WO2021082895A1 - 一种背光控制电路及其控制方法、显示终端 - Google Patents

一种背光控制电路及其控制方法、显示终端 Download PDF

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Publication number
WO2021082895A1
WO2021082895A1 PCT/CN2020/120474 CN2020120474W WO2021082895A1 WO 2021082895 A1 WO2021082895 A1 WO 2021082895A1 CN 2020120474 W CN2020120474 W CN 2020120474W WO 2021082895 A1 WO2021082895 A1 WO 2021082895A1
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Prior art keywords
voltage
terminal
current
feedback signal
coupled
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PCT/CN2020/120474
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English (en)
French (fr)
Inventor
张世雄
禹秀泳
陈敏
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华为技术有限公司
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Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP20883265.9A priority Critical patent/EP3937161B1/en
Priority to US17/618,079 priority patent/US20220322511A1/en
Publication of WO2021082895A1 publication Critical patent/WO2021082895A1/zh

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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
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G09G3/342—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
    • G09G3/3426—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines the different display panel areas being distributed in two dimensions, e.g. matrix
    • 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
    • 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
    • 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
    • H05B45/14—Controlling the intensity of the light using electrical feedback from LEDs or from LED modules
    • 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
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/02—Details of power systems and of start or stop of display operation
    • G09G2330/021—Power management, e.g. power saving
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/02—Details of power systems and of start or stop of display operation
    • G09G2330/025—Reduction of instantaneous peaks of current
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/02—Details of power systems and of start or stop of display operation
    • G09G2330/028—Generation of voltages supplied to electrode drivers in a matrix display other than LCD

Definitions

  • This application relates to the field of display technology, and in particular to a backlight control circuit, a control method thereof, and a display terminal.
  • LCD liquid crystal display
  • the LCD includes a liquid crystal display panel and a backlight module for providing light sources to the liquid crystal display panel.
  • the direct-lit backlight module can control the brightness of the area and has a better display effect.
  • the direct type backlight module includes a plurality of light strings and a driving chip coupled with the light strings.
  • the forward voltage (VF) of the light string that is, the voltage corresponding to the rated current
  • VF forward voltage
  • the voltage value of the port coupled to each light string in the driver chip changes, and there is a phenomenon that the port voltage value is inconsistent. If the port voltage is relatively large, the power consumption of the driver chip will be relatively large.
  • the embodiments of the present application provide a backlight control circuit, a control method thereof, and a display terminal, which are used to reduce the voltage difference of each port in the driving chip, so that it works in a reasonable working interval, reduces power consumption and improves efficiency.
  • a backlight control circuit drives at least one light string group.
  • the light string group includes a plurality of light strings connected in parallel.
  • the backlight control circuit includes a drive circuit and a power conversion circuit.
  • the driving circuit has a feedback signal terminal and at least one channel port; the channel port is coupled to the first terminal of the light string group; the driving circuit is used to obtain the voltage Vch of each channel port, and based on the voltage Vch, the feedback signal terminal provides current Feedback signal.
  • the power conversion circuit is coupled to the feedback signal terminal and has a voltage output terminal. The voltage output terminal is used to provide a supply voltage to the second terminal of each light string group.
  • the power conversion circuit is used to convert the input voltage and increase or decrease the above-mentioned power supply voltage according to the current feedback signal.
  • the voltage Vch of each channel port of the driving circuit can be kept within a certain range, avoiding that the voltage at the first end of the light string group is less than the turning voltage or the inflection point voltage of the channel port, resulting in abnormal brightness of the light string group, or avoiding the light
  • the voltage at the first end of the string is too large, causing the power consumption of the driving circuit to increase.
  • a feedback signal terminal capable of providing a current feedback signal is provided on the driving circuit, and the feedback signal terminal is coupled to the power conversion circuit.
  • the drive circuit to provide a current feedback signal to the power conversion circuit in real time according to the voltage Vch of each channel port.
  • the power conversion circuit can adjust the power supply voltage output from its voltage output terminal in real time according to the current feedback signal, that is, increase the power supply voltage or decrease the power supply voltage.
  • the power supply voltage received by the second end of the light string group can be adjusted within a certain range, which can prevent the voltage Vch of each channel port of the driving circuit from remaining high for a long time. Or a lower state, and can reduce the difference between the voltage Vch1 of each channel port of the driving circuit, and finally achieve the purpose of reducing the power consumption of the driving circuit.
  • the feedback signal provided by the feedback signal port coupled to the drive circuit and the power conversion circuit is a current feedback signal. Compared with the voltage signal, the current signal will not be affected by the distance between the driving circuit and the power conversion circuit and cause greater fluctuations, so that signal interference caused by wiring noise can be reduced.
  • the driving circuit is specifically configured to compare the voltage Vch of each channel port with the first preset voltage VL and the second preset voltage VH. Among them, VL ⁇ VH.
  • the driving circuit is also specifically used to provide a first current I1 as a current feedback signal from the feedback signal terminal when the voltage Vch of any channel port is less than the first preset voltage VL, and the first current I1 is used to increase the foregoing Supply voltage.
  • the feedback signal terminal provides a second current I2 as a current feedback signal, and the second current I2 is used to reduce the supply voltage.
  • the first current I1 and the second current I2 have opposite directions.
  • the feedback signal end of the drive circuit can provide the first current I1 (ie sink current) to boost the supply voltage output by the voltage output end of the power conversion circuit, and the feedback signal end of the drive circuit can provide the second current.
  • I1 ie sink current
  • I2 ie, source current
  • the backlight control circuit provided by the embodiment of the present application can perform bidirectional adjustment of the voltage at the second end of the light string group.
  • the driving circuit includes a comparator, a first current source, and a second current source.
  • the input terminal of the comparator is connected to the channel port, the first output terminal of the comparator is coupled to the control terminal of the first current source, and the second output terminal of the comparator is connected to the control terminal of the second current source. Coupling.
  • the comparator is used to compare the voltage Vch of each channel port with the first preset voltage VL and the second preset voltage VH, and when the voltage Vch of any channel port is less than the first preset voltage VL, the first output terminal
  • the first control signal is output; when the voltage Vch of all the channel ports is greater than the second preset voltage VH, the second output terminal outputs the second control signal.
  • VL ⁇ VH.
  • the first pole of the first current source is coupled to the feedback signal terminal, and the second pole is coupled to the first voltage terminal.
  • the first current source is used to receive the above-mentioned first control signal, and the feedback signal terminal provides the first current I1.
  • the first pole of the second current source is coupled to the second voltage terminal, and the second pole is coupled to the feedback signal terminal.
  • the second current source is used for receiving the second control signal, and the feedback signal terminal provides a second current I2.
  • the first voltage terminal is used to output the first voltage V1
  • the second voltage terminal is used to output the second voltage V2,
  • the feedback signal end of the driving circuit can provide the first current I1 (ie sink current) and the technical effect of providing the second current I2 (ie source current) as described above, and will not be repeated here.
  • the power conversion circuit includes a first resistor having a resistance value R1.
  • the first end of the first resistor is coupled to the voltage output end, and the second end of the first resistor is coupled to the feedback signal end.
  • the backlight control circuit further includes a second resistor.
  • the first end of the second resistor is coupled to the second end of the first resistor, and the second end of the second resistor is coupled to the feedback signal end of the driving circuit.
  • the second resistor is used to perform impedance matching between the second end of the first resistor and the feedback signal end.
  • the driving circuit is further specifically configured to continuously increase the current S times by the first current I1 provided by the feedback signal terminal when the voltage Vch of any channel port is less than the first preset voltage VL for S consecutive times.
  • S ⁇ 2 is a positive integer.
  • the power conversion circuit is also specifically configured to increase the voltage of the voltage output terminal by the voltage change amount ⁇ V according to the first current I1 each time.
  • the driving circuit can continue to detect the voltage Vch of all channel ports every frame, when the driving circuit continuously detects that the voltage Vch of any channel port is less than the first preset voltage VL (for example, The feedback signal terminal outputs the first current I1 once every two frames, and the duration of S times is S ⁇ 2 frames, that is, the driving circuit detects that the voltage Vch of any channel port is less than the first preset piezoelectric VL) for S ⁇ 2 consecutive frames.
  • the first current I1 provided by the feedback signal terminal will continuously increase the current change ⁇ I for S times in a stepwise manner, so the current value of the first current I1 provided by the feedback signal terminal for the third time is S ⁇ I.
  • the power conversion circuit increases the voltage at the voltage output terminal by the voltage change ⁇ V according to the first current I1 each time, so the voltage output from the voltage output terminal Vout of the third power conversion circuit increases by S ⁇ V on the basis of the original voltage. .
  • the above-mentioned voltage change amount ⁇ V1
  • the driving circuit is also specifically configured to determine that the voltage Vch of any channel port is less than the first preset after the first current I1 provided by the feedback signal terminal is continuously increased by the current change amount ⁇ I in a stepwise manner.
  • the voltage VL the feedback signal terminal is in a high impedance state. Since there are open light strings in the multiple light string groups, no matter how the voltage value of the power supply voltage output by the voltage output terminal of the power conversion circuit is adjusted upwards, the second end of the open light string is connected to the channel port. The voltage is still less than the first preset piezoelectric VL.
  • the drive circuit can output an open circuit signal to the control system of the display terminal to achieve the purpose of open circuit detection.
  • the driving circuit is further specifically configured to continuously decrease the second current I2 provided by the feedback signal terminal in a stepwise manner when the voltage Vch of all the channel ports is greater than the second preset voltage VH for N consecutive times.
  • the amount of current change ⁇ I is also specifically configured to reduce the voltage at the voltage output terminal by the voltage change amount ⁇ V according to the second current I1 each time.
  • the driving circuit can continue to detect the voltage Vch of all the channel ports every frame, when the driving circuit detects that the voltage Vch of all the channel ports is greater than the second preset voltage VH for N consecutive times, the feedback
  • the second current I2 provided by the signal terminal will continuously reduce the current change ⁇ I in a stepwise manner N times, so the current value of the second current I2 provided by the Nth feedback signal terminal is N ⁇ I.
  • the power conversion circuit reduces the voltage at the voltage output terminal by the voltage change amount ⁇ V according to the second current I2 each time, so the voltage output by the voltage output terminal Vout of the Nth power conversion circuit is reduced by N ⁇ on the basis of the original voltage. V.
  • the amount of voltage change ⁇ V1
  • the technical effect of the first resistor R1 is the same as described above, and will not be repeated here.
  • the driving circuit further has a plurality of gate ports and a power supply port coupled to each gate port, and the power supply port is also coupled to the voltage output terminal of the power conversion circuit.
  • a plurality of light string groups are arranged in an array; the second end of the multiple light string groups in the same row is coupled to a gate port; the first end of the light string group in the same column is coupled to a channel port of the driving circuit . In this way, one channel port can be respectively connected to the first end of the light string group in the same column, so the number of channel ports in the driving circuit can be reduced.
  • the voltage output terminal of the power conversion circuit is coupled to the first terminal of each light string group.
  • the voltage output terminal of the power conversion circuit can simultaneously provide the above-mentioned power supply voltage to the second terminal of the light string group.
  • a control method of a backlight control circuit is provided.
  • the backlight control circuit is used to drive at least one light string group.
  • the light string group includes a plurality of light strings connected in parallel.
  • the backlight control circuit includes a drive circuit and a power conversion circuit.
  • the driving circuit has a feedback signal terminal and at least one channel port.
  • the channel port is coupled to the first end of the light string group.
  • the power conversion circuit is coupled to the feedback signal terminal and has a voltage output terminal.
  • the above-mentioned control method includes: first, the driving circuit obtains the voltage Vch of the channel port, and based on the above-mentioned voltage Vch, the feedback signal terminal provides a current feedback signal. Next, the power conversion circuit increases or decreases the supply voltage of the voltage output terminal according to the current feedback signal.
  • the control method of the backlight control circuit has the same technical effect as the backlight control circuit provided in the foregoing embodiment, and will not be repeated here.
  • the driving circuit acquiring the voltage Vch of the channel port and providing the current feedback signal specifically includes: first, the driving circuit compares the voltage Vch of each channel port with the first preset voltage VL and the second preset voltage VH; Among them, VL ⁇ VH. Next, when the voltage Vch of any channel port is less than the first preset voltage VL, the feedback signal terminal of the driving circuit provides a first current I1 as a current feedback signal, and the first current I1 is used to increase the supply voltage. Alternatively, when the voltage Vch of all the channel ports is greater than the second preset voltage, the feedback signal terminal of the driving circuit provides the second current I2 as the current feedback signal, and the second current I2 is used to reduce the supply voltage.
  • first current I1 and the second current I2 have opposite directions.
  • the feedback signal end of the driving circuit can provide the first current I1 (ie sink current) and the technical effect of providing the second current I2 (ie source current) as described above, and will not be repeated here.
  • the driving circuit includes a comparator, a first current source, and a second current source.
  • the input terminal of the comparator is connected to the channel port.
  • the first output terminal of the comparator is coupled to the control terminal of the first current source.
  • the first pole of the first current source is coupled to the feedback signal terminal, and the second pole is coupled to the first voltage terminal.
  • the second output terminal of the comparator is coupled to the control terminal of the second current source.
  • the first pole of the second current source is coupled to the second voltage terminal, and the second pole is coupled to the feedback signal terminal.
  • the first voltage terminal is used to output the first voltage V1
  • the second voltage terminal is used to output the second voltage V2,
  • the driving circuit acquiring the voltage Vch of the channel port and providing the current feedback signal specifically includes: first, the comparator compares the voltage Vch of each channel port with the first preset voltage VL and the second preset voltage VH. Among them, VL ⁇ VH. Next, when the voltage Vch of any channel port is less than the first preset voltage V, the first output terminal of the comparator outputs the first control signal, the first current source receives the first control signal, and the feedback signal terminal provides the first control signal. Current I1. Or, when the voltage Vch of all the channel ports is greater than the second preset voltage, the second output terminal of the comparator outputs the second control signal, the second current source receives the second control signal, and the feedback signal terminal provides the second current I2 .
  • the feedback signal end of the driving circuit can provide the first current I1 (ie sink current) and the technical effect of providing the second current I2 (ie source current) as described above, and will not be repeated here.
  • the power conversion circuit includes a first resistor having a resistance value R1.
  • the first end of the first resistor is coupled to the voltage output end, and the second end of the first resistor is coupled to the feedback signal end.
  • the driving circuit obtains the voltage Vch of the channel port, and provides the current feedback signal from the feedback signal terminal based on the voltage Vch.
  • the current feedback signal includes the first signal provided by the feedback signal terminal when the voltage Vch of any channel port is less than the first preset voltage VL for S consecutive times.
  • the current I1 continuously increases the current change ⁇ I in a stepwise manner for S times. Among them, S ⁇ 2, and S is a positive integer.
  • the power conversion circuit increases or decreases the supply voltage of the voltage output terminal according to the current feedback signal.
  • the technical effects of the driving circuit, the power conversion circuit and the first resistor are the same as those described above, and will not be repeated here.
  • the method further includes: first, after the first current I1 provided by the feedback signal terminal of the drive circuit is continuously increased by the current variation ⁇ I in a stepwise manner, it is determined that the voltage Vch of any channel port is less than the first current I1.
  • the feedback signal end of the driving circuit is in the high-impedance power conversion circuit.
  • the voltage at the voltage output terminal of the power conversion circuit is restored to the initial voltage.
  • the power conversion circuit includes a first resistor having a resistance value R1.
  • the first end of the first resistor is coupled to the voltage output end, and the second end of the first resistor is coupled to the feedback signal end.
  • the driving circuit obtains the voltage Vch of the channel port, and provides the current feedback signal from the feedback signal terminal based on the voltage Vch.
  • the feedback signal includes: when the voltage Vch of all the channel ports is greater than the second preset voltage VH for N consecutive times, the second signal provided by the feedback signal terminal
  • the second current I2 continuously reduces the current change ⁇ I in a stepwise manner N times. Among them, N ⁇ 2; N is a positive integer.
  • the power conversion circuit increasing or decreasing the power supply voltage of the voltage output terminal according to the current feedback signal includes: the power conversion circuit reduces the voltage of the voltage output terminal by the voltage change amount ⁇ V according to the second current I1 each time.
  • the amount of voltage change ⁇ V1
  • a display terminal which includes a liquid crystal display panel and a backlight module for providing a light source to the liquid crystal display panel.
  • the backlight module includes a plurality of lamp string groups and a backlight control circuit.
  • the light string group includes multiple light strings connected in parallel; each light string includes multiple light emitting devices connected in series.
  • the backlight control circuit includes a drive circuit and a power conversion circuit.
  • the driving circuit has a feedback signal terminal and at least one channel port. The channel port is coupled to the first end of the light string group; the driving circuit is used to obtain the voltage Vch of each channel port, and based on the voltage Vch, the feedback signal terminal provides a current feedback signal.
  • the power conversion circuit is coupled to the feedback signal terminal and has a voltage output terminal.
  • the voltage output terminal is used to provide a supply voltage to the second terminal of each light string group.
  • the power conversion circuit is used to increase or decrease the supply voltage of the voltage output terminal according to the current feedback signal.
  • the display terminal has the same technical effect as the backlight control circuit provided in the foregoing embodiment, and will not be repeated here.
  • the liquid crystal display panel includes a plurality of sub-pixels arranged in an array. Multiple light string groups are arranged in an array. The vertical projection of the area where the M ⁇ N sub-pixels are located on the backlight module overlaps the area where a light string group is located; where M ⁇ 1, N ⁇ 1, and N and M are positive integers. In this way, one channel port of the driving circuit can control the brightness of at least one light string group, so there is no need to individually control the brightness of each light string.
  • the area where the light string group is located can correspond to the area where the M ⁇ N sub-pixels in the liquid crystal display panel are located, so as to achieve the purpose of regional dimming of the picture displayed by the display terminal.
  • the driving circuit further has a plurality of gate ports and a power supply port coupled to each gate port, and the power supply port is also coupled to the voltage output terminal of the power conversion circuit.
  • the backlight module also includes a plurality of second signal lines and first signal lines.
  • a second signal line is respectively coupled to the second ends of the multiple light string groups in the same row and a gate port.
  • a first signal line is respectively coupled to the first end of the lamp string group in the same column and a channel port of the driving circuit.
  • the power supply port of the drive circuit can provide the power supply voltage to each gate port one by one.
  • the above-mentioned multiple first signal lines can transmit the voltage of the first end of each light string group in the same row to each channel port row by row.
  • the driving circuit can be used to obtain the voltage of each channel port, and generate a current feedback signal according to the magnitude of the voltage of each channel port.
  • one channel port can be connected to the first end of the light string group in the same column, so the number of channel ports in the driving circuit can be reduced.
  • a driving circuit has a feedback signal terminal and at least one channel port. Wherein, the channel port is coupled to the first end of the light string group.
  • the driving circuit is used to obtain the voltage Vch of each channel port, and based on the voltage Vch, the feedback signal terminal provides a current feedback signal to the power conversion circuit, so that the power conversion circuit increases or decreases the output voltage according to the current feedback signal.
  • the technical effect of the driving circuit is the same as that described above, and will not be repeated here.
  • the driving circuit is specifically configured to compare the voltage Vch of each channel port with the first preset voltage VL and the second preset voltage VH. Among them, VL ⁇ VH.
  • the driving circuit is also specifically used to provide a first current I1 as a current feedback signal from the feedback signal terminal when the voltage Vch of any channel port is less than the first preset voltage VL, and the first current I1 is used to increase the foregoing Supply voltage.
  • the feedback signal terminal provides a second current I2 as a current feedback signal, and the second current I2 is used to reduce the supply voltage.
  • the first current I1 and the second current I2 have opposite directions. The technical effects of the first current I1 and the second current I2 are the same as described above, and will not be repeated here.
  • the driving circuit includes a comparator, a first current source, and a second current source.
  • the input terminal of the comparator is connected to the channel port, the first output terminal of the comparator is coupled to the control terminal of the first current source, and the second output terminal of the comparator is connected to the control terminal of the second current source. Coupling.
  • the comparator is used to compare the voltage Vch of each channel port with the first preset voltage VL and the second preset voltage VH, and when the voltage Vch of any channel port is less than the first preset voltage VL, the first output terminal
  • the first control signal is output; when the voltage Vch of all the channel ports is greater than the second preset voltage VH, the second output terminal outputs the second control signal.
  • VL ⁇ VH.
  • the first pole of the first current source is coupled to the feedback signal terminal, and the second pole is coupled to the first voltage terminal.
  • the first current source is used to receive the above-mentioned first control signal, and the feedback signal terminal provides the first current I1.
  • the first pole of the second current source is coupled to the second voltage terminal, and the second pole is coupled to the feedback signal terminal.
  • the second current source is used for receiving the second control signal, and the feedback signal terminal provides a second current I2.
  • the first voltage terminal is used to output the first voltage V1
  • the second voltage terminal is used to output the second voltage V2,
  • the feedback signal end of the driving circuit can provide the first current I1 (ie sink current) and the technical effect of providing the second current I2 (ie source current) as described above, and will not be repeated here.
  • FIG. 1 is a schematic structural diagram of a display terminal provided by an embodiment of the application.
  • FIG. 2a is a schematic diagram of the structure of a plurality of light string groups provided by an embodiment of the application
  • FIG. 2b is a schematic diagram of the corresponding relationship between the light string group and the sub-pixels shown in FIG. 2a;
  • 3a is a schematic diagram of a connection relationship between a backlight control circuit and a plurality of light string groups provided by an embodiment of the application;
  • FIG. 3b is a schematic diagram of another connection relationship between a backlight control circuit and a plurality of light string groups provided by an embodiment of the application;
  • FIG. 3c is a schematic diagram of another connection relationship between a backlight control circuit and a plurality of light string groups provided by an embodiment of the application;
  • 4a is a schematic diagram of the relationship between the temperature and the forward voltage of the light string provided by an embodiment of the application;
  • Fig. 4b is a schematic diagram of the voltage values of each channel port in Fig. 3a;
  • FIG. 5 is a flowchart of a control method of a backlight control circuit provided by an embodiment of the application
  • FIG. 6 is a flowchart of specific steps of S101 in FIG. 5;
  • FIG. 7 is a schematic diagram of a connection of a driving circuit, a power conversion circuit, and a plurality of light string groups provided by an embodiment of the application;
  • FIG. 8 is a schematic diagram of another connection of a driving circuit, a power conversion circuit, and a plurality of light string groups provided by an embodiment of the application;
  • FIG. 9 is a schematic diagram of output voltages at different stages of the voltage output terminal of the power conversion circuit provided by an embodiment of the application.
  • azimuth terms such as “upper”, “lower”, “left”, “right”, etc. may include but are not limited to the directions defined relative to the schematic placement of the components in the drawings. It should be understood that these directions sexual terms can be relative concepts, and they are used for relative description and clarification, and they can change correspondingly according to the changes in the orientation of the parts in the drawings.
  • Coupled may be a way of electrical connection for signal transmission. Unless otherwise clearly specified and limited, “coupling” may be a direct electrical connection, or an indirect electrical connection through an intermediate medium.
  • the embodiment of the present application provides a display terminal.
  • the display terminal includes, for example, a TV, a mobile phone, a tablet computer, a personal digital assistant (PDA), a vehicle-mounted computer, and the like.
  • PDA personal digital assistant
  • the embodiments of the present application do not impose special restrictions on the specific form of the above-mentioned display terminal.
  • Any one of the above-mentioned display terminals includes an LCD.
  • the display terminal 01 includes a liquid crystal display panel 10 and a backlight unit (BLU) 20.
  • BLU backlight unit
  • the liquid crystal display panel 10 includes a cell aligner substrate 100 and an array substrate 101 which are arranged oppositely.
  • the cell substrate 100 and the array substrate 101 are cell-coupled to form a liquid crystal cell.
  • the liquid crystal display panel 10 also has a liquid crystal layer 102 filled between the cell substrate 100 and the array substrate 101.
  • the above-mentioned backlight module 20 includes a reflective sheet 201, a plurality of light-emitting devices 202 arranged on the reflective sheet 201, and a multilayer optical film 203 on the light-emitting side of the light-emitting device 202.
  • the above-mentioned optical module 203 may be a diffusion sheet, a prism sheet, or the like.
  • the above-mentioned light emitting device 202 may be a light emitting diode (LED). Based on this, a plurality of light emitting devices 202 can be connected in series to form a light string 200 as shown in FIG. 2a. A plurality of light strings 200 can be connected in parallel to form a light string group 21. A light string group 21 can be used as a backlight control area capable of individually controlling brightness, so as to realize local dimming of the backlight module 20 to achieve the purpose of enhancing the contrast of the picture.
  • LED light emitting diode
  • a plurality of sub-pixels 120 in the liquid crystal display panel 10 are arranged in an array.
  • the multiple light string groups 21 in the backlight module 20 are also arranged in an array. Based on this, the vertical projection of the area where the M ⁇ N sub-pixels 120 are located on the backlight module 20 overlaps the area where a light string group 21 is located. That is, when the light-emitting brightness of a light string group 21 is controlled, the display brightness of the area where the M ⁇ N sub-pixels 120 are located can be controlled.
  • M ⁇ 1, N ⁇ 1, and N and M are positive integers.
  • M ⁇ 1, N ⁇ 1, and N and M are positive integers.
  • a row of light string groups 21 arranged along the X direction is called the same row of light string groups 21, along Y
  • a row of light string groups 21 arranged in a direction is referred to as the same row of light string groups 21.
  • the display terminal 01 provided in the embodiment of the present application further includes a backlight control circuit 30 as shown in FIG. 3a.
  • the backlight control circuit 30 includes a driving circuit 301 and a power conversion circuit 302.
  • the aforementioned backlight control circuit 30 can be arranged on the middle frame 02 (as shown in FIG. 1) on the side of the backlight module 20 away from the liquid crystal display panel 10.
  • the side of the middle frame 02 facing away from the liquid crystal display panel 10 is also provided with a main board of the display terminal 01.
  • the aforementioned backlight control circuit 30 may be integrated on the main board.
  • the backlight control circuit 30 and the main board may be independently arranged on the middle frame 02.
  • the backlight control circuit 30 may be integrated in the backlight module 20.
  • the driving circuit 301 may be an integrated circuit (IC).
  • the power conversion circuit 302 may be a direct current (DC) to direct current, that is, a DC/DC direct current power chip.
  • the input terminal Vin (as shown in FIG. 3a) of the DC/DC power supply chip is used to receive an input voltage, and perform voltage conversion on the input voltage as an output voltage.
  • the battery voltage of the display terminal 01 or the output of other power supply circuits can be used as the input of the DC/DC DC power supply chip.
  • the input of the DC/DC power supply chip needs to consider the load power consumption of the light string group 21 as a load, and the input of the DC/DC DC power supply chip also needs to meet the transient performance requirements of the light string group 21.
  • the power conversion circuit 302 can be used as a booster circuit to boost the input voltage. Therefore, the voltage output terminal Vout of the power conversion circuit 302 can output the power supply voltage VLED that can make each light string 200 in the light string group 21 emit light normally.
  • the power conversion circuit 302 can be used as a step-down circuit to perform step-down processing on the input voltage to output the above-mentioned supply voltage VLED from its voltage output terminal Vout.
  • a light-emitting device 202 on a light string 200 needs a voltage of about 3V when it emits light normally.
  • the power supply voltage VLED 30V required by the second end a of the light string 200.
  • the aforementioned power conversion circuit 302 can convert the input voltage received by the input terminal Vin into a power supply voltage of 30V.
  • the above-mentioned driving circuit 301 has a feedback output (FBO) and at least one channel port (for example, CH1, CH2, ... in FIG. 3a).
  • FBO feedback output
  • one channel port is coupled to the first end c of at least one light string group 21 (that is, the cathode of each light string 200 in the light string group 21).
  • the driving circuit 301 may be provided with a light-emitting control current source 323 as shown in FIG. 3b that is respectively coupled to each of the above-mentioned channel ports (for example, CH1, CH2, ... in FIG. 3a).
  • the light emission control current source 323 can provide a constant source current to the channel port CH coupled to the light emission control current source 323.
  • the above-mentioned sourced current is transmitted through the channel port CH to each of the light strings 200 connected in parallel in the light string group 21 coupled to the channel port, so that each light string 200 in the light string group 21 can be driven to emit light.
  • the rated current flowing through the light string group 21 matches the turning voltage or knee voltage of the channel port CH.
  • the voltage of the channel port CH of the driving circuit 301 is less than the above-mentioned turning voltage
  • the light-emitting control current source 323 coupled to the channel port CH cannot provide the above-mentioned rated current to the light string group 21, and the light string group 21 cannot normally emit light. Therefore, in order for the light string group 21 to have normal luminous brightness, the voltage of the channel port CH needs to be greater than the turning voltage of the channel port CH.
  • a pulse width modulation (PWM) signal with an adjustable duty cycle can be used to adjust the duty cycle of the PWM signal according to the requirements of the luminous brightness.
  • PWM pulse width modulation
  • one channel port of the driving circuit 301 can be coupled to at least one light string group 21, so there is no need to couple each light string 200 to one channel port.
  • the area where the light string group 21 is located can correspond to the area where the M ⁇ N sub-pixels 120 in the liquid crystal display panel 10 are located, so as to achieve the purpose of performing regional dimming on the screen displayed by the display terminal 01.
  • each light string 200 can also be coupled to one channel port, so that more channel ports need to be provided on the driving circuit 301.
  • the power conversion circuit 302 in the backlight control circuit 30 may be coupled to the feedback signal terminal FBO of the driving circuit 301.
  • the power conversion circuit 302 has a voltage output terminal Vout.
  • the voltage output terminal Vout is used to provide the supply voltage VLED to the second terminal a of each light string group 21 (that is, the anode of each light string 200 in the light string group 21).
  • the backlight module 20 when the backlight module 20 further includes a plurality of first signal lines SLc as shown in FIG. 3a, the above-mentioned channel ports (CH1, CH2...) and the respective light string groups 21
  • the connection method may be that one first signal line SLc is respectively coupled to the first end c of the light string group 21 in the same column (Y direction) and one channel port CH of the driving circuit 301.
  • the backlight module 20 further includes a plurality of second signal lines SLa as shown in FIG. 3a, and the driving circuit 301 also has a plurality of strobe ports (SW1, SW2%) and each strobe port (SW1, SW2). 7)
  • the coupled power supply port Vps is also coupled to the voltage output terminal Vout of the power conversion circuit 302. Therefore, the voltage output terminal Vout of the power conversion circuit 302 can transmit the above-mentioned power supply voltage VLED to the power supply port Vps of the driving circuit 301.
  • the power conversion circuit 302 can provide the power supply voltage VLED to the second end a of each light string group 21.
  • one second signal line SLa is connected to multiple lines in the same row (X direction).
  • the second end a of the light string group 21 is coupled to a strobe port SW1.
  • the power supply port Vps of the driving circuit 301 can provide the power supply voltage VLED to each gate port (SW1, SW2, ...) one by one.
  • the multiple first signal lines SLc can transmit the voltage of the first terminal c of each light string group 21 in the same row (X direction) to each channel port (CH1, CH2%) row by row.
  • the drive circuit 301 can be used to obtain the voltage (Vch1, Vch2%) of each channel port (CH1, CH2%), and generate a current feedback signal based on the magnitude of the above voltage (Vch1, Vch2%) .
  • the current feedback signal can be provided to the power conversion circuit 302 by the feedback signal terminal FBO of the driving circuit 301.
  • the above-mentioned channel ports (CH1, CH2...) are connected to each light string group 21 in a manner that one first signal line SLc and one light string The first terminal c of the group 21 is coupled.
  • the drive can be reduced.
  • each channel port (CH1, CH2%) of the driving circuit 301 is connected to each light string group 21 as shown in FIG. 3c, the voltage output terminal Vout of the power conversion circuit 302 can be directly connected to the light string group of each row.
  • the second end a of 21 is coupled.
  • the driving circuit 301 can directly obtain the voltages (Vch1, Vch2%) of the various channel ports (CH1, CH2%), and use the feedback
  • the signal terminal FBO provides a current feedback signal.
  • the backlight control circuit 30 is described below by taking the structure shown in FIG. 3a as an example.
  • FIG. 4a is a curve change diagram of the temperature of the light string 200 and the forward voltage VF when the rated operating current IF of the light string 200 is 3 mA.
  • the power conversion circuit 302 is coupled to the feedback signal terminal FBO of the driving circuit 301. Therefore, after the power conversion circuit 302 performs voltage conversion on the input voltage, it can also be used to fine-tune the converted voltage according to the current feedback signal provided by the feedback signal terminal FBO of the drive circuit 301 to obtain the above-mentioned supply voltage VLED, and pass the voltage The output terminal Vout is output. Thus, the purpose of adjusting the voltage of the second terminal a of the light string group 21 is achieved.
  • the voltage at the second end a of the light string group 21 is adjusted, since the source current flowing through the light string group 21 is fixed, the voltage at the second end a of the light string group 21 is the above-mentioned driving
  • the voltage (Vch1, Vch2%) of each channel port (CH1, CH2%) of the circuit 301 will follow the change of the voltage at the second terminal a of the light string group 21, so that the first terminal of the light string group 21
  • the voltage of c is greater than the turning voltage of the channel port CH of the driving circuit 301, so as to ensure that the light string group 21 can emit light with normal brightness.
  • the voltage Vch of each channel port of the driving circuit 301 can be maintained within a certain range, thereby ensuring the normal luminous brightness of the light string group 21 and reducing the power consumption of the driving circuit.
  • the power conversion circuit 302 can reduce the power supply voltage VLED output from the voltage output terminal Vout of the power conversion circuit 302 according to the current feedback signal, due to the light-emitting control current source 323 providing the current source to the light string group 21 Therefore, the voltage of the second terminal a of the light string group 21, that is, the voltage Vch of the channel port CH coupled to the second terminal a of the light string group 21 in the driving circuit 301, is fixed and unchanged.
  • the driving circuit 301 when the forward voltage VF of the light string group 21 increases, causing the voltage Vch of the channel port CH of the driving circuit 301 coupled to the first end c of the light string group 21 to decrease, the driving circuit 301 will By providing another current feedback signal to the power conversion circuit 302.
  • the power conversion circuit 302 can increase the supply voltage VLED output by the voltage output terminal Vout of the power conversion circuit 302 according to the current feedback signal. Since the above-mentioned light-emitting control current source 323 draws a current to the body of the light string group 21, the voltage at the second end a of the light string group 21 is the same as the second terminal a of the light string group 21 in the driving circuit 301. The voltage Vch of the channel port CH coupled to the terminal a increases accordingly.
  • a feedback signal terminal FBO capable of providing a current feedback signal is provided on the driving circuit 301, and the feedback signal terminal FBO is connected to the power conversion circuit 302. Coupling.
  • the drive circuit 301 can provide the current feedback signal to the power conversion circuit 302 according to the voltage (Vch1, Vch2%) of each channel port (CH1, CH2%) of the drive circuit 301 in real time. Based on this, the power conversion circuit 302 can bidirectionally adjust the power supply voltage VLED output by its voltage output terminal Vout in real time according to the current feedback signal.
  • the supply voltage VLED received by the second end of the light string group 21 can be adjusted within a certain range (for example, about 300mV) to prevent the voltage Vch of the channel port CH from being lower than the channel port CH.
  • the turning voltage of the port CH causes the light-emitting brightness of the light string group 21 to be abnormal. Or, avoid that the voltage Vch of the channel port CH is too large, causing the power consumption of the driving circuit to increase.
  • the voltage (Vch1, Vch2%) of each channel port (CH1, CH2%) of the drive circuit 301 can be prevented from maintaining a high or low state for a long time, and each channel port of the drive circuit 301 can be reduced.
  • the difference between the voltages (Vch1, Vch2%) of (CH1, CH2%) ultimately achieves the purpose of reducing the power consumption of the driving circuit 301.
  • the feedback signal provided by the feedback signal port FBO coupled to the driving circuit 301 and the power conversion circuit 302 is a current feedback signal.
  • the current signal will not be affected by the distance between the driving circuit 301 and the power conversion circuit 302 and cause greater fluctuations, so that signal interference caused by wiring noise can be reduced.
  • an embodiment of the present application provides a control method of the backlight control circuit, as shown in FIG. 5, including S101 and S102.
  • the driving circuit 301 obtains the voltages (Vch1, Vch2,%) of each channel port (CH1, CH2%), and provides a current feedback signal from the feedback signal terminal FBO.
  • This S101 specifically includes S201 to S203 as shown in FIG. 6.
  • the driving circuit 301 compares the voltages (Vch1, Vch2%) of the respective channel ports (CH1, CH2%) with the first preset voltage VL and the second preset voltage VH. Among them, VL ⁇ VH.
  • the channel port voltage Vch when the channel port voltage Vch is in the range of VL to VH, the power consumption of the driving circuit 301 is small and can be ignored.
  • the channel port voltage Vch is not within the range of VL to VH, for example, when the channel port voltage Vch is less than the first preset voltage VL, it is easy to make the voltage Vch of the channel port CH smaller than the turning voltage of the channel port CH, resulting in The luminous brightness of the light string group 21 is abnormal.
  • the channel port voltage Vch is greater than the second preset voltage VH, the channel port voltage Vch has a greater impact on the power consumption of the driving circuit 301.
  • the feedback signal terminal FBO of the driving circuit 301 needs to provide a current feedback signal to the power conversion circuit 302, so that the power conversion circuit 302 can real-time obtain the power supply voltage VLED output by its voltage output terminal Vout according to the current feedback signal. Adjust, and finally adjust the voltage of the channel port CH to the range of VL ⁇ VH.
  • the present application does not limit the values of the first preset voltage VL and the second preset voltage VH, and can be set according to the performance of the driving circuit 301 and the power consumption that can be withstood.
  • the driving circuit 301 may include a comparator 311 as shown in FIG. 7.
  • the input terminal of the comparator 311 is coupled to each channel port CH.
  • the comparator 311 also has two reference voltage input terminals for inputting a first preset voltage VL and a second preset voltage VH to the comparator 311, respectively.
  • the comparator 311 when the comparator 311 is coupled to multiple channel ports CH, as an example, the comparator 311 may be connected to each channel port respectively, and the voltage Vch of each channel port is compared with the first preset voltage VL and The second preset voltage VH is compared.
  • the present application does not limit the manner in which the comparator 311 compares the voltages of the multiple channel ports CH to which it is coupled.
  • the comparator 311 can compare the voltages (Vch1, Vch2%) of the respective channel ports (CH1, CH2%) with the first preset voltage VL and the second preset voltage VH.
  • the comparator 311 also has a first output terminal O1 and a second output terminal O2.
  • the comparison result of the comparator 311 is any channel
  • the voltage Vch of the port CH is less than the first preset voltage VL, that is, when any Vch ⁇ VL, the first output terminal O1 of the comparator 311 outputs a valid signal.
  • the comparison result of the comparator 311 is that the voltages Vch of all the channel ports CH are greater than the second preset voltage VH, that is, when all Vch>VH, in order to reduce the power consumption of the driving circuit 301
  • the first of the comparator 311 The second output terminal O2 outputs a valid signal.
  • the driving circuit 301 provides a current feedback signal from the feedback signal terminal FBO of the driving circuit 301 based on the voltages (Vch1, Vch2,...) of the respective channel ports.
  • the comparator 311 in the driving circuit 301 can obtain the voltage Vch of all the channel ports, and then determine whether the voltage Vch of each channel port is Less than the first preset voltage VL. Next, according to the judgment result of the voltage Vch of all the channel ports, it is obtained whether the voltage Vch of any one of the channel ports CH is less than the first preset voltage VL among the voltages Vch of all the channel ports.
  • the comparator 311 in the driving circuit 301 can sequentially determine whether the voltage Vch of each channel port is less than the physical setting position of each channel port CH.
  • the first preset voltage VL When the voltage Vch of one channel port is less than the first preset voltage VL, it is considered that the voltage Vch of any channel port CH is less than the first preset voltage VL.
  • the present application does not limit the manner in which the driving circuit 301 determines that the voltage Vch of any channel port CH is less than the first preset voltage VL.
  • the driving circuit 301 may include a first current source 321 as shown in FIG. 7, and the first current source 321 is used to perform the above-mentioned S202.
  • the control terminal (Con) of the first current source 321 is coupled to the first output terminal O1 of the comparator 311.
  • the first electrode of the first current source 321 (for example, the positive electrode "+”) is coupled to the feedback signal terminal FBO of the driving circuit 301, and the second electrode (for example, the negative electrode "-") is coupled to the first voltage terminal, and the first voltage terminal is used for To output the first voltage V1.
  • the above-mentioned first voltage terminal may be the ground terminal GND, and the first voltage V1 is 0V or a low level.
  • the first current I1 generated by the first current source 321 can flow to the driving circuit 301 sink current (sink).
  • the first output terminal O1 of the comparator 311 outputs a valid signal as the first control signal, and when The control terminal (Con) of the first current source 321 starts to work when receiving the above-mentioned first control signal, and generates the first current I1, which is used as the current feedback signal provided by the feedback signal terminal FBO of the driving circuit 301.
  • the comparator 311 in the driving circuit 301 can detect the voltage Vch of each channel port CH every frame, and the user can set the reporting time of the detection result of the comparator 311 according to needs.
  • the above detection result can be reported once every frame or two frames.
  • the driving circuit 301 After the comparator 311 in the driving circuit 301 reports the detection result each time (for example, one time can be two frames), when the driving circuit 301 obtains the voltage Vch of any channel port according to the detection result reported by the comparator 311, the voltage Vch is continuous.
  • the number of times for example, S times is S ⁇ 2 frames, where S ⁇ 2; S is a positive integer
  • the first current I1 provided by the feedback signal terminal FBO of the driving circuit 301 can be stepped Increase the current change ⁇ I each time.
  • the first current I1 provided by the feedback signal terminal FBO of the drive circuit 301 increases in a stepwise manner by the current change ⁇ I refers to the first current provided by the feedback signal terminal FBO of the drive circuit 301 each time
  • the current value of I1 will increase the current change amount ⁇ I on the basis of the current value of the first current I1 provided last time.
  • the power conversion circuit 302 increases the power supply voltage VLED of the voltage output terminal Vout according to the above-mentioned current feedback signal.
  • the feedback signal terminal FBO of the driving circuit 301 provides the first current I1 as the current feedback signal.
  • the first current I1 is the sink current flowing to the driving circuit 301, the power is converted according to the characteristics of the current flowing from a high potential to a low potential.
  • the output supply voltage VLED will increase on the basis of the original voltage.
  • the feedback of the driving circuit 301 In the case where the first current I1 provided by the signal terminal FBO increases by the current change amount ⁇ I in a stepwise manner, in the loop composed of the plurality of lamp string groups 21, the power conversion circuit 302, and the driving circuit 301, due to the first A current I1 is the sink current flowing to the drive circuit 301.
  • the power conversion circuit 302 increases the voltage of the voltage output terminal Vout, that is, the supply voltage VLED, according to the first current I1 every time.
  • the amount of change ⁇ V is the amount of change ⁇ V.
  • the power conversion circuit 302 increases the supply voltage VLED output from the voltage output terminal Vout according to the first current I1
  • the voltage changes ⁇ V are equal, so that the supply voltage VLED can be increased uniformly.
  • the voltage of the second end a of the light string group 21 (that is, the power supply voltage VLED) can be evenly increased each time.
  • the voltage of the first terminal c of the light string group 21, that is, the voltage of the channel port CH of the driving circuit 301 also rises uniformly each time, and is within the range of VL to VH.
  • the above-mentioned power conversion circuit 302 may include a first resistor R1 as shown in FIG. 8.
  • the resistance value of the first resistor is also represented by R1.
  • the power conversion circuit 302 in order to enable the voltage output terminal Vout of the power conversion circuit 302 to normally output the supply voltage VLED, the power conversion circuit 302 is further provided with a third resistor R3 connected in series with the first resistor R1.
  • the first end of the third resistor R3 away from the first resistor R1 is coupled to the ground GND.
  • the voltage of the voltage output terminal Vout is divided by the first resistor R1 and the third resistor R3 to obtain the voltage of the node FB.
  • the voltage of the node FB can enter the error determiner (not shown in the figure) of the power conversion circuit 302 to compare with the reference voltage inside the power conversion circuit 302, so that the voltage output terminal Vout outputs a normal power supply. Voltage VLED.
  • the first terminal of the first resistor R1 is coupled to the voltage output terminal Vout of the power conversion circuit 302, and the second terminal of the first resistor R1 is coupled to the feedback signal terminal FBO of the driving circuit 301.
  • the above-mentioned voltage change amount ⁇ V
  • the present application does not limit the resistance value of the first resistor R1, and can be set according to the voltage variation ⁇ V and the magnitude of the first current I1 each time the power supply voltage VLED is fine-tuned.
  • the first current I1 generated by the above-mentioned first current source 321 may be several hundred mA.
  • the voltage variation ⁇ V for fine-tuning the supply voltage VLED each time can be set to several hundreds of mV, for example, 300 mV. At this time, the resistance of the first resistor R1 may be less than 300K ⁇ .
  • the aforementioned backlight control circuit 30 may further include a second resistor R2.
  • the first end of the second resistor R2 is coupled to the second end of the first resistor R1, and the second end of the second resistor R2 is coupled to the feedback signal terminal FBO of the driving circuit 301.
  • the second resistor is used to perform impedance matching between the second terminal of the first resistor R1 and the feedback signal terminal FBO of the driving circuit 301.
  • the driving circuit 301 may include a second current source 322 as shown in FIG. 7, and the second current source 322 is used to perform the above-mentioned S203.
  • the control terminal (Con) of the second current source 322 is coupled to the second output terminal O2 of the comparator 311.
  • the first electrode (for example, the positive electrode “+”) of the second current source 322 is coupled to the second voltage terminal VCC.
  • the second voltage terminal VCC is used to output the second voltage V2.
  • the second pole (for example, the negative electrode “-”) of the second current source 322 is coupled to the feedback signal terminal FBO of the driving circuit 301.
  • the second voltage V2 output by the second voltage terminal VCC may be a high level.
  • the voltage value of the first voltage V1 output by the first voltage terminal, such as the ground terminal GND is smaller than the second voltage V2 output by the second voltage terminal VCC, that is,
  • the second output terminal O2 of the comparator 311 outputs a valid signal, which can be called the second control
  • the control terminal (Con) of the second current source 322 receives the above-mentioned second control signal, it starts to work and generates the second current I2, which is used as the current feedback signal provided by the feedback signal terminal FBO of the driving circuit 301.
  • the second current I2 generated by the second current source 322 can be Source of the power conversion circuit 302. Based on this, the directions of the first current I1 and the second current I2 are opposite.
  • the power conversion circuit 302 reduces the supply voltage VLED of the voltage output terminal Vout according to the above-mentioned current feedback signal.
  • the feedback signal terminal FBO of the driving circuit 301 provides the second current I2 as the current feedback signal.
  • the second current I2 is the source current flowing to the power conversion circuit 302, according to the characteristics of the current flowing from a high potential to a low potential, the power supply The voltage output terminal Vout of the conversion circuit 302, and the output power supply voltage VLED will be reduced on the basis of the original voltage.
  • the same principle can be obtained when the voltage Vch of all channel ports CH is continuous N times (for example, once corresponds to 2 frames, N times is N ⁇ 2 frames, where N ⁇ 2; N is a positive integer) are greater than the second preset
  • the second current I2 provided by the feedback signal terminal FBO of the driving circuit 301 will decrease the current variation ⁇ I each time in a stepwise manner.
  • the power conversion circuit 302 since the second current I2 is the source current flowing to the power conversion circuit 302, according to the characteristics of the current flowing from a high potential to a low potential, the power supply The conversion circuit 302 reduces the voltage of the voltage output terminal Vout, that is, the supply voltage VLED, by the voltage change amount ⁇ V according to the second current I2 each time.
  • the power conversion circuit 302 reduces the supply voltage VLED output by the voltage output terminal Vout according to the second current I2.
  • the small voltage changes ⁇ V are equal, so that the power supply voltage VLED can be reduced uniformly.
  • the voltage of the second terminal a of the light string group 21 (that is, the power supply voltage VLED) can be uniformly reduced every time. Therefore, the voltage of the first terminal c of the light string group 21, that is, the voltage of the channel port CH of the driving circuit 301, will uniformly decrease each time, and is within the range of VL to VH.
  • the comparator 311 in the driving circuit 301 can detect the voltage Vch of all the channel ports CH in each frame.
  • the driving circuit 301 can provide the first current I1 (ie, sink current) every time according to the detection result of the comparator 311 to increase the supply voltage VLED output by the voltage output terminal Vout of the power conversion circuit 302.
  • the feedback signal terminal FBO of the driving circuit 301 may provide a second current I2 (ie, a source current) according to the detection result of the comparator 311 each time, so as to reduce the power supply voltage output by the voltage output terminal Vout of the power conversion circuit 302 VLED. Therefore, the backlight control circuit 30 provided by the embodiment of the present application can bidirectionally adjust the voltage of the second terminal a of the light string group 21.
  • the voltage output terminal Vout of the power conversion circuit 302 shown in FIG. 8 can pass through the power supply port of the driving circuit 301 Vps provides the initial voltage Vref to the second end a of each light string group 21.
  • the comparator 311 in the driving circuit 301 may pass a preset time, for example, 1 frame (with a duration of P), and detect that the voltages Vch of all the channel ports CH are greater than the second preset voltage. VH, and output an effective control signal to the control terminal con of the second current source 322.
  • the second current source 322 generates the second current I2 (source current) as the current feedback signal provided by the feedback signal terminal FBO.
  • the power conversion circuit 302 reduces the voltage at the voltage output terminal Vout of the power conversion circuit 302 according to the second current I2, for example, reduces the above-mentioned voltage variation ⁇ V, so as to adjust the output voltage of the voltage output terminal Vout of the power conversion circuit 302 to a correct value.
  • the purpose of the voltage value is the purpose of the voltage value.
  • the voltage output terminal Vout of the power conversion circuit 302 can continuously output the correct supply voltage VLED to the second terminal a of each light string group 21 .
  • the control method of the backlight control circuit provided in the embodiments of the present application also It includes a method of detecting the open circuit of the light string 200.
  • control method further includes:
  • the comparator 311 in the drive circuit 301 After the first current I1 (ie sink current) provided by the feedback signal terminal FBO of the drive circuit 301 is continuously increased by the current change ⁇ I in a stepwise manner, the comparator 311 in the drive circuit 301 still determines When the voltage Vch of any channel port CH is less than the first preset voltage VL, the feedback signal terminal FBO of the driving circuit 301 is in a high impedance state. At this time, it is considered that the light string group 21 has an open circuit state, and at least one light string 200 in the light string group 21 is damaged. Where S ⁇ 2, S is a positive integer.
  • the feedback signal terminal FBO is in a high impedance state, which means that the current of the feedback signal terminal FBO is completely released, so that the feedback signal terminal FBO has a large impedance relative to the reference ground, for example, it can be several hundred K ⁇ , which is the above High resistance state. At this time, the feedback signal terminal FBO will no longer affect the power conversion circuit 302.
  • the comparator 311 in the driving circuit 301 continues to detect the voltage Vch of all the channel ports every frame
  • the comparator 311 in the driving circuit 301 continuously detects that the voltage Vch of any channel port is less than the first preset voltage VL (for example, the feedback signal terminal FBO outputs the first current I1
  • S The second is S ⁇ 2 frames, that is, the comparator 311 detects that the voltage Vch of any channel port is less than the first preset piezoelectric VL for S ⁇ 2 consecutive frames, and the feedback signal terminal FBO of the driving circuit 301 provides the first current I1 (ie (Sinking current) continuously S times in a stepwise manner, for example, increasing the current change amount ⁇ I 8 times, and the current value of the first current I1 provided by the feedback signal terminal FBO of the driving circuit 301 for the third time is 8 ⁇ I.
  • the power conversion circuit 302 increases the voltage output from the voltage output terminal Vout by the voltage change amount ⁇ V each time according to the first current I1.
  • the supply voltage VLED output by the voltage output terminal Vout for the third time is increased by 8 ⁇ V on the basis of the original voltage value.
  • the voltage output terminal Vout of the power conversion circuit 302 outputs the final voltage value (VLED+S ⁇ V) after S times of raising.
  • the comparator 311 in the driving circuit 301 still determines that the voltage Vch of any channel port CH is less than the first preset voltage VL, the feedback signal terminal FBO of the driving circuit 301 is in a high impedance state.
  • the driving circuit 301 can output an open circuit signal to the control system of the display terminal to prompt that there is a light string 200 in an open circuit state in the plurality of light string groups 21, so as to achieve the purpose of open circuit detection.
  • the driving circuit 301 can output an open-circuit signal to the control system of the display terminal, in order to prevent the power supply voltage VLED output by the voltage output terminal Vout of the power conversion circuit 302 from continuing to increase, which may affect other normal light strings 200.
  • the voltage output terminal Vout of the power conversion circuit 302 returns to the initial voltage Vref.
  • the fifth stage E shown in FIG. 9 can be directly entered, and the voltage output terminal Vout of the power conversion circuit 302 is restored to the initial voltage Vref.
  • a fourth stage D may be added between the third stage B and the fifth stage E.
  • the voltage output terminal Vout of the power conversion circuit 302 will keep outputting the voltage value (VLED+(S+1) ⁇ V) after S+1 times of raising.
  • the comparator 311 in the driving circuit 301 still determines that the voltage Vch of any channel port CH is less than the first preset voltage VL, the feedback signal terminal FBO of the driving circuit 301 In a high-impedance state.
  • the fourth stage D by increasing the fourth stage D, the number of times of determining the magnitude of the voltage Vch of the channel port CH is increased, so as to reduce the probability of misjudgment of the magnitude of the voltage Vch of the channel port CH.
  • the fifth stage E shown in FIG. 9 can be entered, and the voltage output terminal Vout of the power conversion circuit 302 is restored to the initial voltage Vref.
  • the present application does not limit the duration of the fourth stage D.
  • the fourth stage D may include three frames or two frames.
  • the feedback signal terminal FBO of the driving circuit 301 will continue to be in a high impedance state, and the voltage output terminal Vout of the power conversion circuit 302 will continue to output the initial voltage Vref, so that each light string 200 in each light string group 21 works at Under the initial voltage Vref.
  • control system of the display terminal 01 when the control system of the display terminal 01 receives the above-mentioned open circuit signal, it can display an alarm message to the user.
  • the user can judge by himself whether the open light string 200 needs to be repaired according to the display effect of the current display terminal 01.
  • this application does not limit the value of the initial voltage Vref.
  • the initial value of the operating voltage required by the light string group 21 where the light string 200 is located, that is, the initial voltage Vref may be about 18V (6 ⁇ 3V).

Abstract

一种背光控制电路及其控制方法、显示终端（01），涉及显示技术领域，用于减少驱动芯片中各个端口电压的差异，减小驱动芯片功耗。背光控制电路包括驱动电路（301）和电源转换电路（302）。其中，驱动电路（301）具有反馈信号端（FBO）和至少一个通道端口（CH1、CH2）。通道端口（CH1、CH2）与灯串组（21）的第一端耦接。驱动电路（301）用于获取各个通道端口（CH1、CH2）的电压（Vch），并基于电压（Vch）反馈信号端（FBO）提供电流反馈信号。电源转换电路（302）与反馈信号端（FBO）耦接，且具有电压输出端（Vout）。电压输出端（Vout）用于向每个灯串组（21）的第二端提供供电电压（VLED）。电源转换电路（302）用于输入电压进行电压转换，并根据电流反馈信号，增大或减小供电电压（VLED）。

Description

一种背光控制电路及其控制方法、显示终端
本申请要求于2019年10月31日提交国家知识产权局、申请号为201911055090.3、申请名称为“一种背光控制电路及其控制方法、显示终端”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及显示技术领域，尤其涉及一种背光控制电路及其控制方法、显示终端。
背景技术
液晶显示装置(liquid crystal display，LCD)，因其具有体积小、功耗低、无辐射以及制作成本相对较低等特点，而越来越多地被应用于高性能显示领域当中。LCD包括液晶显示面板以及用于向该液晶显示面板提供光源的背光模组。相对于侧入式背光模组而言，直下式背光模组可以进行区域控制亮度，具有更好的显示效果。
目前，直下式背光模组中包括多个灯串以及与灯串耦接的驱动芯片。然而LCD在显示的过程中，灯串的前向电压(forward voltage，VF)，即额定电流下对应的电压，会随着温度的变化而变化。从而使得驱动芯片中与各个灯串耦接的端口的电压值发生变化，且存在端口电压值不一致的现象，若端口电压比较大，会导致该驱动芯片的功耗较大。
发明内容
本申请实施例提供一种背光控制电路及其控制方法、显示终端，用于减小驱动芯片中各个端口电压的差异，使其工作在一个合理的工作区间，降低功耗提高效率。
为达到上述目的，本申请采用如下技术方案：
本申请实施例的一方面，提供一种背光控制电路。该用于背光控制电路驱动至少一个灯串组。灯串组包括多个并联的灯串。此外，背光控制电路包括驱动电路和电源转换电路。其中，驱动电路具有反馈信号端和至少一个通道端口；通道端口与灯串组的第一端耦接；驱动电路用于获取各个通道端口的电压Vch，并基于该电压Vch由反馈信号端提供电流反馈信号。电源转换电路与反馈信号端耦接，且具有电压输出端。电压输出端用于向每个灯串组的第二端提供供电电压。电源转换电路用于对输入电压进行电压转换，并根据电流反馈信号，增大或减小上述供电电压。从而使得驱动电路各个通道端口电压Vch能够保持在一定范围之内，避免灯串组的第一端的电压小于通道端口的转折电压或拐点电压，导致灯串组发光亮度不正常，或者，避免灯串组的第一端的电压太大，导致驱动电路的功耗上升。综上所述，一方面，本申请实施例提供上述背光控制电路中，通过在驱动电路上设置能够提供电流反馈信号的反馈信号端，并将该反馈信号端口与电源转换电路耦接。可以使得驱动电路能够实时得根据其各个通道端口的电压Vch向电源转换电路提供电流反馈信号。基于此，电源转换电路能够根据该电流反馈信号实时得对其电压输出端输出的供电电压进行双向调整，即增大该供电电压或者减小该供电电压。这样一来，在显示终端显示的过程中，通灯串组第二 端接收到的供电电压，可以在一定范围内进行调整，从而可以避免驱动电路的各个通道端口的电压Vch长时间保持较高或较低的状态，并能够减小驱动电路的各个通道端口的电压Vch1之间的差异，最终达到减小驱动电路功耗的目的。另一方面，由于驱动电路与电源转换电路耦接的反馈信号端口提供的反馈信号为电流反馈信号。该电流信号相对于电压信号而言，不会受到驱动电路与电源转换电路之间距离的影响而产生较大的波动，从而可以减小走线噪声带来的信号干扰。
可选的，驱动电路具体用于将各个通道端口的电压Vch与第一预设电压VL和第二预设电压VH进行比对。其中，VL＜VH。此外，该驱动电路具体还用于当任意一个通道端口的电压Vch小于第一预设电压VL时，由反馈信号端提供第一电流I1作为电流反馈信号，该第一电流I1用于增大上述供电电压。当所有通道端口的电压Vch均大于第二预设电压VH时，由反馈信号端提供第二电流I2作为电流反馈信号，该第二电流I2用于减小所述供电电压。其中，第一电流I1和第二电流I2方向相反。综上所述，驱动电路的反馈信号端即可以提供第一电流I1(即灌电流)，以抬升电源转换电路的电压输出端输出的供电电压，驱动电路的反馈信号端又可以提供第二电流I2(即拉电流)，以减小电源转换电路的电压输出端输出的供电电压。因此本申请实施例提供的背光控制电路能够对灯串组第二端的电压进行双向调节。
可选的，驱动电路包括比较器、第一电流源以及第二电流源。其中，比较器的输入端与通道端口相连接，比较器的第一输出端与第一电流源的控制端相耦接，此外，比较器的第二输出端与第二电流源的控制端相耦接。比较器用于将各个通道端口的电压Vch与第一预设电压VL和第二预设电压VH进行比对，且当任意一个通道端口的电压Vch小于第一预设电压VL时，第一输出端输出第一控制信号；当所有通道端口的电压Vch均大于第二预设电压VH时，第二输出端输出第二控制信号。其中，VL＜VH。第一电流源的第一极耦接反馈信号端，第二极耦接第一电压端。第一电流源用于接收上述第一控制信号，反馈信号端提供第一电流I1。此外，第二电流源的第一极耦接第二电压端，第二极耦接反馈信号端。第二电流源用于接收所述第二控制信号，反馈信号端提供第二电流I2。其中，第一电压端用于输出第一电压V1，第二电压端用于输出第二电压V2，|V1|＜|V2|。该驱动电路的反馈信号端即可以提供第一电流I1(即灌电流)，又可以提供第二电流I2(即拉电流)的技术效果同上所述，此处不再赘述。
可选的，电源转换电路包括第一电阻，具有阻值R1。第一电阻的第一端与电压输出端相耦接，第一电阻的第二端与反馈信号端相耦接。
可选的，背光控制电路还包括第二电阻。该第二电阻的第一端与第一电阻的第二端相耦接，第二电阻的第二端与驱动电路的反馈信号端相耦接。第二电阻用于对第一电阻的第二端和反馈信号端进行阻抗匹配。
可选的，驱动电路还具体用于当任意一个通道端口的电压Vch连续S次小于第一预设电压VL时，由反馈信号端提供的第一电流I1以步进的方式连续S次增加电流变化量△I。其中，S≥2，S为正整数。此外，电源转换电路还具体用于每次根据第一电流I1，将电压输出端的电压增加电压变化量△V。在此情况下，驱动电路可以持续每一帧对所有通道端口的电压Vch进行检测的情况下，当驱动电路连续S次检测到任意一个通道端口的电压Vch小于第一预设电压VL时(例如反馈信号端每两帧输出一次第 一电流I1，S次的时长为S×2帧，即驱动电路连续S×2帧检测到任意一个通道端口的电压Vch小于第一预设压电VL)，反馈信号端提供的第一电流I1会以步进的方式连续S次增加电流变化量△I，所以第S次反馈信号端提供的第一电流I1的电流值为S×△I。电源转换电路每次根据第一电流I1，将电压输出端的电压增加电压变化量△V，所以第S次电源转换电路的电压输出端Vout输出的电压在原有电压的基础上增加了S×△V。此外，上述电压变化量△V1＝|△I|×R1。这样一来，可以通过调节第一电阻的阻值，对上述电压变化量△V的大小进行调节。
可选的，驱动电路还具体用于当反馈信号端提供的第一电流I1以步进的方式连续S次增加电流变化量△I后，判断出任意一个通道端口的电压Vch小于第一预设电压VL时，反馈信号端处于高阻态。由于多个灯串组中存在处于开路状态的灯串，所以无论电源转换电路的电压输出端输出的供电电压的电压值如何上调，处于开路的灯串的第二端所耦接的通道端口的电压仍然小于第一预设压电VL。此时，驱动电路可以向显示终端的控制系统输出开路信号，以达到开路检测的目的。
可选的，驱动电路还具体用于当所有通道端口的电压Vch连续N次均大于第二预设电压VH时，由反馈信号端提供的第二电流I2以步进的方式连续N次减小电流变化量△I。其中，N≥2；N为正整数。电源转换电路还具体用于每次根据第二电流I1，将电压输出端的电压减小电压变化量△V。
在此情况下，驱动电路可以持续每一帧对所有通道端口的电压Vch进行检测的情况下，当驱动电路检测到所有通道端口的电压Vch连续N次均大于第二预设电压VH时，反馈信号端提供的第二电流I2会以步进的方式连续N次减小电流变化量△I，所以第N次反馈信号端提供的第二电流I2的电流值为N×△I。电源转换电路每次根据第二电流I2，将电压输出端的电压减小电压变化量△V，所以第N次电源转换电路的电压输出端Vout输出的电压在原有电压的基础上减小N×△V。此外。电压变化量△V1＝|△I|×R1。第一电阻R1的技术效果同上所述，此处不再赘述。
可选的，驱动电路还具有多个选通端口和与每个选通端口耦接的一个供电端口，供电端口还与电源转换电路的电压输出端相耦接。多个灯串组阵列排布；同一行的多个灯串组的第二端与一个选通端口相耦接；同一列的灯串组的第一端与驱动电路的一个通道端口相耦接。这样一来，一个通道端口可以分别与同一列的灯串组的第一端，因此能够减小驱动电路中通道端口的数量。
可选的，电源转换电路的电压输出端与每个灯串组的第一端相耦接。这样一来，电源转换电路的电压输出端可以同向灯串组的第二端提供上述供电电压。
本申请实施例的另一方面，提供一种背光控制电路的控制方法。该背光控制电路用于驱动至少一个灯串组。灯串组包括多个并联的灯串。背光控制电路包括驱动电路和电源转换电路。驱动电路具有反馈信号端和至少一个通道端口。通道端口与灯串组的第一端耦接。电源转换电路与反馈信号端耦接，且具有电压输出端。此外，上述控制方法包括：首先，驱动电路获取通道端口的电压Vch，并基于上述电压Vch由反馈信号端提供电流反馈信号。接下来，电源转换电路根据电流反馈信号，增大或减小电压输出端的供电电压。该背光控制电路的控制方法具有与前述实施例提供的背光控制电路相同的技术效果，此处不再赘述。
可选的，驱动电路获取通道端口的电压Vch，并提供电流反馈信号具体包括：首先，驱动电路将各个通道端口的电压Vch与第一预设电压VL和第二预设电压VH进行比对；其中，VL＜VH。接下来，当任意一个通道端口的电压Vch小于第一预设电压VL时，驱动电路的反馈信号端提供第一电流I1作为电流反馈信号，该第一电流I1用于增大供电电压。或者，当所有通道端口的电压Vch均大于第二预设电压时，驱动电路的反馈信号端提供第二电流I2作为电流反馈信号，该第二电流I2用于减小供电电压。其中，第一电流I1和第二电流I2方向相反。该驱动电路的反馈信号端即可以提供第一电流I1(即灌电流)，又可以提供第二电流I2(即拉电流)的技术效果同上所述，此处不再赘述。
可选的，驱动电路包括比较器、第一电流源以及第二电流源。比较器的输入端与通道端口相连接。比较器的第一输出端与第一电流源的控制端相耦接。第一电流源的第一极耦接反馈信号端，第二极耦接第一电压端。比较器的第二输出端与第二电流源的控制端相耦接。第二电流源的第一极耦接第二电压端，第二极耦接反馈信号端。其中，第一电压端用于输出第一电压V1，第二电压端用于输出第二电压V2，|V1|＜|V2|。基于此，驱动电路获取通道端口的电压Vch，并提供电流反馈信号具体包括：首先，比较器将各个通道端口的电压Vch与第一预设电压VL和第二预设电压VH进行比对。其中，VL＜VH。接下来，当任意一个通道端口的电压Vch小于第一预设电压V时，比较器的第一输出端输出第一控制信号，第一电流源接收该第一控制信号，反馈信号端提供第一电流I1。或者，当所有通道端口的电压Vch均大于第二预设电压时，比较器的第二输出端输出第二控制信号，第二电流源接收上述第二控制信号，反馈信号端提供第二电流I2。该驱动电路的反馈信号端即可以提供第一电流I1(即灌电流)，又可以提供第二电流I2(即拉电流)的技术效果同上所述，此处不再赘述。
可选的，电源转换电路包括第一电阻，具有阻值R1。第一电阻的第一端与电压输出端相耦接，第一电阻的第二端与反馈信号端相耦接。驱动电路获取通道端口的电压Vch，并基于电压Vch由反馈信号端提供电流反馈信号包括当任意一个通道端口的电压Vch连续S次小于第一预设电压VL时，由反馈信号端提供的第一电流I1以步进的方式连续S次增加电流变化量△I。其中，S≥2，S为正整数。电源转换电路根据电流反馈信号，增大或减小电压输出端的供电电压包括电源转换电路每次根据第一电流I1，将电压输出端的电压增加电压变化量△V；电压变化量△V1＝|△I|×R1。驱动电路、电源转换电路以及第一电阻的技术效果同上所述，此处不再赘述。
可选的，方法还包括：首先，当驱动电路的反馈信号端提供的第一电流I1以步进的方式连续S次增加电流变化量△I后，判断出任意一个通道端口的电压Vch小于第一预设电压V时，驱动电路的反馈信号端处于高阻态电源转换电路。接下来，电源转换电路的电压输出端的电压恢复至初始电压。通过上述方法实现开路检测的技术效果同上所述，此处不再赘述。
可选的，电源转换电路包括第一电阻，具有阻值R1。第一电阻的第一端与电压输出端相耦接，第一电阻的第二端与反馈信号端相耦接。驱动电路获取通道端口的电压Vch，并基于电压Vch由反馈信号端提供电流反馈信号包括：当所有通道端口的电压Vch连续N次均大于第二预设电压VH时，由反馈信号端提供的第二电流I2以步进的 方式连续N次减小电流变化量△I。其中，N≥2；N为正整数。电源转换电路根据电流反馈信号，增大或减小电压输出端的供电电压包括：电源转换电路每次根据第二电流I1，将电压输出端的电压减小电压变化量△V。电压变化量△V1＝|△I|×R1。驱动电路、电源转换电路以及第一电阻的技术效果同上所述，此处不再赘述。
本申请实施例的另一方面，提供一种显示终端，包括液晶显示面板用于向液晶显示面板提供光源的背光模组。背光模组包括多个灯串组和背光控制电路。灯串组包括多个并联的灯串；每个灯串包括多个串联的发光器件。此外，背光控制电路包括驱动电路和电源转换电路。其中，该驱动电路具有反馈信号端和至少一个通道端口。通道端口与灯串组的第一端耦接；驱动电路用于获取各个通道端口的电压Vch，并基于上述电压Vch由反馈信号端提供电流反馈信号。电源转换电路，与反馈信号端耦接，且具有电压输出端。电压输出端用于向每个灯串组的第二端提供供电电压。电源转换电路用于根据电流反馈信号，增大或减小电压输出端的供电电压。该显示终端具有与前述实施例提供的背光控制电路相同的技术效果，此处不再赘述。
可选的，液晶显示面板包括多个阵列排布的亚像素。多个灯串组阵列排布。M×N个亚像素所在的区域在背光模组的垂直投影，与一个灯串组所在的区域重叠；其中，M≥1，N≥1，N、M为正整数。这样一来，驱动电路的一个通道端口可以控制至少一个灯串组的亮度，从而无需单独控制每个灯串的亮度。而该灯串组所在的区域可以与液晶显示面板中M×N个亚像素所在的区域相对应，从而可以达到对显示终端显示的画面进行区域调光的目的。
可选的，驱动电路还具有多个选通端口和与每个选通端口耦接的供电端口，供电端口还与电源转换电路的电压输出端相耦接。该背光模组还包括多个第二信号线和第一信号线。一条第二信号线分别与同一行的多个灯串组的第二端，以及一个选通端口相耦接。一条第一信号线分别与同一列的灯串组的第一端，以及驱动电路的一个通道端口相耦接。这样一来，驱动电路的供电端口可以逐一向每个选通端口提供供电电压。此外，上述多条第一信号线可以逐行将同一行的各个灯串组的第一端的电压，分别传输至各个通道端口。在此情况下，驱动电路可以用于获取各个通道端口的电压，并根据各个通道端口的电压的大小，生成电流反馈信号。此外，一个通道端口可以分别与同一列的灯串组的第一端，因此能够减小驱动电路中通道端口的数量。
本申请实施例的另一方面，提供一种驱动电路。该驱动电路具有反馈信号端和至少一个通道端口。其中，通道端口与灯串组的第一端耦接。驱动电路用于获取各个通道端口的电压Vch，并基于电压Vch由反馈信号端提供电流反馈信号给电源转换电路，以使得电源转换电路根据电流反馈信号，增大或减小输出电压。该驱动电路的技术效果同上所述，此处不再赘述。
可选的，驱动电路具体用于将各个通道端口的电压Vch与第一预设电压VL和第二预设电压VH进行比对。其中，VL＜VH。此外，该驱动电路具体还用于当任意一个通道端口的电压Vch小于第一预设电压VL时，由反馈信号端提供第一电流I1作为电流反馈信号，该第一电流I1用于增大上述供电电压。当所有通道端口的电压Vch均大于第二预设电压VH时，由反馈信号端提供第二电流I2作为电流反馈信号，该第二电流I2用于减小所述供电电压。其中，第一电流I1和第二电流I2方向相反。第一 电流I1和第二电流I2的技术效果同上所述，此处不再赘述。
可选的，驱动电路包括比较器、第一电流源以及第二电流源。其中，比较器的输入端与通道端口相连接，比较器的第一输出端与第一电流源的控制端相耦接，此外，比较器的第二输出端与第二电流源的控制端相耦接。比较器用于将各个通道端口的电压Vch与第一预设电压VL和第二预设电压VH进行比对，且当任意一个通道端口的电压Vch小于第一预设电压VL时，第一输出端输出第一控制信号；当所有通道端口的电压Vch均大于第二预设电压VH时，第二输出端输出第二控制信号。其中，VL＜VH。第一电流源的第一极耦接反馈信号端，第二极耦接第一电压端。第一电流源用于接收上述第一控制信号，反馈信号端提供第一电流I1。此外，第二电流源的第一极耦接第二电压端，第二极耦接反馈信号端。第二电流源用于接收所述第二控制信号，反馈信号端提供第二电流I2。其中，第一电压端用于输出第一电压V1，第二电压端用于输出第二电压V2，|V1|＜|V2|。该驱动电路的反馈信号端即可以提供第一电流I1(即灌电流)，又可以提供第二电流I2(即拉电流)的技术效果同上所述，此处不再赘述。
附图说明
图1为本申请实施例提供的一种显示终端的结构示意图；
图2a为本申请实施例提供的多个灯串组的结构示意图；
图2b为图2a所示的灯串组与亚像素的对应关系示意图；
图3a为本申请实施例提供的背光控制电路与多个灯串组的一种连接关系示意图；
图3b为本申请实施例提供的背光控制电路与多个灯串组的另一种连接关系示意图；
图3c为本申请实施例提供的背光控制电路与多个灯串组的另一种连接关系示意图；
图4a为本申请实施例提供的温度与灯串的前向电压的关系示意图；
图4b为图3a中各个通道端口的电压值示意图；
图5为本申请实施例提供的一种背光控制电路的控制方法流程图；
图6为图5中S101的具体步骤流程图；
图7为本申请实施例提供的驱动电路、电源转换电路以及多个灯串组的一种连接示意图；
图8为本申请实施例提供的驱动电路、电源转换电路以及多个灯串组的另一种连接示意图；
图9为本申请实施例提供的电源转换电路的电压输出端在不同阶段输出电压的示意图。
附图标记：
01-显示终端；10-液晶显示面板；100-对盒基板；101-阵列基板；102-液晶层；20-背光模组；201-反射片；202-发光器件；203-光学膜片；02-中框；21-灯串组；200-灯串；120-亚像素；30-背光控制电路；301-驱动电路；302-电源转换电路；323-发光控制电流源；311-比较器；321-第一电流源；322-第二电流源。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行描述，显 然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。
以下，术语“第一”、“第二”等仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”等的特征可以明示或者隐含地包括一个或者更多个该特征。在本申请的描述中，除非另有说明，“多个”的含义是两个或两个以上。
此外，本申请中，“上”、“下”、“左”、“右”等方位术语可以包括但不限于相对附图中的部件示意置放的方位来定义的，应当理解到，这些方向性术语可以是相对的概念，它们用于相对于的描述和澄清，其可以根据附图中部件附图所放置的方位的变化而相应地发生变化。
在本申请中，术语“耦接”可以是实现信号传输的电性连接的方式。除非另有明确的规定和限定，“耦接”可以是直接电性连接，也可以通过中间媒介间接电性连接。
本申请实施例提供一种显示终端。该显示终端包括例如电视、手机、平板电脑、个人数字助理(personal digital assistant，PDA)、车载电脑等。本申请实施例对上述显示终端的具体形式不做特殊限制。上述任意一种形式的显示终端包括LCD。在此情况下，如图1所示，显示终端01包括液晶显示面板10以及背光模组(backlight unit，BLU)20。
液晶显示面板10如图1所示，包括相对设置的对盒基板100和阵列基板101。对盒基板100和阵列基板101对盒形成液晶盒。该液晶显示面板10还具有填充于对盒基板100和阵列基板101之间的液晶层102。通过控制背光模组20发出的光线经过液晶显示面板10后的光线透过率，达到控制该显示灰阶的目的。
上述背光模组20如图1所示，包括反射片201、设置于该反射片201上的多个发光器件202以及位于该发光器件202出光侧的多层光学膜片203。上述光学模块203可以为扩散片、棱镜片等。
上述发光器件202可以为发光二极管(light emitting diode，LED)。基于此，多个发光器件202可以串联构成如图2a所示的灯串200。多个灯串200并联可以构成一个灯串组21。一个灯串组21可以作为一个能够单独进行亮度控制的背光控制区域，从而实现对背光模组20的区域调光(local dimming)，以达到增强画面对比度的目的。
在本申请的一些实施例中，如图2b所示，液晶显示面板10中的多个亚像素120阵列排布。背光模组20中的多个灯串组21也阵列排布。基于此，M×N个亚像素120所在的区域在背光模组20上的垂直投影，与一个灯串组21所在的区域重叠。即当对一个灯串组21的发光亮度进行控制时，可以控制M×N个亚像素120所在的区域的显示亮度。
其中，M≥1，N≥1，N、M为正整数。当M、N的数量越小，背光模组20区域调光的精度越高，控制过程越复杂。反之，当M、N的数量越大，背光模组20区域调光的精度越低，控制过程越简单。本申请对N、M的具体数值不做限定。
需要说明的是，以下为了方便说明，将图2a所示的阵列排布的多个灯串组21中，沿X方向排布的一排灯串组21称为同一行灯串组21，沿Y方向排布的一排灯串组21称为同一列灯串组21。
为了对上述多个灯串组21进行控制，本申请实施例提供的显示终端01还包括如 图3a所示的背光控制电路30。该背光控电路30包括驱动电路301和电源转换电路302。上述背光控制电路30可以设置于背光模组20远离液晶显示面板10一侧的中框02(如图1所示)上。该中框02背离液晶显示面板10的一侧还设置有显示终端01的主板。在本申请的一些实施例中，上述背光控制电路30可以集成于主板上。或者，在另一些实施例中，背光控制电路30和主板可以在中框02上独立设置。又或者，在另一些实施例中，背光控制电路30可以集成于背光模组20内部。
此外，驱动电路301可以为驱动芯片(integrated circuit，IC)。电源转换电路302可以为直流(direct current，DC)转直流，即DC/DC直流电源芯片。该DC/DC直流电源芯片的输入端Vin(如图3a所示)用于接收一输入电压，并对该输入电压进行电压转换作为输出电压。
示例的，显示终端01的电池电压或者其他电源电路的输出，都可以作为该DC/DC直流电源芯片的输入。同时，DC/DC直流电源芯片的输入需要考虑作为负载的灯串组21的负载功耗，且DC/DC直流电源芯片的输入还需要满足灯串组21的瞬态性能要求。在此情况下，当电源转换电路302接收到的输入电压的幅值较小时，电源转换电路302可以作为升压电路，对输入电压进行升压处理。从而可以从电源转换电路302的电压输出端Vout，输出能够使得灯串组21中的各个灯串200正常发光的供电电压VLED。
或者，当输入电压的幅值较大时，电源转换电路302可以作为降压电路，对输入电压进行降压处理，以输出从其电压输出端Vout输出上述供电电压VLED。
例如，一个灯串200上的一个发光器件202在正常发光时需要3V左右的电压。当一个灯串200上串联有10个发光器件202时，该灯串200的第二端a需要的供电电压VLED＝30V。此时，上述电源转换电路302可以将输入端Vin接收到的输入电压转换成30V的供电电压。
此外，如图3a所示，上述驱动电路301具有反馈信号端(feedback output，FBO)和至少一个通道端口(例如图3a中的CH1、CH2……)。其中，一个通道端口与至少一个灯串组21的第一端c(即该灯串组21中每一串灯串200的阴极)耦接。
在此情况下，该驱动电路301内部可以设置与上述各个通道端口(例如图3a中的CH1、CH2……)分别耦接的如图3b所示的发光控制电流源323。该发光控制电流源323可以向与该发光控制电流源323耦接的通道端口CH提供恒定的拉电流。上述拉电流通过通道端口CH传输至该通道端口耦接的灯串组21中并联的每个灯串200中，从而能够驱动该灯串组21中每个灯串200的发光。
需要说明的是，流过灯串组21的额定电流与通道端口CH的转折电压或拐点电压(knee voltage)相匹配。当驱动电路301的通道端口CH的电压小于上述转折电压时，与该通道端口CH耦接的发光控制电流源323无法向灯串组21提供上述额定电流，灯串组21无法正常发光。因此，为了使得灯串组21能够发光亮度正常，通道端口CH的电压需要大于通道端口CH的转折电压。
基于此，为了对每个灯串200的发光亮度进行调节，可以利用占空比可调的脉宽调制(pulse width modulation，PWM)信号，根据发光亮度的需求，对PWM信号的占空比进行调节，从而能够对发光控制电流源323在一定时间内向灯串组21提供的拉电流的有效时长进行控制，达到控制灯串组21发光亮度的目的。
这样一来，驱动电路301的一个通道端口可以耦接至少一个灯串组21，从而无需将每个灯串200与一个通道端口相耦接。由上述可知，该灯串组21所在的区域可以与液晶显示面板10中M×N个亚像素120所在的区域相对应，从而可以达到对显示终端01显示的画面进行区域调光的目的。可以理解地，也可以每个灯串200与一个通道端口相耦接，这样需要在驱动电路301上提供更多的通道端口。
此外，如图3a所示，上述背光控电路30中的电源转换电路302可以与驱动电路301的反馈信号端FBO耦接。并且，该电源转换电路302具有电压输出端Vout。该电压输出端Vout用于向每个灯串组21的第二端a(即该灯串组21中每一串灯串200的阳极)提供供电电压VLED。
在本申请的一些实施例中，在背光模组20还包括如图3a所示的多条第一信号线SLc的情况下，上述通道端口(CH1、CH2……)与各个灯串组21的连接方式可以为，一条第一信号线SLc分别与同一列(Y方向)的灯串组21的第一端c，以及驱动电路301的一个通道端口CH相耦接。
此外，背光模组20还包括如图3a所示的多条第二信号线SLa，驱动电路301还具有多个选通端口(SW1、SW2……)和与每个选通端口(SW1、SW2……)耦接的供电端口Vps。该供电端口Vps还与电源转换电路302的电压输出端Vout相耦接。从而使得电源转换电路302的电压输出端Vout能够将上述供电电压VLED传输至驱动电路301的供电端口Vps。
基于此，电源转换电路302向每个灯串组21的第二端a提供供电电压VLED的方式可以，如图3a所示，一条第二信号线SLa分别与同一行(X方向)的多个灯串组21的第二端a，以及一个选通端口SW1相耦接。
这样一来，驱动电路301的供电端口Vps可以逐一向每个选通端口(SW1、SW2……)提供供电电压VLED。此外，上述多条第一信号线SLc可以逐行将同一行(X方向)的各个灯串组21的第一端c的电压，分别传输至各个通道端口(CH1、CH2……)。在此情况下，驱动电路301可以用于获取各个通道端口(CH1、CH2……)的电压(Vch1、Vch2……)，并基于上述电压(Vch1、Vch2……)的大小，生成电流反馈信号。该电流反馈信号可以由驱动电路301的反馈信号端FBO提供至电源转换电路302。
或者，在本申请的另一些实施例中，如图3c所示，上述通道端口(CH1、CH2……)与各个灯串组21的连接方式可以为，一条第一信号线SLc与一个灯串组21的第一端c耦接。在此情况下，相对于图3c所示的结构而言，由于图3a中，一个通道端口CH可以分别与同一列(Y方向)的灯串组21的第一端c，因此能够减小驱动电路301中通道端口CH的数量。
此外，在驱动电路301的各个通道端口(CH1、CH2……)与各个灯串组21的连接方式如图3c所示时，电源转换电路302的电压输出端Vout可以直接与各行的灯串组21的第二端a相耦接。在此情况下，当电源转换电路302的电压输出端Vout输出供电电压VLED后，驱动电路301可以直接获取各个通道端口(CH1、CH2……)的电压(Vch1、Vch2……)，并由反馈信号端FBO提供电流反馈信号。
为了方便说明，以下均是以图3a所示的结构为例对背光控电路30进行的说明。
此外，上述各个灯串组21中的灯串200的前向电压VF，如图4a所示会随着灯串 200自身温度的升高而降低。其中，图4a为灯串200的额定工作电流IF＝3mA的情况下，灯串200的温度与前向电压VF的曲线变化图。
由于显示终端01显示的画面中各处的亮度不同，使得位置不同的灯串组21的温度也不同，这样一来导致驱动电路301的各个通道端口(CH1、CH2……)的电压(Vch1、Vch2……)如图4b所示存在不一致的现象。其中，图4b中条状图形的高度越大表示该通道端口的电压值越大。
基于此，由上述可知，电源转换电路302与驱动电路301的反馈信号端FBO耦接。因此电源转换电路302在将输入电压进行电压转换后，还可以用于根据驱动电路301的反馈信号端FBO提供的电流反馈信号，对转换后的电压进行微调后得到上述供电电压VLED，并通过电压输出端Vout输出。从而达到对灯串组21的第二端a的电压进行调节的目的。
这样一来，当对灯串组21的第二端a的电压调节后，由于流过灯串组21的拉电流固定不变，因此灯串组21的第二端a的电压，即上述驱动电路301的各个通道端口(CH1、CH2……)的电压(Vch1、Vch2……)会跟随灯串组21的第二端a的电压的变化而变化，以使得灯串组21的第一端c的电压大于驱动电路301的通道端口CH的转折电压，从而确保可灯串组21能够发光亮度正常。此外，还使得驱动电路301各个通道端口电压Vch能够保持在一定范围之内，进而在保证灯串组21发光亮度正常的同时，降低驱动电路的功耗。
由于灯串组21的前向电压VF为灯串组21第二端的电压Va与其第一端的电压Vc的电压差，即，VF＝Va-Vc＝VLED-Vch。因此，示例的，当灯串组21的前向电压VF减小，导致该灯串组21的第一端c耦接的驱动电路301的通道端口CH的电压Vch升高时，驱动电路301会通过向电源转换电路302提供一种电流反馈信号。
此时，电源转换电路302可以根据该电流反馈信号，减小该电源转换电路302的电压输出端Vout输出的供电电压VLED，由于上述发光控制电流源323向流过灯串组21提供的拉电流的大小固定不变，因此灯串组21的第二端a的电压，即驱动电路301中与该灯串组21的第二端a耦接的通道端口CH的电压Vch随之减小。
或者，又示例的，当灯串组21的前向电压VF增大，导致该灯串组21的第一端c耦接的驱动电路301的通道端口CH的电压Vch降低时，驱动电路301会通过向电源转换电路302提供另一种电流反馈信号。
此时，电源转换电路302可以根据该电流反馈信号，增大该电源转换电路302的电压输出端Vout输出的供电电压VLED。由于上述发光控制电流源323向灯串组21体用的拉电流的大小固定不变，因此灯串组21的第二端a的电压，即驱动电路301中与该灯串组21的第二端a耦接的通道端口CH的电压Vch随之增大。
综上所述，一方面，本申请实施例提供上述背光控制电路30中，通过在驱动电路301上设置能够提供电流反馈信号的反馈信号端FBO，并将该反馈信号端口FBO与电源转换电路302耦接。可以使得驱动电路301能够实时得根据其各个通道端口(CH1、CH2……)的电压(Vch1、Vch2……)向电源转换电路302提供电流反馈信号。基于此，电源转换电路302能够根据该电流反馈信号实时得对其电压输出端Vout输出的供电电压VLED进行双向调整。
这样一来，在显示终端01显示的过程中，灯串组21第二端接收到的供电电压VLED，可以在一定范围内(例如，300mV左右)进行调整，避免通道端口CH的电压Vch小于通道端口CH的转折电压，导致灯串组21发光亮度不正常。或者，避免通道端口CH的电压Vch太大，导致驱动电路的功耗上升。此外，还可以避免驱动电路301的各个通道端口(CH1、CH2……)的电压(Vch1、Vch2……)长时间保持较高或较低的状态，并能够减小驱动电路301的各个通道端口(CH1、CH2……)的电压(Vch1、Vch2……)之间的差异，最终达到减小驱动电路301功耗的目的。
另一方面，由于驱动电路301与电源转换电路302耦接的反馈信号端口FBO提供的反馈信号为电流反馈信号。该电流信号相对于电压信号而言，不会受到驱动电路301与电源转换电路302之间距离的影响而产生较大的波动，从而可以减小走线噪声带来的信号干扰。
基于上述背光控制电路30的结构，本申请实施例提供一种背光控制电路的控制方法，如图5所示，包括S101和S102。
S101、驱动电路301获取各个通道端口(CH1、CH2……)的电压(Vch1、Vch2……)，并由反馈信号端FBO提供电流反馈信号。
由上述可知，驱动电路301用于执行上述S101。该S101具体包括如图6所示的S201～S203。
S201、驱动电路301将各个通道端口(CH1、CH2……)的电压(Vch1、Vch2……)与第一预设电压VL和第二预设电压VH进行比对。其中，VL＜VH。
需要说明的是，当通道端口电压Vch位于VL～VH的范围内时，对驱动电路301的功耗影响较小，可以忽略不计。在通道端口电压Vch不在上述VL～VH的范围内的情况下，例如，通道端口电压Vch小于第一预设电压VL时，容易使得通道端口CH的电压Vch小于通道端口CH的转折电压，从而导致灯串组21发光亮度不正常。或者，当通道端口电压Vch大于第二预设电压VH时，通道端口电压Vch对驱动电路301的功耗影响较大。此时，驱动电路301的反馈信号端FBO需要向电源转换电路302提供电流反馈信号，从而使得电源转换电路302能够根据该电流反馈信号，实时得对其电压输出端Vout输出的供电电压VLED进行双向调整，最终将通道端口CH的电压调整至VL～VH的范围内。本申请对第一预设电压VL和第二预设电压VH的数值不做限定，可以根据驱动电路301性能以及能够承受的功耗进行设定。
驱动电路301为了能够执行上述S201，该驱动电路301如图7所示，可以包括比较器311。该比较器311的输入端与各个通道端口CH相耦接。此外，该比较器311还具有两个参考电压输入端，分别用于向比较器311输入第一预设电压VL和第二预设电压VH。
需要说明的是，比较器311与多个通道端口CH相耦接的情况下，示例的，比较器311可以分别连接各个通道端口，将各个通道端口的电压Vch与上述第一预设电压VL和第二预设电压VH进行比对。本申请对比较器311对多个与其耦接的通道端口CH的电压进行比较的方式不做限定。
这样一来，比较器311可以将各个通道端口(CH1、CH2……)的电压(Vch1、Vch2……)与第一预设电压VL和第二预设电压VH进行比对。此外，比较器311还 具有第一输出端O1和第二输出端O2。
其中，为了保证驱动电路301中所有通道端口传输至灯串组21的电流的稳定性，以使得灯串组21的发光性能稳定，从而能够正常发光，当比较器311的比较结果为任意一个通道端口CH的电压Vch小于第一预设电压VL时，即任意一个Vch＜VL时，该比较器311的第一输出端O1输出有效信号。
或者，当比较器311的比较结果为所有通道端口CH的电压Vch均大于第二预设电压VH时，即所有Vch＞VH时，为了减小驱动电路301的功耗，该比较器311的第二输出端O2输出有效信号。
S202、当任意一个通道端口CH的电压Vch小于第一预设电压VL时，由驱动电路301的反馈信号端FBO提供第一电流I1作为电流反馈信号。
需要说明的是，由上述可知，驱动电路301基于各个通道端口的电压(Vch1、Vch2……)由驱动电路301的反馈信号端FBO提供电流反馈信号。在此情况下，在一些实施例中，驱动电路301在执行上述S202的过程中，该驱动电路301中的比较器311可以获取所有通道端口的电压Vch，然后判断每一个通道端口的电压Vch是否小于第一预设电压VL。接下来，根据对所有通道端口的电压Vch的判断结果，获得所有通道端口的电压Vch中是否有任意一个通道端口CH的电压Vch小于第一预设电压VL。
或者，在另一些实施例中，驱动电路301在执行上述S202的过程中，该驱动电路301中的比较器311可以按照各个通道端口CH的物理设置位置，依次判断各个通道端口的电压Vch是否小于第一预设电压VL。当有一个通道端口的电压Vch小于第一预设电压VL时，则认为任意一个通道端口CH的电压Vch小于第一预设电压VL。本申请对驱动电路301如何判断出任意一个通道端口CH的电压Vch小于第一预设电压VL的方式不做限定。
驱动电路301为了能够执行上述S202，该驱动电路301如图7所示，可以包括第一电流源321，该第一电流源321用于执行上述S202。
示例的，如图7所示，第一电流源321的控制端(Con)与比较器311的第一输出端O1相耦接。第一电流源321的第一极(例如正极“+”)耦接驱动电路301的反馈信号端FBO，第二极(例如负极“-”)耦接第一电压端，该第一电压端用于输出第一电压V1。例如，在本申请的一些实施例中，上述第一电压端可以为接地端GND，该第一电压V1为0V或者低电平。
由于第一电流源321的正极“+”耦接驱动电路301的反馈信号端FBO，负极“-”耦接接地端GND，因此该第一电流源321产生的第一电流I1可以为流向驱动电路301的灌电流(sink)。
基于此，当比较器311的比较结果为任意一个通道端口CH的电压Vch小于第一预设电压VL时，该比较器311的第一输出端O1输出有效信号，作为第一控制信号，且当第一电流源321的控制端(Con)接收到上述第一控制信号时开始工作，产生第一电流I1，并作为驱动电路301的反馈信号端FBO提供的电流反馈信号。
需要说明的是，本申请实施例中，该驱动电路301中的比较器311可以每帧对各个通道端口CH的电压Vch进行检测，用户可以根据需要对比较器311的检测结果的 上报时间进行设定，例如上述检测结果可以每帧，或者两帧上报一次。其中，上述一帧可以根据液晶显示面板10中的刷新率进行计算。例如，当液晶显示面板10中的刷新率为60Hz时，一帧的时长T＝1/60Hz。
在驱动电路301中的比较器311每次(例如，一次可以为两帧)上报检测结果的情况后，当驱动电路301根据比较器311上报的检测结果，获得任意一个通道端口的电压Vch连续S次(例如S次为S×2帧，其中，S≥2；S为正整数)小于第一预设电压VL时，驱动电路301的反馈信号端FBO提供的第一电流I1可以步进的方式每次增加电流变化量△I。
需要说明的是，驱动电路301的反馈信号端FBO提供的第一电流I1以步进的方式每次增加电流变化量△I是指，驱动电路301的反馈信号端FBO每次提供的第一电流I1的电流值，会在上一次提供的第一电流I1的电流值的基础上增加电流变化量△I。
接下来，执行如图5所示的S102。
S102、电源转换电路302根据上述电流反馈信号，增大电压输出端Vout的供电电压VLED。
由上述可知，当任意一个通道端口CH的电压Vch小于第一预设电压VL时，由驱动电路301的反馈信号端FBO提供第一电流I1作为上述电流反馈信号。在上述多个灯串组21、电源转换电路302以及驱动电路301构成的回路中，由于第一电流I1为流向驱动电路301的灌电流，因此根据电流由高电势流向低电势的特性，电源转换电路302的电压输出端Vout，输出的供电电压VLED会在原有电压大小的基础上增大。
基于此，在当任意一个通道端口的电压Vch连续S次(如S次为S×2帧，其中，S≥2；S为正整数)小于第一预设电压VL时，驱动电路301的反馈信号端FBO提供的第一电流I1以步进的方式每次增加电流变化量△I的情况下，在上述多个灯串组21、电源转换电路302以及驱动电路301构成的回路中，由于第一电流I1为流向驱动电路301的灌电流，因此根据电流由高电势流向低电势的特性，电源转换电路302每次根据第一电流I1，将电压输出端Vout的电压，即供电电压VLED增加电压变化量△V。
这样一来，当任意一个所述通道端口的电压Vch连续S次小于第一预设电压VL时，每次电源转换电路302根据第一电流I1，由电压输出端Vout输出的供电电压VLED增加的电压变化量△V均相等，从而可以均匀的增加供电电压VLED。在此情况下，可以每次均匀抬升灯串组21第二端a的电压(即供电电压VLED)。灯串组21第一端c的电压，即驱动电路301的通道端口CH的电压也会每次均匀上升，并位于VL～VH的范围内。
基于此，为了根据需要对电压变化量△V的大小进行设定，在本申请的一些实施例中，上述电源转换电路302可以包括如图8所示的第一电阻R1。为了方便说明，第一电阻的阻值也采用R1表示。此外，在电源转换电路302中，为了使得电源转换电路302的电压输出端Vout能够正常输出供电电压VLED，该电源转换电路302还设置有与第一电阻R1串联的第三电阻R3。
该第三电阻R3远离第一电阻R1的第一端与接地端GND耦接。通过第一电阻R1和第三电阻R3对电压输出端Vout的电压进行分压，以得到节点FB的电压。该节点FB的电压可以进入到电源转换电路302的误差判断器(图中未示出)中，以与该电源 转换电路302内部的参考电压进行比对，从而使得电压输出端Vout输出正常的供电电压VLED。
基于此，该第一电阻R1的第一端与电源转换电路302的电压输出端Vout相耦接，第一电阻R1的第二端与驱动电路301的反馈信号端FBO相耦接。在此情况下，上述电压变化量△V＝|△I|×R1。
需要说明的是，本申请对第一电阻R1的阻值大小不做限定，可以根据每次对供电电压VLED进行微调的电压变化量△V和第一电流I1的大小进行设定。例如，在本申请的一些实施例中，上述第一电流源321产生的第一电流I1可以为几百mA。每次对供电电压VLED进行微调的电压变化量△V可以设置为几百mV，例如300mV。此时，上述第一电阻R1的阻值可以小于300KΩ。
在此基础上，在本申请的一些实施例中，如图8所示，上述背光控制电路30还可以包括第二电阻R2。该第二电阻R2的第一端与第一电阻R1的第二端相耦接，第二电阻R2的第二端与驱动电路301的反馈信号端FBO相耦接。该第二电阻用于对第一电阻R1的第二端和驱动电路301反馈信号端FBO进行阻抗匹配。
S203、当所有通道端口CH的电压Vch均大于第二预设电压VH时，由驱动电路301的反馈信号端FBO提供第二电流I2作为电流反馈信号。
驱动电路301为了能够执行上述S203，该驱动电路301如图7所示，可以包括第二电流源322，该第二电流源322用于执行上述S203。
示例的，如图7所示，第二电流源322的控制端(Con)与比较器311的第二输出端O2相耦接。第二电流源322的第一极(例如正极“+”)耦接第二电压端VCC。第二电压端VCC用于输出第二电压V2。此外，第二电流源322的第二极(例如负极“-”)耦接驱动电路301的反馈信号端FBO。
例如，在本申请的一些实施例中，该第二电压端VCC输出的第二电压V2可以为高电平。在此情况下，第一电压端，例如接地端GND输出的第一电压V1的电压值小于该第二电压端VCC输出的第二电压V2，即|V1|＜|V2|。
在此情况下，当比较器311的比较结果为所有通道端口CH的电压Vch均大于第二预设电压VH时，该比较器311的第二输出端O2输出有效信号，可以称为第二控制信号，且当第二电流源322的控制端(Con)接收到上述第二控制信号时开始工作，产生第二电流I2，并作为驱动电路301的反馈信号端FBO提供的电流反馈信号。
由于第二电流源322的正极“+”耦接第二电压端VCC，负极“-”耦接动电路301的反馈信号端FBO，因此该第二电流源322产生的第二电流I2可以为流向电源转换电路302的拉电流(source)。基于此，第一电流I1和第二电流I2的方向相反。
接下来，电源转换电路302根据上述电流反馈信号，减小电压输出端Vout的供电电压VLED。
由上述可知，当所有通道端口CH的电压Vch均大于第二预设电压VH时，由驱动电路301的反馈信号端FBO提供第二电流I2作为电流反馈信号。在上述多个灯串组21、电源转换电路302以及驱动电路301构成的回路中，由于第二电流I2为流向电源转换电路302的拉电流，因此根据电流由高电势流向低电势的特性，电源转换电路302的电压输出端Vout，输出的供电电压VLED会在原有电压大小的基础上减小。
基于此，同理可得，当所有通道端口CH的电压Vch连续N次(如一次对应2帧，N次为N×2帧，其中，N≥2；N为正整数)均大于第二预设电压VH时，驱动电路301的反馈信号端FBO提供的第二电流I2会以步进的方式每次减小电流变化量△I。在上述多个灯串组21、电源转换电路302以及驱动电路301构成的回路中，由于第二电流I2为流向电源转换电路302的拉电流，因此根据电流由高电势流向低电势的特性，电源转换电路302每次根据第二电流I2，将电压输出端Vout的电压，即供电电压VLED减小电压变化量△V。
这样一来，当所有通道端口CH的电压Vch连续N次均大于第二预设电压VH时，每次电源转换电路302根据第二电流I2，由电压输出端Vout输出的供电电压VLED，其减小的电压变化量△V均相等，从而可以均匀的减小供电电压VLED。在此情况下，可以每次均匀的减小灯串组21第二端a的电压(即供电电压VLED)。因此灯串组21第一端c的电压，即驱动电路301的通道端口CH的电压会每次均匀的减小，并位于VL～VH的范围内。
图8综上所述，驱动电路301中的比较器311可以每一帧对所有通道端口CH的电压Vch进行检测。驱动电路301可以每次根据比较器311的检测结果，可以提供第一电流I1(即灌电流)，以抬升电源转换电路302的电压输出端Vout输出的供电电压VLED。或者，驱动电路301的反馈信号端FBO可以每次根据比较器311的检测结果，又可以提供第二电流I2(即拉电流)，以减小电源转换电路302的电压输出端Vout输出的供电电压VLED。因此本申请实施例提供的背光控制电路30能够对灯串组21第二端a的电压进行双向调节。
基于上述方法，示例的，当背光控制电路30上电后，在如图9所示的第一阶段A，图8所示的电源转换电路302的电压输出端Vout可以通过驱动电路301的供电端口Vps向各个灯串组21的第二端a提供初始电压Vref。
当初始电压Vref较大时，驱动电路301中的比较器311可以经过一预设时间，例如1个帧(时长为P)，检测到所有通道端口CH的电压Vch均大于上述第二预设电压VH，并向第二电流源322的控制端con输出有效控制信号。
此时，第二电流源322生成第二电流I2(拉电流)作为反馈信号端FBO提供的电流反馈信号。电源转换电路302根据该第二电流I2，将电源转换电路302电压输出端Vout的电压减小，例如减小上述电压变化量△V，达到将电源转换电路302电压输出端Vout输出电压调整至正确的电压值的目的。
在此情况下，在第二帧之后，在如图9所示的第二阶段B，电源转换电路302电压输出端Vout能够向各个灯串组21的第二端a持续输出正确的供电电压VLED。
此外，当背光模组20中的多个灯串组21中由部分发光器件202损坏，导致该发光器件202所在的灯串200出现开路时，本申请实施例提供的背光控制电路的控制方法还包括对灯串200的开路进行检测的方法。
具体的，上述控制方法还包括：
S301、当驱动电路301的反馈信号端FBO提供的第一电流I1(即灌电流)以步进的方式连续S次增加电流变化量△I后，该驱动电路301中的比较器311仍然判断出任意一个通道端口CH的电压Vch小于第一预设电压VL时，驱动电路301的反馈信 号端FBO处于高阻态。此时，认为灯串组21存在开路状态，该灯串组21中至少一个灯串200发生了损坏。其中S≥2，S为正整数。
需要说明的是，反馈信号端FBO处于高阻态，是指反馈信号端FBO的电流被完全释放，使得反馈信号端FBO相对参考地具有很大的阻抗，例如可以为几百KΩ，即为上述高阻态。此时，反馈信号端FBO不会再对电源转换电路302产生影响。
由上述可知，驱动电路301用于执行上述S301的过程中，在如图9所示的第三阶段C，在驱动电路301中的比较器311持续每一帧对所有通道端口的电压Vch进行检测的情况下，当驱动电路301中的比较器311连续S次检测到任意一个通道端口的电压Vch小于第一预设电压VL时(例如反馈信号端FBO每两帧输出一次第一电流I1，S次为S×2帧，即比较器311连续S×2帧检测到任意一个通道端口的电压Vch小于第一预设压电VL)，驱动电路301的反馈信号端FBO提供第一电流I1(即灌电流)以步进的方式连续S次，例如8次增加电流变化量△I，驱动电路301的反馈信号端FBO第S次提供的第一电流I1的电流值为8×△I。电源转换电路302每次根据第一电流I1，将电压输出端Vout输出的电压增加电压变化量△V。电压输出端Vout第S次输出的供电电压VLED在原有电压值的基础上增加8×△V。
但是由于多个灯串组21中存在处于开路状态的灯串200，所以无论电源转换电路302的电压输出端Vout输出的供电电压VLED的电压值如何上调，处于开路的灯串200的第二端a所耦接的通道端口CH的电压Vch仍然小于第一预设压电VL。
所以，第三阶段C结束后，电源转换电路302的电压输出端Vout输出最终经过S次抬升后的电压值(VLED+S×△V)。当驱动电路301中的比较器311仍然判断出任意一个通道端口CH的电压Vch小于第一预设电压VL时，驱动电路301的反馈信号端FBO处于高阻态。驱动电路301可以向显示终端的控制系统输出开路信号，以提示多个灯串组21中存在处于开路状态的灯串200，达到开路检测的目的。
S302、电源转换电路302的电压输出端Vout的电压恢复至初始电压Vref。
当驱动电路301可以向显示终端的控制系统输出开路信号后，为了避免电源转换电路302的电压输出端Vout输出的供电电压VLED继续上调，而对其他正常的灯串200造成影响。该电源转换电路302的电压输出端Vout恢复至初始电压Vref。
在本申请的一些实施例中，第三阶段C结束后，可以直接进入如图9所示的第五阶段E，电源转换电路302的电压输出端Vout恢复至初始电压Vref。
或者，在本申请的另一些实施例中，当第三阶段C结束后，可以在第三阶段B和第五阶段E之间增加第四阶段D。在该第四阶段D，电源转换电路302的电压输出端Vout会保持输出经过S+1次抬升后的电压值(VLED+(S+1)×△V)。在此情况下，当第四阶段D结束后，如果驱动电路301中的比较器311仍然判断出任意一个通道端口CH的电压Vch小于第一预设电压VL时，驱动电路301的反馈信号端FBO处于高阻态。这样一来，通过增加第四阶段D，以增加对通道端口CH的电压Vch大小进行判断的次数，达到减小通道端口CH的电压Vch大小出现误判的几率。接下来，可以进入如图9所示的第五阶段E，电源转换电路302的电压输出端Vout恢复至初始电压Vref。
其中，本申请对第四阶段D的时长不做限制，例如，第四阶段D可以包括三帧， 或者，包括两帧。
在此之后，驱动电路301的反馈信号端FBO会持续处于高阻态，电源转换电路302的电压输出端Vout会持续输出初始电压Vref，从而使得各个灯串组21中的各个灯串200工作在初始电压Vref下。
此外，当显示终端01的控制系统接收到上述开路信号后，可以向用户显示报警信息。用户可以根据当前显示终端01的显示效果自行判断是否需要对开路的灯串200进行维修。
需要说明的是，本申请对上述初始电压Vref的数值不做限定。本领域技术人员可以根据灯串200的前向电压VF的大小进行初步的估算。例如，当一个发光器件202在额定电流为2mA时的前向电压VF＝3V，且每个灯串200具有串联的6个发光器件202时。该灯串200所在的灯串组21需要的工作电压的初始值，即上述初始电压Vref可以大约在18V(6×3V)左右。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何在本申请揭露的技术范围内的变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (22)

  1. 一种背光控制电路，其特征在于，用于驱动至少一个灯串组；所述灯串组包括多个并联的灯串；所述背光控制电路，包括：
    驱动电路，具有反馈信号端和至少一个通道端口；所述通道端口与所述灯串组的第一端耦接；所述驱动电路用于获取各个所述通道端口的电压Vch，并基于所述电压Vch由所述反馈信号端提供电流反馈信号；
    电源转换电路，与所述反馈信号端耦接，且具有电压输出端；所述电压输出端用于向每个所述灯串组的第二端提供供电电压；所述电源转换电路用于对输入电压进行电压转换，并根据所述电流反馈信号，增大或减小所述供电电压。
  2. 根据权利要求1所述的背光控制电路，其特征在于，
    所述驱动电路具体用于：
    将各个所述通道端口的电压Vch与第一预设电压VL和第二预设电压VH进行比对；其中，VL＜VH；
    当任意一个所述通道端口的电压Vch小于第一预设电压VL时，由所述反馈信号端提供第一电流I1作为所述电流反馈信号，用于增大所述供电电压；
    当所有通道端口的电压Vch均大于第二预设电压VH时，由所述反馈信号端提供第二电流I2作为所述电流反馈信号，用于减小所述供电电压；
    其中，第一电流I1和第二电流I2方向相反。
  3. 根据权利要求2所述的背光控制电路，其特征在于，所述驱动电路包括比较器、第一电流源以及第二电流源；所述比较器的输入端与所述通道端口相耦接；所述比较器的第一输出端与所述第一电流源的控制端相耦接；所述比较器的第二输出端与所述第二电流源的控制端相耦接；所述比较器用于将各个所述通道端口的电压Vch与第一预设电压VL和第二预设电压VH进行比对，且当任意一个所述通道端口的电压Vch小于第一预设电压VL时，所述第一输出端输出第一控制信号，当所有通道端口的电压Vch均大于第二预设电压VH时，所述第二输出端输出第二控制信号；其中，VL＜VH；
    所述第一电流源的第一极耦接所述反馈信号端，第二极耦接第一电压端；所述第一电流源用于接收所述第一控制信号，所述反馈信号端提供所述第一电流I1；
    所述第二电流源的第一极耦接第二电压端，第二极耦接所述反馈信号端；所述第二电流源接收所述第二控制信号，所述反馈信号端提供所述第二电流I2；
    其中，所述第一电压端用于输出第一电压V1，所述第二电压端用于输出第二电压V2，|V1|＜|V2|。
  4. 根据权利要求1-3任一项所述的背光控制电路，其特征在于，所述电源转换电路包括第一电阻，具有阻值R1；所述第一电阻的第一端与所述电压输出端相耦接，所述第一电阻的第二端与所述反馈信号端相耦接。
  5. 根据权利要求4所述的背光控制电路，其特征在于，所述背光控制电路还包括第二电阻；
    所述第二电阻的第一端与所述第一电阻的第二端相耦接，所述第二电阻的第二端与所述驱动电路的反馈信号端相耦接；所述第二电阻用于对所述第一电阻的第二端和 所述反馈信号端进行阻抗匹配。
  6. 根据权利要求4所述的背光控制电路，其特征在于，
    所述驱动电路还具体用于：在任意一个所述通道端口的电压Vch连续S次小于第一预设电压VL过程中，由所述反馈信号端提供的第一电流I1以步进的方式连续S次增加电流变化量△I；其中，S≥2；S为正整数；
    所述电源转换电路还具体用于：每次根据所述第一电流I1，将所述电压输出端的电压增加电压变化量△V；所述电压变化量△V1＝|△I|×R1。
  7. 根据权利要求6所述的背光控制电路，其特征在于，
    所述驱动电路还具体用于：当所述反馈信号端提供的第一电流I1以步进的方式连续S次增加所述电流变化量△I后，判断出任意一个所述通道端口的电压Vch小于第一预设电压VL时，所述反馈信号端处于高阻态。
  8. 根据权利要求4所述的背光控制电路，其特征在于，
    所述驱动电路还具体用于：在所有通道端口的电压Vch连续N次均大于第二预设电压VH过程中，由所述反馈信号端提供的第二电流I2以步进的方式连续N次减小电流变化量△I；其中，N≥2；N为正整数；
    所述电源转换电路还具体用于：每次根据所述第二电流I1，将所述电压输出端的电压减小电压变化量△V；所述电压变化量△V1＝|△I|×R1。
  9. 根据权利要求1所述的背光控制电路，其特征在于，所述驱动电路还具有多个选通端口和与每个所述选通端口耦接的一个供电端口，所述供电端口还与所述电源转换电路的电压输出端相耦接；
    多个所述灯串组阵列排布；同一行的多个所述灯串组的第二端与一个所述选通端口相耦接；同一列的所述灯串组的第一端与所述驱动电路的一个所述通道端口相耦接。
  10. 根据权利要求1所述的背光控制电路，其特征在于，所述电源转换电路的电压输出端与每个所述灯串组的第一端相耦接。
  11. 一种背光控制电路的控制方法，其特征在于，所述背光控制电路用于驱动至少一个灯串组；所述灯串组包括多个并联的灯串；所述背光控制电路包括驱动电路和电源转换电路；驱动电路具有反馈信号端和至少一个通道端口；所述通道端口与所述灯串组的第一端耦接；所述电源转换电路与所述反馈信号端耦接，且具有电压输出端；
    所述方法包括：
    所述驱动电路获取所述通道端口的电压Vch，并基于所述电压Vch由所述反馈信号端提供电流反馈信号；
    所述电源转换电路根据所述电流反馈信号，增大或减小所述电压输出端的供电电压。
  12. 根据权利要求11所述的背光控制电路的控制方法，其特征在于，所述驱动电路获取所述通道端口的电压Vch，并提供电流反馈信号具体包括：
    所述驱动电路将各个所述通道端口的电压Vch与第一预设电压VL和第二预设电压VH进行比对；其中，VL＜VH；
    当任意一个所述通道端口的电压Vch小于第一预设电压VL时，所述驱动电路的反馈信号端提供第一电流I1作为所述电流反馈信号，用于增大所述供电电压；
    当所有通道端口的电压Vch均大于第二预设电压时，所述驱动电路的反馈信号端提供第二电流I2作为所述电流反馈信号，用于减小所述供电电压；
    其中，第一电流I1和第二电流I2方向相反。
  13. 根据权利要求12所述的背光控制电路的控制方法，其特征在于，所述驱动电路包括比较器、第一电流源以及第二电流源；所述比较器的输入端与所述通道端口相连接；所述比较器的第一输出端与所述第一电流源的控制端相耦接；所述第一电流源的第一极耦接所述反馈信号端，第二极耦接第一电压端；所述比较器的第二输出端与所述第二电流源的控制端相耦接；所述第二电流源的第一极耦接第二电压端，第二极耦接所述反馈信号端；其中，所述第一电压端用于输出第一电压V1，所述第二电压端用于输出第二电压V2，|V1|＜|V2|；
    所述驱动电路获取所述通道端口的电压Vch，并提供电流反馈信号具体包括：
    所述比较器将各个所述通道端口的电压Vch与第一预设电压VL和第二预设电压VH进行比对；其中，VL＜VH；
    当任意一个所述通道端口的电压Vch小于第一预设电压VL时，所述第一输出端输出第一控制信号；所述第一电流源接收所述第一控制信号，所述反馈信号端提供所述第一电流I1；
    当所有通道端口的电压Vch均大于第二预设电压VH时，所述第二输出端输出第二控制信号所述第二电流源接收所述第二控制信号，所述反馈信号端提供所述第二电流I2。
  14. 根据权利要求12或13所述的背光控制电路的控制方法，其特征在于，所述电源转换电路包括第一电阻，具有阻值R1；所述第一电阻的第一端与所述电压输出端相耦接，所述第一电阻的第二端与所述反馈信号端相耦接；
    所述驱动电路获取所述通道端口的电压Vch，并基于所述电压Vch由所述反馈信号端提供电流反馈信号包括：在任意一个所述通道端口的电压Vch连续S次小于第一预设电压VL过程中，由所述反馈信号端提供的第一电流I1以步进的方式连续S次增加电流变化量△I；其中，S≥2，S为正整数；
    所述电源转换电路根据所述电流反馈信号，增大或减小所述电压输出端的供电电压包括：所述电源转换电路每次根据所述第一电流I1，将所述电压输出端的电压增加电压变化量△V；所述电压变化量△V1＝|△I|×R1。
  15. 根据权利要求14所述的背光控制电路的控制方法，其特征在于，所述方法还包括：
    当所述驱动电路的反馈信号端提供的第一电流I1以步进的方式连续S次增加所述电流变化量△I后，判断出任意一个所述通道端口的电压Vch小于第一预设电压V时，所述驱动电路的反馈信号端处于高阻态；
    所述电源转换电路的电压输出端的电压恢复至初始电压。
  16. 根据权利要求12或13所述的背光控制电路的控制方法，其特征在于，所述电源转换电路包括第一电阻，具有阻值R1；所述第一电阻的第一端与所述电压输出端相耦接，所述第一电阻的第二端与所述反馈信号端相耦接；
    所述驱动电路获取所述通道端口的电压Vch，并基于所述电压Vch由所述反馈信 号端提供电流反馈信号包括：当所有通道端口的电压Vch连续N次均大于第二预设电压VH时，由所述反馈信号端提供的第二电流I2以步进的方式连续N次减小电流变化量△I；其中，N≥2；N为正整数；
    所述电源转换电路根据所述电流反馈信号，增大或减小所述电压输出端的供电电压包括：所述电源转换电路每次根据所述第二电流I1，将所述电压输出端的电压减小电压变化量△V；所述电压变化量△V1＝|△I|×R1。
  17. 一种显示终端，其特征在于，包括液晶显示面板，用于向所述液晶显示面板提供光源的背光模组；所述背光模组包括多个灯串组和背光控制电路；所述灯串组包括多个并联的灯串；每个所述灯串包括多个串联的发光器件；
    所述背光控制电路包括：
    驱动电路，具有反馈信号端和至少一个通道端口；所述通道端口与所述灯串组的第一端耦接；所述驱动电路用于获取各个所述通道端口的电压Vch，并基于所述电压Vch由所述反馈信号端提供电流反馈信号；
    电源转换电路，与所述反馈信号端耦接，且具有电压输出端；所述电压输出端用于向每个所述灯串组的第二端提供供电电压；所述电源转换电路用于根据所述电流反馈信号，增大或减小所述电压输出端的供电电压。
  18. 根据权利要求17所述的显示终端，其特征在于，所述液晶显示面板包括多个阵列排布的亚像素；多个所述灯串组阵列排布；
    M×N个亚像素所在的区域在所述背光模组的垂直投影，与一个所述灯串组所在的区域重叠；其中，M≥1，N≥1，N、M为正整数。
  19. 根据权利要求18所述的显示终端，其特征在于，所述驱动电路还具有多个选通端口和与每个所述选通端口耦接的供电端口，所述供电端口还与所述电源转换电路的电压输出端相耦接；所述背光模组还包括多个第二信号线和第一信号线；
    一条所述第二信号线分别与同一行的多个所述灯串组的第二端，以及一个所述选通端口相耦接；
    一条所述第一信号线分别与同一列的所述灯串组的第一端，以及所述驱动电路的一个所述通道端口相耦接。
  20. 一种驱动电路，其特征在于，所述驱动电路具有反馈信号端和至少一个通道端口；所述通道端口与灯串组的第一端耦接；所述驱动电路用于获取各个所述通道端口的电压Vch，并基于所述电压Vch由所述反馈信号端提供电流反馈信号给电源转换电路，以使得所述电源转换电路根据所述电流反馈信号，增大或减小给所述灯串组的第二端的输出电压。
  21. 根据权利要求20所述的驱动电路，其特征在于，
    所述驱动电路具体用于：
    将各个所述通道端口的电压Vch与第一预设电压VL和第二预设电压VH进行比对；其中，VL＜VH；
    当任意一个所述通道端口的电压Vch小于第一预设电压VL时，由所述反馈信号端提供第一电流I1作为所述电流反馈信号，用于增大供电电压；
    当所有通道端口的电压Vch均大于第二预设电压VH时，由所述反馈信号端提供 第二电流I2作为所述电流反馈信号，用于减小所述供电电压；
    其中，第一电流I1和第二电流I2方向相反。
  22. 根据权利要求21所述的驱动电路，其特征在于，所述驱动电路包括比较器、第一电流源以及第二电流源；所述比较器的输入端与所述通道端口相耦接；所述比较器的第一输出端与所述第一电流源的控制端相耦接；所述比较器的第二输出端与所述第二电流源的控制端相耦接；所述比较器用于将各个所述通道端口的电压Vch与第一预设电压VL和第二预设电压VH进行比对，且当任意一个所述通道端口的电压Vch小于第一预设电压VL时，所述第一输出端输出第一控制信号，当所有通道端口的电压Vch均大于第二预设电压VH时，所述第二输出端输出第二控制信号；其中，VL＜VH；
    所述第一电流源的第一极耦接所述反馈信号端，第二极耦接第一电压端；所述第一电流源用于接收所述第一控制信号，所述反馈信号端提供所述第一电流I1；
    所述第二电流源的第一极耦接第二电压端，第二极耦接所述反馈信号端；所述第二电流源接收所述第二控制信号，所述反馈信号端提供所述第二电流I2；
    其中，所述第一电压端用于输出第一电压V1，所述第二电压端用于输出第二电压V2，|V1|＜|V2|。
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