Multistage current adjusting system and adjusting method based on two-way transmission
By introducing bidirectional transmission and multi-stage current adjustment systems in LED display driving technology, the problem of low-gray scene brightness adjustment under unidirectional current adjustment is solved, and higher brightness uniformity and dynamic image quality are achieved.
Patent Information
- Application Number
- CN202510442053.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-09
- Publication Date
- 2025-06-20
AI Technical Summary
In the existing LED display driving technology, unidirectional current adjustment leads to poor brightness adjustment in low-gray scenarios, which are prone to problems such as color level faults, poor uniformity of low-gray, and dynamic artifacts.
A multi-stage current regulation system based on bidirectional transmission is designed to obtain the status feedback of the LED light emitting unit in real time through bidirectional data transmission between the controller and the driver chip, and use the multi-stage current regulation module for refined control.
It significantly improves the fault tolerance capability in cascaded scenarios of LED lamp beads, reduces the response delay and adjustment accuracy issues, and improves the brightness uniformity of low-grayscale scenes and the display quality of dynamic images.
Smart Images
Figure CN120183320A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of LED display, in particular to a multi-level current regulation system and method based on bidirectional transmission. Background Art
[0002] In the field of LED display driving, traditional unidirectional current regulation technologies usually adopt a single-stage current control scheme with fixed gears. Although this method can achieve basic brightness adjustment, in low-gray-scale scenarios, due to the lack of smooth transition in the stepwise change of current, it is easy to cause insufficient PWM modulation accuracy, resulting in problems such as color step faults and poor low-gray uniformity.
[0003] Existing improvement schemes attempt to improve the low-gray performance by integrating an adaptive current compensation module inside the driving chip. However, such schemes are limited by the unidirectional transmission architecture and cannot obtain the state feedback of downstream LED units in real time, resulting in significant compensation lag and inability to adapt to dynamic changes in a timely manner. At the same time, in the single-stage current regulation mode, when dealing with dynamic images, due to insufficient current switching response time and inconsistent current responses between adjacent lamp beads, it is easy to cause dynamic artifacts and color trailing phenomena. Summary of the Invention
[0004] To solve the above problems existing in the prior art, the present invention aims to design a multi-level current regulation system and method based on bidirectional transmission, which can not only improve the fault tolerance ability in the cascaded scenario of LED lamp beads, but also solve the problems of high response delay and low regulation accuracy in the prior art.
[0005] To achieve the above object, the technical solution of the present invention is as follows: A multi-level current regulation system based on bidirectional transmission, comprising a controller, n driving chips, and n LED light-emitting units; the n driving chips are connected in series in sequence, the controller is connected to the first driving chip, and each driving chip is connected to an LED light-emitting unit;
[0006] The driving chip includes a communication interface module, a status data processing module, a current regulation module, and an output current mirror module.
[0007] The communication interface module provides four bidirectional data ports, a power interface, and a data control input port, realizing redundant data transmission for the main / backup channels. When it detects an abnormal transmission in the main channel, it automatically switches to the backup channel. The four bidirectional data ports are respectively the DI port, the BI port, the DO port, and the BO port; the DI port, the BI port, the DO port, and the BO port are respectively connected to the output ports of an external controller or a superior chip. The data control input port is the LE port, which cooperates with the input of a clock signal to control instructions.
[0008] The state data processing module receives state data through the communication interface module, processes the state data and generates corresponding signals to control the brightness of the LED. The state data processing module includes a state data receiving unit, a state control unit and a data intercepting and outputting unit; the state data receiving unit receives the state data of the communication interface module and outputs the data to the data intercepting and outputting unit through the state control unit;
[0009] The current regulation module receives the data output by the data intercepting and outputting unit. The current regulation module includes a voltage regulator, a basic current regulation unit, and an output channel switch accelerator.
[0010] The output current mirror module mirrors the current generated by the current regulation module to the output pin at a certain ratio to provide a stable current for the connected LED lighting unit.
[0011] Further, the state data receiving unit includes a forward main shift register, a reverse main shift register, a forward spare shift register, a reverse spare shift register, a judgment register, a counter and a data storage unit;
[0012] The number of bits of the forward main shift register and the reverse main shift register is determined according to the number of bits N of the state data. When powered on, the DI port and the BO port are default data transmission channels;
[0013] The number of bits of the forward spare shift register and the reverse spare shift register is determined according to the number of bits N of the state data. When powered on, the BI port and the DO port are default data transmission channels;
[0014] The judgment register is used to prevent the influence between forward transmission data and reverse transmission data. The judgment register includes judgment register 1 and judgment register 2. Judgment register 1 is used to prevent the influence of reverse data transmission on forward transmission data, and judgment register 2 is used to prevent the influence of forward data transmission on reverse transmission data.
[0015] Further, the state control unit includes a control state register and a state counter;
[0016] The state register effectively stores the state data and generates corresponding instructions through the input control signal when the state is required to obtain the function of reading and writing the state register;
[0017] The number of bits of the state counter is determined according to the number of bits N of the state data. When the instruction to read the state register is obtained, the counting starts.
[0018] Further, the data intercepting and outputting unit intercepts the state data in the state register through the control signal input through the data control input port, and intercepts the current gain bit therein.
[0019] Further, the number of bits of the voltage regulator is determined according to the number of bits of the current gain bits. The voltage regulator realizes precise regulation of the amplitude of the reference voltage by dynamically configuring the equivalent resistance value of the internal resistance network corresponding to the gain adjustment bits and the ground terminal. The reference voltage combines with the externally connected set resistor to generate a multi-level adjustable operating voltage for the current regulation module, and different magnitudes of output current are generated accordingly.
[0020] Further, the basic current regulation unit receives different currents generated by the voltage regulator in combination with the externally connected resistor and mirrors and amplifies the current proportionally.
[0021] Further, the function of the output channel switch accelerator is to output current to the output current mirror module to accelerate the switching speed of the output channel.
[0022] A multi-level current regulation method based on bidirectional transmission uses a multi-level current regulation system based on bidirectional transmission to adjust the brightness of an LED, including the following steps:
[0023] Step 1: The controller sends status data and judges the 3-0 bits of register 1. If the identification is 0011, the status data is forward transmission data; if the identification is 0110, the status data is reverse transmission data; the same applies to judging register 2. Judge that register 1 and register 2 respectively detect the forward and reverse status signals to ensure bidirectional data isolation. If each driver chip works normally, go to step 2; if a certain driver chip transmits an error, go to step 4.
[0024] Step 2: Assume that it is forward transmission at this time. After the controller's forward sending end sends the status data, the status data enters the input channel of the first driver chip and is transmitted to the second driver chip through the forward output port, and at the same time returns an ACK confirmation signal to the controller.
[0025] Step 3: The second driver chip repeats the operation of the first driver chip and then transmits it to the third driver chip, and at the same time returns the ACK confirmation signal to the controller step by step; subsequent driver chips repeat the above operation until the data reaches the end driver chip.
[0026] At this time, reverse transmission is also in progress. After the controller's reverse sending end sends the status signal, the status data enters the end driver chip, and the subsequent operations are the same as those of forward transmission. The values of the status data of reverse transmission and forward transmission are the same, only the order is opposite. Go to step 6.
[0027] Step 4: If the upper-level driver chip does not receive the ACK signal from the current driver chip for three consecutive clock cycles, it means that the current driver chip has an error. Since data is transmitted simultaneously through the DI, BI, DO, and BO ports, it is set that the priority of using data is the highest for the forward main channel, followed by the forward backup channel, then the reverse main channel, and finally the reverse backup channel. If the forward main channel for data transmission has an error, the current driver chip enables the data of the forward backup shift register. If both the forward main channel and the backup channel for data transmission have errors, the current driver chip uses the reverse main channel. If the forward main channel, the forward backup channel, and the reverse main channel for data transmission all have errors, the current driver chip switches to the reverse backup data processing path and enables the data of the reverse backup shift register.
[0028] Step 5: The current driver chip sends a NAK signal to the controller, and the NAK signal carries an error type code. The error type code includes timeout, forward check failure, and reverse check failure.
[0029] Step 6: After the data transmission is completed, the driver chip selects the data with a higher priority as the valid data according to the preset channel priority. Each driver chip performs read and write operations on the status register based on the received status data and the control signal received by the LE port. When performing a read operation, the current adjustment module reads the current gain bit data, processes the data accordingly to convert it into an electric current, and the output current mirror module mirrors the current generated by the current adjustment module to the output pin at a certain ratio to control the brightness of the connected LED light-emitting unit.
[0030] Further, the working method of the driver chip includes the following steps:
[0031] A1: The bidirectional data port in the communication interface module receives the status data sent by the external controller, and then transfers the data to the status data receiving unit in the status data processing module for data continuity detection.
[0032] A2: Data continuity detection can monitor the transmission status of the main channel in real time. If the main channel is normal, go to Step 3. If it is detected that the main channel is interrupted, the system switches to the backup channel, enables the pre-stored data of the backup shift register, and go to Step 5.
[0033] A3: The LE port in the communication interface module receives the control signal sent by the external controller. If the control signal is 1 and contains 15 clock cycles, that is, the enable write signal is 1, it means that the status data is about to be written into the status register in the status control module. The controller then sends a control signal with a length of 5, that is, the write signal is 1, and the status data is written into the status register in the status control module.
[0034] A4: The data interception output module intercepts the status data X-4 bits in the status register. Wait for the controller to send a read signal with a length of 10. If the read signal is 1, the data interception output module transmits the current gain bit to the current regulation module. Go to step 6.
[0035] A5: The pre-stored data of the standby shift register is enabled, and the pre-stored data replaces the interrupted main channel data for data transmission. After waiting for the write enable signal to be 1, the write signal is 1. At this time, the status data is written to the status register in the status control module. The data interception output module intercepts the status data X-4 bits in the status register. Waiting for the controller to send a control signal with a length of 10. If the read signal is 1, the data interception output module transmits the current gain bit to the current regulation module.
[0036] A6: The voltage regulator in the current regulation module accurately controls the amplitude of the reference voltage by dynamically adjusting the equivalent resistance of the internal resistor network and the ground terminal according to the configuration of the gain adjustment bit. The reference voltage works together with the external setting resistor to generate a multi-level reference working voltage and input it to the basic current regulation unit. Based on the reference working voltage, the basic current regulation unit amplifies the reference current according to a preset ratio through the mirror amplifier circuit and outputs it to the output channel switch accelerator.
[0037] A7: The output channel switch accelerator accelerates the switching speed of the output channel and transmits the current to the output current mirror module. The output current mirror module mirrors the current generated by the current regulation module to the output pin in a certain proportion to control the brightness of the connected LED light-emitting unit.
[0038] Compared with the prior art, the present invention has the following beneficial effects:
[0039] 1. The present invention uses a two-way data transmission architecture to obtain real-time status feedback of the downstream LED light-emitting unit, and combines a multi-level current regulation mechanism to significantly reduce the compensation lag of traditional unidirectional transmission. The main / backup channel redundant design can switch the transmission path within milliseconds, and dynamically select valid data based on priority to avoid brightness jumps or data loss caused by single-channel failures. At the same time, through the multi-level current regulation module, there are 2^X levels to adjust, which can achieve refined control of current, eliminate step-type brightness changes in low grayscale scenes, solve the problems of color level faults and dynamic artifacts, and significantly improve display uniformity.
[0040] 2. The present invention ensures high reliability and display accuracy through rapid switching of redundant channels and dynamic current synchronization. When the main channel transmission is abnormal, the system immediately enables the pre-stored data of the backup channel and real-time back-transmits the status information through the reverse transmission channel to form a closed-loop control. Combined with the output channel switch accelerator, the current switching time can be shortened, and the color trailing phenomenon in dynamic images can be suppressed. In addition, the multi-level current adjustment module realizes the smooth transition and precise matching of the current through the flexible configuration of the gain bits, reduces the low gray uniformity error, and supports the stable output in high refresh rate scenarios. BRIEF DESCRIPTION OF THE DRAWINGS
[0041] Figure 1 It is a schematic diagram of the connection of multiple driving chips of the present invention.
[0042] Figure 2 It is a schematic diagram of the driving chip module of the present invention.
[0043] Figure 3 It is a schematic diagram of the internal state data transmission process of the driving chip of the present invention.
[0044] Figure 4 It is a schematic diagram of the interruption compensation timing of the present invention.
[0045] Figure 5 It is a schematic diagram of the state data structure of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0046] To make the technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings.
[0047] Data transmission operations usually converge the status data and video data into a set of data frames for transmission, which often makes the data frame bits too long and prone to transmission errors. The present invention separates the video data and status data and distinguishes the video data and status data by judging the length of the control signal input at the LE port. The focus of the present invention is the multi-level current adjustment method based on bidirectional transmission, so only the control process of status data transmission will be described in detail.
[0048] As Figure 1 shown, the LED driving system of the present invention consists of a controller, n cascaded driving chips and their corresponding n LED light-emitting units. Each driving chip includes a communication interface module, a status data processing module, a current adjustment module and an output current mirror module.
[0049] Further, the state data processing module belongs to the digital circuit part. The state data processing module includes a state data receiving module, a state control module, and a data truncating and outputting module. The state data processing module is connected to the current regulation module, and the current regulation module is connected to the output current mirror module. The current regulation module and the output current mirror module belong to the analog circuit part. The combination of the state data processing module, the current regulation module, and the output current mirror module can form a driving chip (the bandgap reference module, power-on reset module, etc. in the chip will not be introduced here one by one). Specifically, as Figure 2 shown.
[0050] Further, as Figure 3 shown. Figure 3 For Figure 2 the internal state data transmission process of the driving chip in
[0051] is detailed as follows:
[0052] Step 1: The bidirectional data port in the communication interface module receives the state data sent by the external controller, and then transmits the data to the state data receiving unit in the state data processing module for data continuity detection.
[0053] Step 2: The data continuity detection can monitor the transmission state of the main channel in real time. If the main channel is normal, go to Step 3; if it is detected that the main channel is interrupted, the system switches to the backup channel, enables the pre-stored data in the backup shift register, and goes to Step 5.
[0054] Step 3: The LE port in the communication interface module receives the control signal sent by the external controller. If the control signal is 1 and includes 15 clock cycles, that is, the enable write signal is 1, it means that the state data is about to be written into the state register in the state control module. The controller then sends a control signal with a length of 5, that is, the write signal is 1, and the state data is written into the state register in the state control module.
[0055] Step 4: The data truncating and outputting module truncates the X - 4 bits of the state data in the state register. Wait for the controller to send a control signal with a length of 10. If the read signal is 1, the data truncating and outputting module transmits the current gain bit to the current regulation module. Go to Step 6.
[0056] Step 6: The voltage regulator in the current regulation module accurately controls the amplitude of the reference voltage by dynamically adjusting the equivalent resistance value between the internal resistance network and the ground terminal according to the configuration of the gain adjustment bit. This reference voltage, in cooperation with the externally set resistor, generates a multi-level reference operating voltage and inputs it to the basic current regulation unit. Based on the reference operating voltage, the basic current regulation unit amplifies the reference current by a preset ratio through the mirror amplifier circuit and outputs it to the output channel switch accelerator.
[0057] Step 7: The output channel switch accelerator accelerates the switching speed of the output channel and transmits the current to the output current mirror module. The output current mirror module mirrors the current generated by the current regulation module to the output pin in a certain ratio to control the brightness of the connected LED lighting unit.
[0058] Furthermore, in actual operation, a single driving chip cannot control the entire LED display screen. Multiple driving chips need to be connected for data transmission to control the LED display screen. The system uses a bidirectional data channel, and the forward data and reverse data enter the driving chip internally through the DI / BO ports respectively. The data is transmitted to the next chip through the DO / BI ports to form a complete cascaded data link. Combining Figure 1 and Figure 2 , when the driving chips are cascaded for status data transmission (as Figure 4 shown), the specific steps are as follows.
[0059] Step 1: The controller sends status data and checks bits 3 - 0 of register 1. If it identifies 0011, the status data is forward transmission data; if it identifies 0110, the status data is reverse transmission data. The same applies to checking register 2. Register 1 and register 2 respectively detect the forward and reverse status signals to ensure bidirectional data isolation. If each driving chip is working properly, go to step 2; if a transmission error occurs in a certain driving chip, go to step 4.
[0060] Step 2: Assume it is forward transmission at this time. After the controller's forward sending end sends the status data, the status data enters the input channel of the first driving chip and is transmitted to the second driving chip through the forward output port, while returning an ACK confirmation signal to the controller.
[0061] Step 3: The second driving chip repeats the operation of the first driving chip, then transmits it to the third driving chip, and simultaneously returns an ACK confirmation signal to the controller level by level; subsequent driving chips repeat the above operation until the data reaches the last driving chip.
[0062] Note that reverse transmission is also in progress at this time. After the controller's reverse transmitter sends the status signal, the status data enters the end drive chip, and the subsequent operations are the same as those in forward transmission. The values of the status data in reverse transmission and forward transmission are the same, but the order is reversed. Go to step 6.
[0063] Step 4: If the previous-level drive chip has not received the ACK signal from the current drive chip for three consecutive clock cycles, it means that the current drive chip has an error. Since data is transmitted simultaneously on the DI, BI, DO, and BO ports, the priority of using data is set as follows: the forward main channel has the highest priority, followed by the forward backup channel, then the reverse main channel, and finally the reverse backup channel. If an error occurs in the forward transmission main channel, the current drive chip enables the data in the forward backup shift register; if errors occur in both the forward transmission main channel and the backup channel, the current drive chip uses the reverse transmission main channel; if errors occur in both the forward transmission main channel and the backup channel, as well as the reverse transmission main channel, the current drive chip switches to the reverse backup data processing path and enables the data in the reverse backup shift register.
[0064] Step 5: The current drive chip sends a NAK signal to the controller, and the NAK signal carries an error type code. The error type code includes timeout, forward check failure, and reverse check failure.
[0065] Step 6: When the data transmission is completed, the chip selects the data with a higher priority as the valid data according to the preset channel priority. Each drive chip performs read and write operations on the status register based on the received status data and the control signal received at the LE port. When performing a read operation, the current adjustment module reads the current gain bit data, processes the data accordingly to convert it into an electric current, and the output current mirror module mirrors the current generated by the current adjustment module to the output pin at a certain ratio to control the brightness of the connected LED lighting unit.
[0066] Further, as Figure 5 shown. Figure 5 For Figure 3-4 the status data structure in
[0067] The status data is N bits. Bits 3 to 0 of the status data are used to determine whether it is forward or reverse. Assume that 0011 is forward and 0110 is reverse; bits N to 4 of the status data can be freely set. The freely selected bits are used to set the output current gain. If bits X to 4 are set as the output current gain bits, there are 2^X levels of current adjustment. Among them, the Xth bit is the gain size selection bit, and bits X - 1 to 4 are the gain size adjustment bits. The remaining bits N to X - 1 are status reserved bits, and the status functions are not set temporarily.
[0068] The present invention is not limited to this embodiment, and any equivalent conceptions or modifications within the technical scope disclosed by the present invention shall fall within the protection scope of the present invention.
Claims
1. A multi-level current regulation system based on bidirectional transmission, characterized in that: It includes a controller, n driver chips and n LED light-emitting units; the n driver chips are connected in series in sequence, the controller is connected to the first driver chip, and each driver chip is connected to an LED light-emitting unit; The driver chip includes a communication interface module, a state data processing module, a current regulation module and an output current mirror module; The communication interface module provides four bidirectional data ports, a power supply interface and a data control input port to realize redundant data transmission of the main / backup channels. When an abnormal transmission of the main channel is detected, it automatically switches to the backup channel; the four bidirectional data ports are respectively a DI port, a BI port, a DO port and a BO port; the DI port, the BI port, the DO port and the BO port are respectively connected to the external controller or the output port of the upper chip; the data control input port is an LE port, which cooperates with the clock signal to input the control instruction; The state data processing module receives the state data through the communication interface module, processes the state data and generates a corresponding signal to control the brightness of the LED. The state data processing module includes a state data receiving unit, a state control unit and a data interception output unit; the state data receiving unit receives the state data of the communication interface module, and outputs the data to the data interception output unit via the state control unit; The current regulating module receives data output by the data interception output unit, and the current regulating module includes a voltage regulator, a basic current regulating unit, and an output channel switch accelerator; The output current mirror module mirrors the current generated by the current regulating module to the output pin in a certain ratio, and provides a stable current to the connected LED light-emitting unit.
2. The multi-level current regulation system based on bidirectional transmission according to claim 1, characterized in that: The state data receiving unit includes a forward main shift register, a reverse main shift register, a forward spare shift register and a reverse spare shift register, a judgment register, a counter and a data storage unit; The number of bits of the forward main shift register and the reverse main shift register is determined according to the number of bits N of the status data, and the DI port and the BO port are used as data transmission channels by default when power is turned on; The number of bits of the forward standby shift register and the reverse standby shift register is determined according to the number of bits N of the status data, and the BI port and the DO port are used as data transmission channels by default when power is turned on; The judgment register is used to prevent the influence between the forward transmission data and the reverse transmission data. The judgment register includes a judgment register 1 and a judgment register 2. The judgment register 1 is used to prevent the influence of the reverse data transmission on the forward transmission data, and the judgment register 2 is used to prevent the influence of the forward data transmission on the reverse transmission data.
3. The multi-level current regulation system based on bidirectional transmission according to claim 1, characterized in that: The state control unit includes a control state register and a state counter; The status register effectively stores status data, and when the status is needed, a corresponding instruction is generated through an input control signal to obtain the function of reading and writing the status register; The number of bits of the state counter is determined according to the number of bits N of the state data, and the counting starts when an instruction to read the state register is obtained.
4. The multi-level current regulation system based on bidirectional transmission according to claim 1, characterized in that: The data interception output unit intercepts the state data in the state register accordingly through the control signal inputted from the data control input port, and intercepts the current gain bit therein.
5. The multi-level current regulation system based on bidirectional transmission according to claim 1, characterized in that: The number of bits of the voltage regulator is determined according to the number of bits of the current gain bit. The voltage regulator realizes precise control of the reference voltage amplitude by dynamically configuring the equivalent resistance of the internal resistance network and the ground terminal corresponding to the gain adjustment bit; the reference voltage is combined with an external setting resistor to generate a multi-level adjustable working voltage for the current regulation module, and accordingly generates output currents of different magnitudes.
6. The multi-level current regulation system based on bidirectional transmission according to claim 1, characterized in that: The basic current regulating unit receives different currents generated by the voltage regulator in combination with an external resistor, and amplifies the currents in proportion.
7. The multi-level current regulation system based on bidirectional transmission according to claim 1, characterized in that: The function of the output channel switch accelerator is to output current to the output current mirror module, so as to accelerate the switching speed of the output channel.
8. A multi-level current regulation method based on bidirectional transmission, using any one of claims 1-7 of the multi-level current regulation system based on bidirectional transmission to adjust the brightness of an LED, comprising the following steps: Step 1: The controller sends status data and determines register 1 to identify bits 3-0. If the identification is 0011, the status data is forward transmission data; if the identification is 0110, the status data is reverse transmission data; the same applies to register 2; registers 1 and 2 are respectively detected to detect forward and reverse status signals to ensure bidirectional data isolation; if each driver chip is working properly, go to step 2; if a driver chip transmission error occurs, go to step 4; Step 2: Assuming that this is forward transmission, after the controller sends the status data to the forward transmitter, the status data enters the input channel of the first driver chip, and transmits the data to the second driver chip through the forward output port, and returns an ACK confirmation signal to the controller at the same time; Step 3: The second driver chip repeats the operation of the first driver chip, and then transmits it to the third driver chip, while returning the ACK confirmation signal to the controller step by step; the subsequent driver chips repeat the above operation until the data reaches the final driver chip; At this time, the reverse transmission is also in progress. After the reverse sending end of the controller sends the status signal, the status data enters the terminal drive chip, and the subsequent operations are the same as the forward transmission. The values of the status data of the reverse transmission and the forward transmission are the same, but the order is reversed. Go to step 6; Step 4: If the previous driver chip does not receive the ACK signal of the current driver chip for three consecutive clock cycles, it means that the current driver chip has an error; since the DI, BI, DO, and BO ports transmit data at the same time, the priority of using data is set to be the forward main channel with the highest priority, followed by the forward backup channel, then the reverse main channel, and finally the reverse backup channel; if the forward transmission main channel has an error, the current driver chip enables the data of the forward backup shift register; if both the forward transmission main channel and the backup channel have an error, the current driver chip uses the reverse transmission main channel; if both the forward transmission main channel and the backup channel and the reverse transmission main channel have an error, the current driver chip switches to the reverse backup data processing path and enables the data of the reverse backup shift register; Step 5: The current driver chip sends a NAK signal to the controller, and the NAK signal carries an error type code; the error type code includes timeout, forward check failure, and reverse check failure; Step 6: When the data transmission is completed, the driver chip selects the data with higher priority as the valid data according to the preset channel priority; each driver chip performs read and write operations on the status register according to the received status data and the control signal received by the LE port. When performing the read operation, the current regulation module reads the current gain bit data, processes the data accordingly and converts it into current. The output current mirror module mirrors the current generated by the current regulation module to the output pin at a certain ratio to control the brightness of the connected LED light-emitting unit.
9. The multi-stage current regulation method based on bidirectional transmission according to claim 8, characterized in that: The working method of the driving chip comprises the following steps: A1: The bidirectional data port in the communication interface module receives the status data sent by the external controller, and then transmits the data to the status data receiving unit in the status data processing module for data continuity detection; A2: Data continuity detection can monitor the transmission status of the main channel in real time; if the main channel is normal, go to step 3; if the main channel is interrupted, the system switches to the backup channel, enables the pre-stored data in the backup shift register, and goes to step 5; A3: The LE port in the communication interface module receives the control signal sent by the external controller. If the control signal is 1, it contains 15 clock cycles. Even if the write signal is 1, it means that the status data is about to be written into the status register in the status control module. The controller then sends a control signal with a length of 5, that is, the write signal is 1, and the status data is written into the status register in the status control module. A4: The data interception output module intercepts the status data X-4 bits in the status register; waits for the controller to send a read signal with a length of 10. If the read signal is 1, the data interception output module transmits the current gain bit to the current regulation module; go to step 6; A5: The pre-stored data of the standby shift register is enabled, and the pre-stored data replaces the interrupted main channel data for data transmission; after waiting for the write enable signal to be 1, the write signal is 1; at this time, the status data is written into the status register in the status control module; the data interception output module intercepts the status data X-4 bits in the status register; wait for the controller to send a control signal with a length of 10, if the read signal is 1, the data interception output module transmits the current gain bit to the current regulation module; A6: The voltage regulator in the current regulation module accurately controls the amplitude of the reference voltage by dynamically adjusting the equivalent resistance of the internal resistor network and the ground terminal according to the configuration of the gain adjustment bit; the reference voltage works in conjunction with the external set resistor to generate a multi-level reference working voltage and input it to the basic current regulation unit; the basic current regulation unit amplifies the reference current according to a preset ratio through the mirror amplifier circuit based on the reference working voltage and outputs it to the output channel switch accelerator; A7: The output channel switch accelerator accelerates the switching speed of the output channel and transmits the current to the output current mirror module; the output current mirror module mirrors the current generated by the current regulation module to the output pin in a certain proportion to control the brightness of the connected LED light-emitting unit.