The present disclosure relates to the field of integrated circuits. More specifically, the present disclosure relates to a display device including a light emitting unit array and a driver for driving the light emitting unit array of the display device.
In recent years, with the continuous development of display technology and the increasing requirements of consumers for the display resolution of electronic devices such as mobile phones and televisions, designers are required to integrate high-density light emitting unit arrays (e.g., LED) in a limited space. However, in high resolution applications, there are several problems in driving such light emitting unit arrays. For example, insufficient slew rate of the driver results in the inability to output a complete pulse, the coupling effect between channels results in the incorrect lighting behavior, or the slew rate of the driver is inconsistent under different coupling conditions, and so on. Therefore, it is desired in the art to provide an improved driver and a display device using the driver.
In view of above, the present disclosure provides a display device and a driver thereof, which can at least improve the output slew rate of the driver, and can dynamically adjust the improvement of the slew rate.
According to an aspect of the present disclosure, there is provided a driver for driving a light emitting unit array of a display device, the driver including a plurality of driving units, each of the plurality of driving units includes: a driving circuit configured to provide a driving current to a corresponding column of light emitting units in the light emitting unit array according to a pulse width modulation signal, during a turn on period of a channel switch; a regulating circuit configured to be connected in parallel with the driving circuit and be turned-on according to the pulse width modulation signal, to form a path with the corresponding column of the light emitting units, such that a current associated with the light emitting units flows through the path.
Further, according to an embodiment of the present disclosure, the regulating circuit includes a charge path circuit, and the charge path circuit is configured to be turned-on during the turn on period of the channel switch to form a charge path, and provide a charging current to the corresponding column of the light emitting units through the charge path.
Further, according to another embodiment of the present disclosure, each of the driving units further includes a mixed-signal controller coupled to the charge path circuit, and the mixed-signal controller is configured to control the turn-on of the charge path circuit according to an edge of the pulse width modulation signal; wherein the mixed-signal controller outputs a first control signal to the charge path circuit when a rising edge of the pulse width modulation signal is detected, to turn-on a first switching element of the charge path circuit so that the charge path circuit is turned-on.
Further, according to yet another embodiment of the present disclosure, the mixed-signal controller is further configured to receive a first instruction indicating a number of light emitting units to be driven, and adjust an intensity of turn-on of the charge path circuit according to the first instruction.
Further, according to yet another embodiment of the present disclosure, adjusting the intensity of turn-on of the charge path circuit includes: making a turn-on duration of the charge path circuit to be inversely proportional to the number of light emitting units to be driven indicated by the first instruction; or making a value of the charging current output by the charge path circuit to be inversely proportional to the number of light emitting units to be driven indicated by the first instruction; or making both the turn-on duration of the charge path circuit and the value of the charging current output by the charge path circuit to be inversely proportional to the number of light emitting units to be driven indicated by the first instruction.
Further, according to yet another embodiment of the present disclosure, the mixed-signal controller is further configured to receive a second instruction indicating that the display device enters a power saving mode, and set the intensity of turn-on of the charge path circuit to a fixed value according to the second instruction.
Further, according to yet another embodiment of the present disclosure, the mixed-signal controller is further configured to receive display data; generate the pulse width modulation signal and provide it to the driving circuit, wherein the pulse width of the generated pulse width modulation signal is based on the display data.
Further, according to yet another embodiment of the present disclosure, the regulating circuit includes a discharge path circuit, and the discharge path circuit is configured to be turned-on after the channel switch is turned off, to form a discharge path, so that the residual charges of the corresponding column of the light emitting units are discharged through the discharge path.
Further, according to yet another embodiment of the present disclosure, each of the driving units further includes a mixed-signal controller coupled to the discharge path circuit, and the mixed-signal controller is configured to control the turn-on of the discharge path circuit according to an edge of the pulse width modulation signal; wherein the mixed-signal controller output a second control signal to the discharge path circuit when a falling edge of the pulse width modulation signal is detected, to turn-on a second switching element of the discharge path circuit, so that the discharge path circuit is turned-on.
Further, according to yet another embodiment of the present disclosure, the mixed-signal controller is further configured to receive a third instruction indicating a number of light emitting units to be turned off, and adjust an intensity of turn-on of the discharge path circuit according to the third instruction.
Further, according to yet another embodiment of the present disclosure, adjusting the intensity of turn-on of the discharge path circuit includes: making a turn-on duration of the discharge path circuit to be inversely proportional to the number of light emitting units to be turned off indicated by the third instruction; or making a value of the discharged current flowing through the discharge path circuit to be inversely proportional to the number of light emitting units to be turned off indicated by the third instruction; or making both the turn-on duration of the discharge path circuit and the value of the discharged current flowing through the discharge path circuit to be inversely proportional to the number of light emitting units to be turned off indicated by the third instruction.
According to another aspect of the present disclosure, there is provided a driver for driving a light emitting unit array of a display device, the driver including a plurality of driving units, each of the plurality of driving units includes: a driving circuit configured to provide a driving current to a corresponding column of light emitting units in the light emitting unit array according to a pulse width modulation signal, during a turn on period of a channel switch; a charge path circuit configured to be connected in parallel with the driving circuit, and to be turned on during the turn on period of the channel switch to form a charge path, and to provide a charging current to the corresponding column of the light emitting units through the charge path; and a discharge path circuit configured to be connected in parallel with the driving circuit, and to be turned-on after the channel switch is turned off, to form a discharge path, so that the residual charges of the corresponding column of the light emitting units are discharged through the discharge path.
Further, according to an embodiment of the present disclosure, each of the driving units further includes a mixed-signal controller coupled to the charge path circuit and the discharge path circuit, and the mixed-signal controller is configured to control the turn-on of the charge path circuit and the discharge path circuit according to an edge of the pulse width modulation signal; wherein the mixed-signal controller output a first control signal to the charge path circuit when a rising edge of the pulse width modulation signal is detected, to turn-on a first switching element of the charge path circuit so that the charge path circuit is turned-on; and output a second control signal to the discharge path circuit when a falling edge of the pulse width modulation signal is detected, to turn-on a second switching element of the discharge path circuit so that the discharge path circuit is turned-on.
According to another aspect of the present disclosure, there is provided a display device, including: a light emitting array consisting of a plurality of light emitting units; a driver, each of the plurality of driving units in the driver is coupled to each column of the plurality of light emitting units to drive a corresponding column of the light emitting units; a scanning module coupled to each row of the plurality of light emitting units to provide a scanning signal to a corresponding row of the light emitting units.
Further, according to an embodiment of the present disclosure, the type of the display device is a mini-LED or a micro-LED.
According to the above mentioned display device and the driver thereof of the present disclosure, the response of the light emitting elements to the output of the driver or driving unit can be dynamically improved according to the load and coupling condition of the light emitting elements to be driven.
These and other objectives of the present disclosure will become obvious to those of ordinary skill in the art after reading the following detailed description of optional embodiments.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the disclosure as claimed.
Through detailed description of the embodiments of the present disclosure in conjunction with the following drawings, the above and other objects, features, and advantages of the present disclosure will become clearer. It should be understood that these drawings are used to provide a further understanding of the embodiments of the present disclosure, and constitute a part of present specification, and are used to explain the present disclosure together with the embodiments of the present disclosure, and do not constitute a limitation of the present disclosure. In addition, in the drawings, the same reference numerals generally represent the same components or steps.
400, 500, 600: Driving Unit
401, 501, 601: Driving Circuit
402, 502: Regulating Circuit
5021, 602: Charge Path Circuit
5022, 603: Discharge Path Circuit
604: Mixed-signal Controller
605: Controller
606: Interface
607: Memory
Examples are provided below to describe the present disclosure in detail, but the present disclosure is not limited to the provided embodiments, and the provided embodiments can be combined as appropriate. It should be understood that the embodiments described herein are only a part of the embodiments of the present disclosure, rather than all the embodiments of the present disclosure. These embodiments are merely illustrative and exemplary, and therefore should not be construed as limiting the scope of the present disclosure. In addition, in order to make the description clearer and concise, detailed descriptions of well-known functions and configurations in the art will be omitted, and repeated explanations of steps and elements will also be omitted.
First, refer to
Further, according to an embodiment of the present disclosure, the LED driver as discussed herein can also be applied to a mini-LED or a micro-LED applications. Such LED applications are aimed at arraying and miniaturizing LEDs, for example, for the micro-LEDs, the size of a single LED unit is usually on the order of 50 microns or less, and it can be realized that each light emitting unit can be individually addressed and driven to emit light just like OLED. Since such LED applications have a smaller LED size, high resolutions such as 4K or even 8K can be more easily implemented in the screens of electronic devices.
With further reference to
In the LED driving applications, for lower resolution applications, since the quantity of LED rows to be driven is small, the load is small, and the shortest pulse width of the corresponding PWM is long. Therefore, as shown in the waveform diagram (a) in
In addition, due to the presence of capacitive elements in the LED array, there will be coupling between adjacent columns when the channel switch is turned-on. For example, as shown by the arrow in
With further reference to
At least to solve the above mentioned problem that the LEDs cannot be lit, according to an embodiment of the present disclosure, a driver is provided to solve the above mentioned technical problem. In this embodiment, beneficial improvements will be made to the driving units in the driver, and the driving units in this embodiment will be described in detail below with reference to
In order to improve the slew rate problem of the driving unit as described above, in this embodiment, the regulating circuit 402 will serve as a charge path circuit to provide a charge path to the LEDs of the corresponding column.
Specifically, taking the C[m] column in the LED array shown in
On the other hand, as shown in
In addition, in order to at least solve the above mentioned problem of erroneously lighting of the LEDs, according to an embodiment of the present disclosure, a driver is provided to solve the above mentioned technical problem. The driving unit 500 in this embodiment will be described in detail below with reference to
Specifically, still taking the LED array shown in
The above embodiments respectively describe that the driving unit according to the embodiment of the present disclosure includes the driving circuit and the adjusting circuit, and as described above, the adjusting circuit can be used as a charge path circuit or a discharge path circuit to do improvements to the driver accordingly. Further, according to an embodiment of the present disclosure, the adjusting circuit included in the driving unit may only serve as one of the charge path circuit or the discharge path circuit, or may also integrate the function of the charge path circuit and the discharge path circuit both. Alternatively, the charge path circuit and the discharge path circuit may also be connected in parallel with the driving circuit as a separate element respectively, and the driving unit may include one or both of the charge path circuit and the discharge path circuit.
In addition, according to the third embodiment of the present disclosure, the driver further includes a mixed-signal controller, which is coupled to the regulating circuit described above in conjunction with
Hereinafter, an optional embodiment according to the present disclosure will be described with reference to
As shown in
Optionally, the mixed-signal controller 604 is configured to output a first control signal to the charge path circuit 602, when a rising edge of the pulse width modulation signal is detected, to turn-on a first switching element of the charge path circuit so that the charge path circuit is turned-on. In this way, the turn-on timings of the charge path circuit and the channel switch can be basically synchronized, thereby rapidly raising the load potential, making up for the output delay in the initial driving stage, and achieving better response performance at high resolution. On the other hand, when the falling edge of the pulse width modulation signal is detected, the mixed-signal controller 604 is configured to output a second control signal to the discharge path circuit 603 to turn-on a second switching element of the discharge path circuit, so that the discharge path circuit is turned-on. In this way, the discharge path circuit can be turned-on immediately after the channel switch is turned off, so that the residual charges of the corresponding channel can be discharged in time, and thus avoiding erroneously lighting caused by the LED coupling with other channels.
According to various embodiments of the present disclosure, the first switching element and the second switching element in the charge path circuit and discharge path circuit may be implemented by one of the following elements: metal oxide semiconductor field effect transistor (MOSFET), diode, source follower and operational amplifier.
It should be understood that the foregoing embodiment is only an optional embodiment of the present disclosure, and the charge path circuit can also be turned-on within a period of time after the corresponding channel switch is turned-on, as long as it is turned-on during the turn-on period of the corresponding channel switch, the corresponding technical problem can be solved. It can also be understood that the discharge path circuit can also be turned-on within a period of time after the corresponding channel switch is turned off.
In addition, as described above, coupling between different channels will affect the slew rate of the driving unit. Besides that, the degree of coupling between the channels will be different depending on the number of channels to be turned-on at the same time. Hereinafter, this difference of the driving unit under different coupling conditions will be described in conjunction with
As shown in
In view of the above, according to an embodiment of the present disclosure, the mixed-signal controller is further configured to receive a first instruction indicating a number of light emitting units to be driven and a third instruction indicating a number of light emitting units to be turned off from the controller; and adjust the intensity of turn-on of the charge path circuit according to the first instruction, and adjust the intensity of turn-on of the discharge path circuit according to the third instruction.
Specifically, as shown in
According to an embodiment of the present disclosure, the instruction may be a first instruction indicating the number of light emitting units to be driven. Therefore, after the mixed-signal controller receives the first instruction, it can adjust the intensity of turn-on of the charge path depending on the number of light emitting units to be driven. For example, as shown in the waveform diagram (a) in
Optionally, according to an embodiment of the present disclosure, adjusting the intensity of turn-on of the charge path circuit includes: making the turn-on duration of the charge path circuit to be inversely proportional to the number of light emitting units to be driven indicated by the first instruction; alternatively, according to one embodiment of the present disclosure, adjusting the intensity of turn-on of the charge path circuit includes: making a value of the charging current output by the charge path circuit to be inversely proportional to the number of light emitting units to be driven indicated by the first instruction; alternatively, according to one embodiment of the present disclosure, adjusting the intensity of turn-on of the charge path circuit includes: making both of the turn-on duration of the charge path circuit and the value of the charging current output by the charge path circuit to be inversely proportional to the number of light emitting units to be driven indicated by the first instruction.
Also, the mixed-signal controller may receive a third instruction indicating a number of light emitting units to be turned-off from the controller. Furthermore, after the mixed-signal controller receives the third instruction indicating the number of light emitting units to be turned-off, it further adjusts the intensity of turn-on of the discharge path circuit according to the third instruction.
For example, as shown in the waveform diagram (a) in
Optionally, according to an embodiment of the present disclosure, adjusting the intensity of turn-on of the discharge path circuit includes: making the turn-on duration of the discharge path circuit to be inversely proportional to the number of light emitting units to be turned-off indicated by the third instruction; alternatively, according to one embodiment of the present disclosure, adjusting the intensity of turn-on of the discharge path circuit includes: making a value of the discharging current output by the discharge path circuit to be inversely proportional to the number of light emitting units to be turned-off indicated by the third instruction; alternatively, according to one embodiment of the present disclosure, adjusting the intensity of turn-on of the discharge path circuit includes: making both of the turn-on duration of the discharge path circuit and the value of the discharging current flowing through the discharge path circuit to be inversely proportional to the number of light emitting units to be turned-off indicated by the third instruction.
By use of above methods, the charge path circuit and the discharge path circuit are able to dynamically adjust the intensity of the charging current/discharging circuit according to the number of light emitting units to be driven/turned off, so that the slew rate of the driving unit has better consistency.
Further, according to another embodiment of the present disclosure, the mixed-signal controller is further configured to receive, e.g., from the controller, a second instruction indicating the display device enters a specific mode, and adjusting the intensity of turn-on of the charge/discharge path circuit to a fixed value according to the second instruction. Specifically, when the display device enters the specific mode (such as power saving mode), the controller directly sends a instruction for fixing to the mixed-signal controller, so that the mixed-signal controller does not need to determine the intensity of turn-on of the charge/discharge path circuit according to the number of light emitting units to be driven/turned off, but adjusts the intensity of turn-on of the regulating circuit (charge path circuit/discharge path circuit) to a fixed value. In addition, according to the display device enters into different modes, the mixed-signal controller may receive different instructions to adjust the intensity of turn-on of the regulating circuit to a corresponding value.
Further, the mixed-signal controller can also receive other instructions from the controller. For example, according to another embodiment of the present disclosure, the mixed-signal controller is further configured to receive, e.g., from the controller, display data, and generate the pulse width modulation signal and provide it to the driving circuit, wherein the pulse width of the generated pulse width modulation signal is determined based on the display data, namely, by adjusting the duty cycle of the PWM in one cycle, the driving circuit is able to drive the relevant light emitting units accordingly for different display data, so that the display device can present the display data correctly.
In addition, in various embodiments of the present disclosure, the mixed-signal controller may be coupled with an regulating unit that only serves as a charge path circuit, and configured to control the turn-on of the charge path circuit according to the edge of the pulse width modulation signal, or the mixed-signal controller may be coupled with an regulating unit that only serves as a discharge path circuit, and configured to control the turn-on of the discharge path circuit according to the edge of the pulse width modulation signal, or as described above, the mixed-signal controller can be coupled with both the charge path circuit and the discharge path circuit and configured to control the turn-on of the charge path circuit and discharge path circuit according to the edge of the pulse width modulation signal.
In addition, according to different design requirements, the controllers, the mixed-signal controllers and other modules described in the above mentioned embodiments of the present disclosure can be implemented in hardware, firmware, software or programs or a combination thereof.
In terms of hardware, the controllers, the mixed-signal controllers and other modules in the above embodiments can be implemented in logic circuits on integrated circuits. The related functions of the modules in the embodiments of the present disclosure may be implemented as hardware using hardware description languages (such as Verilog HDL or VHDL) or other suitable programming languages. For example, the related functions of the controller, the mixed-signal controller and other modules in the above mentioned embodiments can be implemented in one or more controllers, microcontrollers, microprocessors, and application-specific integrated circuits (ASIC), digital signal processor (DSP), Field Programmable Gate Array (FPGA) and/or various logic blocks, modules and circuits in other processing units.
In terms of software form and/or firmware, the related functions of the controller, mixed-signal controller and other modules in the above embodiments can be implemented as programming codes. For example, general programming languages (such as C, C++, or assembly language) or other suitable programming languages are used to implement the aforementioned modules of the embodiments of the present disclosure. The programming codes may be recorded/stored in a recording medium, which includes, for example, a read only memory (ROM), a storage device, and/or a random access memory (RAM). A computer, a central processing unit (CPU), a controller, a microcontroller, or a microprocessor can read and execute the programming codes from the recording medium, thereby achieving related functions. As the recording medium, a “non-transitory computer readable medium” can be used, for example, tape, disk, card, semiconductor memory, and programmable logic circuit and the like can be used. Moreover, the program may be provided to the computer (or CPU) via any transmission media (communication network, broadcast wave, etc.). The communication network includes, for example, the Internet, wired communication, wireless communication, or other communication media.
To sum up, in the embodiment of the present disclosure, the problem of slow slew rate of the existing driver and erroneously lighting of the light emitting units can be solved by providing the above mentioned regulating circuit in the driving unit, and the intensity of turn-on of the regulating circuit is dynamically adjusted according to the number of light emitting units to be driven, so that the driving unit has a relatively consistent slew rate, and thereby achieving a good driving performance in high resolution applications.
Although the present disclosure has been disclosed in the above embodiments, it is not intended to limit the present disclosure. Any person skilled in the art can make some changes and modifications without departing from the spirit and scope of the present disclosure. The protection scope of the present disclosure shall be subject to the scope defined by the claims.
Number | Date | Country | |
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63017179 | Apr 2020 | US |