TWI491304B - Led driver circuit and driver system - Google Patents

Description

LED driving circuit and drive system

The present invention relates to a light emitting diode driving circuit, and more particularly to a light emitting diode driving circuit and a driving system capable of driving a light emitting diode according to the value of two bits at a single driving output end.

Light Emitting Diode (LED) 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. LEDs have many advantages such as power saving, long life and high brightness. Recently, LEDs have become more and more widely used in environmental protection, energy saving and carbon saving. For example, traffic signs, street lamps, flashlights, LCD backlight modules or For example, various types of lighting devices such as LED bulbs.

The LED display industry is currently developing targets with high color resolution, high picture refresh rate, high LED utilization, high scan count, multi-drive chip serial number and cost reduction. It is cheaper to use the basic driver chip, but to achieve high color gradation resolution, high picture refresh rate, and high scan number in the application of the scanning screen, the LED utilization rate is reduced and the number of serially connected chips is reduced. The driver chip with more expensive built-in pulse width modulation (PWM) function can easily achieve the goal of high gradation resolution and high LED utilization rate under the application of scanning screen, but to pursue The high picture refresh rate must reduce the number of chips connected and the number of scans. And the cost of the driver chip using the built-in pulse width modulation (PWM) function will increase a lot.

The light-emitting diode driving method proposed by some conventional technologies is to increase the effective rate of the light-emitting diode and the refresh rate, and use multiple bits of data to drive in the same driving cycle. However, the general circuit architecture cannot provide multiple bits of multiple brightness settings at the same time.

The invention provides a light-emitting diode driving circuit and a driving system thereof, wherein the light-emitting diode driving circuit has two shifting temporary storage units and one data storage unit, and can simultaneously store two bits of data for one output end and perform The data is updated to make it suitable for a light-emitting diode driving method that requires multiple bits to drive.

The embodiment of the invention provides a light-emitting diode driving circuit, which is suitable for driving at least one light-emitting diode, and includes a first shift temporary storage unit, a second shift temporary storage unit, a path selection unit, and a data storage. A unit, an output selection unit and a drive unit. The first shift register unit is configured to receive a first data in a brightness setting data; the second shift register unit is configured to receive a second data in a brightness setting data; the path selecting unit is coupled to the first a shift register unit and the second shift register unit switch to an output of the first shift register unit or an output of the second shift register unit according to a path selection signal; the data storage unit is coupled The first shift register unit stores 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 temporary storage unit, and selects to output a value stored by the data storage unit or a value stored by the second shift temporary storage unit according to an output selection signal. The driving unit is coupled to the output selecting unit, and determines a lighting time of the LEDs according to the value stored by the data storage unit, the value stored by the second shift register unit, and the consistent energy signal.

In an embodiment of the invention, the first shift temporary storage unit and the second shift temporary storage unit respectively extract the first data and the second data from the brightness setting value according to the path selection signal.

In an embodiment of the invention, the driving unit includes at least one logic gate and A driving output circuit, the two input ends of the logic gate are respectively coupled to the output of the enable signal and the output selection unit, and the output end of the logic gate is coupled to the drive output circuit.

In an embodiment of the invention, the LED driving circuit further includes a signal generating unit coupled to the output selecting unit, the path selecting unit and the data storage unit, and the signal generating unit is configured according to a switching signal The combination of enable signals outputs the output select signal, the path select signal, and the latch signal.

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

The invention further provides a driving system for a light emitting diode, comprising a control unit and the above-mentioned light emitting diode driving circuit. The control unit is configured to output a uniform energy signal and a brightness setting data to the light emitting diode driving circuit.

In summary, the LED driving circuit of the present invention and its driving system have two shifting temporary storage units and one data storage unit, and one driving output terminal can simultaneously store two bits of data to provide a driving unit. The light-emitting diode is driven in a single driving cycle. The circuit architecture of the present invention can be applied to a multi-bit driving method, and has a simple circuit structure, low cost, and can achieve the technical effect of simultaneously obtaining a plurality of bits to improve driving efficiency without increasing the data transmission bandwidth.

The above described features and advantages of the present invention will be more apparent from the following description.

In the following, a detailed description of an embodiment of the invention will be provided The present invention is described, and the same reference numerals are used in the drawings.

Please refer to FIG. 1. FIG. 1 is 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 a light emitting diode driving circuit 120. The control unit 110 is coupled to the LED driving circuit 120 and outputs an enabling signal EN and a data input signal DIN to the LED driving circuit 120. The LED driving circuit 120 drives the LED 201 according to the enable signal EN and the data input signal DIN for generating gray scale changes. The control unit 110 is, for example, a controller of the LED display, and can be used to process and output display data, and can also provide a switching signal, a data latch signal or a data clock signal to the LED driving circuit 120.

The control unit 110 can have different functions according to different chip specifications and design requirements, and the implementation is not limited. The LED driving circuit 120 is, for example, a driving chip of a light emitting diode, and is mainly used to supply a driving current to drive the LED 201. The light emitting diode driving circuit 120 can adjust the gray scale (brightness) generated by the light emitting diode 101 by using the current magnitude or the current output timing. The control unit 110 and the LED driving circuit 120 can be connected via a printed circuit board or a signal line. This embodiment does not limit the connection relationship between the control unit 110 and the LED driving circuit 120.

Please refer to FIG. 2. FIG. 2 is a schematic diagram of a driving circuit of a light emitting diode 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 selecting unit 230, a data storage unit 240, an output selecting unit 250, and a driving unit 260. The first shift register unit 210 and the input end of 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. data The input signal DIN includes brightness setting data for indicating the driving brightness of the individual light-emitting diodes 101. The encoding method of the data input signal DIN is, for example, general serial data, DMX512 protocol, Manchester code (MANCHESTER Encoding), but this embodiment The encoding method is not limited to this.

The output of the first shift register unit 210 and the second shift register unit 220 is coupled to the path selecting unit 230 for transferring data. The output 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 temporary storage unit 210 for storing data in the first shift temporary storage unit 210. The output selection unit 250 is coupled to the data storage unit 240 and the second shift temporary storage unit 220 for selecting data in the output data storage unit 240 or the second shift temporary storage unit 220.

The first shift register unit 210 and the second shift register 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 based on the bit order of the data input signal DIN. The data related to the pen brightness setting value are stored in two temporary storage areas. The brightness setting data in the data input signal DIN is, for example, n-bit gray scale data (n is a positive integer). The gray scale data corresponds to the brightness setting value of the LEDs of the individual output terminals, and different output terminals may have different brightness setting values. The LED driving circuit 120 determines the brightness of the driven LED 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, for example, the values of different bits of the gray level data according to the path selection signal SEL. Taking the 8-bit brightness setting data as an example, the first shift register unit 210 can perform data shift temporary storage when the path selection signal SEL is at a high level to obtain multiple brightness setting data corresponding to different output ends. The value of the second bit, and the second shift register unit 220 may perform data shift temporary storage when the path selection signal SEL is at a low level. Corresponding to the value of the third bit in the multiple brightness setting data of different output terminals. The data of the data input signal DIN is transmitted to the first shift temporary storage unit 210 and the second shift temporary storage unit 220 at different times, whereby the first shift temporary storage unit 210 and the second shift temporary storage unit 220 can Capture different bit values or data. The first shift register unit 210 and the second shift register unit 220 can be: an RS flip-flop, a D-type flip-flop, a T-type flip-flop, a JK flip-flop, and a D-type latch. The device is constituted by a flip-flop or a latch, but the embodiment is not limited.

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

The path selection unit 230 switches the transferred data according to the path selection signal SEL from the first shift temporary storage unit 210 or the second shift temporary storage unit 220. For example, when the first shift register unit 210 performs data capture, the path selection unit 230 switches 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 first shift register unit in the next LED driving circuit (drive wafer). When the second shift register unit 220 performs data capture, the path selection unit 230 switches 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 light-emitting unit. A second shift register unit in the pole drive circuit (drive wafer). The path selection unit 230 is, for example, a multiplexer, but the embodiment is not limited.

The data storage unit 240 stores the data in the first shift temporary storage unit 210 according to the data latch signal LAT. The first shift temporary storage unit 210 can update the data after the data is retrieved by the data storage unit 240. In other words, the data latch signal LAT has a temporal relationship with the path selection signal SEL, and the data is stored. The unit 240 captures the first data in the data update timing of the first shift register unit 210 and temporarily stores it. Taking the brightness setting data of the above 8-bit as an example, the data storage unit 240 may temporarily store the value of the second bit stored in the first shift temporary storage unit 210. The data storage unit 240 is composed of, for example, a plurality of RS flip-flops, D-type flip-flops, T-type flip-flops, JK flip-flops, D-type latches, and the like, or a latch. However, the embodiment is not limited.

The output selection unit 250 selects the value stored in the output data storage unit 240 or the value stored in the second shift temporary storage unit 220 to the driving unit 260 according to the output selection signal SOUT. For example, the output selection unit 250 may output the value of the second bit in the data storage unit 240 and the third bit stored in the second shift temporary storage unit 220 in the driving cycle of one light emitting diode. The value is to the drive unit 260.

The driving unit 260 has a plurality of output terminals OUT1 OUTOUTP (P is a positive integer) for coupling the light emitting diode 101. The driving unit 250 can adjust the currents of the output terminals OUT1 to OUTP to drive the plurality of light emitting diodes 101. In general, the driving unit 250 has a plurality of constant current circuits that can respectively control the currents flowing into the output terminals OUT1 to OUTP to determine the lighting time and brightness of the LEDs 101. The direction of the current may be determined according to design requirements and the driving direction of the LED 201. This 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 lighting time of the light emitting diode according to the enable signal EN and the output of the output selecting unit 250. In other words, the driving unit 260 determines the illumination 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 temporary storage unit 220, and the enable signal EN. time. For example, the driving unit 260 can divide a driving cycle into two sub-periods, and then store according to the data storage unit 240. The stored value determines the effective illumination time in the first sub-period, and the effective illumination time in the second sub-period is determined according to the value stored in the second shift temporary storage unit 220. By the architecture of the LED driving circuit 120, the driving unit 260 can determine the lighting time of the LED according to the values of the two bits in the brightness setting data in a single sub-period.

Since the LED driving circuit 120 has two shift register units 210 and 220 and the data storage unit 240, the LED driving circuit 120 can simultaneously update and drive data. For example, the first shift register unit 210 and the second shift register unit 220 may respectively store the first bit (first data) and the second one of the plurality of brightness setting values according to the path selection signal SEL. Bit (second data). Then, the data storage unit 240 obtains 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 Update the data. At this time, the output selection unit 250 may output the value in the second shift temporary storage unit 220 or the value in the data storage unit 240 to the driving unit 260 to drive the light emitting diode.

After the first shift register unit 210 completes the data update, the second shift register unit 220 may perform the data update. At this time, the output selection unit 250 may output the data in the data storage unit 240 to drive the light emitting diode. body. In other words, the second shift temporary storage unit 220 can perform data update when the output selection unit 250 switches to the data storage unit 240, and the first shift temporary storage unit 210 can capture the first shift temporary at the data storage unit 240. The data in the storage unit 210 is followed by data update. That is, 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 update time of the data. Get the next brightness setting data or the next required bit value to drive the hair Light diode.

It should be noted that the path selection signal SEL, the latch signal LAT, the enable signal EN and the output selection signal SOUT may be provided by an external circuit (such as the control unit 110) or provided by an internal circuit of the LED driving circuit 120. This embodiment is not limited.

Referring to FIG. 3A, FIG. 3A is a circuit diagram of a light emitting diode 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, for example, a plurality of AND gates 351 to 35P and driving output circuits 361 to 36P. The input terminals of the gates 351~35P respectively receive the output of the enable signal EN and the output selection unit 250, and the output ends of the gates 351~35P are coupled to the drive output circuits 361~36P, according to the enable signal EN and the output selection unit 250. The output determines whether the drive output circuits 361 to 36P drive the light-emitting diode 101. As can be seen from FIG. 3A, when the enable signal EN is at a logic high level and the output of the output selection unit 250 is a logic high (logic 1), the outputs of the gates 351 to 35P can be enabled to cause the output of the drive output circuits 361 to 36P. Current. The drive output circuits 361 to 36P are, for example, constant current output circuits, and can output a constant current to drive the light-emitting diode 101.

The LED driving circuit 120 further includes a signal generating unit 310 coupled to the output selecting unit 250, the path selecting unit 230 and the data storage unit 240. The signal generating unit 310 outputs the output according to the combination of the switching signal SW and the enable signal EN. The signal SOUT, the path selection signal SEL, and the latch signal LAT are selected.

Please refer to FIG. 3B. FIG. 3B 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 generating unit 310 is coupled to the output selecting unit 250, the path selecting unit 230, and the data storage unit 240, and can be output according to the combination of the switching signal SW and the data clock signal DCK. The output selection signal SOUT, the path selection signal SEL, and the 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 transfer, so that any relevant signal 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, this embodiment does not limit the manner of generation. It should be noted that the signals of the switching signal SW, the enable signal EN, the data input signal DIN and the data clock signal DCK in FIG. 3A may be outputted to the LED driver circuit 120 in whole or in part by the control unit 110, but Embodiments do not limit the manner in which signals are generated.

The first shift register unit 210 includes a logic gate (and gate 311) and a shift register 312, and the two inputs of the gate 311 receive the data clock signal DCK and the path select signal SEL from the control unit 110, respectively. The output terminal 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 is coupled to the output of the AND gate 311.

The second shift register unit 220 includes a logic gate (and the gate 321 and the reverse gate 323) and the shift register 322, and the two inputs of the gate 321 receive the data clock signal DCK from the control unit 110, respectively. With the output of the inverting gate 323, the input of the inverting gate 323 is coupled to the path selection signal SEL. The output of the gate 321 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 is coupled to the output of the AND gate 321 .

It can be seen from the above circuit architecture that when the path selection signal SEL is at a logic high level, the first shift temporary storage unit 210 performs data update, and the second shift temporary storage unit 220 does not perform data update; when the path selection signal is SEL is logical When the low potential is recorded, the second shift temporary storage unit 220 performs data update, and the first shift temporary storage unit 210 does not perform data update.

With the path selection signal SEL, the first shift register unit 210 and the second shift register unit 220 can capture the brightness setting data in the data input signal DIN at different timings. Moreover, the first shift temporary storage unit 210 and the second shift temporary storage 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 illustrates the data input signal DIN, the data clock signal DCK, the switching signal SW, the enable signal EN, the inverted enable signal ENB, the path selection signal SEL, the second clock signal CLK2, and the first clock signal. CLK1, the timing relationship between the latch 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 register unit 210 captures the values of the plurality of high-order MSBs (for example, the fifth bit) in the plurality of brightness setting data by the data input signal DIN. Then, when the waveform 411 of the path selection signal SEL is switched to the waveform 412 of the low level, the second shift register unit 220 extracts a plurality of low-order LSBs in the plurality of brightness setting data by the data input signal DIN (for example, 1 bit) value. Then, the latch signal LAT generates an enable pulse 413 for causing the data storage unit 240 to retrieve the values of the plurality of high order MSBs 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 outputs the values of the plurality of low-order LSBs stored in the second shift temporary storage unit 220.

The enable waveform 415 (high level) of the enable signal EN causes the drive unit 260 to drive the light emitting diode 101 according to the values of the plurality of low order LSBs stored in the second shift register unit 220. At this time, the path selection signal SEL is switched to the high level waveform 416, so that the first shift register unit 210 performs data update. then, The waveform 418 of the output selection signal SOUT is correspondingly switched to the high level, so that the output selection unit 240 outputs the value stored in the data storage unit 240 to the driving unit 260, and then the enable signal EN is switched to the high level enable waveform 417, so that The driving unit 260 drives the light emitting diode 101 according to the values of the plurality of high order MSBs stored in the material storage unit 240. By analogy, the LED driving circuit 120 can continuously update the data and drive the LED according to the new data.

It should be noted that the above waveforms are only one embodiment of the circuit of the embodiment, and the enabling level of each signal may be determined according to design requirements. According to the description of the above embodiments, those skilled in the art should The remaining implementations can be easily inferred and will not be described here.

In addition, it is to be noted that the coupling relationship between the above elements includes a direct or indirect electrical connection as long as the desired electrical signal transfer function can be achieved, and the invention is not limited. The technical means in the above embodiments may be combined or used alone, and the components may be added, removed, adjusted or replaced according to their functions and design requirements, and the invention is not limited. After the description of the above embodiments, those skilled in the art should be able to deduce the embodiments thereof, and no further details are provided herein.

In summary, the architecture of the LED driving circuit of the embodiment of the present invention can simultaneously store different bit values in multiple brightness setting data, so that the driving circuit can utilize multiple bit values in the same driving cycle. To drive, thereby improving the utilization ratio of the LED and the update rate of the screen.

Although the embodiments of the present invention have been disclosed as above, the present invention is not limited to the above-described embodiments, and those skilled in the art can make some modifications without departing from the scope of the present invention. The scope of protection of the present invention is therefore defined by the scope of the appended claims.

100‧‧‧ drive system

101‧‧‧Lighting diode

110‧‧‧Control unit

120‧‧‧Lighting diode drive circuit

210‧‧‧First shift register unit

220‧‧‧Second shift register unit

230‧‧‧Path selection unit

240‧‧‧ data storage unit

250‧‧‧Output selection unit

260‧‧‧ drive unit

310‧‧‧Signal generating unit

311, 321‧‧‧ and gate

312, 322‧‧‧ shift register

323‧‧‧Reverse brake

351~35P‧‧‧ and gate

361~36P‧‧‧ drive output circuit

411~418‧‧‧ waveform

OUT1~OUTP‧‧‧ output

SOUT‧‧‧ output selection signal

CLK1‧‧‧ first clock signal

CLK2‧‧‧ second clock signal

DIN‧‧‧ data input signal

DO‧‧‧ data output signal

DCK‧‧‧ data clock signal

LAT‧‧‧Latch signal

EN‧‧‧Enable signal

ENB‧‧‧inverting enable signal

SEL‧‧‧path selection signal

SW‧‧‧Switching signal

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

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

FIG. 3A is a circuit diagram of a light emitting diode driving circuit 120 according to an embodiment of the present invention.

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

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

210‧‧‧First shift register unit

220‧‧‧Second shift register unit

230‧‧‧Path selection unit

240‧‧‧ data storage unit

250‧‧‧Output selection unit

260‧‧‧ drive unit

DIN‧‧‧ data input signal

LAT‧‧‧Latch signal

EN‧‧‧Enable signal

SEL‧‧‧path selection signal

SOUT‧‧‧ output selection signal

OUT1~OUTP‧‧‧ output

DO‧‧‧ data output signal

Claims (12)

The invention relates to a light-emitting diode driving circuit, which is suitable for driving at least one light-emitting diode, comprising: a first shift temporary storage unit for receiving one of the first data in a brightness setting data; and a second shifting temporary storage a unit for receiving a second data in a brightness setting data; a path selecting unit coupled to the first shift register unit and the second shift register unit, and switching to the path according to a path selection signal An output of the first shift register unit or an output of the second shift register unit; a data storage unit coupled to the first shift register unit, storing the first shift temporary according to a latch signal The first data in the memory; an output selection unit coupled to the data storage unit and the second shift temporary storage unit, and selectively outputting the value stored in the data storage unit or the second according to an output selection signal a value stored in the temporary storage unit; and a driving unit coupled to the output selecting unit, determined according to the value stored by the data storage unit, the value stored by the second shift temporary storage unit, and the consistent energy signal The luminescence A light emission time of the polar body. The illuminating diode driving circuit of claim 1, wherein the first shifting temporary storage unit and the second shifting temporary storage unit respectively extract the brightness from the brightness setting value according to the path selection signal. The first information and the second information. The illuminating diode driving circuit of claim 1, wherein the path selection signal, the output selection signal and the latch signal are generated by an internal circuit. The light-emitting diode driving circuit according to claim 1, The driving unit includes at least one logic gate and a driving output circuit. The two input ends of the logic gate are respectively coupled to the output of the enable signal and the output selection unit, and the output end of the logic gate is coupled to the driving output. Circuit. The illuminating diode driving circuit of claim 1, further comprising: a signal generating unit coupled to the output selecting unit, the path selecting unit and the data storage unit, the signal generating unit switching according to a The combination of the signal and the enable signal outputs the path select signal, the output select signal, and the latch signal. The illuminating diode driving circuit of claim 1, further comprising: a signal generating unit coupled to the output selecting unit, the path selecting unit and the data storage unit, the signal generating unit switching according to a The combination of the signal and a data clock signal outputs the path selection signal, the output selection signal, and the latch signal. The illuminating diode driving circuit of claim 1, wherein the second shift register unit can perform data update when the output selecting unit selects and outputs the data storage unit, the first shift temporary storage The unit may update the data after the data storage unit retrieves its data. A driving system for a light emitting diode includes: a control unit for outputting a uniform energy signal and a brightness setting data; and a light emitting diode driving circuit coupled to the control unit, the light emitting diode driving circuit The method includes: a first shift temporary storage unit, configured to receive a first data in the brightness setting data; a second shift register unit for receiving a second data in the brightness setting data; a path selecting unit coupled to the first shift register unit and the second shift register unit, according to a path selection signal is switched to the output of the first shift register unit or the output of the second shift register unit; a data storage unit coupled to the first shift register unit, according to a latch signal Storing the first data in the first shift register; an output selecting unit coupled to the data storage unit and the second shift register unit, and selectively outputting the data storage unit according to an output selection signal The stored value or the value stored in the second shift register unit; and a driving unit coupled to the output selecting unit, according to the value stored by the data storage unit, and stored by the second shift register unit The value and the uniformity signal determine a luminescence time of the light-emitting diodes. The driving system of claim 8, wherein the first shift register unit and the second shift register unit respectively extract the first data from the brightness setting value according to the path selection signal The second information. The driving system of claim 8, wherein the control unit outputs a switching signal, the LED driving circuit further includes a signal generating unit coupled to the output selecting unit, the path selecting unit, and The data storage unit outputs the path selection signal, the output selection signal and the latch signal according to the combination of the switching signal and the enable signal. The driving system of claim 8, wherein the control unit can output a switching signal and a data clock signal, the LED driving circuit further comprising a signal generating unit coupled to the output selecting unit The path selection unit and the data storage unit, the signal generation unit outputs the path selection signal and the output selection signal according to the combination of the switching signal and the data clock signal Number with the latch signal. The driving system of claim 8, wherein the second shift register unit can perform data update when the output selecting unit selects and outputs the data storage unit, where the first shift register unit can be The data storage unit retrieves the data and updates the data.