CN107548185A - A kind of single wire transmission technology of accurate control LED drive chip output current - Google Patents
A kind of single wire transmission technology of accurate control LED drive chip output current Download PDFInfo
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- CN107548185A CN107548185A CN201610467416.3A CN201610467416A CN107548185A CN 107548185 A CN107548185 A CN 107548185A CN 201610467416 A CN201610467416 A CN 201610467416A CN 107548185 A CN107548185 A CN 107548185A
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- led drive
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- drive chip
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- output current
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
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Abstract
The invention discloses a kind of single wire transmission technology of accurate control LED drive chip output current, the data terminal of N LEDs driving chips is cascaded by single line, chips at different levels receive first packet of input datas, after transmit the other parts of input data, the like.Therefore the number of signals that the present invention is sent is successively decreased step by step after chip, is reduced the data volume of transmission, is reduced the difficulty of data transfer.And the size of current of one single chip can be accurately controlled by signal, strengthen the control ability of single chip.
Description
Technical field
Single-wire data transmission control and transmission technology the present invention be directed to outdoor, the indoor LED drive integrated circults of application,
Specifically refer to a kind of single wire transmission technology of accurate control LED drive chip output current.
Background technology
At present, in the Single-wire data transmission of outdoor, the indoor LED drive chip of application, the method typically used is at side
The method for managing the transmission of data side, so causes the problem of volume of transmitted data is big, the requirement to transfer wire is very high.It is meanwhile right
The processing method of electric current is usually a regulation current order frame to control all chips, the so energy in control one single chip
Power is limited, if run into some lamp point handles the lamp point due to that when other factors cause electric current too small or be excessive, can only go.In reality
In the application of border, because the technique of IC chip processes the factors such as the change of inconsistency and application environment, it can cause passing
The pulse width of effective characterize data information narrows or broadened during transmission of data, so that when cascading more, pulse width
It can disappear or be not enough to characterize entrained information, final result is that data transfer is limited by cascade number and transmission range,
Prevent data excessive from cascading.In environmental change, chip internal clock frequency is also possible to find to change and make decoding
Mistake.It is an advantage of the invention that solving above mentioned problem with relatively simple method, meet and reduce data volume, control electric current essence
Really, the requirement of processing data and strong antijamming capability.
The content of the invention
It is an object of the invention to provide a kind of single wire transmission technology of accurate control LED drive chip output current, sheet
Invention can accurately control the electric current of one single chip, and can gradually reduce the quantity of transmission signal.
Technical solution of the present invention is as follows:
A kind of single wire transmission technology of accurate control LED drive chip output current, in transmitting procedure, single led driving core
Sheet data input/output signal line respectively has one, N number of LED drive chip cascade.After upper electricity, the bus of all chips, which is in, closes
State, chip can not transmission signal, be merely able to receive data.Exemplified by transmitting RGB data, when input data reaches first
During chip, chip receives data and decoded, and generates RGB data.After chip has received a packet, chip bus
It is opened.Follow-up data can be transmitted by the chip, and the chip and without decoding, and follow-up chip only receives 2-N
Chips data.When input data reaches the second chips, chip receives the second chips data, and is converted into RGB data,
Simultaneous transmission 3-N chips data.The like, N chips receive N chips data, and are converted into RGB data.
After the completion of all data are all transmitted, all chips produce a synchronizing signal, and the RGB data of all chips is converted into PWM
Waveform carries out output driving each LED.
Above-mentioned RGB data transmission means can equally transmit regulation current order, therefore can individually control single led driving
The output current of chip.
The LED drive chip can handle the input data slightly disturbed, such as the pulsewidth damage during transmission fruit
Mistake, clock jitter etc..
Signal is transferred to next stage chip after the latch of LED drive chip, can be reached by the latch of internal clocking
To the effect of signal reconstruction, the pulsewidth loss in cascade process is advantageously reduced, increases the cascade ability of chip.
The data-signal of transmission uses Manchester's code, it is necessary to meet frequency within 100Hz ~ 1.5MHz, and it is same
Change in duty cycle is no more than 25% when edge is effective.
Data Transport Protocol using 40bit (12bit) data as one group of data command unit structure, wherein comprising start bit,
Differentiate position, RGB data (current data), stop position.
The LED drive chip is except because of power supply stability and in addition to external capacitor, without other outer meeting resistance electric capacity.
The LED drive chip encapsulates for SOP8.
After the present invention, data can be reduced in the Single-wire data transmission of outdoor, the indoor LED drive chip of application
Transmission quantity, mitigate the load of wire, additionally it is possible to the output current of accurate control single chip, strengthen the fault-tolerant of chip and anti-dry
Ability is disturbed, makes single-wire cascade more convenient and stably.
Accompanying drawing is as follows with embodiment：
Brief description of the drawings
Fig. 1 LED drive chip schematic internal views.
Fig. 2 is for the cascade schematic diagram of the present invention.
Fig. 3 is Manchester's code schematic diagram.
Fig. 4 is Manchester's code schematic diagram.
Fig. 5 is chip data handling principle schematic diagram of the present invention.
Fig. 6 is chip internal operation principle state machine.
Embodiment
The present invention is used for the single wire transmission technology for accurately controlling LED drive chip output current, and its operation principle is：Passing
During defeated, single led driving chip data input output signal line respectively has one, N number of LED drive chip cascade.After upper electricity,
The bus of all chips is closed, chip can not transmission signal, be merely able to receive data.Using transmit RGB data as
Example, when input data reaches the first chips, chip receives data and decoded, and generates RGB data.When chip receives
After a complete packet, chip bus is opened.Follow-up data can be transmitted by the chip, and the chip and without
Decoding, follow-up chip only receive 2-N chips data.When input data reaches the second chips, chip receives second core
Sheet data, and RGB data is converted into, simultaneous transmission 3-N chips data.The like, N chips receive the N core
Sheet data, and it is converted into RGB data.After the completion of all data are all transmitted, all chips produce a synchronizing signal, own
The RGB data of chip is converted into PWM waveform and carries out output driving each LED.Inside LED drive chip as shown in figure 1, including
Decoding and transport module, parsing module, output module, clock module, energy supply control module.Wherein, energy supply control module is to core
Piece internal module is powered；Clock module produces chip internal clock, supplies modules；Decoding and transport module are to input signal
Decoded, stored and transmitted；Parsing module produces color and current data according to decoded result；Output module is according to parsing number
According to generation output waveform.The cascade of LED drive chip is as shown in Figure 2.
Manchester's code schematic diagram as shown in Figure 3 and Figure 4, in figure by taking Manchester's code " 1101 " and " 0010 " as an example
Illustrate, wherein containing trailing edge effective " 1 ", rising edge, effectively " 0 ", " 1 " change to " 0 " and " 0 " and changed to " 1 ".
Specifically data packet communication agreement frame structure is：
Data frame：2’b11+1’b1+12bitsR+12bitsG+12bitsB+1’b1
Adjust current order frame：2’b11+1’b0+8bitsDATA+1’b1
Communication protocol frame explanation：As described above, data frame includes the b11 of start bit 2 ', the b1 of position 1 ', 12 red datas are differentiated
12bitsR, 12 green datas 12bitsG, 12 blue data 12bitsB, the b1 of stop position 1 '；Regulation current order frame includes
The b11 of start bit 2 ', differentiate the b0 of position 1 ', 8 current data 8bitsDATA, the b1 of stop position 1 '.In transmission process, communication protocol frame
Order be start bit, differentiate position, data, stop position.The packet that all chips receive all is according to above-mentioned form and order
Arranged.
Transmission principle：After upper electricity, chip module register is resetted, and the bus of all chips is closed, chip now
The data sended over can only be received, and only receive and handle the data consistent with above-mentioned communication protocol frame structure, if differentiating position
For 1, then handled according to the structure of data frame, if differentiating, position is 0, at the structure according to regulation current order frame
Reason, after receiving, data that chip-stored receives, while bus is opened, and next core is transmitted data to by sdo
Piece.Next chips repeat said process.The function of bus is whether control chip can send data, when bus-off,
Chip only receives and processing data, does not send data；When bus is opened, chip is only latched with sending data, not processing data.
Therefore the data of chip transmission are reduced step by step.After all data are sent, the chip internal of all cascades can produce one
PWM synchronizing signals, the PWM or current data of storage are exported by output module, output signal out_r, out_
g、out_b.This completes the transmission of a frame data and display.Chip internal structure is as shown in figure 1, cascade schematic diagram such as figure
Shown in 2.
Decoding and transport module operation principle：This module provides internal clocking, internal clock frequencies scope by clock module
For 30-50MHz, the data frequency of reception is 100KHz-1.5MHz.With the cycle first_ of sdi first data received
Cycle_flg, using the trailing edge of internal clocking as triggering, calculates high level and low electricity in first data cycle as reference
Flat quantity is respectively Tcycle_in_first_cycle_high and Tcycle_in_first_cycle_low.At first
After cycle, it is Tcycle_tmp to calculate low and high level number, works as formula
Tcycle_tmp>=Tcycle_in_first_cycle_low+(Tcycle_in_first_cycle_low+Tcycle_
In_first_cycle_high)/4 (formula 1)
Or
Tcycle_tmp>=Tcycle_in_first_cycle_high+(Tcycle_in_first_cycle_low+Tcycle_
In_first_cycle_high)/4 (formula 2)
During establishment, the conversion between " 0 " and " 1 ", i.e. active_posedge conversion are represented.Active_posedge approximation generations
The table value of Manchester's code, when Manchester's code is " 1 ", active_posedge is low level；Manchester's code
For " 0 " when, active_posedge is high level.As long as active_posedge value, mclk and mdata is accurately determined
Just can accurately it decode.Obtained mclk mdata is output to parsing module.Mclk is input data sdi clock signal,
Mdata is input data sdi data-signal.Meanwhile bus signals open_bus also determines whether decoding process is carried out.This mould
Another effect of block is exactly, and when bus is opened, latches sdi, and pass through sdo output datas to next chips.And work as institute
After the completion of having data transfer, the module produces PWM synchronizing signal pwm_sync, and it is defeated to be output to output module control output waveform
Go out.This process is as seen from Figure 5.
Parsing module operation principle：The mclk and mdata that the module receives decoding and transport module obtains, and parse electricity
Flow data ga_out and color data rdata, gdata, bdata.The state machine of the module is as shown in fig. 6, state machine name is
rec_state.State machine initial state is 00, under mclk edging triggers, if continuously receiving the mdata of two high level,
State machine enters 01 state, and otherwise state machine is maintained at 00 state.Differentiate state 01, if the mdata received is high level,
State machine enters 11 data modes, needs to receive the color data of 36 below, be respectively 12bitsR, 12bitsG,
12bitsB, receive rear 12bitsR, 12bitsG, 12bitsB and be stored in respective register rdata, gdata, bdata respectively,
Receive a high level mdata again simultaneously and return to initial state 00.Differentiate state 01, if the mdata received is low level,
State machine enters 10 regulation current order states, and it is current data 8bitsDATA to need to receive 8 below, after receiving
8bitsDATA is stored in ga_out registers, while receives a high level mdata again and return to initial state 00.When state machine from
When 10 and 11 states return to 00 state, open_bus is changed into high level from low level, and bus is changed into opening from closing.And when all
After data transfer, open_bus becomes low level by high level, is always to be changed into closing from opening.This process can also lead to
Fig. 5 is crossed to find out.
Output module operation principle：The module receives pwm_sync signals, color data rdata, gdata, bdata, electricity
Flow data ga_out, and internally in the presence of clock, PWM waveform is produced according to color data, passes through PWM waveform and ga_
Out, produce signal out_r, out_g, the out_b that can drive LED.
The effect of energy supply control module is to receive 4-12V external power source, gives internal module stable power-supplying, enables the chip to
The normal work in the range of larger supply voltage, the fluctuation range of supply internal module voltage is 3-3.6V.
The main function of clock module is to produce stable internal clock signal, is supplied to internal module, can be just
Often parse the data received, it is desirable to which clock caused by the module can match with the fault-tolerant ability of processing unit, by other
Factor such as temperature, power supply influence is smaller, and the present invention disclosure satisfy that demand.
Above example is used for illustrative purposes only, rather than limitation of the present invention, person skilled in the relevant technique,
Without departing from the spirit and scope of the present invention, various conversion and change can also be made.Therefore, all equivalent skills
Art scheme should also belong to scope of the invention, should be limited by each claim.
Claims (9)
- A kind of 1. single wire transmission technology of accurate control LED drive chip output current, it is characterised in that：Plurality of LEDs drives core Piece is cascaded by single line, and the function that LED drive chip must include is decoding, converts data to RGB and current data, production Raw PWM waveform, in communication process, chip absorbs first packet of input data, and is carried out by using internal clocking Packet, is converted into RGB or current data by decoding, other input numbers of transmission in addition to first packet after converting According to.
- 2. it is used for a kind of single line transmission method of accurate control LED drive chip output current, its feature as claimed in claim 1 It is：After input data is sent, all chips produce synchronizing signals and according to the data output electric currents being respectively received and PWM waveform.
- 3. it is used for a kind of single line transmission method of accurate control LED drive chip output current, its feature as claimed in claim 1 It is：Signal is transferred to next stage chip after the latch of LED drive chip, can reach letter by the latch of internal clocking Number effect rebuild, advantageously reduces the pulsewidth loss in cascade process, increases the cascade ability of chip.
- 4. it is used for a kind of single line transmission method of accurate control LED drive chip output current, its feature as claimed in claim 1 It is：The three-polar output of the LED drive chip connects peripheral red, green and blue LED circuit for lamp respectively, is reached by the control of PWM waveform To the effect of display.
- 5. it is used for a kind of single line transmission method of accurate control LED drive chip output current, its feature as claimed in claim 1 It is：The LED drive chip can handle the input data slightly disturbed, as transmit fruit during pulsewidth loss, Clock jitter etc..
- 6. it is used for a kind of single line transmission method of accurate control LED drive chip output current, its feature as claimed in claim 1 It is：The data-signal of transmission uses Manchester's code, it is necessary to meet frequency within 100Hz ~ 1.5MHz, and same edge Change in duty cycle is no more than 25% when effectively.
- 7. it is used for a kind of single line transmission method of accurate control LED drive chip output current, its feature as claimed in claim 1 It is：The LED drive chip internal clocking is maintained within the scope of 30 ~ 50MHz, once chip manufacturing is completed, then frequency base This holding is stable.
- 8. it is used for a kind of single line transmission method of accurate control LED drive chip output current, its feature as claimed in claim 1 It is：The LED drive chip is except because of power supply stability and in addition to external capacitor, without other outer meeting resistance electric capacity.
- 9. it is used for a kind of single line transmission method of accurate control LED drive chip output current, its feature as claimed in claim 1 It is：The LED drive chip encapsulates for SOP8.
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109410828A (en) * | 2018-11-29 | 2019-03-01 | 宗仁科技(平潭)有限公司 | LED point light source driving method, system and controller |
| CN109887462A (en) * | 2019-04-08 | 2019-06-14 | 大连集思特科技有限公司 | A kind of one wire system LED display control system |
| CN110120198A (en) * | 2019-05-10 | 2019-08-13 | 深圳市惠博升科技有限公司 | A kind of LED lamp bead, LED display system and LED display |
| CN110176208A (en) * | 2019-03-21 | 2019-08-27 | 深圳市天微电子股份有限公司 | The control method that signal transmits between illuminating module and luminescence chip |
| CN110471882A (en) * | 2019-08-22 | 2019-11-19 | 矽恩微电子(厦门)有限公司 | A kind of monobus telecommunication circuit and method |
| CN111526634A (en) * | 2020-05-11 | 2020-08-11 | 中科芯集成电路有限公司 | Digital control module of flexible transparent screen LED driving chip |
| CN112654109A (en) * | 2020-12-30 | 2021-04-13 | 深圳市天微电子股份有限公司 | Light-emitting module, display screen and control method for signal transmission among light-emitting chips |
| CN113966025A (en) * | 2021-10-26 | 2022-01-21 | 深圳市紫光照明技术股份有限公司 | Dimming method, dimming controller and dimming control system |
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| CN105246186A (en) * | 2014-07-08 | 2016-01-13 | 苏州卓能微电子技术有限公司 | LED drive chip output current accurate control technology |
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2016
- 2016-06-24 CN CN201610467416.3A patent/CN107548185A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105246186A (en) * | 2014-07-08 | 2016-01-13 | 苏州卓能微电子技术有限公司 | LED drive chip output current accurate control technology |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109410828A (en) * | 2018-11-29 | 2019-03-01 | 宗仁科技(平潭)有限公司 | LED point light source driving method, system and controller |
| CN110176208A (en) * | 2019-03-21 | 2019-08-27 | 深圳市天微电子股份有限公司 | The control method that signal transmits between illuminating module and luminescence chip |
| CN109887462A (en) * | 2019-04-08 | 2019-06-14 | 大连集思特科技有限公司 | A kind of one wire system LED display control system |
| CN110120198A (en) * | 2019-05-10 | 2019-08-13 | 深圳市惠博升科技有限公司 | A kind of LED lamp bead, LED display system and LED display |
| CN110471882A (en) * | 2019-08-22 | 2019-11-19 | 矽恩微电子(厦门)有限公司 | A kind of monobus telecommunication circuit and method |
| CN111526634A (en) * | 2020-05-11 | 2020-08-11 | 中科芯集成电路有限公司 | Digital control module of flexible transparent screen LED driving chip |
| CN112654109A (en) * | 2020-12-30 | 2021-04-13 | 深圳市天微电子股份有限公司 | Light-emitting module, display screen and control method for signal transmission among light-emitting chips |
| CN112654109B (en) * | 2020-12-30 | 2023-02-28 | 深圳市天微电子股份有限公司 | Light-emitting module, display screen and control method for signal transmission among light-emitting chips |
| CN113966025A (en) * | 2021-10-26 | 2022-01-21 | 深圳市紫光照明技术股份有限公司 | Dimming method, dimming controller and dimming control system |
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