Self-adaptive bidirectional series drive chip and LED lamp bead

Abstract

The invention belongs to the field of LED display control, and discloses a self-adaptive bidirectional series drive chip, which is characterized in that a data receiving module is used for receiving input data of DI, FDI and DO and carrying out data integrity judgment; the data bit numbers received by the DI, the FDI and the DO are sent to the state control module; the self gray value is sent to the display control module; the state control module is used for determining whether the DO and the FDI need to switch the output state or not according to the bit number and the data integrity judgment result, and determining the source of the gray value of the state control module and the source of data needing to be forwarded; the data sending module is used for forwarding data needing to be forwarded in the data received by the data receiving module; and the display control module is used for controlling the display of the LED lamp according to the gray value sent by the data receiving module. According to the technical scheme, bidirectional series connection can be supported in a self-adaptive mode, and two series connection directions can be achieved through a single-layer PCB.

Description

Technical Field

[0001] The invention belongs to the field of LED display control, and in particular relates to an adaptive bidirectional series drive chip and an LED lamp bead. Background Art

[0002] The lamp-driver integration means that the driver chip and three RGB LED lights are packaged into one lamp bead. At present, the lamp beads on the lamp board usually adopt two series connection forms: forward series connection and reverse series connection. Therefore, the packaging factory will package two different lamp beads, one for forward series connection and the other for reverse series connection.

[0003] This also brings about a prominent problem: the packaging factory has to package two different lamp beads, which will inevitably increase the complexity of stocking and patching. At the same time, the two lamp beads are very similar in appearance, and it is easy to make a mistake when patching. Summary of the invention

[0004] In order to solve the above problems, there is an urgent need for a driver chip that is compatible with and adaptively supports both forward series connection and reverse series connection, so that only one type of lamp bead needs to be packaged.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] An adaptive bidirectional series drive chip, comprising a DI pin, an FDI pin, a DO pin, a data receiving module, a state control module, a data sending module and a display control module;

[0007] The DI pin is a data input pin of the driver chip, the DO pin is a data output pin of the driver chip, and the FDI pin is a backup data input pin of the driver chip;

[0008] The data receiving module is used to receive input data from the DI pin, the FDI pin and the DO pin, and perform data integrity judgment; and send the number of bits of data received by the DI pin, the FDI pin and the DO pin to the state control module; and send its own grayscale value to the display control module;

[0009] The state control module is used to determine whether the DO pin and the FDI pin need to switch output states according to the number of bits received by each pin and the data integrity judgment result provided by the data receiving module, and to determine the source pin of the gray value of the state control module itself and the source pin of the data to be forwarded;

[0010] The data sending module is used to forward the data that needs to be forwarded among the data received by the data receiving module;

[0011] The display control module is used to control the display of the LED light according to the grayscale value sent by the data receiving module.

[0012] Preferably, the data receiving module includes a DI counter, an FDI counter and a DO counter;

[0013] The DI counter, the FDI counter and the DO counter are used to count the number of bits in the input data frame from the DI pin, the FDI pin and the DO pin respectively;

[0014] The method for the data receiving module to judge the data integrity of the input data of the DI pin, the DO pin and the FDI pin includes:

[0015] The judgment is made based on the data volume of one frame, which is A*N+C, where A is the number of bits of one chip, N is the number of chips connected in series, and C is the number of bits of the configuration register.

[0016] Preferably, the data receiving module sends three flag bits to the state control module: a DI incomplete flag, an FDI incomplete flag, and a DO incomplete flag;

[0017] When no data is received or the data is received but the number of bits is not A*N+C, the incomplete flag = 1;

[0018] When data is received and the number of bits is A*N+C, the incomplete flag = 0.

[0019] Preferably, the DI pin, the FDI pin and the DO pin are all in input state in an initial default state;

[0020] The state control module determines whether the state needs to be switched according to the input sequence of the complete data of the DI pin, the FDI pin and the DO pin;

[0021] If the DI pin has input first:

[0022] Switch the DO pin and the FDI pin to output state;

[0023] Forward the first grayscale received by the DI pin to the display control module, and send the subsequent data received by the DI pin to the data output module;

[0024] If the FDI pin has input first:

[0025] Switch the DO pin to output state;

[0026] When the main input pin is the DI pin: forward the first grayscale received by the DI pin to the display control module, and send the subsequent data received by the DI pin to the data output module; when the main input pin is the FDI pin: forward the second grayscale received by the FDI pin to the display control module, and send the subsequent data received by the FDI pin to the data output module;

[0027] When the main input pin is the DI pin and the DI pin incomplete mark = 1, notify the display control module that the grayscale of this frame is 0, and change the main input pin to the FDI pin; when the main input pin is the FDI pin and the FDI pin incomplete mark = 1, notify the display control module that the grayscale of this frame is 0, and change the main input pin to the DI pin;

[0028] If the DO pin has input first:

[0029] Switch the FDI pin to output state;

[0030] When the main input pin is the DI pin: forward the first grayscale received by the DI pin to the display control module, and send the subsequent data received by the DI pin to the data output module; when the main input pin is the DO pin: forward the second grayscale received by the DO pin to the display control module, and send the subsequent data received by the DO pin to the data output module;

[0031] When the main input pin is the DI pin and the DI pin incomplete flag = 1, the display control module is notified that the grayscale of this frame is 0, and the main input pin is changed to the DO pin; when the main input pin is the DO pin and the DO pin incomplete flag = 1, the display control module is notified that the grayscale of this frame is 0, and the main input pin is changed to the DI pin;

[0032] Preferably, the data sending module uses return-to-zero code to forward the data to be forwarded in the data receiving module;

[0033] In the return-to-zero code, a long low level indicates reset, which is used to separate data frames.

[0034] The present invention also provides an LED lamp bead, which adopts the aforementioned driving chip.

[0035] The beneficial effects of the present invention are as follows:

[0036] The present invention proposes an adaptive bidirectional series drive chip and lamp bead. The drive chip can adaptively support bidirectional series connection, and both series connection directions can be realized with a single-layer PCB. The packaging factory only needs to package one type of lamp bead, which reduces the complexity of stocking and patching, and also prevents the problem of using the wrong lamp bead. The data integrity judgment is added to avoid the instability caused by cold soldering or chip damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative labor:

[0038] Figure 1 This is a schematic diagram of the lamp driver being packaged into a lamp bead;

[0039] Figure 2 It is a modular schematic diagram of the control logic of existing lamp beads;

[0040] Figure 3 A schematic diagram of the series connection method used by the lamp beads on the existing lamp board;

[0041] Figure 4 A schematic diagram of the forward series connection method used by the lamp beads on the existing lamp board;

[0042] Figure 5 A schematic diagram of the reverse series connection method used by the lamp beads on the existing lamp board;

[0043] Figure 6 A schematic diagram of the reverse series connection + rotating lamp bead method used by the lamp beads on the existing lamp board;

[0044] Figure 7 A schematic diagram of the connection between the driver chips of the rotating lamp beads and the non-rotating lamp beads used in the existing lamp board;

[0045] Figure 8 A modular schematic diagram of the adaptive bidirectional series drive chip proposed in this application;

[0046] Fig. 9 This is a schematic diagram of the return-to-zero code used by the data sending module in this application;

[0047] Fig.10 This is a schematic diagram of the state control mechanism of this application;

[0048] Fig.11 This is a schematic diagram of the lamp bead packaging of this application;

[0049] Fig.12This is a schematic diagram of the forward series connection for practical application of the present application.

[0050] Fig.13 This is a schematic diagram of reverse series connection for practical application of the present application. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] The lamp driver is integrated, which means that the driver chip and three RGB LED lamps are packaged into one lamp bead. Figure 1 As shown, VDD and GND are power and ground, NC is an unused pin, DI is the data input pin, DO is the data output pin, and FDI is the backup data input pin. When a certain lamp bead is damaged, the lamp bead behind the damaged lamp bead can obtain data from the lamp bead in front of the damaged lamp bead through FDI. The control method of the lamp bead is usually: if DI has input (regardless of whether FDI has input): use the data input by DI as its own grayscale, and output data from DO. If DI has no input: use the data input by FDI as its own grayscale, and output data from DO. If neither DI nor FDI has input: sleep. Its functional modularization is shown as follows Figure 2 shown.

[0053] The lamp beads on the lamp board are usually connected in series, such as Figure 3 As shown, if there are N chips in series, the controller will send the grayscale of N chips per frame. One chip can be 48 bits (16 bits for RGB), 24 bits (8 bits for RGB), or other bit numbers. If DI has data, save the grayscale of the first chip received by DI, and send the other grayscales received by DI to the following chips through DO. If DI has no data but FDI has data, discard the grayscale of the first chip received by FDI, save the grayscale of the second chip received by FDI, and send the other grayscales received by FDI to the following chips through DO.

[0054] The specific series connection method is divided into forward series connection, such as Figure 4 As shown, and reverse series connection, such as Figure 5As shown. Some LED display screens are limited to single-layer PCBs, such as glass screens, crystal film screens, etc. Forward series connection can be achieved on a single-layer PCB. On a single-layer PCB, some wires need to pass through the middle of two pads. The pad spacing of many lamp beads is only 10 mil or even smaller. Generally, the spacing between the trace and the edge of the pad on both sides is required to be 10 mil to prevent short circuits, so single-layer PCBs cannot be reversely connected in series.

[0055] Another method is to rotate the lamp beads 180 degrees and then connect them in reverse series. Figure 6 As shown in the figure, this can support a single-layer PCB. However, the rotation of the lamp beads will cause another problem: the color of the rotated lamp beads and the non-rotated lamp beads will be slightly different from the user. In order to make the color of the rotated and non-rotated lamp beads consistent, as shown in the figure, the rotation of the lamp beads will cause a slight difference in the color of the rotated and non-rotated lamp beads. Figure 7 As shown in the figure, Figure a shows the non-rotated lamp bead, which is used for forward series connection, and Figure b shows the rotated lamp bead, which is used for reverse series connection. In Figure b, by adjusting the sequence of LED lights connected to outR / outG / outB, the colors of the rotated and non-rotated lamp beads are consistent. The outR / outG / outB of the driver chip are equivalent pins, and the color of the LED light can be changed.

[0056] Therefore, the packaging factory has to package two different lamp beads, which increases the complexity of stocking and patching. At the same time, the two lamp beads are very similar in appearance, and it is easy to make a mistake when patching.

[0057] Embodiment 1

[0058] This application proposes an adaptive bidirectional series drive chip, and its modular schematic diagram is as follows: Figure 8As shown, it includes a DI pin, an FDI pin, a DO pin, a data receiving module, a state control module, a data sending module and a display control module. Among them, the DI pin is the data input pin of the driver chip, the DO pin is the data output pin of the driver chip, and the FDI pin is the backup data input pin of the driver chip. The data receiving module is used to receive the input data of the DI pin, the FDI pin and the DO pin, count the input data, and make data integrity judgments. And, send the bit number of the DI pin, the FDI pin and the DO pin to the state control module. And, from the input data, send its own grayscale value to the display control module. The state control module is used to obtain the data volume and data integrity mark input by the DI pin / FDI pin / DO pin from the data receiving module, and determine whether the DO pin and the FDI pin need to switch the output state according to the data integrity judgment result of the data receiving module. And, determine which grayscale value is its own grayscale value. The data sending module is used to forward the data that needs to be forwarded in the data receiving module to the output pin to send data according to the communication protocol for sending data. The display control module is used to control the waveform of outR / outG / outB and light up the LED lamp according to the grayscale value sent by the data receiving module.

[0059] The following is a detailed description of the structure and specific functional implementation of the main functional modules:

[0060] Data sending module

[0061] The communication protocol used by the data transmission module is return-to-zero code, such as Fig. 9 As shown in Figure 1, in the return-to-zero code, a long low level indicates reset, which is used to separate the data frame, as shown in Figure a. The data frame contains the grayscale values ​​of many chips and some register configuration values, as shown in Figure b. For example: a chip has 48-bit grayscale, the register configuration is 15 bits, and when 10 chips are connected in series, one frame of data = 495 bits. The number of bits of the grayscale value of a chip is not fixed, it can be 48 bits (16 bits for RGB), 24 bits (8 bits for RGB), or other values.

[0062] Data receiving module

[0063] In the production process of light strings, cold soldering may occur, which may cause problems when customers use the light string even though the light string is tested normally in the factory. Therefore, it is necessary to automatically determine the data integrity and automatically switch the data source when the data is incomplete. For example, when the data input by the DI pin is incomplete, the data input by the FDI pin can be used.

[0064] The data receiving module is provided with a DI pin counter, an FDI pin counter and a DO pin counter, which are used to count the number of bits in the input data frame from the DI pin, the FDI pin and the DO pin respectively. The number of bits in this frame is counted from one reset state to the next reset state.

[0065] The data receiving module judges the data integrity of the input data of the DI pin, DO pin and FDI pin by judging according to the data volume of one frame. Specifically, the data volume of one frame is expressed as A*N+C, where A is the number of bits of one chip, N is the number of chips in series, and C is the number of bits of the configuration register. The complete data volume should be: A+C, 2A+C, 3A+C, and so on.

[0066] For example: 48N+15A=48, when C=15, the complete data volume should be 63 bits, 111 bits, 159 bits, and so on.

[0067] The data receiving module sends three flag bits to the status control module: DI pin incomplete flag, FDI pin incomplete flag, and DO pin incomplete flag.

[0068] When no data is received or data is received but the bit number is not A*N+C, the incomplete flag = 1. When data is received and the bit number is A*N+C, the incomplete flag = 0.

[0069] In tandem applications, the impact of incomplete data is significant:

[0070] Treating incomplete data as its own grayscale value will cause the self-lit LED light to flicker.

[0071] Forwarding incomplete data to other chips will cause the entire light strip to flicker.

[0072] State control module

[0073] According to the number of bits received by each pin and the data integrity judgment result provided by the data receiving module, determine whether the DO pin and the FDI pin need to switch the output state, and determine the source pin of the grayscale value of the state control module itself and the source pin of the data to be forwarded.

[0074] Specific:

[0075] After the chip is powered on, the default DI pin / FDI pin / DO pin are all in input state, and then enter different states according to which DI pin / FDI pin / DO pin has input data first, such as Fig.10 As shown:

[0076] (1) DI pin receives input first: DI pin receives data before FDI pin and DO pin

[0077] (2) FDI pin has input first: FDI pin receives data before DI pin and DO pin

[0078] (3) DO pin has input first: DO pin receives data before DI pin and FDI pin

[0079] If there is no input to any of the three pins, the current grayscale will be maintained and no data will be output.

[0080] Although all three pins can be in input state, only the grayscale value received by one pin will be sent to the display module, and this pin is called the main input pin. In the initial default state, the main input pin is the DI pin.

[0081] (1) DI pin has input first

[0082] Switch the DO pin and the FDI pin to output state.

[0083] Forward the first grayscale received by the DI pin to the display control module, and send the subsequent data received by the DI pin to the data output module;

[0084] (2) FDI pin has input first

[0085] Switch the DO pin to output state.

[0086] When the main input pin, that is, the source pin of its own grayscale value, is the DI pin: forward the first grayscale received by the DI pin to the display control module, and send the subsequent data received by the DI pin to the data output module; when the main input pin is the FDI pin: forward the second grayscale received by the FDI pin to the display control module, and send the subsequent data received by the FDI pin to the data output module;

[0087] When the main input pin is the DI pin and the DI pin incomplete mark = 1, notify the display control module that the grayscale of this frame is 0, and change the main input pin to the FDI pin; when the main input pin is the FDI pin and the FDI pin incomplete mark = 1, notify the display control module that the grayscale of this frame is 0, and change the main input pin to the DI pin;

[0088] (3) DO pin has input first

[0089] Switch the FDI pin to output state.

[0090] When the main input pin is the DI pin: forward the first grayscale received by the DI pin to the display control module, and send the subsequent data received by the DI pin to the data output module; when the main input pin is the DO pin: forward the second grayscale received by the DO pin to the display control module, and send the subsequent data received by the DO pin to the data output module;

[0091] When the main input pin is the DI pin and the DI pin incomplete flag = 1, the display control module is notified that the grayscale of this frame is 0, and the main input pin is changed to the DO pin; when the main input pin is the DO pin and the DO pin incomplete flag = 1, the display control module is notified that the grayscale of this frame is 0, and the main input pin is changed to the DI pin;

[0092] The schematic diagram of the LED lamp bead packaged with the driver chip of the present application is as follows: Fig.11 As shown, VDD and GND are power supply and ground, NC is an unused pin, DI pin is a data input pin, DO pin is a data output pin or a backup data input pin, and FDI pin is a data output pin or a backup data input pin.

[0093] Using the driver chip of this application, only one packaging method is needed, and the actual application is shown as follows Fig.12 As shown, the lamp beads are connected in series in the forward direction: the DI pin and the FDI pin have input, and the DO pin outputs. Fig.13 As shown, the lamp beads are connected in reverse series: the DI pin and the DO pin have input, and the FDI pin outputs. Both the forward and reverse directions can be realized on a single-layer PCB, so there is no need to package two types of lamp beads.

[0094] By adopting the technical solution of this application, the packaging factory only needs to package one type of LED lamp bead, which reduces the complexity of stocking and patching, and also prevents the problem of using the wrong lamp bead. Both series directions can be implemented with a single-layer PCB. The data integrity judgment is added to avoid the instability caused by cold soldering or chip damage.

[0095] The embodiments described above are only descriptions of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. An adaptive bidirectional series driver chip, characterized in that: It includes DI pin, FDI pin, DO pin, data receiving module, state control module, data sending module and display control module; The DI pin is a data input pin of the driver chip, the DO pin is a data output pin of the driver chip, and the FDI pin is a backup data input pin of the driver chip; The data receiving module is used to receive input data from the DI pin, the FDI pin and the DO pin, and perform data integrity judgment; And, sending the data bit number received by the DI pin, the FDI pin and the DO pin to the state control module; and sending its own grayscale value to the display control module; The state control module is used to determine whether the DO pin and the FDI pin need to switch output states according to the number of bits received by each pin and the data integrity judgment result provided by the data receiving module, and to determine the source pin of the gray value of the state control module itself and the source pin of the data to be forwarded; The data sending module is used to forward the data that needs to be forwarded among the data received by the data receiving module; The display control module is used to control the display of the LED light according to the grayscale value sent by the data receiving module.

2. The driver chip according to claim 1, characterized in that: The data receiving module includes a DI counter, an FDI counter and a DO counter; The DI counter, the FDI counter and the DO counter are used to count the number of bits in the input data frame from the DI pin, the FDI pin and the DO pin respectively; The method for the data receiving module to judge the data integrity of the input data of the DI pin, the DO pin and the FDI pin includes: The judgment is made based on the data volume of one frame, which is A*N+C, where A is the number of bits of one chip, N is the number of chips connected in series, and C is the number of bits of the configuration register.

3. The driver chip according to claim 2, characterized in that: The data receiving module sends three flag bits to the state control module: a DI incomplete flag, an FDI incomplete flag, and a DO incomplete flag; When no data is received or the data is received but the number of bits is not A*N+C, the incomplete flag = 1; When data is received and the number of bits is A*N+C, the incomplete flag = 0.

4. The driver chip according to claim 3, characterized in that: The DI pin, the FDI pin and the DO pin are all in input state in the initial default state; The state control module determines whether the state needs to be switched according to the input sequence of the complete data of the DI pin, the FDI pin and the DO pin; If the DI pin has input first: Switch the DO pin and the FDI pin to output state; Forward the first grayscale received by the DI pin to the display control module, and send the subsequent data received by the DI pin to the data output module; If the FDI pin has input first: Switch the DO pin to output state; When the main input pin is the DI pin: forward the first grayscale received by the DI pin to the display control module, and send the subsequent data received by the DI pin to the data output module; when the main input pin is the FDI pin: forward the second grayscale received by the FDI pin to the display control module, and send the subsequent data received by the FDI pin to the data output module; When the main input pin is the DI pin and the DI pin incomplete mark = 1, notify the display control module that the grayscale of this frame is 0, and change the main input pin to the FDI pin; when the main input pin is the FDI pin and the FDI pin incomplete mark = 1, notify the display control module that the grayscale of this frame is 0, and change the main input pin to the DI pin; If the DO pin has input first: Switch the FDI pin to output state; When the main input pin is the DI pin: forward the first grayscale received by the DI pin to the display control module, and send the subsequent data received by the DI pin to the data output module; when the main input pin is the DO pin: forward the second grayscale received by the DO pin to the display control module, and send the subsequent data received by the DO pin to the data output module; When the main input pin is the DI pin and the DI pin incomplete mark = 1, notify the display control module that the grayscale of this frame is 0, and change the main input pin to the DO pin; when the main input pin is the DO pin and the DO pin incomplete mark = 1, notify the display control module that the grayscale of this frame is 0, and change the main input pin to the DI pin.

5. The driver chip according to claim 1, characterized in that: The data sending module uses return-to-zero code to forward the data that needs to be forwarded in the data receiving module; In the return-to-zero code, a long low level indicates reset, which is used to separate data frames.

6. An LED lamp bead, wherein the lamp bead adopts the driving chip according to any one of claims 1 to 5.

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