CN109377938A - A kind of constant-current control device of LED display - Google Patents
A kind of constant-current control device of LED display Download PDFInfo
- Publication number
- CN109377938A CN109377938A CN201811367968.2A CN201811367968A CN109377938A CN 109377938 A CN109377938 A CN 109377938A CN 201811367968 A CN201811367968 A CN 201811367968A CN 109377938 A CN109377938 A CN 109377938A
- Authority
- CN
- China
- Prior art keywords
- led
- current
- constant
- voltage
- circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Control Of El Displays (AREA)
- Dc-Dc Converters (AREA)
Abstract
The invention discloses a kind of high-efficiency constant-flow control devices of LED display, comprising: constant-current circuit, the constant-current circuit generate constant current；Sink current type DC/DC voltage regulator circuit, the sink current type DC/DC voltage regulator circuit is when it pours into different electric currents, and voltage is all in stable state.The constant-current circuit is electrically connected to the pressure stabilizing end of the sink current type DC/DC voltage regulator circuit, and electric current flows into sink current type DC/DC voltage regulator circuit via constant-current circuit.
Description
Technical field
The present invention relates to field of LED display, more particularly, to the high-efficiency constant-current control device of LED display.
Background technique
Light-emitting diode LED is widely used in the fields such as illumination, backlight, display.Large screen is realized using LED as pixel
The advantages of display, includes: that brightness is high, operating voltage is low, small power consumption, enlargement, service life are long, impact resistance and performance are stablized, therefore its
Using more and more extensive.
LED display is generally made of one or more LED display modules.Each LED display module may include LED pixel
Array and driving unit for driving LED pixel array.For example, pixel array can be 4*4,16*16,32*32 or 64*64
Pixel array etc..Each pixel can be monochromatic, dual base color or three primary colours (full-color) pixel unit.Monochrome refers to only
A kind of LED pipe of color, mostly Shan Hong color can also use yellow green in certain special occasions；Dual base color pixel unit by red and
Green LED pipe composition；Full color pixel unit is made of red, green and blue LED pipe.The type of full color pixel unit is logical
Often including 2R1G, 2R1G1B, 1R1G1B etc., 2R1G refers to that a pixel unit has 2 red LED pipes and 1 green LED pipe,
2R1G1B refers to that a pixel unit has 2 red LED pipes, 1 green LED pipe and 1 blue led pipe, and 1R1G1B refers to a picture
Plain unit has 1 red LED pipe, 1 green LED pipe and 1 blue led pipe.
Fig. 1 shows a kind of circuit diagram of control circuit of LED display according to prior art
(CN101866613A).As shown in Figure 1, LED display is arranged to make up by M row * N column LED matrix.The control circuit includes that row is translated
Code device 11, line driver 12, row driver 14 and electric discharge device etc..Since the electric conduction pressure drop of the LED pipe of different colours is deposited
In difference, thus in order to ensure all LED pipes can normal luminous, system power supply voltage is usually to ensure highest conducting voltage
The job requirement of blue lamp and set, in this way, for LED lower for other conducting voltages (such as red LED, green LED), just in vain
Many energy are wasted, these energy all consume on constant-current driven chip, cause driving chip temperature excessively high, and influencing chip can
By property.Meanwhile system temperature can also increase with chip cooling, can also extreme influence LED service life.The present invention is exactly by the above institute
The energy for stating waste is recycled to power end by a kind of high efficiency sink current type DC/DC voltage regulator circuit, to reach energy-saving
Purpose.
Summary of the invention
Aiming at the problems existing in the prior art, according to an aspect of the present invention, a kind of LED high-efficiency constant-current drive is provided
Dynamic device, comprising:
Constant-current circuit, the constant-current circuit generate constant current；
Sink current type DC/DC voltage regulator circuit, when the sink current type DC/DC voltage regulator circuit pours into different electric currents, electricity
Pressure is all in stable state.
The constant-current circuit is electrically connected to the pressure stabilizing end of the sink current type DC/DC voltage regulator circuit, and electric current is via Constant Electric Current
Road flows into sink current type DC/DC voltage regulator circuit.
In one embodiment of the invention, the constant-current circuit includes amplifier, adjustment pipe and sampling pipe, the amplification
Device and adjustment pipe form one and follow circuit or scaling circuit, the positive termination reference voltage of amplifier, and negative terminal and adjustment are managed
Source level be connected, the output end of amplifier is connected with the grid for adjusting pipe, adjusts the drain electrode external load of pipe, the drain electrode of sampling pipe
It is connected with the source level of adjustment pipe, the source level of sampling pipe is connected to the pressure stabilizing end of the sink current type DC/DC voltage regulator circuit.
In one embodiment of the invention, the voltage of voltage regulation Vz of the sink current type DC/DC voltage regulator circuit are as follows: Vz=
VPower supply-VF- Vset, wherein VFIt is loaded pressure drop or LED conduction voltage drop, Vset is that pipe drain electrode and sampling pipe source are adjusted in constant-current circuit
The voltage of interpolar.
In one embodiment of the invention, the constant-current circuit includes the first metal-oxide-semiconductor and the second metal-oxide-semiconductor, the first metal-oxide-semiconductor
Grid be connected with the grid of the second metal-oxide-semiconductor, the drain electrode external load of the first metal-oxide-semiconductor, the drain electrode of the second metal-oxide-semiconductor is connected with grid
And offset signal is received, the source level of the first metal-oxide-semiconductor and the second metal-oxide-semiconductor is connected to the pressure stabilizing end of sink current type DC/DC voltage regulator circuit.
In one embodiment of the invention, the voltage of voltage regulation Vz of the sink current type DC/DC voltage regulator circuit are as follows: Vz=
VPower supply-VF- Vset, wherein VFIt is loaded pressure drop or LED conduction voltage drop, Vset is the drain electrode of the first metal-oxide-semiconductor and source electrode in constant-current circuit
Between voltage.
In one embodiment of the invention, the absolute value of the Vset is in the range of 0.01V to 2V.
In one embodiment of the invention, LED high-efficiency constant-current driving device further includes output voltage controller, described
Output voltage controller detects the Vset, and the voltage is made comparisons with the operating voltage of setting, is adjusted based on comparative result
The pressure stabilizing value of the sink current type DC/DC voltage regulator circuit.
In one embodiment of the invention, the sink current type DC/DC voltage regulator circuit includes continued flow tube, switching tube, opens
Driving, PWM/PFM controller, oscillator and amplifier or comparator are closed,
The continued flow tube is N-type MOS transistor, and source level is connected with positive supply VDD, drain and the drain electrode of switching tube and
Output end is connected, and grid is connected to switch driving；
The switching tube is N-type MOS transistor, and source level ground connection drains and is connected with the drain electrode of continued flow tube and output end,
Its grid is connected to switch driving；
The amplifier or the voltage and reference voltage at comparator acquisition pressure stabilizing end, and the two comparison result is output to
PWM/PFM controller；
The PWM/PFM controller is generated according to the output of the output signal and oscillator of amplifier or comparator and is controlled
Signal is simultaneously supplied to switch driving.
In one embodiment of the invention, the sink current type DC/DC voltage regulator circuit includes continued flow tube, switching tube, opens
Driving, PWM/PFM controller, oscillator and amplifier or comparator are closed,
The continued flow tube is Schottky diode, and cathode is connected with positive supply VDD, the drain electrode of anode and switching tube and
Output end is connected；
The switching tube is N-type MOS transistor, and source level ground connection, grid, which is connected to, switchs driving；
The amplifier or the voltage and reference voltage at comparator acquisition pressure stabilizing end, and the two comparison result is output to
PWM/PFM controller；
The PWM/PFM controller is generated according to the output of the output signal and oscillator of amplifier or comparator and is controlled
Signal is simultaneously supplied to switch driving.
In one embodiment of the invention, the pressure stabilizing end of the sink current type DC/DC voltage regulator circuit passes through capacity earth
Or power supply, inductor is accessed between the output end and pressure stabilizing end of the sink current type DC/DC voltage regulator circuit.
In one embodiment of the invention, the sink current type DC/DC voltage regulator circuit, electric current is by sink current at work
The voltage regulator circuit pressure stabilizing end type DC/DC flows into, and by inductor, or flows into ground terminal by switching tube or flows into electricity by continued flow tube
Source.
In one embodiment of the invention, the red LED that the LED constant current driving device is included in LED display arranges
In driver.
In one embodiment of the invention, the green LED that the LED constant current driving device is included in LED display arranges
In driver.
In one embodiment of the invention, the LED display includes the array of M row, N column LED pipe composition, described
LED constant current driving device drives a column LED pipe, and the anode interconnection of every a line LED pipe constitutes common anode configuration.
In one embodiment of the invention, the anode of the LED pipe is connected to power supply, the cathode and perseverance of the LED pipe
Current circuit is connected.
Detailed description of the invention
For the above and other advantages and features for each embodiment that the present invention is furture elucidated, will be presented with reference to attached drawing
The more specific description of various embodiments of the present invention.It is appreciated that these attached drawings only describe exemplary embodiments of the invention, therefore
It is not to be regarded as being restriction on its scope.In the accompanying drawings, in order to cheer and bright, identical or corresponding component will use identical or class
As mark indicate.
Fig. 1 shows a kind of circuit diagram of control circuit of LED display according to prior art.
Fig. 2 shows a kind of circuit diagrams of LED display system 200.
Fig. 3 A shows the circuit diagram of LED display system 300 according to an embodiment of the invention.
Fig. 3 B shows the schematic diagram of LED display system according to another embodiment of the invention.
Fig. 4 A shows the circuit of high efficiency sink current type DC/DC voltage regulator circuit 400 according to an embodiment of the invention
Schematic diagram.
Fig. 4 B shows the electric current signal of high efficiency sink current type DC/DC voltage regulator circuit according to an embodiment of the invention
Figure.
Fig. 4 C shows the circuit diagram of sink current type DC/DC voltage regulator circuit according to another embodiment of the invention.
Fig. 4 D shows the circuit diagram of sink current type DC/DC voltage regulator circuit according to another embodiment of the invention.
Fig. 5 shows the circuit diagram of LED display system 500 according to an embodiment of the invention.
Fig. 6 is shown according to one embodiment of present invention in the constant current driver circuit for LED using load resistance.
Fig. 7 shows permanent in the LED using high efficiency sink current type DC/DC voltage regulator circuit according to one embodiment of present invention
Flow driving circuit.
Specific embodiment
In the following description, with reference to each embodiment, present invention is described.However, those skilled in the art will recognize
Know can in the case where none or multiple specific details or with other replacements and/or addition method, material or component
Implement each embodiment together.In other situations, well known structure, material or operation are not shown or are not described in detail in order to avoid making this
The aspects of each embodiment of invention is obscure.Similarly, for purposes of explanation, specific quantity, material and configuration are elaborated, with
Comprehensive understanding to the embodiment of the present invention is just provided.However, the present invention can be implemented in the case where no specific detail.This
Outside, it should be understood that each embodiment shown in the accompanying drawings is illustrative expression and is not drawn necessarily to scale.
In the present specification, the reference of " one embodiment " or " embodiment " is meaned to combine embodiment description
A particular feature, structure, or characteristic is included at least one embodiment of the invention.Occur in everywhere in this specification short
Language " in one embodiment " is not necessarily all referring to the same embodiment.
Fig. 2 shows a kind of LED display systems 200.LED display system may include several rows and several columns LED pixel array,
And it is arranged in a manner of matrix.For ease of description, in the present embodiment, as shown in Fig. 2, showing a line LED, and row is omitted
Driving circuit, but scope of protection of the present invention is not limited thereto.Each LED pixel includes one red LED pipe 211, one
Green LED pipe 212 and a blue led pipe 213.The anode of every row LED pipe is commonly connected to power vd D, constitutes common anode configuration.
The each column LED pipe of LED array is connected to respective constant current row driver according to color classification.Specifically, each column red LED
The cathode of pipe connect and is controlled by it with red LED constant current row driver 220；The cathode and green LED of each column green LED pipe
Constant current row driver 230 is connected and is controlled by it；The cathode and blue led constant current row driver 240 of each column blue led pipe connect
It connects and is controlled by it.
In LED display system 200, the circuit structure inside red LED constant current row driver 220, green LED are shown
The circuit structure of constant current row driver 230 and blue led constant current row driver 240 and 220 class of red LED constant current row driver
Seemingly, to simplify the description, only red LED constant current row driver 220 is illustrated herein, those skilled in the art is based on should
Illustrate the circuit structure and the work side that understand that green LED constant current row driver 230 and blue led constant current row driver 240
Formula.
The anode of red LED pipe 211 connects power end, and the cathode of red LED pipe 211 connects the driving end of row driver 220, column
Driver 220 includes column drive control circuit 221 and constant-current circuit 222.Constant-current circuit 222 as shown in the figure include amplifier 223,
Adjust pipe 224 and sampling pipe 225.Adjustment pipe 224 can be N-type MOS transistor.Sampling pipe 225 can be N-type MOS transistor.
Equivalent sampling resistance of the sampling pipe 225 as constant-current circuit, amplifier 223 and adjustment pipe 224 form one and follow circuit or ratio
The source voltage terminal of example amplifying circuit, adjustment pipe 224 is equal to amplifier anode reference voltage, then the electric current of sampling pipe 225 are as follows: reference
The resistance of voltage/sampling pipe 225.The electric current for similarly flowing into adjustment 224 drain terminal of pipe is the resistance of reference voltage/sampling pipe 225, electricity
Circulate toning homogeneous tube 224 and the inflow ground terminal of sampling pipe 225.
In LED display system shown in Fig. 2, the LED pipe of various colors is all connected to the same power supply, and supplies
To identical voltage.However the conducting voltage of red LED pipe is reduced to the electric conduction pressure drop of green and blue LED pipe.If will
Identical supply voltage is applied in red, green and blue LED pipe, in order to match the electric conduction pressure drop of each LED pipe, power supply electricity
Pressure will be based on meeting voltage needed for blue lamp.For example, the electric conduction pressure drop of red LED pipe is generally 2.0V, blue led pipe
Conduction voltage drop is 3.0 between 3.3V.So in order to ensure that all LED pipes and its constant current row driver all work normally, power supply
VDD needs to meet VDD >=VF is blue+ Vset, wherein VF is blueIt is the conduction voltage drop of blue led pipe, VSetIt is that pipe leakage is adjusted in constant-current circuit
Voltage between pole and sampling pipe source electrode.In general, the Vset of constant current driving can be worked normally in 0.4V or so.Blue lamp is normal at this time
Minimum voltage needed for working should be VDD=3.3+0.4=3.7V, it is contemplated that engineering surplus and nominal value, in practical applications, electricity
Source VDD selects 5V normal voltage.
For red LED pipe, voltage needed for working normally is VddRed=VF is red+VSet=2.0+0.4=2.4V.As power vd D
Voltage be 5V when, there is 2.6V excess voltage to need to consume, be typically employed between power supply and each red LED connect one
Load resistance is come the extra power consumption that dissipates.In this case, a large amount of energy will be wasted on load resistance as heat.
Specifically, it is contemplated that the current ratio of red LED pipe accounts for 50% of total current or more, so red LED guard system is disappeared
The power of consumption also accounts for 50% or more of overall system power.The waste power of red LED guard system is Pc=(VDD-VddIt is red)IIt is red=
(5-2.4)*IRed=2.6*IIt is red, and total output power Pd=VDD*I of red light systemIt is red, the power supply efficiency of red light system is n at this time
=(Pd-Pc)/Pd=(5-2.6) IIt is red/5IIt is red=48%.About 52% energy is wasted.
For energy conservation, another scheme is that the LED pipe that LED display system is different colours provides different power supply electricity respectively
Pressure.In other words, the power supply of red LED pipe and the power supply of blue and green LED pipe are separated, this needs two-way power supply power supply.
As LED display requires pel spacing lower and lower, two-way power supply power supply, wiring is almost difficult to realize.Meanwhile low-voltage
AC/DC power supply cost be 5V power supply 2 times or more.Moreover, the own efficiency of low-voltage AC/DC power supply is also difficult to mention
It is high.
In an embodiment of the present invention, increase sink current type DC/DC voltage regulator circuit in red LED constant current row driver,
Excess voltage on red LED pipe circuit is subjected to voltage transformation, rather than is divided by load resistance.Sink current type
The own efficiency of DC/DC voltage regulator circuit can be more than 90%.In this way, the waste power of red LED guard system is by original Pc=
(VDD-VddIt is red)IIt is red=(5-2.4) * IRed=2.6*IIt is red, it is reduced to Pc=2.6*IIt is red* 10%=0.26*IIt is red.Red light system at this time
Power supply efficiency is upgraded to n=(Pd-Pc)/Pd=(5-2.6*10%) IIt is red/5*IIt is red=95%.
In view of above-mentioned red LED guard system consumption power accounts for 50% or more of overall system power, if only red LED
Guard system uses sink current type DC/DC voltage regulator circuit, then overall system efficiency (not considering blue, green LED lamp system) will be by original
N=(1+48%)/2=74% be increased to n=(1+95%)/2=98%, total system power supply efficiency (does not consider blue, green LED
Lamp system) 24% will be improved.
If also using sink current type DC/DC voltage regulator circuit in blue, green LED system, gross efficiency can also be mentioned greatly
It rises.
Fig. 3 A shows the schematic diagram of LED display system 300 according to an embodiment of the invention.LED display system can
Comprising several row LED pixel arrays, and arranged in a manner of matrix.For ease of description, in the present embodiment, such as Fig. 3 A institute
Show, a line LED is shown, and horizontal drive circuit is omitted, but scope of protection of the present invention is not limited thereto.Each LED pixel
Including 310, green LED pipes 311 of a red LED pipe and a blue led pipe 312.The anode of every row LED pipe connects jointly
It is connected to power vd D, constitutes common anode configuration.The each column LED pipe of LED array is connected to respective constant current column driving according to color classification
Device.Specifically, the cathode of each column red LED pipe connect and is controlled by it with red LED constant current row driver 320；It is each
The cathode of column green LED pipe connect and is controlled by it with green LED constant current row driver 330；The cathode of each column blue led pipe
It connect and is controlled by it with blue led constant current row driver 340.
In the LED display system shown in Fig. 3 A, the LED pipe of various colors is all connected to the same power supply, and
Supply identical voltage.In order to ensure that all LED pipes and its constant current row driver all work normally, power vd D needs to meet VDD
≥VF is blue+VSet, wherein VF is blueIt is the conduction voltage drop of blue led pipe, VSetIt is to be adjusted in constant-current circuit between pipe drain electrode and sampling pipe source electrode
Voltage.Increase high efficiency sink current type DC/DC voltage regulator circuit 321 in the ground terminal of red LED constant current row driver 320.It fills
Current mode DC/DC voltage regulator circuit 321 carries out voltage transformation, so that the output voltage V of sink current type DC/DC voltage regulator circuitZAre as follows: VZ
=VPower supply-VF is red- Vset, wherein VF is redIt is the pressure drop of red LED pipe, Vset is that pipe drain electrode and sampling pipe are adjusted in constant-current control circuit
Voltage between source electrode.Vset is typically set at 0.4V or so.Specifically, as shown in Figure 3A, red LED constant current row driver
320 include sink current type DC/DC voltage regulator circuit 321, column drive control circuit 322 and constant-current circuit 323.Constant-current circuit 323 wraps
Include adjustment pipe 324, sampling pipe 325 and amplifier or comparator 326.Adjustment pipe 324 and sampling pipe 325 can be NMOS crystal
Pipe.The pressure stabilizing end of sink current type DC/DC voltage regulator circuit 321 is connected with the source electrode of sampling pipe 325, sink current type DC/DC pressure stabilizing electricity
Road 321 is also connected by capacitor Cout with ground terminal.Equivalent sampling resistance of the sampling pipe 325 as constant-current circuit, amplifier or
Comparator 326 and adjustment pipe 324 form one and follow circuit or scaling circuit, the positive termination of amplifier or comparator 326
Reference voltage is received, negative terminal is connected with the source level of adjustment pipe 324, the output end of amplifier or comparator 326 and the grid of adjustment pipe
It is connected.The drain electrode of sampling pipe 325 is connected with the source level of adjustment pipe 324.At this point, continuous current are as follows: reference voltage-VZ/ sampling pipe
325 equivalent resistance.Electric current flows into sink current type DC/DC voltage regulator circuit 321 by adjusting pipe 324 and sampling pipe 325.
Although Vset is usually operated at 0.4V or so, absolute value can in the range of 0.01V to 2V, this voltage by
It is related with the metal-oxide-semiconductor design conducting resistance of sampling pipe 325 to adjust pipe 324, the conducting resistance for adjusting pipe 324 and sampling pipe 325 is set
Count smaller, the minimum of constant-current circuit is smaller.The source of sampling pipe 325 is raised by sink current type DC/DC voltage regulator circuit
The voltage at end makes constant-current circuit work near minimum.
Fig. 3 B shows the schematic diagram of LED display system according to another embodiment of the invention.With system shown in Fig. 3 A
The difference is that sampling pipe 325 is resistance.
Fig. 4 A shows the circuit diagram of sink current type DC/DC voltage regulator circuit 400 according to an embodiment of the invention.
As shown in Figure 4 A, the pressure stabilizing end 401 of sink current type DC/DC voltage regulator circuit 400 is connected with sampling pipe.Sink current type DC/DC pressure stabilizing
Circuit 400 is a kind of electric pressure converter that can export fixed voltage.Pressure stabilizing end 401 is grounded or is connect power supply by capacitor Cout.
Sink current type DC/DC voltage regulator circuit 400 includes continued flow tube 410, switching tube 420, switch driving 440, PWM/PFM controller
450, oscillator 460 and amplifier or comparator 470.
Continued flow tube 410 is N-type MOS transistor, and source level is connected with power vd D anode, the leakage of drain electrode and switching tube 420
Pole and output end are connected, and grid is connected to switch driving 440.Switching tube 420 is N-type MOS transistor, and source level is grounded,
Drain electrode is connected with the drain electrode of continued flow tube 410 and output end, and grid is connected to switch driving 440.Amplifier or comparator 470 are adopted
The voltage at sample pressure stabilizing end receives reference voltage, and comparison result is output to PWM/PFM controller 450.PWM/PFM controller
450 generate control signal according to the output of the output signal and oscillator 460 of amplifier or comparator 470 and are supplied to switch
Driving 440.
Inductor 430 is connected between output end and pressure stabilizing end.
Fig. 4 B shows the current diagram of sink current type voltage regulator circuit according to an embodiment of the invention.Firstly, coming
It can charge from the electric current Is of constant-current circuit to Cout, pressure stabilizing end voltage Vz is constantly increased, and when Vz voltage is greater than setting voltage, is opened
It closes pipe 420 to be connected, the charge that Cout is kept at this time is discharged over the ground by inductance 430, and current direction is as shown by arrow A.Meanwhile it putting
Electric current will be in 430 storage energy of inductance, after inductance 430 stores certain energy, and switching tube 420 turns off, while afterflow
Pipe 410 is connected.The energy of inductor storage will be back to power end by continued flow tube 410 (current direction is as shown in arrow II).
One switch periods terminates, and starts switching tube 420 to next cycle and is connected again again to inductor energy storage, so recycles.This
Sample, energy caused by continuous current Is stores in the inductor mostly and is sent back to power end, directly by resistance heat loss
Energy is very low, this can be so that the efficiency of sink current type DC/DC voltage regulator circuit be increased to 90% or more.
Amplifier or comparator 470 detect pressure stabilizing end voltage, and by it compared with reference voltage.When pressure stabilizing end, voltage is greater than
When reference voltage, increase the turn-on time of switching tube 420, the upper excess energy of Cout is more stored on inductance.When pressure stabilizing end
When voltage is less than reference voltage, reduce 420 turn-on time of switching tube, energy is supplemented to Cout by continuous current Is.It is reached with this
Pressure stabilizing end voltage stabilization is being set in voltage range to dynamic equilibrium.
Fig. 4 C shows the circuit diagram of sink current type DC/DC voltage regulator circuit according to another embodiment of the invention.
With circuit shown in Fig. 4 A the difference is that constant-current circuit is mirror current source.The constant-current circuit includes two metal-oxide-semiconductors (or three
Pole pipe), the grid of the first metal-oxide-semiconductor 480 is connected with the grid of the second metal-oxide-semiconductor 490.The drain electrode of first metal-oxide-semiconductor 480 and LED pipe
Cathode is connected.The drain electrode of second metal-oxide-semiconductor 490 is connected with grid and receives offset signal.First metal-oxide-semiconductor 480 and the second metal-oxide-semiconductor
490 source level is connected to the pressure stabilizing end of sink current type DC/DC voltage regulator circuit.Vset is the first metal-oxide-semiconductor 480 in constant-current control circuit
Voltage between drain electrode and source electrode.The absolute value of Vset can be in the range of 0.01V to 2V.
Fig. 4 D shows the circuit diagram of sink current type DC/DC voltage regulator circuit according to another embodiment of the invention.
With circuit shown in Fig. 4 A the difference is that continued flow tube 410 is Schottky diode, the anode and switch of Schottky diode
The drain electrode of pipe 420 is connected, and the cathode of Schottky diode is connected to power vd D.
Fig. 5 shows 500 schematic diagram of LED display system according to an embodiment of the invention.For ease of description, at this
In embodiment, as shown in figure 5, showing a LED pipe 510, horizontal drive circuit and column drive control circuit, but the present invention is omitted
Protection scope be not limited thereto.510 anode of LED pipe is connected to supply voltage VDD, and 510 cathode of LED pipe is connected to Constant Electric Current
Road 520.The other end of constant-current circuit 520 is connected to the pressure stabilizing end of sink current type DC/DC voltage regulator circuit 530.Output voltage control
The voltage drop of the detection constant-current circuit 520 of device 540.In other words, the adjustment pipe and sampling pipe of constant-current circuit are determined by subtracter 541
Voltage difference, that is, Vset, this voltage difference is made comparisons with the minimum of setting, by comparing result control sink current
The pressure stabilizing end voltage of type DC/DC voltage regulator circuit.So that the voltage difference Vset of adjustment pipe and sampling pipe is in minimum work electricity always
Near pressure.No matter how input voltage, which changes entire driving circuit, in this way can work in most efficient state.
In the above-described embodiments, sink current type DC/DC voltage regulator circuit is connected between ground terminal and constant-current circuit, however,
It should be appreciated by those skilled in the art in some embodiments of the invention, sink current type DC/DC voltage regulator circuit can be arranged
In the other positions of circuit.
It is permanent using load resistance and using the LED of sink current type DC/DC voltage regulator circuit below with reference to one embodiment comparison
Flow the efficiency of driving circuit.Fig. 6, which is shown, is driving electricity using the LED constant current of load resistance according to one embodiment of present invention
Road.Assuming that LED pipe 610 is red LED pipe, supply voltage VDD is 5V.Constant-current circuit includes adjustment pipe 620, resistance 630 and puts
Big device 640.Load resistance 650 is connected between resistance 630 and ground terminal.Assuming that the forward voltage drop V of LED pipe 610FFor 2V, then
Voltage V at 610 cathode of LED pipe0For 3V.The voltage for maintaining constant-current circuit to work normally only needs 0.3 to 0.4V.Therefore, it loads
Voltage Vs at resistance 650 and 630 connecting node of resistance is 2.6V, and the power consumption that this 2.6V voltage generates belongs to waste power consumption.
Assuming that the circuit in load resistance 650 is IL, the power consumption of waste is Pn=IL*Vs.Actual efficiency are as follows:
It can be seen that consuming the power consumption of more than half on load resistance.
Fig. 7 shows permanent in the LED using high efficiency sink current type DC/DC voltage regulator circuit according to one embodiment of present invention
Flow driving circuit.Difference with circuit shown in Fig. 6 is that sink current type DC/DC voltage regulator circuit 710 replaces load resistance 650, benefit
52% power consumption of waste is collected with sink current type DC/DC voltage regulator circuit 710, power end is returned to by T2 pipe again.Due to
The transfer efficiency of this conversion regime can reach or more than 90%, at this time the actual efficiency of circuit are as follows:
In the above embodiment of the present invention, it is introduced by taking the column drive circuit of a column LED as an example.However, this field
It is to be understood by the skilled artisans that sink current type DC/DC pressure stabilizing electricity can be increased in each column drive circuit of LED display system
Road.For example, sink current type DC/DC voltage regulator circuit can be increased in green LED constant current row driver.In this way, in supply voltage
When for 5V, comprehensive power consumption can reduce by 30% or more.In addition, in some embodiments of the invention, in the LED constant current of each color
Increase sink current type DC/DC voltage regulator circuit in row driver, the supply voltage of system can be improved in this way, system power source voltage mentions
The total current of system power supply can reduce after height, so as to reduce the line loss of system.
Although described above is various embodiments of the present invention, however, it is to be understood that they are intended only as example to present
, and without limitation.For those skilled in the relevant art it is readily apparent that various combinations, modification can be made to it
Without departing from the spirit and scope of the invention with change.Therefore, the width of the invention disclosed herein and range should not be upper
It states disclosed exemplary embodiment to be limited, and should be defined according only to the appended claims and its equivalent replacement.
Claims (15)
1. a kind of LED high-efficiency constant-current driving device, comprising:
Constant-current circuit, the constant-current circuit generate constant current；
Sink current type DC/DC voltage regulator circuit, when the sink current type DC/DC voltage regulator circuit pours into different electric currents, voltage is all
In stable state.
The constant-current circuit is electrically connected to the pressure stabilizing end of the sink current type DC/DC voltage regulator circuit, and electric current is via constant-current circuit stream
Enter sink current type DC/DC voltage regulator circuit.
2. LED high-efficiency constant-current driving device as described in claim 1, which is characterized in that the constant-current circuit includes amplification
Device, adjustment pipe and sampling pipe, the amplifier and adjustment pipe form one and follow circuit or scaling circuit, and amplifier is just
Reference voltage is terminated, negative terminal is connected with the source level of adjustment pipe, and the output end of amplifier is connected with the grid of adjustment pipe, adjusts pipe
Drain external load, and the drain electrode of sampling pipe is connected with the source level of adjustment pipe, and the source level of sampling pipe is connected to the sink current type DC/
The pressure stabilizing end of DC voltage regulator circuit.
3. LED high-efficiency constant-current driving device as claimed in claim 2, which is characterized in that the sink current type DC/DC pressure stabilizing
The voltage of voltage regulation Vz of circuit are as follows: Vz=VPower supply-VF- Vset, wherein VFIt is loaded pressure drop or LED conduction voltage drop, Vset is Constant Electric Current
The voltage between pipe drain electrode and sampling pipe source electrode is adjusted in road.
4. LED high-efficiency constant-current driving device as described in claim 1, which is characterized in that the constant-current circuit includes first
Metal-oxide-semiconductor and the second metal-oxide-semiconductor, the grid of the first metal-oxide-semiconductor are connected with the grid of the second metal-oxide-semiconductor, and the drain electrode of the first metal-oxide-semiconductor is external negative
It carries, the drain electrode of the second metal-oxide-semiconductor is connected with grid and receives offset signal, and the source level of the first metal-oxide-semiconductor and the second metal-oxide-semiconductor is connected to filling
The pressure stabilizing end of current mode DC/DC voltage regulator circuit.
5. LED high-efficiency constant-current driving device as claimed in claim 4, which is characterized in that the sink current type DC/DC pressure stabilizing
The voltage of voltage regulation Vz of circuit are as follows: Vz=VPower supply-VF- Vset, wherein VFIt is loaded pressure drop or LED conduction voltage drop, Vset is Constant Electric Current
Voltage in road between the drain electrode of the first metal-oxide-semiconductor and source electrode.
6. LED high-efficiency constant-current driving device as claimed in claim 3 or 5, which is characterized in that the absolute value of the Vset exists
In the range of 0.01V to 2V.
7. LED high-efficiency constant-current driving device as claimed in claim 3 or 5, which is characterized in that further include output voltage control
Device, the output voltage controller detect the Vset, the voltage are made comparisons with the operating voltage of setting, are tied based on comparing
Fruit adjusts the pressure stabilizing value of the sink current type DC/DC voltage regulator circuit.
8. LED high-efficiency constant-current driving device as described in claim 1, which is characterized in that the sink current type DC/DC pressure stabilizing
Circuit includes continued flow tube, switching tube, switchs driving, PWM/PFM controller, oscillator and amplifier or comparator,
The continued flow tube is N-type MOS transistor, and source level is connected with positive supply VDD, the drain electrode and output of drain electrode and switching tube
End is connected, and grid is connected to switch driving；
The switching tube is N-type MOS transistor, and source level ground connection drains and is connected with the drain electrode of continued flow tube and output end, grid
Pole is connected to switch driving；
The amplifier or the voltage and reference voltage at comparator acquisition pressure stabilizing end, and the two comparison result is output to PWM/
PFM controller；
The PWM/PFM controller generates control signal according to the output of the output signal and oscillator of amplifier or comparator
And it is supplied to switch driving.
9. LED high-efficiency constant-current driving device as described in claim 1, which is characterized in that the sink current type DC/DC pressure stabilizing
Circuit includes continued flow tube, switching tube, switchs driving, PWM/PFM controller, oscillator and amplifier or comparator,
The continued flow tube is Schottky diode, and cathode is connected with positive supply VDD, the drain electrode and output of anode and switching tube
End is connected；
The switching tube is N-type MOS transistor, and source level ground connection, grid, which is connected to, switchs driving；
The amplifier or the voltage and reference voltage at comparator acquisition pressure stabilizing end, and the two comparison result is output to PWM/
PFM controller；
The PWM/PFM controller generates control signal according to the output of the output signal and oscillator of amplifier or comparator
And it is supplied to switch driving.
10. LED high-efficiency constant-current driving device as claimed in claim 8 or 9, which is characterized in that the sink current type DC/DC
The pressure stabilizing end of voltage regulator circuit passes through capacity earth or power supply, output end and the pressure stabilizing end of the sink current type DC/DC voltage regulator circuit
Between access inductor.
11. LED high-efficiency constant-current driving device as claimed in claim 10, which is characterized in that the sink current type DC/DC is steady
Volt circuit, electric current is flowed by the sink current voltage regulator circuit pressure stabilizing end type DC/DC at work, by inductor, or passes through switching tube
It flows into ground terminal or flows into power end by continued flow tube.
12. LED high-efficiency constant-current driving device as described in claim 1, which is characterized in that the LED constant current driving device
Included in the red LED row driver of LED display.
13. LED high-efficiency constant-current driving device as described in claim 1, which is characterized in that the LED constant current driving device
Included in the green LED row driver of LED display.
14. LED high-efficiency constant-current driving device as described in claim 1, which is characterized in that the LED display includes M
The array that row, N column LED pipe are constituted, the LED constant current driving device drive a column LED pipe, and the anode of every a line LED pipe interconnects,
Constitute common anode configuration.
15. LED high-efficiency constant-current driving device as claimed in claim 14, which is characterized in that the anode of the LED pipe connects
Cathode to power supply, the LED pipe is connected with constant-current circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811367968.2A CN109377938B (en) | 2018-11-16 | 2018-11-16 | Constant current control device of LED display screen |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811367968.2A CN109377938B (en) | 2018-11-16 | 2018-11-16 | Constant current control device of LED display screen |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109377938A true CN109377938A (en) | 2019-02-22 |
| CN109377938B CN109377938B (en) | 2023-08-08 |
Family
ID=65389324
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811367968.2A Active CN109377938B (en) | 2018-11-16 | 2018-11-16 | Constant current control device of LED display screen |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109377938B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110288941A (en) * | 2019-07-22 | 2019-09-27 | 深圳蓝普科技有限公司 | A kind of common-anode LED display energy conservation method of supplying power to and circuit |
| JP2020166265A (en) * | 2019-03-28 | 2020-10-08 | 聚積科技股▲ふん▼有限公司 | Display system and drive circuit of display system |
| TWI803341B (en) * | 2021-08-19 | 2023-05-21 | 群創光電股份有限公司 | Electronic device |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001215913A (en) * | 2000-02-04 | 2001-08-10 | Toko Inc | Lighting circuit |
| US20090066264A1 (en) * | 2007-09-12 | 2009-03-12 | Chaogang Huang | High-voltage high-power constant current led driver device |
| CN102105007A (en) * | 2010-12-28 | 2011-06-22 | 河海大学常州校区 | LED constant-current driver with boosting function |
| CN202514139U (en) * | 2012-04-09 | 2012-10-31 | 青岛海信电器股份有限公司 | Backlight driving circuit and liquid crystal display |
| CN202818699U (en) * | 2012-08-16 | 2013-03-20 | 重庆雷本光电科技有限公司 | LED automotive headlamp drive circuit |
| CN209070952U (en) * | 2018-11-16 | 2019-07-05 | 上海得倍电子技术有限公司 | A kind of LED high-efficiency constant-current driving device |
-
2018
- 2018-11-16 CN CN201811367968.2A patent/CN109377938B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001215913A (en) * | 2000-02-04 | 2001-08-10 | Toko Inc | Lighting circuit |
| US20090066264A1 (en) * | 2007-09-12 | 2009-03-12 | Chaogang Huang | High-voltage high-power constant current led driver device |
| CN102105007A (en) * | 2010-12-28 | 2011-06-22 | 河海大学常州校区 | LED constant-current driver with boosting function |
| CN202514139U (en) * | 2012-04-09 | 2012-10-31 | 青岛海信电器股份有限公司 | Backlight driving circuit and liquid crystal display |
| CN202818699U (en) * | 2012-08-16 | 2013-03-20 | 重庆雷本光电科技有限公司 | LED automotive headlamp drive circuit |
| CN209070952U (en) * | 2018-11-16 | 2019-07-05 | 上海得倍电子技术有限公司 | A kind of LED high-efficiency constant-current driving device |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2020166265A (en) * | 2019-03-28 | 2020-10-08 | 聚積科技股▲ふん▼有限公司 | Display system and drive circuit of display system |
| US11132940B2 (en) | 2019-03-28 | 2021-09-28 | Macroblock, Inc. | Display system and driving circuit thereof |
| JP7112759B2 (en) | 2019-03-28 | 2022-08-04 | 聚積科技股▲ふん▼有限公司 | DISPLAY SYSTEM AND DRIVE CIRCUIT FOR THE DISPLAY SYSTEM |
| CN110288941A (en) * | 2019-07-22 | 2019-09-27 | 深圳蓝普科技有限公司 | A kind of common-anode LED display energy conservation method of supplying power to and circuit |
| TWI803341B (en) * | 2021-08-19 | 2023-05-21 | 群創光電股份有限公司 | Electronic device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109377938B (en) | 2023-08-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8373346B2 (en) | Solid state lighting system and a driver integrated circuit for driving light emitting semiconductor devices | |
| Chen et al. | A SIMO parallel-string driver IC for dimmable LED backlighting with local bus voltage optimization and single time-shared regulation loop | |
| CN102237038B (en) | Energy-saving method and circuit | |
| CN100524418C (en) | Drive device of light emitting display panel | |
| US8188679B2 (en) | Self-powered LED bypass-switch configuration | |
| US20140118414A1 (en) | Dc-dc converter and organic light emitting display device using the same | |
| CN109360526A (en) | A kind of LED high-efficiency constant-current control device | |
| CN201700054U (en) | Light-emitting diode control circuit with no residual light | |
| CN109377938A (en) | A kind of constant-current control device of LED display | |
| US20090167264A1 (en) | Dc-dc converter usable for dual voltage supply | |
| CN201608947U (en) | LED display device and LED backlight source driving system thereof | |
| CN102316625B (en) | Lighting device and light source control circuit thereof | |
| CN109377939B (en) | High-efficiency LED driving device | |
| CN209070952U (en) | A kind of LED high-efficiency constant-current driving device | |
| CN1831922B (en) | Device and method for driving for light-emitting display panel | |
| CN209070953U (en) | A kind of high efficiency LED drive device | |
| Jiang et al. | Fully-integrated AMLED micro display system with a hybrid voltage regulator | |
| Hsieh et al. | A charge-recycling buck-store and boost-restore (BSBR) technique with dual outputs for RGB LED backlight and flashlight module | |
| CN110708807A (en) | Common-cathode LED driving circuit, chip, display circuit and display method | |
| CN209070954U (en) | A kind of LED high-efficiency constant-current control device | |
| CN102665323B (en) | Driving method, driving circuit and driving method of light emitting diode string | |
| KR101554583B1 (en) | Organic electroluminescent display and method of driving the same | |
| CN102411903B (en) | Light emitting diode (LED) driving device | |
| TWI467548B (en) | Backlight module and driving method thereof | |
| WO2023155226A1 (en) | Pixel circuit and display panel |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |