CN212624748U - LED driving chip, backlight unit, display panel and display device - Google Patents
LED driving chip, backlight unit, display panel and display device Download PDFInfo
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- CN212624748U CN212624748U CN202020552317.7U CN202020552317U CN212624748U CN 212624748 U CN212624748 U CN 212624748U CN 202020552317 U CN202020552317 U CN 202020552317U CN 212624748 U CN212624748 U CN 212624748U
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Abstract
The utility model discloses a LED driver chip, backlight unit, display panel and display device, wherein, LED driver chip is connected with a LED for control LED, include: the logic control module is used for receiving a first analog data signal shared by a row or a column of the position of the LED and converting the first analog data signal into a second analog data signal for individually controlling the LED; the logic control module comprises: the gray information coding submodule is used for coding the first analog data signal to generate a digital gray scale signal; the gray scale voltage conversion submodule is connected with the gray scale information coding submodule and is used for generating a digital output signal according to the digital gray scale signal; and the output voltage generation submodule is connected with the gray scale voltage conversion submodule and is used for generating a second analog data signal according to the digital output signal. The LED driving chip controls the LEDs independently, so that various different AM backlight driving modes are realized, and the control of the LEDs is more accurate and flexible.
Description
Technical Field
The utility model relates to a show technical field, concretely relates to LED driver chip, backlight unit, display panel and display device.
Background
Currently, the backlight of the display device can be roughly divided into two types, one type is a Passive Matrix (PM) backlight, and the other type is an Active Matrix (AM) backlight.
The PM backlight mode is relatively low in cost and easy to realize technically. However, as the display resolution is improved, the scanning time per line per unit time is shortened, and especially when the display device is applied to a large-size display device, the PM backlight mode is difficult to realize. In order to solve the above problems, the display device may be divided into several regions to be driven, and the driving structure of this method is complicated, and there is a difference in luminance between the divided regions. The AM backlight system can achieve better brightness uniformity and contrast ratio and higher resolution, and thus, the AM backlight system has become popular.
SUMMERY OF THE UTILITY MODEL
Based on this, the embodiment of the utility model provides a novel active matrix is shaded drive control's LED driver chip, backlight unit, display panel and display device.
According to a first aspect, an embodiment of the present invention provides an LED driver chip, the LED driver chip is connected to an LED for controlling the LED, the LED driver chip includes: the logic control module is used for receiving a first analog data signal shared by one row or one column of the LED and converting the first analog data signal into a second analog data signal for individually controlling the LED; the logic control module comprises: the gray information coding submodule is used for coding the first analog data signal to generate a digital gray scale signal; the gray scale voltage conversion submodule is connected with the gray scale information coding submodule and is used for generating a digital output signal according to the digital gray scale signal; and the output voltage generation submodule is connected with the gray voltage conversion submodule and used for generating a second analog data signal according to the digital output signal.
Optionally, the gray scale information encoding sub-module includes: the duty ratio detection unit is used for detecting duty ratio information of the first analog data signal and coding the duty ratio information to generate a first digital output type of the digital gray scale signal; the frequency detection unit is used for detecting the frequency information of the first analog data signal and generating a second digital output type of the digital gray-scale signal by encoding according to the frequency information; and the voltage detection unit is used for detecting the voltage information of the first analog data signal and generating a third digital output type of the digital gray-scale signal by encoding according to the voltage information.
Optionally, the gray scale information encoding sub-module further includes: and the input signal selection unit is connected with the duty ratio detection unit, the frequency detection unit and the voltage detection unit and is used for determining the digital output type of the digital gray-scale signal according to the received input control signal.
Optionally, the gray scale voltage conversion sub-module is further configured to determine a conversion relationship between the digital gray scale signal and the digital output signal according to the received conversion relationship selection signal.
Optionally, the output voltage generation submodule includes: the pulse width modulation unit is connected with the gray voltage conversion submodule and used for generating a first analog output type of a second analog data signal according to the digital output signal; and the pulse amplitude modulation unit is connected with the gray voltage conversion submodule and is used for generating a second analog output type of a second analog data signal according to the digital output signal.
Optionally, the output voltage generation sub-module further includes: and the output signal selection unit is connected with the pulse width modulation unit and the pulse amplitude modulation unit and is used for determining the analog output type of the second analog data signal according to the received output control signal.
Optionally, the LED driving chip further includes: and the first switch module is connected with the scanning signal and the logic control module and used for generating an LED control signal according to the scanning signal and the second analog data signal.
Optionally, the LED driving chip further includes: and the second switch module is connected with the first switch module and the LED and used for controlling the on and off of the LED according to the LED control signal.
Optionally, the LED driving chip further includes: and the charge storage module is connected with the first switch module and is used for storing the LED control signal.
According to a second aspect, embodiments of the present invention provide a backlight unit, including: a back plate; the light source is arranged on the back plate and comprises a plurality of LEDs which are arranged in an array; the utility model discloses in any one of the first aspect a plurality of LED driver chip set up in on the backplate, with a plurality of the LED one-to-one.
According to a third aspect, embodiments of the present invention provide a display panel, including a backlight unit according to the second aspect of the present invention.
According to a fourth aspect, an embodiment of the present invention provides a display device, including a display panel according to the third aspect of the present invention.
The utility model discloses technical scheme has following advantage:
the utility model provides a LED driver chip, LED driver chip is connected with a LED, is used for control LED, LED driver chip includes: the logic control module is used for receiving a first analog data signal shared by one row or one column of the LED and converting the first analog data signal into a second analog data signal for individually controlling the LED; the logic control module comprises: the gray information coding submodule is used for coding the first analog data signal to generate a digital gray scale signal; the gray scale voltage conversion submodule is connected with the gray scale information coding submodule and is used for generating a digital output signal according to the digital gray scale signal; and the output voltage generation submodule is connected with the gray voltage conversion submodule and used for generating a second analog data signal according to the digital output signal. According to the LED driving chip, the logic control module is used for receiving the first analog data signal and converting the first analog data signal into the second analog data signal, the LED is controlled independently, various different AM backlight driving modes are realized, and the LED is controlled more accurately and flexibly.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the technical solutions in the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic diagram of one specific example of a prior art AM driven LED;
fig. 2 is a schematic diagram of a specific example of an LED driving chip according to an embodiment of the present invention;
fig. 3 is a schematic diagram of another specific example of an LED driving chip according to an embodiment of the present invention;
fig. 4 is a schematic diagram of another specific example of an LED driving chip according to an embodiment of the present invention;
fig. 5 is a schematic diagram of another specific example of an LED driving chip according to an embodiment of the present invention;
fig. 6 is a schematic diagram of another specific example of an LED driving chip according to an embodiment of the present invention;
fig. 7 is a schematic diagram of another specific example of an LED driving chip according to an embodiment of the present invention;
fig. 8 is a schematic diagram of another specific example of an LED driving chip according to an embodiment of the present invention;
fig. 9 is a schematic diagram of another specific example of an LED driving chip according to an embodiment of the present invention;
fig. 10 is a schematic diagram of another specific example of an LED driving chip according to an embodiment of the present invention;
fig. 11 is a schematic diagram of a specific example of the working process of the LED driving chip according to the embodiment of the present invention;
fig. 12 is a schematic diagram of another specific example of the operation process of the LED driving chip according to the embodiment of the present invention;
fig. 13 is a schematic diagram of another specific example of the operation process of the LED driving chip according to the embodiment of the present invention;
fig. 14 is a schematic diagram of another specific example of the operation process of the LED driving chip according to the embodiment of the present invention;
fig. 15 is a schematic diagram of a specific example of a backlight unit according to an embodiment of the present invention;
fig. 16 is a schematic diagram of a specific example of the duty ratio detection unit according to the embodiment of the present invention;
fig. 17 is a schematic diagram of a specific example of a frequency detection unit according to an embodiment of the present invention;
fig. 18 is a diagram illustrating a specific example of a conversion relationship between a digital gray-scale signal and a digital output signal according to an embodiment of the present invention;
fig. 19 is a schematic diagram of a specific example of a pulse width modulation unit according to an embodiment of the present invention;
fig. 20 is a diagram illustrating a specific example of the PWM unit generating the PWM signal according to an embodiment of the present invention;
fig. 21 is a schematic diagram of a specific example of a pulse amplitude modulation unit according to an embodiment of the present invention;
fig. 22 is a schematic diagram of a specific example of a pulse amplitude modulation unit generating a PAM signal according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Furthermore, the technical features mentioned in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.
At present, the AM driving of the LED can be realized by a commonly used AM backlight mode through 2T1C, as shown in fig. 1, a control end of a first switch tube M1 is connected to a SCAN signal SCAN, a first end of a first switch tube M1 is connected to a DATA signal DATA, a second end of the first switch tube M1 is connected to a storage capacitor C1, a second end of the first switch tube M1 is further connected to a control end of a second switch tube M2, the second switch tube M2 is connected in series to a Light Emitting Diode (abbreviated as LED) D1, and the Light Emitting Diode D1 is turned on and off by controlling a second switch tube M2. Utility model people find, only control emitting diode through 2T1C, then emitting diode's control type is unanimous with data signal's type, that is, if data signal is the PWM signal, then emitting diode's control mode is PWM control, if data signal is the PAM signal, then emitting diode's control mode is PAM control. Due to the fact that PAM and PWM driving characteristics are different, under the condition that driving time is short, low gray scale can not be distinguished through PWM control, and therefore low gray scale expression capacity is not enough, and under the condition, PAM driving effect is better; under the condition of longer driving time, the PWM driving has better control capability than the PAM driving; therefore, in practical applications, the control of the led by only 2T1C results in poor control effect. Therefore, the embodiment of the utility model provides a novel active matrix is shaded drive control's LED driver chip, backlight unit, display panel and display device to the AM drive mode in a poor light that provides multiple difference has improved the accuracy and the flexibility of LED control.
The embodiment of the utility model provides a LED driver chip, as shown in FIG. 2, LED driver chip is connected with a LED for control this LED, LED driver chip include logic control module 1, be used for receiving the first analog data signal of the one line or a row sharing on the LED position and carry out the second analog data signal of independent control with first analog data signal conversion to LED. Wherein, logic control module 1 includes:
a Gray level information encoding sub-module (Gray level information encoding) 11, configured to encode the first analog data signal to generate a digital Gray level signal;
a Gray level to voltage conversion submodule (Gray level to voltage conversion)12, connected to the Gray information encoding submodule 11, for generating a digital output signal according to the digital Gray scale signal;
an Output voltage generation submodule (Output voltage generation)13, connected to the gray scale voltage conversion submodule 12, configured to generate a second analog data signal according to the digital Output signal.
In one embodiment, if the scan signal of the LED is row driving and the data signal is column driving, the logic control module receives a data signal shared by a column of LEDs, where the data signal is a first analog data signal, that is, the first analog data signal is a data signal shared by a column of LEDs; of course, in other embodiments, if the scan signal of the LED is column-driven and the data signal is row-driven, the first analog data signal is a data signal common to a row of LEDs. The second analog data signal is a data signal for individually controlling LEDs connected to the LED driving chip.
In one embodiment, the first analog data signal may be a PWM signal or an analog voltage signal; the present embodiment is only illustrative, and not limited thereto. The second analog data signal may be a PWM signal or a PAM signal; the present embodiment is only illustrative, and not limited thereto.
According to the LED driving chip, the logic control module is used for receiving the first analog data signal and converting the first analog data signal into the second analog data signal, so that various different AM backlight driving modes are realized, and the control of the LED is more accurate and flexible.
In one embodiment, as shown in fig. 3, the gray scale information encoding sub-module 11 includes: a duty ratio detection unit 111, configured to detect duty ratio information of the first analog data signal, and encode the duty ratio information to generate a first digital output type of the digital grayscale signal; a frequency detection unit 112, configured to detect frequency information of the first analog data signal, and encode the frequency information to generate a second digital output type of the digital grayscale signal; and a voltage detection unit 113 for detecting voltage information of the first analog data signal and generating a third digital output type of the digital gray-scale signal by encoding according to the voltage information.
Specifically, the duty ratio detecting unit 111 may be composed of a first Counter1 and a second Counter2, where the first Counter1 is used for counting the number of pulses N1 of the Detection clock signal (Detection clock) in a high level time period in one cycle, and the second Counter2 is used for counting the number of pulses N2 of the Detection clock signal (Detection clock) in a low level time period in one cycle, so that the duty ratio of the input PWM signal in the cycle is N1/(N1+ N2). Of course, in other embodiments, the second Counter2 may count the number of pulses of the detection clock signal N3 in one period, and the duty ratio is N1/N3. Note that, in order to reduce the amount of calculation, the counter is cleared at the end of one cycle.
As shown in fig. 16, when the input PWM signal is duty-detected by the detection clock signal, the number of pulses of the detection clock signal in the high level period in the first cycle is 6, and the number of pulses of the detection clock signal in the low level period is 4, the duty ratio duty of the input PWM signal in the first cycle is 6/(6+4) ═ 60%; if the number of pulses of the detection clock signal in the high level period in the second cycle is 8 and the number of pulses of the detection clock signal in the low level period is 2, the duty ratio duty of the input PWM signal in the second cycle is 8/(8+2) ═ 80%.
Specifically, the frequency detecting unit 112 may be composed of a third Counter3, where the third Counter is configured to count the number of pulses of the input PWM signal, so as to obtain the number N4 of pulses of the input PWM signal in one period, and then the frequency of the input PWM signal is 1/N4.
As shown in fig. 17, if the number of pulses of the input PWM signal in the first period is 11, the frequency of the input PWM signal in the first period is 1/11; if the number of pulses of the input PWM signal in the second period is 4, the frequency of the input PWM signal in the second period is 1/4.
Specifically, the voltage detection unit 113 may be an Analog-to-Digital Converter (ADC), such as a successive approximation ADC, an integral ADC, a sigma-delta ADC, or a pipelined ADC, which is only schematically illustrated in the embodiment, but not limited thereto, and may be reasonably configured as required in practical applications.
The duty ratio detection unit 111, the frequency detection unit 112 and the voltage detection unit 113 may automatically detect a waveform of the input first analog data signal, different input waveforms have different characteristics, and the detection unit is determined according to the input waveform, thereby obtaining a digital output type of the digital gray scale signal. For example, if the input waveform of the first analog data signal is changed according to the voltage duty ratio (different duty ratios correspond to different gray scales), the duty ratio detection unit 111 detects the duty ratio; if the input waveform of the first analog data signal is changed according to the voltage frequency (different frequencies correspond to different gray scales), the frequency detection unit 112 detects the frequency of the input waveform; the input waveform of the first analog data signal is varied according to the voltage level (different voltage levels correspond to different gray scales), and is subjected to voltage detection by the voltage detection unit 113.
According to the LED driving chip, the duty ratio detection unit 111, the frequency detection unit 112 and the voltage detection unit 113 are used for automatically detecting the waveform of the input first analog data signal, so that the detection is more accurate, and the LED control is more accurate.
In an embodiment, as shown in fig. 4, the gray scale information encoding sub-module 11 further includes: and an Input signal selection unit 114, connected to the duty ratio detection unit 111, the frequency detection unit 112, and the voltage detection unit 113, for determining a digital output type of the digital gray scale signal according to the received Input control signal Input _ select.
Specifically, the corresponding relationship between the Input control signal Input _ select and the digital output type of the digital gray-scale signal may be preset, and then the digital output type of the digital gray-scale signal may be determined according to the preset corresponding relationship. For example, when the Input control signal Input _ select is 0, the digital output type of the digital gray scale signal is the first digital output type generated by the duty ratio detection unit 111; when the Input control signal Input _ select is 1, the digital output type of the digital gray scale signal is the second digital output type generated by the frequency detection unit 112; when the Input control signal Input _ select is 2, the digital output type of the digital gray scale signal is the third digital output type generated by the voltage detecting unit 113. In this embodiment, the corresponding relationship between the Input control signal Input _ select and the digital output type of the digital gray scale signal is only schematically illustrated, and in other embodiments, the Input control signal Input _ select and the digital output type of the digital gray scale signal can be reasonably set as required.
Specifically, the input signal selection unit 114 may be a first multi-way selection switch MUX1, for example, MUX1 is a three-in, one-out multi-way selection switch, three input terminals of the first multi-way selection switch are respectively connected to the duty ratio detection unit 111, the frequency detection unit 112, and the voltage detection unit 113, and an output terminal of the first multi-way selection switch is connected to the grayscale voltage conversion sub-module 12. Of course, in other embodiments, the input signal selection unit 114 may also be three switches with single input and single output, and the on and off of the three switches are realized by inputting a control signal.
According to the LED driving chip, the appropriate detection unit is determined through the input signal selection unit to detect the first analog data signal, so that the flexibility is improved.
In one embodiment, the grayscale voltage conversion sub-module 12 stores a conversion relationship between the digital grayscale signal and the digital output signal in advance; the conversion relation between the two can be linear or nonlinear; the conversion relation may only include one corresponding relation, or may include a plurality of corresponding relations, and may be set reasonably as required.
As shown in fig. 18, the conversion relationship between the digital Gray-scale signal Gray level and the digital output signal Voltage is a non-linear relationship, the digital Gray-scale signals have a total of 256 Gray scales, which are Gray0, Gray1, Gray2 … Gray254 and Gray255, respectively, and the digital output signals corresponding to the Gray scales are shown in table 1. The conversion relationship between the digital gray scale signal and the digital output signal is only schematically illustrated in this embodiment, but not limited thereto, and in other embodiments, the conversion relationship may be reasonably determined according to an empirical value.
TABLE 1 conversion relationship between digital gray-scale signals and digital output signals
| Gray | Gray0 | Gray1 | Gray2 | … | Gray254 | Gray255 |
| Voltage | 2.0 | 2.1 | 2.2 | … | 8.1 | 8.8 |
In one embodiment, the gray voltage conversion sub-module 12 further includes: and the conversion relation selection unit is used for determining the conversion relation between the digital gray-scale signal and the digital output signal according to the received conversion relation selection signal.
Specifically, the conversion relationship between the digital gray-scale signal and the digital output signal may be preset, a plurality of curves including the conversion relationship therebetween, such as gamma2.2, gamma0.8, and gamma1.0, may be set, and the conversion relationship may be reasonably set as required, which is only schematically described in this embodiment. After the conversion relation is set, the conversion relation is in one-to-one correspondence with the conversion relation selection signals to obtain the corresponding relation, and the conversion relation curve can be determined according to the conversion relation selection signals, so that the conversion relation between the digital gray scale signals and the digital output signals is determined. For example, if the conversion relation selection signal is 0, the corresponding conversion curve is gamma0.8, and the digital gray-scale signal is converted according to the gamma0.8 curve to obtain a digital output signal; if the conversion relation selection signal is 1, the corresponding conversion curve is gamma1.0, and the digital gray-scale signal is converted according to the gamma1.0 curve to obtain a digital output signal; if the conversion relation selection signal is 2, the corresponding conversion curve is gamma2.2, and the digital gray-scale signal is converted according to the gamma2.2 curve to obtain a digital output signal.
In one embodiment, as shown in fig. 5, the output voltage generation submodule 13 includes: a pulse width modulation unit 131 connected to the grayscale voltage conversion sub-module 12, and configured to generate a first analog output type of a second analog data signal according to the digital output signal; and the pulse amplitude modulation unit 132 is connected to the gray scale voltage conversion sub-module 12, and is configured to generate a second analog output type of a second analog data signal according to the digital output signal.
Specifically, the first analog output type is a PWM output, and the second analog output type is a PAM output. The analog output type of the second analog data signal may be determined according to the LED and driving time interval conditions, that is, whether the PWM output or the PAM output is determined according to the above conditions. The analog output type can be determined by the period length, the voltage size and the like of the target voltage. For example, when the current period is short, the PAM mode may be selected because the pulse width of PWM at the time of the time end is too small to sufficiently separate the low gray levels. The PWM method may be used if the voltage value of the driving voltage is relatively low because PAM cannot sufficiently separate low gray scales when the voltage is low.
Specifically, the pulse width modulation unit 131 may include a first digital-to-analog converter DAC1 and a comparator, the first digital-to-analog converter DAC1 is connected to the gray voltage conversion sub-module to convert the received digital gray scale signals into analog signals, and the comparator is connected to the first digital-to-analog converter DAC1 to convert the analog signals output from the first digital-to-analog converter DAC1 into PWM output signals, which are the first analog output type of the second analog data signals. As shown in fig. 19, the inverting Input terminal of the comparator is connected to the rectangular wave Sawtooth, the non-inverting Input terminal of the comparator is connected to the analog signal Input message output by the first DAC1, the output terminal of the comparator outputs a PWM signal, and a specific waveform diagram of the PWM signal is shown in fig. 20.
Specifically, the pulse amplitude modulation unit 132 may include a second digital-to-analog converter DAC2 and a pulse amplitude modulator, the second digital-to-analog converter DAC2 being connected to the gray voltage conversion sub-module to convert the received digital gray scale signals into analog signals, and the pulse amplitude modulator being connected to the second digital-to-analog converter DAC 2. As shown in fig. 21, the Pulse amplitude modulator includes a Low Pass Filter (Low Pass Filter), a Pulse Train Generator (Pulse Train Generator), a multiplier (multipier), and a Pulse Shaping Network (Pulse Shaping Network), an output terminal of the second digital-to-Analog converter DAC2 is connected to the Low Pass Filter, an Analog signal single output by the second digital-to-Analog converter DAC2 is input to the Low Pass Filter, the Low Pass Filter is connected to the multiplier, the Pulse Train Generator is also connected to the multiplier, an output terminal of the multiplier is connected to the Pulse Shaping Network, and an output terminal of the Pulse Shaping Network outputs a PAM signal; a specific waveform diagram of the PAM signal is shown in fig. 22.
It should be noted that, in this embodiment, both the pulse width modulation unit and the pulse amplitude modulation unit are provided with digital-to-analog converters, in other embodiments, two digital-to-analog converters in the pulse width modulation unit and the pulse amplitude modulation unit may be externally arranged, that is, the pulse width modulation unit only includes a comparator, and the pulse amplitude modulation unit only includes a pulse amplitude modulator; and only one external digital-to-analog converter can be arranged, the input of the external digital-to-analog converter is connected with the gray-scale voltage conversion submodule, and the output end of the digital-to-analog converter is respectively connected with the pulse width modulation unit and the pulse amplitude modulation unit.
In one embodiment, as shown in fig. 6, the output voltage generation submodule 13 further includes: and an Output signal selection unit 133, connected to the pulse width modulation unit 131 and the pulse amplitude modulation unit 132, for determining an analog Output type of the second analog data signal according to the received Output control signal Output _ select.
Specifically, the corresponding relationship between the Output control signal Output _ select and the analog Output type of the second analog data signal may be preset, and then the analog Output type of the second analog data signal may be determined according to the preset corresponding relationship. For example, when the Output control signal Output _ select is 0, the analog Output type of the second analog data signal is the first analog Output type generated by the pulse width modulation unit 131; when the Output control signal Output _ select is 1, the analog Output type of the second analog data signal is the second analog Output type generated by the pulse amplitude modulation unit 132. In this embodiment, the corresponding relationship between the Output control signal Output _ select and the analog Output type of the second analog data signal is only schematically illustrated, and in other embodiments, the Output control signal Output _ select and the analog Output type of the second analog data signal can be reasonably set as required.
Specifically, the output signal selection unit 133 may include a second multiplexing switch MUX2 and a third multiplexing switch MUX3, such as a MUX2 being a one-in two-out multiplexing switch and a MUX3 being a two-in one-out multiplexing switch. The input end of the second multi-way switch is connected to the gray scale voltage conversion sub-module 12, and two output ends of the second multi-way switch are respectively connected to the pulse width modulation unit 131 and the pulse amplitude modulation unit 132. Two input ends of the third multi-way selection switch are respectively connected with the pulse width modulation unit 131 and the pulse amplitude modulation unit 132, and an output end of the third multi-way selection switch outputs a second analog data signal. Of course, in other embodiments, the output signal selection unit 133 may also be composed of a plurality of single-in single-out switches, which is only schematically illustrated in this embodiment, but not limited thereto, and may be reasonably set according to actual needs.
According to the LED driving chip, the appropriate output mode is determined through the output signal selection unit, various AM controls of the LED are achieved, and control flexibility and accuracy are improved.
In one embodiment, as shown in fig. 7, the LED driving chip further includes: and the first switch module 2 is connected with the scanning signal and logic control module 1 and is used for generating an LED control signal according to the scanning signal and the second analog data signal.
Specifically, as shown in fig. 10, the first switch module 2 may be an N-type TFT switch transistor T1, the gate of T1 is connected to the scan signal, the drain of T1 is connected to the second analog data signal output by the logic control module 1, and the source of T1 is connected to the LED. The LED control signal, i.e., the signal outputted from the source of T1, is derived from the scan signal and the second analog data signal. In other embodiments, the first switch module may also be a P-type TFT switch tube, or other types of switch tubes, such as MOS tubes, etc., and this embodiment is only schematically illustrated, and is not limited thereto, and the first switch module may be reasonably arranged as required.
In one embodiment, as shown in fig. 8, the LED driving chip further includes: and the second switch module 3 is connected with the first switch module 2 and the LED and is used for controlling the LED to be switched on and off according to the LED control signal.
Specifically, as shown in fig. 10, the second switch module 3 may be an N-type TFT switch transistor T2, the gate of T2 is connected to the LED control signal, the drain of T2 is connected to the LED, and the source of T2 is connected to the ground. And the LED is switched on and off according to the LED control signal. In other embodiments, the second switch module may also be a P-type TFT switch tube, or other types of switch tubes, such as MOS tubes, etc., and this embodiment is only schematically illustrated, and is not limited thereto, and the second switch module may be reasonably arranged as required.
In one embodiment, as shown in fig. 9, the LED driving chip further includes: and the charge storage module 4 is connected with the first switch module 2 and is used for storing the LED control signal.
Specifically, as shown in fig. 10, the charge storage module 4 may be a storage capacitor Cst, a first terminal of the storage capacitor Cst is connected to the output terminal of the first switch module 2, and a first terminal of the storage capacitor Cst is connected to the ground line. The charge storage module in this embodiment is only schematically described, and not taken as an example, and in other embodiments, the charge storage module may be reasonably arranged as required.
It should be noted that, the N-type switching tube and the P-type switching tube have different connection modes with the LED due to different characteristics of the tubes, and the connection relationship needs to be determined reasonably according to the type of the switching tube, and the connection of the LED and the connection of the charge storage module also need to be adjusted adaptively.
The operation of the LED driving chip will be described in detail below, as shown in fig. 11 to 14.
As shown in fig. 11, the input first Analog data signal is an Analog voltage (Analog voltage), and the second Analog data signal converted by the LED driving chip is a PAM signal. The voltage value (Analog voltage) of the first Analog data signal varies, and thus, the voltage can be detected. In a first period of 0-1H, the voltage value of an input first analog data signal is 1.5V, a digital gray scale signal is generated after passing through a gray scale information coding submodule, and the gray scale value is 511; the value of the digital output signal generated after the conversion of the gray scale voltage conversion submodule is 6; and finally, outputting the voltage value of the second analog data signal to be 6V through the output voltage generation submodule. In the second period 1H-2H, the voltage value of the input first analog data signal is 3V, and a digital gray scale signal is generated after passing through the gray scale information coding submodule, wherein the gray scale value is 1023; the value of the digital output signal generated after the conversion of the gray scale voltage conversion submodule is 8; and finally, outputting the voltage value of the second analog data signal to be 8V through the output voltage generation submodule. In other embodiments, the output second analog data signal may also be a PWM signal, and the working process is similar thereto, which is not described herein again.
As shown in fig. 12, the duty ratio of the input first analog data signal varies in different periods, so that the duty ratio can be detected. In a first period of 0-1H, the duty ratio of an input first analog data signal is 50%, a digital gray scale signal is generated after passing through a gray scale information coding submodule, and the gray scale value is 511; the value of the digital output signal generated after the conversion of the gray scale voltage conversion submodule is 6; and finally, outputting the voltage value of the second analog data signal to be 6V through the output voltage generation submodule. In the second period 1H-2H, the duty ratio of the input first analog data signal is 80%, and a digital gray scale signal is generated after passing through a gray scale information coding submodule, wherein the gray scale value is 1023; the value of the digital output signal generated after the conversion of the gray scale voltage conversion submodule is 8; and finally, outputting the voltage value of the second analog data signal to be 8V through the output voltage generation submodule. In other embodiments, the output second analog data signal may also be a PWM signal, and the working process is similar thereto, which is not described herein again.
As shown in fig. 13, the frequency of the input first analog data signal varies in different periods, so that the frequency can be detected. In a first period of 0-1H, the frequency of an input first analog data signal is 1MHz, a digital gray scale signal is generated after passing through a gray scale information coding submodule, and the gray scale value is 511; the value of the digital output signal generated after the conversion of the gray scale voltage conversion submodule is 6; and finally, outputting the voltage value of the second analog data signal to be 6V through the output voltage generation submodule. In the second period 1H-2H, the frequency of the input first analog data signal is 2MHz, and a digital gray scale signal is generated after passing through a gray scale information coding submodule, wherein the gray scale value is 1023; the value of the digital output signal generated after the conversion of the gray scale voltage conversion submodule is 8; and finally, outputting the voltage value of the second analog data signal to be 8V through the output voltage generation submodule. PAM control of the LED can be realized through the process.
As shown in fig. 14, the frequency of the input first analog data signal varies in different periods, so that the frequency can be detected. In a first period of 0-1H, the frequency of an input first analog data signal is 1MHz, a digital gray scale signal is generated after passing through a gray scale information coding submodule, and the gray scale value is 511; the value of the digital output signal generated after the conversion of the gray scale voltage conversion submodule is 60; and finally, the duty ratio of the second analog data signal output by the output voltage generation submodule is 60%. In the second period 1H-2H, the frequency of the input first analog data signal is 2MHz, and a digital gray scale signal is generated after passing through a gray scale information coding submodule, wherein the gray scale value is 1023; the value of the digital output signal generated after the conversion of the gray scale voltage conversion submodule is 80; and finally, outputting a second analog data signal by the output voltage generation submodule, wherein the duty ratio of the second analog data signal is 80%. The PWM control of the LED can be realized through the process.
The embodiment of the utility model provides a still provide a backlight unit, as shown in FIG. 15, include: a back plate 151; a light source disposed on the back plate 151 and including a plurality of LEDs 152 arranged in an array; as described in any of the above embodiments, the LED driving chips 153 are disposed on the back plate 151, and correspond to the LEDs 152 one to one.
It should be noted that the LED152 in fig. 15 is composed of a plurality of mini LEDs connected in series, in which case the plurality of mini LEDs are regarded as one LED 152.
In an embodiment, the backplane may be a Printed Circuit Board (PCB) or a thin film transistor backplane, such as an LTPS backplane, an α -Si backplane, and the like, which is only schematically described in this embodiment and is not limited thereto, and in other embodiments, the backplane may also be another type of backplane in the prior art, such as a glass backplane.
In an embodiment, the LED may be a mini LED or a micro LED, which is only schematically described in the embodiment and is not limited thereto.
In an embodiment, when the LED driving chip does not include the first switching module, the first switching module may be a discrete device; the first switch module can also be directly arranged on the thin film transistor backboard, and can be formed by adopting a laminated film layer.
In an embodiment, when the LED driving chip does not include the second switch module, the second switch module may be a discrete device, or the second switch module may be directly formed on the tft backplane, and may specifically be formed by a laminated film.
In an embodiment, when the LED driving chip does not include the charge storage module, the charge storage module may be a discrete device or may be directly fabricated on the back plate. Specifically, the charge storage module can be formed by using a film layer in a PCB (printed Circuit Board) or a film layer in a backboard of a thin film transistor.
The backlight unit adopts the LED driving chip, realizes flexible selection of the AM driving mode of the LED, can select a proper control mode according to the actual working condition of the LED, and improves the accuracy and flexibility of LED control.
The embodiment of the utility model provides a still provide a display panel, include: a backlight unit as described in any of the embodiments. The display panel adopts the LED driving chip, realizes flexible selection of the AM driving mode of the LED, can select a proper control mode according to the actual working condition of the LED, and improves the accuracy and flexibility of LED control.
In one embodiment, the display panel may be an LCD display panel, but may also be other types of display panels, for example, all display panels that require backlighting.
The embodiment of the utility model provides a still provide a display device, include as above-mentioned display panel. The display device adopts the LED driving chip, realizes flexible selection of the AM driving mode of the LED, can select a proper control mode according to the actual working condition of the LED, and improves the accuracy and flexibility of LED control.
The display device can be a product or a component with a display function, such as a mobile phone, a flat panel, a television, a display, a palm computer, an ipod, a digital camera, a navigator, a vehicle-mounted display screen and the like.
Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations fall within the scope defined by the appended claims.
Claims (12)
1. An LED driving chip, wherein the LED driving chip is connected to an LED for controlling the LED, the LED driving chip comprises:
the logic control module (1) is used for receiving a first analog data signal shared by one row or one column of the position of the LED and converting the first analog data signal into a second analog data signal for individually controlling the LED;
the logic control module (1) comprises:
the gray information coding submodule (11) is used for coding the first analog data signal to generate a digital gray scale signal;
the gray scale voltage conversion submodule (12) is connected with the gray scale information coding submodule (11) and is used for generating a digital output signal according to the digital gray scale signal;
and the output voltage generation submodule (13) is connected with the gray scale voltage conversion submodule (12) and is used for generating a second analog data signal according to the digital output signal.
2. The LED driving chip according to claim 1, wherein the grey scale information encoding sub-module (11) comprises:
the duty ratio detection unit (111) is used for detecting duty ratio information of the first analog data signal and generating a first digital output type of the digital gray scale signal by encoding according to the duty ratio information;
the frequency detection unit (112) is used for detecting frequency information of the first analog data signal and generating a second digital output type of the digital gray-scale signal by encoding according to the frequency information;
and the voltage detection unit (113) is used for detecting the voltage information of the first analog data signal and generating a third digital output type of the digital gray-scale signal by encoding according to the voltage information.
3. The LED driving chip according to claim 2, wherein the gray scale information encoding sub-module (11) further comprises:
and the input signal selection unit (114) is connected with the duty ratio detection unit (111), the frequency detection unit (112) and the voltage detection unit (113) and is used for determining the digital output type of the digital gray-scale signal according to the received input control signal.
4. The LED driving chip according to claim 1, wherein the gray voltage conversion sub-module (12) is further configured to determine a conversion relationship between the digital gray scale signal and the digital output signal according to the received conversion relationship selection signal.
5. The LED driving chip according to claim 1, wherein the output voltage generation submodule (13) comprises:
the pulse width modulation unit (131) is connected with the gray scale voltage conversion submodule (12) and is used for generating a first analog output type of a second analog data signal according to the digital output signal;
and the pulse amplitude modulation unit (132) is connected with the gray scale voltage conversion submodule (12) and is used for generating a second analog output type of a second analog data signal according to the digital output signal.
6. The LED driving chip according to claim 5, wherein the output voltage generation submodule (13) further comprises:
and the output signal selection unit (133) is connected with the pulse width modulation unit (131) and the pulse amplitude modulation unit (132) and is used for determining the analog output type of the second analog data signal according to the received output control signal.
7. The LED driving chip according to any one of claims 1 to 6, further comprising:
and the first switch module (2) is connected with a scanning signal and the logic control module (1) and is used for generating an LED control signal according to the scanning signal and the second analog data signal.
8. The LED driving chip according to claim 7, further comprising:
and the second switch module (3) is connected with the first switch module (2) and the LED and is used for controlling the LED to be switched on and off according to the LED control signal.
9. The LED driving chip according to claim 7, further comprising:
and the charge storage module (4) is connected with the first switch module (2) and is used for storing the LED control signal.
10. A backlight unit, comprising:
a back plate;
the light source is arranged on the back plate and comprises a plurality of LEDs which are arranged in an array;
the plurality of LED driver chips of any of claims 1-9 disposed on the backplane in one-to-one correspondence with the plurality of LEDs.
11. A display panel comprising the backlight unit according to claim 10.
12. A display device characterized by comprising the display panel according to claim 11.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112863452A (en) * | 2021-02-09 | 2021-05-28 | 河南省华锐光电产业有限公司 | Light-emitting substrate, driving method thereof and display device |
| CN114038393A (en) * | 2021-07-16 | 2022-02-11 | 重庆康佳光电技术研究院有限公司 | Pixel circuit and display panel |
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2020
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112863452A (en) * | 2021-02-09 | 2021-05-28 | 河南省华锐光电产业有限公司 | Light-emitting substrate, driving method thereof and display device |
| CN112863452B (en) * | 2021-02-09 | 2021-11-23 | 河南省华锐光电产业有限公司 | Light-emitting substrate, driving method thereof and display device |
| CN114038393A (en) * | 2021-07-16 | 2022-02-11 | 重庆康佳光电技术研究院有限公司 | Pixel circuit and display panel |
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