CN103813579A - Light emitting diode driving circuit and driving system of light emitting diode - Google Patents

Abstract

A light emitting diode driving circuit and a light emitting diode driving system are suitable for driving at least one light emitting diode, wherein the light emitting diode driving circuit comprises two shift register units and a data storage unit. The two shift register units can respectively store values of different bits in a plurality of brightness setting data, and the data storage unit can be used to temporarily store the value stored in one of the shift register units. Through the above circuit architecture, the light emitting diode driving circuit can use the values of multiple bits to drive the light emitting diode in the same driving cycle, thereby increasing the driving efficiency of the light emitting diode driving circuit.

Description

Light-emitting diode drive circuit and light-emitting diode drive system

technical field

The present invention relates to a light-emitting diode driving circuit, and in particular to a light-emitting diode driving circuit and a driving system in which a single driving output terminal can drive a light-emitting diode according to the value of two bits.

Background technique

Light Emitting Diode (LED for short) is a solid-state light-emitting element composed of P-type and N-type semiconductor materials, which can generate self-radiating light in the ultraviolet, visible and infrared regions. Due to the many advantages of LEDs such as power saving, long lifespan, and high brightness, under the trend of environmental protection, energy saving and carbon saving, LEDs are more and more widely used, such as traffic signals, street lights, flashlights, backlight modules for liquid crystal displays, or LED Various lighting devices such as light bulbs.

The LED display industry is currently aiming at high color scale resolution, high screen refresh rate, high LED utilization rate, high scan count, multiple driver chips connected in series, and cost reduction. The price of the basic driver chip is relatively cheap, but in the application of the scanning screen to achieve high color resolution, high screen refresh rate, and high number of scans will cause the defects of reduced LED utilization rate and fewer chips in series. Although the more expensive driver chip with built-in pulse width modulation (PWM) function can easily achieve the goal of high color resolution and high LED utilization under the application of scanning screen, but if you want to pursue high image quality The refresh rate must reduce the number of chips connected in series and the number of scans. And the cost of the driver chip with built-in pulse width modulation (PWM) function will increase a lot.

In order to improve the LED utilization rate (effective rate) and refresh rate (refresh rate), the LED driving method proposed by some traditional technologies will use multiple bits of data to drive in the same driving cycle, but the general circuit The architecture cannot provide multiple bits for multiple brightness settings at the same time.

Contents of the invention

The present invention provides a light-emitting diode driving circuit and its driving system. The light-emitting diode driving circuit has two shift temporary storage units and a data storage unit, which can simultaneously store two-bit data and perform data update on one output terminal. This makes it suitable for LED driving methods that require multiple bits to drive.

An embodiment of the present invention proposes a light emitting diode driving circuit, suitable for driving at least one light emitting diode, including a first shift temporary storage unit, a second shift temporary storage unit, a path selection unit, a data storage unit, a The output selection unit and a driving unit. The first shift register unit is used to receive a first data in a brightness setting data; the second shift register unit is used to receive a second data in a brightness setting data; the path selection unit is coupled to The first shift register unit and the second shift register unit switch to the output of the first shift register unit or the output of the second shift register unit according to a path selection signal; the data storage unit Coupled to the first shift register unit, storing the first data in the first shift register according to a latch signal.

The output selection unit is coupled to the data storage unit and the second shift register unit, and selects to output the value stored in the data storage unit or the value stored in the second shift register unit according to an output selection signal. The driving unit is coupled to the output selection unit, and determines a light-emitting time of the light-emitting diodes according to the value stored in the data storage unit, the value stored in the second shift register unit and an enable signal.

In an embodiment of the present invention, the above-mentioned first shift register unit and the second shift register unit respectively obtain the first data and the second data from the brightness setting value according to the path selection signal.

In an embodiment of the present invention, the driving unit includes at least one logic gate and a driving output circuit, the two input terminals of the logic gate are respectively coupled to the enable signal and the output of the output selection unit, and the logic gate's The output end is coupled to the driving output circuit.

In an embodiment of the present invention, the LED driving circuit further includes a signal generation unit coupled to the output selection unit, the path selection unit and the data storage unit, the signal generation unit is based on a switching signal and the enable The combination of signals outputs the output selection signal, the path selection signal and the latch signal.

In another embodiment of the present invention, the LED driving circuit further includes a signal generation unit coupled to the output selection unit, the path selection unit and the data storage unit, the signal generation unit is based on a switching signal and a data A combination of clock signals outputs the output selection signal, the path selection signal and the latch signal.

The present invention further proposes a driving system for LEDs, which includes a control unit and the above-mentioned LED driving circuit. The control unit is used for outputting an enabling signal and a brightness setting data to the LED driving circuit.

To sum up, the light-emitting diode drive circuit and its drive system of the present invention have two shift temporary storage units and a data storage unit, and can store two bits of data at the same time for a drive output to provide the drive unit in a single drive. Periodically drive the LEDs. The circuit structure of the present invention can be applied to the driving method using multiple bits, and the circuit structure is simple, low in cost and can achieve the technical effect of obtaining multiple bits simultaneously to improve the driving performance without increasing the data transmission bandwidth.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, preferred embodiments will be described in detail below together with the accompanying drawings.

Description of drawings

FIG. 1 shows a schematic diagram of a driving system of a light emitting diode according to an embodiment of the present invention.

FIG. 2 shows a schematic diagram of a light emitting diode driving circuit according to an embodiment of the present invention.

FIG. 3A shows a circuit diagram of the LED driving circuit 120 according to the embodiment of the present invention.

FIG. 3B is a schematic diagram of a signal generating unit according to another embodiment of the present invention.

FIG. 4 is a schematic diagram of signal waveforms according to an embodiment of the present invention.

[Description of main component symbols]

Drive system: 100

LEDs: 101

Control unit: 110

LED drive circuit: 120

The first shift temporary storage unit: 210

The second shift temporary storage unit: 220

Path selection units: 230

Data Storage Units: 240

Output selection units: 250

Drive unit: 260

Signal generation unit: 310

AND gate: 311, 321

Shift register: 312, 322

Inversion gate: 323

AND gate: 351~35P

Drive output circuit: 361~36P

Waveform: 411~418

Output terminal: OUT1~OUTP

Output selection signal: SOUT

First clock signal: CLK1

Second clock signal: CLK2

Data input signal: DIN

Data output signal: DO

Data clock signal: DCK

Latch signal: LAT

Enable signal: EN

Inverted enable signal: ENB

Path selection signal: SEL

Switching signal: SW

Detailed ways

Hereinafter, the present invention will be described in detail by illustrating embodiments of the invention in the drawings, and the same reference numerals in the drawings may be used to denote similar elements.

Please refer to FIG. 1 , which shows a schematic diagram of a driving system of a light emitting diode according to an embodiment of the present invention. The driving system 100 includes a control unit 110 and an LED driving circuit 120 . The control unit 110 is coupled to the LED driving circuit 120 and outputs an enable signal EN and a data input signal DIN to the LED driving circuit 120 . The LED driving circuit 120 drives the LED 101 according to the enable signal EN and the data input signal DIN to generate gray scale changes. The control unit 110 is, for example, a controller of the LED display screen, which can be used to process and output display data, and can also provide switching signals, data latch signals or data clock signals to the LED driving circuit 120 .

According to different chip specifications and design requirements, the control unit 110 may have different functions, and this implementation is not limited. The LED driving circuit 120 is, for example, a LED driver chip, which is mainly used to provide a driving current to drive the LED 101 . The LED driving circuit 120 can adjust the gray scale (brightness) generated by the LED 101 by using the magnitude of the current or the timing of the current output. The control unit 110 and the LED driving circuit 120 may be connected via a printed circuit board or a signal line, and this embodiment does not limit the connection relationship between the control unit 110 and the LED driving circuit 120 .

Please refer to FIG. 2 , which shows a schematic diagram of an LED driving circuit according to an embodiment of the present invention. The LED driving circuit 120 includes a first shift register unit 210 , a second shift register unit 220 , a path selection unit 230 , a data storage unit 240 , an output selection unit 250 and a drive unit 260 . The input ends of the first shift register unit 210 and the second shift register unit 220 are coupled to the data input end of the LED driving circuit 120 for receiving the data input signal DIN. The data input signal DIN includes brightness setting data, which is used to represent the driving brightness of individual LEDs 101. The encoding method of the data input signal DIN is, for example, general serial data, DMX512 protocol, and Manchester encoding (MANCHESTER Encoding). However, in this embodiment The encoding method is not limited to this.

Output terminals of the first shift register unit 210 and the second shift register unit 220 are coupled to the path selection unit 230 for transmitting data. The output terminal of the path selection unit 230 is used to output the data output signal DO. The data storage unit 240 is coupled to the first shift register unit 210 for storing data in the first shift register unit 210 . The output selection unit 250 is coupled to the data storage unit 240 and the second shift register unit 220 for selecting and outputting data in the data storage unit 240 or the second shift register unit 220 .

The first shift temporary storage unit 210 and the second shift temporary storage unit 220 are mainly used to temporarily store the brightness setting data in the data input signal DIN from the control unit 110, which can be set according to the bit order of the data input signal DIN Data related to the two brightness setting values are stored in two temporary storage areas respectively. The brightness setting data in the data input signal DIN is, for example, n-bit grayscale data (n is a positive integer). The gray scale data corresponds to the brightness setting value of the light-emitting diode at the individual output terminal, and different output terminals may have different brightness setting values. The LED driving circuit 120 determines the brightness of the driven LEDs according to the brightness setting data.

The first shift register unit 210 and the second shift register unit 220 respectively receive the first data and the second data in the brightness setting data according to the path selection signal SEL, such as values of different bits of the gray scale data. Taking 8-bit brightness setting data as an example, the first shift and temporary storage unit 210 can perform data shift and temporary storage when the path selection signal SEL is at a high level to obtain multiple pieces of brightness setting data corresponding to different output terminals. The value of the second bit, and the second shift temporary storage unit 220 can perform data shift temporary storage when the path selection signal SEL is low level to obtain the third one of the multiple brightness setting data corresponding to different output terminals bit value. The data of the data input signal DIN is transmitted to the first shift register unit 210 and the second shift register unit 220 at different times, whereby the first shift register unit 210 and the second shift register unit 220 can be Get a different bit value or data. The first shift register unit 210 and the second shift register unit 220 can be composed of: R-S flip-flop, D-type flip-flop, T-type flip-flop, JK flip-flop, D-type latch flip-flops or latches, but this embodiment is not limited.

The first shift register unit 210 and the second shift register unit 220 can have a plurality of data storage elements, and can simultaneously store bit values of multiple pieces of brightness setting data to correspond to multiple drive output terminals. For example, the number of bits that can be stored in the first shift register unit 210 and the second shift register unit 220 can be the same as the number of output terminals OUT1~OUTP of the drive unit 260, but this embodiment does not limit .

The path selection unit 230 switches whether the transmitted data is from the first shift register unit 210 or the second shift register unit 220 according to the path select signal SEL. For example, when the first shift temporary storage unit 210 performs data acquisition, the path selection unit 230 will switch to the first shift temporary storage unit 210, so that the data in the first shift temporary storage unit 210 can be transferred to the next A first shift temporary storage unit in a light emitting diode drive circuit (driver chip). When the second shift temporary storage unit 220 performs data acquisition, the path selection unit 230 will switch to the second shift temporary storage unit 220, so that the data in the first shift temporary storage unit 220 can be transferred to the next LED driver The second shift temporary storage unit in the circuit (driver chip). The path selection unit 230 is, for example, a multiplexer, but this embodiment is not limited thereto.

The data storage unit 240 stores the data in the first shift temporary storage unit 210 according to the data latch signal LAT, and the first shift temporary storage unit 210 can perform data update after the data is acquired by the data storage unit 240 . In other words, the data latch signal LAT and the path selection signal SEL have a timing relationship, and the data storage unit 240 acquires and temporarily stores the first data in accordance with the data update timing of the first shift register unit 210 . Taking the aforementioned 8-bit brightness setting data as an example, the data storage unit 240 may temporarily store the value of the second bit stored in the first shift register unit 210 . The data storage unit 240 is, for example, composed of multiple R-S flip-flops, D-type flip-flops, T-type flip-flops, JK flip-flops, D-type latches, and other flip-flops or latches in parallel. , but this embodiment is not limited.

The output selection unit 250 selects to output the value stored in the data storage unit 240 or the value stored in the second shift register unit 220 to the driving unit 260 according to the output selection signal SOUT. For example, the output selection unit 250 can output the value of the 2nd bit in the data storage unit 240 and the value of the 3rd bit stored in the second shift register unit 220 to the driver in one LED driving cycle. Unit 260.

The driving unit 260 has a plurality of output terminals OUT1 - OUTP (P is a positive integer) for coupling to the LED 101 . The driving unit 250 can adjust the current of the output terminals OUT1 ˜ OUTP to drive the plurality of LEDs 101 . Generally speaking, the driving unit 250 has a plurality of constant current circuits, which can respectively control the currents flowing into the output terminals OUT1 ˜ OUTP to determine the light-emitting time and brightness of the light-emitting diodes 101 . The direction of the current can be determined according to the design requirements and the driving direction of the light emitting diode 101 . The present embodiment does not limit the current output direction of the driving unit 250 and the circuit design structure of the constant current circuit.

The driving unit 260 determines the light-emitting time of the LEDs according to the enable signal EN and the output of the output selection unit 250 . In other words, the driving unit 260 determines the light-emitting time of the LEDs connected to the driving terminals OUT1 ˜ OUTP according to the value stored in the data storage unit 240 , the value stored in the second shift register unit 220 and the enable signal EN. For example, the driving unit 260 can divide a driving cycle into two sub-cycles, and then determine the effective light-emitting time in the first sub-cycle according to the value stored in the data storage unit 240, according to the second shift register unit 220 The value stored in determines the effective light-emitting time in the second sub-cycle. Through the architecture of the LED driving circuit 120 , the driving unit 260 can determine the lighting time of the LED according to the value of two bits in the brightness setting data in a single sub-period.

Since the LED driving circuit 120 has two shift register units 210 , 220 and a data storage unit 240 , the LED driving circuit 120 can update and drive data at the same time. For example, the first shift register unit 210 and the second shift register unit 220 can respectively store the first bit (first data) and the second bit of a plurality of brightness setting values according to the path selection signal SEL. One bit (second data). Then, the data storage unit 240 will obtain the value of the first bit from the first shift temporary storage unit 210. After the data storage unit 240 completes the storage of the first bit, the first shift temporary storage unit 210 can Perform data update. At this time, the output selection unit 250 can output the value in the second shift register unit 220 or the value in the data storage unit 240 to the driving unit 260 to drive the LED.

After the first shift register unit 210 finishes updating the data, the second shift register unit 220 can then update the data, and at this time, the output selection unit 250 can output the data in the data storage unit 240 to drive the LED. In other words, the second shift register unit 220 can perform data update when the output selection unit 250 switches to the data storage unit 240 , while the first shift register unit 210 can obtain the first shift register unit 240 at the data storage unit 240 The data in cell 210 is then updated with data. That is to say, when the output selection unit 250 switches to the second shift temporary storage unit 220 again, the second shift temporary storage unit 220 has completed the action of updating the data, and the driving unit 260 does not need to wait for the data update time. Get the next brightness setting data or the next required bit value to drive the LED.

It is worth noting that the path selection signal SEL, the latch signal LAT, the enable signal EN and the output selection signal SOUT can be provided by an external circuit (such as the control unit 110) or by an internal circuit of the LED driving circuit 120. In this implementation Examples are not limited.

Please refer to FIG. 3A , which is a circuit diagram of the LED driving circuit 120 according to an embodiment of the present invention. The driving unit 260 may be composed of a plurality of logic gates and driving output circuits, such as a plurality of AND gates (AND gates) 351 - 35P and driving output circuits 361 - 36P. The input terminals of the AND gates 351~35P respectively receive the enable signal EN and the output of the output selection unit 250, and the output terminals of the AND gates 351~35P are coupled to the driving output circuits 361~36P, and the output selection unit 250 The output of the drive output circuits 361-36P determines whether to drive the LED 101 or not. It can be seen from FIG. 3A that when the enable signal EN is at a logic high potential and the output of the output selection unit 250 is at a logic high potential (logic 1), the outputs of the AND gates 351~35P can be enabled, so that the drive output circuits 361~36P output current. The driving output circuits 361 - 36P are, for example, constant current output circuits, which can output a constant current to drive the LED 101 .

The LED drive circuit 120 further includes a signal generation unit 310 coupled to the output selection unit 250, the path selection unit 230 and the data storage unit 240, the signal generation unit 310 outputs the above-mentioned output selection signal according to the combination of the switching signal SW and the enable signal EN SOUT, path selection signal SEL and latch signal LAT.

Please refer to FIG. 3B , which is a schematic diagram of a signal generating unit according to another embodiment of the present invention. In another embodiment of the present invention, the signal generation unit 310 is coupled to the output selection unit 250, the path selection unit 230, and the data storage unit 240, and can output the above-mentioned output selection signals SOUT, Path selection signal SEL and latch signal LAT.

The output selection signal SOUT, the path selection signal SEL and the latch signal LAT are all related to the timing of data transmission, so as long as the relevant signals that can reflect the timing of the data input signal DIN can be used to generate the output selection signal SOUT, the path selection signal SEL and the latch The lock signal LAT, the present embodiment does not limit the generation method. It should be noted that all or part of the switching signal SW, enable signal EN, data input signal DIN, and data clock signal DCK in FIG. Limit how the signal is generated.

The first shift register unit 210 includes a logic gate (AND gate 311 ) and a shift register 312 , and the two input terminals of the AND gate 311 respectively receive the data clock signal DCK and the path selection signal SEL from the control unit 110 , The output end outputs the first clock signal CLK1 to the shift register 312 . The input end of the shift register 312 is coupled to the data input signal DIN, and the clock input end thereof is coupled to the output of the AND gate 311 .

The second shift register unit 220 includes logic gates (AND gate 321 and inversion gate 323 ) and a shift register 322 , and the two input terminals of the AND gate 321 respectively receive the data clock signal DCK and The output of the inverting gate 323 and the input of the inverting gate 323 are coupled to the path selection signal SEL. The output end of the AND gate 321 then outputs the second clock signal CLK2 to the shift register 322 . The input end of the shift register 322 is coupled to the data input signal DIN, and the clock input end thereof is coupled to the output of the AND gate 321 .

It can be known from the above circuit structure that when the path selection signal SEL is logic high, the first shift register unit 210 will update data, while the second shift register unit 220 will not update data; when the path selection signal SEL When SEL is logic low, the second shift register unit 220 will perform data update, while the first shift register unit 210 will not perform data update.

Using the path selection signal SEL, the first shift register unit 210 and the second shift register unit 220 can obtain brightness setting data in the data input signal DIN at different timings. Moreover, the first shift register unit 210 and the second shift register unit 220 temporarily store the brightness setting data in the data input signal DIN according to the data clock signal DCK.

Next, please refer to FIG. 4 at the same time. FIG. 4 is a schematic diagram of signal waveforms according to an embodiment of the present invention. 4 shows the above-mentioned data input signal DIN, data clock signal DCK, switching signal SW, enable signal EN, inverted enable signal ENB, path selection signal SEL, second clock signal CLK2, first clock signal CLK1, latch The timing relationship between the lock signal LAT and the output selection signal SOUT.

When the waveform 411 of the path selection signal SEL is at a high level, the first shift temporary storage unit 210 acquires the values of multiple high-order bits MSB (for example, the fifth bit) in the multiple pieces of brightness setting data through the data input signal DIN, and then When the waveform 411 of the path selection signal SEL is switched to the low-level waveform 412, the second shift temporary storage unit 220 acquires a plurality of low-order bits LSB (for example, the first bit) in the multiple brightness setting data through the data input signal DIN yuan) value. Then, the latch signal LAT generates an enable pulse 413 , so that the data storage unit 240 acquires the values of a plurality of upper bits MSB in the first shift register unit 210 . Then, when the waveform 414 of the output selection signal SOUT is at a low level, the output selection unit 250 will output the values of the plurality of lower bit LSBs stored in the second shift register unit 220 .

The enable waveform 415 (high level) of the enable signal EN enables the driving unit 260 to drive the LED 101 according to the values of the plurality of lower bits LSB stored in the second shift register unit 220 . At this time, the path selection signal SEL is switched to a high-level waveform 416 to enable the first shift register unit 210 to update data. Then, the waveform 418 of the output selection signal SOUT will switch to a high level correspondingly, so that the output selection unit 240 outputs the value stored in the data storage unit 240 to the drive unit 260, and then the enable signal EN switches to a high level enabling waveform 417 , so that the driving unit 260 drives the light-emitting diode 101 according to the values of a plurality of upper bits MSB stored in the data storage unit 240 . By analogy, the LED driving circuit 120 can continuously update the data and drive the LEDs according to the new data.

It should be noted that the above-mentioned waveform is only one of the implementation modes for illustrating the circuit of this embodiment, and the enable level of each signal can be determined according to the design requirements. After the description of the above-mentioned embodiment, those of ordinary skill in the art should The remaining implementation manners can be easily deduced, and will not be repeated here.

In addition, it should be noted that the coupling relationship between the above elements includes direct or indirect electrical connection, as long as the required electrical signal transmission function can be achieved, the present invention is not limited. The technical means in the above-mentioned embodiments can be combined or used alone, and its elements can be added, removed, adjusted or replaced according to their functions and design requirements, and the present invention is not limited. After the description of the above-mentioned embodiments, those skilled in the art should be able to infer the implementation manner thereof, and details are not repeated here.

To sum up, the structure of the light emitting diode drive circuit proposed by the embodiment of the present invention can store different bit values in multiple brightness setting data at the same time, so that the drive circuit can use multiple bit values to Driving, thereby improving the utilization rate of the light emitting diode and the refresh rate of the picture.

Although the embodiments of the present invention have been disclosed above, the present invention is not limited to the above embodiments, and any person of ordinary skill in the art may make some modifications and changes without departing from the disclosed scope of the present invention. Therefore, the scope of protection of the present invention shall prevail as defined by the scope of the appended patent application.

Claims (12)

1. A light-emitting diode drive circuit, suitable for driving at least one light-emitting diode, characterized in that, the light-emitting diode drive circuit comprises: The first shift register unit is used to receive a first data in a brightness setting data; The second shift register unit is used to receive a second data in a brightness setting data; a path selection unit, coupled to the first shift register unit and the second shift register unit, and switches to the output of the first shift register unit or the second shift register unit according to a path selection signal The output of the shift register unit; a data storage unit, coupled to the first shift register unit, for storing the first data in the first shift register according to a latch signal; An output selection unit, coupled to the data storage unit and the second shift temporary storage unit, selects and outputs the value stored in the data storage unit or the second shift temporary storage unit according to an output selection signal the stored value; and A driving unit, coupled to the output selection unit, determines the light-emitting time of the light-emitting diode according to the value stored in the data storage unit, the value stored in the second shift register unit and an enable signal . 2. The light emitting diode drive circuit according to claim 1, wherein the first shift register unit and the second shift register unit are respectively set from the brightness according to the path selection signal. The first data and the second data are obtained from the data. 3. The LED driving circuit according to claim 1, wherein the path selection signal, the output selection signal and the latch signal are generated by an internal circuit. 4. The light emitting diode driving circuit according to claim 1, wherein the driving unit comprises at least one logic gate and a driving output circuit, two input terminals of the logic gate are respectively coupled to the enable The signal is connected to the output of the output selection unit, and the output terminal of the logic gate is coupled to the driving output circuit. 5. The light emitting diode driving circuit according to claim 1, wherein the light emitting diode driving circuit further comprises: a signal generation unit coupled to the output selection unit, the path selection unit and the data storage unit, the signal generation unit outputs the path selection signal according to a combination of a switch signal and the enable signal, The output select signal and the latch signal. 6. The light emitting diode driving circuit according to claim 1, wherein the light emitting diode driving circuit further comprises: a signal generation unit coupled to the output selection unit, the path selection unit and the data storage unit, the signal generation unit outputs the path selection signal and the path selection signal according to a combination of a switching signal and a data clock signal the output selection signal and the latch signal. 7. The light emitting diode drive circuit according to claim 1, wherein the second shift temporary storage unit is capable of updating data when the output selection unit selects to output the data storage unit, and the first The shift temporary storage unit can update data after the data storage unit acquires the data of the first shift temporary storage unit. 8. A drive system for light emitting diodes, characterized in that the drive system comprises: a control unit for outputting an enable signal and a brightness setting data; and A light emitting diode driving circuit, coupled to the control unit, the light emitting diode driving circuit includes: a first shift register unit, configured to receive a first piece of data in the brightness setting data; a second shift register unit, configured to receive a second data in the brightness setting data; a path selection unit, coupled to the first shift register unit and the second shift register unit, and switches to the output of the first shift register unit or the second shift register unit according to a path selection signal The output of the shift register unit; a data storage unit, coupled to the first shift register unit, for storing the first data in the first shift register according to a latch signal; An output selection unit, coupled to the data storage unit and the second shift temporary storage unit, selects and outputs the value stored in the data storage unit or the second shift temporary storage unit according to an output selection signal the stored value; and The driving unit is coupled to the output selection unit, and determines the light-emitting time of the light-emitting diode according to the value stored in the data storage unit, the value stored in the second shift register unit and an enabling signal. 9. The driving system of a light emitting diode according to claim 8, wherein the first shift temporary storage unit and the second shift temporary storage unit are respectively selected from the brightness setting according to the path selection signal. Obtain the first data and the second data from certain data. 10. The LED driving system according to claim 8, wherein the control unit can output a switching signal, and the LED driving circuit outputs according to the combination of the switching signal and the enable signal The path selection signal, the output selection signal and the latch signal. 11. The LED driving system according to claim 8, wherein the control unit is capable of outputting a switching signal and a data clock signal, and the LED driving circuit is based on the switching signal and the clock signal combination to output the path selection signal, the output selection signal and the latch signal. 12. The driving system of light emitting diode according to claim 8, characterized in that, the second shift temporary storage unit can update data when the output selection unit selects to output the data storage unit, and the second A shift temporary storage unit can update data after the data storage unit acquires the data of the first shift temporary storage unit.

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