Display driving element and display driving device using same

Abstract

The present disclosure is applicable to the technical field related to display devices, and relates to, for example, a display driving element and a display driving device using same. The display driving device according to an embodiment of the present disclosure may comprise: a plurality of driving elements including a channel to which one end of at least one light emitting element array is connected, wherein the driving elements comprise an SPI interface having an input terminal and an output terminal, and output a detection signal obtained by detecting a headroom voltage for driving the light emitting element array through the output terminal; and a power supply unit connected to the other end of the light emitting element array to supply power to the driving elements.

Description

Display driving element and display driving device using the same

[0001] The present disclosure is applicable to a technical field related to display devices, and relates, for example, to a display driving element and a display driving device using the same.

[0002] In recent years, display devices with superior characteristics, such as thinness and flexibility, have been developed in the field of display technology. Currently, the major commercially available displays are represented by LCD (Liquid Crystal Display) and OLED (Organic Light Emitting Diode).

[0003] Meanwhile, a light-emitting diode (LED) is a semiconductor light-emitting device that is well known for converting electric current into light. Starting with the commercialization of a red LED using GaAsP compound semiconductors in 1962, it has been used as a light source for display images in electronic devices, including information and communication devices, along with green LEDs of the GaP:N series.

[0004] Recently, these light-emitting diodes (LEDs) have been gradually miniaturized and manufactured into millimeter- or micrometer-sized LEDs, which are used as pixels or flat lighting in display devices.

[0005] In order for LEDs to be used as flat lighting, a driving element (driving IC) that drives multiple LED strings and a power supply that supplies power to the LEDs can be used.

[0006] These driving elements are combined with a certain number of LED strings forming a channel, and a method is required to detect the driving status of the LEDs and feed back the driving status to the power supply.

[0007] The technical problem to be solved by the present disclosure is to provide a display driving element having an efficient configuration for detecting the driving state of a light-emitting element and feeding back the driving state to a power supply, and a display driving device using the same.

[0008] Meanwhile, it is intended to provide a display driving element and a display driving device using the same that can detect the driving status of a light-emitting element more quickly by eliminating frame latency and feed back the driving status to a power supply.

[0009] Meanwhile, it is an object to provide a display driving element capable of reducing the number of connection lines and connection pins of a driving element and a display driving device using the same.

[0010] A display driving device according to one embodiment of the present disclosure comprises: a plurality of driving elements including a channel to which one end of at least one light-emitting element array is connected; and a power supply unit connected to the other end of the light-emitting element array to supply power, wherein the driving element comprises: a channel to which one end of the at least one light-emitting element array is connected; an SPI interface having an input end and an output end; a detection unit connected to the channel to detect a headroom voltage for driving the light-emitting element array and output the detection signal; and a feedback detection unit receiving the detection signal from the detection unit and outputting a feedback signal, wherein the detection signal detecting the headroom voltage for driving the light-emitting element array can be output through an output end of the SPI interface.

[0011] A display driving device according to one embodiment of the present disclosure includes: a channel to which one end of at least one light-emitting element array is connected; an SPI interface having an input end and an output end; a detection unit connected to the channel to detect a headroom voltage for driving the light-emitting element array and output the detection signal; and a feedback detection unit receiving the detection signal from the detection unit and outputting a feedback signal, wherein the detection signal detecting the headroom voltage for driving the light-emitting element array can be output through an output end of the SPI interface.

[0012] A backlight driving device according to one embodiment of the present disclosure may include: at least one light-emitting element array including a plurality of rows of light-emitting elements; a plurality of driving elements including a channel to which one end of the light-emitting element array is connected, wherein the driving elements include an SPI interface having an input end and an output end, and output a detection signal detecting a headroom voltage for driving the light-emitting element array through the output end; and a power supply unit connected to the other end of the light-emitting element array to supply power to the power supply unit.

[0013] According to an embodiment of the present disclosure, an efficient configuration can be provided for detecting the driving state of a light-emitting element and feeding back the driving state to a power supply.

[0014] Meanwhile, by eliminating frame latency, the operating status of the light-emitting element can be detected more quickly and this operating status can be fed back to the power supply.

[0015] Meanwhile, the number of connection lines and connection pins of the driving element can be reduced, thereby enabling the design of a circuit board (PCB) for a single-layer light-emitting element array.

[0016] Meanwhile, the pins of the display driver device may be freed up. Additionally, external pull-up resistors may be eliminated.

[0017] Meanwhile, since a time-division control method can be utilized, real-time monitoring and control of the driving voltage accordingly can be possible.

[0018] Furthermore, according to another embodiment of the present invention, there are additional technical effects not mentioned herein. Those skilled in the art will understand the full scope of the specification and drawings.

[0019] FIG. 1 is a circuit diagram showing a display driving device according to a first embodiment of the present disclosure.

[0020] FIG. 2 is a signal diagram showing the operation of a display driving device according to the first embodiment of the present disclosure.

[0021] FIG. 3 is a block diagram showing the physical connection state of a display driving device according to the first embodiment of the present disclosure.

[0022] Fig. 4 is a circuit diagram showing a display driving device according to a second embodiment of the present disclosure.

[0023] FIG. 5 is a timing diagram showing the operation of a display driving device according to a second embodiment of the present disclosure.

[0024] FIG. 6 is a signal diagram showing the operation of a display driving device according to a second embodiment of the present disclosure.

[0025] Fig. 7 is a circuit diagram showing a display driving device according to a third embodiment of the present disclosure.

[0026] Fig. 8 is a timing diagram showing the operation of a display driving device according to a third embodiment of the present disclosure.

[0027] Figure 9 is a block diagram showing a data transmission process according to embodiments of the present disclosure.

[0028] FIG. 10 is a block diagram showing the physical connection status of a display driving device according to embodiments of the present disclosure.

[0029] Fig. 11 is a flowchart showing the operation process of a display driving device according to embodiments of the present disclosure.

[0030] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or similar components will be given the same reference numbers, and redundant descriptions thereof will be omitted. The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably only for the convenience of writing the specification, and do not in themselves have distinct meanings or roles. In addition, when describing the embodiments disclosed in this specification, if it is determined that a specific description of a related known technology may obscure the gist of the embodiments disclosed in this specification, a detailed description thereof will be omitted. In addition, it should be noted that the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in this specification, and should not be construed as limiting the technical ideas disclosed in this specification by the attached drawings.

[0031] Furthermore, for the convenience of explanation, each drawing is described, but it is also within the scope of the present invention for a person skilled in the art to implement another embodiment by combining at least two drawings.

[0032] Additionally, when an element such as a layer, region or substrate is referred to as existing "on" another element, it will be understood that this may be directly on the other element, or that there may be intermediate elements in between.

[0033] The display device described in this specification is a concept that includes all display devices that display information as a unit pixel or a set of unit pixels. Therefore, it can be applied not only to finished products but also to components. For example, a panel corresponding to a component of a digital TV is also a display device in this specification. Finished products may include mobile phones, smart phones, laptop computers, digital broadcasting terminals, personal digital assistants (PDAs), portable multimedia players (PMPs), navigation systems, slate PCs, tablet PCs, Ultrabooks, digital TVs, desktop computers, etc.

[0034] However, it will be readily apparent to those skilled in the art that the configuration according to the embodiments described herein may be applied to any device capable of displaying, even if it is a new product type developed in the future.

[0035] In addition, the light-emitting element mentioned in the specification includes LED, mini LED, micro LED, etc., and may be used interchangeably.

[0036] FIG. 1 is a circuit diagram showing a display driving device according to a first embodiment of the present disclosure.

[0037] Referring to FIG. 1, a display driving device (1) according to a first embodiment of the present disclosure may include a plurality of driving elements (driving ICs, driving chips; 10) connected to light-emitting element arrays (D1 to D8), a power supply unit (30) that supplies power to the light-emitting element arrays (D1 to D8), and a control unit (20) connected between the driving elements (10) and the power supply unit (30).

[0038] This display driving device (1) is a device that drives a plurality of light-emitting element arrays (D1 to D8), and may correspond to, for example, a flat lighting device (1) or a backlight unit (BLU). Hereinafter, the terms display driving device and flat lighting device are used interchangeably in the description.

[0039] Meanwhile, a plurality of driving elements (driving ICs; 10) connected to the light-emitting element array (D1 to D8) may be referred to as a display driving element (10). Hereinafter, the terms driving chip, driving element, and display driving element are used interchangeably in the description.

[0040] The driving element (10) may include channels (CH1 to CH8) to which one end of at least one light-emitting element array (D1 to D8) is connected. As an exemplary embodiment, the driving element (10) may be provided with eight channels (CH1 to CH8).

[0041] Each channel (CH1 to CH8) may be connected to an array of light-emitting elements (D1 to D8). One array of light-emitting elements (e.g., D1) may include a string of light-emitting elements in which a plurality of light-emitting elements are connected. For example, one channel (e.g., CH1) may be connected to one side of an array of light-emitting elements (D1) including a plurality of light-emitting elements connected in series with each other.

[0042] The other side of the light emitting element array (D1) can be connected to a power supply (30). Accordingly, the power set in the driving element (10) can be applied to the light emitting element array (D1) by the power supply (30).

[0043] The driving element (10) may include a detection unit (Min Headroom detection; 11) that detects a headroom voltage for driving the light emitting element array (D1 to D8). This detection unit (11) may be connected to each channel (CH1 to CH8).

[0044] The voltage detected by the detection unit (11) can be output through the feedback terminal (FB; 12) via the switch (Pull-Down Switch; 13). Accordingly, when the driving element (10) is implemented as an IC, the driving element (10) includes a feedback pin (terminal; FB; 12), so that the headroom voltage detected by the detection unit (11) can be output through the feedback terminal (FB; 12) via the switch (Pull-Down Switch; 13).

[0045] Referring to Fig. 1, a plurality of driving elements (driving ICs; 10) connected to such a light-emitting element array (D1 to D8) can be provided in parallel.

[0046] The feedback terminals (FB; 12) of each of these driving elements (10) can be connected to each other by separate conductors (14). For example, the feedback terminals (12) of each driving IC (10) can be connected to each other by jumper wires.

[0047] A pull-up resistor (Rp) may be connected to the feedback terminal (12) of the driving element (10) located at the rear end. For example, the pull-up resistor (Rp) may be provided so that the input value of the feedback terminal (12) is accurately input to the detection terminal (21) of the control unit (MCU; 20).

[0048] A feedback signal according to the headroom voltage generated from the light-emitting element array (D1 to D8) connected to each driving element (10) is accumulated and input to the detection terminal (21) of the control unit (20), and the feedback signal input to the detection terminal (21) can be converted into an analog signal by a DA converter (digital to analogue converter; DAC; 22) and transmitted to the power supply unit (30).

[0049] In the power supply unit (30), a boost converter (31) operates based on a feedback signal converted into an analog signal, and the boosted voltage is transmitted to each light emitting element array (D1 to D8).

[0050] By this configuration, a preset output voltage level is detected for each channel in each driving element (10), and when the headroom voltage (min headroom voltage) is detected for even one channel, a pull down signal of the driving element (10) is transmitted to the control unit (MCU; 20). At this time, the transmitted signal is transmitted to the power supply unit (30) through the detection terminal (21) and the DA converter (DAC; 22). In the power supply unit (30), a control signal is transmitted to a boost converter (31) that generates a light-emitting element driving voltage (VLED), thereby ultimately increasing the light-emitting element driving voltage (VLED).

[0051] By this process, it is possible to detect a decrease in the light-emitting element driving voltage (VLED) due to various factors and boost it so that the light-emitting element array (D1 to D8) can be driven at a constant driving voltage (VLED).

[0052] FIG. 2 is a signal diagram showing the operation of a display driving device according to the first embodiment of the present disclosure.

[0053] In Figure 2, VSYNC is a synchronization signal that distinguishes each frame.

[0054] When the headroom (Min headroom) voltage is detected at the present frame point in time, a feedback signal (FB) is generated through the feedback terminal (FB; 21) and can be input to the DA converter (22) in the control unit (MCU; 20).

[0055] Then, at the next frame point, this feedback action operates so that the voltage of the step-up converter (31) of the power supply (30) increases by the difference (ΔVDAC) of the DAC voltage (VDAC) input to the DA converter (22).

[0056] Accordingly, the light emitting element driving voltage (VLED) is increased again by the amount that has been decreased, so that the light emitting element array (D1 to D8) can be driven with a constant driving voltage (VLED).

[0057] In this way, according to the present embodiment, voltage compensation can be achieved by detecting the headroom (Min headroom) voltage for each frame, generating a pull-down signal through the FB terminal (12), and operating the control unit (20).

[0058] FIG. 3 is a block diagram showing the physical connection state of a display driving device according to the first embodiment of the present disclosure.

[0059] Referring to FIG. 3, each driving element (10) can be connected to each other via an SPI (Serial Peripheral Interface) interface. For example, each driving element (10) can transmit and receive data by performing SPI (Serial Peripheral Interface) communication. For example, local dimming data for driving a flat lighting device (1) or a backlight unit (BLU) can be transmitted via the SPI interface.

[0060] Accordingly, each driving element (10) may include an input terminal (SDI) and an output terminal (SDO) of the SPI interface. Each driving element (10) may be connected to each other through the input terminal (SDI) and the output terminal (SDO) of the SPI interface. For example, the output terminal (SDO) of one driving element (10) may be connected to the input terminal (SDI) of the neighboring driving element (10).

[0061] Referring to FIG. 3, each driving element (10) has a feedback terminal (FB; 12), and these feedback terminals (12) can be connected to each other by a separate conductor (14). These conductors (14) can be connected to a control unit (MCU; 20). For example, the feedback terminals (12) of each driving IC (10) can be connected to each other by a jumper wire.

[0062] As described above, according to this embodiment, a pull-down signal is transmitted to the control unit (20) in units of (video) frames within each driving element (10), so that the driving voltage (VLED) can be controlled in units of frames.

[0063] For this process, a feedback terminal (pin; 12) is required, and a separate external pull-up resistor (Rp) is required. In addition, as described above, many wires (jumper wires; 14) are required for connecting the feedback terminal (12).

[0064] Meanwhile, according to the present embodiment, when the driving element (10) transmits a pull-down signal to the control unit (20), it may be difficult to distinguish whether the feedback (FB) signal is generated due to a decrease in the actual driving voltage (VLED) or a temporary phenomenon caused by coupling. If the feedback (FB) signal is generated due to a temporary phenomenon, a problem may occur in the circuit if the driving voltage (VLED) increases due to the operation of the circuit.

[0065] Fig. 4 is a circuit diagram showing a display driving device according to a second embodiment of the present disclosure.

[0066] Referring to FIG. 4, a display driving device (100) according to a second embodiment of the present disclosure may include a plurality of driving elements (driving chips, driving ICs; 110) connected to light-emitting element arrays (D1 to D8), a power supply unit (130) that supplies power to the light-emitting element arrays (D1 to D8), and a control unit (120) connected between the driving elements (110) and the power supply unit (130).

[0067] This display driving device (100) is a device that drives a plurality of light-emitting element arrays (D1 to D8), and may correspond to, for example, a flat lighting device (100) or a backlight unit (BLU). Hereinafter, the terms display driving device and flat lighting device are used interchangeably in the description.

[0068] Meanwhile, a plurality of driving elements (driving chips, driving ICs; 110) connected to the light-emitting element arrays (D1 to D8) may be referred to as display driving elements (110). Hereinafter, the terms driving element, driving chip, and display driving element are used interchangeably in the description.

[0069] The driving element (110) may include channels (CH1 to CH8) to which one end of at least one light-emitting element array (D1 to D8) is connected. As an exemplary embodiment, the driving element (110) may be provided with eight channels (CH1 to CH8).

[0070] Each channel (CH1 to CH8) may be connected to an array of light-emitting elements (D1 to D8). One array of light-emitting elements (e.g., D1) may include a string of light-emitting elements in which a plurality of light-emitting elements are connected. For example, one channel (e.g., CH1) may be connected to one side of an array of light-emitting elements (D1) including a plurality of light-emitting elements connected in series with each other.

[0071] The other side of the light emitting element array (D1) can be connected to a power supply (130). Accordingly, the power set in the driving element (110) can be applied to the light emitting element array (D1) by the power supply (130).

[0072] The driving element (110) may include an SPI interface (111) having an input terminal (SDI; 116) and an output terminal (SDO; 117).

[0073] As described above, each driving element (110) can be connected to each other via a Serial Peripheral Interface (SPI) interface (111). For example, each driving element (110) can transmit and receive data by performing SPI (Serial Peripheral Interface) communication. For example, local dimming data for driving a flat lighting device (100) or a backlight unit (BLU) can be transmitted via the SPI interface (111).

[0074] Accordingly, each driving element (110) can be connected to each other through the input terminal (SDI; 116) and output terminal (SDO; 117) of the SPI interface (111). For example, the output terminal (SDO; 117) of one driving element (110) can be connected to the input terminal (SDI; 116) of the neighboring driving element (110).

[0075] The driving element (110) may include a detection unit (Min Headroom detection; 113) that detects a headroom voltage for driving the light emitting element array (D1 to D8). This detection unit (113) may be connected to each channel (CH1 to CH8).

[0076] According to the present embodiment, a detection signal that detects a headroom voltage for driving the light-emitting element array (D1 to D8) in the detection unit (113) can be output through an output terminal (SDO; 117) of the SPI interface (111). For example, a detection signal that detects a headroom voltage for driving the light-emitting element array (D1 to D8) in the detection unit (113) can be output through an output terminal (SDO; 117) of the SPI interface (111) and input to an input terminal (SDI; 116) of a neighboring driving element (110) or input to a control unit (120).

[0077] Referring to FIG. 4, the driving element (110) may include a detection unit (113) that is connected to channels (CH1 to CH8) to detect a headroom (Min Headroom) voltage for driving the light-emitting element array (D1 to D8) and outputs such a detection signal.

[0078] Additionally, the driving element (110) may include a feedback detection unit (112) that receives a detection signal of the headroom voltage from the detection unit (113) and outputs a feedback signal.

[0079] In this way, data and feedback signals for driving the flat lighting device (100) or backlight unit (BLU) can be transmitted through the SPI interface (111). For example, the driving element (110) may include a multiplexer (MUX; 115) located between the SPI interface (111) and the output terminal (117) for time division between the data signal and feedback signal transmitted through the SPI interface (117).

[0080] Meanwhile, a signal input from the output terminal (117) of the neighboring driving element (110) to the input terminal (116) can be transmitted to the MUX (115) through a logical OR with the feedback signal. For example, a line connected to the input terminal (116) and an output line of the feedback signal can be connected to the MUX (115) through a logical OR operation unit (114).

[0081] For example, when a feedback signal is transmitted from a neighboring driving element (110) through such a connection or a feedback signal is generated from a feedback detection unit (112) in the driving element (110), flag 1 can be transmitted to the MUX (115).

[0082] In this way, when a headroom voltage is detected in a neighboring driving element (110) and a feedback signal is transmitted from the neighboring driving element (110), and when a headroom voltage is detected in the driving element (110) and a feedback signal is generated, if at least one of these two cases applies, a flag 1 can be transmitted to the MUX (115) through the logical operation unit (114).

[0083] Accordingly, if the minimum headroom voltage is detected in any one channel among the channels to which the entire light-emitting element array (D1 to D8) is connected, a feedback signal according to the generation of this headroom voltage is transmitted to the power supply (130) to increase the driving voltage (VLED).

[0084] In this way, the driving element (110) may include a channel (CH1 to CH8) to which one end of at least one light-emitting element array (D1 to D8) is connected, an SPI interface (111) having an input end (116) and an output end (117), a detection unit (113) connected to the channel (CH1 to CH8) to detect a headroom voltage for driving the light-emitting element array (D1 to D8) and output a detection signal, and a feedback detection unit (112) that receives the detection signal from the detection unit (113) and outputs a feedback signal.

[0085] These driving elements (110) can output a detection signal that detects a headroom voltage for driving the light-emitting element array (D1 to D8) to a neighboring driving element (110) or a control unit (120) through the output terminal (117) of the SPI interface (111).

[0086] Therefore, according to the present embodiment, a separate feedback terminal to which a detection signal or feedback signal is transmitted according to detection of the headroom voltage may not be required.

[0087] Referring to Fig. 4, a plurality of driving elements (driving ICs; 110) connected to such a light-emitting element array (D1 to D8) may be connected in parallel with each other. Accordingly, a separate wire or jumper wire connecting each driving element (110) may not be required. In addition, a separate pull-up resistor may not be required.

[0088] A feedback signal according to the headroom voltage generated from the light-emitting element array (D1 to D8) connected to each driving element (110) can be converted into an analog signal by the DA converter (121) of the control unit (120) and transmitted to the power supply unit (130).

[0089] In the power supply unit (130), a boost converter (131) operates based on a feedback signal converted into an analog signal, so that the boosted voltage can be transmitted to each light emitting element array (D1 to D8).

[0090] By this configuration, a preset output voltage level for each channel is detected in each driving element (110), and if the headroom voltage (min headroom voltage) is detected in even one channel, a feedback signal of the driving element (110) can be transmitted to the control unit (MCU; 120) through communication using the SPI interface (111).

[0091] At this time, the transmitted signal can be transmitted to the power supply unit (130) through the DA converter (121) of the control unit (120). In the power supply unit (130), the control signal is transmitted to the boost converter (131) that generates the light-emitting element driving voltage (VLED), thereby ultimately increasing the light-emitting element driving voltage (VLED).

[0092] By this process, it is possible to detect a decrease in the light-emitting element driving voltage (VLED) due to various factors and boost it so that the light-emitting element array (D1 to D8) can be driven at a constant driving voltage (VLED).

[0093] As described above, the display driving device (100) includes a plurality of driving elements (110) including channels (CH1 to CH8) to which one end of at least one light-emitting element array (D1 to D8) is connected, and the driving elements (110) include an SPI interface (111) having an input terminal (116) and an output terminal (117), and a detection signal detecting a headroom voltage for driving the light-emitting element array (D1 to D8) can be output through the output terminal (117).

[0094] The display driving device (100) may include a power supply unit (130) that is connected to the other end of the light-emitting element array (D1 to D8) to supply power, and a control unit (120) that is positioned between the driving element (110) and the power supply unit (130) and controls the power supply unit (130) by inputting a detection signal.

[0095] As described above, the design of a circuit board (PCB) for a single-layer light-emitting element array can be made possible because no pins for feedback are required for the driving element (110). In this way, the pins of the driving element (110) can be made more flexible. In addition, an external pull-up resistor can be eliminated.

[0096] Meanwhile, since these feedback signals can be transmitted within (video) frames, frame latency can be eliminated.

[0097] In addition, a time-division control method can be utilized through the output terminal (SDO; 117), so that real-time monitoring and control of the driving voltage (VLED) can be achieved accordingly.

[0098] FIG. 5 is a timing diagram showing an example of the operation of a display driving device according to embodiments of the present disclosure.

[0099] In Figure 5, VSYNC is a synchronization signal that distinguishes each (video) frame.

[0100] Referring to FIG. 5, the time period (SPI time period) in which data (DATA) transmitted via SPI communication is transmitted may be located within a frame. This SPI time period may be shorter than the duration of one frame. Accordingly, the feedback signal may be transmitted at a time outside of the SPI time period. For example, the feedback signal may be transmitted to the power supply (130) during the pause period of the data (DATA).

[0101] In this way, the feedback signal and the data signal can be transmitted in a time-division manner through the SPI interface (111) for SPI communication. For example, when a data signal is transmitted through the SPI interface (111), the feedback signal can be transmitted through the SPI interface (111) with a time difference from the data signal.

[0102] For example, the feedback detection time (FB sensing time) may be longer than the SPI time period. For example, the feedback detection time may be located between frame synchronization signals, and this feedback detection time may be longer than the SPI time period.

[0103] For example, when a feedback signal is detected in the feedback detection unit (112) and a flag is output as 1 (FB_EN = '1'), this flag may occur after the SPI time domain. Flag generation according to this feedback signal may occur simultaneously for all driving elements (110) (FB flag simultaneously all chips).

[0104] As mentioned above, time division between these data signals and feedback signals can be achieved by a multiplexer (MUX; 115). After a data signal, such as local dimming data, is received, the signal can be processed by the MUX (115) during an idle period.

[0105] For example, when the headroom voltage is detected in the detection unit (113) and a detection signal is output, a feedback signal may be output from the feedback detection unit (112). This feedback signal (FB Flag) may be transmitted to the MUX (115) through the logical operation unit (114).

[0106] In addition, a signal (FB_EN) notifying that a feedback signal has been generated from the feedback detection unit (112) may be generated and transmitted to the MUX (115). The MUX (115) may recognize the signal (FB_EN) notifying that such a feedback signal has been generated as 1.

[0107] In this way, the MUX (115) can be controlled by the FB_EN signal. That is, the FB_EN signal can be a control signal of the Mux (115). In this way, the data signal and the feedback signal can be time-divided and transmitted through the MUX (115). For example, when the control signal of the MUX (115) is 1 (FB_EN signal generation), the MUX (115) can recognize that a feedback signal is input. Accordingly, the feedback signal can be transmitted to the output terminal (117) through the MUX (115). On the other hand, when the control signal of the MUX (115) is 0, the MUX (115) recognizes this as a data signal, and the data signal can be processed and transmitted to the output terminal (117).

[0108] The signal transmitted to the output terminal (117) in this way can be transmitted through the input terminal (116) of the neighboring driving element (110). The same operation as described above can be performed in the neighboring driving element (110). Finally, this output signal can be applied to the power supply (130).

[0109] Accordingly, the driving voltage (VLED) may increase in the next frame. In this way, compensation of the driving voltage (VLED) may be achieved.

[0110] An example of the operation of such a display driving device can be equally applied to the third embodiment of the present disclosure below.

[0111] FIG. 6 is a signal diagram showing the operation of a display driving device according to embodiments of the present disclosure.

[0112] In Figure 6, VSYNC is a synchronization signal that distinguishes each frame.

[0113] As described above, the feedback detection time (FB sensing time) can be longer than the SPI time. For example, the feedback detection time can be located within each frame.

[0114] When a flag (FB flag) is generated (high; 'H') upon detection of a feedback signal, a feedback signal may be generated (FB_EN) and transmitted after the SPI time domain. Accordingly, the signal may be converted into an analog signal by the DA converter (121) of the control unit (120) and transmitted to the power supply unit (130). In the power supply unit (130), a boost converter (131) operates based on the feedback signal converted into the analog signal, so that the boosted driving voltage (VLED) may be transmitted to each light emitting element array (D1 to D8).

[0115] Figure 6 illustrates an example where such a feedback signal occurs every frame. Accordingly, the output signal of the DA converter (121) can be increased stepwise by ΔVDAC. This allows the driving voltage (VLED) to increase, thereby achieving voltage compensation.

[0116] This voltage compensation operation can be stopped when a set threshold is reached. For example, the flag (FB flag) can be switched to 'L' and the DA converter (121) can be reset.

[0117] Accordingly, the light emitting element driving voltage (VLED) is increased again by the amount that has been decreased, so that the light emitting element array (D1 to D8) can be driven with a constant driving voltage (VLED).

[0118] In this way, according to the present embodiment, voltage compensation can be performed by detecting the headroom (Min headroom) voltage within each frame.

[0119] An example of the operation of such a display driving device can be equally applied to the third embodiment of the present disclosure below.

[0120] Fig. 7 is a circuit diagram showing a display driving device according to a third embodiment of the present disclosure.

[0121] Referring to FIG. 7, a display driving device (101) according to a third embodiment of the present disclosure may include a plurality of driving elements (driving ICs; 110) connected to light-emitting element arrays (D1 to D8), a power supply unit (130) that supplies power to the light-emitting element arrays (D1 to D8), and a control unit (120) connected between the driving elements (110a) and the power supply unit (130).

[0122] This display driving device (101) is a device that drives a plurality of light-emitting element arrays (D1 to D8), and may correspond to, for example, a flat lighting device (101) or a backlight unit (BLU). Hereinafter, the terms display driving device and flat lighting device are used interchangeably in the description.

[0123] Meanwhile, a plurality of driving elements (driving ICs; 110a) connected to the light-emitting element arrays (D1 to D8) may be referred to as display driving elements (110a). Hereinafter, the terms driving element, driving chip, and display driving element are used interchangeably in the description.

[0124] Additionally, the description of the second embodiment described above can be applied equally to parts not described herein. Therefore, any duplicate description will be omitted.

[0125] The driving element (110a) may include channels (CH1 to CH8) to which one end of at least one light-emitting element array (D1 to D8) is connected. As an exemplary embodiment, the driving element (110a) may be provided with eight channels (CH1 to CH8).

[0126] Each channel (CH1 to CH8) may be connected to an array of light-emitting elements (D1 to D8). One array of light-emitting elements (e.g., D1) may include a string of light-emitting elements in which a plurality of light-emitting elements are connected. For example, one channel (e.g., CH1) may be connected to one side of an array of light-emitting elements (D1) including a plurality of light-emitting elements connected in series with each other.

[0127] The other side of the light emitting element array (D1) can be connected to a power supply (130). Accordingly, the power set in the driving element (110a) can be applied to the light emitting element array (D1) by the power supply (130).

[0128] The driving element (110a) may include an SPI interface (111) having an input terminal (SDI; 116) and an output terminal (SDO; 117).

[0129] As described above, each driving element (110a) can be connected to each other through an SPI (Serial Peripheral Interface) interface (111). For example, each driving element (110a) can be connected to each other through an input terminal (SDI; 116) and an output terminal (SDO; 117) of the SPI interface (111). For example, an output terminal (SDO; 117) of one driving element (110a) can be connected to an input terminal (SDI; 116) of a neighboring driving element (110a).

[0130] The driving element (110a) may include a detection unit (Min Headroom detection; 113) that detects a headroom voltage for driving the light emitting element array (D1 to D8). This detection unit (113) may be connected to each channel (CH1 to CH8).

[0131] According to this embodiment, a detection signal detecting a headroom voltage for driving a light-emitting element array (D1 to D8) in a detection unit (113a) can be output through an output terminal (SDO; 117) of an SPI interface (111).

[0132] Referring to FIG. 7, the driving element (110a) may include a detection unit (113) that is connected to the channels (CH1 to CH8) to detect a headroom (Min Headroom) voltage for driving the light-emitting element array (D1 to D8) and outputs such a detection signal.

[0133] Additionally, the driving element (110a) may include a feedback detection unit (112) that receives a detection signal of the headroom voltage from the detection unit (113) and outputs a feedback signal.

[0134] In this way, data and feedback signals for driving the flat lighting device (101) or the backlight unit (BLU) can be transmitted through the SPI interface (111). For example, the driving element (110a) may include a multiplexer (MUX) 115 for time division between the data signal and the feedback signal transmitted through the SPI interface (117) and positioned between the SPI interface (111) and the output terminal (117). Hereinafter, the multiplexer (115) for time division between the data signal and the feedback signal transmitted through the SPI interface (117) is referred to as a first multiplexer (first MUX; 115).

[0135] Meanwhile, the driving element (110a) may further include a second multiplexer (second MUX; 119) for time division between the output signal of the first MUX (115) and the detection signal.

[0136] A DA converter (118) may be included between the feedback detection unit (112) and the second MUX (119). In this way, a signal detected by the feedback detection unit (112) may be transmitted to the second MUX (119) through the DA converter (118).

[0137] In addition, when a feedback signal is transmitted from a neighboring driving element (110a) or a feedback signal is generated from a feedback detection unit (112) in the driving element (110a), flag 1 can be transmitted to the first MUX (115).

[0138] In this way, according to the present embodiment, a DA converter (118) may be provided between the feedback detection unit (112) of the driving element (110a) and the second MUX (119). Therefore, a control unit for such operation may not be required. For example, the driving element (110a) may be directly connected to the power supply unit (130).

[0139] For example, a signal detected by a feedback detection unit (112) is converted into an analog voltage through a DA converter (118), and this analog voltage can be connected to a step-up converter (131) of a power supply unit (130) through a second MUX (119).

[0140] These driving elements (110a) can output a detection signal that detects the headroom voltage for driving the light-emitting element array (D1 to D8) to a neighboring driving element (110a) or a power supply (130) through the output terminal (117) of the SPI interface (111).

[0141] Therefore, according to the present embodiment, a separate feedback terminal to which a detection signal or feedback signal is transmitted according to detection of the headroom voltage may not be required.

[0142] Referring to Fig. 7, a plurality of driving elements (driving ICs; 110a) connected to such a light-emitting element array (D1 to D8) may be provided in parallel. Accordingly, a separate conductor or jumper wire connecting each driving element (110a) may not be required. In addition, a separate pull-up resistor may not be required.

[0143] A feedback signal according to the headroom voltage generated from the light-emitting element array (D1 to D8) connected to each driving element (110a) can be converted into an analog signal by the DA converter (118) of the driving element (110a) and transmitted to the power supply (130).

[0144] In the power supply unit (130), a boost converter (131) operates based on a feedback signal converted into an analog signal, so that the boosted voltage can be transmitted to each light emitting element array (D1 to D8).

[0145] By this configuration, a preset output voltage level for each channel is detected in each driving element (110a), and if the headroom voltage (min headroom voltage) is detected in even one channel, a feedback signal of the driving element (110a) can be transmitted to the power supply unit (130) through communication using the SPI interface (111).

[0146] At this time, the transmitted signal is transmitted as a feedback signal to the boost converter (131) that generates the light-emitting element driving voltage (VLED) in the power supply (130), ultimately increasing the light-emitting element driving voltage (VLED).

[0147] By this process, it is possible to detect a decrease in the light-emitting element driving voltage (VLED) due to various factors and boost it so that the light-emitting element array (D1 to D8) can be driven at a constant driving voltage (VLED).

[0148] As described above, the design of a circuit board (PCB) for a single-layer light-emitting element array can be made possible because a pin for feedback to the driving element (110) is not required. In this way, the pins of the driving element (110a) can be made more flexible. In addition, an external pull-up resistor can be eliminated.

[0149] Meanwhile, since these feedback signals can be transmitted within (video) frames, frame latency can be eliminated.

[0150] In addition, a time-division control method can be utilized through the output terminal (SDO; 117), so that real-time monitoring and control of the driving voltage (VLED) can be achieved accordingly.

[0151] FIG. 8 is a timing diagram showing another example of the operation of a display driving device according to embodiments of the present disclosure.

[0152] In Fig. 8, VSYNC is a synchronization signal that distinguishes each (video) frame.

[0153] Referring to FIG. 8, the time domain (SPI time domain) in which data (DATA) transmitted by SPI communication is transmitted can be located within a frame.

[0154] This SPI time domain may be shorter than the duration of one frame. For example, data (DATA) may be transmitted periodically via the SPI interface (111). For example, this SPI time domain may be divided and positioned within one frame. That is, data (DATA) may be divided and transmitted into multiple parts within one frame. Accordingly, the feedback signal may be transmitted at a time outside the SPI time domain. For example, the feedback signal may be transmitted to the power supply (130) during the pause period of the data (DATA).

[0155] In this way, the feedback signal and the data signal can be transmitted in a time-division manner through the SPI interface (111) for SPI communication. For example, when a data signal is transmitted through the SPI interface (111), the feedback signal can be transmitted through the SPI interface (111) with a time difference from the data signal.

[0156] For example, when a feedback signal is detected in the feedback detection unit (112) and a flag is output as 1 (FB_EN = '1'), this flag may occur between SPI time domains.

[0157] In this way, a feedback signal is generated (FB_EN) between the time periods (SPI time periods) in which data (DATA) is transmitted, so that the headroom voltage can be detected (Min HR detection).

[0158] As mentioned above, time division between these data signals and feedback signals can be achieved by the first MUX (115). After a data signal, such as local dimming data, is received, the signal can be processed by the first MUX (115) during an idle period.

[0159] For example, when a headroom voltage is detected in the detection unit (113) and a detection signal is output, a feedback signal may be output from the feedback detection unit (112). This feedback signal (FB Flag) may be transmitted to the MUX (115; first MUX).

[0160] In addition, a signal (FB_EN) notifying that a feedback signal has been generated from the feedback detection unit (112) may be generated and transmitted to the first MUX (115). The first MUX (115) may recognize the signal (FB_EN) notifying that such a feedback signal has been generated as 1.

[0161] In this way, the first MUX (115) can be controlled by the FB_EN signal. That is, the FB_EN signal can be a control signal of the first MUX (115). In this way, the data signal and the feedback signal can be time-divided and transmitted through the first MUX (115). For example, when the control signal of the first MUX (115) is 1 (FB_EN signal generation), the first MUX (115) can recognize that a feedback signal is input. Accordingly, the feedback signal can be transmitted to the second MUX (119) through the first MUX (115). On the other hand, when the control signal of the first MUX (115) is 0, the first MUX (115) can recognize this as a data signal, and the data signal can be processed and transmitted to the second MUX (119).

[0162] For example, when the input of the first MUX (115) is 1, the MUX (115) recognizes this as a feedback signal (FB_EN) and the feedback signal can be processed and transmitted to the second MUX (119). Meanwhile, when the input of the first MUX (115) is 0, the first MUX (115) recognizes this as a data signal and the data signal can be processed.

[0163] Meanwhile, when the minimum headroom voltage is detected (Min HR detection), the feedback signal can be converted into an analog signal (DAC_EN) in the DA converter (DAC; 118) of the driving element (110a).

[0164] The feedback signal converted into an analog signal through the DA converter (118) in this way can be transmitted to the second MUX (119). At this time, a signal (DAC_EN) notifying that a converted signal has been generated in the DA converter (118) can be generated and transmitted to the second MUX (119). The second MUX (119) can recognize this DAC_EN signal as 1.

[0165] In this way, the second MUX (119) can be controlled by the DAC_EN signal. In other words, the DAC_EN signal can be a control signal of the second MUX (119). In this way, the signal passing through the first MUX (115) and the feedback signal converted into analog can be transmitted in a time-segmented manner through the second MUX (119).

[0166] For example, when the control signal of the second MUX (119) is 1 (DAC_EN signal generation), the second MUX (119) can recognize that an analog converted feedback signal is input. Accordingly, the feedback signal can be transmitted to the output terminal (117) through the second MUX (119). This analog converted feedback signal (DAC OUT) can be transmitted within the same frame. For example, this analog converted feedback signal (DAC OUT) can be transmitted after the transmission of the next data signal divided within the same frame is completed.

[0167] Meanwhile, when the control signal of the second MUX (119) is 0, the second MUX (119) recognizes this as a data signal, and the data signal can be processed and transmitted to the output terminal (117).

[0168] In this way, when the FB EN signal is generated and a control signal of 1 is transmitted to the first MUX (115), and accordingly, a feedback signal is transmitted through the first MUX (115), and in the same way, when the DAC_EN signal is generated to the second MUX (119) and a control signal of 1 is transmitted to the second MUX (119), the analog-converted feedback signal (DAC OUT) can be transmitted to the output terminal (117).

[0169] The signal transmitted to the output terminal (117) in this way can be transmitted through the input terminal (116) of the neighboring driving element (110). The same operation as described above can be performed in the neighboring driving element (110). Finally, this output signal can be applied to the power supply (130).

[0170] Accordingly, the driving voltage (VLED) can increase. This process can occur between frames. Likewise, the feedback process based on headroom voltage detection can occur between frames. For example, this feedback process can occur between frames. Thus, the feedback signal can be transmitted multiple times within a single frame.

[0171] According to the present embodiment, a DA converter (DAC; 118) can be provided in each driving element (110a), so that the DAC voltage for controlling the driving voltage (VLED) in the current frame can be directly transmitted to the power supply (130) without going through the control unit. In addition, this feedback process can be transmitted in real time rather than after one frame (1 frame latency), so as to control the VLED voltage.

[0172] Figure 9 is a block diagram showing a data transmission process according to embodiments of the present disclosure.

[0173] Referring to FIG. 9, a display driving device (100, 101), for example, a flat lighting device (100, 101) or a backlight unit (BLU), can receive data from a main SoC (System on Chip; 140) that controls the device as a whole.

[0174] These data may include configuration data (DATA) and local dimming data for setting each driving element (110, 110a).

[0175] Local dimming data can be transmitted from the main SoC (140) to the control unit (120) located on the control board, and then transmitted to each driving element (110, 110a) through the control unit (120).

[0176] Meanwhile, configuration data (DATA) for setting each driving element (110, 110a) can be transmitted from the control unit (120) to each driving element (110, 110a). In the third embodiment described above, a separate control unit for setting each driving element (110a) can be provided.

[0177] FIG. 10 is a block diagram showing the physical connection status of a display driving device according to embodiments of the present disclosure.

[0178] Referring to FIG. 10, each driving element (110, 110a) can be connected to each other via an SPI (Serial Peripheral Interface) interface (111). For example, each driving element (110, 110a) can transmit and receive data by performing SPI (Serial Peripheral Interface) communication. For example, local dimming data for driving a flat lighting device (100, 101) or a backlight unit (BLU) can be transmitted via the SPI interface.

[0179] Accordingly, each driving element (110, 110a) may include an input terminal (SDI; 116) and an output terminal (SDO; 117) of an SPI interface (111). Each driving element (110, 110a) may be connected to each other through the input terminal (SDI) and the output terminal (SDO) of the SPI interface (111). For example, the output terminal (SDO) of one driving element (110, 110a) may be connected to the input terminal (SDI) of the neighboring driving element (10).

[0180] Referring to Fig. 10, the feedback operation based on the detection of the minimum headroom voltage of each driving element (110, 110a) is performed during the idle period of communication via the SPI interface (111), so a separate feedback terminal may not be required. Accordingly, a separate wire or jumper wire may not be required to connect these feedback terminals to each other.

[0181] As described above, according to the present embodiment, the driving voltage (VLED) can be controlled by transmitting a feedback signal to the power supply (130) periodically within each (video) frame unit or frame within each driving element (110, 110a).

[0182] Fig. 11 is a flowchart showing the operation process of a display driving device according to embodiments of the present disclosure.

[0183] Hereinafter, with reference to FIG. 3 or FIG. 7, the operation process of the display driving device according to the second or third embodiment of the present disclosure will be described.

[0184] First, the detection unit (113) can detect the minimum headroom voltage (S10). This minimum headroom voltage may correspond to a set minimum voltage required to drive a plurality of light-emitting element arrays (D1 to D8).

[0185] In this way, when the minimum headroom voltage is detected in the detection unit (113), a feedback signal is generated from the feedback detection unit (112), and a flag signal ('1') can be generated by this feedback signal (S20).

[0186] When these flag signals are generated and transmitted, the DA converter (DAC; 118 or 121) can detect (confirm) whether the DAC voltage / current has changed (S30).

[0187] In this way, when a change in DAC voltage / current occurs, the DAC voltage for controlling the step-up converter (DC-DC converter; 131) included in the power supply unit (130) can be adjusted (S40).

[0188] When the DAC voltage is adjusted in this way, the output voltage of the step-up converter (131) is adjusted, and accordingly, the driving voltage (VLED) is changed (S50), and the changed driving voltage (VLED) can be applied to the light-emitting element array (D1 to D8).

[0189] At this time, if the minimum headroom voltage is detected in any one of the channels to which the entire light-emitting element array (D1 to D8) is connected, a feedback signal according to the generation of this headroom voltage is transmitted to the power supply (130) to increase the driving voltage (VLED).

[0190] The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention, and are not necessarily limited to just one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment can be combined or modified in other embodiments by those skilled in the art to which the embodiments pertain. Therefore, the contents related to such combinations and modifications should be construed as falling within the scope of the present invention.

[0191] In addition, although the above description focuses on examples, these are merely examples and do not limit the present invention. Those skilled in the art to which the present invention pertains will appreciate that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present invention. For example, each component specifically shown in the examples can be modified and implemented. In addition, differences related to such modifications and applications should be interpreted as being included within the scope of the present invention defined in the appended claims.

[0192] According to the present disclosure, a display driving element and a display driving device using the same can be provided.

Claims

1. A plurality of driving elements including a channel to which one end of at least one light-emitting element array is connected; and It includes a power supply unit that is connected to the other end of the light emitting element array and supplies power, The above driving element is, A channel to which one end of at least one of the light-emitting element arrays is connected; SPI interface with input and output terminals; A detection unit connected to the channel to detect a headroom voltage for driving the light-emitting element array and output the detection signal; and It includes a feedback detection unit that receives the detection signal from the detection unit and outputs a feedback signal, A detection signal detecting the headroom voltage for driving the above light-emitting element array is output through the output terminal of the above SPI interface. Display driver.

2. In paragraph 1, The above driving element is, Further comprising a MUX for time division between the data signal transmitted through the SPI interface and the feedback signal, located between the SPI interface and the output terminal. Display driver.

3. In paragraph 2, The signal input from the output terminal of the neighboring driving element to the input terminal is transmitted to the MUX by logical combination with the feedback signal. Display driver.

4. In paragraph 1, The above detection signal is transmitted to the input of the power supply or neighboring driving element through the output terminal. Display driver.

5. In paragraph 1, The above driving element is, A first MUX located between the SPI interface and the output terminal for time division between a data signal transmitted through the SPI interface and the feedback signal; and Further comprising a second MUX for time division between the output signal of the first MUX and the detection signal. Display driver.

6. In paragraph 5, The above driving element is, Further comprising a DA converter located between the feedback detection unit and the second MUX. Display driver.

7. In paragraph 1, Further comprising a control unit positioned between the driving element and the power unit, and controlling the power unit by input of the detection signal. Display driver.

8. In paragraph 7, The above control unit transmits a signal to the power supply unit to increase the driving voltage for driving the light emitting element array when a detection signal detecting the headroom voltage is input. Display driver.

9. In paragraph 7, Data is periodically transmitted to the control unit through the SPI interface. Display driver.

10. In paragraph 9, The feedback signal is transmitted to the control unit during the pause period of the above data. Display driver.

11. In paragraph 9, The above feedback signal is transmitted to the control unit multiple times within a unit frame time. Display driver.

12. A channel to which one end of at least one light-emitting element array is connected; SPI interface with input and output terminals; A detection unit connected to the channel to detect a headroom voltage for driving the light-emitting element array and output the detection signal; and It includes a feedback detection unit that receives the detection signal from the detection unit and outputs a feedback signal, A detection signal detecting the headroom voltage for driving the above light-emitting element array is output through the output terminal of the above SPI interface. Display driving device.

13. In paragraph 12, Further comprising a MUX for time division between the SPI interface and the feedback signal, located between the SPI interface and the output terminal. Display driving device.

14. In paragraph 12, A first MUX located between the SPI interface and the output terminal for time division between the SPI interface and the feedback signal; and Further comprising a second MUX for time division between the output signal of the first MUX and the detection signal. Display driving device.

15. At least one light emitting element array comprising a plurality of rows of light emitting elements; A plurality of driving elements including a channel to which one end of the light emitting element array is connected, wherein the driving elements include an SPI interface having an input end and an output end, and output a detection signal detecting a headroom voltage for driving the light emitting element array through the output end; and A power supply unit that is connected to the other end of the light emitting element array and supplies power. Backlight driver.

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