CN111312154B - AMLED driving method and device - Google Patents
AMLED driving method and device Download PDFInfo
- Publication number
- CN111312154B CN111312154B CN201911122572.6A CN201911122572A CN111312154B CN 111312154 B CN111312154 B CN 111312154B CN 201911122572 A CN201911122572 A CN 201911122572A CN 111312154 B CN111312154 B CN 111312154B
- Authority
- CN
- China
- Prior art keywords
- current
- led
- signal
- terminal
- driving
- 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.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 27
- 238000004146 energy storage Methods 0.000 claims description 43
- 230000009471 action Effects 0.000 claims description 35
- 238000007599 discharging Methods 0.000 claims description 5
- 230000000737 periodic effect Effects 0.000 claims description 5
- 210000004027 cell Anatomy 0.000 claims 10
- 210000000352 storage cell Anatomy 0.000 claims 6
- 230000011664 signaling Effects 0.000 claims 1
- 102100040862 Dual specificity protein kinase CLK1 Human genes 0.000 description 36
- 101000749294 Homo sapiens Dual specificity protein kinase CLK1 Proteins 0.000 description 36
- 230000001276 controlling effect Effects 0.000 description 33
- 102100040844 Dual specificity protein kinase CLK2 Human genes 0.000 description 24
- 101000749291 Homo sapiens Dual specificity protein kinase CLK2 Proteins 0.000 description 24
- 239000003990 capacitor Substances 0.000 description 19
- 238000010586 diagram Methods 0.000 description 8
- 230000001105 regulatory effect Effects 0.000 description 8
- 230000008569 process Effects 0.000 description 6
- 239000006185 dispersion Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 101100328957 Caenorhabditis elegans clk-1 gene Proteins 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 102100036285 25-hydroxyvitamin D-1 alpha hydroxylase, mitochondrial Human genes 0.000 description 1
- 241001270131 Agaricus moelleri Species 0.000 description 1
- 101000875403 Homo sapiens 25-hydroxyvitamin D-1 alpha hydroxylase, mitochondrial Proteins 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
Images
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)
- Led Devices (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
- Control Of El Displays (AREA)
Abstract
The invention relates to an AMLED driving method and device, which are used for driving an LED to display with a target gray value in a working period, wherein the method comprises the following steps: when the target gray value does not exceed the threshold value, controlling the driving current of the LED in the working period to be constant at a preset current value, and controlling the duty ratio of the driving current of the LED in the working period to be a ratio corresponding to the target gray value; when the target gray value exceeds the threshold value, controlling the duty ratio of the driving current of the LED in the working period to be constant at a preset ratio, and controlling the magnitude of the driving current of the LED in the working period to be a current value corresponding to the target gray value. The invention can enable the LED to work under constant higher driving current no matter in high gray scale adjustment or low gray scale adjustment, avoids the unstable display problem caused by large discreteness of the main luminous wavelength when the LED works under lower driving current, and the high gray scale adjustment and the low gray scale adjustment can be switched seamlessly.
Description
Technical Field
The invention relates to the technical field of display screen driving, in particular to an AMLED driving method and device.
Background
Currently, small-pitch LED display screens based on a PM (Passive Matrix) driving method are mainstream in the industry. With the further reduction of the size of the LED light emitting device, when the size of the light emitting chip is reduced to several tens of micrometers, the micro LED era is entered, which brings challenges to the driving process of the ultra-high density LED display screen.
AM (Active Matrix) driving is a voltage-type or current-type driving method. An AM driving method using a TFT (Thin Film Transistor) substrate is a common method for liquid crystal display and OLED display. As shown in fig. 1, the AM driving is to realize the gradation adjustment by the change of the voltage magnitude or the current magnitude. The AM driving is used for a MicroLED display screen, which is an emerging practice and has a plurality of problems. One of the problems to be solved is that, because the characteristics of the LED device are different from those of the LCD and the OLED, the dominant wavelength of the LED light emitting device fluctuates in a large range at a low driving current, and the stability of the dominant wavelength cannot be ensured. FIG. 2 shows the dominant wavelengths of 3 LED light-emitting device samples at different current densities, when the current density is lower than 10mA/mm2The dominant wavelengths of the 3 samples showed a large difference.
Therefore, the conventional AM driving technique has a poor gray scale display effect at low gray scales, which seriously affects the user's use.
Disclosure of Invention
The present invention is directed to overcome at least one of the above-mentioned drawbacks (i.e., disadvantages) of the prior art, and provides an AMLED driving method and apparatus, which can enable an LED to operate at a constant high driving current regardless of whether the LED is used for high gray scale adjustment or low gray scale adjustment, thereby avoiding the unstable display problem caused by the large dispersion of the dominant light wavelength when the LED operates at a low driving current.
The technical scheme adopted by the invention is as follows:
an AMLED driving method for driving LEDs to display at a target gray scale value in a working cycle, comprising the following steps:
when the target gray value does not exceed a threshold value, controlling the driving current of the LED in a working period to be a preset current value constantly, and controlling the duty ratio of the driving current of the LED in the working period to be a ratio corresponding to the target gray value; and when the target gray value exceeds a threshold value, controlling the duty ratio of the driving current of the LED in the working period to be constant at a preset ratio, and controlling the magnitude of the driving current of the LED in the working period to be a current value corresponding to the target gray value.
When the LED needs to be displayed in higher gray scale, the LED can realize the adjustment of the high gray scale under higher driving current by controlling the magnitude of the driving current under the constant duty ratio of the driving current; when the LED needs to display with lower gray scale, the duty ratio of the driving current is controlled under the condition of constant driving current, so that the LED can still realize the adjustment of the low gray scale when working under higher driving current. The high gray scale stage adopts a current magnitude modulation mode and the low gray scale stage adopts a current duty ratio modulation mode, and the LED always works under higher driving current no matter the low gray scale stage is regulated or the high gray scale stage is regulated, so that the problem of gray scale display effect deviation caused by large dispersion of dominant wavelength when the LED works under lower driving current can be solved.
An AMLED driving device is used for driving an LED to display with a target gray value in a working period and comprises a current magnitude control circuit and a current duty ratio control circuit;
the current magnitude control circuit is used for controlling the driving current magnitude of the LED in the working period to be a preset current value constantly when the target gray value does not exceed a threshold value, and controlling the driving current magnitude of the LED in the working period to be a current value corresponding to the target gray value when the target gray value exceeds the threshold value;
the current duty ratio control circuit is used for controlling the driving current duty ratio of the LED in a working period to be a ratio corresponding to the target gray value when the target gray value does not exceed a threshold value; and when the target gray value exceeds a threshold value, controlling the duty ratio of the driving current of the LED in the working period to be constant at a preset ratio.
When the LED needs to be displayed in higher gray scale, the current magnitude control circuit controls the magnitude of the driving current under the condition that the current duty ratio control circuit controls the duty ratio of the driving current to be constant, so that the LED can realize the adjustment of high gray scale under higher driving current; when the LED needs to display with lower gray scale, the current duty ratio control circuit controls the duty ratio of the driving current under the condition that the current magnitude control circuit controls the magnitude of the driving current to be constant, so that the LED can still realize the adjustment of the low gray scale when working under higher driving current. The high gray scale stage adopts a current magnitude modulation mode and the low gray scale stage adopts a current duty ratio modulation mode, and the LED always works under higher driving current no matter the low gray scale stage is regulated or the high gray scale stage is regulated, so that the problem of gray scale display effect deviation caused by large dispersion of dominant wavelength when the LED works under lower driving current can be solved.
Compared with the prior art, the invention has the beneficial effects that: the gray scale in the high gray scale range is adjusted by controlling the size of the driving current, and the gray scale in the low gray scale range is adjusted by controlling the duty ratio of the driving current, so that the LED works on a higher constant working current no matter in low gray or high gray, the luminous dominant wavelength can be in a more stable state, and the unstable problem of the LED during low gray display is avoided.
Drawings
Fig. 1 is a schematic diagram illustrating a gray scale control by a change in voltage or current in the prior art.
Fig. 2 shows dominant wavelengths of LED light emitting device samples at different current densities.
Fig. 3 is a schematic diagram of an AMLED driving method according to an embodiment of the invention.
Fig. 4 is a schematic diagram of a gray scale signal and a clock signal in an embodiment of the invention.
Fig. 5 is a schematic diagram of a first AMLED driving device according to an embodiment of the invention.
Fig. 6 is a schematic diagram of a second AMLED driving device according to an embodiment of the invention.
Fig. 7 is a schematic diagram of a third AMLED driving device in accordance with an embodiment of the invention.
Fig. 8 is a diagram illustrating a fourth AMLED driving device according to an embodiment of the invention.
Fig. 9 is a schematic diagram of a fifth AMLED driving device according to an embodiment of the invention.
Detailed Description
The drawings are only for purposes of illustration and are not to be construed as limiting the invention. For a better understanding of the following embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
In one embodiment, an AMLED driving method for driving LEDs to display at a target gray scale value during a duty cycle is provided, the method comprising the steps of:
when the target gray value does not exceed a threshold value, controlling the driving current of the LED in a working period to be a preset current value constantly, and controlling the duty ratio of the driving current of the LED in the working period to be a ratio corresponding to the target gray value; and when the target gray value exceeds a threshold value, controlling the duty ratio of the driving current of the LED in the working period to be constant at a preset ratio, and controlling the magnitude of the driving current of the LED in the working period to be a current value corresponding to the target gray value.
When the LED needs to be displayed in higher gray scale, the LED can realize the adjustment of the high gray scale under higher driving current by controlling the magnitude of the driving current under the constant duty ratio of the driving current; when the LED needs to display with lower gray scale, the duty ratio of the driving current is controlled under the condition of constant driving current, so that the LED can still realize the adjustment of the low gray scale when working under higher driving current. The high gray scale stage adopts a current magnitude modulation mode and the low gray scale stage adopts a current duty ratio modulation mode, and the LED always works under higher driving current no matter the low gray scale stage is regulated or the high gray scale stage is regulated, so that the problem of gray scale display effect deviation caused by large dispersion of dominant wavelength when the LED works under lower driving current can be solved.
One embodiment may be to perform driving control of the LED according to fig. 3. Fig. 3 schematically illustrates the relationship between the target gray value and the magnitude and duty ratio of the LED driving current, respectively. The threshold value is recorded as GL, the preset current value is iL, and the preset ratio is H%. When the target gray value does not exceed the threshold value GL, the driving current can be controlled to be constant iL, and the duty ratio of the driving current is controlled to be increased along with the increase of the target gray value; when the target gray-scale value exceeds the threshold value GL, the duty ratio of the driving current can be controlled to be H% constantly, and the magnitude of the driving current is controlled to increase with the increase of the target gray-scale value.
When the target gray-scale value does not exceed the threshold value GL, the relationship between the target gray-scale value and the duty ratio of the driving current may be linear or non-linear; when the target gradation value exceeds the threshold value GL, the relationship between the target gradation value and the magnitude of the driving current may be linear or non-linear.
Another embodiment may be to perform the driving control of the LEDs by a look-up table. Similarly, the threshold value is recorded as GL, the preset current value is iL, and the preset ratio is H%. When the target gray value does not exceed the threshold value GL, the driving current can be controlled to be constant iL, and the duty ratio of the driving current is controlled to be the ratio corresponding to the target gray value in the table by looking up the table; when the target gray-scale value exceeds the threshold value GL, the duty ratio of the driving current can be controlled to be H% constantly, and the magnitude of the driving current is controlled to be the current value corresponding to the target gray-scale value in the table through table lookup.
As shown in fig. 4, in one embodiment, the AMLED driving method further includes:
setting a first gray signal V _ Data and a second gray signal V _ Duty according to a target gray value;
the method for controlling the driving current of the LED in the working period specifically comprises the following steps:
under the action of a first clock signal CLK1, converting a first gray scale signal V _ Data into a current magnitude control signal in a working period, and controlling the magnitude of a driving current of an LED in the working period according to the current magnitude control signal;
controlling the duty ratio of the driving current of the LED in a working period specifically comprises the following steps:
converting the second gray scale signal V _ Duty into a current Duty ratio control signal in a working period under the action of the first clock signal CLK1 and the second clock signal CLK2, and controlling the driving current Duty ratio of the LED in the working period according to the current Duty ratio control signal;
the frequency of the second clock signal CLK2 is greater than the frequency of the first clock signal CLK 1.
When the target gray value in the working period does not exceed the threshold value: under the action of a first clock signal CLK1, converting a first gray scale signal V _ Data into a current magnitude control signal in a working period, wherein the current magnitude control signal can control the driving current magnitude of the LED to be a preset current value; and simultaneously, under the action of the first clock signal CLK1 and the second clock signal CLK2, the second gray scale signal V _ Duty is converted into a current Duty ratio control signal in a working period, and the current Duty ratio control signal controls the driving current Duty ratio of the LED to be the ratio corresponding to the target gray scale value.
When the target gray-scale value in the working period exceeds the threshold value, under the action of a first clock signal CLK1, converting a first gray-scale signal V _ Data into a current magnitude control signal in the working period, wherein the current magnitude control signal can control the driving current magnitude of the LED to be a current value corresponding to the target gray-scale value; and simultaneously, under the action of the first clock signal CLK1 and the second clock signal CLK2, the second gray scale signal V _ Duty is converted into a current Duty ratio control signal in a working period, and the current Duty ratio control signal can control the driving current Duty ratio of the LED to be constant at a preset ratio.
The first gray signal V _ Data is used for controlling the driving current of the LED; the second gray signal V _ Duty is used to control a driving current Duty of the LED. The first clock signal CLK1 is used for dividing the process of controlling the LED gray scale display into different working periods, and then controlling the driving current of the LED in each working period according to the first gray scale signal V _ Data; the second clock signal CLK2 having a frequency greater than that of the first clock signal CLK1 is used to subdivide the Duty cycle into a plurality of Duty sub-cycles, and then to control the Duty ratio of each Duty sub-cycle according to the second gray scale signal V _ Duty, thereby controlling the Duty ratio of the driving current of the LED in each Duty cycle.
Through the respective control of the two gray scale signals and the mutual matching of the two clock signals, the adjustment switching of the low gray scale stage and the high gray scale stage can be seamlessly switched, and the control mode is simple.
In one embodiment, under the action of the first clock signal CLK1, the method converts the first gray scale signal V _ Data into a current magnitude control signal in a duty cycle, and controls the driving current magnitude of the LED in the duty cycle according to the current magnitude control signal, specifically including:
under the action of a first clock signal CLK1, storing first electric energy according to a first gray scale signal V _ Data in a working period;
the driving current of the LED in the working period is controlled by the stored first electric energy.
In one embodiment, under the action of the first clock signal CLK1 and the second clock signal CLK2, the second grayscale signal V _ Duty is converted into a current Duty control signal during the Duty cycle, and the driving current Duty of the LED during the Duty cycle is controlled according to the current Duty control signal, which specifically includes:
under the action of the first clock signal CLK1, storing the second electric energy according to the second gray-scale signal V _ Duty in the work period;
under the action of a second clock signal CLK2, periodically charging and discharging by using an external power supply in a working period to obtain third electric energy;
and comparing the second electric energy with the third electric energy, and controlling the duty ratio of the driving current of the LED in the working period according to the comparison result.
As shown in fig. 4, the specific implementation may be: a work cycle is divided into a data writing phase and a data display phase. In the Data writing phase, under the action of the first clock signal CLK1, in one Duty cycle, the first voltage value of the first gray signal V _ Data is latched, and the second voltage value of the second gray signal V _ Duty is latched. In the data display phase, the driving current in the LED duty cycle is controlled according to the latched first voltage value, and meanwhile, under the action of the second clock signal CLK2, in a duty sub-cycle, the second voltage value is compared with a third voltage value obtained in a periodic charging and discharging process by using an external power supply, and whether the pulse signal V _ pwm is at a high level is determined according to the comparison result, so that the driving current duty cycle in the LED duty cycle can be controlled according to the pulse signal V _ pwm to be Tdisp/Tpwm _ period, where Tpwm _ period is a duty sub-cycle, and Tdisp is the time when the pulse signal V _ pwm is at a high level in the duty sub-cycle Tpwm _ period. In another embodiment, Tdisp may also be a time when the pulse signal V _ pwm is at a low level in one duty sub-period Tpwm _ period.
As shown in fig. 5, based on the same inventive concept, in one embodiment, an AMLED driving device for driving an LED to display with a target gray scale value in a duty cycle is further provided, and includes a current magnitude control circuit 100 and a current duty control circuit 200;
the current magnitude control circuit 100 is configured to control the driving current magnitude of the LED in the working period to be a preset current value when the target gray-scale value does not exceed the threshold value, and control the driving current magnitude of the LED in the working period to be a current value corresponding to the target gray-scale value when the target gray-scale value exceeds the threshold value;
the current duty ratio control circuit 200 is used for controlling the driving current duty ratio of the LED in the working period to be a ratio corresponding to the target gray value when the target gray value does not exceed the threshold value; and when the target gray value exceeds the threshold value, controlling the duty ratio of the driving current of the LED in the working period to be constant at a preset ratio.
When the LED needs to display with higher gray scale, the current magnitude control circuit 100 controls the magnitude of the driving current under the control of the current duty control circuit 200 to make the LED realize the adjustment of high gray scale under higher driving current with constant driving current duty; when the LED needs to display with lower gray scale, the current duty ratio control circuit 200 controls the duty ratio of the driving current under the condition that the current magnitude control circuit 100 controls the driving current to be constant, so that the LED can still realize the adjustment of the low gray scale when working at higher driving current. The high gray scale stage adopts a current magnitude modulation mode and the low gray scale stage adopts a current duty ratio modulation mode, and the LED always works under higher driving current no matter the low gray scale stage is regulated or the high gray scale stage is regulated, so that the problem of gray scale display effect deviation caused by large dispersion of dominant wavelength when the LED works under lower driving current can be solved.
In a specific implementation, the positions of the current magnitude control circuit 100 and the current duty cycle control circuit 200 may be exchanged. In a specific implementation process, the LED may be connected in series between the power supply VDD1 and the current level control circuit 100, may be connected in series between the current level control circuit 100 and the current duty cycle control circuit 200, or may be connected in series between the current duty cycle control circuit 200 and a ground plane.
As shown in fig. 6, in one embodiment, the current magnitude control circuit 100 includes a first control circuit 110 and a first driving unit 120; the current duty control circuit 200 includes a second control circuit 210 and a second driving unit 220;
the first control circuit 110, configured to convert the first gray scale signal V _ Data into a current magnitude control signal in a duty cycle under the action of the first clock signal CLK1, and send the current magnitude control signal to the first driving unit 120;
the first driving unit 120 is configured to control a driving current of the LED in a duty cycle according to the received current magnitude control signal;
a second control circuit 210 for converting the second gray-scale signal V _ Duty into a current Duty control signal during a Duty cycle under the action of the first clock signal CLK1 and the second clock signal CLK2, and transmitting the current Duty control signal to the first control circuit
A second driving unit 220;
a second control circuit 210 for controlling the duty ratio of the driving current of the LED in the duty cycle according to the received current duty ratio control signal;
the first and second gray signals V _ Data and V _ Duty are respectively set according to target gray values of the LEDs, and the frequency of the second clock signal CLK2 is greater than the frequency of the first clock signal CLK 1.
When the target gray value in the working period does not exceed the threshold value: under the action of the first clock signal CLK1, the first control circuit 110 converts the first gray scale signal V _ Data into a current magnitude control signal in the duty cycle, and the first driving unit 120 controls the driving current magnitude of the LED to be a preset current value according to the current magnitude control signal; meanwhile, under the action of the first clock signal CLK1 and the second clock signal CLK2, the second control circuit 210 converts the second gray scale signal V _ Duty into a current Duty control signal in a Duty cycle, and the second driving unit 220 controls the driving current Duty of the LED to be a ratio corresponding to the target gray scale value according to the current Duty control signal.
When the target gray-scale value in the working period exceeds the threshold value, under the action of the first clock signal CLK1, the first gray-scale signal V _ Data is converted into a current magnitude control signal in the working period, and the first driving unit 120 controls the driving current magnitude of the LED to be a current value corresponding to the target gray-scale value according to the current magnitude control signal; meanwhile, under the action of the first clock signal CLK1 and the second clock signal CLK2, the second gray signal V _ Duty is converted into a current Duty control signal in a Duty cycle, and the second driving unit 220 controls the driving current Duty of the LED to be constant at a preset ratio according to the current Duty control signal.
The first gray signal V _ Data is used for controlling the driving current of the LED; the second gray signal V _ Duty is used to control a driving current Duty of the LED. The first clock signal CLK1 is used for dividing the process of controlling the LED gray scale display into different working periods, and then controlling the driving current of the LED in each working period according to the first gray scale signal V _ Data; the second clock signal CLK2 having a frequency greater than that of the first clock signal CLK1 is used to subdivide the Duty cycle into a plurality of Duty sub-cycles, and then to control the Duty ratio of each Duty sub-cycle according to the second gray scale signal V _ Duty, thereby controlling the Duty ratio of the driving current of the LED in each Duty cycle.
As shown in fig. 4, the specific implementation may be: a work cycle is divided into a data writing phase and a data display phase. In the Data writing phase, under the action of the first clock signal CLK1, the voltage value in the first gray signal V _ Data is latched by the first energy storage unit 112 and the voltage value in the first gray signal V _ Data is latched by the second energy storage unit 232 in one working cycle
The voltage value in the second gray level signal V _ Duty is latched. In the data display phase, the first driving unit 120 controls the driving current in the LED duty cycle according to the voltage value stored in the first energy storage unit 112, and meanwhile, under the action of the second clock signal CLK2, in a duty cycle, compares the voltage value stored in the second energy storage unit 232 with the voltage value stored in the third energy storage unit 223 in the periodic charging and discharging process, and determines whether the pulse signal V _ pwm is at a high level according to the comparison result, so that the second driving unit 220 can control the driving current duty cycle in the LED duty cycle to be Tdisp/Tpwm _ period according to the pulse signal V _ pwm, where Tpwm _ period is a duty cycle and Tdisp is the time when the pulse signal V _ pwm is at a high level in the duty cycle Tpwm _ period. In another embodiment, Tdisp may also be a time when the pulse signal V _ pwm is at a low level in one duty sub-period Tpwm _ period.
Through the respective control of the two gray scale signals and the mutual matching of the two clock signals, the adjustment switching of the low gray scale stage and the high gray scale stage can be seamlessly switched, and the control mode is simple.
As shown in fig. 7, in one embodiment, the first control circuit 110 includes a first switching unit 111 and a first energy storage unit 112, the first switching unit 111 is provided with a first terminal, a second terminal and a gate terminal, the first energy storage unit 112 is provided with a first terminal and a second terminal;
the gate terminal of the first switching unit 111 is connected to the first clock signal CLK1, the first terminal is connected to the first gray scale signal V _ Data, the second terminals are respectively connected to the first terminal of the first energy storage unit 112 and the first driving unit 120, and the second terminal of the first energy storage unit 112 is grounded.
The first clock signal CLK1 triggers the gate terminal of the first switch unit 111 during the duty cycle, so that the first terminal and the second terminal of the first switch unit 111 are turned on, the electric energy in the first gray signal V _ Data can be stored in the first energy storage unit 112, and the driving current of the LED during the duty cycle is controlled by the electric energy stored in the first energy storage unit 112.
In one embodiment, the second control circuit 210 includes a first input circuit 211, a second input circuit 212, and a comparison unit 213;
a first input circuit 211 for converting the second gray-scale signal V _ Duty into a first input signal by the first clock signal CLK1 and inputting the first input signal into the comparison unit 213;
a second input circuit 212 for generating a periodic second input signal under the action of a second clock signal CLK2 and inputting the second input signal to the comparison unit 213;
the comparing unit 213 is configured to compare the first input signal and the second input signal, form a current duty control signal according to the comparison result, and send the current duty control signal to the second driving unit 220.
The comparison unit 213 can compare the first input signal output by the first input circuit 211 with the second input signal output by the second input circuit 212, and determine whether the current duty control signal is at a high level according to the logic comparison result, thereby controlling the duty of the driving current in the LED duty cycle.
As shown in fig. 8, in one embodiment, the first input circuit 211 includes a second switching unit 231 and a second energy storage unit 232, the second switching unit 231 is provided with a first terminal, a second terminal and a gate terminal, and the second energy storage unit 232 is provided with a first terminal and a second terminal;
the gate terminal of the second switching unit 231 is connected to the first clock signal CLK1, the first terminal is connected to the second gray scale signal V _ Duty, the second terminals are respectively connected to the first terminal of the second energy storage unit 232 and the comparing unit 213, and the second terminal of the second energy storage unit 232 is grounded.
The first clock signal CLK1 triggers the gate terminal of the second switching unit 231 during the Duty cycle, so that the first terminal and the second terminal of the second switching unit 231 are conducted, the power in the second gray-scale signal V _ Duty can be stored in the second energy storage unit 232, and the first input signal is formed by the power stored in the second energy storage unit 232.
In one embodiment, the second input circuit 212 includes a logic unit 233, a third switching unit 234, a fourth switching unit 235 and a third energy storage unit 236, the logic unit 233 is provided with an input end and an output end, the third switching unit 234 and the fourth switching unit 235 are respectively provided with a first terminal, a second terminal and a gate terminal, and the third energy storage unit 236 is provided with a first terminal and a second terminal;
the input end of the logic unit 233 is connected to the second clock signal CLK2, and the output end is connected to the gate terminal of the third switching unit 234 and the gate terminal of the fourth switching unit 235, respectively;
a first terminal of the third switching unit 234 is connected to the power supply, a second terminal of the third switching unit 234 is connected to a first terminal of the fourth switching unit 235, a first terminal of the third energy storage unit 236 and the comparing unit 213, respectively, and a second terminal of the fourth switching unit 235 is grounded and connected to a second terminal of the third energy storage unit 236.
Under the action of the logic unit 233, the second clock signal CLK2 triggers the gate terminal of the third switching unit 234 during the first N% (0 < N% < 100%) of the duty sub-cycle, so that the first terminal and the second terminal of the third switching unit 234 are turned on, and simultaneously triggers the gate terminal of the fourth switching unit 235, so that the first terminal and the second terminal of the fourth switching unit 235 are turned off, and at this time, the power supply is charging the third energy storage unit 236; the second clock signal CLK2 triggers the gate terminal of the third switching unit 234 during the last 1-N% of the duty cycle, such that the first terminal and the second terminal of the third switching unit 234 are turned off, and simultaneously triggers the gate terminal of the fourth switching unit 235, such that the first terminal and the second terminal of the fourth switching unit 235 are turned on, and the third energy storage unit 236 is discharging. Therefore, the third energy storage unit 236 can be periodically charged and discharged under the action of the second clock signal CLK2, so that the electric energy stored in the third energy storage unit 236 changes periodically.
The comparing unit 213 may form a current duty ratio control signal by comparing the electric energy stored in the second energy storage unit 232 with the electric energy stored in the third energy storage unit 236, which changes periodically, so as to control the driving current duty ratio of the LED in the working period.
As shown in fig. 9, the specific implementation may be: the first switching unit 111 is a switching transistor T1, the first energy storage unit 112 is a capacitor Cs, the second switching unit 231 is a switching transistor T6, the third switching unit 234 is a switching transistor T4,
the fourth switching unit 235 is a switching transistor T5; the first energy storage unit 112 is a capacitor Cs, the second energy storage unit 232 is a capacitor Cd, and the third energy storage unit 236 is a capacitor Cc; the first driving unit 120 is a driving transistor T2, and the second driving unit 220 is a switching transistor T3; the comparing unit 213 is a comparator U1, and the logic unit 233 is a not gate U2. In this embodiment, the switching transistor T4 is a PMOS type transistor, and the remaining transistors are NMOS type transistors. In other embodiments, other types of transistors can be selected according to actual conditions and the specific connection mode can be adjusted according to the types of the transistors.
The gate of the switching transistor T1 is connected to the first clock signal CLK1, the source is connected to the first gray scale signal V _ Data, and the drain is connected to one end of the capacitor Cs and the gate of the driving transistor T2, respectively; the other end of the capacitor Cs is grounded.
The gate of the switching transistor T6 is connected to the first clock signal CLK1, the source is connected to the second gray-scale signal V _ Duty, and the drain is connected to one end of the capacitor Cd and the positive input end of the comparator U1, respectively; the other end of the capacitor Cd is grounded.
The input end of the not gate U2 is connected with the second clock signal CLK2, and the output end is respectively connected with the grid of the switch transistor T4 and the grid of the switch transistor T5; the source electrode of the switch transistor T4 is connected with a power supply VDD2, and the drain electrode is respectively connected with the drain electrode of the switch transistor T5, one end of the capacitor Cc and the negative input end of the comparator U1; the source of the switching transistor T5 is connected to the other end of the capacitor Cc and to ground; the output end of the comparator U1 is connected with the grid electrode of the switch transistor T3;
the anode of the LED is connected with a power supply VDD 1; the drain electrode of the switch transistor T3 is connected with the cathode electrode of the LED, and the source electrode is connected with the drain electrode of the driving transistor T2; the source of the driving transistor T2 is grounded.
As shown in fig. 4 and 9, when the first clock signal CLK1 is at a high level (i.e., in a Data writing phase in a Duty cycle), the voltage value of the first gray signal V _ Data is latched in the capacitor Cs through the switching transistor T1, and the voltage value of the second gray signal V _ Duty is latched in the capacitor Cd through the switching transistor T6. The voltage value latched in the capacitor Cs controls the magnitude of the driving current of the LED through the driving transistor T2 until the next time the first clock signal CLK1 is high level.
During the period of two previous and subsequent times when the first clock signal CLK1 is at a high level (i.e., during the data display period in which the first clock signal CLK1 is at a low level), when the second clock signal CLK2 is at a high level, the switching transistor T4 is turned on, the switching transistor T5 is turned off, the power supply VDD2 starts to charge the capacitor Cc, and when the charging starts, the voltage value of the capacitor Cc is smaller than that of the capacitor Cd, and at this time, the positive input terminal voltage value of the comparator U1 is higher than that of the negative input terminal voltage value, and the comparator U1 outputs a high level; with the increase of the charging time, the voltage value of the capacitor Cc is larger than that of the capacitor Cd, at this time, the voltage value of the positive input end of the comparator U1 is lower than that of the negative input end, and the comparator U1 outputs a low level; when the second clock signal CLK2 is at a low level, the switching transistor T4 is turned off, the switching transistor T5 is turned on, and the capacitor Cc starts to discharge, so that the comparator U1 keeps outputting a low level until the next time the second clock signal CLK2 is at a high level. Since the frequency of the second clock signal CLK2 is higher than the frequency of the first clock signal CLK1, the pulse signal V _ pwm output by the comparator U1 can control the duty ratio of the driving current of the LED through the driving transistor T3 during the period in which the first clock signal CLK1 is at the high level twice before and after (i.e., during the data display period in which the first clock signal CLK1 is at the low level within the duty cycle).
It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the specific embodiments of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention claims should be included in the protection scope of the present invention claims.
Claims (8)
1. An AMLED driving method for driving an LED to display at a target gray-scale value in a duty cycle, comprising the steps of:
when the target gray value does not exceed a threshold value, controlling the driving current of the LED in a working period to be a preset current value constantly, and controlling the duty ratio of the driving current of the LED in the working period to be a ratio corresponding to the target gray value;
when the target gray value exceeds a threshold value, controlling the duty ratio of the driving current of the LED in a working period to be constant at a preset ratio, and controlling the magnitude of the driving current of the LED in the working period to be a current value corresponding to the target gray value;
setting a first gray signal and a second gray signal according to the target gray value;
controlling the magnitude of the driving current of the LED in a working period, specifically:
under the action of a first clock signal, converting the first gray scale signal into a current magnitude control signal in a working period, and controlling the driving current magnitude of the LED in the working period according to the current magnitude control signal;
controlling the duty ratio of the driving current of the LED in a working period, specifically:
under the action of a first clock signal and a second clock signal, converting a second gray signal into a current duty ratio control signal in a working period, and controlling the duty ratio of the driving current of the LED in the working period according to the current duty ratio control signal;
the frequency of the second clock signal is greater than the frequency of the first clock signal.
2. The AMLED driving method as recited in claim 1, wherein the converting the first gray scale signal into a current level control signal during a duty cycle under the action of the first clock signal, and controlling the driving current level of the LEDs during the duty cycle according to the current level control signal, comprises:
under the action of a first clock signal, storing first electric energy according to the first gray scale signal in a working period;
and controlling the driving current of the LED in the working period by the stored first electric energy.
3. The AMLED driving method as recited in claim 1, wherein the converting, under the action of the first clock signal and the second clock signal, the second gray scale signal into a current duty cycle control signal during the duty cycle, and controlling the driving current duty cycle of the LED during the duty cycle according to the current duty cycle control signal, comprises:
under the action of a first clock signal, storing second electric energy in a working cycle according to the second gray scale signal;
under the action of a second clock signal, utilizing an external power supply to perform periodic charging and discharging in a working period to obtain third electric energy;
and comparing the second electric energy with the third electric energy, and controlling the duty ratio of the driving current of the LED in the working period according to the comparison result.
4. An AMLED driving device is used for driving an LED to display at a target gray scale value in a working period and is characterized by comprising a current magnitude control circuit and a current duty ratio control circuit;
the current magnitude control circuit is used for controlling the driving current magnitude of the LED in the working period to be a preset current value constantly when the target gray value does not exceed a threshold value, and controlling the driving current magnitude of the LED in the working period to be a current value corresponding to the target gray value when the target gray value exceeds the threshold value;
the current duty ratio control circuit is used for controlling the driving current duty ratio of the LED in a working period to be a ratio corresponding to the target gray value when the target gray value does not exceed a threshold value; when the target gray value exceeds a threshold value, controlling the duty ratio of the driving current of the LED in a working period to be constant at a preset ratio;
the current magnitude control circuit comprises a first control circuit and a first driving unit; the current duty cycle control circuit comprises a second control circuit and a second driving unit;
the first control circuit is used for converting the first gray scale signal into a current magnitude control signal in a working period under the action of a first clock signal and sending the current magnitude control signal to the first driving unit;
the first driving unit is used for controlling the driving current of the LED in a working period according to the received current control signal;
the second control circuit is used for converting a second gray signal into a current duty ratio control signal in a working period under the action of the first clock signal and the second clock signal and sending the current duty ratio control signal to the second driving unit;
the second control circuit is used for controlling the duty ratio of the driving current of the LED in a working period according to the received current duty ratio control signal;
the first gray signal and the second gray signal are respectively set according to a target gray value of the LED, and the frequency of the second clock signal is greater than that of the first clock signal.
5. The AMLED driver arrangement according to claim 4, wherein the first control circuit comprises a first switching cell and a first energy storage cell, the first switching cell having a first terminal, a second terminal and a gate terminal, the first energy storage cell having a first terminal and a second terminal;
the gate terminal of the first switch unit is connected to the first clock signal, the first terminal is connected to the first gray scale signal, the second terminal is connected to the first terminal of the first energy storage unit and the first driving unit, and the second terminal of the first energy storage unit is grounded.
6. The AMLED driving device according to claim 4, wherein the second control circuit comprises a first input circuit, a second input circuit and a comparison unit;
the first input circuit is used for converting the second gray scale signal into a first input signal under the action of a first clock signal and inputting the first input signal into the comparison unit;
the second input circuit is used for generating a periodic second input signal under the action of a second clock signal and inputting the second input signal into the comparison unit;
the comparison unit is used for comparing the first input signal with the second input signal, forming the current duty ratio control signal according to a comparison result, and sending the current duty ratio control signal to the second driving unit.
7. The AMLED driver arrangement of claim 6, wherein the first input circuit comprises a second switching cell and a second energy storage cell, the second switching cell having a first terminal, a second terminal and a gate terminal, the second energy storage cell having a first terminal and a second terminal;
the grid terminal of the second switch unit is connected with the first clock signal, the first terminal of the second switch unit is connected with the second gray scale signal, the second terminals of the second switch unit are respectively connected with the first terminal of the second energy storage unit and the comparison unit, and the second terminal of the second energy storage unit is grounded.
8. The AMLED driving apparatus according to claim 6, wherein the second input circuit comprises a logic cell, a third switching cell, a fourth switching cell and a third energy storage cell, the logic cell having an input and an output, the third switching cell and the fourth switching cell having a first terminal, a second terminal and a gate terminal, respectively, the third energy storage cell having a first terminal and a second terminal;
the input end of the logic unit is connected with the second clock signal, and the output end of the logic unit is respectively connected with the gate terminal of the third switch unit and the gate terminal of the fourth switch unit;
the first terminal of the third switching unit is connected with a power supply, the second terminal of the third switching unit is respectively connected with the first terminal of the fourth switching unit, the first terminal of the third energy storage unit and the comparison unit, and the second terminal of the fourth switching unit is grounded and connected with the second terminal of the third energy storage unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911122572.6A CN111312154B (en) | 2019-11-15 | 2019-11-15 | AMLED driving method and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911122572.6A CN111312154B (en) | 2019-11-15 | 2019-11-15 | AMLED driving method and device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111312154A CN111312154A (en) | 2020-06-19 |
| CN111312154B true CN111312154B (en) | 2022-06-17 |
Family
ID=71146661
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911122572.6A Active CN111312154B (en) | 2019-11-15 | 2019-11-15 | AMLED driving method and device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111312154B (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP4156159A4 (en) * | 2020-06-30 | 2023-08-09 | Huawei Technologies Co., Ltd. | PIXEL ATTACK CIRCUIT |
| CN112967660B (en) * | 2020-08-25 | 2022-03-01 | 重庆康佳光电技术研究院有限公司 | Display control method and device and display equipment |
| TWI742956B (en) * | 2020-12-08 | 2021-10-11 | 友達光電股份有限公司 | Pixel circuit and display panel |
| CN113948040B (en) * | 2021-11-22 | 2023-07-07 | 视涯科技股份有限公司 | Display panel |
| CN114241980A (en) * | 2021-12-17 | 2022-03-25 | 重庆惠科金渝光电科技有限公司 | Drive chip, control method and display panel |
| TWI805176B (en) * | 2022-01-07 | 2023-06-11 | 友達光電股份有限公司 | Display device and driving method thereof |
| CN114783357B (en) * | 2022-04-14 | 2023-07-25 | Tcl华星光电技术有限公司 | Pixel driving circuit and display panel |
| CN115424576B (en) * | 2022-10-31 | 2023-04-11 | 杭州视芯科技股份有限公司 | LED display system and display control method thereof |
| CN115881059B (en) * | 2022-12-09 | 2025-08-08 | 深圳创维－Rgb电子有限公司 | Display screen brightness adjustment method and electronic device |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20070126667A1 (en) * | 2005-12-01 | 2007-06-07 | Toshiba Matsushita Display Technology Co., Ltd. | El display apparatus and method for driving el display apparatus |
| JP2011048101A (en) * | 2009-08-26 | 2011-03-10 | Renesas Electronics Corp | Pixel circuit and display device |
| CN101902861B (en) * | 2010-08-10 | 2013-09-11 | 友达光电股份有限公司 | Light-emitting diode driving method and driving circuit |
| CN104392698A (en) * | 2014-12-17 | 2015-03-04 | 广州新视界光电科技有限公司 | LED display device and LED screen brightness uniformity regulating method |
| CN104599637A (en) * | 2015-02-11 | 2015-05-06 | 京东方科技集团股份有限公司 | Pixel circuit drive method and drive device |
| CN105590588B (en) * | 2015-12-21 | 2018-06-29 | 武汉华星光电技术有限公司 | Backlight adjusting method, liquid crystal display device and electronic equipment |
| US10839771B2 (en) * | 2016-12-22 | 2020-11-17 | Intel Corporation | Display driver |
| WO2018190503A1 (en) * | 2017-04-11 | 2018-10-18 | Samsung Electronics Co., Ltd. | Pixel circuit of display panel and display device |
| CN110021263B (en) * | 2018-07-05 | 2020-12-22 | 京东方科技集团股份有限公司 | Pixel circuit and driving method thereof, and display panel |
| CN109872680B (en) * | 2019-03-20 | 2020-11-24 | 京东方科技集团股份有限公司 | Pixel circuit and driving method, display panel and driving method, and display device |
| CN110446308B (en) * | 2019-09-04 | 2025-02-21 | 杭州必易微电子有限公司 | Control circuit, drive circuit, LED lamp system and control method for controlling power transistor |
-
2019
- 2019-11-15 CN CN201911122572.6A patent/CN111312154B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN111312154A (en) | 2020-06-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111312154B (en) | AMLED driving method and device | |
| US8963907B2 (en) | Pixel circuit and driving method thereof | |
| US10762848B2 (en) | Display device and driving method for the same | |
| US11270636B2 (en) | Pixel circuit and driving method | |
| CN111341252B (en) | pixel circuit | |
| CN112927651A (en) | Pixel driving circuit, active electroluminescent display and driving method | |
| CN114038415B (en) | Pixel circuit and display panel | |
| CN112164361B (en) | Pixel circuit, driving method thereof and display panel | |
| US10755657B2 (en) | Energy retrievable data driver, display, and method of driving display | |
| CN113487997A (en) | Pixel circuit, driving method thereof and display device | |
| CN114512087A (en) | Pixel circuit and display panel | |
| KR20080004181A (en) | Level shifter and its driving method | |
| CN114267281A (en) | Pixel circuit and display panel | |
| KR20200068556A (en) | Electronic Device Capable of Reducing Color Shift | |
| WO2015118601A1 (en) | Display device | |
| US11810512B2 (en) | Pixel circuit and display panel | |
| TWI711026B (en) | Driving circuit for improving low-gray-scale display effect of LED and LED display device using it | |
| US12154491B2 (en) | Pixel circuit, display panel and display device | |
| CN110706657B (en) | Pixel circuit and display device | |
| CN117456884A (en) | Pixel driving circuit, driving method thereof and display panel | |
| CN115223494A (en) | Drive circuit and display panel | |
| US12315436B2 (en) | Display panel and pixel circuit thereof | |
| CN114627804B (en) | Pixel circuit and display panel | |
| US12260804B2 (en) | Pixel circuit and display panel | |
| US20250111820A1 (en) | Pixel driving 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 |