LED driver chip, backlight unit, display panel and display device

Abstract

The present invention discloses an LED driver chip, a backlight unit, a display panel and a display device, wherein the LED driver chip is connected to an LED and used to control the LED, and includes: a logic control module, which is used to receive a first analog data signal shared by a row or a column at the position of the LED and convert the first analog data signal into a second analog data signal for individually controlling the LED; the logic control module includes: a grayscale information encoding submodule, which is used to encode the first analog data signal to generate a digital grayscale signal; a grayscale voltage conversion submodule, which is connected to the grayscale information encoding submodule and used to generate a digital output signal according to the digital grayscale signal; an output voltage generation submodule, which is connected to the grayscale voltage conversion submodule and used to generate a second analog data signal according to the digital output signal. The above-mentioned LED driver chip controls the LED individually, realizes a variety of different AM backlight driving modes, and makes the control of the LED more accurate and flexible.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to an LED driver chip, a backlight unit, a display panel and a display device. Background Art

[0002] Currently, the backlighting methods of display devices can be roughly divided into two types, one type is a passive matrix (PM) backlighting method, and the other type is an active matrix (AM) backlighting method.

[0003] The cost of PM backlight is relatively low and it is easy to implement technically. However, as the display resolution increases, the scanning time of each line per unit time is shortened, especially when it is applied to large-size display devices, PM backlight is difficult to implement. In order to solve the above problems, the display device can be divided into several areas for driving. The driving structure of this method is relatively complex, and there are brightness differences between the divided areas. The AM backlight method can achieve better brightness uniformity and contrast, as well as higher resolution. Therefore, display devices with AM backlight are becoming more and more popular. Summary of the invention

[0004] Based on this, the embodiments of the present invention provide a novel active matrix backlight driving and controlling LED driver chip, backlight unit, display panel and display device.

[0005] According to a first aspect, an embodiment of the present invention provides an LED driver chip, which is connected to an LED and is used to control the LED. The LED driver chip includes: a logic control module, which is used to receive a first analog data signal shared by a row or a column at the position of the LED and convert the first analog data signal into a second analog data signal for individually controlling the LED; the logic control module includes: a grayscale information encoding submodule, which is used to encode the first analog data signal to generate a digital grayscale signal; a grayscale voltage conversion submodule, which is connected to the grayscale information encoding submodule and is used to generate a digital output signal according to the digital grayscale signal; an output voltage generation submodule, which is connected to the grayscale voltage conversion submodule and is used to generate a second analog data signal according to the digital output signal.

[0006] Optionally, the grayscale information encoding submodule includes: a duty cycle detection unit, used to detect the duty cycle information of the first analog data signal, and encode according to the duty cycle information to generate a first digital output type of the digital grayscale signal; a frequency detection unit, used to detect the frequency information of the first analog data signal, and encode according to the frequency information to generate a second digital output type of the digital grayscale signal; a voltage detection unit, used to detect the voltage information of the first analog data signal, and encode according to the voltage information to generate a third digital output type of the digital grayscale signal.

[0007] Optionally, the grayscale information encoding submodule further includes: an input signal selection unit connected to the duty cycle detection unit, the frequency detection unit and the voltage detection unit, and configured to determine a digital output type of the digital grayscale signal according to a received input control signal.

[0008] Optionally, the grayscale voltage conversion submodule is further used to determine the conversion relationship between the digital grayscale signal and the digital output signal according to a received conversion relationship selection signal.

[0009] Optionally, the output voltage generating submodule includes: a pulse width modulation unit connected to the grayscale voltage conversion submodule, for generating a first analog output type of a second analog data signal according to the digital output signal; and a pulse amplitude modulation unit connected to the grayscale voltage conversion submodule, for generating a second analog output type of a second analog data signal according to the digital output signal.

[0010] Optionally, the output voltage generating submodule further includes: an output signal selecting unit connected to the pulse width modulation unit and the pulse amplitude modulation unit, and configured to determine the analog output type of the second analog data signal according to a received output control signal.

[0011] Optionally, the LED driver chip further includes: a first switch module, connected to the scan signal and the logic control module, and configured to generate an LED control signal according to the scan signal and the second analog data signal.

[0012] Optionally, the LED driver chip further includes: a second switch module connected to the first switch module and the LED, and configured to control the on and off of the LED according to the LED control signal.

[0013] Optionally, the LED driver chip further includes: a charge storage module connected to the first switch module and used to store the LED control signal.

[0014] According to the second aspect, an embodiment of the present invention provides a backlight unit, comprising: a back panel; a light source, arranged on the back panel, comprising a plurality of LEDs arranged in an array; a plurality of LED driver chips as described in any one of the first aspects of the present invention, arranged on the back panel, corresponding one-to-one to the plurality of LEDs.

[0015] According to a third aspect, an embodiment of the present invention provides a display panel, comprising the backlight unit as described in the second aspect of the present invention.

[0016] According to a fourth aspect, an embodiment of the present invention provides a display device, comprising the display panel as described in the third aspect of the present invention.

[0017] The technical solution of the present invention has the following advantages:

[0018] The LED driver chip provided by the present invention is connected to an LED and used to control the LED. The LED driver chip includes: a logic control module, which is used to receive a first analog data signal shared by a row or a column at the position of the LED and convert the first analog data signal into a second analog data signal for individually controlling the LED; the logic control module includes: a grayscale information encoding submodule, which is used to encode the first analog data signal to generate a digital grayscale signal; a grayscale voltage conversion submodule, which is connected to the grayscale information encoding submodule and is used to generate a digital output signal according to the digital grayscale signal; an output voltage generation submodule, which is connected to the grayscale voltage conversion submodule and is used to generate a second analog data signal according to the digital output signal. The above-mentioned LED driver chip receives the first analog data signal through the logic control module and converts the first analog data signal into the second analog data signal, and individually controls the LED, realizing a variety of different AM backlight driving methods, making the control of the LED more accurate and flexible. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A schematic diagram of a specific example of AM driving LED in the prior art;

[0021] Figure 2 is a schematic diagram of a specific example of an LED driver chip according to an embodiment of the present invention;

[0022] Figure 3 is a schematic diagram of another specific example of the LED driver chip according to the embodiment of the present invention;

[0023] Figure 4 is a schematic diagram of another specific example of the LED driver chip according to the embodiment of the present invention;

[0024] Figure 5 is a schematic diagram of another specific example of the LED driver chip according to the embodiment of the present invention;

[0025] Figure 6 is a schematic diagram of another specific example of the LED driver chip according to the embodiment of the present invention;

[0026] Figure 7 is a schematic diagram of another specific example of the LED driver chip according to the embodiment of the present invention;

[0027] Figure 8 is a schematic diagram of another specific example of the LED driver chip according to the embodiment of the present invention;

[0028] Fig. 9 is a schematic diagram of another specific example of the LED driver chip according to the embodiment of the present invention;

[0029] Fig.10 is a schematic diagram of another specific example of the LED driver chip according to the embodiment of the present invention;

[0030] Fig.11 A schematic diagram of a specific example of the working process of the LED driver chip according to an embodiment of the present invention;

[0031] Fig.12 A schematic diagram of another specific example of the working process of the LED driver chip according to an embodiment of the present invention;

[0032] Fig.13 A schematic diagram of another specific example of the working process of the LED driver chip according to an embodiment of the present invention;

[0033] Fig.14 A schematic diagram of another specific example of the working process of the LED driver chip according to an embodiment of the present invention;

[0034] Fig.15 is a schematic diagram of a specific example of a backlight unit according to an embodiment of the present invention;

[0035] Fig.16 is a schematic diagram of a specific example of a duty cycle detection unit according to an embodiment of the present invention;

[0036] Fig.17 is a schematic diagram of a specific example of a frequency detection unit according to an embodiment of the present invention;

[0037] Fig.18 A schematic diagram of a specific example of the conversion relationship between a digital grayscale signal and a digital output signal according to an embodiment of the present invention;

[0038] Fig.19 is a schematic diagram of a specific example of a pulse width modulation unit according to an embodiment of the present invention;

[0039] Fig. 20 A schematic diagram of a specific example of a pulse width modulation unit generating a PWM signal according to an embodiment of the present invention;

[0040] Fig.21 is a schematic diagram of a specific example of a pulse amplitude modulation unit according to an embodiment of the present invention;

[0041] Fig. 22 The figure 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

[0042] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0043] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0044] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0046] At present, the commonly used AM backlight driving method can realize the AM driving of LED through 2T1C, such as Figure 1 As shown, the control end of the first switch tube M1 is connected to the scan signal SCAN, the first end of the first switch tube M1 is connected to the data signal DATA, the second end of the first switch tube M1 is connected to the storage capacitor C1, the second end of the first switch tube M1 is also connected to the control end of the second switch tube M2, the second switch tube M2 is connected in series with the light emitting diode (Light Emitting Diode, abbreviated as LED) D1, and the light emitting diode D1 is turned on and off by controlling the second switch tube M2. The inventor found that if the light emitting diode is controlled only by 2T1C, the control type of the light emitting diode is consistent with the type of the data signal, that is, if the data signal is a PWM signal, the control mode of the light emitting diode is PWM control, and if the data signal is a PAM signal, the control mode of the light emitting diode is PAM control. Due to the different driving characteristics of PAM and PWM, when the driving time is relatively short, PWM control cannot achieve low grayscale distinction, resulting in insufficient low grayscale performance. In this case, PAM driving effect is better; when the driving time is relatively long, PWM driving has better control ability than PAM driving; therefore, in practical applications, only controlling the light-emitting diode through 2T1C leads to poor control effect. Therefore, the embodiment of the present invention provides a new type of active matrix backlight driving control LED driver chip, backlight unit, display panel and display device to provide a variety of different AM backlight driving methods, thereby improving the accuracy and flexibility of LED control.

[0047] The embodiment of the present invention provides an LED driver chip, such as Figure 2 As shown, the LED driver chip is connected to an LED for controlling the LED, and the LED driver chip includes a logic control module 1 for receiving a first analog data signal common to a row or a column at the position where the LED is located and converting the first analog data signal into a second analog data signal for individually controlling the LED. The logic control module 1 includes:

[0048] A gray level information decoding submodule 11, configured to encode the first analog data signal to generate a digital gray scale signal;

[0049] A gray level to voltage conversion submodule 12, connected to the gray information encoding submodule 11, for generating a digital output signal according to the digital gray scale signal;

[0050] The output voltage generation submodule 13 is connected to the grayscale voltage conversion submodule 12 and is used to generate a second analog data signal according to the digital output signal.

[0051] In one embodiment, if the scanning signal of the LED is row-driven and the data signal is column-driven, the logic control module receives a data signal common to a column of LEDs, which is the first analog data signal, that is, the first analog data signal is a data signal common to a column of LEDs; of course, in other embodiments, if the scanning 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 the LEDs connected to the LED driver chip.

[0052] In one embodiment, the first analog data signal may be a PWM signal or an analog voltage signal; this embodiment is only for illustrative purposes and is not limited thereto. The second analog data signal may be a PWM signal or a PAM signal; this embodiment is only for illustrative purposes and is not limited thereto.

[0053] The LED driver chip receives the first analog data signal through the logic control module and converts the first analog data signal into a second analog data signal, thereby realizing a variety of different AM backlight driving modes, making the control of the LED more accurate and flexible.

[0054] In one embodiment, if Figure 3 As shown, the grayscale information encoding submodule 11 includes: a duty cycle detection unit 111, used to detect the duty cycle information of the first analog data signal, and encode according to the duty cycle information to generate a first digital output type of a digital grayscale signal; a frequency detection unit 112, used to detect the frequency information of the first analog data signal, and encode according to the frequency information to generate a second digital output type of the digital grayscale signal; a voltage detection unit 113, used to detect the voltage information of the first analog data signal, and encode according to the voltage information to generate a third digital output type of the digital grayscale signal.

[0055] Specifically, the duty cycle detection unit 111 may be composed of a first counter Counter1 and a second counter Counter2, wherein the first counter Counter1 is used to count the number of pulses N1 of the detection clock signal (Detection clock) in a high level time period in a cycle, and the second counter Counter2 is used to count the number of pulses N2 of the detection clock signal (Detection clock) in a low level time period in a cycle, and the duty cycle of the input PWM signal in the cycle is N1 / (N1+N2). Of course, in other embodiments, the second counter Counter2 may also count the number of pulses N3 of the detection clock signal in a cycle, and the duty cycle is N1 / N3. It should be noted that in order to reduce the amount of calculation, the counter is cleared at the end of a cycle.

[0056] like Fig.16 As shown, the duty cycle of the input PWM signal is detected by detecting the clock signal. The number of pulses of the detection clock signal in the high-level time period of the first cycle is 6, and the number of pulses of the detection clock signal in the low-level time period is 4. The duty cycle of the input PWM signal in the first cycle is 6 / (6+4)=60%; the number of pulses of the detection clock signal in the high-level time period of the second cycle is 8, and the number of pulses of the detection clock signal in the low-level time period is 2. The duty cycle of the input PWM signal in the second cycle is 8 / (8+2)=80%.

[0057] Specifically, the frequency detection unit 112 may be composed of a third counter Counter3, which is used to count the number of pulses of the input PWM signal to obtain the number N4 of pulses of the input PWM signal in one cycle, and the frequency of the input PWM signal is 1 / N4.

[0058] like Fig.17 As shown, the number of pulses of the input PWM signal in the first cycle is 11, and the frequency of the input PWM signal in the first cycle is 1 / 11; the number of pulses of the input PWM signal in the second cycle is 4, and the frequency of the input PWM signal in the second cycle is 1 / 4.

[0059] Specifically, the voltage detection unit 113 can be an analog-to-digital converter (ADC), such as a successive approximation ADC, an integrating ADC, a ∑-Δ ADC, or a pipeline ADC. This embodiment is only used for illustrative purposes and is not limited thereto. In actual applications, it can be reasonably set according to needs.

[0060] The duty cycle detection unit 111, the frequency detection unit 112 and the voltage detection unit 113 can automatically detect the waveform of the input first analog data signal. Different input waveforms have different characteristics. The detection unit is determined according to the input waveform, and the digital output type of the digital grayscale signal is obtained. For example, if the input waveform of the first analog data signal changes according to the voltage duty cycle (different duty cycles correspond to different grayscales), the duty cycle detection unit 111 performs duty cycle detection on it; if the input waveform of the first analog data signal changes according to the voltage frequency (different frequencies correspond to different grayscales), the frequency detection unit 112 performs frequency detection on it; if the input waveform of the first analog data signal changes according to the voltage magnitude (different voltage magnitudes correspond to different grayscales), the voltage detection unit 113 performs voltage detection on it.

[0061] The LED driver chip performs automatic waveform detection on the input first analog data signal through the duty cycle detection unit 111, the frequency detection unit 112 and the voltage detection unit 113, so that the detection is more accurate, thereby making the LED control more precise.

[0062] In one embodiment, if Figure 4 As shown, the grayscale information encoding submodule 11 further includes: an input signal selection unit 114 connected to the duty cycle detection unit 111, the frequency detection unit 112 and the voltage detection unit 113, and configured to determine the digital output type of the digital grayscale signal according to the received input control signal Input_select.

[0063] Specifically, the corresponding relationship between the input control signal Input_select and the digital output type of the digital grayscale signal can be pre-set, and then the digital output type of the digital grayscale signal is determined by the set corresponding relationship. For example, when the input control signal Input_select is 0, the digital output type of the digital grayscale signal is the first digital output type generated by the duty cycle detection unit 111; when the input control signal Input_select is 1, the digital output type of the digital grayscale 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 grayscale signal is the third digital output type generated by the voltage detection unit 113. In this embodiment, the corresponding relationship between the input control signal Input_select and the digital output type of the digital grayscale signal is only schematically illustrated. In other embodiments, it can be reasonably set as needed.

[0064] Specifically, the input signal selection unit 114 may be a first multiplexer switch MUX1. For example, MUX1 is a three-input single-output multiplexer switch. The three input terminals of the first multiplexer switch are respectively connected to the duty cycle detection unit 111, the frequency detection unit 112, and the voltage detection unit 113. The output terminal of the first multiplexer switch is connected to the grayscale voltage conversion submodule 12. Of course, in other embodiments, the input signal selection unit 114 may also be three single-input single-output switches. The three switches are turned on and off by inputting control signals. This embodiment is only schematically described and is not limited thereto. The specific configuration may be reasonable according to actual needs.

[0065] The LED driver chip determines a suitable detection unit to detect the first analog data signal through the input signal selection unit, thereby improving flexibility.

[0066] In one embodiment, the grayscale voltage conversion submodule 12 pre-stores the conversion relationship between the digital grayscale signal and the digital output signal; the conversion relationship between the two can be linear or non-linear; the conversion relationship can include only one corresponding relationship or multiple corresponding relationships, which can be reasonably set according to needs.

[0067] like Fig.18 As shown in Table 1, the conversion relationship between the digital grayscale signal Gray level and the digital output signal Voltage is a nonlinear relationship. The digital grayscale signal has a total of 256 grayscales, namely Gray0, Gray1, Gray2...Gray254, Gray255. The digital output signal corresponding to each grayscale is shown in Table 1. In this embodiment, the conversion relationship between the digital grayscale signal and the digital output signal is only schematically illustrated, and is not limited thereto. In other embodiments, it can be reasonably determined based on empirical values.

[0068] Table 1 Conversion relationship between digital grayscale signal and digital output signal

[0069] Gray Gray0 Gray1 Gray2 ... Gray254 Gray255 Voltage 2.0 2.1 2.2 ... 8.1 8.8

[0070] In one embodiment, the grayscale voltage conversion submodule 12 further includes: a conversion relationship selection unit, configured to determine a conversion relationship between the digital grayscale signal and the digital output signal according to a received conversion relationship selection signal.

[0071] Specifically, the conversion relationship between the digital grayscale signal and the digital output signal can be pre-set, and multiple curves containing the conversion relationship between the two can be set, such as gamma2.2, gamma0.8, gamma1.0, etc. The conversion relationship can be reasonably set according to the needs, and this embodiment is only schematically described. After the conversion relationship is set, the conversion relationship is matched with the conversion relationship selection signal one by one to obtain a corresponding relationship. The conversion relationship curve can be determined according to the conversion relationship selection signal, and then the conversion relationship between the digital grayscale signal and the digital output signal can be determined. For example, if the conversion relationship selection signal is 0, the corresponding conversion curve is gamma0.8, and the digital grayscale signal is converted according to the gamma0.8 curve to obtain a digital output signal; if the conversion relationship selection signal is 1, the corresponding conversion curve is gamma1.0, and the digital grayscale signal is converted according to the gamma1.0 curve to obtain a digital output signal; if the conversion relationship selection signal is 2, the corresponding conversion curve is gamma2.2, and the digital grayscale signal is converted according to the gamma2.2 curve to obtain a digital output signal.

[0072] In one embodiment, if Figure 5 As shown, the output voltage generating submodule 13 includes: a pulse width modulation unit 131, connected to the grayscale voltage conversion submodule 12, for generating a first analog output type of a second analog data signal according to a digital output signal; a pulse amplitude modulation unit 132, connected to the grayscale voltage conversion submodule 12, for generating a second analog output type of a second analog data signal according to the digital output signal.

[0073] Specifically, the first analog output type is PWM output, and the second analog output type is PAM output. The analog output type of the second analog data signal can be determined according to the LED and the driving timing conditions, that is, whether it is PWM output or PAM output can be determined according to the above conditions. Specifically, the analog output type can be determined by the length of the target voltage cycle, the voltage size, etc. For example, when the current cycle is very small, the PAM mode can be selected, because the pulse width of PWM is too small at the end of time, and the low gray scale cannot be fully distinguished. If the voltage value of the driving voltage is relatively low, the PWM mode can be used, because PAM cannot fully distinguish the low gray scale when the voltage is low.

[0074] 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 grayscale voltage conversion submodule to convert the received digital grayscale signal into an analog signal. The comparator is connected to the first digital-to-analog converter DAC1 to convert the analog signal output by the first digital-to-analog converter DAC1 into a PWM output signal through the comparator. The PWM output signal is also the first analog output type of the second analog data signal. Fig.19As shown, the inverting input of the comparator is connected to the rectangular wave Sawtooth, the non-inverting input is connected to the analog signal Input message output by the first digital-to-analog converter DAC1, and the output of the comparator outputs a PWM signal. The specific waveform of the PWM signal is shown in Fig. 20 shown.

[0075] 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 is connected to the grayscale voltage conversion submodule, converts the received digital grayscale signal into an analog signal, and the pulse amplitude modulator is connected to the second digital-to-analog converter DAC2. Fig.21 As shown, the pulse amplitude modulator includes a low pass filter (Low Pass Filter), a pulse train generator (Pulse Train Generator), a multiplier (Multipiler) and a pulse shaping network (Pulse Shaping Network), the output end of the second digital-to-analog converter DAC2 is connected to the low pass filter, the analog signal Analog Singal output by the second digital-to-analog converter DAC2 is input into the low pass filter, the low pass filter is connected to the multiplier, the pulse train generator is also connected to the multiplier, the output end of the multiplier is connected to the pulse shaping network, and the output end of the pulse shaping network outputs a PAM signal; the specific waveform diagram of the PAM signal is as shown Fig. 22 shown.

[0076] It should be noted that, in the present embodiment, both the pulse width modulation unit and the pulse amplitude modulation unit are provided with a digital-to-analog converter. In other embodiments, the two digital-to-analog converters in the pulse width modulation unit and the pulse amplitude modulation unit may be externalized, that is, the pulse width modulation unit only includes a comparator, and the pulse amplitude modulation unit only includes a pulse amplitude modulator; or only one external digital-to-analog converter may be provided, the input of the external digital-to-analog converter is connected to the grayscale voltage conversion submodule, and the output of the digital-to-analog converter is respectively connected to the pulse width modulation unit and the pulse amplitude modulation unit.

[0077] In one embodiment, if Figure 6 As shown, the output voltage generating submodule 13 further includes: an output signal selecting unit 133 connected to the pulse width modulation unit 131 and the pulse amplitude modulation unit 132, and configured to determine the analog output type of the second analog data signal according to the received output control signal Output_select.

[0078] Specifically, the correspondence between the output control signal Output_select and the analog output type of the second analog data signal can be pre-set, and then the analog output type of the second analog data signal is determined by the set correspondence. 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 correspondence 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, it can be reasonably set as needed.

[0079] Specifically, the output signal selection unit 133 may include a second multiplexer switch MUX2 and a third multiplexer switch MUX3, such as MUX2 is a single-input and two-output multiplexer switch, and MUX3 is a two-input and single-output multiplexer switch. The input end of the second multiplexer switch is connected to the grayscale voltage conversion submodule 12, and the two output ends of the second multiplexer switch are respectively connected to the pulse width modulation unit 131 and the pulse amplitude modulation unit 132. The two input ends of the third multiplexer switch are respectively connected to the pulse width modulation unit 131 and the pulse amplitude modulation unit 132, and the output end of the third multiplexer switch outputs the second analog data signal. Of course, in other embodiments, the output signal selection unit 133 may also be composed of a plurality of single-input and single-output switches, and this embodiment is only schematically illustrated and is not limited thereto, and may be reasonably set according to actual needs.

[0080] The LED driver chip determines the appropriate output mode through the output signal selection unit, realizes multiple AM ​​controls on the LED, and improves the control flexibility and accuracy.

[0081] In one embodiment, if Figure 7 As shown, the LED driver chip further includes: a first switch module 2 connected to the scan signal and logic control module 1, and used to generate an LED control signal according to the scan signal and the second analog data signal.

[0082] Specifically, Fig.10As shown, the first switch module 2 can be an N-type TFT switch tube 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 is obtained according to the scan signal and the second analog data signal, and the control signal is also the signal output by the source of T1. In other embodiments, the first switch module can also be a P-type TFT switch tube, or other types of switch tubes, such as MOS tubes, etc. This embodiment is only for schematic illustration and is not limited thereto. It can be reasonably set according to needs.

[0083] In one embodiment, if Figure 8 As shown, the LED driver chip further includes: a second switch module 3 connected to the first switch module 2 and the LED, and used to control the on and off of the LED according to the LED control signal.

[0084] Specifically, Fig.10 As shown, the second switch module 3 can be an N-type TFT switch tube 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 line. The LED is turned on and off according to the LED control signal. In other embodiments, the second switch module can also be a P-type TFT switch tube, or other types of switch tubes, such as MOS tubes, etc. This embodiment is only for schematic illustration and is not limited thereto. It can be reasonably set according to needs.

[0085] In one embodiment, if Fig. 9 As shown, the LED driver chip further includes: a charge storage module 4 connected to the first switch module 2 and used for storing LED control signals.

[0086] Specifically, Fig.10 As shown, the charge storage module 4 can be a storage capacitor Cst, a first end of the storage capacitor Cst is connected to the output end of the first switch module 2, and a first end of the storage capacitor Cst is connected to the ground line. The charge storage module in this embodiment is only schematically described, and this is not taken as an example. In other embodiments, the charge storage module can be reasonably set as needed.

[0087] It should be noted that since N-type switching tubes and P-type switching tubes have different characteristics, their connection methods with LEDs are also different. The connection relationship needs to be reasonably determined according to the type of switching tube, and the connection of the LED and the charge storage module also need to be adaptively adjusted.

[0088] The working process of the LED driver chip is described in detail below. Figure 11-14 shown.

[0089] like Fig.11As shown, the input first analog data signal is an analog voltage (Analog voltage), and the second analog data signal obtained after conversion by the LED driver chip is a PAM signal. The voltage value (Analog voltage) of the first analog data signal is variable, so it can be subjected to voltage detection. In the first cycle 0 to 1H, the voltage value of the input first analog data signal is 1.5V, and after passing through the grayscale information encoding submodule, a digital grayscale signal is generated, and the grayscale value is 511; after passing through the grayscale voltage conversion submodule, the value of the digital output signal generated is 6; finally, after passing through the output voltage generation submodule, the voltage value of the second analog data signal output is 6V. In the second cycle 1H to 2H, the voltage value of the input first analog data signal is 3V, and after passing through the grayscale information encoding submodule, a digital grayscale signal is generated, and the grayscale value is 1023; after passing through the grayscale voltage conversion submodule, the value of the digital output signal generated is 8; finally, after passing through the output voltage generation submodule, the voltage value of the second analog data signal output is 8V. In other embodiments, the output second analog data signal can also be a PWM signal, and the working process is similar to it, which will not be repeated here.

[0090] like Fig.12 As shown, the duty cycle of the input first analog data signal varies in different cycles, so the duty cycle detection can be performed on it. In the first cycle 0~1H, the duty cycle of the input first analog data signal is 50%, and after passing through the grayscale information encoding submodule, a digital grayscale signal is generated, and the grayscale value is 511; the value of the digital output signal generated after conversion by the grayscale voltage conversion submodule is 6; finally, the voltage value of the second analog data signal output by the output voltage generation submodule is 6V. In the second cycle 1H~2H, the duty cycle of the input first analog data signal is 80%, and after passing through the grayscale information encoding submodule, a digital grayscale signal is generated, and the grayscale value is 1023; the value of the digital output signal generated after conversion by the grayscale voltage conversion submodule is 8; finally, the voltage value of the second analog data signal output by the output voltage generation submodule is 8V. In other embodiments, the output second analog data signal can also be a PWM signal, and the working process is similar to it, which will not be repeated here.

[0091] like Fig.13As shown, the frequency of the input first analog data signal changes in different cycles, so it can be frequency detected. In the first cycle 0~1H, the frequency of the input first analog data signal is 1MHz, and after passing through the grayscale information encoding submodule, a digital grayscale signal is generated, and the grayscale value is 511; after being converted by the grayscale voltage conversion submodule, the value of the digital output signal generated is 6; finally, the voltage value of the second analog data signal output by the output voltage generation submodule is 6V. In the second cycle 1H~2H, the frequency of the input first analog data signal is 2MHz, and after passing through the grayscale information encoding submodule, a digital grayscale signal is generated, and the grayscale value is 1023; after being converted by the grayscale voltage conversion submodule, the value of the digital output signal generated is 8; finally, the voltage value of the second analog data signal output by the output voltage generation submodule is 8V. Through the above process, PAM control of LED can be achieved.

[0092] like Fig.14 As shown, the frequency of the input first analog data signal changes in different cycles, so it can be frequency detected. In the first cycle 0~1H, the frequency of the input first analog data signal is 1MHz, and after passing through the grayscale information encoding submodule, a digital grayscale signal is generated, and the grayscale value is 511; the value of the digital output signal generated after conversion by the grayscale voltage conversion submodule is 60; finally, the duty cycle of the second analog data signal output by the output voltage generation submodule is 60%. In the second cycle 1H~2H, the frequency of the input first analog data signal is 2MHz, and after passing through the grayscale information encoding submodule, a digital grayscale signal is generated, and the grayscale value is 1023; the value of the digital output signal generated after conversion by the grayscale voltage conversion submodule is 80; finally, the duty cycle of the second analog data signal output by the output voltage generation submodule is 80%. Through the above process, PWM control of LED can be achieved.

[0093] The embodiment of the present invention further provides a backlight unit, such as Fig.15 As shown, it includes: a back panel 151; a light source, which is arranged on the back panel 151 and includes a plurality of LEDs 152 arranged in an array; and a plurality of LED driver chips 153 as described in any of the above embodiments, the LED driver chips 153 are arranged on the back panel 151 and correspond one-to-one to the plurality of LEDs 152.

[0094] It should be noted that Fig.15 The LED 152 in the figure is composed of multiple mini LEDs connected in series. In this case, the multiple mini LEDs are regarded as one LED 152.

[0095] In one embodiment, the backplane can be a printed circuit board (PCB board) or a thin film transistor backplane, such as an LTPS backplane, an α-Si backplane, etc. This is only described schematically in this embodiment and is not limited to this. In other embodiments, the backplane can also adopt other types of backplanes in the prior art, such as a glass backplane, etc.

[0096] In one embodiment, the LED may be a mini LED or a micro LED, which is only described schematically in this embodiment and is not limited thereto.

[0097] In one embodiment, when the LED driver chip does not include the first switch module, the first switch module may be a discrete device; the first switch module may also be directly made on the thin film transistor backplane, specifically, may be composed of stacked film layers.

[0098] In one embodiment, when the LED driver 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 fabricated on the thin film transistor backplane, specifically, may be formed of stacked film layers.

[0099] In one embodiment, when the LED driver chip does not include a charge storage module, the charge storage module may be a discrete device or may be directly made on the backplane. Specifically, the charge storage module may be formed by a film layer in a PCB board or by a film layer in a thin film transistor backplane.

[0100] The backlight unit adopts the above LED driving chip, realizes the flexible selection of the AM driving mode of the LED, can select the appropriate control mode according to the actual working conditions of the LED, and improves the accuracy and flexibility of the LED control.

[0101] The embodiment of the present invention further provides a display panel, comprising: a backlight unit as described in any one of the embodiments. The display panel adopts the above-mentioned LED driver chip, realizes the flexible selection of the AM drive mode of the LED, and can select a suitable control mode according to the actual working conditions of the LED, thereby improving the accuracy and flexibility of the LED control.

[0102] In one embodiment, the display panel may be an LCD display panel, or may be other types of display panels, for example, any display panel requiring a backlight.

[0103] The embodiment of the present invention further provides a display device, comprising the display panel as described above. The display device adopts the above LED driver chip, realizes flexible selection of the AM drive mode of the LED, can select a suitable control mode according to the actual working condition of the LED, and improves the accuracy and flexibility of the LED control.

[0104] The above-mentioned display device can be a mobile phone, a tablet, a television, a monitor, a PDA, an iPod, a digital camera, a navigator, a car display screen, or other product or component with a display function.

[0105] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. An LED driver chip, characterized in that: The LED driver chip is connected to an LED and is used to control the LED. The LED driver chip includes: A logic control module, configured to receive a first analog data signal common to a row or a column at the location of the LED and convert the first analog data signal into a second analog data signal for individually controlling the LED; The logic control module comprises: A grayscale information encoding submodule, used for encoding the first analog data signal to generate a digital grayscale signal; A grayscale voltage conversion submodule, connected to the grayscale information encoding submodule, for generating a digital output signal according to the digital grayscale signal; an output voltage generating submodule, connected to the grayscale voltage converting submodule, and configured to generate a second analog data signal according to the digital output signal; Wherein, the grayscale information encoding submodule includes: a duty cycle detection unit, configured to detect duty cycle information of the first analog data signal, and encode the duty cycle information to generate a first digital output type of the digital grayscale signal; A frequency detection unit, used for detecting frequency information of the first analog data signal, and encoding the frequency information to generate a second digital output type of the digital grayscale signal; The voltage detection unit is used to detect the voltage information of the first analog data signal, and encode the voltage information to generate a third digital output type of the digital grayscale signal.

2. The LED driver chip according to claim 1, characterized in that: The grayscale information encoding submodule also includes: An input signal selection unit is connected to the duty cycle detection unit, the frequency detection unit and the voltage detection unit, and is used to determine the digital output type of the digital grayscale signal according to a received input control signal.

3. The LED driver chip according to claim 1, characterized in that: The grayscale voltage conversion submodule is further used to determine the conversion relationship between the digital grayscale signal and the digital output signal according to the received conversion relationship selection signal.

4. The LED driver chip according to claim 1, characterized in that: The output voltage generation submodule comprises: a pulse width modulation unit connected to the grayscale voltage conversion submodule, and configured to generate a first analog output type of a second analog data signal according to the digital output signal; The pulse amplitude modulation unit is connected to the grayscale voltage conversion submodule and is used to generate a second analog output type of a second analog data signal according to the digital output signal.

5. The LED driver chip according to claim 4, characterized in that: The output voltage generation submodule also includes: An output signal selection unit is connected to the pulse width modulation unit and the pulse amplitude modulation unit, and is used to determine the analog output type of the second analog data signal according to a received output control signal.

6. The LED driver chip according to any one of claims 1 to 5, characterized in that: The LED driver chip also includes: A first switch module, connected to the scan signal and the logic control module, and configured to generate an LED control signal according to the scan signal and the second analog data signal; The LED driver chip further includes: a second switch module connected to the first switch module and the LED, and configured to control the on and off of the LED according to the LED control signal; The LED driver chip also includes: A charge storage module is connected to the first switch module and is used to store the LED control signal.

7. A backlight unit, characterized in that: include: Back panel; A light source, disposed on the back panel, comprising a plurality of LEDs arranged in an array; The plurality of LED driver chips as described in any one of claims 1 to 6 are arranged on the backplane and correspond one-to-one to the plurality of LEDs.

8. A display panel, characterized in that: Comprising the backlight unit as claimed in claim 7.

9. A display device, characterized in that: Comprising the display panel as claimed in claim 8.

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