WO2012051817A1 - 背光电路控制方法、背光电路及升压电路 - Google Patents

背光电路控制方法、背光电路及升压电路 Download PDF

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Publication number
WO2012051817A1
WO2012051817A1 PCT/CN2011/070940 CN2011070940W WO2012051817A1 WO 2012051817 A1 WO2012051817 A1 WO 2012051817A1 CN 2011070940 W CN2011070940 W CN 2011070940W WO 2012051817 A1 WO2012051817 A1 WO 2012051817A1
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WIPO (PCT)
Prior art keywords
voltage
backlight
current
led
circuit
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PCT/CN2011/070940
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English (en)
French (fr)
Inventor
孙钦利
佘海波
张文刚
刘凤鹏
梁茂
Original Assignee
中兴通讯股份有限公司
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Application filed by 中兴通讯股份有限公司 filed Critical 中兴通讯股份有限公司
Priority to EP11833723.7A priority Critical patent/EP2631899B1/en
Priority to US13/880,016 priority patent/US9232594B2/en
Publication of WO2012051817A1 publication Critical patent/WO2012051817A1/zh

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • 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]
    • H05B45/10—Controlling the intensity of the light
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133603—Direct backlight with LEDs
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133612—Electrical details
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133618—Illuminating devices for ambient light
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133626—Illuminating devices providing two modes of illumination, e.g. day-night
    • 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
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0247—Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
    • 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
    • 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
    • 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
    • G09G3/36—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 using liquid crystals

Definitions

  • the present invention relates to the field of communications, and in particular to a backlight circuit control method, a backlight circuit, and a boost circuit.
  • BACKGROUND OF THE INVENTION At present, liquid crystal display (LCD) is used in the terminal, and the backlight brightness of the LCD has a great influence on the imaging effect.
  • Light Emitting Diode (LED) is used as a backlight illumination device.
  • the LED anode is connected to the positive electrode of the battery, and the cathode is connected in series with the brightness balance resistor and then connected to the current control terminal.
  • the number of LEDs required by the terminal is directly related to the display area of the LCD and the luminous power of the LED.
  • this circuit has a disadvantage: The battery voltage gradually decreases with the working time. When the battery voltage drops to a certain level, the backlight brightness cannot be guaranteed; in addition, when the power of the whole machine fluctuates, the brightness of the backlight fluctuates accordingly. For example, when the entertainment terminal plays video and uses the built-in speaker to put it out, if the battery voltage is insufficient, the backlight brightness will flash with the music. The lower the battery voltage, the higher the brightness level, the louder the speaker volume, and the fluctuation of the backlight brightness. The more obvious.
  • some terminal products in the related art use a backlight circuit with a boosting circuit. The advantages of this circuit are: When the battery voltage is low, the LED backlight can still obtain higher work from the boosting circuit.
  • the backlight circuit with the booster circuit solves the problem of brightness fluctuation caused by the power fluctuation of the whole machine at a low voltage, it often brings extra power consumption.
  • the terminal product is powered by a lithium battery, the voltage of the lithium battery is about 4.2V when fully charged, and the voltage of the terminal is automatically turned off by about 3.3V.
  • the boost circuit of the terminal backlight circuit provides a fixed voltage of 4.3V to the LED.
  • Some terminals have adjustable brightness. Under low-light conditions, there is no need to provide 4.3V for the backlight. The excess voltage is consumed at the control terminal, which causes heat loss and reduces the terminal's endurance.
  • a primary object of the present invention is to provide a backlight circuit control method, a backlight circuit, and a booster circuit to solve at least the above problems.
  • a backlight circuit control method including: acquiring a current backlight brightness level of a terminal; determining a minimum voltage required to cause the light emitting diode LED to emit light to reach the brightness level of the backlight; adjusting a boosting circuit to the center The LED provides the minimum voltage.
  • determining a minimum voltage required to achieve the backlight brightness level according to the LED illumination comprises: determining the minimum voltage according to a current value corresponding to the backlight brightness level.
  • the minimum voltage is the sum of the voltages of the LEDs and the resistors connected thereto in series with the voltage of the current control terminal; wherein the current control terminal is used to adjust the current of the LEDs to reach the backlight brightness level.
  • the current controlled voltage is a minimum voltage at which the current control terminal is used to stably output a current required to reach the backlight brightness level.
  • the minimum voltage is the sum of the voltages of the LEDs and the resistors connected thereto in series, plus the voltage of the current control terminal, plus a safety voltage; wherein the current control terminal is used to adjust the current of the LEDs to arrive a value required for the backlight brightness level, the current controlled voltage being a minimum voltage of the current control terminal for stably outputting a current required to reach the backlight brightness level, the safety voltage being used to increase the The minimum voltage determines the stability of the backlight brightness when power fluctuations occur.
  • the method further includes: turning off the boosting circuit when the voltage of the terminal power source is greater than or equal to the minimum voltage, and supplying voltage to the LED by the terminal power source.
  • a backlight circuit including: an obtaining module configured to acquire a current backlight brightness level of the terminal; and a voltage determining module configured to determine that the LED light is illuminated to reach the backlight brightness level The minimum voltage required; an adjustment module configured to adjust the boost circuit to provide the minimum voltage to the LED.
  • the voltage determining module is configured to determine the minimum voltage according to a current value corresponding to the backlight brightness level.
  • the minimum voltage determined by the voltage determining module is a sum of voltages of the LED and a resistor connected in series thereof, and a voltage of the current control terminal; wherein the current control terminal is used to adjust current of the LED To a value required to achieve the backlight brightness level, the current controlled voltage is the minimum voltage at which the current control terminal is used to stably output the current required to reach the backlight brightness level.
  • the minimum voltage determined by the voltage determining module is a sum of a voltage of the LED and a resistor connected in series with a voltage of a current control terminal, and a safety voltage; wherein the power The flow control end is configured to adjust a current of the LED to a value required to reach the brightness level of the backlight, and the current controlled voltage is a current required by the current control end to stably output the brightness level of the backlight.
  • the minimum voltage that is used to increase the minimum voltage to determine the stability of the backlight brightness when power fluctuations occur.
  • a booster circuit for use in a backlight circuit, wherein the booster circuit is configured to provide and adjust a current backlight brightness level to an LED of the backlight circuit by adjusting a voltage.
  • the minimum voltage required Through the invention, the current backlight brightness level of the terminal is obtained; the minimum voltage required to cause the LED to emit light to reach the brightness level of the backlight is determined; and the boost circuit is provided to provide the minimum voltage to the LED.
  • the boost circuit solves the problem in the related art that the boost circuit provides a fixed voltage, thereby causing heat loss and reducing the endurance of the terminal, thereby improving the endurance of the terminal.
  • FIG. 1 is a flowchart of a backlight circuit control method according to an embodiment of the present invention
  • FIG. 2 is a structural block diagram of a backlight circuit according to an embodiment of the present invention
  • FIG. 3 is a booster circuit according to an embodiment of the present invention. Schematic diagram of an LED backlight circuit
  • FIG. 4 is a flow chart of a preferred backlight circuit control method in accordance with an embodiment of the present invention.
  • the screen brightness of the terminal provides one or more backlight brightness levels (or referred to as backlight levels, brightness levels) for user setting
  • the backlight circuit with the boost circuit in the related art only provides a fixed The voltage value, such a process can make the screen flicker regardless of the fluctuation of the battery voltage and the power fluctuation of the whole machine regardless of whether the maximum brightness or the minimum brightness is working, but the LED backlight circuit with the boosting circuit is always at the output end.
  • the LED backlight circuit with the boosting circuit reduces the backlight power consumption and improves the endurance of the terminal product without affecting the normal use of the terminal product.
  • the output voltage of the booster circuit is no longer a fixed value. Under the condition of high backlight brightness level, the boost circuit is set to a high voltage output value; under the low brightness level condition, the boost circuit is set to a low voltage output value. This minimizes the voltage margin at the current control terminal and produces less thermal power. Thereby achieving the purpose of energy saving.
  • Step S102 Acquire a current backlight brightness level of the terminal
  • Step S104 determine to enable the LED The minimum voltage required to reach the current backlight brightness level is illuminated
  • Step S106 adjusting the boost circuit to provide the minimum voltage to the LED.
  • the purpose of changing the brightness of the backlight is achieved by adjusting the current in the LED
  • different backlight brightness levels correspond to different current levels.
  • the minimum voltage can be determined based on the current value corresponding to the backlight brightness level. If the brightness level of the backlight is adjusted by adjusting the current, the operation of the regulated current can be performed by the current control terminal.
  • the minimum voltage can be the sum of the voltage of the LED and the resistor connected in series with the voltage of the current control terminal;
  • the current control terminal is used to adjust the current of the LED to a value required to reach the backlight brightness level, and the current control voltage may be the minimum voltage used by the current control terminal to stably output the current required to reach the backlight brightness level.
  • the minimum voltage can be the sum of the voltage of the LED and the resistor connected in series with the voltage of the current control terminal, plus the safety voltage (for example, 0.2V) is used to increase the minimum voltage to determine The brightness of the backlight is stable when the power fluctuates.
  • FIG. 2 is a structural block diagram of a backlight circuit according to an embodiment of the present invention.
  • the backlight circuit is used to implement the foregoing embodiments and preferred embodiments thereof, which have been described, and will not be further described herein.
  • the backlight circuit includes: an acquisition module 22, a voltage determination module 24, and an adjustment module 26. The structure will be described below.
  • the obtaining module 22 is configured to obtain the current backlight brightness level of the terminal; the voltage determining module 24 is connected to the obtaining module 22, and is configured to determine a minimum voltage required to cause the LED to emit light to reach the current backlight brightness level; the adjusting module 26 is connected to the voltage determining Module 24 is configured to adjust the boost circuit to provide the minimum voltage to the LED.
  • the voltage determining module 24 is configured to determine a minimum voltage according to a current value corresponding to the backlight brightness level.
  • the minimum voltage determined by the voltage determining module 24 is the sum of the voltages of the LEDs and the resistors connected thereto in series with the voltage of the current control terminal; wherein the current control terminal is used to adjust the current of the LEDs to a value required to reach the backlight brightness level.
  • the current controlled voltage is the minimum voltage used by the current control terminal to stabilize the current required to reach the backlight brightness level.
  • the minimum voltage determined by the voltage determining module 24 is the sum of the voltage of the LED and the resistor connected in series with the voltage of the current control terminal, plus the safety voltage; wherein the current control terminal is used to adjust the current of the LED to reach the backlight
  • the current controlled voltage is the minimum voltage used by the current control terminal to stabilize the current required to reach the backlight brightness level
  • the safe voltage is used to increase the minimum voltage to determine the stability of the backlight brightness when power fluctuations occur.
  • a booster circuit is also provided for use in a backlight circuit for providing a minimum voltage required for reaching a current backlight brightness level by adjusting a voltage to an LED of a backlight circuit. .
  • FIG. 3 is a schematic diagram of an LED backlight circuit having a boosting circuit, as shown in FIG. 3, the backlight circuit includes: an LED 1, a brightness balancing resistor 2, a current control terminal 3, and a processor 4 (for The functions of the acquisition module 22, the voltage determination module 24 and the adjustment module 26 described above and the (programmable) boost circuit 5 are implemented.
  • the adjustment of the backlight brightness is achieved by controlling the current level of the current control terminal. If the voltage provided by the LED circuit with the boost circuit is too high, the voltage of the current control terminal is too high, which may form unnecessary. Heat loss. The experiment is performed on a mobile phone.
  • Tables 1 and 2 are the terminals (for example, mobile phones) at the same brightness (the backlight current is the same).
  • the backlight voltage V LED is 4.3V and 5V respectively when the input voltage (ie, the analog battery input voltage) changes. Power situation.
  • Table 1
  • the sum of the voltages of the LEDs and the series resistors (the voltage between the two points in AB in Figure 3) is U L1 , U L2 , ... , U LN ;
  • the corresponding voltage of the current control terminal is U C1 , U C2 , ... , U CN .
  • the magnitude of the backlight current is I ⁇ I ⁇ —IN;
  • the sum of the voltages of the LED and the series resistor is U L1 ⁇ U L2 ⁇ ... ⁇ U LN ;
  • the voltage relationship of the current control terminal is U C1 ⁇ U C2 ⁇ ... ⁇ U CN .
  • the battery voltage U BAT is a variable. When fully charged, U BAT is a higher value.
  • U BAT gradually becomes a lower value.
  • the voltage required to be supplied to the backlight should be at least U L1 + U C1 , U L2 + U C2 , ... , ULN + UCN.
  • the voltage provided by each brightness level can be increased by a little more.
  • the increased voltage is U SAFE to ensure that the brightness of the backlight does not fluctuate when the power fluctuates.
  • the voltage required by the booster circuit for each brightness level is U L1 + U C1 + U SAFE , U L2 + UC2+USAFE , . . . , ULN+UCN+USAFE.
  • a backlight circuit boost output that does not use an energy-saving scheme provides a sufficiently high voltage U OUT ; and U OUT >U BAT , Uoux> ULN+UCN+USAFE, the efficiency at each brightness level is
  • ULI+UCI+USAFE U L2 +U C2 +U SAFE
  • U LN +U CN +U SAFE The efficiencies at each brightness level are U L1 /(U L1 +U C1 +U SAFE ) , U L2 /(U L2 +UC2+USAFE) , . . . ,
  • the boost circuit in order to prevent the boost circuit from operating in the buck state, when the voltage output value of the boost output terminal is lower than the battery voltage value, the boost circuit can be turned off, and the backlight circuit can be bypassed from the battery terminal. Take current. That is, when the brightness level is ⁇ , and
  • the boost circuit When UBAT ⁇ ULN+UCN+USAFE, the boost circuit is turned off and the battery is powered by the bypass diode (to simplify the problem, the forward voltage drop of the diode can be ignored. Of course, the forward voltage drop of the diode can be considered);
  • UBAT ⁇ ULN +UCN+U S AFE the output voltage of the output of the boost circuit is set to
  • the backlight level of the mobile phone is 5, and the backlight of the 1 - 5 brightness corresponds to 3 ⁇ 4f ( Us ): 10mA, 20mA, 30mA, 40mA, 50mA; 1-5 brightness (backlight current 10 -50mA)
  • the sum of the voltages of the corresponding LEDs and series resistors (U L1 -U L5 ) are 2.73V, 2.84V, 2.95V, 3.04V, 3.12V, respectively.
  • the LEDs of different manufacturers are different in the same level of current, and the LED backlight voltage is different, and the maximum value needs to be taken, and Different manufacturers LED backlight circuit VA curve can be real-risk calibration.
  • the maximum voltage (U C1 -U C5 ) corresponding to the current control terminal that can output a stable current at the level 1-5 brightness (backlight current 10-50mA) is 0.24V, 0.25V, 0.26V, 0.27V, 0.27V.
  • the minimum voltage that needs to be supplied to the LED backlight at 1-5 brightness is ( 2.73 + 0.24 ) V, ( 2.84 + 0.25 ) V, ( 2.95 + 0.26 ) V, ( 3.04 + 0.27 ) V, ( 3.12+0.27 ) V, That is 2.97V, 3.09V, 3.21V, 3.31V, 3.39V. Due to the error in the control, in order to ensure sufficient voltage at each brightness, the above maximum voltage is increased by 0.2V (U SAFE ), namely 3.17V, 3.29V, 3.41V, 3.51V, 3.59V.
  • the step voltage of the boost circuit of the mobile phone is 0.1V
  • the above voltage needs to be rounded is 3.2V, 3.3V, 3.5V, 3.6V, 3.6V.
  • the battery voltage can be sampled in software and compared with the boost output voltage required for the set brightness level. If it is higher than the boost output voltage, it is turned off.
  • the output of the boost circuit the backlight voltage is provided by the battery through the bypass diode. 4 is a flowchart of a preferred backlight circuit control method according to an embodiment of the present invention. As shown in FIG.
  • Step S401 Start a backlight in an extinguished state
  • Step S402 determine that a backlight needs to be turned on
  • Step S403 The program reads the backlight level of the brightness setting
  • step S404 reads the corresponding control current from the list (for example, Table 3);
  • Step S405 sets the control current;
  • Step S406 reads the current battery voltage from the list;
  • Step S407 reading the output voltage of the booster circuit from the list;
  • step S408 comparing the battery voltage with the required boosted output voltage;
  • step S409 turning off the output of the booster circuit if the battery voltage is high;
  • the circuit output voltage is the corresponding voltage in the list.
  • Table 4-6 shows the reduction of the overall machine consumption under the brightness of 1, 3, and 5 levels after the above-mentioned mobile phone application energy-saving scheme. Table 4, energy saving under different input voltages at level 1 brightness
  • the energy-saving scheme applied in the preferred embodiment has an obvious energy-saving effect.
  • the backlight power consumption is minimized without affecting the user experience, thereby effectively improving the endurance of the terminal.
  • the above modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device, such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Computer Hardware Design (AREA)
  • Theoretical Computer Science (AREA)
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背光电路控制方法、 背光电路及升压电路 技术领域 本发明涉及通信领域， 具体而言， 涉及一种背光电路控制方法、 背光电 路及升压电路。 背景技术 目前， 在终端中均使用了液晶显示展 ( Liquid Crystal Display, 简称为 LCD ), LCD的背光亮度对成像效果有非常大的影响。 发光二极管 （Light Emitting Diode, 简称为 LED )被应用为背光发光器件， 通常， LED阳极接 电池的正极， 阴极串联亮度平衡电阻后接电流控制端。 终端需要的 LED的个数与 LCD的显示面积及 LED的发光功率直接相 关。 但是， 该电路存在一个缺点： 电池电压随着工作时间逐渐降低， 当电池 电压降到一定程度后， 背光亮度就不能保证； 另外， 当整机功率波动时， 背 光亮度就随之波动。 例如， 娱乐终端播放视频并使用内置扬声器外放时， 若 电池电压不足， 背光亮度就会随着音乐闪烁， 电池电压越低， 亮度等级越高， 扬声器音量越大， 这种背光亮度的波动就越明显。 为了解决上述问题， 在相关技术中部分终端产品釆用了具有升压电路的 背光电路， 这种电路的优点是： 当电池电压较低时， LED背光仍能从升压电 路获得较高的工作电压。这样背光亮度就不会随着整机功率的波动而闪烁了。 虽然， 具有升压电路的背光电路解决了低电压下整机功率波动时导致的 亮度波动的问题， 但是， 却往往会带来额外的功率消耗。 例如， 终端产品釆 用 1节锂电池供电，锂电池充满电时的电压 4.2V左右， 终端自动关机的电压 3.3V左右。 该终端背光电路的升压电路向 LED提供固定的 4.3V的电压。 有 些终端的亮度可调节，在低亮度条件下并不需要为背光提供 4.3V的电压， 多 余的电压会消耗在控制端， 形成热损耗， 降低了终端的续航能力。 发明内容 本发明的主要目的在于提供一种背光电路控制方法、 背光电路及升压电 路， 以至少解决上述问题。 根据本发明的一个方面， 提供了一种背光电路控制方法， 包括： 获取终 端当前的背光亮度等级；确定使发光二极管 LED发光达到所述背光亮度等级 所需要的最小电压； 调整升压电路向所述 LED提供所述最小电压。 优选地,确定根据所述 LED发光达到所述背光亮度等级所需要的最小电 压包括： 根据所述背光亮度等级所对应的电流值确定所述最小电压。 优选地，所述最小电压为所述 LED及与其串联的电阻的电压之和加上电 流控制端的电压； 其中， 所述电流控制端用于将所述 LED的电流调整到达到 所述背光亮度等级所需要的值， 所述电流控制的电压为所述电流控制端用于 稳定输出达到所述背光亮度等级所需要的电流的最小电压。 优选地，所述最小电压为所述 LED及与其串联的电阻的电压之和加上电 流控制端的电压， 再加上安全电压； 其中， 所述电流控制端用于将所述 LED 的电流调整到达到所述背光亮度等级所需要的值， 所述电流控制的电压为所 述电流控制端用于稳定输出达到所述背光亮度等级所需要的电流的最小电 压，所述安全电压用于提高所述最小电压以确定功率波动时背光亮度的稳定。 优选地， 上述方法还包括： 在终端电源的电压大于或等于所述最小电压 的情况下， 关闭所述升压电路， 由所述终端电源向所述 LED提供电压。 根据本发明的另一个方面， 还提供了一种背光电路， 包括： 获取模块， 设置为获取终端当前的背光亮度等级； 电压确定模块， 设置为确定使发光二 极管 LED发光达到所述背光亮度等级所需要的最小电压； 调整模块，设置为 调整升压电路向所述 LED提供所述最小电压。 优选地， 所述电压确定模块， 设置为根据所述背光亮度等级所对应的电 流值确定所述最小电压。 优选地，所述电压确定模块确定的所述最小电压为所述 LED及与其串联 的电阻的电压之和加上电流控制端的电压； 其中， 所述电流控制端用于将所 述 LED的电流调整到达到所述背光亮度等级所需要的值，所述电流控制的电 压为所述电流控制端用于稳定输出达到所述背光亮度等级所需要的电流的最 小电压。 优选地，所述电压确定模块确定的所述最小电压为所述 LED及与其串联 的电阻的电压之和加上电流控制端的电压， 再加上安全电压； 其中， 所述电 流控制端用于将所述 LED的电流调整到达到所述背光亮度等级所需要的值， 所述电流控制的电压为所述电流控制端用于稳定输出达到所述背光亮度等级 所需要的电流的最小电压， 所述安全电压用于提高所述最小电压以确定功率 波动时背光亮度的稳定。 根据本发明的再一个方面， 还提供了一种升压电路， 用于背光电路中， 所述升压电路，用于通过电压的调整向所述背光电路的 LED提供与达到当前 的背光亮度等级所需要的最小电压。 通过本发明， 釆用获取终端当前的背光亮度等级； 确定使发光二极管 LED发光达到该背光亮度等级所需要的最小电压； 调整升压电路向 LED提 供该最小电压。 解决了相关技术中由于升压电路提供固定不变的电压从而导 致形成热损耗、 降低终端续航能力的问题， 进而提高了终端的续航能力。 附图说明 此处所说明的附图用来提供对本发明的进一步理解， 构成本申请的一部 分， 本发明的示意性实施例及其说明用于解释本发明， 并不构成对本发明的 不当限定。 在附图中： 图 1是根据本发明实施例的背光电路控制方法的流程图； 图 2是根据本发明实施例的背光电路的结构框图； 图 3是根据本发明实施例的具有升压电路的 LED背光电路的示意图； 图 4是根据本发明实施例优选的背光电路控制方法的流程图。 具体实施方式 下文中将参考附图并结合实施例来详细说明本发明。 需要说明的是， 在 不冲突的情况下， 本申请中的实施例及实施例中的特征可以相互组合。 在以下实施例中， 终端的屏幕亮度提供了一个或多个背光亮度等级 （或 称为背光等级、 亮度等级） 供用户设置， 在相关技术中具有升压电路的背光 电路只提供了一个固定的电压值， 这样的处理虽然可以使屏幕不论工作在最 大亮度还是最小亮度都不会因为电池电压的降低而整机功率的波动而闪烁， 但是， 具有升压电路的 LED背光电路总是在输出端提供足够的电压， 这样在 低亮度等级下所提供的电压会富余很多， 这些电压会分配到其他电路上 （例 如， 电流控制电路） 形成不必要的热损耗， 减低终端的续航能力。 以下实施 例 4十对具有升压电路的 LED背光电路， 在不影响终端产品正常使用的情况 下， 降低背光功耗， 提高终端产品的续航能力。 在以下实施例中， 升压电路的输出电压就不再是一个固定值。 高背光亮 度等级条件下， 设置升压电路为一个高的电压输出值； 低亮度等级条件下， 设置升压电路为一个低的电压输出值。 这样就可以使电流控制端的电压富余 最小， 产生的热功耗也就越小。 从而达到节能的目的。 图 1是根据本发明实施例的背光电路控制方法的流程图， 如图 1所示， 该流程包括如下步 4聚： 步骤 S 102, 获取终端当前的背光亮度等级； 步骤 S 104 ,确定使 LED发光达到当前背光亮度等级所需要的最小电压； 步骤 S 106 , 调整升压电路向 LED提供该最小电压。 通过上述步骤， 使升压电路提供的电压可以调整， 这样在一个较低亮度 时就可以提供一个比较低的电压， 从而相对于相关技术中只提供固定电压的 升压电路降低了热损耗。 优选地， 在实施时， 如果是通过调节 LED中的电流达到改变背光亮度的 目的， 那么， 不同的背光亮度等级对应不同的电流等级。 LED工作电流越大， LED两端的电压也就越高； 相反， LED工作电流越小， LED两端的电压也 就越低。 在这种情况下， 可以根据背光亮度等级所对应的电流值确定最小电 压。 如果通过调节电流来调节背光亮度等级， 那么， 该调节电流的工作可以 由电流控制端来完成， 此时， 最小电压可以为 LED及与其串联的电阻的电压 之和加上电流控制端的电压； 其中， 电流控制端用于将 LED的电流调整到达 到背光亮度等级所需要的值， 电流控制的电压可以为电流控制端用于稳定输 出达到背光亮度等级所需要的电流的最小电压。 为了使背光亮度更加稳定， 最小电压可以为 LED及与其串联的电阻的电压之和加上电流控制端的电压， 再加上安全电压， 该安全电压 （例如， 0.2V ) 用于提高最小电压以确定功率 波动时背光亮度的稳定。 优选地， 为了防止升压电路工作在降压状态， 在终端的电源电压大于或 等于最小电压的情况下， 关闭升压电路， 由电源向 LED提供电压。 图 2是根据本发明实施例的背光电路的结构框图， 该背光电路用于实现 上述实施例及其优选实施例方式， 已经进行过说明的， 在此不再赘述， 下面 仅对该电路中涉及到的模块进行说明。 如图 2所示， 该背光电路包括： 获取 模块 22、 电压确定模块 24、 调整模块 26 , 下面对此结构进行说明。 获取模块 22 , 设置为获取终端当前的背光亮度等级； 电压确定模块 24 连接至获取模块 22 , 设置为确定使发光二极管 LED发光达到当前背光亮度 等级所需要的最小电压； 调整模块 26连接至电压确定模块 24 , 设置为调整 升压电路向 LED提供该最小电压。 优选地， 电压确定模块 24 , 设置为根据背光亮度等级所对应的电流值确 定最小电压。 优选地， 电压确定模块 24确定的最小电压为 LED及与其串联的电阻的 电压之和加上电流控制端的电压； 其中， 电流控制端用于将 LED的电流调整 到达到背光亮度等级所需要的值， 电流控制的电压为电流控制端用于稳定输 出达到背光亮度等级所需要的电流的最小电压。 优选地， 电压确定模块 24确定的最小电压为 LED及与其串联的电阻的 电压之和加上电流控制端的电压， 再加上安全电压； 其中， 电流控制端用于 将 LED的电流调整到达到背光亮度等级所需要的值，电流控制的电压为电流 控制端用于稳定输出达到背光亮度等级所需要的电流的最小电压， 安全电压 用于提高最小电压以确定功率波动时背光亮度的稳定。 在本实施例中， 还提供了一种升压电路， 用于背光电路中， 该升压电路， 用于通过电压的调整向背光电路的 LED提供与达到当前的背光亮度等级所 需要的最小电压。 图 3是根据本发明实施例的具有升压电路的 LED背光电路的示意图，如 图 3所示， 该背光电路包括： LED 1、 亮度平衡电阻 2、 电流控制端 3、 处理 器 4 (用于实现上述的获取模块 22、 电压确定模块 24和调整模块 26的功能） 和 （可程控） 升压电路 5。 下面结合图 3对一个优选实施例进行说明。 在本优选实施例中， 背光亮度的调节是通过控制电流控制端的电流大小 实现的， 具有升压电路的 LED电路若提供的电压过高，会使电流控制端的电 压过高， 会形成不必要的热损耗。 实验在某手机上进行， 表 1和表 2是终端 (例如， 手机） 在相同亮度下 （背光电流相同） 背光电压 VLED分别为 4.3V 和 5V在输入电压 （即模拟电池输入电压） 变化时的功率情况。 表 1
表 2
Figure imgf000008_0001
从表中可以看出在输入电压艮接近时， 如表 1的 3.98V和表 2的 3.96V, 不同的背光电压对应的整机功率也是不同的， 较低的背光电压对应的整机功 耗也较小。 以上数据说明， 在不影响背光亮度的情况下尽量低的电压会降低 整机功耗。 终端产品往往在界面上提供若千亮度等级供用户选择，假设有 N级亮度， 各亮度等级对应的背光电流 （各路 LED电流之和） 为 11 Ι2 , . . . , IN; 对应 的 LED及串联电阻的电压之和（图 3中 AB两点间的电压）为， UL1 , UL2, ... , ULN; 对应的电流控制端的最 4氐电压为 UC1 , UC2, ... , UCN。 背光电流的大小关系为 I^I^— IN; LED及串联电阻的电压之和的大小 关系为 UL1<UL2<... <ULN; 电流控制端的电压大小关系为 UC1<UC2<... <UCN。 电池电压 UBAT是一个变量， 充满电时 UBAT是一个较高的值， 随着终端续航 时间的延长， UBAT逐渐变为一个较低的值。 各亮度等级下， 需要给背光提供的电压至少应为 UL1+UC1 , UL2+UC2, ... , ULN+UCN, 保险起见， 各亮度等级提供的电压可以再提高一点， 设该提高的 电压为 USAFE, 以保证功率波动时背光亮度不随之波动。 这样， 升压电路需 要给各亮度等级提供的电压为 UL1+UC1+USAFE , UL2+UC2+USAFE , . . . , ULN+UCN+USAFE。 不釆用节能方案的背光电路升压输出端提供一个足够高的电压 UOUT;并 且 UOUT>UBAT , Uoux> ULN+UCN+USAFE 其各亮度等级下的效率分别为
(ULi /iUouT , (UL2*I2)/(UOUT*I2), (ULN*IN)/(UOUT*IN), 化简后为 ULI/UOUT , UL2/UOUT , ULN/UOUT, 可以看出， 当亮度等级设置越低， 其 效率就越氐。 釆用本实施例的节能方案的背光电路升压输出端并非一直提供一个很高 的电压， 而是为各亮度等级提供一个可正常工作的最低电压， 其电压值
ULI+UCI+USAFE , UL2+UC2+USAFE , ULN+UCN+USAFE。 其各亮度等级下的 效率分别为 UL1/(UL1+UC1+USAFE) , UL2/(UL2+UC2+USAFE) , . . . ,
ULN/(ULN+UCN+USAFE) » 由于 （ UL1+UC1+USAFE )
<(UL2+UC2+USAFE)<. - - <ULN+UCN+USAFE<UOUT ,所以釆用节能方案后效率较之 前有提高。 需要注意的是， 为了防止升压电路工作在降压状态， 所以当升压输出端 输出的电压计算值低于电池电压值时， 可以关闭升压电路， 背光电路可以通 过旁路二极管从电池端取电流。 即， 当亮度等级为 Ν, 并且
UBAT≥ULN+UCN+USAFE时， 关闭升压电路， 由电池通过旁路二极管供电（为简 化问题， 可以忽略二极管的正向压降， 当然， 可以考虑二极管的正向压降）； UBAT<ULN+UCN+USAFE时， 升压电路的输出端输出电压设置为
ULN+UCN+USAFE。 现以手机为例说明， 该手机背光等级为 5级， 1 -5级亮度对应的背光电 ¾f ( Us ) 分别为： 10mA, 20mA, 30mA, 40mA, 50mA; 1-5级亮度 （背 光电流 10-50mA ) 对应的 LED及串联电阻的电压之和 （ UL1-UL5 ) 分别为 2.73V, 2.84V, 2.95V, 3.04V, 3.12V。 需要说明的是， 口果釆用不同厂家的 LED, 同等级电流不同厂家 LED背光电压不同， 需要取其中的最大值， 并且 不同厂家 LED背光电路 VA曲线可以实-险标定。 1-5级亮度 （背光电流 10-50mA )下电流控制端对应的可以输出稳定电流的最氐电压（UC1-UC5 )分 别为 0.24V, 0.25V, 0.26V, 0.27V, 0.27V。
1-5级亮度下需要提供给 LED背光的最低电压为 （ 2.73+0.24 ) V, ( 2.84+0.25 ) V, ( 2.95+0.26 ) V, ( 3.04+0.27 ) V, ( 3.12+0.27 ) V, 即 2.97V, 3.09V, 3.21V, 3.31V, 3.39V。 由于控制中存在误差， 为了保证各亮度下的 电压足够， 以上最氐电压再提高 0.2V ( USAFE ), 即 3.17V, 3.29V, 3.41V, 3.51V, 3.59V。 由于该手机升压电路电压调节的步进值为 0.1V, 所以上述电 压需要圓整 （不能四舍五入， 否则可能会电压不足） 为 3.2V, 3.3V, 3.5V, 3.6V, 3.6V。 表 3
Figure imgf000010_0001
需要注意， 为了防止升压电路工作在降压状态， 可以在软件上对电池电 压进行釆样， 并与所设置亮度等级需要的升压输出电压进行比较， 若高于升 压输出电压， 则关闭升压电路的输出， 背光电压由电池通过旁路二极管提供。 图 4是根据本发明实施例优选的背光电路控制方法的流程图， 如图 4所 示， 该流程包括如下步骤： 步骤 S401 , 开始背光处于熄灭状态； 步骤 S402 , 确定需要点亮背光； 步骤 S403 , 程序读取亮度设置的背光等级； 步骤 S404, 从列表（例如， 表 3 ) 中读取相应的控制电流； 步骤 S405 , 设置控制电流； 步骤 S406, 从列表中读取当前电池电压； 步骤 S407, 从列表中读取升压电路的输出电压; 步骤 S408, 对电池电压和需要的升压输出电压进行比较； 步骤 S409, 若电池电压高则关闭升压电路的输出； 否则设置升压电路输 出电压为列表中对应的电压。 实验效果： 表 4-6是上述手机应用节能方案后在 1、 3、 5级亮度下相对 于普通方案的整机降耗情况。 表 4, 1级亮度下不同输入电压下节能情况
Figure imgf000011_0001
表 5 , 3级亮度下不同输入电压下节能情况
Figure imgf000011_0002
表 6, 5级亮度下不同输入电压下节能情况
节能方案电流 普通方案电流 降耗率 输入电压 （V ) ( mA ) ( mA ) ( % )
4.20 81.80 90.00 34.44 9.11
4.10 81.20 91.70 43.05 11.45
4.00 81.50 93.60 48.40 12.93
3.90 81.80 95.10 51.87 13.99
3.80 81.90 97.60 59.66 16.09 3.70 82.10 98.80 61.79 16.90
3.60 81.30 99.20 64.44 18.04
3.50 74.00 93.00 66.50 20.43
3.40 68.90 87.90 64.60 21.62 从以上实验数据可以看出， 本优选实施例中的应用节能方案有明显的节 能效果。 综上所述， 对于具有升压电路的 LED电路， 应用上述实施例之后， 在不 影响用户体验的前提下最大程度降低背光功耗，有效提高了终端的续航能力。 显然， 本领域的技术人员应该明白， 上述的本发明的各模块或各步骤可 以用通用的计算装置来实现， 它们可以集中在单个的计算装置上， 或者分布 在多个计算装置所组成的网络上， 可选地， 它们可以用计算装置可执行的程 序代码来实现， 从而， 可以将它们存储在存储装置中由计算装置来执行， 并 且在某些情况下， 可以以不同于此处的顺序执行所示出或描述的步骤， 或者 将它们分别制作成各个集成电路模块， 或者将它们中的多个模块或步骤制作 成单个集成电路模块来实现。 这样， 本发明不限制于任何特定的硬件和软件 结合。 以上所述仅为本发明的优选实施例而已， 并不用于限制本发明， 对于本 领域的技术人员来说， 本发明可以有各种更改和变化。 凡在本发明的^"神和 原则之内， 所作的任何修改、 等同替换、 改进等， 均应包含在本发明的保护 范围之内。

Claims

权 利 要 求 书
1. 一种背光电路控制方法， 包括：
获取终端当前的背光亮度等级；
确定使发光二极管 LED发光达到所述背光亮度等级所需要的最 小电压；
调整升压电路向所述 LED提供所述最小电压。
2. 居权利要求 1所述的方法， 其中， 确定才艮据所述 LED发光达到所述 背光亮度等级所需要的最小电压包括：
根据所述背光亮度等级所对应的电流值确定所述最小电压。
3. 根据权利要求 2所述的方法， 其中， 所述最小电压为所述 LED及与其 串联的电阻的电压之和加上电流控制端的电压； 其中， 所述电流控制 端用于将所述 LED的电流调整到达到所述背光亮度等级所需要的值， 所述电流控制的电压为所述电流控制端用于稳定输出达到所述背光亮 度等级所需要的电流的最小电压。
4. 根据权利要求 2所述的方法， 其中， 所述最小电压为所述 LED及与其 串联的电阻的电压之和加上电流控制端的电压， 再加上安全电压； 其 中， 所述电流控制端用于将所述 LED的电流调整到达到所述背光亮度 等级所需要的值， 所述电流控制的电压为所述电流控制端用于稳定输 出达到所述背光亮度等级所需要的电流的最小电压， 所述安全电压用 于提高所述最小电压以确定功率波动时背光亮度的稳定。
5. 根据权利要求 1至 4中任一项所述的方法， 其中， 还包括：
在终端电源的电压大于或等于所述最小电压的情况下， 关闭所述 升压电路， 由所述终端电源向所述 LED提供电压。
6. —种背光电路， 包括：
获取模块， 设置为获取终端当前的背光亮度等级； 电压确定模块，设置为确定使发光二极管 LED发光达到所述背光 亮度等级所需要的最小电压； 调整模块， 设置为调整升压电路向所述 LED提供所述最' j、电压。 根据权利要求 6所述的背光电路， 其中， 所述电压确定模块， 设置为 根据所述背光亮度等级所对应的电流值确定所述最小电压。 根据权利要求 7所述的背光电路， 其中， 所述电压确定模块确定的所 述最小电压为所述 LED及与其串联的电阻的电压之和加上电流控制端 的电压； 其中， 所述电流控制端用于将所述 LED的电流调整到达到所 述背光亮度等级所需要的值， 所述电流控制的电压为所述电流控制端 用于稳定输出达到所述背光亮度等级所需要的电流的最小电压。 根据权利要求 7所述的背光电路， 其中， 所述电压确定模块确定的所 述最小电压为所述 LED及与其串联的电阻的电压之和加上电流控制端 的电压， 再加上安全电压； 其中， 所述电流控制端用于将所述 LED的 电流调整到达到所述背光亮度等级所需要的值， 所述电流控制的电压 为所述电流控制端用于稳定输出达到所述背光亮度等级所需要的电流 的最小电压， 所述安全电压用于提高所述最小电压以确定功率波动时 背光亮度的稳定。
一种升压电路， 用于背光电路中，
所述升压电路，用于通过电压的调整向所述背光电路的 LED提供 与达到当前的背光亮度等级所需要的最小电压。
PCT/CN2011/070940 2010-10-20 2011-02-11 背光电路控制方法、背光电路及升压电路 WO2012051817A1 (zh)

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