CN113766697B - LED backlight system, driving chip thereof and processing method of main control chip - Google Patents
LED backlight system, driving chip thereof and processing method of main control chip Download PDFInfo
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
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Abstract
The invention provides an LED backlight system, a driving chip thereof and a processing method of a main control chip, wherein the processing method of the driving chip comprises the following steps: obtaining deviation information, the deviation information characterizing: the deviation degree and the deviation mode of the clock frequency between the driving chip and the main control chip connected with the driving chip are larger or smaller; receiving dimming information sent by the main control chip; and compensating the dimming information based on the deviation information, and outputting a dimming signal based on the compensated dimming information. The scheme provided by the invention ensures the consistency of time response among the driving chips, and on the basis, a phase-locked loop (PLL) is not required to be additionally arranged, so that the cost and the size of the chips are effectively reduced.
Description
Technical Field
The invention relates to the field of LEDs, in particular to an LED backlight system, a driving chip thereof and a processing method of a main control chip.
Background
In the field of LED backlight driving, in order to realize dynamic zonal dimming, it is necessary to dynamically control the brightness of LED beads of multiple channels. The LED backlight system can comprise LED driving chips and a main control chip, the number of LED channels which can be provided by a single LED driving chip is limited, a plurality of LED driving chips are often needed in one LED backlight plate, the main control chip controls the plurality of LED driving chips through a digital transmission interface, then the main control chip can send dimming information (also can be understood as dimming parameters) to the LED driving chips, and the LED driving chips can send dimming signals to connected LED lamp beads based on the dimming information.
If the main control chip needs to broadcast dimming information to a plurality of LED driving chips, the main control chip: the better the consistency of the time response of the dimming information of the plurality of LED driving chips, the better the final dimming effect. In the prior art, a SYNC pin needs to be added to the LED driving chip to transmit SYNC synchronization signals, and a phase-locked loop PLL needs to be included in the LED driving chip. The LED driving chips which need to be synchronized share the same periodical SYNC signal, and the phase-locked loop PLL inside each chip tracks the SYNC signal, so that the consistency of the inter-chip time reference is realized.
However, in this way, the introduction of SYNC pins and PLL will increase the size and cost of the chip, especially when the number of LED beads is large, the increase in size and cost will be very significant.
Disclosure of Invention
The invention provides an LED backlight system, a driving chip thereof and a processing method of a main control chip, which are used for solving the problems of increasing the chip size and the cost.
According to a first aspect of the present invention, there is provided a method for processing a driving chip in an LED backlight system, including:
obtaining deviation information, the deviation information characterizing: the deviation degree and the deviation mode of the clock frequency between the driving chip and the main control chip connected with the driving chip are larger or smaller;
Receiving dimming information sent by the main control chip;
and compensating the dimming information based on the deviation information, and outputting a dimming signal based on the compensated dimming information.
Optionally, acquiring the deviation information includes:
acquiring reference counting information;
in the process of counting the reference counting information by the main control chip, counting by using a counter of the driving chip to obtain corresponding local counting information;
the offset information is determined based on the local count information and the reference count information.
Optionally, the deviation information is a ratio of the local count information to the reference count information, or information obtained based on the ratio.
Optionally, in the process that the main control chip counts the reference counting information, a counter of the driving chip is used for counting to obtain corresponding local counting information, including:
receiving a start command and an end command sent by the main control chip, and controlling a counter of the driving chip to count based on the start command and the end command to obtain the local count information;
wherein a time interval between the end command and the start command matches: and the counter of the main control chip counts the time length of the reference counting information.
Optionally, receiving a start command and an end command sent by the main control chip, and controlling a counter of the driving chip to count based on the start command and the end command, so as to obtain the local count information, where the method includes:
when a start command sent by the main control chip is received, starting counting by using a counter of the driving chip;
and stopping counting of the counter of the driving chip when receiving the finishing command sent by the main control chip, and obtaining the local counting information.
According to a second aspect of the present invention, there is provided a method for processing a main control chip in an LED backlight system, including:
determining reference counting information, and broadcasting the reference counting information to a driving chip connected with the main control chip;
Broadcasting a start command to the driving chip, and starting counting by using a counter of the main control chip;
When the counter completes counting of the reference count information, broadcasting an ending command to the driving chip so that: the driving chip can control a counter of the driving chip to count based on the start command and the finish command to obtain local count information, and determine deviation information based on the local count information and the reference count information, wherein the deviation information characterizes the deviation degree and the deviation mode of clock frequency between the main control chip and the driving chip, and the deviation mode refers to larger or smaller;
And sending dimming information to the driving chip so that: the driving chip can compensate the dimming information based on the deviation information and output a dimming signal based on the compensated dimming information.
Optionally, the deviation information is a ratio of the local count information to the reference count information, or information obtained based on the ratio.
According to a third aspect of the present invention, there is provided an LED backlight system comprising:
a driver chip for executing the processing method of the driver chip related to the first aspect and its alternative; and the main control chip.
According to a fourth aspect of the present invention, there is provided a chip for performing the steps of the method of the first and second aspects.
According to a fifth aspect of the present invention there is provided a storage medium having stored thereon code which when executed performs the steps of the method of the first and second aspects.
According to the LED backlight system, the driving chip and the processing method of the main control chip, after the driving chip obtains the deviation information, the dimming information can be compensated, and the dimming signal is output based on the compensated dimming information, so that the driving chip can compensate the deviation of the clock frequency between the driving chip and the main control chip based on an algorithm, the consistency of time response between the driving chips is ensured, and on the basis, a phase-locked loop (PLL) is not required to be additionally arranged, so that the cost and the size of the chip are effectively reduced.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the invention, and that other drawings can be obtained according to these drawings without inventive faculty for a person skilled in the art.
FIG. 1 is a schematic diagram of an LED backlight system according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of an LED backlight system employing a parallel topology in accordance with an embodiment of the present invention;
FIG. 3 is a schematic diagram of a configuration of an LED backlight system employing a daisy chain topology in accordance with one embodiment of the present invention;
FIG. 4 is a schematic diagram of dimming signals of three driving chips without adopting the scheme of the embodiment of the present invention;
FIG. 5 is a flow chart of a method for processing a driving chip in an LED backlight system according to an embodiment of the invention;
FIG. 6 is a flowchart of step S21 according to an embodiment of the present invention;
FIG. 7 is a flowchart of step S212 according to an embodiment of the present invention;
FIG. 8 is a flowchart of a method for processing a main control chip in an LED backlight system according to an embodiment of the invention;
fig. 9 is a schematic diagram showing signal interaction of an LED backlight system according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The terms "first," "second," "third," "fourth" and the like in the description and in the claims and in the above drawings, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The technical scheme of the invention is described in detail below by specific examples. The following embodiments may be combined with each other, and some embodiments may not be repeated for the same or similar concepts or processes.
Referring to fig. 1 to 3, an embodiment of the present invention provides an LED backlight system, including: a driving chip 102, a main control chip 101 and an LED unit 103. The driving chip 102 is respectively connected with the main control chip 101 and the LED unit 103.
The number of the driving chips 102, the main control chip 101, and the LED units 103 may be one or more, and in a specific example, the number of the driving chips 102 connected to the same main control chip 101 is plural, and thus, the time response consistency of each driving chip 102 will affect the dimming effect, and in particular, the better the time response consistency, the better the dimming effect. In addition, the driving chip of the present specification may also be described as an LED driving chip.
The LED unit 103 includes a plurality of LED light beads, which can be controlled by the driving chip 102 after being connected in series and/or in parallel, and then can emit light under the driving of the dimming signal of the driving chip 102.
In some examples, the LED unit 103 may further include a switch, where the switch is connected to a plurality of LED beads, and the driving chip may be connected to the switch, so as to control on-off variation and/or on-off amplitude of the switch, so as to drive whether the LED beads emit light or not, and adjust light.
In some examples, the LED unit 103 may further include a current source in the LED unit 103, where the current source is connected to each LED bead, and the driving chip may also be connected to the current source, so that the LED bead may be driven to emit light or not, and dimming may be performed by controlling the current source.
The above is merely an example, and no matter what principle, circuit, or structural form of LED unit is adopted, as long as it can be driven by the driving chip to emit light, it can be used as an alternative of the embodiment of the present invention.
The driving chip can be understood as a chip which can output a dimming signal under the control of the main control chip so as to drive the LED lamp beads of the LED units to emit light.
In a specific scheme, the dimming principle of the driving chip is divided into two types: DC dimming and PWM dimming. The former adjusts the brightness of the LED lamp beads by adjusting the magnitude of the channel constant current (i.e., the current supplied to the LED lamp beads), and the latter adjusts the brightness by adjusting the duration of the opening and closing of the LED channels (i.e., the duration of the high level output by the driving chip) during a periodic period. The dimming signal according to the embodiment of the present invention may be a dimming signal under DC dimming or a dimming signal under PWM dimming.
Corresponding to the two dimming principles, for DC dimming, the dimming information sent by the main control chip to the driving chip can be information representing the corresponding current; for PWM dimming, the dimming information sent by the main control chip to the driving chip may be information representing the duration of the corresponding high level.
Furthermore, any dimming information or dimming signal according to any dimming principle may be used as an aspect of the embodiments of the present invention.
The LED backlight system of the embodiments of the present invention may employ a parallel topology (e.g., as shown in fig. 2) or a daisy chain topology (e.g., as shown in fig. 3).
The driving chip in the embodiment of the present invention may be understood as a processing method for executing the driving chip related to the present specification. The main control chip in the embodiment of the present invention may be understood as a processing method for executing the main control chip related to the present specification.
In addition, the following specific examples (e.g., specific examples of the methods) are mainly described with respect to PWM dimming schemes, and the embodiments of the present invention do not exclude the possibility of implementing the methods under DC dimming.
In order to clearly embody the advantages of the embodiments of the present invention, the following will specifically describe the reason and actual results of the poor consistency of the time response in conjunction with the waveforms shown in fig. 4 and the LED backlight system with the structure shown in fig. 2:
An oscillating circuit inside the LED driving chip generates a basic clock required by the operation of the digital circuit, and the design frequency of the clock is assumed to be 10MHz. Due to manufacturing variations, the frequency of this clock will not be exactly 10MHz even for the same lot of chips. For example, suppose a batch of 10000 LED driver chips is counted, the clock frequency may be in a range of 9.5MHz + -20%. This clock skew may result in degradation of the dimming effect if the consistency of the inter-chip time reference is not being processed.
In the case of the LED backlight system employing the structure shown in fig. 2, it is assumed that the internal oscillator frequencies of the three driving chips A, B, C are 10.5MHz, 9MHz, 11MHz, respectively. The master control chip may send a common PWM dimming parameter (i.e. dimming information) to all channels, for example, the period of PWM is set to 0x8000 (representing the duration of 0x8000 internal count periods), the high level of PMW is 0x4000, and the rising edge of PWM is offset to 0. The PWM waveforms actually output by the three driver chips are approximately as shown in fig. 4.
PWM waveforms output from different driving chips are not uniform due to the difference of the reference frequencies, and the accumulated deviation is continuously increased.
Referring to fig. 5, an embodiment of the present invention provides a method for processing a driving chip in an LED backlight system, including:
s21: obtaining deviation information;
S22: receiving dimming information sent by the main control chip;
S23: and compensating the dimming information based on the deviation information, and outputting a dimming signal based on the compensated dimming information.
The deviation information characterizes: the deviation degree and the deviation mode of the clock frequency between the driving chip and the main control chip connected with the driving chip are larger or smaller; the deviation degree can be expressed as the deviation amount per se or the ratio of the deviation amount to the clock frequency of the chip. In addition, no matter what way is adopted to enable the driving chip to acquire the deviation information, the deviation information does not deviate from the scope of the embodiment of the invention, and meanwhile, the deviation information can be stored in the acquisition process for the subsequent step S23 of calling the deviation information.
The dimming information and the dimming signal can be understood by referring to the previous description of the specification, for example: the dimming information may characterize the duration of the high level (or the duty cycle of the duration of the high level in a single period) in the dimming signal output by the driver chip.
The compensation can be understood as:
If the clock frequency of the driving chip is larger than that of the main control chip, the driving chip is: in PWM dimming, the duration of the high level in a single period can be increased by this compensation, which in other examples can also be, for example, increasing the current level in DC dimming; correspondingly, the specific amount of compensation may be adapted to change based on the degree of deviation characterized by the deviation information;
If the clock frequency of the driving chip is smaller than that of the main control chip, the driving chip is: in PWM dimming, the duration of the high level in a single cycle can be reduced by this compensation, which in other examples can also be, for example, a reduction in the current level in DC dimming; correspondingly, the specific amount of compensation may be adapted to change based on the degree of deviation characterized by the deviation information.
Therefore, in the scheme, each driving chip calculates and stores the deviation degree of the clock of the driving chip relative to the time and frequency reference of the main control chip. When each driving chip subsequently receives dimming parameters (namely dimming information) related to time base, reverse compensation is carried out according to the deviation information stored by the driving chip, so that consistency of time base among chips is realized.
In one embodiment, referring to fig. 6, step S21 may include:
s211: acquiring reference counting information;
S212: in the process of counting the reference counting information by the main control chip, counting by using a counter of the driving chip to obtain corresponding local counting information;
S213: the offset information is determined based on the local count information and the reference count information.
The reference count information can be understood as count information serving as a reference, and corresponding time length corresponding to the reference count information can be understood as reference time length for the main control chip, and specifically can be understood as: the time length of the counter of the main control chip for completing the counting process of the reference counting information is the reference time length.
In one example, the reference count information may be, for example, 0xF000 and the corresponding reference duration may be, for example, 6.144ms. The present invention is merely exemplary, and reference technical information and reference time duration are not limited thereto.
In a specific example, step S212 may include:
receiving a start command and an end command sent by the main control chip, and controlling a counter of the driving chip to count based on the start command and the end command to obtain the local count information;
wherein a time interval between the end command and the start command matches: and the counter of the main control chip counts the time length of the reference counting information.
Furthermore, in the above example, the driving chip can count (i.e. time) under the control and instruction of the main control chip, so that the actual counting result (i.e. local counting information) of the driving chip can be accurately reflected in the process of timing reference time length of the main control chip, and further, the deviation information can be calibrated by using the local counting information and the reference counting information.
In some examples, the above step S212 may be repeated a plurality of times, and further, a plurality of pieces of local count information may be obtained for one driving chip, and further, the deviation information may be calculated based on the statistical values (e.g., average values) of the plurality of pieces of local count information and the reference count information.
In a corresponding example, the deviation information is a ratio of the local count information to the reference count information, or information obtained based on the ratio (e.g., information obtained by adjusting the ratio based on experience or other circuit principles).
In addition, in a partial scheme different from the process shown in fig. 6, the driving chip may not implement steps S211 and S213, and further, in the case of executing step S212, the local count information is sent to the main control module, and further, the main control module is used to determine the deviation information; in another alternative, a reference count information may be determined by the driving chips (in this case, each driving chip needs to determine a reference count information), and then a process similar to steps S211 to S213 is implemented by using the main control module. Meanwhile, the process shown in fig. 6 is a preferred embodiment from the standpoint of both calculation efficiency and accuracy. It is also understood that the process of step S21 shown in fig. 5 is not limited to the embodiment shown in fig. 6, and can cover a wider range.
In one example, referring to fig. 7, step S212 may specifically include:
s2121: when a start command sent by the main control chip is received, starting counting by using a counter of the driving chip;
S2122: and stopping counting of the counter of the driving chip when receiving the finishing command sent by the main control chip, and obtaining the local counting information.
Other examples than the example of fig. 7 may also be to start counting after a delay after receiving a start command and/or to stop counting after a delay after receiving a finish command; for example, to compensate for delays in signal transmission.
For the above processing procedure of the driving chip, please refer to fig. 8, the embodiment of the present invention further provides a processing method of a main control chip, which includes:
s31: determining reference counting information, and broadcasting the reference counting information to a driving chip connected with the main control chip;
S32: broadcasting a start command to the driving chip, and starting counting by using a counter of the main control chip;
s33: broadcasting an ending command to the driving chip when the counter finishes counting the reference counting information;
Further, by step S33, it is possible to cause: the driving chip can control a counter of the driving chip to count based on the start command and the finish command to obtain local count information, and determine deviation information based on the local count information and the reference count information, wherein the deviation information characterizes the deviation degree and the deviation mode of clock frequency between the main control chip and the driving chip, and the deviation mode refers to larger or smaller;
s34: transmitting dimming information to the driving chip;
further, by step S34, it is possible to cause: the driving chip can compensate the dimming information based on the deviation information and output a dimming signal based on the compensated dimming information.
The technical terms, technical effects, and alternatives in the above steps can be understood by referring to the foregoing related descriptions, and are not repeated herein.
A specific scheme of the embodiment of the present invention will be described with reference to fig. 8 and 9 as follows:
The master control chip 101 may determine the reference count information first, for example, the master control chip 101 may determine that the reference clock frequency of the transmitted dimming parameter (i.e., the dimming information) is 10MHz; correspondingly, the calibration reference counter of the main control chip 101 takes a value of 0xF000 (i.e. the reference count information takes a value of 0xF 000), and the corresponding reference time length can be 6.144ms;
after determining the reference technical information, the master chip 101 may broadcast the reference count information to each of the drive chips 102 to which it is connected, e.g., the master chip 101 may broadcast notification to all of the drive chips 102 that the calibrated reference counter has a value of 0xF000;
Correspondingly, after the driver chip 102 receives the broadcast notification of the main control chip 101, reference count information may be obtained, for example, the value of the reference calibration counter is set to 0xF000;
Then, the master chip 101 may start counting (i.e. start timing of the reference time period) by using the counter of the master chip, and at the same time, may broadcast a start command to the connected driving chip 102, precisely wait for the reference time period (e.g. 6.144 ms), and after finishing counting the reference counting information (i.e. timing wait for the reference time period of e.g. 6.144 ms), the master chip 101 may broadcast an end command to the connected driving chip 102;
Correspondingly, the driving chip 102 may start counting by using the counter of the driving chip when receiving the start command, and stop counting by the counter of the driving chip when receiving the end command, so as to obtain local counting information, for example: when a start command is received, starting a local calibration counter to count according to an internal clock of the driving chip, and when a finishing command is received, stopping counting of the local calibration counter, wherein the local calibration counter value can be obtained to serve as local counting information;
after obtaining the local count information, the driver chip 102 may calculate a ratio R of the local calibration counter value (i.e. the local count information) to the reference calibration counter value (i.e. the reference count information), which may then be used as the offset information, i.e. the offset information: the offset information is determined based on the local count information and the reference count information.
Through the above procedure, a determination (also understood as calibration) of the deviation information is achieved.
In the subsequent control process, the main control chip 101 may send dimming information to the driving chip 102, and the driving chip may compensate the dimming information based on the deviation information and output a dimming signal based on the compensated dimming information. For example: after the driving chip 102 receives the dimming parameter (i.e. the dimming information), the dimming information may, for example, be PWM high level 0x4000, and when compensating the dimming information based on the dimming parameter, the local actual PWM high level 0x4000 x r may be calculated and used as the compensated dimming information; the PWM waveform may then be output based on the compensated dimming information.
The specific quantized calculation process may be, for example:
And (5) performing trial calculation. Referring to fig. 4, the frequency of the a driving chip is 10.5MHz, the frequency of the reference clock is 10MHz, the calibration reference counter takes a value of 0xF000 (i.e. the reference count information is 00xF 000), at this time, the value of the local calibration counter of the a driving chip should be 0xFC00 (i.e. the local count information is 0xFC 00), the deviation information r= xFC00/0xF 000=1.05, if the nominal PMW high level is 0x4000 (i.e. the dimming information is characterized as 0x 4000), then: the high-level PMW parameter calculation local to the a driver chip can obtain 0x4000×1.05=0x4333 (i.e. the adjusted dimming information is characterized as 0x 4333).
It can be seen that when the local clock frequency is higher than the reference clock frequency, the dimming parameter after calibration compensation becomes larger accordingly. The shortened clock period and the increased number of clock periods cancel each other out, resulting in a consistent output waveform. The case where the local clock frequency is lower than the reference clock frequency, and so on.
In addition to the above description, the digital transmission interface protocol between the master chip and the slave driver chip may be the SPI protocol, or may not be limited to the SPI protocol.
The embodiment of the invention also provides a chip which is used as a main control chip or a driving chip and can further execute the processing method of the main control chip or the processing method of the driving chip.
Embodiments of the present invention also provide a computer readable storage medium having stored thereon a computer program which when executed (e.g. by a processor or processing module) implements the methods referred to above.
In summary, in the embodiment of the invention, after the driving chip obtains the deviation information, the dimming information can be compensated, and the dimming signal is output based on the compensated dimming information, and further, for the driving chip, the deviation of the clock frequency between the driving chip and the main control chip can be compensated based on the algorithm, so that the consistency of time response between the driving chips is ensured, and on the basis, a phase-locked loop PLL (in part of examples, SYNC pins are not required to be additionally arranged), thereby effectively reducing the cost and size of the chip.
Those of ordinary skill in the art will appreciate that: all or part of the steps for implementing the method embodiments described above may be performed by hardware associated with program instructions. The foregoing program may be stored in a computer readable storage medium. The program, when executed, performs steps including the method embodiments described above; and the aforementioned storage medium includes: various media that can store program code, such as ROM, RAM, magnetic or optical disks.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.
Claims (8)
1. The processing method of the driving chip in the LED backlight system is used for processing control signals of the driving chip in the LED backlight system; the LED backlight system comprises a driving chip, a main control chip and an LED unit, wherein the main control chip and the LED unit are connected with the driving chip, and the LED backlight system is characterized by comprising:
obtaining deviation information, the deviation information characterizing: the deviation degree and the deviation mode of the clock frequency between the driving chip and the main control chip connected with the driving chip are larger or smaller;
Receiving dimming information sent by the main control chip;
Compensating the dimming information based on the deviation information, and outputting a dimming signal based on the compensated dimming information;
Wherein the acquiring the deviation information includes:
acquiring reference counting information;
in the process of counting the reference counting information by the main control chip, counting by using a counter of the driving chip to obtain corresponding local counting information;
Determining the deviation information based on the local count information and the reference count information;
In the process of counting the reference counting information by the main control chip, counting by using a counter of the driving chip to obtain corresponding local counting information, wherein the method comprises the following steps of:
receiving a start command and an end command sent by the main control chip, and controlling a counter of the driving chip to count based on the start command and the end command to obtain the local count information;
wherein a time interval between the end command and the start command matches: the time length for the counter of the main control chip to count the reference counting information;
compensating the dimming information based on the deviation information, including:
If the dimming principle of the driving chip is PWM dimming, increasing or decreasing the duration of a high level in a single period in dimming information according to the fact that the clock frequency of the driving chip is larger or smaller than that of the main control chip;
If the dimming principle of the driving chip is DC dimming, the current in the dimming information is increased or decreased according to the fact that the clock frequency of the driving chip is larger or smaller than that of the main control chip.
2. The method according to claim 1, wherein the offset information is a ratio of the local count information to the reference count information or information obtained based on the ratio.
3. The method for processing a driver chip according to claim 1, wherein,
Receiving a start command and an end command sent by the main control chip, and controlling a counter of the driving chip to count based on the start command and the end command to obtain the local count information, wherein the method comprises the following steps:
when a start command sent by the main control chip is received, starting counting by using a counter of the driving chip;
and stopping counting of the counter of the driving chip when receiving the finishing command sent by the main control chip, and obtaining the local counting information.
4. A method for processing a main control chip in an LED backlight system according to the method for processing a driving chip of any one of claims 1 to 3, comprising:
determining reference counting information, and broadcasting the reference counting information to a driving chip connected with the main control chip;
Broadcasting a start command to the driving chip, and starting counting by using a counter of the main control chip;
When the counter completes counting of the reference count information, broadcasting an ending command to the driving chip so that: the driving chip can control a counter of the driving chip to count based on the start command and the finish command to obtain local count information, and determine deviation information based on the local count information and the reference count information, wherein the deviation information characterizes the deviation degree and the deviation mode of clock frequency between the main control chip and the driving chip, and the deviation mode refers to larger or smaller;
And sending dimming information to the driving chip so that: the driving chip can compensate the dimming information based on the deviation information and output a dimming signal based on the compensated dimming information.
5. The method according to claim 4, wherein the offset information is a ratio of the local count information to the reference count information or information obtained based on the ratio.
6. An LED backlight system, comprising:
A driver chip for performing the processing method of the driver chip according to any one of claims 1 to 3; and a main control chip for executing the processing method of the main control chip according to any one of claims 4 to 5.
7. A chip for performing the steps of the method of any one of claims 1 to 3.
8. A storage medium having code stored thereon, which when executed performs the steps of the method of any of claims 1-3.
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