CN112382241A - Backlight driving circuit, backlight driving control method and display device - Google Patents
Backlight driving circuit, backlight driving control method and display device Download PDFInfo
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- 125000004122 cyclic group Chemical group 0.000 claims abstract description 6
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- 239000004973 liquid crystal related substance Substances 0.000 description 3
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/3406—Control of illumination source
- G09G3/3413—Details of control of colour illumination sources
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/06—Adjustment of display parameters
- G09G2320/0626—Adjustment of display parameters for control of overall brightness
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Abstract
The application discloses backlight drive circuit, backlight drive control method and display device, this backlight drive circuit includes: a backlight driver for providing a driving voltage; the controller comprises a plurality of control units arranged in an array, the control units receive driving voltage respectively, the control units are arranged corresponding to the light bars, each control unit comprises an enabling end and a driving end, the enabling ends receive enabling signals, the driving ends receive dimming control signals, when the enabling signals are effective, the dimming control signals are processed through cyclic shift to obtain first control signals, when the first control signals are effective, the driving signals are provided for the light bars corresponding to the control units, when the enabling signals are ineffective, the dimming control signals serve as second control signals, and when the second control signals are effective, the driving signals are provided for the light bars corresponding to the control units. The backlight driving circuit reduces the manufacturing cost of the backlight system and improves the maximum brightness of the backlight source.
Description
Technical Field
The present invention relates to the field of display technologies, and in particular, to a backlight driving circuit, a backlight driving control method, and a display device.
Background
In the liquid crystal display device, the backlight technology directly affects the power consumption and display quality of the liquid crystal display. Because a Light Emitting Diode (LED) is a semiconductor device with sensitive characteristics, the LED has the characteristics of high light emitting efficiency, small size, low power consumption, long service life, safety, reliability, environmental protection, energy saving, and the like, and is gradually applied to a backlight of a liquid crystal display device.
In the related art, the backlight source is a direct type backlight, and a backlight driving circuit is used to provide a driving voltage for the backlight source. The backlight is disposed opposite to the entire display area of the display panel. In order to improve the image display effect, the backlight aspect is generally changed, the light bars of the backlight source have different design modes, and the light bars of the different design modes need different backlight driving circuits to drive. When the number of the LED light bars in the backlight source is large, a large number of backlight driving circuits need to be arranged for the backlight source, and the large number of backlight driving circuits excessively occupy the layout space of the printed circuit board, so that the manufacturing cost of the backlight system is increased. In order to reduce the number of backlight driving circuits, a plurality of light bars in different design modes are driven by the same backlight driving circuit, and the light bars are controlled to be sequentially opened in a scanning opening mode. And the plurality of light bars are sequentially turned on, so that the lighting time of each light bar is reduced, and the maximum brightness of the backlight source is reduced.
Therefore, it is desirable to design a backlight driving circuit, a backlight driving control method, and a display device to reduce the manufacturing cost of the backlight system and to improve the maximum luminance of the backlight.
Disclosure of Invention
The invention provides a backlight driving circuit, a backlight driving control method and a display device aiming at the problems in the prior art, so that the manufacturing cost of a backlight system is reduced, and the maximum brightness of a backlight source is improved.
According to an aspect of an embodiment of the present invention, there is provided a backlight driving circuit including:
a backlight driver for providing a driving voltage;
the controller comprises a plurality of control units which are arranged in an array, the control units respectively receive the driving voltage, the control units are arranged corresponding to the light bars, each control unit comprises an enabling end and a driving end, the enabling end receives an enabling signal, the driving end receives a dimming control signal, when the enabling signal is effective, the dimming control signal is processed through cyclic shift to obtain a first control signal, and when the first control signal is effective, the driving signal is provided for the light bar corresponding to the control unit,
and when the enable signal is invalid, the dimming control signal is used as a second control signal, and when the second control signal is valid, the driving signal is provided for the lamp strip corresponding to the control unit.
Optionally, the enable terminals of the control units in the same row are all connected to the same enable signal, and the drive terminals of the control units in the same column are all connected to the same dimming control signal.
Optionally, each of the control units comprises: the circuit comprises a first transistor, a second transistor, a shift register, a current source and a third resistor;
a first end of the third resistor receives the dimming control signal, a second end of the third resistor is connected with the input end of the shift register, a control end of the first transistor receives the enable signal, a first path end is connected with a connection node between the second end of the third resistor and the input end of the shift register, a second path end is connected with the output end of the shift register,
the control end of the second transistor is connected with a connection node between the second path end of the first transistor and the output end of the shift register, the second path end receives the driving voltage, the first path end is connected with the first end of the current source, and the second end of the current source provides the driving signal.
Optionally, the plurality of control units include a plurality of columns of control units, driving terminals of the plurality of columns of control units are respectively connected to the plurality of dimming control signals, and duty ratios of at least two dimming control signals in the plurality of dimming control signals are different.
Optionally, the plurality of control units comprise a plurality of rows of control units, the enable terminals of the plurality of rows of control units are respectively connected to a plurality of enable signals, and the plurality of enable signals are active row by row.
According to a second aspect of embodiments of the present invention, there is provided a display device including:
the backlight driving circuit of any one of the above.
According to a third aspect of the embodiments of the present invention, there is provided a backlight driving control method for a backlight driving circuit, where the backlight driving circuit includes a backlight driver and a controller, the controller includes a plurality of control units arranged in an array, the plurality of control units are disposed corresponding to a plurality of light bars, each control unit includes an enable terminal and a driving terminal, the enable terminal receives an enable signal, and the driving terminal receives a dimming control signal, the backlight driving control method includes:
providing a driving voltage by using the backlight driver;
for each control unit, receiving the driving voltage, when the enable signal is valid, circularly shifting and processing the dimming control signal to obtain a first control signal, when the first control signal is valid, providing the driving signal to the light bar corresponding to the control unit,
and when the enable signal is invalid, the dimming control signal is used as a second control signal, and when the second control signal is valid, the driving signal is provided for the lamp strip corresponding to the control unit.
Optionally, the enable terminals of the control units in the same row are all connected to the same enable signal, and the drive terminals of the control units in the same column are all connected to the same dimming control signal.
Optionally, the plurality of control units include a plurality of columns of control units, driving terminals of the plurality of columns of control units are respectively connected to the plurality of dimming control signals, and the backlight driving control method includes:
different duty cycles are set for at least two of the plurality of dimming control signals.
Optionally, the plurality of control units include a plurality of rows of control units, enable terminals of the plurality of rows of control units are respectively connected to a plurality of enable signals, and the backlight driving control method includes:
and providing effective enabling signals to the enabling ends of the multi-row control units row by row.
According to the backlight driving circuit, the backlight driving control method and the display device provided by the embodiment of the invention, the backlight driving circuit comprises a backlight driver and a controller, wherein the backlight driver is used for providing driving voltage; the controller comprises a plurality of control units which are arranged in an array, the control units receive driving voltage respectively, and the control units are arranged corresponding to the light bars. The control unit comprises an enabling end and a driving end, the enabling end receives an enabling signal, the driving end receives a dimming control signal, when the enabling signal is effective, the dimming control signal is processed through cyclic shift to obtain a first control signal, when the first control signal is effective, the driving signal is provided for a lamp bar corresponding to the control unit, when the enabling signal is ineffective, the dimming control signal serves as a second control signal, and when the second control signal is effective, the driving signal is provided for the lamp bar corresponding to the control unit. The starting time of the light bar corresponding to each control unit can be controlled by setting different duty ratios for the dimming control signal, so that the brightness of the corresponding light bar is adjusted, and an independent backlight driving circuit is prevented from being arranged for each light bar, so that the manufacturing cost of the backlight system is reduced.
The control unit includes: the circuit comprises a first transistor, a second transistor, a shift register, a current source and a third resistor. The first end of the third resistor receives the dimming control signal, the second end of the third resistor is connected with the input end of the shift register, the control end of the first transistor receives the enable signal, the first path end is connected with the connection node of the second end of the third resistor and the input end of the shift register, and the second path end is connected with the output end of the shift register. The control end of the second transistor is connected with the connection node of the second path end of the first transistor and the output end of the shift register, the second path end of the second transistor receives the driving voltage, the first path end of the second transistor is connected with the input end of the current source, and the output end of the current source provides the driving signal. The third resistor isolates the input end of the shift register from the input dimming control signal, and the shift register is prevented from being short-circuited with the corresponding dimming control signal.
The plurality of control units comprise a plurality of columns of control units, the driving ends of the plurality of columns of control units are respectively connected to the plurality of dimming control signals, and the duty ratios of at least two dimming control signals in the plurality of dimming control signals are different. The starting time of the light bars corresponding to each row of control units can be controlled by setting different duty ratios for the dimming control signals, and then the brightness of the corresponding light bars is adjusted.
The plurality of control units include a plurality of rows of control units, enable terminals of the plurality of rows of control units are respectively connected to a plurality of enable signals, and the plurality of enable signals are asserted row by row. Through the validity of the control enabling signal, the light bar corresponding to each control unit can be continuously displayed. When the enable signals are simultaneously effective, the light bars corresponding to each row of control units can be simultaneously and continuously displayed, and therefore the maximum brightness of the backlight source is improved.
Drawings
The above and other object features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings.
Fig. 1 shows a schematic structural diagram of a backlight driving circuit according to an embodiment of the present invention.
Fig. 2 shows a schematic structural diagram of a backlight driver according to an embodiment of the present invention.
Fig. 3 shows a schematic structural diagram of a controller according to an embodiment of the present invention.
Fig. 4 is a flowchart illustrating a backlight driving control method according to an embodiment of the present invention.
Detailed Description
The invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by like reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale. In addition, certain well known components may not be shown.
Numerous specific details of the invention are set forth in the following description in order to provide a more thorough understanding of the invention. However, as will be understood by those skilled in the art, the present invention may be practiced without these specific details.
Fig. 1 shows a schematic structural diagram of a backlight driving circuit according to an embodiment of the present invention. As shown in fig. 1, the backlight driving circuit 1000 includes: a backlight driver 100 and a controller 200. The controller 200 includes control units arranged in an array, and the control units are disposed corresponding to the light bars (not shown). Each light bar comprises at least one LED. Different light bars can have different designs. Each control unit comprises an enabling end E and a driving end D, wherein the enabling end E receives an enabling signal SE, the driving end D receives a dimming control signal SD, and the dimming control signal SD is a pulse width modulation signal.
The backlight driver 100 is used to provide the driving voltage VLED. Fig. 2 shows a schematic structural diagram of a backlight driver according to an embodiment of the present invention. As shown in fig. 2, in the backlight driver 100, a dc input voltage Vin is input to an input terminal, and a driving voltage VLED is output to an output terminal. The controller 200 serves as a load of the backlight driver 100. The backlight driver 100 includes: the backlight driving circuit comprises an inductor L1, a diode D1, a backlight driving chip 110, a first capacitor C1, a second capacitor C2, a third capacitor C3, a first resistor R1 and a second resistor R2. The inductor L1 and the diode D1 are connected in series between the dc input voltage Vin and the driving voltage VLED, the anode of the diode D1 is connected to the inductor L1, and the cathode of the diode D1 provides the driving voltage VLED. The first capacitor C1 is connected between the dc input voltage Vin and a reference ground. The second capacitor C2 is connected between the driving voltage VLED and the reference ground potential. The backlight driving chip 110 has a main switching tube built therein and includes a plurality of pins connected to peripheral elements. An intermediate node of the inductor L1 and the diode D1 is connected to a SW pin of the backlight driving chip 110, and the SW pin is connected to the built-in main switch tube. The inductor L1, the diode D1 and the main switching tube in the backlight driving chip 110 form a boost power converter. The first resistor R1 and the third capacitor C3 are connected in series between the dc input voltage Vin and the ground reference, and the intermediate node between the first resistor R1 and the third capacitor C3 is connected to the Vbat pin of the backlight driver chip 110 to provide the battery voltage Vbat. The Vo pin of the backlight driving chip 110 is connected to the driving voltage VLED for monitoring the driving voltage VLED. The second resistor R2 is connected between the Iset pin, which is used to program the output current at the output of the backlight driver 100, and the reference ground potential. The power ground and the signal ground of the backlight driving chip 110 are grounded via a PGND pin and a GND pin, respectively, the EN pin receives an external enable signal, the Dctrl pin receives a pulse width modulation signal PWM, and the IFB pin receives a feedback current IFB of a plurality of light bars (not shown) provided corresponding to the plurality of control units 210. The voltage value of the driving voltage VLED can be controlled by controlling the duty ratio of the pulse width modulation signal PWM, so as to control the brightness of the plurality of light bars. The backlight driver chip 110 is, for example, an integrated circuit chip available from Texas instruments, USA, model number TPS 61181A.
The control units in the controller 200 respectively receive the driving voltages VLED. Each control unit is used for receiving an enable signal SE and a dimming control signal SD, when the enable signal SE is valid, the dimming control signal SD is processed by cyclic shift to obtain a first control signal T1n, where n is a natural number greater than 0, when the first control signal T1n is valid, the driving signal Vout is provided to a light bar corresponding to the control unit, and when the first control signal T1n is invalid, no signal is provided for the light bar corresponding to the control unit, that is, 0 level is provided to the light bar corresponding to the control unit; each control unit is further configured to use the dimming control signal SD as a second control signal T2m when the enable signal SE is inactive, where m is a natural number greater than 0, provide the driving signal Vout to the light bar corresponding to the control unit when the second control signal T2m is active, and provide no signal to the light bar corresponding to the control unit when the second control signal T2m is inactive, that is, provide a level of 0 to the light bar corresponding to the control unit. The signal length of the dimming control signal SD is finite, the signal length of the second control signal T2m is the same as the signal length of the dimming control signal SD, and the first control signal T1n is a periodic signal having the dimming control signal SD as one period.
Fig. 3 shows a schematic structural diagram of a controller according to an embodiment of the present invention. In the present embodiment, 6 control units are exemplified, but in other embodiments, the number of the control units may not be 6. As shown in fig. 3, the controller 200 includes: a first control unit 211, a second control unit 212, a third control unit 213, a fourth control unit 214, a fifth control unit 215, and a sixth control unit 216 arranged in an array. The first control unit 211 and the second control unit 212 are located in the same row, and the enable terminal E11 of the first control unit 211 and the enable terminal E12 of the second control unit 212 are connected to the same enable signal SE 1. The third control unit 213 and the fourth control unit 214 are located in the same row, and the enable terminal E21 of the third control unit 213 and the enable terminal E22 of the fourth control unit 214 are connected to the same enable signal SE 2. The fifth control unit 215 and the sixth control unit 216 are located in the same row, and the enable terminal E31 of the fifth control unit 215 and the enable terminal E32 of the sixth control unit 216 are connected to the same enable signal SE 3. The first, third and fifth control units 211, 213 and 215 are located at the same column, and the driving terminal D11 of the first control unit 211, the driving terminal D21 of the third control unit 213 and the driving terminal D31 of the fifth control unit 215 are connected to the same dimming control signal SD 1. The second, fourth and sixth control units 212, 214 and 216 are located in the same column, and the driving terminal D12 of the second control unit 212, the driving terminal D22 of the fourth control unit 214 and the driving terminal D32 of the sixth control unit 216 are connected to the same dimming control signal SD 2. It should be noted that the number of rows and columns of the control unit array in the embodiment of the present invention is only an example, and should not limit the embodiment of the present invention.
Further, each control unit includes: the circuit comprises a first transistor Mxya, a second transistor Mxyb, a shift register Uxy, a current source Ixy and a third resistor Rxy, wherein x and y are natural numbers larger than 0.
Specifically, the first control unit 211 includes: a first transistor M11a, a second transistor M11b, a shift register U11, a current source I11, and a third resistor R11. A first end of the third resistor R11 receives the dimming control signal SD1, a second end of the third resistor R11 is connected to the input end of the shift register U11, a control end of the first transistor M11a receives the enable signal SE1, a first path end is connected to a connection node between the second end of the third resistor R11 and the input end of the shift register U11, and a second path end is connected to the output end of the shift register U11. The control terminal of the second transistor M11b is connected to the connection node between the second path terminal of the first transistor M11a and the output terminal of the shift register U11, the second path terminal receives the driving voltage VLED, the first path terminal is connected to the input terminal of the current source I11, and the output terminal of the current source I11 provides the driving signal Vout.
The second control unit 212 includes: a first transistor M12a, a second transistor M12b, a shift register U12, a current source I12, and a third resistor R12. A first end of the third resistor R12 receives the dimming control signal SD2, a second end of the third resistor R12 is connected to the input end of the shift register U12, a control end of the first transistor M12a receives the enable signal SE1, a first path end is connected to a connection node between the second end of the third resistor R12 and the input end of the shift register U12, and a second path end is connected to the output end of the shift register U12. The control terminal of the second transistor M12b is connected to the connection node between the second path terminal of the first transistor M12a and the output terminal of the shift register U12, the second path terminal receives the driving voltage VLED, the first path terminal is connected to the input terminal of the current source I12, and the output terminal of the current source I12 provides the driving signal Vout.
The third control unit 213 includes: a first transistor M21a, a second transistor M21b, a shift register U21, a current source I21, and a third resistor R21. A first end of the third resistor R21 receives the dimming control signal SD1, a second end of the third resistor R21 is connected to the input end of the shift register U21, a control end of the first transistor M21a receives the enable signal SE2, a first path end is connected to a connection node between the second end of the third resistor R21 and the input end of the shift register U21, and a second path end is connected to the output end of the shift register U21. The control terminal of the second transistor M21b is connected to the connection node between the second path terminal of the first transistor M21a and the output terminal of the shift register U21, the second path terminal receives the driving voltage VLED, the first path terminal is connected to the input terminal of the current source I21, and the output terminal of the current source I21 provides the driving signal Vout.
The fourth control unit 214 includes: a first transistor M22a, a second transistor M22b, a shift register U22, a current source I22, and a third resistor R22. A first end of the third resistor R22 receives the dimming control signal SD2, a second end of the third resistor R22 is connected to the input end of the shift register U22, a control end of the first transistor M22a receives the enable signal SE2, a first path end is connected to a connection node between the second end of the third resistor R22 and the input end of the shift register U22, and a second path end is connected to the output end of the shift register U22. The control terminal of the second transistor M22b is connected to the connection node between the second path terminal of the first transistor M22a and the output terminal of the shift register U22, the second path terminal receives the driving voltage VLED, the first path terminal is connected to the input terminal of the current source I22, and the output terminal of the current source I22 provides the driving signal Vout.
The fifth control unit 215 includes: a first transistor M31a, a second transistor M31b, a shift register U31, a current source I31, and a third resistor R31. A first terminal of the third resistor R31 receives the dimming control signal SD1, and a second terminal of the third resistor R31 is connected to the input terminal of the shift register U31. A control terminal of the first transistor M31a receives the enable signal SE3, a first path terminal is connected to a connection node between the second terminal of the third resistor R31 and the input terminal of the shift register U31, and a second path terminal is connected to the output terminal of the shift register U31. The control terminal of the second transistor M31b is connected to the connection node between the second path terminal of the first transistor M31a and the output terminal of the shift register U31, the second path terminal receives the driving voltage VLED, the first path terminal is connected to the input terminal of the current source I31, and the output terminal of the current source I31 provides the driving signal Vout.
The sixth control unit 216 includes: a first transistor M32a, a second transistor M32b, a shift register U32, a current source I32, and a third resistor R32. A first terminal of the third resistor R32 receives the dimming control signal SD2, and a second terminal of the third resistor R32 is connected to the input terminal of the shift register U32. A control terminal of the first transistor M32a receives the enable signal SE3, a first path terminal is connected to a connection node between the second terminal of the third resistor R32 and the input terminal of the shift register U32, and a second path terminal is connected to the output terminal of the shift register U32. The control terminal of the second transistor M32b is connected to the connection node between the second path terminal of the first transistor M32a and the output terminal of the shift register U32, the second path terminal receives the driving voltage VLED, the first path terminal is connected to the input terminal of the current source I32, and the output terminal of the current source I32 provides the driving signal Vout.
The principle of the backlight driving circuit according to the embodiment of the present invention will be described in detail with reference to fig. 1 to 3 and specific embodiments.
Taking the first control unit 211 as an example, the first transistor M11a and the second transistor M11b are N-type thin film transistors. When the enable signal SE1 is asserted (the enable signal SE1 is at a high level), the first transistor M11a is turned on, i.e., the output terminal of the shift register U11 is connected to the input terminal, and the shift register U11 cyclically shifts the dimming control signal SD1 to obtain the first control signal T11. When the first control signal T11 is active (the first control signal T11 is at a high level), the second transistor M11b is turned on, the second terminal of the second transistor M11b receives the driving voltage VLED, the output terminal of the current source I11 provides the driving signal Vout to the light bar corresponding to the first control unit 211, and when the first control signal T11 is inactive (the first control signal T11 is at a low level), no signal is provided to the light bar corresponding to the first control unit 211, that is, a 0 level is provided to the light bar corresponding to the first control unit 211. When the enable signal SE1 is inactive (the enable signal SE1 is at a low level), the first transistor M11a is turned off, that is, the output terminal of the shift register U11 is disconnected from the input terminal, the dimming control signal SD1 is used as the second control signal T21, when the second control signal T21 is active (the second control signal T21 is at a high level), the second transistor M11b is turned on, the second terminal of the second transistor M11b receives the driving voltage VLED, the output terminal of the current source I11 provides the driving signal Vout to the light bar corresponding to the first control unit 211, and when the second control signal T21 is inactive (the second control signal T21 is at a low level), the driving signal is not provided to the light bar corresponding to the first control unit 211, that is, a 0 level is provided to the light bar corresponding to the first control unit 211. The current source I11 controls the current value of the driving signal Vout to realize the constant current driving signal provided to the LEDs in the light bar.
It should be noted that, since the first control signal T11 is a periodic signal with the dimming control signal SD1 as a period, when the enable signal SE1 is asserted, the first control signal T11 continuously controls the light bar corresponding to the first control unit 211 to be turned on or off, and since the frequency of the first control signal T11 is higher, the turn-off time of the corresponding light bar is shorter, which is equivalent to making the corresponding light bar continuously display. The first control unit 211, the second control unit 212, the third control unit 213, the fourth control unit 214, the fifth control unit 215 and the sixth control unit 216 shown in fig. 3 operate on the same principle. By controlling the validity of the enable signal SE1, the enable signal SE2 and the enable signal SE3, the light bar corresponding to each control unit 210 can be continuously displayed. When the control enable signal SE1, the enable signal SE2, and the enable signal SE3 are simultaneously asserted, the light bars corresponding to each row of the control units 210 can be continuously displayed at the same time, so that the maximum brightness of the backlight source is improved. The starting time of the light bar corresponding to each row of the control unit 210 can be controlled by setting different duty ratios for the dimming control signal SD1 and the dimming control signal SD2, so as to adjust the brightness of the corresponding light bar. In the backlight driving circuit 1000 of the embodiment of the invention, only one backlight driver 100 is used to provide the driving signal Vout, thereby avoiding the need to provide a separate backlight driving circuit 1000 for each light bar, and reducing the manufacturing cost of the backlight system.
It is easily understood that the first transistor M11a and the second transistor M11b in the first control unit 211 may also be P-type thin film transistors.
In some embodiments, the duty cycles of the dimming control signal SD1 and the dimming control signal SD2 are different. The start time of the light bars corresponding to the first control unit 211, the second control unit 212, the third control unit 213, the fourth control unit 214, the fifth control unit 215 and the sixth control unit 216 can be controlled by setting different duty ratios, so as to adjust the brightness of the corresponding light bars. The duty ratio of the dimming control signal SD can be set according to the working requirement of the light bar.
In some embodiments, enable signal SE1, enable signal SE2, and enable signal SE3 are asserted row by row. Taking the enable signal SE1 as active, the enable signal SE2 and the enable signal SE3 as inactive, when the enable signal SE1 is active, the enable signal SE2 and the enable signal SE3 are inactive, the first control unit 211 circularly shifts and processes the dimming control signal SD1 to obtain the first control signal T11, when the first control signal T11 is active, the driving signal Vout is provided to the light bar corresponding to the first control unit 211, and when the first control signal T11 is inactive, the light bar corresponding to the first control unit 211 is not provided with a signal, that is, the 0 level is provided to the light bar corresponding to the first control unit 211; the second control unit 212 cyclically shifts the dimming control signal SD2 to obtain the first control signal T12, and when the first control signal T12 is asserted, the driving signal Vout is provided to the corresponding light bar of the second control unit 212, and when the first control signal T12 is deasserted, the driving signal Vout is not provided to the corresponding light bar of the second control unit 212, that is, the level 0 is provided to the corresponding light bar of the second control unit 212. The third control unit 213 takes the dimming control signal SD1 as the second control signal T23, and provides the driving signal Vout to the light bar corresponding to the third control unit 213 when the second control signal T23 is active, and does not provide a signal to the light bar corresponding to the third control unit 213, that is, provides a level of 0 to the light bar corresponding to the third control unit 213 when the second control signal T23 is inactive. The fourth control unit 214 uses the dimming control signal SD2 as the second control signal T24, and provides the driving signal Vout to the light bar corresponding to the fourth control unit 214 when the second control signal T24 is active, and does not provide a signal to the light bar corresponding to the fourth control unit 214 when the second control signal T24 is inactive, that is, provides a 0 level to the light bar corresponding to the fourth control unit 214. The fifth control unit 215 uses the dimming control signal SD1 as the second control signal T25, and provides the driving signal Vout to the light bar corresponding to the fifth control unit 215 when the second control signal T25 is asserted, and does not provide a signal to the light bar corresponding to the fifth control unit 215 when the second control signal T25 is de-asserted, that is, provides a level of 0 to the light bar corresponding to the fifth control unit 215. The sixth control unit 216 uses the dimming control signal SD2 as the second control signal T26, and provides the driving signal Vout to the light bar corresponding to the sixth control unit 216 when the second control signal T26 is active, and does not provide a signal to the light bar corresponding to the sixth control unit 216 when the second control signal T26 is inactive, that is, provides a 0 level to the light bar corresponding to the sixth control unit 216.
Fig. 4 is a flowchart illustrating a backlight driving control method according to an embodiment of the present invention. The backlight driving circuit is the backlight driving circuit 1000 in the above embodiment. The backlight driving circuit 1000 includes a backlight driver 100 and a controller 200, the controller 200 includes a plurality of control units arranged in an array, the plurality of control units are arranged corresponding to the plurality of light bars, each control unit includes an enable end E and a driving end D, the enable end E receives an enable signal SE, and the driving end D receives a dimming control signal SD. As shown in fig. 4, the backlight driving control method includes:
step S410: the backlight driver provides a driving voltage.
Step S420: and for each control unit, receiving a driving voltage, when an enable signal is effective, circularly shifting and processing the dimming control signal to obtain a first control signal, and when the first control signal is effective, providing the driving signal for the lamp strip corresponding to the control unit.
Step S430: for each control unit, when the enable signal is invalid, the dimming control signal is used as a second control signal, and when the second control signal is valid, the driving signal is provided for the light bar corresponding to the control unit.
In some embodiments, the enable terminals E of the control units in the same row are all connected to the same enable signal SE, and the drive terminals D of the control units in the same column are all connected to the same dimming control signal SD.
In some embodiments, the plurality of control units include a plurality of columns of control units, and the driving terminals D of the plurality of columns of control units are respectively connected to the plurality of dimming control signals SD, and the backlight driving control method includes:
different duty ratios are set for at least two dimming control signals SD among the plurality of dimming control signals SD.
In some embodiments, the plurality of control units include a plurality of rows of control units, enable terminals E of the plurality of rows of control units are respectively connected to a plurality of enable signals SE, and the backlight driving control method includes:
the enable terminals E of the multi-row control units are supplied with an active enable signal SE on a row-by-row basis.
Since the operation principle of the backlight driving circuit in the embodiment of the present invention has been described in detail in the above embodiment, it is not described herein again.
Correspondingly, an embodiment of the present invention further provides a display device, including:
the backlight driving circuit according to any of the above embodiments.
According to the backlight driving circuit, the backlight driving control method and the display device provided by the embodiment of the invention, the backlight driving circuit comprises a backlight driver and a controller, wherein the backlight driver is used for providing driving voltage; the controller comprises a plurality of control units which are arranged in an array, the control units receive driving voltage respectively, and the control units are arranged corresponding to the light bars. The control unit comprises an enabling end and a driving end, the enabling end receives an enabling signal, the driving end receives a dimming control signal, when the enabling signal is effective, the dimming control signal is processed through cyclic shift to obtain a first control signal, when the first control signal is effective, the driving signal is provided for a lamp bar corresponding to the control unit, when the enabling signal is ineffective, the dimming control signal serves as a second control signal, and when the second control signal is effective, the driving signal is provided for the lamp bar corresponding to the control unit. The starting time of the light bar corresponding to each control unit can be controlled by setting different duty ratios for the dimming control signal, so that the brightness of the corresponding light bar is adjusted, and an independent backlight driving circuit is prevented from being arranged for each light bar, so that the manufacturing cost of the backlight system is reduced.
The control unit includes: the circuit comprises a first transistor, a second transistor, a shift register, a current source and a third resistor. The first end of the third resistor receives the dimming control signal, the second end of the third resistor is connected with the input end of the shift register, the control end of the first transistor receives the enable signal, the first path end is connected with the connection node of the second end of the third resistor and the input end of the shift register, and the second path end is connected with the output end of the shift register. The control end of the second transistor is connected with a connection node of a second path end of the first transistor and the output end of the shift register, the second path end receives the driving voltage, the first path end is connected with the input end of the current source, and the output end of the current source provides the driving signal. The input end of the shift register is isolated from the input dimming control signal by the resistor, so that the shift register is prevented from being short-circuited with the corresponding dimming control signal.
The plurality of control units comprise a plurality of columns of control units, the driving ends of the plurality of columns of control units are respectively connected to the plurality of dimming control signals, and the duty ratios of at least two dimming control signals in the plurality of dimming control signals are different. The starting time of the light bars corresponding to each row of control units can be controlled by setting different duty ratios for the dimming control signals, and then the brightness of the corresponding light bars is adjusted.
The plurality of control units include a plurality of rows of control units, enable terminals of the plurality of rows of control units are respectively connected to a plurality of enable signals, and the plurality of enable signals are asserted row by row. Through the validity of the control enabling signal, the light bar corresponding to each control unit can be continuously displayed. When the enable signals are simultaneously effective, the light bars corresponding to each row of control units can be simultaneously and continuously displayed, and therefore the maximum brightness of the backlight source is improved.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
While embodiments in accordance with the invention have been described above, these embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments described. The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.
Claims (10)
1. A backlight driving circuit, comprising:
a backlight driver for providing a driving voltage;
the controller comprises a plurality of control units which are arranged in an array, the control units respectively receive the driving voltage, the control units are arranged corresponding to the light bars, each control unit comprises an enabling end and a driving end, the enabling end receives an enabling signal, the driving end receives a dimming control signal, when the enabling signal is effective, the dimming control signal is processed through cyclic shift to obtain a first control signal, and when the first control signal is effective, the driving signal is provided for the light bar corresponding to the control unit,
and when the enable signal is invalid, the dimming control signal is used as a second control signal, and when the second control signal is valid, the driving signal is provided for the lamp strip corresponding to the control unit.
2. The backlight driving circuit according to claim 1, wherein the enable terminals of the control units in the same row are all connected to the same enable signal, and the driving terminals of the control units in the same column are all connected to the same dimming control signal.
3. The backlight driving circuit according to claim 1 or 2, wherein each of the control units comprises: the circuit comprises a first transistor, a second transistor, a shift register, a current source and a third resistor;
a first end of the third resistor receives the dimming control signal, a second end of the third resistor is connected with the input end of the shift register, a control end of the first transistor receives the enable signal, a first path end is connected with a connection node between the second end of the third resistor and the input end of the shift register, a second path end is connected with the output end of the shift register,
the control end of the second transistor is connected with a connection node between the second path end of the first transistor and the output end of the shift register, the second path end receives the driving voltage, the first path end is connected with the first end of the current source, and the second end of the current source provides the driving signal.
4. The backlight driving circuit according to claim 2, wherein the plurality of control units comprise a plurality of columns of control units, driving terminals of the plurality of columns of control units are respectively connected to a plurality of dimming control signals, and duty ratios of at least two dimming control signals in the plurality of dimming control signals are different.
5. The backlight driving circuit according to claim 2, wherein the plurality of control units comprise a plurality of rows of control units, the enable terminals of the plurality of rows of control units are respectively connected to a plurality of enable signals, and the plurality of enable signals are active row by row.
6. A display device, comprising:
a backlight driver circuit as claimed in any one of claims 1 to 5.
7. A backlight driving control method for a backlight driving circuit, the backlight driving circuit comprising a backlight driver and a controller, the controller comprising a plurality of control units arranged in an array, the plurality of control units being arranged corresponding to a plurality of light bars, each of the control units comprising an enable terminal and a driving terminal, the enable terminal receiving an enable signal, the driving terminal receiving a dimming control signal, the backlight driving control method comprising:
providing a driving voltage by using the backlight driver;
for each control unit, receiving the driving voltage, when the enable signal is valid, circularly shifting and processing the dimming control signal to obtain a first control signal, when the first control signal is valid, providing the driving signal to the light bar corresponding to the control unit,
and when the enable signal is invalid, the dimming control signal is used as a second control signal, and when the second control signal is valid, the driving signal is provided for the lamp strip corresponding to the control unit.
8. The backlight driving control method according to claim 7, wherein the enable terminals of the control units in the same row are all connected to the same enable signal, and the drive terminals of the control units in the same column are all connected to the same dimming control signal.
9. The backlight driving control method according to claim 8, wherein the plurality of control units comprise a plurality of columns of control units, driving terminals of the plurality of columns of control units are respectively connected to a plurality of dimming control signals, the backlight driving control method comprising:
different duty cycles are set for at least two of the plurality of dimming control signals.
10. The backlight driving control method according to claim 8, wherein the plurality of control units comprise a plurality of rows of control units, enable terminals of the plurality of rows of control units are respectively connected to a plurality of enable signals, the backlight driving control method comprising:
and providing effective enabling signals to the enabling ends of the multi-row control units row by row.
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| CN112382241B (en) | 2022-03-25 |
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