CN117059011A - LED driving circuit and connection method thereof - Google Patents
LED driving circuit and connection method thereof Download PDFInfo
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- CN117059011A CN117059011A CN202211251616.7A CN202211251616A CN117059011A CN 117059011 A CN117059011 A CN 117059011A CN 202211251616 A CN202211251616 A CN 202211251616A CN 117059011 A CN117059011 A CN 117059011A
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- 238000000034 method Methods 0.000 title claims abstract description 22
- 230000005540 biological transmission Effects 0.000 abstract description 11
- 238000010586 diagram Methods 0.000 description 17
- 239000011324 bead Substances 0.000 description 8
- 238000004806 packaging method and process Methods 0.000 description 4
- 230000008054 signal transmission Effects 0.000 description 3
- 238000009826 distribution Methods 0.000 description 2
- 238000012512 characterization method Methods 0.000 description 1
- 230000005670 electromagnetic radiation Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
Classifications
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
- Control Of El Displays (AREA)
Abstract
The LED driving circuit comprises a serial signal interception module, a serial signal decoding module, a display control module and a clock oscillator, wherein a signal input port inputs a display control signal, a signal output port sends the display control signal to the next stage, an address input port receives address setting, and an LED driving port is used for driving an LED light emitting device. In the process of display control data transmission, display control data is received from a signal input port, a serial signal interception module intercepts N times of N groups of data required by the serial signal interception module for the input serial display control data, and then the rest display control data is directly sent to a next-stage driving circuit through a signal output port, wherein N is a natural number greater than or equal to 2. The N LED driving circuits are respectively connected with the corresponding LED light emitting devices, the signal input ports of the N LED driving circuits are connected together and then connected with serial signals transmitted by the upper-stage circuit, and the output ports of the N LED driving circuits are connected together and serve as input signals of the lower-stage circuit.
Description
Technical field:
the invention relates to the technical field of LED display, in particular to a driving circuit for driving an LED display device and a connection method thereof.
The background technology is as follows:
at present, in the technical methods for transmitting display data of outdoor and indoor LED driving circuits, two common methods are:
in the method 1, the international standard DMX512 protocol is adopted for cascade transmission, each stage of driving circuit intercepts serial display data required by the driving circuit and directly transmits the rest of serial display data to the next stage of circuit, and the cascade mode can cause that the pulse width of effective characterization data information in the data transmission process is narrowed or widened step by step, so that the pulse width is insufficient for characterizing carried information when the cascade stage number is more.
In the method 2, the driving circuit receives serial data and then performs local decoding, the input data is rebuilt and forwarded by using the local clock resource of the driving circuit, the forwarded data waveform is the waveform rebuilt by using the local clock after the input data intercepts the data locally required by the input data, and the method can avoid the problem of waveform deformation in the serial display data transmission process. Patent CN101707042B provides an implementation of this method.
In the above two methods, there is a reliability problem, all driving circuits are in cascade connection state, in the cascade connection driving circuits, as long as there is a failure of one-stage driving circuit, the subsequent display data cannot be transmitted, the subsequent driving circuit cannot control the LED display device to perform normal display, especially in method 2, the input signal is decoded first, and then the local clock code is used for forwarding, thus providing higher requirements for the reliability of the system and the stability of the clock.
The invention comprises the following steps:
the invention aims to provide an LED driving circuit and a connection method thereof, which can perform display control data transmission and display with high reliability, aiming at the reliability problem and waveform deformation problem in the technical method of the display data transmission of the current LED driving circuit.
In order to achieve the above object, the present invention provides a solution that:
the LED driving circuit comprises a serial signal interception module, a serial signal decoding module, a display control module and a clock oscillator, wherein a signal input port inputs a display control signal, a signal output port sends the display control signal to the next stage, an address input port receives address setting, and an LED driving port is used for driving an LED light emitting device. In the process of display control data transmission, a signal input port receives display control data, a serial signal interception module intercepts N times of N groups of data required by the serial signal interception module for the serial display control data input from the signal input port, and then the rest display control data is directly sent to a next-stage driving circuit through a signal output port, wherein N is a natural number greater than or equal to 2. And in the intercepted N groups of data, the LED driving circuit selects one group of data in the N groups of data to be used for display control of the LED driving circuit according to the setting of the address input port.
When a plurality of LED driving circuits are connected, N LED driving circuits are respectively connected with corresponding LED light emitting devices, signal input ports of the N LED driving circuits are connected together and then connected with serial signals transmitted by a previous stage circuit, and output ports of the N LED driving circuits are connected together and used as input signals of a next stage circuit. The address input end of each LED driving circuit is provided with an independent address according to respective requirements, so that one group of intercepted N groups of data is selected for display control.
Because the data waveforms output by the signal output ports of the N driving circuits are the same, the N driving circuits can be connected in parallel to serve as input signals of the next stage circuit, when one LED driving circuit fails and can not send signals to the next stage circuit, the other N-1 LED driving circuits can still send correct signals to the next stage circuit, so that only the failed LED driving circuit displays the occurrence of problems, and the other LED driving circuits can still work normally, thereby improving the reliability of the whole system. Meanwhile, the connection method reduces the cascade stage number of the LED drive circuit, so that the waveform deformation problem caused by signal cascade transmission is solved, and the signal transmission waveform deformation problem is also solved while the reliability is improved.
Description of the drawings:
the invention is further described below with reference to the drawings and embodiments:
FIG. 1 is a functional block diagram of an LED driver circuit;
FIG. 2 is a schematic diagram of signal encoding;
FIG. 3 is a schematic diagram of the operation of the serial signal intercept module;
FIG. 4 is a schematic diagram of LED drive circuit connections;
FIG. 5 is a schematic diagram of the various stages of signals during the signal transmission of the LED driving circuit;
FIG. 6 is a schematic diagram of display data frame and control data frame signals;
FIG. 7 is a schematic diagram of an LED driver circuit and light emitting element integrated into a 4-pin device;
FIG. 8 is a diagram of two different pin distributions of a 4-pin device formed by the LED driver circuit and the light emitting element;
FIG. 9 is a schematic diagram of a connection of a LED driver circuit and a light emitting element packaged 4-pin device;
in the figure, an LED driving circuit, a red light emitting device, a green light emitting device, a blue light emitting device, a serial signal interception module, a serial signal decoding module, a display control module and a clock oscillator are respectively arranged in sequence, wherein the LED driving circuit, the red light emitting device, the green light emitting device, the blue light emitting device, the serial signal interception module, the serial signal decoding module, the display control module and the clock oscillator are respectively arranged in sequence.
The specific embodiment is as follows:
fig. 1 is a functional block diagram of an LED driving circuit (1) according to an exemplary embodiment of the present invention, where a serial signal interception module (11) is configured to intercept N times of serial data required by itself, in this embodiment, n=4 is selected, display data required by each LED driving circuit (1) is 48 bits of data, respectively 16 bits of red gray data, 16 bits of green gray data, and 16 bits of blue gray data, and the serial signal interception module (11) is configured to intercept data sent from a data input port SDI, and output the remaining serial data to a next stage through a data output port SDO after intercepting 4 times of data required by itself, that is, 192 bits of data. The serial signal decoding module (12) selects one group of data in the intercepted 4 groups of 48-bit data to decode according to the level setting of the address input ports A0 and A1, and sends the decoding result to the display control module (13). The display control module (13) carries OUT PWM pulse width modulation on the LED driving ports OUT_R, OUT_G and OUT_B according to the sent 48bit display data, so as to control the luminous brightness of an external LED luminous device. The clock oscillator (14) provides a clock signal source for the whole LED driving circuit (1).
Fig. 2 is a schematic diagram of signal encoding transmitted on the data input port SDI and the data output port SDO, in this embodiment, data 0 and 1 are represented by signals with a period T of 2us, where the high level width of data 0 is typically t×1/4, i.e. a high level time of 0.5 us; the typical value of the high level width of data1 is T3/4, i.e. a high level time of 1.5 us. The reset signal is a low level signal having a width greater than T x K, and the width of the low level is selected to be greater than T x 8, i.e., greater than 16us, in order to make the signal expression more stable. The high-low level time of the data input port SDI signal is respectively counted by using a counter, and the state of the signal can be judged according to the counting result. In this embodiment, the clock frequency of the clock oscillator (14) is 4MHz, and the serial signal decoding module (12) determines the signal sent from the data input port SDI by the following method: if the continuous count value in the low level state is greater than or equal to 40, it can be determined that the reset signal is sent from the current data input port SDI, and by determining the continuous count value in the high level state, it can be determined whether the signal is 0 or 1, if the continuous count value in the high level state is greater than 4, it can be determined as data1, otherwise it is determined as data 0.
Fig. 3 is a schematic diagram of the operation of the serial signal intercept module (11), in which SDI is a data input port, SDO is a data output port, counter_ge_192 is a counting result of an internal COUNTER taking a lower edge of a signal at the SDI input end as a trigger edge, the counter_ge_192 is changed to a state 0 after receiving a reset signal on the SDI, and is changed from the state 0 to the state 1 after receiving a lower edge of a signal of 192 data 0 or 1, when the signal counter_ge_192 is in the state 0, the and gate U100 is closed, the SDO is maintained at a low level, and when the counter_ge_192 is in the state 1, the state of the SDO end is equal to the input signal at the SDI end. The SDO end output waveform is a waveform obtained by intercepting 192 data of an SDI signal. In the figure, a resistor R1 is used to limit the output drive current of the data output port SDO.
Fig. 4 is a connection schematic diagram of the LED driving circuit (1) in the present embodiment in use, the signal input terminals SDI of the LED driving circuits U1, U2, U3, and U4 are connected together to obtain signals from the input terminal DATA1, and the signal output terminals SDO of the U1, U2, U3, and U4 are connected together to generate DATA2 signals as input signals of the next group of LED driving circuits. The signal inputs (SDIs) of the LED drive circuits U5, U6, U7, U8 are connected together and to the DATA2 signal, the signal outputs SDOs of U5, U6, U7, U8 are connected together to generate the DATA3 signal as the input signal for the next set of drive circuits, and so on. In this embodiment, the connection states of the address input ends A0 and A1 of the U1, U2, U3 and U4 are GND, VDD GND, GND VDD and VDD respectively, which are four different connections used for indicating to the LED driving circuits U1, U2, U3 and U4, the 1 st, 2 nd, 3 rd and 4 th sets of display data in the intercepted 4 sets of display data are respectively used for the display control module (13) in the U1, U2, U3 and U4, and the 4 sets of data intercepted in the first stage are completely displayed through the U1, U2, U3 and U4 respectively, and the data display of other stages is the same as that of the first stage. In the working process, one LED driving circuit in U1, U2, U3 and U4 fails and can not output signals, and the rest three LED driving circuits can still send correct signals to the next-stage circuit, so that the display failure is limited to one failed LED driving circuit, and other LED driving circuits are not affected.
Fig. 5 is a schematic diagram of each stage of signals in the signal transmission process of the plurality of LED driving circuits (1), and it can be seen from the figure that DATA2 is a waveform obtained by cutting out 192-bit DATA signals, namely, 4-group 48-bit DATA signals, by DATA1, and DATA3 is a waveform obtained by cutting out 192-bit DATA signals, namely, 4-group 48-bit DATA signals, by DATA 2.
The foregoing is a basic scheme of the embodiment of the present invention, and in practical implementation, the following aspects may be further improved, which further improves the advantages brought by the present invention.
In the signal coding, a control signal coding can be added, and the control signal coding is used for indicating the following frame data as control data. Fig. 6 is a schematic diagram showing data frame and control data frame signals encoded with a high level greater than T x K, such as a high level greater than 16us, as a control signal. The data content of the control data frame transmission can be used for setting the output current of the LED drive ports of each LED drive circuit (1), and can also be used for adjusting the threshold level for judging the level of the signal input ports, so that the waveform deformation problem of cascade transmission is solved. The control data frame may correspond to one LED driving circuit (1) with one set of control data, or may correspond to a plurality of LED driving circuits (1) with one set of control data.
The setting of the address input port can be directly set in the integrated circuit chip when the integrated circuit chip is manufactured, the address input port bonding pad can be connected in the integrated circuit package by a wire when the integrated circuit chip is packaged, and the address input port can be connected to an external pin of the integrated circuit package when the integrated circuit chip is packaged and connected to a printed circuit board. In addition, to increase flexibility, programmable cells such as fuse cells may be placed directly on the integrated circuit chip, with address input ports being set directly by programming. In addition, in order to save the pin number of the address input port, the address input port may be designed to recognize not only the ground line and VDD connection states but also other connection states such as floating.
When the display control module (13) realizes gray scale representation, 16-bit gray scale data can be divided into two parts, for example, high-order 10-bit gray scale data is realized by adopting a common PWM mode, and low-order 6-bit gray scale data is used for determining whether to insert a conducting state with a conducting time of 1/1024 of the PWM signal period behind the high-order 10-bit PWM signal period; the gray scale expression of the low-order 6-bit gray scale data is completed through 64 insertion decisions; the gray scale can be expressed by adopting the method, and the high refresh rate and the high gray scale can be simultaneously achieved.
In addition, the LED driving circuit (1) can be sealed together with the light-emitting element to form a light-emitting lamp bead with the built-in driving circuit, and in some high-voltage application occasions, a zener diode can be placed in the sealed package body to clamp the voltage between VDD and GND. Fig. 7 is a schematic diagram of a 4-pin device formed by integrating the LED driving circuit (1) and the light emitting element, in which SDI is a signal input port, SDO is a signal output port, and VDD of the LED driving circuit (1) is connected to the positive electrode of the light emitting element. Fig. 8 shows two different pin distributions of the LED driving circuit (1) and the light emitting element combined into a 4-pin device, wherein pin 1 of the package form a is a power supply port VDD, pin 2 is a signal input port SDI, pin 3 is a signal output port SDO, pin 4 is a ground line port GND, pin 1 of the package form B is a power supply port VDD, pin 2 is a signal output port SDO, pin 3 is a signal input port SDI, and pin 4 is a ground line port GND. Fig. 9 is a schematic connection diagram of a 4-pin device sealed by the LED driving circuit (1) and the light emitting element, wherein all the light emitting beads of the built-in driving circuit can be connected in parallel through 4 parallel wires, and the SDI ports of the bead group in the packaging form a can be sent to the SDI ports of the bead group in the packaging form B by cutting off the connecting wires between the SDIs and the SDOs of the adjacent two bead groups, and the SDO ports of the bead group in the packaging form B can be sent to the SDI ports of the bead group in the next packaging form a, so that a light string is formed repeatedly in sequence; the address input ports of the four LED driving circuits (1) of each group of lamp beads are respectively set to be an address 1, an address 2, an address 3 and an address 4 through internal connection.
In practical application, the period and the duty ratio of the signal coding can be adjusted according to the requirements of electromagnetic radiation, data transmission speed and the like. The signal coding mode adopted in the embodiment is pulse width coding, and in practical application, a coding mode of an international standard DMX512 signal protocol can also be adopted.
Claims (6)
1. The utility model provides a LED drive circuit, contains serial signal interception module, signal input port, signal output port, LED drive port, its characterized in that: the serial signal intercepting module intercepts N times of N groups of data required by the serial display data input from the signal input port, one group of N groups of data is used for display driving of the serial display data, and the intercepted residual serial display data is sent to a next-stage circuit through the signal output port, wherein N is a natural number greater than or equal to 2.
2. The LED driving circuit according to claim 1, wherein: the LED driving circuit is also internally provided with a serial signal decoding module, a display control module and a clock oscillator.
3. The LED driving circuit according to claim 2, wherein: the LED driving circuit further comprises an address input port, and selects one of the intercepted N groups of data to be used for display driving of the LED driving circuit according to the level setting of the address input port, wherein N is a natural number greater than or equal to 2.
4. The LED driving circuit of claim 3, wherein: the LED driver circuit is designed as an integrated circuit with one data input port, one data output port, 3 LED driver ports, 2 address input ports.
5. A connection method of an LED driving circuit is characterized in that: n signal input ports of the LED driving circuits comprising a serial signal interception module, a signal input port, a signal output port and an LED driving port are connected together to acquire serial data from a signal source, and meanwhile, the signal output ports of the N LED driving circuits are connected together to serve as the signal source of the next group of LED driving circuits; for serial display data input by a signal input port, a serial signal interception module intercepts N times of N groups of data required by the serial display data, one group of the N groups of data is used for display driving of the serial display data, and the intercepted residual serial display data is sent out through a signal output port; wherein N is a natural number of 2 or more.
6. The method of connecting an LED driving circuit according to claim 5, wherein: each LED driving circuit is provided with an address input port, and each LED driving circuit selects one of the intercepted N groups of data for display driving according to the level setting of the respective address input port, wherein N is a natural number greater than or equal to 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211251616.7A CN117059011A (en) | 2022-10-13 | 2022-10-13 | LED driving circuit and connection method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211251616.7A CN117059011A (en) | 2022-10-13 | 2022-10-13 | LED driving circuit and connection method thereof |
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| Publication Number | Publication Date |
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| CN117059011A true CN117059011A (en) | 2023-11-14 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202211251616.7A Pending CN117059011A (en) | 2022-10-13 | 2022-10-13 | LED driving circuit and connection method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117746802A (en) * | 2023-11-27 | 2024-03-22 | 北京显芯科技有限公司 | Method for controlling instruction transmission, dimmer and backlight unit |
-
2022
- 2022-10-13 CN CN202211251616.7A patent/CN117059011A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117746802A (en) * | 2023-11-27 | 2024-03-22 | 北京显芯科技有限公司 | Method for controlling instruction transmission, dimmer and backlight unit |
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