WO2023165424A1 - 背光驱动电路、芯片、背光模组及电子设备 - Google Patents

背光驱动电路、芯片、背光模组及电子设备 Download PDF

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Publication number
WO2023165424A1
WO2023165424A1 PCT/CN2023/078144 CN2023078144W WO2023165424A1 WO 2023165424 A1 WO2023165424 A1 WO 2023165424A1 CN 2023078144 W CN2023078144 W CN 2023078144W WO 2023165424 A1 WO2023165424 A1 WO 2023165424A1
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Prior art keywords
terminal
transistor
control
current source
coupled
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PCT/CN2023/078144
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English (en)
French (fr)
Inventor
李涛
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华为技术有限公司
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Publication of WO2023165424A1 publication Critical patent/WO2023165424A1/zh

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Classifications

    • 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
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G—PHYSICS
    • 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
    • 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
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/34—Voltage stabilisation; Maintaining constant voltage

Definitions

  • the embodiments of the present application relate to the field of display technology, and in particular to a backlight driving circuit, a chip, a backlight module and electronic equipment.
  • backlight modules are used to provide backlight for liquid crystal panels.
  • mainstream backlight solutions include global dimming and local dimming (or local dimming/dimming) technologies.
  • mini light-emitting diodes mini LEDs
  • mini LEDs are widely used in backlight panels as light-emitting units of light strings for backlighting.
  • the switch and brightness adjustment of the corresponding backlight area can be controlled in real time, so that the black in the picture is darker, the white is whiter, and the color is more natural and gorgeous, with a sense of visual realism Bring the best immersive experience.
  • the mini LED backlight solution usually uses more channels CH (channel, usually each channel corresponds to a backlight string (including multiple LEDs in series), and the backlight drive circuit provides current to each channel to drive the corresponding backlight string to emit light ) to drive many LEDs, the power level is relatively large.
  • the power level of the backlight is getting higher and higher.
  • the power consumption of the backlight of a TV product reaches several hundred watts, and the power loss cannot be ignored when the power conversion efficiency is counted.
  • the relationship between the forward voltage (voltage forward, VF) and the current of the LED is that the higher the voltage, the larger the conduction current.
  • LEDs Under the same conduction current, LEDs have different VFs due to manufacturing process and material reasons. In this way, due to the difference in the manufacturing process of the LED, the VF of the LED is finally different.
  • the voltage of each channel usually the voltage V CHx of the channel is the anode voltage Vout of the backlight string and the voltage drop V LS of the string The sum of VF) and the difference) are also not the same.
  • the VF of each LED is different between channels, under the same current I LED flowing through, the total forward voltage (V LS ) of the backlight strings connected to each channel is different, resulting in the voltage V CHx of each channel Also vary. In this way, when the voltage V CHx of a certain channel is high, the loss of the backlight driving circuit will be increased.
  • the current source usually including a metal-oxide half-field-effect transistor (metal-oxide field-effect transistor) -semiconductor field-effect transistor, MOSFET
  • MOSFET metal-oxide half-field-effect transistor
  • Embodiments of the present application provide a backlight driving circuit, a chip, a backlight module and electronic equipment, which can reduce the loss of the backlight driving circuit.
  • a backlight driving circuit is provided.
  • the backlight drive circuit is applied to a backlight module, and at least one backlight string is arranged on the lamp board of the backlight module, and the backlight string includes at least one light-emitting unit connected in series; the backlight drive
  • the circuit includes: a control circuit, at least one driving circuit and at least one current source.
  • the first terminal of the current source is used for coupling to the cathode of the backlight string, and the anode of the backlight string is used for coupling to the power supply; the second terminal of the current source is used for coupling to the ground; the driving circuit is coupled to the control terminal of the current source; the control The circuit is coupled to the drive circuit, and the control circuit is also coupled to the first terminal of the current source or the control terminal of the current source; the control circuit is configured to detect the electrical signal of the first terminal of the current source or the control terminal of the current source; the control circuit is further configured to output a control signal to the drive circuit according to the electrical signal; the drive circuit is configured to adjust the current flowing through the first terminal and the second terminal of the current source and the voltage of the first terminal of the current source according to the control signal.
  • the current source can be adjusted dynamically by detecting the electrical signal at the first terminal of the current source or the control terminal of the current source, and the current flowing through the first terminal and the second terminal of the current source, as well as the voltage at the first terminal of the current source, to avoid The current source generates excessive losses when supplying current to its corresponding backlight string.
  • the drive circuit includes an operational amplifier and a first switch;
  • the current source includes a drive transistor and a first resistor;
  • the first end of the drive transistor is coupled to the first end of the current source, and the second end of the drive transistor terminal is coupled to the second terminal of the current source through the first resistance,
  • the control terminal of the drive transistor is coupled to the control terminal of the current source;
  • the positive input terminal of the operational amplifier is coupled to the control circuit, and the inverting input terminal of the operational amplifier is coupled to the drive The second terminal of the transistor;
  • the output terminal of the operational amplifier is coupled to the first terminal of the first switch, and the second terminal of the first switch is coupled to the control terminal of the driving transistor;
  • the control signal includes a voltage signal and a switch control signal;
  • the positive terminal of the operational amplifier The input terminal is configured to receive a voltage signal, and the control terminal of the first switch is configured to receive a switch control signal; wherein, when the switch control signal turns on the first switch, the voltage signal is used to control the first switch flowing
  • control circuit determines that the voltage corresponding to the electrical signal is greater than the first threshold, the control circuit controls the drive circuit through the control signal to increase the current flowing through the first terminal and the second terminal of the current source, and The voltage at the first terminal of the current source is decreased.
  • the control circuit determines that the corresponding voltage is greater than the threshold according to the electrical signal of the first terminal of a certain current source or the control terminal of the current source, it indicates that the voltage of the first terminal of the current source is too high, that is, the current source is in the direction of
  • the corresponding backlight string provides current, excessive loss occurs, and if the voltage at the first end of the current source is directly reduced by reducing the current, it may not be possible to ensure that the backlight string connected to the current source is normally illuminated.
  • the control circuit determines that the electrical signal is greater than the first threshold, and the control circuit controls the driving circuit through the control signal to increase the current flowing through the first end and the second end of the current source, and reduce the current of the current source.
  • the voltage of the first terminal thus while ensuring the normal light emission of the backlight string, since the voltage of the first terminal of the current source is reduced, the loss generated on the current source is also reduced, thereby reducing the overall loss of the backlight drive circuit .
  • the control circuit determines that the voltage corresponding to the electrical signal is less than the second threshold, and the control circuit controls the driving circuit to reduce the current flowing through the first terminal and the second terminal of the current source through the control signal, and increase the voltage at the first terminal of the current source.
  • the embodiments of the present application also provide an application scenario where there is a need to increase the voltage of the first terminal of the current source while reducing the current flowing through the first terminal and the second terminal of the current source.
  • control circuit adjusts (decreases or increases) the voltage at the first terminal of the current source, it can be adjusted according to a certain step size, and different step sizes can be set according to different application scenarios, for example, for mobile phones with low power consumption, you can set a smaller step size; for large-screen devices with high power consumption, you can set a larger step size; in order to ensure the adjustment accuracy as much as possible and shorten the time for adjusting the voltage.
  • the bandgap reference source is connected to the driving circuit between the circuit and the control circuit; the bandgap reference source is configured to adjust the voltage signal according to a predetermined ratio.
  • the first switch includes: a first transistor and a second transistor; the first end of the first transistor is coupled to the ground, the second end of the first transistor is coupled to the control end of the second transistor, and the first end of the first transistor is coupled to the ground.
  • the control terminal of a transistor is coupled to the control circuit; the first terminal of the second transistor is coupled to the output terminal of the operational amplifier, the second terminal of the second transistor is coupled to the control terminal of the drive transistor, and the control terminal of the second transistor is also passed through the second
  • the resistor is coupled to the output terminal of the operational amplifier; the first transistor is configured to periodically conduct the first terminal of the first transistor and the second terminal of the first transistor under the control of the switch control signal; the second transistor is controlled by configured to conduct the first terminal of the second transistor with the second terminal of the second transistor when the first terminal of the first transistor is conducted with the second terminal of the first transistor, so as to transmit the signal at the output terminal of the operational amplifier to the control terminal of the drive transistor.
  • the first transistor includes an N-type transistor
  • the second transistor includes a P-type transistor
  • the first end of the first transistor is the source of the N-type transistor
  • the second end of the first transistor is an N-type transistor.
  • the drain of the transistor, the control end of the first transistor is the gate of the N-type transistor
  • the first end of the second transistor is the source of the P-type transistor
  • the second end of the second transistor is the drain of the P-type transistor
  • the control terminal of the second transistor is the gate of the P-type transistor.
  • the N-type transistor when the N-type transistor is turned on, the current flows from the drain (d) pole to the source (source, s) pole, and when the P-type transistor is turned on, the current flows from the s pole to the d pole, and the s pole of the N-type transistor
  • the pole is connected to the ground GND as a fixed voltage, which is convenient for circuit design, and when the N-type transistor is turned on, the second resistor provides a fixed voltage difference between the s-pole and the g-pole of the P-type transistor, as long as the voltage of the s-pole is greater than the g-pole, and
  • the conduction of Q13 can be realized by satisfying the threshold condition of conduction.
  • it also includes: at least one comparator and a reference voltage generating circuit; the positive input terminal of the comparator is coupled to the first terminal of the current source or the control terminal of the current source, and the negative input terminal of the comparator A terminal coupling reference voltage generation circuit; an output terminal coupling control circuit of the comparator; a reference voltage generation circuit configured to generate a first reference voltage; a comparator configured to compare the voltage at the first end of the current source with the first reference voltage Comparing, or comparing the control terminal voltage of the current source with the first reference voltage, and outputting the comparison result at the output terminal of the comparator; the control circuit is configured to determine the control of the first terminal of the current source or the current source according to the comparison result terminal electrical signal. In this way, the control circuit can detect the signal of the first terminal or the control terminal of the current source in the digital domain.
  • a selector wherein the selector includes a plurality of input terminals, an output terminal and at least one control terminal, and the first terminal of the current source or the control terminal of the current source is coupled to the selector
  • the input terminal, the output terminal of the selector is coupled to the control circuit, at least one control terminal of the selector is coupled to the control circuit;
  • the control circuit is configured to output a gating control signal to the selector through at least one control terminal of the selector;
  • the selector configured to connect any input terminal of the selector with the output terminal of the selector according to the gate control signal.
  • each sub-light board of the backlight module needs to provide backlight strings with 16, 32, 48 or even more channels.
  • the solution provided by this possible implementation can be used In this way, the electrical signals of the first terminals of each current source are detected in time division, which reduces the complexity of the control circuit Miscellaneous.
  • a chip which is applied to a backlight module.
  • At least one backlight string is provided on the lamp board of the backlight module, and the backlight string includes at least one light-emitting unit connected in series;
  • the chip includes: at least one driving circuit and at least A current source; the first end of the current source is used to couple to the cathode of the backlight string, and the anode of the backlight string is coupled to the power supply; the second end of the current source is used to couple to the ground; the driving circuit is coupled to the current source
  • the control terminal of the drive circuit is also used to be coupled to the control circuit; the first terminal of the current source or the control terminal of the current source is also used to be coupled to the control circuit;
  • the control circuit is configured to detect the first terminal of the current source or the current An electrical signal at the control terminal of the source;
  • the control circuit is further configured to output a control signal to the drive circuit according to the electrical signal;
  • the drive circuit is configured to adjust the current flowing through the first terminal and the second terminal
  • the drive circuit includes an operational amplifier and a first switch;
  • the current source includes a drive transistor and a first resistor; the first end of the drive transistor is coupled to the first end of the current source, and the second end of the drive transistor passes through
  • the first resistor is coupled to the second terminal of the current source, the control terminal of the driving transistor is coupled to the control terminal of the current source; the positive input terminal of the operational amplifier is coupled to the control circuit, and the negative input terminal of the operational amplifier is coupled to the second terminal of the driving transistor.
  • the output terminal of the operational amplifier is coupled to the first terminal of the first switch, and the second terminal of the first switch is coupled to the control terminal of the drive transistor;
  • the control signal includes a voltage signal and a switch control signal;
  • the positive input terminal of the operational amplifier is Configured to receive a voltage signal, the control terminal of the first switch is configured to receive a switch control signal; wherein, when the switch control signal turns on the first switch, the voltage signal is used to control the flow through the first terminal of the driving transistor and the second The current at the end, the switch control signal is used to control the voltage at the first end of the driving transistor.
  • control circuit determines that the voltage corresponding to the electrical signal is greater than the first threshold, the control circuit controls the drive circuit through the control signal to increase the current flowing through the first terminal and the second terminal of the current source, and The voltage at the first terminal of the current source is decreased.
  • control circuit determines that the voltage corresponding to the electrical signal is greater than the second threshold, the control circuit controls the drive circuit to reduce the current flowing through the first end and the second end of the current source through the control signal, and increase the voltage at the first terminal of the current source.
  • it also includes: a bandgap reference source connected between the positive input terminal of the operational amplifier and the control circuit; the bandgap reference source is configured to Adjust the voltage signal.
  • the first switch includes: a first transistor and a second transistor; the first end of the first transistor is coupled to the ground, the second end of the first transistor is coupled to the control end of the second transistor, and the first end of the first transistor is coupled to the ground.
  • the control terminal of a transistor is coupled to the control circuit; the first terminal of the second transistor is coupled to the output terminal of the operational amplifier, the second terminal of the second transistor is coupled to the control terminal of the drive transistor, and the control terminal of the second transistor is also passed through the second
  • the resistor is coupled to the output terminal of the operational amplifier; the first transistor is configured to periodically conduct the first terminal of the first transistor and the second terminal of the first transistor under the control of the switch control signal; the second transistor is controlled by configured to conduct the first terminal of the second transistor with the second terminal of the second transistor when the first terminal of the first transistor is conducted with the second terminal of the first transistor, so as to transmit the signal at the output terminal of the operational amplifier to the control terminal of the drive transistor.
  • the first transistor includes an N-type transistor
  • the second transistor includes a P-type transistor
  • the first end of the first transistor is the source of the N-type transistor
  • the second end of the first transistor is an N-type transistor.
  • the drain of the transistor, the control terminal of the first transistor is the gate of the N-type transistor;
  • the first terminal of the second transistor is the source of the P-type transistor;
  • the second terminal of the second transistor is the drain of the P-type transistor, and the second terminal of the second transistor is the drain of the P-type transistor.
  • the control terminal of the second transistor is a P-type crystal
  • the gate of the body tube is a P-type crystal
  • it also includes: at least one comparator and a reference voltage generating circuit; the positive input terminal of the comparator is coupled to the first terminal of the current source or the control terminal of the current source, and the negative input terminal of the comparator A terminal coupling reference voltage generation circuit; an output terminal coupling control circuit of the comparator; a reference voltage generation circuit configured to generate a first reference voltage; a comparator configured to compare the voltage at the first end of the current source with the first reference voltage Comparing, or comparing the control terminal voltage of the current source with the first reference voltage, and outputting the comparison result at the output terminal of the comparator; the control circuit is configured to determine the first terminal of the current source or the current source according to the comparison result The electrical signal of the control terminal.
  • a selector wherein the selector includes a plurality of input terminals, an output terminal and at least one control terminal, and the first terminal of the current source or the control terminal of the current source is coupled to the selector
  • the input terminal, the output terminal of the selector is coupled to the control circuit, at least one control terminal of the selector is coupled to the control circuit;
  • the control circuit is configured to output a gating control signal to the selector through at least one control terminal of the selector; the selector , configured to connect any input terminal of the selector with the output terminal of the selector according to the gate control signal.
  • control circuit is included in the chip.
  • a backlight module in a third aspect, includes a backplane, a flat board, a lamp board, and a diffusion board; wherein, the flat board is located between the back board and the lamp board, and the lamp board is located between the flat board and the diffusion board. Between; at least one backlight string is arranged on the lamp board, and the above-mentioned backlight driving circuit or the above-mentioned chip is arranged on the backboard.
  • an electronic device including the above-mentioned backlight module, and a liquid crystal panel disposed on the backlight module.
  • FIG. 1 is a schematic diagram of the overall structure of an electronic device provided by an embodiment of the present application.
  • Fig. 2 is a schematic diagram of an exploded structure of a screen assembly provided by an embodiment of the present application
  • Fig. 3 is a schematic structural diagram of a seed lamp panel provided by an embodiment of the present application.
  • Fig. 4 is a schematic structural diagram of a seed lamp panel provided by another embodiment of the present application.
  • FIG. 5 is a schematic structural diagram of a connector provided in an embodiment of the present application.
  • FIG. 6 is a schematic diagram of a connection structure between a control module and a connector provided by an embodiment of the present application.
  • FIG. 7 is a schematic diagram of a backlight driving circuit provided by an embodiment of the present application.
  • FIG. 8 is a schematic diagram of a backlight driving circuit provided by an embodiment of the present application.
  • FIG. 9 is a schematic diagram of a partial structure of a backlight driving circuit provided by an embodiment of the present application.
  • FIG. 10 is a schematic diagram of a current and voltage curve of an LED provided by an embodiment of the present application.
  • FIG. 11 is a schematic diagram of a backlight driving circuit provided by another embodiment of the present application.
  • FIG. 12 is a schematic diagram of a backlight driving circuit provided by another embodiment of the present application.
  • FIG. 13 is a partial structural schematic diagram of a backlight driving circuit provided by another embodiment of the present application.
  • FIG. 14 is a partial structural schematic diagram of a backlight driving circuit provided by another embodiment of the present application.
  • FIG. 15 is a schematic diagram of a backlight driving circuit provided by another embodiment of the present application.
  • FIG. 16 is a schematic diagram of a backlight driving circuit provided by another embodiment of the present application.
  • FIG. 17 is a partial structural schematic diagram of a backlight driving circuit provided by yet another embodiment of the present application.
  • FIG. 18 is a schematic diagram of a backlight driving circuit provided by another embodiment of the present application.
  • FIG. 19 is a schematic diagram of a backlight driving circuit provided by another embodiment of the present application.
  • FIG. 20 is a schematic diagram of a backlight driving circuit provided by another embodiment of the present application.
  • FIG. 21 is a schematic diagram of a backlight driving circuit provided by another embodiment of the present application.
  • FIG. 22 is a schematic diagram of a backlight driving circuit provided by another embodiment of the present application.
  • FIG. 23 is a schematic diagram of a chip provided by an embodiment of the present application.
  • FIG. 24 is a schematic diagram of a chip provided by another embodiment of the present application.
  • first and second are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as “first” and “second” may explicitly or implicitly include one or more of these features.
  • plural means two or more. Additionally, the use of “based on” is meant to be open and inclusive, as a process, step, calculation, or other action that is “based on” one or more stated conditions or values may in practice be based on additional conditions or beyond stated values.
  • the transistor provided in the embodiment of the present application may be a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET).
  • MOSFET Metal-Oxide-Semiconductor Field-Effect Transistor
  • transistors are classified into two types: N (negative, negative) type transistors and P (positive, positive) type transistors.
  • the transistor includes a source, a drain, and a gate. By controlling the level input to the gate of the transistor, the transistor can be controlled to be turned on (turned on) or turned off (turned off, cut off, or disconnected).
  • the source and drain When the transistor is turned on, the source and drain are turned on to generate a turn-on current, and when the gate levels of the transistor are different, The turn-on current generated between the source and drain is also different; when the transistor is turned off, the source and drain will not conduct and no current will be generated.
  • the gate of the transistor is also called the control terminal, the source is called the first terminal, and the drain is called the second terminal; or, the gate is called the control terminal, and the drain is called the second terminal. is called the first terminal, and the source is called the second terminal.
  • the N-type transistor is turned on when the level of the control terminal is high, the first terminal and the second terminal are turned on, and a turn-on current is generated between the first terminal and the second terminal; the level of the N-type transistor is low at the control terminal. Normally closed, the first terminal and the second terminal are not conducted, and no current is generated.
  • the P-type transistor is turned on when the level of the control terminal is low, and the first terminal and the second terminal are turned on to generate a turn-on current; the P-type transistor is turned off when the level of the control terminal is high, and the first terminal and the second terminal are not connected. conduction, no current flow.
  • FIG. 1 is a schematic structural diagram of an electronic device 100 provided by an embodiment of the present application.
  • the electronic device 100 may be an advertising screen (billboard), a display, a television (TV, such as a smart screen), a notebook computer, a tablet computer, a vehicle-mounted device, and other screen-type electronic devices.
  • the electronic device 100 may be a device such as a mobile phone, an e-reader, or a wearable device.
  • the embodiment shown in FIG. 1 is described by taking the electronic device 100 being a television as an example.
  • the electronic device 100 may include a case 110 and a screen assembly 200 .
  • the case 110 may include a bezel and a rear cover.
  • the frame can surround the periphery of the back cover.
  • the casing 110 may include, for example, a middle frame of the electronic device 100 .
  • the middle frame of the electronic device 100 can be accommodated in the inner periphery of the frame.
  • the middle frame of the electronic device 100 may serve as a frame of the casing 110 .
  • the screen assembly 200 may be an assembly providing a display function for the electronic device 100 . Users can watch the screen assembly 200 to enjoy media resources such as images and videos.
  • the screen assembly 200 may be installed on the case 110 .
  • the peripheral edge of the screen assembly 200 may abut against the inner edge of the frame.
  • the frame can fix the screen assembly 200 on the casing 110 .
  • the screen assembly 200 and the back cover can be installed on both sides of the frame respectively, so that the housing 110 can provide mechanical protection for the components inside the electronic device, especially the components on the screen assembly 200 .
  • the screen assembly 200 can be fixed on the middle frame of the electronic device 100, for example.
  • the electronic device 100 may also include a control module.
  • the specific implementation form of the control module may include, for example, a processor, a controller, a connector, a driver board, an integrated circuit, a chip, a power supply, and the like.
  • the control module may specifically include a backlight driving circuit, which may be in the form of a chip or integrated into a driving board, and may specifically include a power supply in the embodiment of the present application, and One or more of the control circuit, the driving circuit and the current source in the backlight driving circuit.
  • a control module can be disposed on the screen assembly 200 , and the control module can be accommodated in the casing 110 .
  • the control module may include at least one communication interface, a bus, at least one processor, and at least one memory. At least one communication interface, at least one processor and at least one memory can communicate with each other through the bus. At least one communication interface can be used to receive and transmit signals.
  • the light emitting unit of the screen assembly 200 can be connected to one of the communication interfaces, so that the control module can trigger the light emitting unit to emit light.
  • At least one memory is used to store application code.
  • the application program code may include, for example, code to control the lighting unit to emit light or not to emit light.
  • At least one processor can be used to execute the above application program codes to realize the control of the light emitting unit. In the present application, "at least one" includes, for example, one or more of the two cases.
  • FIG. 2 is an exploded view of the screen assembly 200 .
  • the screen assembly 200 shown in FIG. 2 includes a backlight module 210 and a liquid crystal panel 220 disposed on the light emitting side of the backlight module 210 .
  • the backlight module 210 may include a stacked back panel 211, a flat panel 212, a lamp panel 213, Diffusion plate 214, optical film 215 and other components.
  • the general structure of the backlight module 210 is merely provided in FIG. 2 as an example, and in some examples, the backlight module 210 may further include more or less components than those described above.
  • the backplane 211 may have functions such as supporting the electronic device 100 and providing mechanical protection for electronic components in the electronic device 100 .
  • the material of the back plate 211 may be a material that meets the requirements of mechanical strength and can play a supporting role.
  • the back plate 211 may be made of metal materials such as stainless steel, aluminum alloy, zinc alloy, titanium alloy and the like.
  • the back plate 211 may be made of non-metallic materials such as resin.
  • the back panel 211 may include a first back panel end surface and a second back panel end surface, the first back panel end surface is close to the lamp panel 213 , and the second back panel end surface is away from the lamp panel 213 .
  • the first backplane end surface may correspond to the front of the electronic device 100
  • the second backplane end surface may correspond to the back of the electronic device 100
  • the front of the electronic device 100 may be a side of the electronic device 100 that is often observed when the user uses the electronic device 100
  • the back of the electronic device 100 may be disposed opposite to the front of the electronic device 100
  • the back of the electronic device 100 may be a side of the electronic device 100 that is not often observed when the user uses the electronic device 100 .
  • the electronic device 100 may be a TV, and the side of the TV on which the screen assembly is installed may be the front of the TV; the side of the TV on which the rear cover is installed may be the back of the TV.
  • the first backplane end surface corresponds to the front of the electronic device 100 , which means that the first backplane end surface can be observed when the user observes the backplane 211 along the direction in which the user observes the front of the electronic device 100 .
  • the second backplane end surface corresponds to the back surface of the electronic device 100 , which means that the second backplane end surface can be observed when the user observes the backplane 211 along the direction in which the user observes the back surface of the electronic device 100 .
  • the first end surface of the backplane may be referred to as the front of the backplane 211
  • the second end surface of the backplane may be referred to as the backside of the backplane 211 .
  • the end surface of the first backplane may be fixed on the back cover of the housing 110 .
  • the end surface of the first backboard can be fixed on the rear cover of the housing 110 through mechanical connectors such as screws, double-sided tape, foam and the like.
  • the back plate 211 may serve as a rear cover of the housing 110 .
  • the flat board 212 may be located between the light board 213 and the back board 211 .
  • the flat plate 212 can be used to provide support for the lamp panel 213 to maintain or ensure the flatness of the lamp panel 213 .
  • the flat plate 212 may be a conductive material with a certain rigidity.
  • the flat plate 212 may be an aluminum plate.
  • the flat plate 212 can be fixed on the back plate 211 through mechanical connectors such as double-sided tape and foam, for example.
  • the electronic device 100 when the electronic device 100 is being transported, the electronic device 100 may be bumped, dropped or the like. In this case, the electronic device 100 can withstand a certain degree of external force.
  • the back plate 211 can be deformed accordingly to resist the external force.
  • the lamp board 213 may follow the back board 211 to undergo relatively obvious deformation. To avoid the occurrence of the above situation will increase the difficulty of transportation of the electronic device 100 .
  • the back panel 211 is relatively obviously deformed, it is not conducive to the display effect of the lamp panel 213 . For example, due to the different light mixing distances in different areas of the lamp panel 213 , display problems such as uneven brightness and darkness, ghost images, etc. may occur in the electronic device 100 .
  • the flat plate 212 is arranged between the back plate 211 and the lamp plate 213 , so that the flat plate 212 can play a transitional role between the light plate 213 and the back plate 211 in terms of deformation.
  • the deformation amount of the flat plate 212 may be smaller than that of the back plate 211, and thus the deformation amount of the lamp board 213 may tend to decrease. That is to say, in the case that the back plate 211 is relatively obviously deformed, the deformation amount of the lamp plate 213 can be relatively small or relatively inconspicuous as possible.
  • the optical film 215 can change the frequency of the light from the light panel 213 .
  • the optical film 215 may include quantum dots.
  • the lamp board 213 can emit high-energy blue light; the blue light can excite the quantum dots encapsulated in the optical film 215, so that the quantum dots can convert the blue light emitted by the lamp board 213 into white light (the quantum dot can be a nanoscale Semiconductor; by applying a certain electric field or light pressure to the quantum dots, the quantum dots can emit light of a specific frequency).
  • quantity The sub-dots can be formed by, for example, chemical coatings, phosphors.
  • the light emitted from the optical film 215 can enter the liquid crystal panel 220 , for example.
  • the liquid crystal panel 220 may include a liquid crystal layer and a filter layer.
  • the liquid crystal in the liquid crystal layer can control the liquid crystal unit to be turned on or off, so as to control the light intensity of the white light passing through the liquid crystal unit.
  • the filter layer may include a red light filter, a green light filter, and a blue light filter.
  • a red light filter can be used to convert white light to red light.
  • Green light filters can be used to convert white light to green light.
  • Blue light filters can be used to convert white light to blue light.
  • the electronic device 100 can be controlled to emit light of various colors to display color patterns.
  • the diffuser plate 214 may include quantum dots, so that the diffuser plate 214 may change the frequency of the light from the light panel 213 .
  • the diffusion plate 214 and the optical film 215 can be integrally formed.
  • the light emitted by the light board 213 may only undergo light mixing processing without other optical processing, and directly enter the diffuser plate 214 . That is to say, in some possible scenarios, quantum dots may not be arranged on the light emitting units of the light board 213 . This helps to reduce the structural complexity of the lamp board 213 , and facilitates that the light emitting units can be relatively closely arranged on the lamp board 213 .
  • the size of the phosphor powder is generally larger than the size of the light emitting units of the lamp board 213 , and packaging the phosphor powder on the lamp board 213 is not conducive to the compact arrangement of the light emitting units.
  • the light board 213 may also include a plurality of sub-light boards 2130 distributed in an array.
  • a sub-lamp board 2130 is taken as an example for description.
  • the sub-lamp board 2130 may include a first lamp board end surface 2131 and a second lamp board end surface 2132 .
  • Fig. 3 is a schematic structural diagram of a first lamp panel end surface 2131 of a seed lamp panel 2130 provided in an embodiment of the present application. The light emitted by the sub-lamp board 2130 can be emitted from the first lamp-board end surface 2131 of the sub-lamp board 2130 .
  • the first lamp panel end surface 2131 of the sub-lamp panel 2130 may be a surface of the sub-lamp panel 2130 that is close to the diffuser plate 214 and away from the back panel 211 .
  • the structure of the first lamp panel end surface 2131 of the sub-lamp panel 2130 will be described below with reference to FIG. 3 .
  • the sub lamp board 2130 may include a plurality of light emitting units 2133 .
  • the sub-light panel 2130 may include a plurality of light emitting units 2133 arranged in an array.
  • the light emitting unit 2133 may be, for example, a chip with a light emitting function.
  • the light emitting unit 2133 can also be a light emitting diode LED, wherein several light emitting units located in the same column or row can be connected to form a backlight string.
  • FIG. 4 is a schematic structural diagram of a second lamp panel end surface 2132 of a sub-lamp panel 2130 provided in an embodiment of the present application.
  • the second lamp panel end surface 2132 of the sub-lamp panel 2130 may be disposed close to the back panel 211 and away from the diffuser panel 214 .
  • the structure of the second lamp panel end surface 2132 of the sub-lamp panel 2130 will be described below with reference to FIG. 4 .
  • the second lamp board end surface 2132 of the sub-lamp board 2130 can be provided with double-sided adhesive tape, and the double-sided adhesive can be fixedly connected to the sub-lamp board 2130 and the flat board 212 .
  • the double-sided adhesive can be thermally conductive adhesive 2134 . Since the sub-lamp board 2130 may generate relatively high heat during operation, the thermally conductive adhesive 2134 is beneficial to transfer the heat of the sub-lamp board 2130 to the flat plate 212 , which is beneficial to improving the heat dissipation of the electronic device 100 .
  • the second lamp board end surface 2132 of the sub-lamp board 2130 may also be provided with a conductive elastic piece 2135 .
  • One end of the conductive elastic piece 2135 can be electrically connected to the sub-lamp board 2130 .
  • the other end of the conductive elastic piece 2135 can abut against the flat plate 212 .
  • the light emitting unit 2133 of the sub-lamp board 2130 may accumulate charges.
  • the sub-lamp board 2130 can be grounded through the conductive shrapnel 2135 , which is beneficial to improve the electromagnetic compatibility (electromagnetic compatibility, EMC) of the electronic device 100 .
  • EMC electromagnetic compatibility
  • the sub-light board 2130 may also include one or more backlight driving circuits 2136 and one or more connectors 2137 . Through the connector 2137, the signal related to the sub-light board 2130 can be input to the backlight driving circuit 2136 to control the backlight driving circuit 2136 to supply current to the light emitting unit 2133, thereby controlling the light and dark state of the light emitting unit 2133, so that the backlight driving circuit 2136 can be controlled according to The control signal controls the light and dark state of the light emitting unit 2133 . In, When the light emitting unit 2133 is in a bright state, the light emitting unit 2133 may be driven by the backlight driving circuit 2136 .
  • the brightness of the light emitting unit 2133 can be adjusted.
  • the light emitting unit 2133 may be turned off by the backlight driving circuit 2136 (ie, the light emitting unit 2133 may not be driven).
  • the connector 2137 may include a plurality of connector ports P (also referred to as pins, pins).
  • the connector 2137 may include 30 ⁇ 100 connector ports P.
  • the backlight driving circuit 2136 may include a plurality of signal input ports corresponding to a plurality of connector ports.
  • a plurality of connector ports and a plurality of signal input ports can be electrically connected through one-to-one, one-to-many, and many-to-many correspondences.
  • the connector port P can be used to transmit signals related to the sub-light board 2130 .
  • the backlight driving circuit 2136 when the backlight driving circuit 2136 is disposed in the above-mentioned control module, the current of the light emitting unit 2133 can also be directly transmitted to the sub-light board 2130 through the connector port P.
  • the backlight driving circuit 2136 can be used to drive a backlight string formed in series by one or more light-emitting units 2133 of the sub-light board 2130 , and control the light emission of each light-emitting unit 2133 of the sub-light board 2130 .
  • the backlight driving circuit 2136 can turn off one or more light emitting units 2133 connected in series in one backlight string, control the brightness of one or more light emitting units 2133 connected in series in one backlight string, and so on.
  • FIG. 6 only provides an example.
  • the control module 217 may include the power supply 31 and the backlight driving circuit 32 shown in FIG. 7 .
  • the power supply 31 can adopt a switching circuit, as shown in Figure 7, the input port Vin of the power supply 31 can be coupled to a battery or an external adapter to provide an input voltage to the switching circuit; the output port Vout of the power supply 31 can be coupled to each light string The anode of the anode, to provide the output voltage to each light string, here the switch circuit is specifically used to step down or boost the input voltage of the power supply 31 and then output the output voltage to the output port Vout; exemplary, the switch circuit specifically includes an inductor L1, diode D1, switching transistor M1 and resistor R CS , wherein the inductor L1 and the diode D1 are connected in series between the input port Vin and the output port Vout, wherein the anode of the diode D1 is electrically connected to the inductor L1, and the cathode of the diode D1 is connected to the output port V
  • the backlight drive circuit 32 may specifically include multiple (n) current output channels CH (channels, CH1, CH2...CHn), wherein each current output channel is controlled by a respective control signal (for example, pulse width modulation (pulse width modulation, PWM) signal), current can be supplied to each backlight string Ls (Ls1, Ls2, Ls3...Lsn), so as to control the light emission of the light emitting units in the backlight string.
  • a control signal for example, pulse width modulation (pulse width modulation, PWM) signal
  • PWM pulse width modulation
  • the backlight driving circuit 32 can be implemented in the form of a chip, as shown in FIG. 7 , the PWM signal and each channel CH can pass through the output/input pins of the chip.
  • the backlight driving circuit 32 may include a circuit structure as shown in FIG. 8 that is equivalent to the number of backlight strings (ie, the number of channels). Specifically, the circuit includes a current source 321 , an operational amplifier U1 , a driving transistor Q1 , a resistor R1 and a resistor R FBx .
  • the first terminal of the current source 321 is coupled to the power supply terminal VDD (the power supply terminal VDD can be coupled to the voltage output terminal Vout of the power supply 31); the second terminal of the current source is coupled to the ground GND through the resistor R1, and the first terminal of the current source 321
  • the two terminals are coupled to the positive input terminal (+) of the operational amplifier U1, and the control terminal of the current source 321 is used to connect Receive the PWM signal;
  • the gate g of the drive transistor Q1 is coupled to the output terminal of the operational amplifier U1, the source s of the drive transistor Q1 is coupled to the ground GND through the resistor R FEx , and the source s of the drive transistor Q1 is coupled to the output terminal of the operational amplifier U1
  • the inverting input terminal (-), the drain d of the driving transistor Q1 is coupled to the cathode of a light string, and provides the channel voltage V CHx to the cathode of the light string.
  • FIG. 7 also shows a capacitor C LED1 connected in parallel with the backlight string Ls1.
  • a capacitor C CH is connected between each channel and the ground GND (only the capacitor C CH1 corresponding to the channel CH1 is shown in FIG. The cathode of the capacitor C CH1 ).
  • the current source usually including a metal-oxide half-field-effect transistor (metal-oxide field-effect transistor) -semiconductor field-effect transistor, MOSFET) will be integrated with the drive circuit of the current source in a chip. Therefore, this loss will be released in the form of heat on the chip, which will cause the chip to heat up and damage the chip in severe cases.
  • an embodiment of the present application provides a driving circuit for a light emitting device.
  • a backlight string Ls (wherein the backlight strings Ls1, Ls2, Ls3, ..., Lsn shown in FIG. It includes at least one light-emitting unit connected in series, for example, the light-emitting unit may be an LED in FIG. 10 .
  • the backlight driving circuit comprises: a control circuit 43, at least one driving circuit 42 (wherein FIG. Current sources 44 - 1 , 44 - 2 , 44 - 3 , . . . , 44 -n) are shown in FIG. 10 .
  • the first end of the current source 44 is coupled to the cathode of the backlight string Ls, and the anode of the backlight string Ls is coupled to the power supply 41 (for example, coupled to the output terminal Vout of the power supply in FIG. 10); the second end of the current source 44 is coupled to the ground GND; the drive circuit 42 is coupled to the control terminal of the current source 41 ; the control circuit 43 is coupled to the drive circuit 42 , and the control circuit 43 is also coupled to the first terminal of the current source 44 or the control terminal of the current source 44 .
  • the control circuit 43 is configured to detect the electrical signal of the first terminal of the current source 44 (as shown in FIG. 10 ) or the control terminal of the current source 44 (as shown in FIG. 11 ); the control circuit 43 is also configured to The signal outputs a control signal to the driving circuit 42; the driving circuit 42 is configured to adjust the current flowing through the first terminal and the second terminal of the current source 44 and the voltage of the first terminal of the current source 44 according to the control signal.
  • control circuit can adjust the current flowing through the first terminal and the second terminal of the current source according to the electrical signal of the first terminal of the current source or the control terminal of the current source, and the voltage at the first terminal of the current source; in this way, the current source can be adjusted by detecting the electrical signal at the first terminal of the current source or the control terminal of the current source to dynamically adjust the current flowing through the first terminal and the second terminal of the current source, and The voltage at the first end of the current source avoids excessive loss when the current source supplies current to its corresponding backlight string.
  • the control circuit 43 can be a logic function circuit such as CPU, MCU, FPGA, and it has multiple input/output (input/output, I/O) interfaces, and these interfaces can carry out input or output of digital signals or analog signals, and Some functional processing is performed according to the input signal.
  • the above electrical signal may be judged and a control signal may be generated according to the judgment result.
  • the above-mentioned threshold value may be a preset default value inside the control circuit, or the threshold value is also the minimum value of the voltage corresponding to each electrical signal detected by the control circuit.
  • control circuit 43 determines that the voltage corresponding to the electrical signal is greater than the first threshold, the control circuit controls the drive circuit 42 through the control signal to increase the current flowing through the first end and the second end of the current source 44, and reduce the current flow of the current source 44.
  • the voltage of the first terminal of 44 is the control circuit 43 .
  • the control circuit determines that the corresponding voltage is greater than the threshold according to the electrical signal of the first terminal of a certain current source or the control terminal of the current source, it indicates that the voltage of the first terminal of the current source is too high, that is, the current source is in the direction of
  • the corresponding backlight string provides current, excessive loss occurs, and if the voltage at the first end of the current source 44 is directly reduced by reducing the current, it may not be possible to ensure that the backlight string connected to the current source is normal.
  • the control circuit determines that the electrical signal is greater than the first threshold, the control circuit controls the drive circuit through the control signal to increase the current flowing through the first end and the second end of the current source, and reduce the current The voltage of the first end of the source; thus while ensuring the normal lighting of the backlight string, since the voltage of the first end of the current source is reduced, the loss generated on the current source is also reduced, thereby reducing the overall backlight driving circuit loss.
  • the voltage of the first terminal of the current source 44 may also be increased according to the needs of actual scenarios, while the current flowing through the first terminal and the second terminal of the current source 44 may be decreased.
  • control circuit 44 determines that the voltage corresponding to the electrical signal is less than the second threshold, the control circuit controls the driving circuit to reduce the current flowing through the first end and the second end of the current source through the control signal, and increase the first end of the current source. terminal voltage.
  • control circuit 44 adjusts (reduces or increases) the voltage at the first end of the current source, it may be adjusted according to a certain step size, and different step sizes may be set according to different application scenarios, for example For mobile phones with low power consumption, you can set a smaller step size; for large-screen devices with high power consumption, you can set a larger step size; in order to ensure the adjustment accuracy as much as possible and shorten the time for adjusting the voltage.
  • the control circuit 44 determines that the voltage at the first end of the current source is less than or equal to the first threshold for the first time after a certain voltage adjustment, the adjustment is stopped.
  • the voltage at the first terminal of the current source is increased according to a certain step size, it can be understood that the voltage at the first terminal of the current source will gradually approach the second threshold.
  • the control circuit 44 determines that the voltage at the first end of the current source is greater than or equal to the second threshold for the first time after a certain voltage adjustment, the adjustment is stopped.
  • the step size is set larger, when the voltage at the first end of the current source is adjusted down according to the step size, if the voltage at the first end of the current source is lower than the first threshold for the first time after a certain adjustment, then you can also The voltage at the first end of the current source is increased by using a smaller step size, so that the voltage at the first end of the current source is closer to the first threshold.
  • the voltage at the first terminal of the current source is increased according to the step size
  • the voltage at the first terminal of the current source after adjustment is greater than the second threshold for the first time
  • it can also be adjusted according to A smaller step size reduces the voltage at the first end of the current source, so that the voltage at the first end of the current source is closer to the second threshold, where the first threshold and the second threshold can be the same value or different values value.
  • the driving circuit 42-1 includes an operational amplifier U11 and a switch K11
  • the driving circuit 42-2 includes an operational amplifier U21 and a switch K21
  • the driving circuit 42-3 includes an operational amplifier U31 and a switch K31
  • the driving circuit 42-n includes an operational amplifier Un1 And switch Kn1
  • Current source 44-1 includes driving transistor Q11 and resistance R11
  • current source 44-2 includes driving transistor Q21 and resistance R21
  • current source 44-3 includes driving transistor Q31 and resistance R31
  • current source 44-n includes driving Transistor Qn1 and resistor Rn1.
  • the first end of the drive transistor Q11 is coupled to the first end of the current source 44-1, and the second end of the drive transistor Q11 is coupled to the second end of the current source 44-1 (ie ground GND) through the resistor R11.
  • the control of the drive transistor Q11 The terminal is coupled to the control terminal of the current source 44-1.
  • the non-inverting input terminal (+) of the operational amplifier U11 is coupled to the control circuit 43, and the inverting input terminal (-) of the operational amplifier U11 is coupled to the second terminal of the driving transistor Q11.
  • the output terminal of the operational amplifier U11 is coupled to the first terminal of the switch K11, and the second terminal of the switch K11 is coupled to the control terminal of the driving transistor Q11.
  • the control signal includes a voltage signal Vset (Vset11, Vset21, Vset31...Vsetn1) and a switch control signal PWM (PWM11, PWM21, PWM31...PWMn1); the positive input terminal (+) of the operational amplifier U11 is configured to receive the voltage signal Vset11 , the control terminal of the switch K11 is configured to receive the switch control signal PWM11; wherein, when the switch control signal PWM11 turns the switch on, the voltage signal Vset11 is used to control the current flowing through the first terminal and the second terminal of the driving transistor Q11 (ie Flowing through the circuit I Ls1 of the light string Ls1 ), the switch control signal PWM11 is used to control the voltage of the first terminal of the driving transistor Q11 (ie, the channel voltage V CH1 of the light string Ls1 ).
  • the driving transistors Q11 , Q21 , Q31 , . . . , Qn1 are all N-type transistors.
  • the first terminal of the driving transistor Q11 is the d pole
  • the second terminal is the s pole
  • the control terminal is the g pole.
  • the s pole is directly connected to the ground GND (a fixed value) through the resistor R11, and it can be turned on only by making the g pole voltage higher than the s pole voltage, for example, the voltage fixed to Vin or Vout can be turned on , the current flows from the d pole to the s pole when it is turned on; the circuit design is relatively simple.
  • the drive transistors Q11, Q21, Q31, ..., Qn1 are all P-type transistors, then the d pole of the drive transistor Q11 needs to be connected to the ground through R11, and the current flows from the s pole to the d pole when it is turned on.
  • the voltage of the s pole is not fixed (depending on the voltage division of the backlight string), and the g pole voltage for controlling the conduction of the drive transistor Q11 cannot be determined, so an isolated power supply control or a bootstrap boost circuit needs to be designed separately.
  • Vout V Ls1 +V CH1 , Formula 1; where, V LS1 is the divided voltage of the backlight string Ls1, and V CH1 is the voltage of the d-pole of Q11;
  • V Ls1 VF1+VF2+VF3+...VFm, Formula 2; m is the number of LEDs on the backlight string LS1, and VF is the forward conduction voltage drop of the LEDs;
  • I Ls1 Vset11/R11, Formula 3; I Ls1 is the current of the backlight string Ls1;
  • Vset11 V CH1 ⁇ D PWM11 , Formula 4;
  • D PWM11 is the duty ratio of switch control signal PWM11;
  • I I 0 exp(qVF/nkT-1), Formula 5; q, n, k and T are constants, and I 0 is the reverse saturation current of LED;
  • Vset11 when V CH1 is high, Vset11 can be adjusted and increased, and it can be concluded from formula 3 that this will lead to an increase in I Ls1 .
  • I Ls1 when I Ls1 increases, VF becomes larger.
  • V Ls1 can be obtained from Formula 2 will become larger.
  • Equation 4 since Vset11 increases and V CH1 decreases, in order to balance Equation 4, it is necessary to increase D PWM11 .
  • the current I Ls1 of the backlight string can be increased or maintained to ensure normal light emission, while reducing V CH1 , thereby reducing the overall loss of the backlight driving circuit.
  • Vset11 when V CH1 is small, if it is necessary to increase V CH1 , Vset11 can also be adjusted to decrease, and D PWM11 can also be decreased.
  • the above description mainly takes the detection of V CH1 by the control circuit 43 as an example.
  • the relationship between the g-pole voltage and the d-pole voltage of Q11 is fixed; therefore, since the g-pole voltage of Q11 reflects the d-pole voltage, Therefore, the g-pole voltage can also be used as the above electrical signal, and when the g-pole voltage is greater than the threshold (where it can be understood that the thresholds set for the g-pole and d-pole are different), it just reflects that V CH1 is higher.
  • the switch K11 includes: a transistor Q12 and a transistor Q13; the first terminal of the transistor Q12 is coupled to the ground GND, the second terminal of the transistor Q12 is coupled to the control terminal of the transistor Q13, and the control terminal of the transistor Q12 is coupled to In the control circuit 43; the first terminal of the transistor Q13 is coupled to the output terminal of the operational amplifier U11, the second terminal of the transistor Q13 is coupled to the control terminal of the drive transistor Q11, and the control terminal of the transistor Q13 is also coupled to the operational amplifier U11 through a resistor R12 output end; transistor Q12, configured to periodically turn on the first end and second end of transistor Q12 under the control of switch control signal Vset11; transistor Q13, configured to connect the first end of transistor Q12 to the second end When the terminal is turned on, the first terminal and the second terminal of the transistor Q13 are turned on, so as to transmit the signal from the output terminal of the operational amplifier U11 to the control terminal of the driving transistor Q11.
  • the transistor Q12 may be an N-type transistor, and the Q13 may be a P-type transistor, wherein when the transistor Q12 is an N-type transistor, the s pole serves as the first terminal, the d pole serves as the second terminal, and the g pole serves as the control terminal; the transistor Q13 When it can be a P-type transistor, the s pole is used as the first terminal, the d pole is used as the second terminal, and the g pole is used as the control terminal; in this way, when Q12 is turned on, the current flows from the d pole to the s pole, and when Q13 is turned on, the current flows from the s pole The pole flows to the d pole, and the s pole of Q12 is connected to the ground GND to a fixed voltage, which is convenient for circuit design, and when Q12 is turned on, the resistor R12 provides a fixed voltage difference between the s pole and the g pole of Q13, as long as the voltage of the s pole is greater than g pole, and the conduction of
  • the backlight driving circuit further includes: a bandgap reference source 45 ( 45 - 1 , 45 - 2 , 45 - 3 , . . . , 45 -n).
  • the bandgap reference source 45-1 is connected between the drive circuit 42-1 and the control circuit 43;
  • the bandgap reference source 45-2 is connected between the drive circuit 42-2 and the control circuit 43;
  • the bandgap reference source 45 - 3 is connected between the drive circuit 42 - 3 and the control circuit 43 ;
  • the bandgap reference source 45 - n is connected between the drive circuit 42 - n and the control circuit 43 .
  • the bandgap reference sources 45 (45-1, 45-2, 45-3, ..., 45-n) are configured to adjust the voltage signal Vset (Vset11, Vset21, Vset31, ..., Vsetn1) according to a predetermined ratio.
  • the control circuit 43 shown in FIG. 15 is to detect the electrical signal of the first end of the current source 44; as shown in FIG. The scheme of the electrical signal at the terminal.
  • a specific structural schematic diagram of a bandgap reference source 45 including: transistors Q14, Q15, Q16, operational amplifier U13, resistors R13 and R14; wherein, the first end of Q15 is connected to the power supply terminal VCC , The first terminal of Q16 is connected to the power supply terminal VCC; the control terminal of Q15 is connected to the control terminal of Q16, the second terminal of Q15 is connected to the control terminal of Q15 and the first terminal of Q14, and the second terminal of Q14 is connected to the ground GND through a resistor R13;
  • the positive input terminal (+) of the amplifier is connected to the control circuit 43 for receiving the voltage signal Vset11; the negative input terminal (-) of the operational amplifier U13 is connected to the ground GND; the second terminal of Q16 is connected to the drive circuit 42-1 through a resistor R14 (Specifically connect to the positive input terminal (+) of the operational amplifier U11 of the driving circuit 42-1).
  • the bandgap reference source 45 can adjust the ratio of Vset11 to the voltage output to the drive circuit 42-1 according to the proportional relationship between the resistors R13 and R14; , the voltage signal output to the positive input terminal (+) of the operational amplifier U11 can be adjusted to a smaller step size (for example, 10mv) by adjusting the proportional relationship between the resistors R13 and R14.
  • a smaller step size for example, 10mv
  • Q15 and Q16 can use P-type transistors
  • Q14 can use N-type transistors.
  • the s pole When the transistor Q14 is an N-type transistor, the s pole is used as the second terminal, and the d pole is used as the first terminal.
  • the g pole serves as the control terminal; when the transistors Q15 and Q16 are P-type transistors, the s pole serves as the first terminal, the d pole serves as the second terminal, and the g pole serves as the control terminal.
  • each sub-light board of the backlight module needs to provide backlight strings with 16, 32, 48 or even more channels.
  • the control circuit 43 when the control circuit 43 cannot provide ports corresponding to the number of channels to realize the detection of the electrical signal at the first end or the control end of the current source 44, as shown in FIG.
  • the backlight driving circuit provided by the embodiment of the application further includes: a selector 46, wherein the selector 46 includes a plurality of input terminals, an output terminal and at least one control terminal, each current source 44 (44-1, 44-2, 44- 3, ..., 44-n) the first terminal or the control terminal of the current source is coupled to the input terminal of the selector 46, the output terminal of the selector 46 is coupled to the control circuit 43, and at least one control terminal of the selector 46 is coupled to The control circuit 43; the control circuit 43 is configured to output a gating control signal to the selector 46 through at least one control terminal of the selector 46; the selector 46 is configured to switch any input of the selector 46 according to the gating control signal terminal and the output terminal of the selector 46 are conducted.
  • a selector 46 includes a plurality of input terminals, an output terminal and at least one control terminal, each current source 44 (44-1, 44-2, 44- 3, ..., 44-n) the first terminal or the control terminal of the current source is
  • the selector 46 may include four input terminals and two control terminals.
  • the control circuit 43 can input a two-digit binary code to the two control terminals to realize the gating control of the selector 46 .
  • control circuit 43 inputs the binary code 00 to the selector 46 through two control terminals, and the selector 46 conducts the first input terminal and the output terminal, so that the first current source 44-1 connected to the backlight string Ls1 One end is connected with the control circuit 43 to realize the detection of the electrical signal of the first end of the current source 44-1;
  • control circuit 43 inputs the binary code 01 to the selector 46 through two control terminals, and the selector 46 selects the second The first input end and the output end are turned on, so that the first end of the current source 44-2 connected to the backlight string Ls2 is turned on with the control circuit 43, so as to realize the detection of the electrical signal at the first end of the current source 44-2;
  • the control circuit 43 inputs the binary code 10 to the selector 46 through two control terminals, and the selector 46 conducts the third input terminal and the output terminal, so that the first terminal of the current source 44-3 connected to the backlight string Ls3 Conducted with the control circuit 43 to realize the detection of the electrical signal of the first end of
  • control circuit 43 shown in Fig. 18 is the electric signal of the first end of detection current source 44; As shown in Fig. 19, this selector 46 also can be applied to the control of control circuit 43 detection current source 44 The scheme of the electrical signal at the terminal.
  • control circuit 43 mainly detects the signal of the first terminal or the control terminal of the current source 44 in the analog domain, that is, directly detects the analog signal of the first terminal or the control terminal of the current source 44 .
  • control circuit 43 can also detect the signal of the first terminal or the control terminal of the current source 44 in the digital domain.
  • the backlight driving circuit further includes: at least one comparator ( U12 , U22 , U32 , . . . , Un2 ) and a reference voltage generation circuit 47 .
  • the positive input terminal of U12 is coupled to the first terminal of the current source 44-1 or the control terminal of the current source 44-1, and the negative input terminal of the comparator U12 is coupled to the reference voltage generating circuit 47; the output terminal coupling control circuit 43 of the comparator U12; the reference voltage generation circuit 47, configured to generate a first reference voltage Vref; the comparator U12, configured to compare the voltage of the first end of the current source 44-1 with the first A reference voltage Vref is compared, or the control terminal voltage of the current source 44 - 1 is compared with the first reference voltage Vref, and the comparison result is output at the output terminal of the comparator U12 .
  • the comparison result 1 is output, otherwise the comparison result 0 is output;
  • the control circuit 43 is configured to determine the electrical signal of the first terminal of the current source 44-1 or the control terminal of the current source 44-1 according to the comparison result.
  • the control circuit 43 can control the reference voltage generation circuit 47 to maintain the first reference voltage Vref, and adjust the first terminal or the first terminal of the other current source 44 by adjusting the Vset and PDM of the drive circuit connected to the other current source 44.
  • the above is based on the voltage of the first terminal of a certain current source 44 (or the voltage of the control terminal) to adjust the voltage of the first terminal of other current sources 44 (or the voltage of the control terminal); of course, in order to make all the current sources 44
  • the voltage at the first terminal (or the voltage at the control terminal) is stable at a specified voltage, and the first reference voltage Vref can also be configured as the specified voltage.
  • the control circuit 43 shown in FIG. 20 detects the electrical signal at the first end of the current source 44; as shown in FIG. 21 , the control circuit 43 detects the signal at the first end or the control end of the current source 44 in the digital domain It can also be applied to the scheme that the control circuit 43 detects the electrical signal of the control terminal of the current source 44 .
  • a first chip CS1 is provided, which is applied to a backlight module.
  • At least one backlight string is provided on the lamp board of the backlight module, and the backlight string includes at least one light-emitting unit connected in series; wherein the The first chip CS1 includes: the above-mentioned at least one driving circuit 42 and at least one current source 44; in combination with the connection mode in FIG. 10 and FIG.
  • the anode of the light string Ls is coupled to the power supply 41; the second terminal of the current source 44 is used to couple to the ground GND; the driving circuit 42 is coupled to the control terminal of the current source 44; the driving circuit 42 is also coupled to the control circuit 43; the current source The first end of 44 or the control end of the current source 44 is also used to be coupled to the control circuit 43; wherein, the functions of the drive circuit 42, the control circuit 43 and the current source 44 can refer to the above examples and will not be repeated.
  • the package structure of the first chip CS1 provided with reference to FIG. 22 further includes input pins (Pin-Pinx) and output pins (pout1-poutn). In the example shown in FIG.
  • a second chip CS2 is also provided, wherein the second chip CS2 includes the above-mentioned control circuit 43, wherein the function and connection mode of the control circuit 43 refer to the descriptions of the above-mentioned FIG. 10 and FIG. 11, here I won't repeat them here.
  • the input pins (Pin-Pinm) of the first chip CS1 are connected with the output pins (pout1-poutm) of the second chip CS2 one by one, providing the connection between the control circuit 43 and each driving circuit 42; the first chip CS1
  • the output pins (pout1-poutn) of the second chip CS2 are respectively connected to the cathode of a backlight string Ls (Ls1-Lsn)
  • the input pins (Pin-Pinn) of the second chip CS2 are respectively connected to the cathode Ls of a backlight string (Ls1-Lsn ).
  • the first chip CS1 also includes external pins (pg1-pgn), wherein each external pin (pg1-pgn) is connected to a control terminal of a current source (that is, the g-pole of the driving transistor).
  • the input pins (Pin-Pinn) of the second chip CS2 are respectively connected to the external pins (pg1-pgn) of the first chip CS1, so as to realize the detection scheme of the electrical signal of the control terminal of each current source.
  • the backlight driving circuit also includes one or more components in the above-mentioned gap reference source 45, selector 46, comparator (U12, U22, . . . , Un2) and reference voltage generating circuit 47
  • it can also be Optionally integrated in the first chip CS1 or the second chip CS2.
  • the gap reference source 45 can be integrated in the first chip CS1
  • the selector 46, comparators (U12, U22, . . . , Un2) and the reference voltage generation circuit 47 can be integrated in the second chip CS2.
  • the second chip CS2 can also be integrated with the first chip CS1, so that the first chip CS1 includes at least one driving circuit 42, a control circuit 43 and at least one current source44.
  • the functions of the driving circuit 42 , the control circuit 43 and the current source 44 can refer to the above examples and will not be repeated.
  • the packaging structure of the first chip CS1 provided in FIG. 24 it includes pins (Pi/o1-Pi/on), wherein each pin (Pi/o1-Pi/on) is connected to the cathode of a light string , to provide the connection between the backlight driving circuit and each backlight string.
  • the backlight driving circuit also includes one or more components in the above-mentioned gap reference source 45, selector 46, comparator (U12, U22, . . . , Un2) and reference voltage generating circuit 47, it can also be Optionally integrated in the first chip CS1.

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Abstract

一种背光驱动电路（32）、芯片、背光模组（210）及电子设备（100），涉及显示技术领域，能够降低背光驱动电路（32）的损耗。背光驱动电路（32），应用于背光模组（210），背光模组（210）的灯板（213）上设置有至少一条背光灯串（Ls）；电流源（44）的第一端耦合于背光灯串（Ls）的阴极，背光灯串（Ls）的阳极耦合于电源（41）；电流源（44）的第二端耦合于地（GND）；控制电路（43），被配置为检测电流源（44）的第一端或者电流源（44）的控制端的电学信号；根据电学信号向驱动电路（42）输出控制信号；驱动电路（42），被配置为根据控制信号调整电流源（44）的第一端与第二端流经的电流，以及电流源（44）的第一端的电压。

Description

背光驱动电路、芯片、背光模组及电子设备
本申请要求于2022年03月04日提交国家知识产权局、申请号为202210212000.2、申请名称为“背光驱动电路、芯片、背光模组及电子设备”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
本申请实施例涉及显示技术领域，尤其涉及一种背光驱动电路、芯片、背光模组及电子设备。
背景技术
目前，液晶显示领域采用背光模组为液晶面板提供背光，其中，主流的背光方案包括全局控光以及局部亮度调整(local dimming，或称局部调/控光)技术。随着背光的技术演进，迷你发光二极管(mini light-emitting diode，mini LED)被广泛应用于背光面板作为灯串的发光单元用来背光光源。尤其在局部亮度调整技术中,可根据屏幕画面各处的亮暗场，实时控制对应背光区域的开关及亮度调节，使画面中黑色更黑，白色更白，色彩更自然艳丽，视觉的逼真感带来身临其境的最佳体验。mini LED背光方案通常使用较多的通道CH(channel，通常每个通道对应一个背光灯串(包括多个串联的LED)，背光驱动电路通过向每个通道提供电流以驱动对应的背光灯串发光)驱动很多个LED，功率等级较大。屏幕尺寸越大，亮度越高，背光通道数目也越多，以满足高动态范围600(high dynamic range 600，HDR600)、HDR1000、HDR vivid等标准。最终，背光的功率等级也越来越高，通常电视产品的背光功耗，要达到几百瓦,算上电源转换效率，功率损耗不可忽视。
然而，LED的正向导通电压(voltage forward，VF)与电流的关系是，电压越高，导通的电流越大。相同导通电流下，LED因为制程、材料原因，导致LED的VF也不相同。这样，由于LED的制程差异，最终导致LED的VF不同，各个通道的电压(通常通道的电压VCHx为背光灯串的阳极电压Vout与灯串的电压降VLS(灯串上串联的LED的VF之和)之差)也不相同。由于通道间各个LED的VF各不相同，因此在流经相同的电流ILED下，每个通道连接的背光灯串的总正向导通电压(即VLS)不同，导致各个通道的电压VCHx也各不相同。这样，当某一通道的电压VCHx较高时，则会提高背光驱动电路的损耗。此外，由于mini LED背光使用了较多通道，为节省布板布局面积，一般背光驱动电路中在各个通道上向背光灯串提供电流的电流源(通常包括金氧半场效晶体管(metal-oxide-semiconductor field-effect transistor,MOSFET)会与电流源的驱动电路集成在一个芯片内部。因此，这种损耗在芯片上会以热量的方式释放，进而导致芯片发热，严重时损坏芯片。
发明内容
本申请的实施例提供一种背光驱动电路、芯片、背光模组及电子设备，能够降低背光驱动电路的损耗。
第一方面，提供一种背光驱动电路。该背光驱动电路应用于背光模组，背光模组的灯板上设置有至少一条背光灯串,背光灯串包括至少一个串联的发光单元；背光驱动 电路包括：控制电路、至少一个驱动电路以及至少一个电流源。电流源的第一端用于耦合于背光灯串的阴极，背光灯串的阳极用于耦合于电源；电流源的第二端用于耦合于地；驱动电路耦合于电流源的控制端；控制电路耦合于所述驱动电路，控制电路还耦合于电流源的第一端或者电流源的控制端；控制电路，被配置为检测电流源的第一端或者电流源的控制端的电学信号；控制电路，还被配置为根据电学信号向驱动电路输出控制信号；驱动电路，被配置为根据控制信号调整电流源的第一端与第二端流经的电流，以及电流源的第一端的电压。这样，可以通过检测电流源的第一端或者电流源的控制端的电学信号调整电流源动态调整电流源的第一端与第二端流经的电流，以及电流源的第一端的电压，避免电流源在向其对应的背光灯串提供电流时，产生了过高的损耗。
在一种可能的实现方式中，驱动电路包括运算放大器以及第一开关；电流源包括驱动晶体管以及第一电阻；驱动晶体管的第一端耦合所述电流源的第一端，驱动晶体管的第二端通过第一电阻耦合至电流源的第二端，驱动晶体管的控制端耦合电流源的控制端；运算放大器的正向输入端耦合至所述控制电路，运算放大器的反向输入端耦合至驱动晶体管的第二端；运算放大器的输出端耦合至第一开关的第一端，第一开关的第二端耦合至驱动晶体管的控制端；控制信号包括电压信号以及开关控制信号；运算放大器的正向输入端被配置为接收电压信号，第一开关的控制端被配置为接收开关控制信号；其中，当开关控制信号将第一开关导通时，电压信号用于控制流经驱动晶体管的第一端和第二端的电流，开关控制信号用于控制驱动晶体管的第一端的电压。
在一种可能的实现方式中，若控制电路确定电学信号对应的电压大于第一阈值，所述控制电路通过控制信号控制驱动电路提高电流源的第一端与第二端流经的电流，并降低电流源的第一端的电压。这样，当控制电路根据某一个电流源的第一端或者电流源的控制端的电学信号确定对应的电压大于阈值时，则表征该电流源的第一端的电压过高，即该电流源在向其对应的背光灯串提供电流时，产生了过高的损耗，而如果直接通过降低电流的方式降低该电流源的第一端的电压，则可能不能保证该电流源连接的背光灯串正常发光，因此在本申请的方案中，控制电路确定电学信号大于第一阈值，所述控制电路通过控制信号控制驱动电路提高电流源的第一端与第二端流经的电流，并降低电流源的第一端的电压；从而在确保背光灯串正常发光的同时，由于降低了电流源的第一端的电压，因此也降低了该电流源上产生的损耗，进而降低了背光驱动电路整体的损耗。
在一种可能的实现方式中，控制电路确定所述电学信号对应的电压小于第二阈值，所述控制电路通过控制信号控制驱动电路降低电流源的第一端与第二端流经的电流，并提高电流源的第一端的电压。这样，在本申请的实施例中也提供了有调高电流源的第一端的电压，而降低电流源的第一端与第二端流经的电流的需求的应用场景。需要说明的，当控制电路对电流源的第一端的电压进行调整(降低或提高)时，可以是按照一定的步长进行调整，根据应用场景的不同，可以设置不同的步长，例如对于低功耗的手机，可以设置较小的步长；对于高功耗的大屏设备，可以设置较大的步长；以尽量确保调整的精度的同时缩短调整电压的时间。
在一种可能的实现方式中，还包括：带隙性基准源，带隙性基准源连接于驱动电 路与控制电路之间；带隙性基准源，被配置为按照预定比例调整电压信号。这样，在控制背光灯串的电流时，由于带隙性基准源可以按照预定比例调整电压信号，因此可以实现更小的电流精度，从而可以实现更精确的背光亮度调整。
在一种可能的实现方式中，第一开关包括：第一晶体管和第二晶体管；第一晶体管的第一端耦合于地，第一晶体管的第二端耦合于第二晶体管的控制端，第一晶体管的控制端耦合于控制电路；第二晶体管的第一端耦合于运算放大器的输出端，第二晶体管的第二端耦合于驱动晶体管的控制端，第二晶体管的控制端还通过第二电阻耦合于运算放大器的输出端；第一晶体管，被配置为在开关控制信号的控制下周期性的将第一晶体管的第一端和第一晶体管的第二端导通；第二晶体管，被配置为在第一晶体管的第一端与第一晶体管的第二端导通时，将第二晶体管的第一端与第二晶体管的第二端导通，以将运算放大器的输出端的信号传输至驱动晶体管的控制端。在该方案中提供了一种第一开关的具体实现方式，当然，可以理解的是该第一开关也可以采用其他形式。
在一种可能的实现方式中，第一晶体管包括N型晶体管，第二晶体管包括P型晶体管；第一晶体管的第一端为N型晶体管的源极；第一晶体管的第二端为N型晶体管的漏极，第一晶体管的控制端为N型晶体管的栅极；第二晶体管的第一端为P型晶体管的源极；第二晶体管的第二端为所述P型晶体管的漏极，第二晶体管的控制端为P型晶体管的栅极。这样，由于N型晶体管导通时，电流由漏极(drain，d)极流向源极(source，s)极，P型晶体管导通时电流由s极流向d极，并且N型晶体管的s极连接地GND为固定电压，便于电路设计，并且N型晶体管导通时，第二电阻给P型晶体管的s极和g极提供了固定的压差，只要s极的电压大于g极，并满足导通的阈值条件即可实现Q13的导通。
在一种可能的实现方式中，还包括：至少一个比较器以及参考电压生成电路；比较器的正向输入端耦合于电流源的第一端或者电流源的控制端，比较器的反向输入端耦合参考电压生成电路；比较器的输出端耦合控制电路；参考电压生成电路，被配置为生成第一参考电压；比较器，被配置为将电流源的第一端的电压与第一参考电压进行比较，或者将电流源的控制端电压与第一参考电压进行比较，在比较器的输出端输出比较结果；控制电路，被配置为根据比较结果确定电流源的第一端或者电流源的控制端的电学信号。这样，控制电路可以在数字域实现对电流源的第一端或控制端的信号进行检测。
在一种可能的实现方式中，还包括：选择器，其中选择器包括多个输入端、一个输出端以及至少一个控制端，电流源的第一端或电流源的控制端耦合至选择器的输入端，选择器的输出端耦合至控制电路，选择器的至少一个控制端耦合至控制电路；控制电路，被配置为通过选择器的至少一个控制端向选择器输出选通控制信号；选择器，被配置为根据选通控制信号将选择器的任一输入端与选择器的输出端导通。在一些场景下，背光模组的每个子灯板需要提供16、32、48甚至更多通道的背光灯串。受限于控制电路提供的端口数量的限制当控制电路不能提供对应通道数量的端口以实现上述的电流源的第一端或控制端的电学信号的检测时，可以采用该可能的实现方式提供的方案，如此，分时对各个电流源的第一端的电学信号进行检测，降低了控制电路的复 杂度。
第二方面，提供一种芯片，应用于背光模组，背光模组的灯板上设置有至少一条背光灯串,背光灯串包括至少一个串联的发光单元；芯片包括：至少一个驱动电路以及至少一个电流源；电流源的第一端，用于耦合于背光灯串的阴极，背光灯串的阳极耦合于电源；电流源的第二端，用于耦合于地；驱动电路，耦合于电流源的控制端；驱动电路还用于耦合于控制电路；电流源的第一端或者电流源的控制端，还用于耦合于控制电路；控制电路，被配置为检测电流源的第一端或者电流源的控制端的电学信号；控制电路，还被配置为根据电学信号向驱动电路输出控制信号；驱动电路，被配置为根据控制信号调整电流源的第一端与第二端流经的电流，以及电流源的第一端的电压。
在一种可能的实现方式中，驱动电路包括运算放大器以及第一开关；电流源包括驱动晶体管以及第一电阻；驱动晶体管的第一端耦合电流源的第一端，驱动晶体管的第二端通过第一电阻耦合至电流源的第二端，驱动晶体管的控制端耦合电流源的控制端；运算放大器的正向输入端耦合至控制电路，运算放大器的反向输入端耦合至驱动晶体管的第二端；运算放大器的输出端耦合至第一开关的第一端，第一开关的第二端耦合至驱动晶体管的控制端；控制信号包括电压信号以及开关控制信号；运算放大器的正向输入端被配置为接收电压信号，第一开关的控制端被配置为接收开关控制信号；其中，当开关控制信号将第一开关导通时，电压信号用于控制流经驱动晶体管的第一端和第二端的电流，开关控制信号用于控制驱动晶体管的第一端的电压。
在一种可能的实现方式中，若控制电路确定电学信号对应的电压大于第一阈值，所述控制电路通过控制信号控制驱动电路提高电流源的第一端与第二端流经的电流，并降低电流源的第一端的电压。
在一种可能的实现方式中，若控制电路确定电学信号对应的电压大于第二阈值，所述控制电路通过控制信号控制驱动电路减小电流源的第一端与第二端流经的电流，并提高电流源的第一端的电压。
在一种可能的实现方式中，还包括：带隙性基准源，带隙性基准源连接于运算放大器的正向输入端与控制电路之间；带隙性基准源，被配置为按照预定比例调整电压信号。
在一种可能的实现方式中，第一开关包括：第一晶体管和第二晶体管；第一晶体管的第一端耦合于地，第一晶体管的第二端耦合于第二晶体管的控制端，第一晶体管的控制端耦合于控制电路；第二晶体管的第一端耦合于运算放大器的输出端，第二晶体管的第二端耦合于驱动晶体管的控制端，第二晶体管的控制端还通过第二电阻耦合于运算放大器的输出端；第一晶体管，被配置为在开关控制信号的控制下周期性的将第一晶体管的第一端和第一晶体管的第二端导通；第二晶体管，被配置为在第一晶体管的第一端与第一晶体管的第二端导通时，将第二晶体管的第一端与第二晶体管的第二端导通，以将运算放大器的输出端的信号传输至驱动晶体管的控制端。
在一种可能的实现方式中，第一晶体管包括N型晶体管，第二晶体管包括P型晶体管；第一晶体管的第一端为N型晶体管的源极；第一晶体管的第二端为N型晶体管的漏极，第一晶体管的控制端为N型晶体管的栅极；第二晶体管的第一端为P型晶体管的源极；第二晶体管的第二端为P型晶体管的漏极，第二晶体管的控制端为P型晶 体管的栅极。
在一种可能的实现方式中，还包括：至少一个比较器以及参考电压生成电路；比较器的正向输入端耦合于电流源的第一端或者电流源的控制端，比较器的反向输入端耦合参考电压生成电路；比较器的输出端耦合控制电路；参考电压生成电路，被配置为生成第一参考电压；比较器，被配置为将电流源的第一端的电压与第一参考电压进行比较，或者将电流源的控制端电压与第一参考电压进行比较，在比较器的输出端输出比较结果；控制电路，被配置为根据所述比较结果确定电流源的第一端或者电流源的控制端的电学信号。
在一种可能的实现方式中，还包括：选择器，其中选择器包括多个输入端、一个输出端以及至少一个控制端，电流源的第一端或电流源的控制端耦合至选择器的输入端，选择器的输出端耦合至控制电路，选择器的至少一个控制端耦合至控制电路；控制电路，被配置为通过选择器的至少一个控制端向选择器输出选通控制信号；选择器，被配置为根据选通控制信号将选择器的任一输入端与选择器的输出端导通。
在一种可能的实现方式中，控制电路包含于芯片中。
第三方面，提供一种背光模组，背光模组包括背板、平整板、灯板、扩散板；其中，平整板位于背板和灯板之间，灯板位于平整板与所述扩散板之间；灯板上设置有至少一条背光灯串，背板上设置有上述的背光驱动电路，或上述的芯片。
第四方面，提供一种电子设备，包括上述的背光模组，以及设置于背光模组的液晶面板。
其中，第二方面、第三方面以及第四方面实现的技术效果可以参考第一方面或任意一种可能的实现方式中的描述，此处不再赘述。
附图说明
图1为本申请的实施例提供的一种电子设备的整体结构示意图；
图2为本申请的实施例提供的一种屏组件的爆炸结构示意图；
图3为本申请的实施例提供的一种子灯板的结构示意图；
图4为本申请的另一实施例提供的一种子灯板的结构示意图；
图5为本申请的实施例提供的一种连接器的结构示意图；
图6为本申请的实施例提供的一种控制模组与连接器的连接结构示意图；
图7为本申请的实施例提供的一种背光驱动电路的示意图；
图8为本申请的实施例提供的一种背光驱动电路的示意图；
图9为本申请的实施例提供的一种背光驱动电路的局部结构示意图；
图10为本申请的实施例提供的一种LED的电流和电压曲线示意图；
图11为本申请的另一实施例提供的一种背光驱动电路的示意图；
图12为本申请的又一实施例提供的一种背光驱动电路的示意图；
图13为本申请的另一实施例提供的一种背光驱动电路的局部结构示意图；
图14为本申请的又一实施例提供的一种背光驱动电路的局部结构示意图；
图15为本申请的再一实施例提供的一种背光驱动电路的示意图；
图16为本申请的另一实施例提供的一种背光驱动电路的示意图；
图17为本申请的再一实施例提供的一种背光驱动电路的局部结构示意图；
图18为本申请的又一实施例提供的一种背光驱动电路的示意图；
图19为本申请的再一实施例提供的一种背光驱动电路的示意图；
图20为本申请的另一实施例提供的一种背光驱动电路的示意图；
图21为本申请的又一实施例提供的一种背光驱动电路的示意图；
图22为本申请的再一实施例提供的一种背光驱动电路的示意图；
图23为本申请的实施例提供的一种芯片的示意图；
图24为本申请的另一实施例提供的一种芯片的示意图。
具体实施方式
下面将结合附图，对本申请一些实施例中的技术方案进行清楚、完整地描述，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。基于本申请所提供的实施例，本领域普通技术人员所获得的所有其他实施例，都属于本申请保护的范围。
除非上下文另有要求，否则，在整个说明书和权利要求书中，术语“包括(comprise)”及其其他形式例如第三人称单数形式“包括(comprises)”和现在分词形式“包括(comprising)”被解释为开放、包含的意思，即为“包含，但不限于”。在说明书的描述中，术语“一个实施例(one embodiment)”、“一些实施例(some embodiments)”、“示例性实施例(exemplary embodiments)”、“示例(example)”、“特定示例(specific example)”或“一些示例(some examples)”等旨在表明与该实施例或示例相关的特定特征、结构、材料或特性包括在本申请的至少一个实施例或示例中。上述术语的示意性表示不一定是指同一实施例或示例。此外，所述的特定特征、结构、材料或特点可以以任何适当方式包括在任何一个或多个实施例或示例中。
以下，术语“第一”、“第二”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”的特征可以明示或者隐含地包括一个或者更多个该特征。在本申请实施例的描述中，除非另有说明，“多个”的含义是两个或两个以上。另外，“基于”的使用意味着开放和包容性，因为“基于”一个或多个所述条件或值的过程、步骤、计算或其他动作在实践中可以基于额外条件或超出所述的值。
在本申请的描述中，需要理解的是，术语“中心”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、“外”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。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。
本申请的实施例提供的晶体管可以采用金氧半场效晶体管(Metal-Oxide-Semiconductor Field-Effect Transistor,MOSFET)。在本申请的实施例中，晶体管分为N(negative，负)型晶体管和P(positive，正)型晶体管两种类型。晶体管包括源极(source)、漏极(drain)以及栅极(gate)，通过控制输入晶体管栅极的电平,可以控制晶体管的导通(开启)或断开(关闭、截止、断路)。晶体管在开启时，源极和漏极导通，产生开启电流，并且，在晶体管的栅极电平不同时， 源极与漏极之间产生的开启电流的大小也不同；晶体管在关闭时，源极和漏极不会导通，不会产生电流。在本申请的实施例中，晶体管的栅极也被称为控制端，源极被称为第一端，漏极被称为第二端；或者，栅极被称为控制端，漏极被称为第一端，源极被称为第二端。此外，N型晶体管在控制端的电平为高电平时开启，第一端和第二端导通，第一端和第二端之间产生开启电流；N型晶体管在控制端的电平为低电平时关闭，第一端和第二端不导通，不产生电流。P型晶体管在控制端的电平为低电平时开启，第一端和第二端导通，产生开启电流；P型晶体管在控制端的电平为高电平时关闭，第一端和第二端不导通，不产生电流。以下方案中的开关所采用的晶体管均可以参照此处的描述。
下面将结合附图，对本申请中的技术方案进行描述。
图1是本申请实施例提供的一种电子设备100的结构示意图。电子设备100可以是广告屏(广告牌)、显示器、电视(TV，如智慧屏)、笔记本电脑、平板电脑、车载设备等屏类电子设备。可选的，在一些场景下，电子设备100可以是手机、电子阅读器或可穿戴设备等设备。图1所示实施例以电子设备100是电视为例进行说明。
电子设备100可以包括壳体110和屏组件200。
壳体110可以包括边框和后盖。边框可以环绕设于后盖的周缘。壳体110例如可以包括电子设备100的中框。在一个示例中，电子设备100的中框可以收容于边框的内周。在另一个示例中，电子设备100的中框可以充当壳体110的边框。屏组件200可以是为电子设备100提供显示功能的组件。用户可以观看屏组件200以欣赏图像、视频等媒体资源。屏组件200可以安装于壳体110上。屏组件200的周缘可以抵靠在边框的内沿。边框可以将屏组件200固定在壳体110上。屏组件200和后盖可以分别安装于边框的两侧，使得壳体110可以为电子设备内部的器件，尤其是屏组件200上的器件，提供机械保护的功能。屏组件200例如可以固定于电子设备100的中框上。
电子设备100还可以包括控制模组。控制模组的具体实现形式例如可以包括处理器、控制器、连接器、驱动板、集成电路、芯片、电源等。在本申请的实施例中，控制模组具体可以包含一种背光驱动电路，该背光驱动电路可以是芯片形式或者集成于驱动板等形式，此外在本申请的实施例中具体可以包括电源，以及背光驱动电路中的控制电路、驱动电路以及电流源中的一个或多个。屏组件200上例如可以配置有控制模组，该控制模组可以收容于壳体110内。在一个示例中，控制模组可以包括至少一个通信接口、总线、至少一个处理器和至少一个存储器。至少一个通信接口、至少一个处理器及至少一个存储器可通过总线相互通信。至少一个通信接口可以用于接收和发送信号。例如，屏组件200的发光单元可以连接其中一个通信接口，使得控制模组可以触发发光单元发光。至少一个存储器用于存储应用程序代码。应用程序代码例如可以包括控制发光单元发光或不发光的代码。至少一个处理器可以用于执行上述应用程序代码，以实现对发光单元的控制。本申请中，“至少一个”例如包括一个或多个两种情况。
下面结合图2，阐述本申请实施例提供的屏组件200。图2是屏组件200的爆炸图。其中在图2中示出的屏组件200包括背光模组210以及设置于背光模组210出光侧的液晶面板220。背光模组210可以包括层叠设置的背板211、平整板212、灯板213、 扩散板214、光学膜片215等部件。当然以上图2中只是示例性的提供了一种背光模组210的通用结构，在一些示例中背光模组210可能还包括比上述更多或者更少的部件。
背板211可以具有支撑电子设备100、为电子设备100内的电子元件提供机械保护等功能。背板211的材料可以是满足机械强度要求、可以起到支撑作用的材料。例如，背板211可以是不锈钢、铝合金、锌合金、钛合金等金属材料。又如，背板211可以是树脂等非金属材料。背板211可以包括第一背板端面和第二背板端面，第一背板端面靠近灯板213，第二背板端面远离灯板213。对于用户而言，第一背板端面可以对应电子设备100的正面，第二背板端面可以对应电子设备100的背面。电子设备100的正面可以是，在用户使用电子设备100时，电子设备100的经常被观察到的一侧。电子设备100的背面可以与电子设备100的正面相对设置，并且电子设备100的背面可以是，在用户使用电子设备100时，电子设备100的不常被观察到的一侧。例如，电子设备100可以是电视，电视的安装有屏组件的一侧可以是电视的正面；电视的安装有后盖的一侧可以是电视的背面。第一背板端面对应电子设备100的正面，可以指，沿用户观察电子设备100的正面的方向观察背板211，可以观察到第一背板端面。第二背板端面对应电子设备100的背面，可以指，沿用户观察电子设备100的背面的方向观察背板211，可以观察到第二背板端面。为便于描述，第一背板端面可以称作背板211的正面，第二背板端面可以称作背板211的背面。在一种可能的示例中，第一背板端面可以固定于壳体110的后盖上。例如，通过如螺钉、双面胶、泡棉等机械连接件，第一背板端面可以固定于壳体110的后盖上。在其他可能的示例中，背板211可以充当壳体110的后盖。
平整板212可以位于灯板213与背板211之间。平整板212可以用于为灯板213提供支撑，以维持或保证灯板213的平整度。平整板212可以是具有一定刚度的导电材料。例如平整板212可以为铝板。平整板212例如可以通过双面胶、泡棉等机械连接件，固定于背板211上。在一种可能的场景下，在电子设备100被运输的过程中，电子设备100可能会发生磕碰、跌落等情况。在此情况下，电子设备100可以承受一定程度的外力。背板211则可以相应地发生变形，以抵抗该外力。如果灯板213直接固定于背板211上，灯板213可能跟随背板211发生相对明显的变形。为了避免上述情况的发生会增大电子设备100的运输难度。如果背板211发生相对明显的变形，这不利于灯板213的显示效果。例如，由于灯板213的不同区域的混光距离不同，电子设备100可能发生明暗不均、重影等显示问题。将平整板212设置在背板211与灯板213之间，使得在变形量方面，平整板212可以在灯板213与背板211之间起过渡作用。平整板212的变形量可以小于背板211的变形量，进而灯板213的变形量可以有减小的趋势。也就是说，在背板211发生相对明显变形的情况下，灯板213的变形量可以尽可能相对小或尽可能相对不明显。
光学膜片215可以改变来自灯板213的光的频率。光学膜片215可以包括量子点。例如，灯板213可以发出高能量的蓝光；蓝光可以激发封装在光学膜片215内的量子点，从而量子点可以将灯板213发出的蓝光转换为白光(量子点可以是一种纳米级的半导体；通过对量子点施加一定的电场或光压，量子点可以发出特定频率的光)。量 子点例如可以形成于化学涂层、荧光粉在一个可能的示例中，自光学膜片215发出的光例如可以进入液晶面板220。液晶面板220可以包括液晶层和滤光层。液晶层的液晶可以控制液晶单元开启或关闭，以控制白光穿过液晶单元的光强。通过开启液晶单元，使得穿过液晶单元的白光可以照射滤光层上。滤光层可以包括红光滤光片、绿光滤光片、蓝光滤光片。红光滤光片可以用于将白光转换为红光。绿光滤光片可以用于将白光转换为绿光。蓝光滤光片可以用于将白光转换为蓝光。由此，可以控制电子设备100发出多种颜色的光，以显示彩色图案。
在其他示例中，扩散板214可以包括量子点，故扩散板214可以改变来自灯板213的光的频率。在一些实施例中，扩散板214可以与光学膜片215一体成型。灯板213发出的光可以仅经过混光处理，且不经过其他光学处理，并直接射入扩散板214。也就是说，在一些可能的场景中，在灯板213的发光单元上可以不配置量子点。这有利于降低灯板213的结构复杂度，有利于发光单元可以在灯板213上相对紧密地排布。例如，荧光粉的尺寸通常大于灯板213的发光单元的尺寸，将荧光粉封装于灯板213上，不利于发光单元的紧密排布。
在一些示例中，灯板213也可以包括多个阵列分布的子灯板2130。下面以一个子灯板2130为例进行说明。子灯板2130可以包括第一灯板端面2131和第二灯板端面2132。图3是本申请实施例提供的一种子灯板2130的第一灯板端面2131的示意性结构图。子灯板2130发出的光可以从子灯板2130的第一灯板端面2131射出。子灯板2130的第一灯板端面2131可以为子灯板2130的靠近扩散板214、远离背板211的表面。下面结合图3，阐述子灯板2130的第一灯板端面2131的结构。子灯板2130可以包括多个发光单元2133。例如，子灯板2130可以包括多个阵列排布的发光单元2133。发光单元2133例如可以是具有发光功能的芯片。发光单元2133还可以是发光二极管LED，其中位于同一列或同一行的若干个发光单元可以连接成一个背光灯串。图4是本申请实施例提供的一种子灯板2130的第二灯板端面2132的示意性结构图。子灯板2130的第二灯板端面2132可以靠近背板211、远离扩散板214设置。下面结合图4，阐述子灯板2130的第二灯板端面2132的结构。子灯板2130的第二灯板端面2132可以设置有双面胶，双面胶可以固定连接子灯板2130与平整板212。在一个可能的示例中，该双面胶可以是导热胶2134。由于子灯板2130工作时可能产生相对较高的热量，因此导热胶2134有利于将子灯板2130的热量转移至平整板212，有利于提升电子设备100的散热性。
子灯板2130的第二灯板端面2132还可以设置有导电弹片2135。导电弹片2135的一端可以与子灯板2130电连接。导电弹片2135的另一端可以抵接在平整板212上。在子灯板2130工作的情况下，子灯板2130的发光单元2133可以积累电荷。通过导电弹片2135可以使子灯板2130接地，进而有利于提升电子设备100的电磁兼容性(electromagnetic compatibility，EMC)。
子灯板2130还可以包括一个或多个背光驱动电路2136、一个或多个连接器2137。通过连接器2137，与子灯板2130相关的信号可以被输入至背光驱动电路2136以控制背光驱动电路2136向发光单元2133提供电流，从而控制发光单元2133的明暗状态，使得背光驱动电路2136可以根据控制信号，控制发光单元2133的明暗状态。其中， 在发光单元2133处于明亮状态的情况下，发光单元2133可以被背光驱动电路2136驱动。可选的，在发光单元2133处于明亮状态的情况下，发光单元2133的亮度可调。在发光单元2133处于暗淡状态的情况下，发光单元2133可以被背光驱动电路2136熄灭(即发光单元2133可以未被驱动)。
如图5提供的对连接器2137的局部放大图所示，在一个示例中，连接器2137可以包括多个连接器端口P(也称作引脚，pin)。例如，连接器2137可以包括30～100个连接器端口P。相应地，背光驱动电路2136可以包括与多个连接器端口对应的多个信号输入端口。多个连接器端口和多个信号输入端口可以通过一对一、一对多、多对应等方式电连接。连接器端口P可以用于传输与子灯板2130相关的信号。当然，在背光驱动电路2136设置于上述的控制模组时，也可通过连接器端口P向子灯板2130直接传输发光单元2133的电流。背光驱动电路2136可以用于驱动子灯板2130的一个或多个发光单元2133串联形成的背光灯串，以及控制子灯板2130的每个发光单元2133的发光。例如，背光驱动电路2136可以熄灭一条背光灯串中串联的一个或多个发光单元2133、控制一条背光灯串中串联的一个或多个发光单元2133的亮度等。当然，图6仅仅提供了一种示例，在一些方案中，并不限于将背光驱动电路2136全部设置于子灯板2130，或者将背光驱动电路2136中的部分结构或模块设置于子灯板2130，或者将背光驱动电路2136全部设置于控制模组217。
在一个示例中，控制模组217可以包括图7所示的电源31以及背光驱动电路32。其中，电源31可以采用开关电路，如图7所示，电源31的输入端口Vin可以耦合于电池或者外接适配器，以向开关电路提供输入电压；电源31的输出端口Vout可以耦接于各个灯串的阳极，以向各个灯串提供输出电压，此处开关电路具体用于将电源31的输入电压进行降压或升压变换后输出输出电压至输出端口Vout；示例性的，开关电路具体包括电感L1、二极管D1、开关晶体管M1以及电阻RCS，其中电感L1与二极管D1串联于输入端口Vin与输出端口Vout之间，其中，二极管D1的阳极与电感L1电连接，二极管D1的阴极与输出端口Vout电连接；开关晶体管M1的漏极(drain，d)与二极管D1的阳极电连接，开关晶体管M1的源极(source，s)通过电阻RCS连接地GND。这样，通过向开关晶体管M1的栅极(gate，g)输入开关信号，从而周期性控制开关晶体管M1的导通状态，从而实现电压的转换。如图7所示，背光驱动电路32具体可以包括多个(n)电流输出通道CH(channel，CH1、CH2……CHn)，其中每个电流输出通道分别在各自的控制信号(例如脉冲宽度调制(pulse width modulation，PWM)信号)的控制下，可以向各个背光灯串Ls(Ls1、Ls2、Ls3……Lsn)提供电流，以实现对背光灯串中的发光单元的发光控制。通常该背光驱动电路32可以以芯片形式实现，如图7所示，PWM信号以及各个通道CH可以通过芯片的输出/输入管脚。
如图8所示，提供了一种背光驱动电路32中，每一通道的电路的具体实现方式。该背光驱动电路32中可以包括与背光灯串数量(即通道数量)相当的如图8提供的电路结构。具体的，该电路包括电流源321、运算放大器U1、驱动晶体管Q1、电阻R1以及电阻RFBx。其中，电流源321的第一端耦合于电源端VDD(该电源端VDD可以耦合于电源31的电压输出端Vout)；电流源的第二端通过电阻R1耦合于地GND，电流源321的第二端耦合于运算放大器U1的正向输入端(+)，电流源321的控制端用于接 收PWM信号；驱动晶体管Q1的栅极g耦合于运算放大器U1的输出端，驱动晶体管Q1的源极s通过电阻RFEx耦合于地GND，并且驱动晶体管Q1的源极s耦合至运算放大器U1的反向输入端(-)，驱动晶体管Q1的漏极d耦合于一条灯串的阴极，并向灯串的阴极提供通道电压VCHx。这样，由于电阻R1与电阻RFBx满足关系R1/RFBx＝KIset；则当通过PWM信号控制调整电流源321输出的电流Iset时，运算放大器可以基于正向输入端(+)和反向输入端(-)的电压出VOS进行放大运算，以输出信号调整驱动晶体管Q1的导通状态，从而调整VCHx的大小以及流经灯串的电流ILED，其中Iset/ILED＝1/KIset。当然，为了确保向每个背光灯串的阳极与阴极之间提供稳定的电压，图7中还示出了与背光灯串Ls1并联的电容CLED1，当然，图7中虽然未示出其他背光灯串并联的电容，但应该理解，其他背光灯串也具有相应并联的电容。同理，为了确保背光驱动电路的通道输出电压的稳定性，各个通道与地GND之间连接有电容CCH(图7中也仅示出了通道CH1对应的电容CCH1，即与背光灯串的阴极连接的电容CCH1)。
然而，LED的VF与电流的关系是，电压越高，导通的电流越大(如图9所示)。并且相同导通电流下，LED因为制程、材料原因，导致不同的LED的VF也不相同。这样，由于LED的制程差异，最终导致LED的VF不同，各个通道的电压(通常通道的电压VCHx为灯串的阳极电压Vout与背光灯串的电压降VLS之差)也不相同。由于通道间各个LED的VF电压各不相同，因此在流经相同的电流ILED下，每个通道连接的背光灯串的总正向电压(即VLS)不同，导致各个通道的电压VCHx也各不相同。这样，当某一通道的电压VCHx较高时，则会提高背光驱动电路的损耗，其中通道的损耗功率P＝VCHx*ICHx(其中在串联电路上ICHx＝ILED)。此外，由于mini LED背光使用了较多通道，为节省布板布局面积，一般背光驱动电路中在各个通道上向背光灯串提供电流的电流源(通常包括金氧半场效晶体管(metal-oxide-semiconductor field-effect transistor,MOSFET)会与电流源的驱动电路集成在一个芯片内部。因此，这种损耗在芯片上会以热量的方式释放，进而导致芯片发热，严重时损坏芯片。
为解决上述问题，参照图10所示，本申请的实施例提供一种发光器件驱动电路。应用于上述的背光模组，背光模组的灯板上设置有至少一条背光灯串Ls(其中图10中示出的背光灯串Ls1、Ls2、Ls3、……、Lsn),背光灯串Ls包括至少一个串联的发光单元，例如发光单元可以是图10中的LED。背光驱动电路包括：控制电路43、至少一个驱动电路42(其中图10中示出驱动电路42-1、42-2、42-3、……、42-n)以及至少一个电流源44(其中图10中示出电流源44-1、44-2、44-3、……、44-n)。
电流源44的第一端耦合于背光灯串Ls的阴极，背光灯串Ls的阳极耦合于电源41(例如耦合于图10中电源的输出端Vout)；电流源44的第二端耦合于地GND；驱动电路42耦合于电流源41的控制端；控制电路43耦合于驱动电路42，控制电路43还耦合于电流源44的第一端或者电流源44的控制端。
控制电路43，被配置为检测电流源44的第一端(如图10所示)或者电流源44的控制端(如图11所示)的电学信号；控制电路43，还被配置为根据电学信号向驱动电路42输出控制信号；驱动电路42，被配置为根据控制信号调整电流源44的第一端与第二端流经的电流，以及电流源44的第一端的电压。由于控制电路可以根据电流源的第一端或者电流源的控制端的电学信号调整电流源的第一端与第二端流经的电流， 以及电流源的第一端的电压；这样，可以通过检测电流源的第一端或者电流源的控制端的电学信号调整电流源动态调整电流源的第一端与第二端流经的电流，以及电流源的第一端的电压，避免电流源在向其对应的背光灯串提供电流时，产生了过高的损耗。
其中，需要说明的是，由于电流源44受控于其控制端的电学信号，因此可以理解的是，电流源44的第一端的电学信号与电流源44的控制端的电学信号成固定比例关系，其具体比例的大小主要受限于电流源内部器件的参数选型。此外，控制电路43可以是CPU、MCU、FPGA等逻辑功能电路，其具有多个输入/输出(input/output,I/O)接口，这些接口可以进行数字信号或模拟信号的输入或输出，并根据输入的信号进行一些功能处理，例如，在实现本申请的实施例时，可以对上述电学信号进行判断并根据判断结果生成控制信号。其中上述的阈值可以是控制电路内部预设的默认值，或者阈值也是控制电路检测各个电学信号对应的电压的最小值。
具体的，若控制电路43确定电学信号对应的电压大于第一阈值，所述控制电路通过控制信号控制驱动电路42提高电流源44的第一端与第二端流经的电流，并降低电流源44的第一端的电压。这样，当控制电路根据某一个电流源的第一端或者电流源的控制端的电学信号确定对应的电压大于阈值时，则表征该电流源的第一端的电压过高，即该电流源在向其对应的背光灯串提供电流时，产生了过高的损耗，而如果直接通过降低电流的方式降低该电流源44的第一端的电压，则可能不能保证该电流源连接的背光灯串正常发光，因此在本申请的方案中，若控制电路确定电学信号大于第一阈值，所述控制电路通过控制信号控制驱动电路提高电流源的第一端与第二端流经的电流，并降低电流源的第一端的电压；从而在确保背光灯串正常发光的同时，由于降低了电流源的第一端的电压，因此也降低了该电流源上产生的损耗，进而降低了背光驱动电路整体的损耗。在一些示例中，根据实际场景的需要也可以调高电流源44的第一端的电压，而降低电流源44的第一端与第二端流经的电流。例如当控制电路44确定电学信号对应的电压小于第二阈值时，所述控制电路通过控制信号控制驱动电路降低电流源的第一端与第二端流经的电流，并提高电流源的第一端的电压。示例性的，当控制电路44对电流源的第一端的电压进行调整(降低或提高)时，可以是按照一定的步长进行调整，根据应用场景的不同，可以设置不同的步长，例如对于低功耗的手机，可以设置较小的步长；对于高功耗的大屏设备，可以设置较大的步长；以尽量确保调整的精度的同时缩短调整电压的时间。
此外，可以理解的是，当按照一定的步长调小电流源的第一端的电压时，可以理解的是电流源的第一端的电压会逐步向第一阈值逼近。这样，当控制电路44确定某一次调整电压后电流源的第一端的电压首次小于或等于第一阈值，则停止调整。又例如，当按照一定的步长调大电流源的第一端的电压时，可以理解的是电流源的第一端的电压会逐步向第二阈值逼近。这样，当控制电路44确定某一次调整电压后电流源的第一端的电压首次大于或等于第二阈值，则停止调整。当然，当步长设置的较大时，当按照步长调小电流源的第一端的电压时，如果某一次调整后电流源的第一端的电压首次小于第一阈值后，则也可以采用更小的步长调大电流源的第一端的电压，从而使得电流源的第一端的电压更加逼近第一阈值。当然，当按照步长调大电流源的第一端的电压时，如果某一次调整后电流源的第一端的电压后首次大于第二阈值，则也可以按照 更小的步长调小电流源的第一端的电压，从而使得电流源的第一端的电压更加逼近第二阈值其中，第一阈值与第二阈值可以是同一个取值或不同的取值。
结合图12所示，本申请的实施例提供的方案中，提供了驱动电路42以及电流源44的具体结构及其连接方式。其中，驱动电路42-1包括运算放大器U11以及开关K11、驱动电路42-2包括运算放大器U21以及开关K21、驱动电路42-3包括运算放大器U31以及开关K31、驱动电路42-n包括运算放大器Un1以及开关Kn1；电流源44-1包括驱动晶体管Q11以及电阻R11、电流源44-2包括驱动晶体管Q21以及电阻R21、电流源44-3包括驱动晶体管Q31以及电阻R31、电流源44-n包括驱动晶体管Qn1以及电阻Rn1。以下结合图12对驱动电路42-1以及电流源44-1的具体结构及其连接方式进行说明，其他驱动电路以及电流源的内部结构以及连接方式可以参照驱动电路42-1以及电流源44-1不再赘述。
驱动晶体管Q11的第一端耦合电流源44-1的第一端，驱动晶体管Q11的第二端通过电阻R11耦合至电流源44-1的第二端(即地GND)，驱动晶体管Q11的控制端耦合电流源44-1的控制端。运算放大器U11的正向输入端(+)耦合至控制电路43，运算放大器U11的反向输入端(-)耦合至驱动晶体管Q11的第二端。运算放大器U11的输出端耦合至开关K11的第一端，开关K11的第二端耦合至驱动晶体管Q11的控制端。
控制信号包括电压信号Vset(Vset11，Vset21，Vset31……Vsetn1)以及开关控制信号PWM(PWM11，PWM21，PWM31……PWMn1)；运算放大器U11的正向输入端(+)被配置为接收电压信号Vset11，开关K11的控制端被配置为接收开关控制信号PWM11；其中，当开关控制信号PWM11将开关导通时，电压信号Vset11用于控制流经驱动晶体管Q11的第一端和第二端的电流(即流经灯串Ls1的电路ILs1)，开关控制信号PWM11用于控制驱动晶体管Q11的第一端的电压(即灯串Ls1的通道电压VCH1)。其中，为了简化电路设计以及成本，结合图13所示，驱动晶体管Q11、Q21、Q31、……、Qn1均为N型晶体管。此时驱动晶体管Q11的第一端为d极，第二端为s极，控制端为g极。驱动晶体管Q11使用N型晶体管时，s极直接通过电阻R11连接地GND(为固定值)，只需将g极比s极电压高即可导通例如固定为Vin或Vout的电压即可导通，导通时电流由d极流向s极；电路设计较为简单。在采用其他方式时，例如驱动晶体管Q11、Q21、Q31、……、Qn1均为P型晶体管，则需要将驱动晶体管Q11的d极通过R11连接地，导通时电流自s极流向d极，而s极的电压不固定(取决于背光灯串的分压)，无法确定控制驱动晶体管Q11导通的g极电压，需单独设计隔离电源控制或自举升压电路。
具体的，结合图13对驱动电路42-1以及电流源44-1的具体功能说明如下：由于运算放大器U11的反向输入端(-)连接晶体管Q11直接连接Q11的s极，这样当开关K11将U11的输出端与Q11的g极导通时，形成闭环反馈，则U11正向输入端(+)输入的电压信号Vset11与Q11的s极的电压相等；由此可以构建如下公式：
Vout＝VLs1+VCH1，式一；其中，VLS1为背光灯串Ls1的分压，VCH1为Q11的d极的电压；
VLs1＝VF1+VF2+VF3+……VFm，式二；m为背光灯串LS1上LED的数量，VF为LED的正向导通压降；
ILs1＝Vset11/R11，式三；ILs1为背光灯串Ls1的电流；
Vset11＝VCH1×DPWM11，式四；DPWM11为开关控制信号PWM11的占空比；
I＝I0exp(qVF/nkT-1)，式五；q、n、k和T为常数，I0为LED的反向饱和电流；
这样基于上述式一至式五，则当VCH1较高时，则可以调节增大Vset11，则由式三可以得出这将导致ILs1增大。同时，根据式五，当ILs1增大后，导致VF变大。从而由式二可以得到VLs1将变大。结合式一，由于Vout固定，因此需要调小VCH1。根据式四，由于Vset11增大并且VCH1调小，为了使得式四平衡，因此需要提高DPWM11。这样便实现了增大或保持电流背光灯串的电流ILs1确保其正常发光的同时，降低了VCH1，因此也降低了背光驱动电路整体的损耗。当然，在一些示例中，当VCH1较小时，如果有需要提高VCH1，也可以调节减小Vset11，并降低DPWM11。
当然，在上述说明是主要是以控制电路43检测VCH1为例进行说明，通常Q11的g极电压与d极电压的关系是固定的；因此，由于Q11的g极电压反映了d极电压，因此也可以将g极电压作为上述的电学信号，及当g极电压大于阈值(其中可以理解的是对g极和d极设置的阈值并不相同)时，刚好反映了VCH1较高。
进一步的，结合图14所示，开关K11包括：晶体管Q12和晶体管Q13；晶体管Q12的第一端耦合于地GND，晶体管Q12的第二端耦合于晶体管Q13的控制端，晶体管Q12的控制端耦合于控制电路43；晶体管Q13的第一端耦合于运算放大器U11的输出端，晶体管Q13的第二端耦合于驱动晶体管Q11的控制端，晶体管Q13的控制端还通过电阻R12耦合于运算放大器U11的输出端；晶体管Q12，被配置为在开关控制信号Vset11的控制下周期性的将晶体管Q12的第一端和第二端导通；晶体管Q13，被配置为在晶体管Q12的第一端与第二端导通时，将晶体管Q13的第一端与第二端导通，以将运算放大器U11的输出端的信号传输至驱动晶体管Q11的控制端。
示例性的，晶体管Q12可以为N型晶体管，Q13可以为P型晶体管，其中晶体管Q12为N型晶体管时，s极作为第一端，d极作为第二端，g极作为控制端；晶体管Q13可为P型晶体管时，s极作为第一端，d极作为第二端，g极作为控制端；这样，由于Q12导通时，电流由d极流向s极，Q13导通时电流由s极流向d极，并且Q12的s极连接地GND为固定电压，便于电路设计，并且Q12导通时，电阻R12给Q13的s极和g极提供了固定的压差，只要s极的电压大于g极，并满足导通的阈值条件即可实现Q13的导通。
结合图15所示，背光驱动电路还包括：带隙性基准源45(45-1、45-2、45-3、……、45-n)。如图15所示，带隙性基准源45-1连接于驱动电路42-1与控制电路43之间；带隙性基准源45-2连接于驱动电路42-2与控制电路43之间；带隙性基准源45-3连接于驱动电路42-3与控制电路43之间；带隙性基准源45-n连接于驱动电路42-n与控制电路43之间。带隙性基准源45(45-1、45-2、45-3、……、45-n)，被配置为按照预定比例调整电压信号Vset(Vset11、Vset21、Vset31、……、Vsetn1)。当然图15中示出的控制电路43是检测电流源44的第一端的电学信号；如图16所示，该带隙性基准源45也可以应用于控制电路43是检测电流源44的控制端的电学信号的方案。
如图17所示，提供了一种带隙性基准源45的具体结构示意图，包括：晶体管Q14、Q15、Q16以及运算放大器U13、电阻R13和R14；其中，Q15的第一端连接电源端VCC， Q16的第一端连接电源端VCC；Q15的控制端连接Q16的控制端，Q15的第二端连接Q15的控制端以及Q14的第一端，Q14的第二端通过电阻R13连接地GND；运算放大器的正向输入端(+)连接控制电路43，用于接收电压信号Vset11；运算放大器U13的反向输入端(-)连接地GND；Q16的第二端通过电阻R14连接驱动电路42-1(具体的连接驱动电路42-1的运算放大器U11的正向输入端(+))。这样，带隙性基准源45能够按照电阻R13和R14的比例关系调整Vset11与输出至驱动电路42-1的电压的比例；这样当控制电路43对Vset11的控制步长较大(例如50mV)时，可以通过调整电阻R13和R14的比例关系，将输出至运算放大器U11的正向输入端(+)的电压信号调整至更小的步长(例如10mv)，这样，根据上述式三，在控制背光灯串Ls1的电流时，可以实现更小的电流精度，从而可以实现更精确的背光亮度调整。此外，为了降低电路设计的复杂度以及成本，Q15以及Q16可以采用P型晶体管，Q14可以采用N型晶体管，晶体管Q14为N型晶体管时，s极作为第二端，d极作为第一端，g极作为控制端；晶体管Q15、Q16为P型晶体管时，s极作为第一端，d极作为第二端，g极作为控制端。
当然，在一些场景下，背光模组的每个子灯板需要提供16、32、48甚至更多通道的背光灯串。受限于控制电路43提供的端口数量的限制当控制电路43不能提供对应通道数量的端口以实现上述的电流源44的第一端或控制端的电学信号的检测时，如图18所示，本申请的实施例提供的背光驱动电路还包括：选择器46，其中选择器46包括多个输入端、一个输出端以及至少一个控制端，各个电流源44(44-1、44-2、44-3、……、44-n)的第一端或电流源的控制端耦合至选择器46的输入端，选择器46的输出端耦合至控制电路43，选择器46的至少一个控制端耦合至控制电路43；控制电路43，被配置为通过选择器46的至少一个控制端向选择器46输出选通控制信号；选择器46，被配置为根据选通控制信号将选择器46的任一输入端与选择器46的输出端导通。
例如：当子灯板包含4个通道的背光灯串(Ls1、Ls2、Ls3以及Ls4)时，则选择器46可以包括四个输入端，以及两个控制端。这样，控制电路43可以向两个控制端输入两位二进制码实现对选择器46的选通控制。例如，控制电路43通过两个控制端向选择器46输入二进制码00,则选择器46将第一个输入端与输出端导通，如此将背光灯串Ls1连接的电流源44-1的第一端与控制电路43导通，实现对电流源44-1的第一端的电学信号的检测；控制电路43通过两个控制端向选择器46输入二进制码01,则选择器46将第二个输入端与输出端导通，如此将背光灯串Ls2连接的电流源44-2的第一端与控制电路43导通，实现对电流源44-2的第一端的电学信号的检测；控制电路43通过两个控制端向选择器46输入二进制码10,则选择器46将第三个输入端与输出端导通，如此将背光灯串Ls3连接的电流源44-3的第一端与控制电路43导通，实现对电流源44-3的第一端的电学信号的检测；控制电路43通过两个控制端向选择器46输入二进制码11,则选择器46将第四个输入端与输出端导通，如此将背光灯串Ls4连接的电流源44-4的第一端与控制电路43导通，实现对电流源44-4的第一端的电学信号的检测。如此，分时对各个电流源44的第一端的电学信号进行检测，降低了控制电路43的复杂度。当然，图18中示出的控制电路43是检测电流源44的第一端的电学信号；如图19所示，该选择器46也可以应用于控制电路43检测电流源44的控制 端的电学信号的方案。
在上述方案中，控制电路43主要是在模拟域对电流源44的第一端或控制端的信号进行检测，即直接检测电流源44的第一端或控制端的模拟信号。
在一些方案中，控制电路43还可以在数字域实现对电流源44的第一端或控制端的信号进行检测。参照图20所示，该背光驱动电路还包括：至少一个比较器(U12、U22、U32、……、Un2)以及参考电压生成电路47。以比较器U12的连接关系为例，U12的正向输入端耦合于电流源44-1的第一端或者电流源44-1的控制端，比较器U12的反向输入端耦合参考电压生成电路47；比较器U12的输出端耦合控制电路43；参考电压生成电路47，被配置为生成第一参考电压Vref；比较器U12，被配置为将电流源44-1的第一端的电压与第一参考电压Vref进行比较，或者将电流源44-1的控制端电压与所述第一参考电压Vref进行比较，在比较器U12的输出端输出比较结果。例如，当电流源44-1的第一端的电压大于第一参考电压Vref，或者电流源44-1的控制端的电压大于第一参考电压Vref，则输出比较结果1，否则输出比较结果0；控制电路43，被配置为根据比较结果确定电流源44-1的第一端或者电流源44-1的控制端的电学信号。其中，其他比较器U22、U32、……、Un2分别与对应的电流源44-2、44-3、……、44-n的连接关系以及功能与上述U12类似，不在赘述。这样，当第一参考电压Vref以一定步长逐步升高时，则最先小于第一参考电压Vref的电流源44-x连接的比较器Ux1将输出0，其他电流源44连接的比较器输出为1；此时，控制电路43可以控制参考电压生成电路47保持该第一参考电压Vref，通过调整其他电流源44连接的驱动电路的Vset以及PDM，以调整其他电流源44的第一端或控制端的电压，直至所有比较器输出0，则各个电流源44的第一端的电压(或控制端的电压)被调整至较低的接近或相同水平。当然，以上是以某个电流源44的第一端的电压(或控制端的电压)为基准调整其他电流源44的第一端的电压(或控制端的电压)；当然，为了使得所有电流源44的第一端的电压(或控制端的电压)达到稳定在指定电压，也可以将第一参考电压Vref配置为该指定电压。当然图20中示出的控制电路43是检测电流源44的第一端的电学信号；如图21所示，控制电路43在数字域实现对电流源44的第一端或控制端的信号进行检测也可以应用于控制电路43是检测电流源44的控制端的电学信号的方案。
此外，结合图22所示，提供一种第一芯片CS1，应用于背光模组，背光模组的灯板上设置有至少一条背光灯串,背光灯串包括至少一个串联的发光单元；其中该第一芯片CS1，包括：上述的至少一个驱动电路42以及至少一个电流源44；结合图10以及图11的连接方式，电流源44的第一端，用于耦合背光灯串Ls的阴极，背光灯串Ls的阳极耦合于电源41；电流源44的第二端，用于耦合于地GND；驱动电路42，耦合于电流源44的控制端；驱动电路42还耦合于控制电路43；电流源44的第一端或者电流源44的控制端，还用于耦合于控制电路43；其中，驱动电路42、控制电路43以及电流源44的功能可以参照上述示例不再赘述。具体的，参照图22提供的该第一芯片CS1的封装结构，还包括输入引脚(Pin-Pinx)、输出引脚(pout1-poutn)。其中在图22所示的示例中，还提供了第二芯片CS2，其中第二芯片CS2包括上述的控制电路43，其中控制电路43的功能以及连接方式参照上述图10以及图11的描述，此 处不再赘述。具体的，参照图22提供的该第二芯片CS2的封装结构，还包括输入引脚(Pin-Pinn)、输出引脚(pout1-poutm)，其中m＝2n。其中，第一芯片CS1的输入引脚(Pin-Pinm)与第二芯片CS2的输出引脚(pout1-poutm)一一连接，提供了控制电路43与各个驱动电路42的连接；第一芯片CS1的输出引脚(pout1-poutn)分别连接一条背光灯串Ls(Ls1-Lsn)的阴极，第二芯片CS2的输入引脚(Pin-Pinn)分别连接一条背光灯串的阴极Ls(Ls1-Lsn)。这样，实现了对各个电流源的第一端的电学信号的检测方案。
在图23提供的方案中，相对于图22所示，为了实现对各个电流源的控制端的电学信号的检测方案。第一芯片CS1还包括外接引脚(pg1-pgn)，其中每个外接引脚(pg1-pgn)连接一个电流源的控制端(即驱动晶体管的g极)，在图23提供的方案中第二芯片CS2的输入引脚(Pin-Pinn)分别与第一芯片CS1的外接引脚(pg1-pgn)一一连接，从而实现了对各个电流源的控制端的电学信号的检测方案。此外，当背光驱动电路还包括上述的间隙基准源45、选择器46、比较器(U12、U22、……、Un2)以及参考电压生成电路47中的一个或多个部件时，也可以将其选择性的集成于第一芯片CS1或第二芯片CS2。例如，可以将间隙基准源45集成于第一芯片CS1，将选择器46、比较器(U12、U22、……、Un2)以及参考电压生成电路47集成于第二芯片CS2。
在图24提供的方案中，还可以将第二芯片CS2集成于第一芯片CS1，这样，第一芯片CS1包括了上述的背光驱动电路中的至少一个驱动电路42、控制电路43以及至少一个电流源44。其中，驱动电路42、控制电路43以及电流源44的功能可以参照上述示例不再赘述。具体的，参照图24提供的该第一芯片CS1的封装结构，包括引脚(Pi/o1-Pi/on)，其中每个引脚(Pi/o1-Pi/on)连接一个灯串的阴极，以提供背光驱动电路与各个背光灯串的连接。此外，当背光驱动电路还包括上述的间隙基准源45、选择器46、比较器(U12、U22、……、Un2)以及参考电压生成电路47中的一个或多个部件时，也可以将其选择性的集成于第一芯片CS1。
尽管在此结合各实施例对本申请进行了描述，然而，在实施所要求保护的本申请过程中，本领域技术人员通过查看附图、公开内容、以及所附权利要求书，可理解并实现所公开实施例的其它变化。在权利要求中，“包括”一词不排除其他组成部分或步骤，“一”或“一个”不排除多个的情况。相互不同的从属权利要求中记载了某些措施，但这并不表示这些措施不能组合起来产生良好的效果。
以上已经描述了本申请的各实施例，上述说明是示例性的，并非穷尽性的，并且也不限于所披露的各实施例。在不偏离所说明的各实施例的范围和精神的情况下，对于本技术领域的普通技术人员来说许多修改和变更都是显而易见的。本文中所用术语的选择，旨在最好地解释各实施例的原理、实际应用或对市场中的技术的改进，或者使本技术领域的其它普通技术人员能理解本文披露的各实施例。

Claims (21)

  1. 一种背光驱动电路，应用于背光模组，所述背光模组的灯板上设置有至少一条背光灯串,所述背光灯串包括至少一个串联的发光单元；其特征在于，所述背光驱动电路包括：控制电路、至少一个驱动电路以及至少一个电流源；
    所述电流源的第一端用于耦合于所述背光灯串的阴极，所述背光灯串的阳极用于耦合于电源；所述电流源的第二端用于耦合于地；所述驱动电路耦合于所述电流源的控制端；所述控制电路耦合于所述驱动电路，所述控制电路还耦合于所述电流源的第一端或者所述电流源的控制端；
    所述控制电路，被配置为检测所述电流源的第一端或者所述电流源的控制端的电学信号；
    所述控制电路，还被配置为根据所述电学信号向所述驱动电路输出控制信号；
    所述驱动电路，被配置为根据所述控制信号调整所述电流源的第一端与第二端流经的电流，以及所述电流源的第一端的电压。
  2. 根据权利要求1所述的背光驱动电路，其特征在于，所述驱动电路包括运算放大器以及第一开关；所述电流源包括驱动晶体管以及第一电阻；
    所述驱动晶体管的第一端耦合所述电流源的第一端，所述驱动晶体管的第二端通过所述第一电阻耦合至所述电流源的第二端，所述驱动晶体管的控制端耦合所述电流源的控制端；
    所述运算放大器的正向输入端耦合至所述控制电路，所述运算放大器的反向输入端耦合至所述驱动晶体管的第二端；
    所述运算放大器的输出端耦合至所述第一开关的第一端，所述第一开关的第二端耦合至所述驱动晶体管的控制端；
    所述控制信号包括电压信号以及开关控制信号；
    所述运算放大器的正向输入端被配置为接收所述电压信号，所述第一开关的控制端被配置为接收所述开关控制信号；
    其中，当所述开关控制信号将所述第一开关导通时，所述电压信号用于控制流经所述驱动晶体管的第一端和第二端的电流，所述开关控制信号用于控制所述驱动晶体管的第一端的电压。
  3. 根据权利要求1或2所述的背光驱动电路，其特征在于，
    若所述控制电路确定所述电学信号对应的电压大于第一阈值，所述控制电路通过所述控制信号控制所述驱动电路提高所述电流源的第一端与第二端流经的电流，并降低所述电流源的第一端的电压。
  4. 根据权利要求1或2所述的背光驱动电路，其特征在于，
    若所述控制电路确定所述电学信号对应的电压小于第二阈值，所述控制电路通过所述控制信号控制所述驱动电路降低所述电流源的第一端与第二端流经的电流，并提高所述电流源的第一端的电压。
  5. 根据权利要求1-4任一项所述的背光驱动电路，其特征在于，还包括：带隙性基准源，所述带隙性基准源连接于所述驱动电路与所述控制电路之间；
    所述带隙性基准源，被配置为按照预定比例调整所述电压信号。
  6. 根据权利要求2所述的背光驱动电路，其特征在于，所述第一开关包括：第一晶体管和第二晶体管；
    所述第一晶体管的第一端耦合于地，所述第一晶体管的第二端耦合于所述第二晶体管的控制端，所述第一晶体管的控制端耦合于所述控制电路；
    所述第二晶体管的第一端耦合于所述运算放大器的输出端，所述第二晶体管的第二端耦合于所述驱动晶体管的控制端，所述第二晶体管的控制端还通过第二电阻耦合于所述运算放大器的输出端；
    所述第一晶体管，被配置为在所述开关控制信号的控制下周期性的将所述第一晶体管的第一端和所述第一晶体管的第二端导通；
    所述第二晶体管，被配置为在所述第一晶体管的第一端与所述第一晶体管的第二端导通时，将所述第二晶体管的第一端与所述第二晶体管的第二端导通，以将所述运算放大器的输出端的信号传输至所述驱动晶体管的控制端。
  7. 根据权利要求6所述的背光驱动电路，其特征在于，所述第一晶体管包括N型晶体管，所述第二晶体管包括P型晶体管；所述第一晶体管的第一端为所述N型晶体管的源极；所述第一晶体管的第二端为所述N型晶体管的漏极，所述第一晶体管的控制端为所述N型晶体管的栅极；所述第二晶体管的第一端为所述P型晶体管的源极；所述第二晶体管的第二端为所述P型晶体管的漏极，所述第二晶体管的控制端为所述P型晶体管的栅极。
  8. 根据权利要求1-7任一项所述的背光驱动电路，其特征在于，还包括：至少一个比较器以及参考电压生成电路；
    所述比较器的正向输入端耦合于所述电流源的第一端或者所述电流源的控制端，所述比较器的反向输入端耦合所述参考电压生成电路；所述比较器的输出端耦合所述控制电路；
    所述参考电压生成电路，被配置为生成第一参考电压；
    所述比较器，被配置为将所述电流源的第一端的电压与所述第一参考电压进行比较，或者将所述电流源的控制端电压与所述第一参考电压进行比较，在所述比较器的输出端输出比较结果；
    所述控制电路，被配置为根据所述比较结果确定所述电流源的第一端或者所述电流源的控制端的电学信号。
  9. 根据权利要求1-8任一项所述的背光驱动电路，其特征在于，还包括：选择器，其中所述选择器包括多个输入端、一个输出端以及至少一个控制端，所述电流源的第一端或所述电流源的控制端耦合至所述选择器的输入端，所述选择器的输出端耦合至所述控制电路，所述选择器的至少一个控制端耦合至所述控制电路；
    所述控制电路，被配置为通过所述选择器的至少一个控制端向所述选择器输出选通控制信号；
    所述选择器，被配置为根据所述选通控制信号将所述选择器的任一输入端与所述选择器的输出端导通。
  10. 一种芯片，应用于背光模组，所述背光模组的灯板上设置有至少一条背光灯串,所述背光灯串包括至少一个串联的发光单元；其特征在于，所述芯片包括：至少一个 驱动电路以及至少一个电流源；
    所述电流源的第一端，用于耦合于所述背光灯串的阴极，所述背光灯串的阳极耦合于电源；所述电流源的第二端，用于耦合于地；所述驱动电路，耦合于所述电流源的控制端；所述驱动电路还用于耦合于所述控制电路；所述电流源的第一端或者所述电流源的控制端，还用于耦合于所述控制电路；
    所述控制电路，被配置为检测所述电流源的第一端或者所述电流源的控制端的电学信号；
    所述控制电路，还被配置为根据所述电学信号向所述驱动电路输出控制信号；
    所述驱动电路，被配置为根据所述控制信号调整所述电流源的第一端与第二端流经的电流，以及所述电流源的第一端的电压。
  11. 根据权利要求10所述的芯片，其特征在于，所述驱动电路包括运算放大器以及第一开关；所述电流源包括驱动晶体管以及第一电阻；
    所述驱动晶体管的第一端耦合所述电流源的第一端，所述驱动晶体管的第二端通过所述第一电阻耦合至所述电流源的第二端，所述驱动晶体管的控制端耦合所述电流源的控制端；
    所述运算放大器的正向输入端耦合至所述控制电路，所述运算放大器的反向输入端耦合至所述驱动晶体管的第二端；
    所述运算放大器的输出端耦合至所述第一开关的第一端，所述第一开关的第二端耦合至所述驱动晶体管的控制端；
    所述控制信号包括电压信号以及开关控制信号；
    所述运算放大器的正向输入端被配置为接收所述电压信号，所述第一开关的控制端被配置为接收所述开关控制信号；
    其中，所述当所述开关控制信号将所述第一开关导通时，所述电压信号用于控制流经所述驱动晶体管的第一端和第二端的电流，所述开关控制信号用于控制所述驱动晶体管的第一端的电压。
  12. 根据权利要求10或11所述的芯片，其特征在于，
    若所述控制电路确定所述电学信号对应的电压大于第一阈值，所述控制电路通过所述控制信号控制所述驱动电路提高所述电流源的第一端与第二端流经的电流，并降低所述电流源的第一端的电压。
  13. 根据权利要求10或11所述的芯片，其特征在于，
    若所述控制电路确定所述电学信号对应的电压小于第二阈值，所述控制电路通过所述控制信号控制所述驱动电路降低所述电流源的第一端与第二端流经的电流，并提高所述电流源的第一端的电压。
  14. 根据权利要求10-13任一项所述的芯片，其特征在于，还包括：带隙性基准源，所述带隙性基准源连接于所述运算放大器的正向输入端与所述控制电路之间；
    所述带隙性基准源，被配置为按照预定比例调整所述电压信号。
  15. 根据权利要求11所述的芯片，其特征在于，所述第一开关包括：第一晶体管和第二晶体管；
    所述第一晶体管的第一端耦合于地，所述第一晶体管的第二端耦合于所述第二晶 体管的控制端，所述第一晶体管的控制端耦合于所述控制电路；
    所述第二晶体管的第一端耦合于所述运算放大器的输出端，所述第二晶体管的第二端耦合于所述驱动晶体管的控制端，所述第二晶体管的控制端还通过第二电阻耦合于所述运算放大器的输出端；
    所述第一晶体管，被配置为在所述开关控制信号的控制下周期性的将所述第一晶体管的第一端和所述第一晶体管的第二端导通；
    所述第二晶体管，被配置为在所述第一晶体管的第一端与所述第一晶体管的第二端导通时，将所述第二晶体管的第一端与所述第二晶体管的第二端导通，以将所述运算放大器的输出端的信号传输至所述驱动晶体管的控制端。
  16. 根据权利要求15所述的芯片，其特征在于，所述第一晶体管包括N型晶体管，所述第二晶体管包括P型晶体管；所述第一晶体管的第一端为所述N型晶体管的源极；所述第一晶体管的第二端为所述N型晶体管的漏极，所述第一晶体管的控制端为所述N型晶体管的栅极；所述第二晶体管的第一端为所述P型晶体管的源极；所述第二晶体管的第二端为所述P型晶体管的漏极，所述第二晶体管的控制端为所述P型晶体管的栅极。
  17. 根据权利要求10-16任一项所述的芯片，其特征在于，还包括：至少一个比较器以及参考电压生成电路；
    所述比较器的正向输入端耦合于所述电流源的第一端或者所述电流源的控制端，所述比较器的反向输入端耦合所述参考电压生成电路；所述比较器的输出端耦合所述控制电路；
    所述参考电压生成电路，被配置为生成第一参考电压；
    所述比较器，被配置为将所述电流源的第一端的电压与所述第一参考电压进行比较，或者将所述电流源的控制端电压与所述第一参考电压进行比较，在所述比较器的输出端输出比较结果；
    所述控制电路，被配置为根据所述比较结果确定所述电流源的第一端或者所述电流源的控制端的电学信号。
  18. 根据权利要求10-17任一项所述的芯片，其特征在于，还包括：选择器，其中所述选择器包括多个输入端、一个输出端以及至少一个控制端，所述电流源的第一端或所述电流源的控制端耦合至所述选择器的输入端，所述选择器的输出端耦合至所述控制电路，所述选择器的至少一个控制端耦合至所述控制电路；
    所述控制电路，被配置为通过所述选择器的至少一个控制端向所述选择器输出选通控制信号；
    所述选择器，被配置为根据所述选通控制信号将所述选择器的任一输入端与所述选择器的输出端导通。
  19. 根据权利要求10-18任一项所述的芯片，其特征在于，所述控制电路包含于所述芯片中。
  20. 一种背光模组，其特征在于，所述背光模组包括背板、平整板、灯板、扩散板；其中，所述平整板位于所述背板和所述灯板之间，所述灯板位于所述平整板与所述扩散板之间；所述灯板上设置有至少一条背光灯串，所述背板上设置有如权利要求1-9 任一项所述的背光驱动电路，或如权利要求10-19任一项所述的芯片。
  21. 一种电子设备，其特征在于，包括如权利要求20所述的背光模组，以及设置于所述背光模组的液晶面板。
PCT/CN2023/078144 2022-03-04 2023-02-24 背光驱动电路、芯片、背光模组及电子设备 WO2023165424A1 (zh)

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