CN117935743B - Backlight light source partition dimming control method, circuit and LED driving chip - Google Patents
Backlight light source partition dimming control method, circuit and LED driving chip Download PDFInfo
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Abstract
The invention provides a backlight light source partition dimming control method, a circuit and LED driving chips, wherein the method comprises the steps that a plurality of LED driving chips form at least one daisy chain in a cascading mode; the controller sends a chip numbering command to a first LED driving chip on the daisy chain; the LED driving chip carries out self-adaptive numbering; the controller sends a brightness update command to a first LED driving chip on the daisy chain, and after the LED driving chip receives the brightness update command, the controller judges whether the brightness of the first LED driving chip needs to be updated, if so, the controller reads corresponding brightness information and sends the brightness update command to the next LED driving chip; if not, directly sending the brightness updating command to the next LED driving chip. The invention can realize the self-adaptive numbering of the cascaded LED driving chips; the brightness update command flexibly sets the number of the starting/stopping chip, so that the brightness of the LED driving chips in the range of the number is updated, the brightness refresh of the single/batch LED driving chips is realized, and the dimming mode is more flexible and efficient.
Description
Technical Field
The invention relates to the technical field of liquid crystal display screen partition backlight control, in particular to a backlight light source partition dimming control method, a circuit and an LED driving chip
Background
The Liquid crystal inside the Liquid crystal display (Liquid CRYSTAL DISPLAY, LCD) does not self-emit light, and a backlight needs to be built in to light the screen. Currently, an LED (LIGHTING EMITTING Diode) backlight source is provided multiple times, and the LED backlight source is dynamically dimmed. Dynamic dimming of LED backlight sources can be divided into Global dimming (Global dimming) and Local dimming (Local dimming). Compared with a global dimming mode, the partition dimming has the advantages of high brightness, high contrast ratio and the like, and can bring better display effect to users.
The chinese patent application No. 202311570016.1 discloses a control method of a backlight unit, a dimming controller and a display device, wherein the dimming controller transmits dimming data to a plurality of columns of LED driving chips (each column of LED driving chips is a daisy chain) connected thereto, the dimming data includes dimming data of all the LED driving chips in the column, and each LED driving chip reads its corresponding dimming data and then transmits the dimming data after its dimming data to the next LED driving chip. In the technical scheme disclosed in the patent application, the dimming data sent by the dimming controller need to comprise the dimming data of each LED driving chip on each daisy chain, so that the data transmission quantity is large; when the dimming data of some LED driving chips do not need to be updated, the dimming controller still can send the dimming data of the LED driving chips, so that dimming can not be performed in a more flexible and efficient mode, and resource waste is caused.
Disclosure of Invention
In order to solve at least one of the technical problems, the invention provides a backlight light source partition dimming control method, an LED driving chip and a circuit.
The first aspect of the present invention provides a backlight light source zoned dimming control method, comprising:
The plurality of LED driving chips form at least one daisy chain in a cascading mode, and the first LED driving chip of each daisy chain is connected with the controller;
The controller sends a chip numbering command comprising a number to a first LED driving chip on the daisy chain;
After receiving the chip numbering command, the LED driving chip takes the number in the chip numbering command as the self number; adding one to the number in the chip number command, and then sending the chip number command to the next LED driving chip connected with the chip number command until the last LED driving chip of the daisy chain receives the chip number command to finish the number;
The controller sends a brightness update command comprising a number and brightness information to a first LED driving chip on the daisy chain;
After receiving the brightness updating command, the LED driving chip judges whether the brightness updating command needs to be updated according to the number in the brightness updating command, if so, reads the corresponding brightness information and sends the brightness updating command to the next LED driving chip connected with the brightness updating command; if not, directly sending the brightness updating command to the next LED driving chip connected with the brightness updating command; until the last LED driving chip on the daisy chain receives the brightness updating command.
Preferably, the chip number command includes: a start identification bit, a number bit, and a termination identification bit.
Preferably, in any of the above aspects, the brightness update command includes: a start identification bit, a start chip number, a stop chip number, luminance data, and a stop identification bit.
In any of the above embodiments, it is preferable that the total length of the luminance data in the luminance update command issued by the controller=the total number M of LED driving chips in the luminance update command, the number N of channels per LED driving chip, and the length L of the luminance data per channel.
In any of the above embodiments, it is preferable that the luminance data in the luminance update command sent by the controller is arranged in the order of the numbers of the LED driving chips, that is, the data of the length of n×l at the beginning of the luminance data is the luminance data of the LED driving chip having the starting chip number; the second data of length n×l is the brightness data of the LED driving chip with (initial chip number+1); similarly, the last data of length n×l is the brightness data of the LED driving chip with the termination chip number.
In any of the above embodiments, it is preferable that if the LED driving chip determines that the number thereof is within the range of [ start chip number, end chip number ], it is determined that the brightness thereof needs to be updated.
In any of the above embodiments, it is preferable that, for a certain backlight source brightness update, the brightness update command sent by the controller includes only the number of the LED driving chip that needs to be updated, and the number of the LED driving chip that does not need to be updated does not appear in the brightness update command sent by the controller.
A second aspect of the present invention provides a backlight light source zoned dimming circuit comprising: the LED driving chips form at least one daisy chain in a cascading mode, and the first LED driving chip of each daisy chain is connected with the controller;
The controller is configured to send a chip number command including a number and a brightness update command including a number and brightness information to a first LED driver chip on the daisy chain;
The LED driving chip is configured to take the serial number in the chip as the self serial number after receiving the chip serial number command; adding one to the number in the chip number command, and then sending the chip number command to the next LED driving chip connected with the chip number command; judging whether the brightness is required to be updated according to the number in the brightness updating command after the brightness updating command is received, if so, reading the corresponding brightness information, and sending the brightness updating command to the next LED driving chip connected with the brightness updating command; if not, the brightness updating command is directly sent to the next LED driving chip connected with the brightness updating command.
Preferably, the clock signal input pin and the data signal input pin of the first LED driving chip on the daisy chain are connected with one SPI interface of the front-stage controller in a one-to-one correspondence manner.
A third aspect of the present invention provides an LED driving chip for backlight light source zone dimming, the LED driving chip configured to receive a chip number command including a number, and a luminance update command including a number and luminance information; after receiving the chip number command, taking the number in the chip number command as the self number, adding one to the number in the chip number command, and then sending the chip number command to the next LED driving chip connected with the chip number command; after receiving the brightness updating command, judging whether the brightness updating command needs to be updated according to the number in the brightness updating command, if so, reading the corresponding brightness information, and sending the brightness updating command to the next LED driving chip connected with the brightness updating command; if not, the brightness updating command is directly sent to the next LED driving chip connected with the brightness updating command.
Preferably, the LED driving chip includes:
A clock signal input pin configured to receive a clock signal transmitted from a previous stage chip;
A clock signal output pin configured to output a clock signal received by an LED driving chip to a next LED driving chip connected to the LED driving chip;
a data signal input pin configured to receive a data signal transmitted from a previous chip;
and a data signal output pin configured to output a data signal received by the LED driving chip to a next LED driving chip connected to the LED driving chip.
In any of the above embodiments, it is preferable that the previous stage chip includes a previous LED driving chip connected to the LED driving chip, or a controller connected to the LED driving chip.
The backlight light source partition dimming control method, the circuit and the LED driving chip have the following beneficial effects:
1. the self-adaptive numbering of the cascaded LED driving chips can be realized through the chip numbering command;
2. After the LED driving chips are numbered, the brightness updating command can flexibly set the starting chip number and the ending chip number, so that the brightness of the LED driving chips only in the number range is updated, the brightness writing of a single brightness updating command to single or multiple LED driving chips is completed, the brightness refreshing of single/batch LED driving chips is further realized, and the dimming mode is more flexible and efficient;
3. The brightness update command can be sent only to the LED driving chip needing dimming, so that resources are saved;
4. The wiring modes between the LED driving chips and the controller simplify the wiring of the PCB, and the cost is saved.
Drawings
Fig. 1 is a flowchart of a method for controlling the dimming of a backlight light source according to a preferred embodiment of the present invention.
Fig. 2 is a schematic diagram of a backlight light source partition dimming circuit according to a preferred embodiment of the present invention.
Fig. 3 is a schematic diagram of a chip number command structure of the embodiment shown in fig. 1 according to the backlight light source zone dimming control method of the present invention.
Fig. 4 is a schematic diagram of a brightness update command structure of the embodiment shown in fig. 1 according to the backlight light source zone dimming control method of the present invention.
Fig. 5 is a schematic diagram of a brightness update command according to the embodiment shown in fig. 1 of the backlight light source zone dimming control method according to the present invention.
Fig. 6 is a schematic diagram of a brightness update command according to the embodiment shown in fig. 1 of the backlight light source zone dimming control method according to the present invention.
Detailed Description
The invention will be described in more detail with reference to specific examples.
Embodiment 1 as shown in fig. 1, a backlight light source zoned dimming control method includes:
Step 1: the plurality of LED driving chips form at least one daisy chain in a cascading mode, and the first LED driving chip of each daisy chain is connected with the controller;
step 2: the controller sends a chip numbering command comprising a number to a first LED driving chip on the daisy chain;
Step 3: after receiving the chip numbering command, the LED driving chip takes the number in the chip numbering command as the self number; adding one to the number in the chip number command, and then sending the chip number command to the next LED driving chip connected with the chip number command until the last LED driving chip of the daisy chain receives the chip number command to finish the number;
Step 4: the controller sends a brightness update command comprising a number and brightness information to a first LED driving chip on the daisy chain;
step 5: after receiving the brightness updating command, the LED driving chip judges whether the brightness updating command needs to be updated according to the number in the brightness updating command, if so, reads the corresponding brightness information and sends the brightness updating command to the next LED driving chip connected with the brightness updating command; if not, directly sending the brightness updating command to the next LED driving chip connected with the brightness updating command; until the last LED driving chip on the daisy chain receives the brightness updating command.
To perform the method, a backlight light source zoned dimming circuit is provided, comprising: the LED driving chips form at least one daisy chain in a cascading mode, and the first LED driving chip of each daisy chain is connected with the controller;
The controller is configured to send a chip number command including a number and a brightness update command including a number and brightness information to a first LED driver chip on the daisy chain;
The LED driving chip is configured to take the serial number in the chip as the self serial number after receiving the chip serial number command; adding one to the number in the chip number command, and then sending the chip number command to the next LED driving chip connected with the chip number command; judging whether the brightness is required to be updated according to the number in the brightness updating command after the brightness updating command is received, if so, reading the corresponding brightness information, and sending the brightness updating command to the next LED driving chip connected with the brightness updating command; if not, the brightness updating command is directly sent to the next LED driving chip connected with the brightness updating command.
The LED driving chip includes:
A clock signal input pin configured to receive a previous chip transmit clock signal;
A clock signal output pin configured to output a clock signal received by an LED driving chip to a next LED driving chip connected to the LED driving chip;
a data signal input pin configured to receive a data signal transmitted from a previous stage chip; and
And a data signal output pin configured to output a data signal received by the LED driving chip to a next LED driving chip connected to the LED driving chip.
The front stage chip comprises a front LED driving chip connected with the LED driving chip or a controller connected with the LED driving chip.
Specifically, when the backlight source is used for dimming in a partition mode, a plurality of LED driving chips are needed to drive the LED lamp strings of the backlight source, each LED driving chip is provided with at least one channel, and each channel can output driving signals to one LED lamp string, so that the luminous brightness of the LED lamp string is controlled, and the dimming of the backlight partition corresponding to the LED lamp string is realized. The number of the LED driving chips required by the backlight source partition dimming is determined according to the number of the backlight source partitions, the number of channels of the LED driving chips and the like.
After the specific number of the required LED driving chips is determined, in step 1, at least one daisy chain is formed by the LED driving chips with the corresponding number in a cascading manner, and the first LED driving chip of each daisy chain is connected with a controller. FIG. 2 illustrates one embodiment of a backlight source zoned dimming circuit, it being noted that in FIG. 2, only two daisy chains are shown, the other daisy chains being omitted from the display; and for each LED driving chip, only one LED light string driven by the LED driving chip is shown, and other LED light strings are omitted from display. For convenience of description, one daisy chain located above shown in fig. 2 is referred to as a first daisy chain, and the other daisy chain shown in fig. 2 is referred to as a second daisy chain.
In this embodiment, as shown in fig. 2, taking a first daisy chain as an example, the clock signal output pin CLKO of a first LED driving chip on the daisy chain is connected to the clock signal input pin CLKI of a second LED driving chip on the daisy chain, so that the first LED driving chip outputs the clock signal received by the first LED driving chip to the second LED driving chip; meanwhile, the data signal output pin SOUT of the first LED driving chip on the daisy chain is connected with the data signal input pin SIN of the second LED driving chip on the daisy chain, so that the first LED driving chip outputs the received data signal to the second LED driving chip. Likewise, the clock signal output pin CLKO of the second LED driving chip on the daisy chain is connected with the clock signal input pin CLKI of the third LED driving chip on the daisy chain, so that the second LED driving chip outputs the clock signal received by the second LED driving chip to the third LED driving chip; meanwhile, the data signal output pin SOUT of the second LED driving chip on the daisy chain is connected with the data signal input pin SIN of the third LED driving chip on the daisy chain, so that the second LED driving chip outputs the received data signal to the third LED driving chip. And so on. The clock signal output pin CLKO of the last LED driving chip is connected with the clock signal input pin CLKI of the last LED driving chip on the daisy chain, so that the last LED driving chip outputs the clock signal received by the last LED driving chip to the last LED driving chip; meanwhile, the data signal output pin SOUT of the last LED driving chip on the daisy chain is connected with the data signal input pin SIN of the last LED driving chip on the daisy chain, so that the last LED driving chip outputs the received data signal to the last LED driving chip. The other daisy chains in the backlight source zone dimming circuit are connected with reference to the first daisy chain. Meanwhile, a clock signal input pin CLKI and a data signal input pin SIN of a first LED driving chip of the first daisy chain are connected with a first SPI interface of the controller to respectively receive the clock signal and the data signal sent by the controller. The clock signal input pin CLKI and the data signal input pin SIN of the first LED driving chip of the second daisy chain are connected with the second SPI interface of the controller so as to respectively receive the clock signal and the data signal sent by the controller. Connection of other daisy chains to the controller and so on.
It should be noted that, when one controller cannot meet the control requirements of all the daisy chains, multiple controllers may be used to control the daisy chains. It should be further noted that, the connection mode between the LED driving chips and the controller are capable of effectively simplifying the wiring of the PCB board and saving the cost compared with the connection mode in which the clock signal output pins and the data signal output pins of the controller are respectively connected to the clock signal input pins and the data signal input pins of each LED driving chip.
The following description will proceed with the example of one controller controlling all the daisy chains.
Step 2: the controller sends a chip number command including a number to the first LED driver chip on the daisy chain. Step 3: after receiving the chip numbering command, the LED driving chip takes the number in the chip numbering command as the self number; and adding one to the number in the chip number command, and then sending the chip number command to the next LED driving chip connected with the chip number command until the last LED driving chip of the daisy chain receives the chip number command to finish the number.
As shown in fig. 3, the chip number command includes: a start identification bit, a number bit, and a termination identification bit. The start identification bit is used for identifying the command as a chip number command, and the end identification bit is used for identifying the end of the chip number command; the number bits are corresponding numbers. The length of the initial identification bit of the chip numbering command is 16 bits, and the content is 5550; the length of the termination identification bit is 16 bits, the content is 5555, and the length of the number bit is 16 bits for example for the detailed description.
The controller sends a data signal to the data signal input pin SIN of the first LED driver chip on the first daisy chain through the first SPI interface, the data signal including the chip number command 5550 0000 5555, and simultaneously sends a clock signal to the clock signal input pin CLKI of the first LED driver chip on the first daisy chain through the first SPI interface. After the first LED driver chip in the first daisy chain receives the clock signal and the data signal sent by the controller, the content of the data signal is read according to the rising edge or the falling edge of the clock signal, and when 5550 is read, the data signal is judged to include a chip number command, then the 16bit content 0000 after the initial identification bit 5550 is recorded as the own number, the number 0000 is added with 1 and then written into the number bit of the chip number command, then the data signal including the new chip number command 5550 0001 5555 is sent to the data signal input pin SIN of the second LED driver chip through the signal output pin SOUT, and meanwhile, the clock signal is sent to the clock signal input pin CLKI of the second LED driver chip through the clock signal output pin CLKO. The second LED driver chip records the content 0001 of the number bit in the received chip number command as its own number, and sends a new chip number command 5550 0002 5555 to the third LED driver chip after adding 1 to the number 0001. And the analogy is performed until the last LED driving chip receives the chip numbering command, and the content of the numbering bit in the chip numbering command is used as the self-numbering record. The first LED driving chip in the other daisy chains receives the chip numbering command through the communication interface connected with the controller, and finishes numbering from the first LED driving chip to the last LED driving chip. It should be noted that, the last LED driving chip on each daisy chain: (1) Or judging that no other LED driving chips exist after the connection state of the signal output pin SOUT/clock signal output pin CLKO is adopted, and ending the chip numbering process of the daisy chain after the self number is recorded; (2) Or after the self number is recorded and the number bit content is added with 1, ending the chip numbering process of the daisy chain because a new chip numbering command cannot be sent out; it should be understood that, in the present application, only the last LED driving chip in the daisy chain is numbered, and the operation of adding 1 to the number received by the last LED driving chip in the daisy chain is not limited.
For the backlight light source partition dimming circuit in fig. 2, after the step2 and the step3, the LED driving chips on the first daisy chain are numbered sequentially as #0 (No. 0), #1, … …, # T1; the LED driving chips on the second daisy chain are numbered sequentially as #0 (number 0), #1, … …, # T2; likewise, the LED driver chips on the other daisy chains are also numbered sequentially. It should be noted that, step2 and step3 only number the LED driving chips on the daisy chain, and for the controller, by parameter configuration, it knows the number of the LED driving chips on each daisy chain connected thereto, that is, it knows the maximum number of the LED driving chips on each daisy chain connected thereto.
After numbering the LED driving chips is completed, step 4 is executed: the controller sends a brightness update command comprising a number and brightness information to a first LED driving chip on the daisy chain; step 5: after receiving the brightness updating command, the LED driving chip judges whether the brightness updating command needs to be updated according to the number in the brightness updating command, if so, reads the corresponding brightness information and sends the brightness updating command to the next LED driving chip connected with the brightness updating command; if not, directly sending the brightness updating command to the next LED driving chip connected with the brightness updating command; until the last LED driving chip on the daisy chain receives the brightness updating command.
As shown in fig. 4, the brightness update command includes: the system comprises a start identification bit, a start chip number, a termination chip number, brightness data and a termination identification bit, wherein the start identification bit is used for identifying that the command is a brightness update command, and the termination identification bit is used for identifying that the brightness update command is ended; the starting chip number and the ending chip number indicate that the brightness update command is used for updating brightness of the LED driving chips with the numbers on the daisy chain, and the LED driving chips update brightness according to the brightness data. The length of the initial identification bit of the brightness update command is 16 bits, and the content is 5560; the length of the termination identification bit is 16 bits, and the content is FFFF; the length of the start chip number and the end chip number is 16 bits, the number of channels of each LED driving chip is n=4, and the length of the luminance data of each channel is l=16 bits.
The controller sends a data signal to a data signal input pin SIN of a first LED driving chip on the first daisy chain through a first SPI interface, the data signal comprises a brightness updating command, and simultaneously sends a clock signal to a clock signal input pin CLKI of the first LED driving chip on the first daisy chain through the first SPI interface. Taking the luminance update command (5560 0007 0007 1000 1110 1001 1101 FFFF) shown in fig. 5 as an example, the luminance update command only acts on the LED driving chip numbered 0007, where the length of the luminance data is m×n×l=1×4×16 bit=64 bit. After the first LED driving chip on the first daisy chain receives the clock signal and the data signal sent by the controller, the content of the data signal is read according to the rising edge or the falling edge of the clock signal, when 5560 is read, the data signal is judged to comprise a brightness updating command, then whether the number of the first LED driving chip is within the range of [ initial chip number and end chip number ] in the brightness updating command is judged, namely whether the number 0000 of the first LED driving chip is within the range of [0007 and 0007], the judgment result is no, the data signal comprising the brightness updating command is directly sent to the second LED driving chip, and meanwhile, the clock signal is sent to the second LED driving chip. After the second LED driving chip receives the brightness update command, similarly, it determines whether the number 0001 of the second LED driving chip is within the range of [ initial chip number, end chip number ], that is, within the range of [0007, 0007], and if not, directly sends the data signal including the brightness update command to the third LED driving chip, and simultaneously sends the clock signal to the third LED driving chip. And the like, until the eighth LED driving chip on the daisy chain receives the brightness updating command, judging whether the own number 0007 is within the range of [ initial chip number, end chip number ], namely [0007, 0007], wherein the judgment result is that the data of N.times.L=4.times.16bit=64 bit after the end chip number is read is written as brightness data, namely, 1000 1110 1001 1101 is read as self brightness data to be written, so that the LED lamp strings connected with all channels of the LED lamp strings are driven according to the brightness data; and then the data signal comprising the brightness update command is sent to the ninth LED driving chip, and simultaneously a clock signal is sent to the ninth LED driving chip. After the ninth LED driving chip receives the brightness updating command, the ninth LED driving chip judges that the number of the ninth LED driving chip is not in the range of [ initial chip number and end chip number ], namely [0007, 0007], directly sends the data signal comprising the brightness updating command to the tenth LED driving chip, and simultaneously sends a clock signal to the tenth LED driving chip. The last LED driving chip (the number of which is T1 in the figure 2) on the daisy chain receives the brightness updating command, and judges that the number of the last LED driving chip is not in the range of [ initial chip number, end chip number ], namely [0007, 0007 ]. It should be noted that, since the last LED driving chip on the daisy chain has no next LED driving chip connected thereto, the data signal including the brightness update command received by the last LED driving chip is not sent to the next LED driving chip connected thereto; that is, it only determines whether the number of the user is within the range of the initial chip number and the final chip number to determine whether the user needs to update the luminance information, and reads the corresponding luminance information if so.
The controller sends data signals to the data signal input pin SIN of the first LED driving chip on the second daisy chain through the second SPI interface, the data signals comprise brightness updating commands, and simultaneously sends clock signals to the clock signal input pin CLKI of the first LED driving chip on the second daisy chain through the second SPI interface. An example of a luminance update command (5560 0003 000A 1000 1110 … … 1001 FFFF) shown in fig. 6, which acts on the LED driving chips numbered 0003 to 000A, will be described. It should be noted that 5560 is a start flag of the brightness update command, 0003 is a start chip number, 000A is a stop chip number, 1000 1110 … … 1001 1101 is brightness data, the length of which is m×n×l=8×4×16 bit=512 b it, and ffff is a stop flag. After the first LED driving chip on the second daisy chain receives the clock signal and the data signal sent by the controller, the content of the data signal is read according to the rising edge or the falling edge of the clock signal, when 5560 is read, the data signal is judged to comprise a brightness updating command, then whether the number of the first LED driving chip is within the range of [ initial chip number and end chip number ] in the brightness updating command is judged, namely whether the number 0000 of the first LED driving chip is within the range of [0003,000A ], the judgment result is no, the data signal comprising the brightness updating command is directly sent to the second LED driving chip, and meanwhile, the clock signal is sent to the second LED driving chip. After the second LED driving chip receives the brightness update command, similarly, it determines whether the number 0001 of the second LED driving chip is within the range of [ initial chip number, end chip number ], that is, within the range of [0003, 000A ], and if not, directly sends the data signal including the brightness update command to the third LED driving chip, and simultaneously sends the clock signal to the third LED driving chip. And the like, until the fourth LED driving chip on the daisy chain receives the brightness updating command, judging whether the own number 0003 is within the range of [ initial chip number, end chip number ], namely [0003, 000A ], wherein the judgment result is that the data with the length of N, L=4, 16 bit=64 bit in the first brightness data is read and written as the self brightness data, so that the LED lamp strings connected with all channels of the LED lamp strings are driven according to the brightness data; and then the data signal comprising the brightness updating command is sent to the fifth LED driving chip, and a clock signal is sent to the fifth LED driving chip. After receiving the brightness update command, the fifth LED driving chip determines that its own number 0004 is within the range of [ initial chip number, end chip number ], that is, within the range of [0003, 000A ], reads the second data with the length of n×l=4×16bit=64 bit from the brightness data, and writes the second data as self brightness data, so as to drive the LED light string connected with each channel according to the brightness data; and then transmitting the data signal comprising the brightness update command to the sixth LED driving chip, and simultaneously transmitting a clock signal to the sixth LED driving chip. And the like, until the eleventh LED driving chip receives the brightness updating command, judging that the number 000A of the eleventh LED driving chip is in the range of [ initial chip number, ending chip number ], namely [0003, 000A ], and reading the last N x L=4 x 16 bit=64 bit length data in the brightness data as self brightness data, so as to drive the LED lamp strings connected with all channels according to the brightness data; and then transmitting the data signal comprising the brightness update command to the twelfth LED driving chip, and simultaneously transmitting a clock signal to the twelfth LED driving chip. After the twelfth LED driving chip receives the brightness updating command, the twelfth LED driving chip judges that the number 000B of the twelfth LED driving chip is not in the range of [ initial chip number and end chip number ], namely [0003, 000A ], directly sends the data signal comprising the brightness updating command to the thirteenth LED driving chip, and simultaneously sends the clock signal to the thirteenth LED driving chip. The last LED driving chip (the number of which is T2 in the figure 2) on the daisy chain receives the brightness updating command, and judges that the number of the last LED driving chip is not in the range of [ initial chip number, end chip number ], namely [0003, 000A ]. It should be noted that, since the last LED driving chip on the daisy chain has no next LED driving chip connected thereto, the data signal including the brightness update command received by the last LED driving chip is not sent to the next LED driving chip connected thereto; that is, it only determines whether the number of the user is within the range of the initial chip number and the final chip number to determine whether the user needs to update the luminance information, and reads the corresponding luminance information if so.
The brightness update command sent by the controller to the other daisy chains is processed in the manner described above.
In this embodiment, it is preferable that, in the luminance update command, for a single LED driving chip, the luminance data length of the single LED driving chip is 64 bits, the luminance data of each channel is 16 bits, and in this embodiment, it is further preferable that the luminance data of the first 16 bits is the luminance data of the LED string controlled by the first channel of the LED driving chip, the luminance data of the second 16 bits is the luminance data of the LED string controlled by the second channel of the LED driving chip, the luminance data of the third 16 bits is the luminance data of the LED string controlled by the third channel of the LED driving chip, and the luminance data of the fourth 16 bits is the luminance data of the LED string controlled by the fourth channel of the LED driving chip. It should be further noted that, in the present embodiment, the number N of channels of the LED driving chip, the length L of the luminance data of each channel, and the correspondence between the luminance data of a single LED driving chip and each channel thereof are only exemplary.
It should be further noted that, for the backlight source zone dimming circuit, when the backlight source zone dimming method is executed, the step1 is executed only once, after the steps 2 and 3 are executed sequentially, the steps 4 and 5 may be executed sequentially, that is, after the connection between the LED driving chips and the controller is completed, the LED driving chips may be numbered once, and then the brightness update may be executed for a plurality of times.
Embodiment 2 this embodiment is similar to the previous embodiment, except that in this embodiment, it is preferable that, for a certain backlight source brightness update, the brightness update command sent by the controller includes only the number of the LED driving chip that needs brightness update, and the number of the LED driving chip that does not need brightness update does not appear in the brightness update command sent by the controller. For the LED driving chip requiring brightness update, it can be realized by a plurality of brightness update commands. If sixteen LED driving chips are arranged on a certain daisy chain, the serial numbers of the LED driving chips are 0000-000F respectively through chip serial number commands. Some time the brightness of the backlight source is updated, only the brightness of the backlight source partition controlled by the LED driving chip with the numbers of 0003-0006 and 0009-000B needs to be updated, and the brightness of the backlight source partition controlled by the chip with other numbers does not need to be updated, the controller: (1) Two brightness update commands may be sent, one acting on LED driver chips numbered 0003-0006 and the other acting on LED driver chips numbered 0009-000B; (2) More than two brightness update commands may be sent, such as 3, one for the LED driver chips numbered 0003-0005, another for the LED driver chips numbered 0006, and yet another for the LED driver chips numbered 0009-000B. It should be understood that, for the brightness update of the backlight light source, the brightness update command sent by the controller only includes the number of the LED driving chip that needs to be updated, and the number of the LED driving chip that does not need to be updated does not appear in the brightness update command sent by the controller; there is no limitation on how many brightness update commands the controller sends to cover all LED driver chips that need brightness update.
Embodiment 3 this embodiment is similar to the previous embodiment, except that in this embodiment, it is preferable that for a certain backlight source brightness update, the brightness update command sent by the controller covers all LED driving chips, and for all LED driving chips, it can be implemented by a plurality of brightness update commands. If sixteen LED driving chips are arranged on a certain daisy chain, the serial numbers of the LED driving chips are 0000-000F respectively through chip serial number commands. And updating the brightness of the backlight light source for a certain time, and controlling: (1) Two brightness update commands may be sent, one acting on the LED driver chip numbered 0000-0006 and the other acting on the LED driver chip numbered 0007-000F; (2) A brightness update command may be sent, which acts on the LED driver chip numbered 0000-000F; (3) Five brightness update commands may be sent, the first with respect to LED driver chips numbered 0000, the second with respect to LED driver chips numbered 0001-0003, the third with respect to LED driver chips numbered 0004-0008, the fourth with respect to LED driver chips numbered 0009-000C, and the fifth with respect to LED driver chips numbered 000D-000F. It should be understood that, for this brightness update of the backlight light source, the controller only needs to cover all numbered LED driving chips in the brightness update command sent by the controller, and there is no limitation on how many brightness update commands the controller sends to cover all LED driving chips.
Embodiment 4 this embodiment is similar to the foregoing embodiment, except that in this embodiment, it is preferable that in the luminance update command, the start chip number is not greater than the end chip number, and after the LED driver chip receives the luminance update command and determines that it needs to perform luminance update, it intercepts luminance data corresponding to the luminance update command, and then sends remaining luminance data after interception to the next LED driver chip connected to the LED driver chip. For example, the brightness update command sent by the controller to a certain daisy chain is 5560 0000 0001 1000 1110 1111 1010 1100 0000 1001 1101 FFFF. And judging that the LED driving chip with the number 0000 on the daisy chain is required to update the brightness, intercepting the brightness data 1000 1110 1111 1010 corresponding to the LED driving chip with the number 0000 for updating writing, and then sending the intercepted residual brightness data to the LED driving chip with the number 0001 on the daisy chain, namely, sending a brightness updating command 5560 0000 0001 1100 0000 1001 1101 FFFF to the LED driving chip with the number 0001, intercepting the first 4 x 16bit data in the brightness updating command by the LED driving chip with the number 0001 as the brightness data corresponding to the brightness updating command for updating writing, and then sending a brightness updating command 5560 0000 0001 FFFF to the LED driving chip with the number 0002.
It should be noted that the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; while the foregoing embodiments are illustrative of the present invention in detail, those skilled in the art will appreciate that: the technical scheme described in the foregoing embodiments may be modified or some or all of the technical features may be replaced with equivalents, which do not depart from the scope of the technical scheme of the present invention.
Claims (9)
1. A backlight light source zonal dimming control method comprises the following steps:
the plurality of LED driving chips form at least one daisy chain in a cascading mode, and the first LED driving chip of each daisy chain is connected with the controller; the method is characterized in that: further comprises:
The controller sends a chip numbering command comprising a number to a first LED driving chip on the daisy chain;
After receiving the chip numbering command, the LED driving chip takes the number in the chip numbering command as the self number; adding one to the number in the chip number command, and then sending the chip number command to the next LED driving chip connected with the chip number command until the last LED driving chip of the daisy chain receives the chip number command to finish the number;
The controller sends a brightness update command comprising a number and brightness information to a first LED driver chip on the daisy chain, the brightness update command comprising: a start identification bit, a start chip number, a stop chip number, brightness data and a stop identification bit;
After receiving the brightness updating command, the LED driving chip judges whether the brightness updating command needs to be updated according to the number in the brightness updating command, if so, reads the corresponding brightness information and sends the brightness updating command to the next LED driving chip connected with the brightness updating command; if not, directly sending the brightness updating command to the next LED driving chip connected with the brightness updating command; until the last LED driving chip on the daisy chain receives the brightness updating command.
2. The backlight source zone dimming control method as claimed in claim 1, wherein: the chip number command includes: a start identification bit, a number bit, and a termination identification bit.
3. The backlight source zone dimming control method as claimed in claim 2, wherein: total length of luminance data in the luminance update command sent by the controller=total number M of LED driving chips in the luminance update command, number N of channels per LED driving chip, length L of luminance data per channel.
4. The backlight source zone dimming control method as claimed in claim 3, wherein: the brightness data in the brightness update command sent by the controller are arranged according to the sequence of the serial numbers of the LED driving chips, namely, the data with the length of N x L at the beginning in the brightness data are the brightness data of the LED driving chips with the serial numbers of the initial chips; the second data of length n×l is the brightness data of the LED driving chip with the initial chip number +1; similarly, the last data of length n×l is the brightness data of the LED driving chip with the termination chip number.
5. The backlight source zone dimming control method as claimed in claim 1, wherein: if the LED driving chip judges that the number is within the range of the initial chip number and the end chip number, the LED driving chip judges that the brightness needs to be updated.
6. A backlight light source zoned dimming circuit comprising: the LED driving chips form at least one daisy chain in a cascading mode, and the first LED driving chip of each daisy chain is connected with the controller; the method is characterized in that:
The controller is configured to send a chip number command including a number and a brightness update command including a number and brightness information to a first LED driver chip on the daisy chain;
The LED driving chip is configured to take the serial number in the chip as the self serial number after receiving the chip serial number command; adding one to the number in the chip number command, and then sending the chip number command to the next LED driving chip connected with the chip number command; judging whether the brightness is required to be updated according to the number in the brightness updating command after the brightness updating command is received, if so, reading the corresponding brightness information, and sending the brightness updating command to the next LED driving chip connected with the brightness updating command; if not, directly sending the brightness updating command to the next LED driving chip connected with the brightness updating command;
The brightness update command includes: a start identification bit, a start chip number, a stop chip number, luminance data, and a stop identification bit.
7. The backlight source zoned dimming circuit of claim 6, wherein: the clock signal input pin and the data signal input pin of the first LED driving chip on the daisy chain are connected with one SPI interface of the controller in a one-to-one correspondence mode.
8. LED driving chips for backlight light source partition dimming are formed into at least one daisy chain in a cascading mode, and a first LED driving chip of each daisy chain is connected with a controller, and the LED driving chip is characterized in that: the LED driving chip is configured to receive a chip number command including a number and a brightness update command including a number and brightness information; after receiving the chip number command, taking the number in the chip number command as the self number, adding one to the number in the chip number command, and then sending the chip number command to the next LED driving chip connected with the chip number command; after receiving the brightness updating command, judging whether the brightness updating command needs to be updated according to the number in the brightness updating command, if so, reading the corresponding brightness information, and sending the brightness updating command to the next LED driving chip connected with the brightness updating command; if not, directly sending the brightness updating command to the next LED driving chip connected with the brightness updating command; the brightness update command includes: a start identification bit, a start chip number, a stop chip number, luminance data, and a stop identification bit.
9. The LED driver chip for dimming a backlight source in a divided manner according to claim 8, wherein: comprising the following steps:
A clock signal input pin configured to receive a previous chip transmit clock signal;
A clock signal output pin configured to output a clock signal received by an LED driving chip to a next LED driving chip connected to the LED driving chip;
a data signal input pin configured to receive a data signal transmitted from a previous stage chip; and
And a data signal output pin configured to output a data signal received by the LED driving chip to a next LED driving chip connected to the LED driving chip.
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