, and the switching control signals SC1 to SC4 are generated according to the comparison result. In addition, the control signal generator 135 compares the rectified voltage V REC with a reference value and generates the compensation switching control signal SC5 according to the comparison result.
  • the preset reference value is a voltage level corresponding to the minimum emission reference of the backlight unit 120 and a forward voltage (Vf) level of any one of the plurality of light emitting diodes 122, 124, 126, and 128. It can be set based on either.
  • the voltage compensator 138 selectively supplies the power factor correction power supply (V PFC, etc.) to the backlight unit 120 according to the compensation switching control signal SC5.
  • the voltage compensator 138 may be formed as a series circuit of the switching element SW5 and the diode D5 connected between the output terminal of the power factor compensator 104 and the input terminal of the backlight unit 120.
  • the switching element SW5 may be implemented as a field effect transistor having a first terminal, a second terminal, and a control terminal, and the first terminal is connected to the output terminal of the power factor correction unit, and the second terminal is connected to the diode D5. It is connected to the anode and is selectively turned on according to the compensation switching control signal SC5.
  • the cathode of the diode D5 is commonly connected to the output terminal side of the power rectifier and the input terminal of the backlight unit 120. The diode D5 prevents the rectified power supply V REC from flowing back to the power factor correction unit 104 when the switching element SW5 is turned off.
  • the backlight unit 120 includes one or more LED arrays in which a plurality of LED groups 122 to 128 each having at least one LED element are connected in series.
  • the backlight unit 120 performs the multi-stage driving in the form of adjusting the lighting state of the light emitting diode according to the degree of the rising or falling of the voltage of the AC power source or the rectifying power source by the current control of the backlight unit driver 130.
  • the backlight unit 120 may drive in multiple stages such that the number of LED groups emitting from the LED array increases as the size of the rectified voltage increases, and the number of LED groups emitting from the LED array decreases as the size of the rectified voltage decreases.
  • the backlight unit 120 operates to receive at least one LED group by receiving the power factor correction voltage from the power factor correction unit in the non-light emitting period generated during the multi-stage driving so that the non-light emitting period is not formed during the multi-stage driving.
  • the non-light emitting period refers to a period in which the magnitude of the rectified voltage is smaller than the forward voltage of one LED group.
  • the conventional backlight unit may cause a flicker phenomenon during multi-stage driving, but the backlight module of the present invention uses a power factor correction voltage to eliminate the non-light emitting period that causes the flickering problem. To improve.
  • the backlight unit 120 is illustrated as having four LED groups 122, 124, 126, and 128 each represented by one light emitting diode.
  • the number of light emitting diodes or the number of LED groups included in each LED group, the number of current controllers and their specific configurations may be changed in various forms.
  • the backlight unit 120 may include two or more LED groups connected in series or may include a plurality of LED groups connected in series or in parallel.
  • FIG. 4 is a waveform diagram illustrating an operating principle of a backlight module of the display apparatus of FIG. 1.
  • the backlight module of the display device includes a backlight unit 120 having a plurality of LED groups 122, 124, 126, and 128, current controllers 131 to 134, A case in which the control signal generator 135 and the voltage compensator 138 are provided and the forward voltages of the plurality of LED groups 122, 124, 126, and 128 are all predetermined voltages Vf will be described.
  • Each LED group of the plurality of LED groups is referred to as a first LED group 122, a second LED group 124, a third LED group 126, and a fourth LED group 128 in the order described, and each LED
  • the current controllers connected to the output terminals of the group are referred to as a first current controller 131, a second current controller 132, a third current controller 133, and a fourth current controller 134, respectively.
  • the switching elements of each of the current controllers 131 to 134 maintain a turn-on state, and the switching element SW5 of the voltage compensator 138 maintains a turn-off state.
  • the rectified voltage V REC is applied to the backlight module and the rectified voltage becomes equal to or greater than the first voltage Vf1 at a predetermined time t0
  • the first LED group 122 and the first current controller 131 When the rectified voltage V REC is applied to the backlight module and the rectified voltage becomes equal to or greater than the first voltage Vf1 at a predetermined time t0, the first LED group 122 and the first current controller 131.
  • the current path (Path) through the () is formed so that the first LED group 122 emits light.
  • the first current controller 131 controls the magnitude of the current flowing in the first LED group 122 according to a preset current level based on the first voltage Vf1.
  • the backlight module may be set to supply the power factor correction voltage V PFC to the backlight unit 120 when the rectified voltage V REC is smaller than the first voltage Vf1, in which case, according to the present embodiment
  • the backlight module 140 backlights the power factor correction current I PFC of the level set by the first current controller 131 during the hatched period from a certain time point before the predetermined time point t0 to the predetermined time point t0. Supply to unit 120.
  • the control signal generator 135 turns off the switching element of the first current controller 131. Then, a current path through the two LED groups 122 and 124 and the second current controller 132 is formed, and the two LED groups 122 and 124 emit light. In this case, the second current controller 132 controls the magnitude of the current I REC flowing through the two LED groups 122 and 124 in response to the magnitude of the rectified voltage.
  • the control signal generator 135 switches the switching element and the second current controller 132 of the first current controller 131. Turn off the switching element. Then, a current path is formed through the three LED groups 122, 124, and 126 and the third current controller 133, and the three LED groups 122, 124, and 126 emit light.
  • the third current controller 133 controls the magnitude of the current I REC flowing through the three LED groups 122, 124, and 126 in response to the magnitude of the rectified voltage.
  • the control signal generator 135 controls the switching elements of the first to third current controllers 131, 132, and 133. Turn off. Then, a current path is formed through the four LED groups 122, 124, 126, and 128 and the fourth current controller 134, and the four LED groups 122, 124, 126, and 128 emit light. In this case, the fourth current controller 134 controls the magnitude of the current I REC flowing through the four LED groups 122, 124, 126, and 128 in response to the magnitude of the rectified voltage.
  • control signal generator 135 multi-stages the plurality of LED groups 122, 124, 126, and 128 so that the number of LED groups emitting from the backlight unit 120 increases as the size of the rectified voltage increases. Drive it.
  • the control signal generator 135 turns off the LED group in the reverse order when the rectified voltage rises. That is, when the rectified voltage is lower than the fourth voltage Vf4 at the fourth time point t4, the control signal generator 135 drives the third current controller 133 to display the three LED groups 122, 124, and 126. And a current path passing through the third current controller 133, thereby causing the three LED groups 122, 124, and 126 to emit light.
  • the control signal generator 135 drives the second current controller 132 to drive the two LED groups 122 and 124 and the second current.
  • a current path is formed through the control unit 132, thereby causing the two LED groups 122 and 124 to emit light.
  • the control signal generator 135 drives the first current controller 131 to drive the first LED group 122 and the first LED.
  • the first LED group 122 emits light by forming a current path through the current controller 131.
  • the control signal generator 135 may determine the voltage compensator 138 at the seventh time point t7. Turns on the switching element SW5.
  • the control signal generator 135 may be connected to the seventh time point t7.
  • the power factor correction current I PFC may be supplied to the first LED group 122 through a current path through the first LED group 122 and the second current controller 131 during the period of the eighth time point t8.
  • the interval between the seventh time point t7 and the eighth time point t8 corresponds to the non-light emitting period when the power factor correction voltage V PFC is not supplied to the backlight unit 120 (comparative example).
  • the control signal generator 135 may generate a voltage compensator at the eighth time point t8.
  • the switching element SW5 of 138 is turned off.
  • the backlight module 140 supplies the power factor correction voltage V PFC to the backlight unit 120 when the rectified voltage V REC is smaller than the first voltage Vf1.
  • the power factor correction current I PFC of a level preset by the first current controller 131 may be supplied to the backlight unit 120 in the hatched section (t7-t8, etc.), thereby removing the existing non-light emitting section. can do.
  • the rectified voltage V REC corresponds to the driving voltage V LED of the backlight unit 120, and the rectified current I REC and the power factor correction voltage V PFC by the rectified voltage V REC .
  • the driving current I LED of the backlight unit 120 in combination with the power factor correction current I PFC .
  • the backlight module may receive a predetermined voltage Va or a predetermined signal from the display module 101 (refer to 101 of FIG. 1) to control brightness of the backlight unit 120.
  • the predetermined voltage Va may be a reference voltage and the predetermined signal may be a dimming signal.
  • the following describes the operation principle of the backlight module when the backlight module receives a dimming signal (see V DIMM of FIG. 10) from the signal processor of the display module. For convenience of description, it is assumed that the dimming signal is received during the multi-stage driving of the backlight module described above with reference to FIG. 4.
  • 5 and 6 are waveform diagrams for describing a dimming principle that can be employed in the display device of FIG. 1.
  • the dimming signal maintains a voltage level corresponding to the minimum light emission reference of the backlight unit 120, for example, a luminance level corresponding to the first voltage Vf1 regardless of a change in brightness of an image signal, will be described. As follows.
  • the backlight unit driving unit corresponds to a driving current corresponding to the voltage level (eg, the first voltage) designated by the dimming signal. (I LED ) is operated to be supplied to the backlight unit 120.
  • the conventional multi-stage driving unit of the backlight unit generates a non-emitting section corresponding to the hatched section during the dimming operation.
  • the backlight module according to the present exemplary embodiment has a hatched section (P1, etc.) corresponding to the non-emitting section.
  • the backlight unit of the conventional multi-stage driving method generates a non-light emitting period corresponding to the hatched division during the dimming operation due to the lack of driving energy due to the characteristics of the multi-stage driving method
  • the backlight module according to the present embodiment is a hatched section ( According to the operation of the fourth current controller 134 in P2, the power factor correction current corresponding to the level of the dimming signal may be supplied to the backlight unit so that the non-light emitting period may not occur in the backlight unit during the dimming operation.
  • the non-emission period may be prevented from occurring in the backlight unit 120 using the power factor correction voltage V PFC .
  • the backlight unit 120 dimmes by supplementing energy to the backlight unit by using the power factor correction voltage output from the power factor correction unit 104 during a period corresponding to the existing non-light emitting period. It can be operated normally at high level of signal.
  • the conventional non-light emitting section formed during driving according to the dimming signal in the backlight module of the multi-stage driving method can be removed, but the present invention is not limited to such a configuration.
  • the number of LEDs to be lit or the level of voltage to be compensated for may be changed according to a user's selection according to a reference brightness, a reference brightness required when driving the backlight unit 120.
  • the waveform diagrams shown in FIGS. 5 and 6 are examples, and the number of LED groups turned on, the turn-on timing, etc. may be variously changed according to the configuration of the current controller.
  • a separate converter must be used to generate a DC power source for driving the backlight module.
  • the backlight module and the display device using the same according to the present invention omit a DC-DC converter for the backlight unit.
  • the backlight unit can be directly driven by an AC power supply, thereby miniaturizing the device and reducing manufacturing cost.
  • FIG. 7 is a schematic block diagram of a display apparatus according to an embodiment of the present invention.
  • the display device includes a power rectifier 102, a power factor correction unit 104, a converter 106, a signal processor 110, a display driver 112, and a screen display 114. And a backlight module 140A.
  • the converter 106, the signal processor 110, the display driver 112, and the screen display 114 may correspond to the display module 101 of FIG. 1.
  • the display device according to the present embodiment may further include a filter at an input terminal or an output terminal of the power rectifying unit 102 according to the implementation.
  • the power rectifier 102 rectifies and supplies the AC power to the power factor correction unit 104.
  • the power rectifying unit 102 may be implemented as a bridge diode for full-wave rectifying the sinusoidal AC power.
  • the power factor correction unit 104 outputs the power factor correction power by compensating the power factor of the AC power supply 10 based on the rectified power output from the power rectifier 102.
  • the power factor correction power source has a DC voltage level. For example, when the AC power source 10 is 220V, the power factor correction power source may have a voltage magnitude of about 380 to 420V.
  • the power factor correction unit 104 may be implemented using a plurality of passive elements or active elements. For example, it may include an active power factor correction circuit in the form of a boost converter.
  • the converter 106 receives the power factor correction power to generate a DC power having a level required to drive the signal processor 110 and the display driver 112.
  • the DC power output from the converter 106 may be used to drive various processors included in the signal processor 110.
  • the DC power is supplied to the gate line or the data line of the screen display unit 114 through the display driver 112, whereby a predetermined image is displayed on the screen display unit.
  • the signal processor 110 generates various control signals by processing various image signals input from the outside, and supplies the generated control signals to the display driver 112. For example, the signal processor 110 processes an image signal to generate a control signal for controlling a voltage to be applied to a data line of the screen display 114, or generates a control signal for controlling a voltage to be applied to a gate line. .
  • the signal processor 110 generates a control signal (hereinafter, referred to as a dimming signal) for controlling the brightness and the on / off timing of the backlight unit 120 and supplies it to the backlight unit driver 130.
  • a dimming signal may include a signal required for local dimming when the backlight unit 120 includes a local dimming structure in which brightness is controlled for each region.
  • the display driver 112 drives the screen display unit 114 according to the output of the signal processor 110.
  • the display driver 112 includes a gate driver connected to a pixel of the screen display 114 through a gate line, a data driver connected to a pixel through a data line, a timing controller that controls operation timings of the gate driver and the data driver. can do.
  • the screen display unit 114 includes a plurality of pixels arranged in a matrix so as to output a predetermined image according to an image signal.
  • the plurality of pixels may include a liquid crystal capable of adjusting the amount of light transmitted by illumination of the backlight unit 120, an electrode for controlling the liquid crystal, a color filter for expressing color, and the like.
  • the backlight module 140 includes a backlight unit 120 that provides illumination to the screen display unit 114, and a backlight unit driver 130 that drives the backlight unit 120.
  • the backlight unit driver 130 receives the rectified power and the power factor correction power, and controls the operation of the backlight unit 120 according to a preset control signal or a dimming signal from the signal processor 110.
  • the backlight module 140 In the backlight module 140 according to the present exemplary embodiment, a method of using the power factor correction power source so that a non-light emitting period does not occur while driving the backlight unit has been described with reference to FIGS. 1 to 6. Detailed description is omitted.
  • the power rectifier 102 and the power factor corrector 104 may be implemented as a single AC-DC converter that compensates for the power factor of the AC power and outputs the power factor correction power.
  • the power rectifier 102, the power factor correction unit 104, and the backlight unit driver 130 may be implemented as a single integrated circuit 130A for driving a backlight having a power factor correction function.
  • the backlight module 140A corresponds to the one provided with the backlight unit driver having the power factor correction function.
  • the backlight unit driver having the power factor correction function includes the power factor corrector 104 but does not include the power rectifier 102 or the power rectifier 102 but does not include the power factor corrector 104. It may be implemented in the form of a single integrated circuit.
  • FIG. 8 is a circuit diagram of an AC-DC converter employable in the display device of FIG. 7.
  • the AC-DC converter 101b of the display apparatus according to the present exemplary embodiment has an interleaved boost converter type in which two boost converters are connected in parallel.
  • the AC-DC converter 101b of the present embodiment is a parallel connection of two AC-DC converters 101a described above with reference to FIG. 3.
  • the inductor L2, the switch S2, and the resistor ( Since R2) and diode D2 and their coupling relationship are substantially the same as the corresponding components of AC-DC converter 101a and their coupling relationship, detailed description thereof will be omitted to avoid duplication of explanation.
  • the input voltage corresponding to the voltage across the input capacitor Cin and the output voltage corresponding to the voltage across the output capacitor Cout are approximately half.
  • the volume and capacity of the capacitors C1 and C2 and the inductors L1 and L2 can be made smaller than in the case of the AC-DC converter 101a in the form of a single boost converter to meet the thinning of the flat panel display device.
  • the current flowing through the AC-DC converter 101b may be reduced to increase power efficiency by lowering power loss.
  • FIG. 9 is a block diagram illustrating a power supply apparatus of a display apparatus according to another embodiment of the present invention.
  • the power supply device 130B of the display device may include a filter 102a, a power rectifier 102, a power factor corrector 104, a first DC-DC converter 106a, A second DC-DC converter 106b, a Temporary OverVoltage (TOV) generator 107, and a backlight unit driver 130A are provided.
  • the power supply device 130B has a switch mode power supply having a power factor correction function and a backlight unit driving function.
  • the first DC-DC converter 106a corresponds to the standby power DC-DC converter
  • the second DC-DC converter 106b corresponds to the module power DC-DC converter of the display module.
  • the second DC-DC converter 106b corresponds to a converter for supplying the module driving power supply Vout2 to the PMIC (Power Management Integrated Circuit) of the display module
  • the first DC-DC converter 106a corresponds to the display device.
  • the display device may correspond to a converter supplying standby power Vout1 separated from the second DC-DC converter 106b to operate only the minimum standby power.
  • the first and second DC-DC converters 106a and 106b may have a form integrated into one DC-DC converter.
  • the backlight unit driver 130A which belongs to the backlight module, rectifies AC power input through the wiring 105c connected to the input terminal of the power rectifier 102 to generate rectified power.
  • Another power rectifier may be provided to supply the generated rectified power to the backlight unit.
  • the backlight unit driver 130A disposed in the power supply device 130B of the present embodiment not only controls the non-light emitting period in the backlight unit by using the power factor correction voltage V PFC but also controls the backlight unit.
  • Increasing the driving voltage by a predetermined basic voltage TOV allows the plurality of LED groups of the backlight unit to drive a high voltage, thereby increasing efficiency due to high voltage and low current driving.
  • the high voltage means a voltage higher than the maximum value of the AC voltage V AC or the rectified voltage V REC of the input AC power source 10.
  • FIG. 10 is a block diagram of a backlight module employable in the display apparatus of FIG. 9.
  • the backlight module 140A includes a backlight unit 120 and a backlight unit driver 130A disposed in an SMPS type power supply device 130B.
  • the backlight unit driver 130A is substantially the same as the backlight unit driver 130 described with reference to FIG. 3 except for the bridge diode 136, the first input terminal 137a, and the second input terminal 137b. In order to avoid duplication, detailed descriptions of the remaining components of the backlight unit driver 130A (a plurality of current controllers, control signal generators, and voltage compensators and their connection relationships) and their operation principles will be omitted.
  • the bridge diode 136 In the backlight unit driver 130A, the bridge diode 136 generates and generates rectified power by rectifying AC power input through a wire 105c connected to an input terminal of a power rectifying unit (see 102 in FIG. 9) of the display device. One rectified power is supplied to the backlight unit 120.
  • the bridge diode 136 corresponds to another power rectifier different from the power rectifier 102 of the display device.
  • the backlight module 140A may be driven by using an input AC power source separately from the power supply of the display device.
  • the first input terminal 137a corresponds to the input terminal of the basic voltage TOV
  • the second input terminal 137b corresponds to the input terminal of the dimming signal V DIMM
  • the basic voltage (TOV) is to increase the driving voltage of the backlight unit by a predetermined voltage TOV so that a plurality of LED groups of the backlight unit are driven at high voltage.
  • the dimming signal V DIMM is to adjust the brightness of the backlight unit to correspond to the brightness of the image displayed on the screen display unit.
  • the backlight unit driver 130A operates so that the overall luminance of the backlight unit follows the level of the dimming signal according to the level (average level, etc.) of the dimming signal for a predetermined period.
  • the backlight unit driver 130A may set the average level of the dimming signal in each multi-stage driving section as the following target level in the multi-stage driving.
  • FIG. 11 is a waveform diagram illustrating an operating principle of the display device of FIG. 9.
  • the display apparatus includes multiple stages of a plurality of LED groups of the backlight unit by the driving voltage V LED and the driving current I LED increased by a predetermined magnitude by the basic voltage TOV. Drive it.
  • the first to fourth voltages Vf5, Vf6, Vf7, and Vf8, which are the reference for the multi-stage driving for the plurality of LED groups, are described with reference to FIG. 4. Since Vf2, Vf3, and Vf4 are higher than the basic voltage TOV, they have substantially the same operating principle as those of the display device of FIG. 4, and thus detailed descriptions thereof will be omitted to avoid duplication.
  • the forward voltages of the first to fourth LED groups 122, 124, 126, and 128 of the plurality of LED groups may also be input AC voltages or rectified voltages according to the first to fourth voltages Vf5, Vf6, Vf7, and Vf8. Higher voltage is achieved, and for this purpose, each LED group may use an LED device having a higher forward voltage than the LED group of FIG. 4 or may have a larger number of LED devices.
  • FIG. 12 is a flowchart illustrating a method of driving a backlight module according to the present invention.
  • the method of driving the backlight module will be described with reference to a process of driving the backlight module by a backlight unit driver that provides illumination to the display apparatus by driving the backlight unit.
  • the backlight unit includes a plurality of LED (Light Emitting Diode) groups each having at least one light emitting diode.
  • the rectified voltage is first generated by rectifying the input AC power through the power rectifying unit (S121).
  • the rectified voltage has a form of pulsation in which the magnitude of the voltage varies periodically with time.
  • a power factor correction voltage is generated by compensating the power factor of the AC power through the power factor compensator arranged at the output terminal of the power rectifier (S122).
  • the power factor correction voltage has a DC component of a predetermined magnitude or more.
  • the predetermined size corresponds to a DC voltage that all the light emitting diodes of the backlight unit can drive.
  • the rectified voltage is received to generate the main driving voltage or the main driving current, and the generated main driving voltage or the main driving current is supplied to the backlight unit (S123).
  • the backlight unit driver is configured to increase the number of LED groups emitting light among the plurality of LED groups as the magnitude of the rectified voltage increases based on the rectified voltage whose voltage varies periodically over time.
  • the unit may be controlled, and the backlight unit may be controlled to reduce the number of LED groups emitting light among the plurality of LED groups as the magnitude of the rectified voltage decreases.
  • the backlight unit driver supplies the supplementary driving voltage or the supplementary driving current by the power factor correction voltage to the backlight unit (S124, S125 and S127).
  • the backlight unit driver includes a rectified voltage V REC that is higher than the minimum voltage V R1 for driving at least one LED group of the plurality of LED groups.
  • V REC rectified voltage
  • the supplementary driving voltage or the supplementary driving current by the power factor correction voltage V PFC may be supplied to the backlight unit BLU.
  • the method of driving the backlight module may further include receiving a dimming signal for controlling the backlight unit driver to generate a set dimming voltage or a set dimming current from the display module. If a dimming signal is received and the set dimming voltage (V DI ) is greater than the LED drive voltage (V LED ) or the set dimming current is greater than the LED drive current, the supplementary drive voltage by the power factor correction voltage (V PFC ) or The supplementary driving current is supplied to the backlight unit (S124, S126, and S127).
  • the dimming signal may correspond to a control signal for maintaining the brightness of the backlight unit at a preset level.
  • the backlight unit driver may generate a set dimming voltage or a set dimming current corresponding to a preset luminance according to the level of the dimming signal.
  • the set dimming voltage or the set dimming current corresponds to the LED driving voltage or the LED driving current corresponding to the level of the dimming signal.
  • the LED driving voltage corresponds to a voltage obtained by adding the aforementioned main driving voltage and the supplementary driving voltage
  • the LED driving current corresponds to a current obtained by adding the aforementioned main driving current and the supplementary driving current.
  • the backlight unit driver may control the backlight unit such that the overall brightness of the backlight unit follows the level of the dimming signal (eg, an average level in a predetermined period) according to the level of the dimming signal.
  • the dimming signal eg, an average level in a predetermined period

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Abstract

La présente invention se rapporte à un module de rétroéclairage, à un procédé permettant de commander ce module d'éclairage et à un dispositif d'affichage qui utilise ce module d'éclairage, une pluralité de diodes électroluminescentes d'une unité de rétroéclairage pouvant être de manière efficace commandées à l'aide d'une tension redressée impulsée et d'une tension corrigée par un facteur de puissance qui comprend un composant à courant continu ayant une taille prédéterminée ou une taille plus importante. Un dispositif d'affichage comprend : une unité rectifiant la puissance destinée à rectifier le courant alternatif et à délivrer une tension rectifiée ; une unité de correction du facteur de puissance destinée recevoir de l'unité rectifiant la puissance la tension rectifiée, à corriger le facteur de puissance du courant alternatif et à délivrer une tension corrigée par le facteur de puissance et qui contient une composante de tension en courant continu qui présente au moins une taille prédéterminée ; un module d'affichage commandé par la tension corrigée par le facteur de puissance ; une unité de rétroéclairage qui comprend une pluralité de diodes électroluminescentes pour fournir un rétroéclairage au module d'affichage ; et une unité de commande d'une unité de rétroéclairage destinée à recevoir la tension rectifiée afin de générer une tension d'attaque principale ou un courant d'attaque principal, à fournir la tension d'attaque principale ou le courant d'attaque principal à une unité de rétroéclairage, à recevoir la tension corrigée par le facteur de puissance lorsque la taille de la tension rectifiée est plus petite qu'une valeur de seuil prédéterminée afin de générer une tension d'attaque supplémentaire ou un courant d'attaque supplémentaire et à fournir la tension d'attaque supplémentaire générée ou le courant d'attaque supplémentaire généré à l'unité de rétroéclairage.
PCT/KR2012/011289 2011-12-21 2012-12-21 Module de rétroéclairage, procédé de commande de ce dernier et dispositif d'affichage qui utilise ce dernier WO2013095055A1 (fr)

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CN109870470A (zh) * 2017-06-30 2019-06-11 京东方科技集团股份有限公司 探测像素电路、探测面板和光电检测装置

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