LED driver and display device including same

Abstract

An LED driver according to an embodiment of the present disclosure may comprise: a plurality of channel terminals connected to a plurality of LEDs and each including a channel current source; a scan switch connected to the plurality of LEDs and configured for a scan operation; a plurality of scan terminals comprising first charge sharing switches for moving the charges of any one of a plurality of first capacitors forming capacitance between the plurality of LEDs and the scan switch to another first capacitor; and a switch controller for controlling the first charge sharing switches.

Description

LED driver and display device including same

[0001] The present disclosure relates to an LED driver and a display device including the same. More particularly, the present disclosure relates to an LED driver that minimizes power consumption and a display device including the same.

[0002] Display panels can be implemented in a variety of ways. For example, display panels can be classified as LCD display panels or LED display panels.

[0003] LED display panels can utilize mini LEDs or micro LEDs. This allows modular LED elements to be placed in the required number. Consequently, large-scale display devices, such as signage, can be easily implemented.

[0004] However, as display devices incorporate multiple LED modules, the number of LED drivers required can also be large. Therefore, reducing the power consumption of each LED driver is crucial.

[0005] In addition, as power consumption regulations in each country are becoming more stringent, the need for ways to reduce the power consumption of display devices is emerging.

[0006] The present disclosure seeks to minimize power consumption between scan operations of a scan unit.

[0007] The present disclosure seeks to minimize power consumption between scan operations of a scan stage by utilizing the charge of a capacitor.

[0008] An LED driver according to an embodiment of the present disclosure may include a plurality of channel stages connected to a plurality of LEDs and including a channel current source, a scan switch connected to a plurality of LEDs for a scan operation, a plurality of scan stages including a first charge sharing switch for transferring charge of one of a plurality of first capacitors forming a capacitance between the plurality of LEDs and the scan switch to another first capacitor, and a switch controller for controlling the first charge sharing switches.

[0009] An LED driver according to an embodiment of the present disclosure further includes a voltage generator for supplying a precharge voltage to a plurality of first capacitors, each of the plurality of scan stages further includes a precharge switch for precharging one of the plurality of first capacitors, and the switch controller may be configured to control the first charge sharing switches based on an operation of at least one of the scan switches and the precharge switches.

[0010] An LED driver according to an embodiment of the present disclosure may be configured such that one end of any one of the first charge sharing switches is connected between one end of any one of the precharge switches and one end of any one of the first capacitors, and the other end of any one of the first charge sharing switches may be connected to another first charge sharing switch.

[0011] An LED driver according to an embodiment of the present disclosure may be configured to turn on at least one of the first charge sharing switches when any one of the scan switches is turned off.

[0012] An LED driver according to an embodiment of the present disclosure can turn on a first charge sharing switch connected to an off scan switch among the first charge sharing switches.

[0013] An LED driver according to an embodiment of the present disclosure may be configured to turn on at least one of the first charge sharing switches from a point in time when at least one of the scan switches is turned off to a point in time when at least one of the precharge switches is turned on.

[0014] An LED driver according to an embodiment of the present disclosure may be configured to turn on a first charge sharing switch connected to a scan switch that is turned off and a first charge sharing switch connected to a precharge switch that is turned on, among the first charge sharing switches, at a time when at least one of the scan switches is turned off.

[0015] An LED driver according to an embodiment of the present disclosure may be configured to turn off a first charge sharing switch connected to an off scan switch and a first charge sharing switch connected to an on precharge switch when any one of the precharge switches is turned on.

[0016] Each of the plurality of channel stages of the LED driver according to an embodiment of the present disclosure further includes a second charge sharing switch for transferring charge of second capacitors forming electrostatic capacitance between each of the plurality of LEDs and each of the channel current sources to any one of the plurality of first capacitors, and the switch controller can further control the second charge sharing switches.

[0017] An LED driver according to an embodiment of the present disclosure may be configured to turn on all of the second charge sharing switches at a time when at least one of the first charge sharing switches is turned on.

[0018] An LED driver according to an embodiment of the present disclosure may be configured to turn off all of the second charge sharing switches at a time when at least one of the first charge sharing switches is turned off.

[0019] According to an embodiment of the present disclosure, an LED driver may be configured such that one end of each of the second charge-sharing switches is connected to each of the second capacitors, and the other end of each of the second charge-sharing switches is connected to each of the first charge-sharing switches.

[0020] A plurality of scan stages of an LED driver according to an embodiment of the present disclosure includes a first scan stage including a first scan switch and a 1-1 charge sharing switch, and a second scan stage including a second scan switch and a 1-2 charge sharing switch that performs a scan operation after a scan operation of the first scan stage is performed, and a plurality of first capacitors include a 1-1 capacitor connected to the 1-1 charge sharing switch and a 1-2 capacitor connected to the 1-2 charge sharing switch, and a switch controller can be set to turn on the 1-1 charge sharing switch and the 1-2 charge sharing switch when the first scan switch is turned off.

[0021] An LED driver according to an embodiment of the present disclosure may further include a voltage generator for supplying a precharge voltage to a plurality of first capacitors, a first scan stage may further include a first precharge switch for precharging the first-first capacitor, and a second scan stage may further include a second precharge switch for precharging the first-second capacitor.

[0022] The LED driver according to an embodiment of the present disclosure may be configured to turn off the first-first charge sharing switch and the first-second charge sharing switch when the first precharge switch is turned on.

[0023] Each of the plurality of channel stages of the LED driver according to an embodiment of the present disclosure further includes a second charge sharing switch for transferring charge of each of the plurality of second capacitors forming electrostatic capacitance between each of the plurality of LEDs and each of the channel current sources to any one of the plurality of first capacitors, and the switch controller may be set to turn on all of the second charge sharing switches at a time set to turn on the 1-1 charge sharing switch and the 1-2 charge sharing switch, and to turn off all of the second charge sharing switches at a time set to turn off the 1-1 charge sharing switch and the 1-2 charge sharing switch.

[0024] A display device according to an embodiment of the present disclosure may include a display panel including a plurality of LEDs, a plurality of channel terminals connected to the plurality of LEDs and including a channel current source, a scan switch connected to the plurality of LEDs and for a scan operation, an LED driver including a plurality of scan terminals including a first charge sharing switch for transferring charge of one of a plurality of first capacitors forming an electrostatic capacitance between the plurality of LEDs and the scan switch to another capacitor, and a switch controller for controlling the first charge sharing switches.

[0025] A display device according to an embodiment of the present disclosure further includes an LED driver including a voltage generator for supplying a precharge voltage to first capacitors, each of a plurality of scan stages further including a precharge switch for precharging one of the plurality of first capacitors, and a switch controller may be configured to control the first charge sharing switches based on an operation of at least one of the scan switches and the precharge switches.

[0026] A display device according to an embodiment of the present disclosure may be configured to turn on a first charge sharing switch connected to a scan switch that is turned off among the first charge sharing switches and a first charge sharing switch connected to a precharge switch that is to be turned on when at least one of the scan switches is turned off, and to turn off the first charge sharing switches that are turned on when any one of the precharge switches is turned on.

[0027] Each of the plurality of channel stages of the display device according to an embodiment of the present disclosure further includes a second charge sharing switch for transferring charge of each of the second capacitors forming electrostatic capacitance between each of the plurality of LEDs and each of the channel current sources to any one of the plurality of first capacitors, and the switch controller may be configured to further control the second charge sharing switches.

[0028] A display device according to an embodiment of the present disclosure may be configured to turn on all of the second charge sharing switches while turning on at least some of the first charge sharing switches.

[0029] According to one embodiment of the present disclosure, ghosting phenomenon can be prevented while minimizing power consumption.

[0030] According to one embodiment of the present disclosure, power and ground noise can be reduced, so that the output of the display panel can be stable.

[0031] According to one embodiment of the present disclosure, the scan operation order can be freely set, so that the influence of parasitic components of PCB routing can be minimized and applied.

[0032] Figure 1 is a configuration diagram of a display device according to one embodiment.

[0033] FIG. 2 is a drawing for explaining the scan frequency of an LED driver according to one embodiment of the present disclosure.

[0034] Figure 3 is a configuration diagram of an LED driver and a display panel.

[0035] Figure 4 is an operation timing diagram of the LED driver illustrated in Figure 3.

[0036] FIG. 5 is a drawing illustrating an LED driver and a display panel according to a first embodiment of the present disclosure.

[0037] FIG. 6 is an operation timing diagram of an LED driver according to a first embodiment of the present disclosure.

[0038] FIG. 7 is a diagram illustrating an LED driver and a display panel according to a second embodiment of the present disclosure.

[0039] Fig. 8 is an operation timing diagram of the LED driver illustrated in Fig. 7.

[0040] FIG. 9 is a table showing the power consumption rate of the LED driver according to the first and second embodiments of the present disclosure.

[0041] FIG. 1 is a configuration diagram of a display device according to an embodiment of the present disclosure.

[0042] Referring to FIG. 1, a display device (100) may include a power supply circuit (110), a data controller (120), an LED driver (130), a display panel (140), a scan line (SL), and a channel line (CL).

[0043] The power supply circuit (110) can supply power to the LED driver (130). The power supply circuit (110) can supply at least a portion of the driving power (Vcc) and the LED power (VLED) to the LED driver (130).

[0044] The driving power (Vcc) may be a power source for the operation of the display panel (140).

[0045] The LED power (VLED) may be a power source for controlling the brightness or color of a pixel (P). The LED power (VLED) may include a red LED power source (VLED_R) supplied to a subpixel expressing red, a green LED power source (VLED_G) supplied to a subpixel expressing green, and a blue LED power source (VLED_B) supplied to a subpixel expressing blue. However, this is merely an example, and the type of the LED power source (VLED) may vary depending on the embodiment.

[0046] The data controller (120) may be an LED pixel data controller.

[0047] The data controller (120) can obtain data related to the brightness or color of pixels (P) included in the display panel (140) and transmit the obtained data to the LED driver (130).

[0048] Alternatively, the data controller (120) may transmit at least some of the scan signal and data signal to the LED driver (130).

[0049] The scan signal may be a signal for supplying driving power (Vcc) to the display panel (140) through a scan line (SL).

[0050] The data signal may be a signal for supplying LED power (VLED) to the display panel (140) through a channel line (CL).

[0051] The LED driver (130) can generate a scan signal based on data related to the brightness or color of pixels (P) obtained from the data controller (120).

[0052] Alternatively, the LED driver (130) can receive a scan signal from the data controller (120).

[0053] The LED driver (130) may include a plurality of scan stages (200) and a plurality of channel stages (300).

[0054] The plurality of scan stages (200) may be the first scan stage to the mth scan stage (SCAN_1, SCAN_2, … SCAN_m-1, SCAN_m).

[0055] Each of the plurality of scan stages (200) can supply driving power (Vcc) to the display panel (140) based on a scan signal.

[0056] Each of the plurality of scan stages (200) can be connected to the display panel (140) through one scan line (SL). Each of the plurality of scan stages (200) can be sequentially connected in a vertical direction to the display panel (140) through one scan line (SL). Each of the plurality of scan stages (200) can supply driving power (Vcc) to the display panel (140) through one scan line (SL).

[0057] The plurality of channel groups (300) may be a first red channel group (CH_R1), a first green channel group (CH_G1), a first blue channel group (CH_B1), …, an nth red channel group (CH_Rn), an nth green channel group (CH_Gn), and an nth blue channel group (CH_Bn).

[0058] Each of the plurality of channel units (300) can supply LED power (VLED) to the display panel (140) based on a data signal.

[0059] Each of the plurality of channel units (300) can be connected to the display panel (140) through one channel line (CL). Each of the plurality of channel units (300) can be sequentially connected in a horizontal direction to the display panel (140) through one channel line (CL). Each of the plurality of channel units (300) can supply LED power (VLED) to the display panel (140) through one channel line (CL).

[0060] The display panel (140) may include a plurality of pixels (P).

[0061] Each of the plurality of pixels (P) may include a plurality of subpixels (R, G, B). For example, the pixel (P) may include a subpixel (R) representing red, a subpixel (G) representing green, and a subpixel (B) representing blue. However, the types of subpixels included in the pixel (P) are not limited thereto and may vary depending on the embodiment.

[0062] Each subpixel may include an LED. That is, the display panel (140) may be an LED display panel.

[0063] A plurality of pixels (P) can be connected horizontally via scan lines (SL). Additionally, a plurality of pixels (P) can be connected vertically via channel lines (CL). Accordingly, a plurality of pixels (P) can be arranged to form a matrix.

[0064] Pixels (P) connected horizontally through one scan line (SL) can receive driving power (Vcc) output from the same scan unit (200).

[0065] Pixels (P) connected vertically through one channel line (CL) can receive an LED voltage (VLED) output from the same channel unit (300).

[0066] FIG. 2 is a drawing for explaining the scan frequency of an LED driver according to one embodiment of the present disclosure.

[0067] A frame can refer to each image that makes up a video. A single frame can be divided into multiple segments.

[0068] A segment may be a unit in which one cycle of scanning operation is performed. The scanning operation may be an operation performed by turning on and then off a scan switch included in a scan stage. One cycle of scanning operation may mean that the scanning operation is performed sequentially once from the first scan stage (SCAN_1) to the mth scan stage (SCAN_m).

[0069] However, depending on the embodiment, the order of the scan operations may not be sequential from the first scan stage (SCAN_1) to the mth scan stage (SCAN_m). For example, the order of the scan operations may be determined taking into account the PCB routing.

[0070] Scan frequency can be the number of scan operations per second.

[0071] If the frame frequency is 60 Hz and the number of segments per frame is 64, 3840 scan operations can be performed per second. In other words, the scan frequency can be 3840 Hz.

[0072] The higher the scan frequency, the smoother the screen appears and the better the image quality appears.

[0073] However, as the scan frequency increases, the power consumption of the LED driver (130) may also increase.

[0074] This is because a pre-charge operation is performed between scan operations to prevent ghosting, and current is consumed each time a pre-charge operation is performed.

[0075] Ghosting may refer to a phenomenon in which a pixel (P) connected to a scan unit (200) that is not in scanning operation lights up. Accordingly, the desired screen may not be accurately displayed, and the image quality may appear to be degraded.

[0076] Precharge may refer to an operation of charging the first capacitor (C1) connected to a scan stage where a scan operation has ended before a scan operation of another scan stage begins. Precharge may be performed between the time when a scan operation ends and the time when the next scan operation begins.

[0077] Next, with reference to FIGS. 3 and 4, the precharge operation and the resulting current consumption will be described.

[0078] Figure 3 is a configuration diagram of an LED driver and a display panel.

[0079] The display device (100) may include an LED driver (130) and a display panel (140).

[0080] The display panel (140) may include a plurality of pixels (P) and a plurality of capacitors (C).

[0081] The plurality of capacitors (C) may be parasitic capacitors of the LED module. The plurality of capacitors (C) may be capacitors that form electrostatic capacitance within the display device (100) according to the operation of the LED driver (130) or the display panel (140). These capacitors (C) may be virtual capacitors rather than physical capacitors.

[0082] The plurality of capacitors (C) may be divided into a plurality of first capacitors (C1) that form capacitance between the plurality of LEDs and the scan switch, and a second capacitor (C2) that forms capacitance between the plurality of LEDs and the channel current source. The plurality of capacitors (C) may be interpreted as being electrically connected to other components included in the present disclosure.

[0083] The plurality of capacitors (C) may be a plurality of first capacitors (C1) connected to a plurality of scan stages (200).

[0084] Additionally, the plurality of capacitors (C) may be a plurality of second capacitors (C2) connected to a plurality of channel terminals (300).

[0085] The plurality of first capacitors (C1) may be 1-1, 1-2, 1-3, and 1-4 capacitors (C11, C12, C13, C14). However, the number of the plurality of first capacitors (C1) may vary depending on the number of scan stages (200) or scan lines (SL).

[0086] The LED driver (130) can perform a precharge operation to charge the capacitor (C) to prevent ghosting. Specifically, the LED driver (130) can perform a precharge operation to charge the first capacitor (C1).

[0087] By pre-charging the first capacitor (C1), the voltage (VN) of the first capacitor may increase. Accordingly, the pixel (P) connected to the first capacitor (C1) may be maintained in a reverse bias state, so that no current may flow to the pixel (P). Accordingly, the pixel (P) connected to the first capacitor (C1) may not light up.

[0088] The LED driver (130) may include a plurality of scan stages (200), a plurality of channel stages (300), and a voltage generator (400).

[0089] The voltage generator (400) may be a voltage generator for generating a precharge voltage (V_CHARGE). The precharge voltage (V_CHARGE) may be a voltage for charging a capacitor (C). Specifically, the precharge voltage (V_CHARGE) may be a voltage for charging a first capacitor (C1). The voltage generator (400) may supply a precharge voltage to a plurality of first capacitors (C1).

[0090] The voltage generator (400) can generate a precharge voltage (V_CHARGE) using the driving power (Vcc) supplied from the power supply circuit (110). Accordingly, a precharge current (I_CHARGE) can be output from the output terminal of the voltage generator (400).

[0091] The voltage generator (400) can supply a precharge current (I_CHARGE) to the scan stage (200). The precharge current (I_CHARGE) supplied to the scan stage (200) can be supplied to the first capacitor (C1) through the scan line (SL). Accordingly, the first capacitor (C1) can be charged.

[0092] The plurality of scan stages (200) may be the first to fourth scan stages. However, the number of scan stages (200) is merely an example and is not limited thereto.

[0093] Each of the plurality of scan switches (200) may include a scan switch (210) and a precharge switch (220).

[0094] The scan switch (210) may be a switch for scanning operation.

[0095] Depending on the operation of the scan switch (210), the driving power (Vcc) can be output through one of the plurality of scan lines (SL). That is, the scan line (SL) that supplies the driving power (Vcc) can be determined depending on the operation of the scan switch (210).

[0096] The precharge switch (220) may be a switch for precharging the first capacitor (C1). As the precharge switch (220) is turned on, the first capacitor (C1) may be precharged.

[0097] Depending on the operation of the precharge switch (220), a capacitor to be precharged among the plurality of first capacitors (C1) can be determined. When any one of the plurality of precharge switches (200) is turned on, any one of the first capacitors (C1) connected to the turned-on precharge switch can be precharged. Accordingly, the first capacitor voltage (VN) of the first capacitor (C1) connected to the turned-on precharge switch (220) can increase.

[0098] One end of the scan switch (210) can be connected to the ground, and the other end of the scan switch (210) can be connected to one end of the precharge switch (220).

[0099] One end of the precharge switch (220) can be connected to one end of the scan switch (210).

[0100] Additionally, one end of the precharge switch (220) can be connected to one end of the first capacitor (C1).

[0101] One end of the precharge switch (220) can be connected between the scan switch (210) and the first capacitor (C1).

[0102] The other end of the precharge switch (220) may be connected to the output end of the voltage generator (400). In addition, the other end of the precharge switch (220) may be connected to one end of another precharge switch (220). That is, the other end of the precharge switch (220) may be connected to the output end of the voltage generator (400) and one end of another precharge switch (220).

[0103] One end of the first capacitor (C1) may be connected to one end of the precharge switch (210). In addition, one end of the first capacitor (C1) may be connected to the pixel (P). That is, one end of the first capacitor (C1) may be connected between the precharge switch (210) and the pixel (P).

[0104] The other terminal of the first capacitor (C1) can be grounded.

[0105] The plurality of channel units (300) may include the first to ninth channel units. However, the number of channel units (300) is merely an example and is not limited thereto.

[0106] Each of the plurality of channel stages (300) may include a channel current source (310) and a PWM switch (Pulse Width Modulation Switch, 320).

[0107] The channel current source (310) can generate a channel current using an LED power source (VLED). The channel current generated from each channel current source (310) can be supplied to pixels (P) connected in a vertical direction through one channel line (CL).

[0108] Each of the plurality of channel lines (CL) may include a PWM switch (320).

[0109] The PWM switch (320) may be a switch for controlling the output of channel current.

[0110] Depending on the operation of the PWM switch (320), channel current may be output from at least some of the plurality of channel stages (300).

[0111] Additionally, the amount of channel current supplied through each channel line (CL) can be determined depending on the time the PWM switch (320) is turned on. Accordingly, the brightness or color of the pixel (P) can be determined.

[0112] The channel current source (310) can be connected in series between the LED voltage (VLED_R / G / B) and the PWM switch (320).

[0113] A PWM switch (320) can be connected in series between a pixel (P) and a channel current source (310).

[0114] Figure 4 is an operation timing diagram of the LED driver illustrated in Figure 3.

[0115] FIG. 4 may be a drawing showing the operation timing when the first to fourth scan stages sequentially perform scan operations.

[0116] First, the first scan unit can perform a scan operation. For this purpose, the first scan switch (211) can be operated. The first scan switch (211) can be turned on or off based on a scan signal.

[0117] The first scan line may be connected to the first-first capacitor (C11) through one scan line (SL). The voltage of the first-first capacitor (C11) may be the first-first capacitor voltage (VN1).

[0118] The first-first capacitor voltage (VN1) can rapidly decrease from the point in time when the first scan switch (211) is turned on, and can reach a minimum value before the point in time when the first scan switch (211) is turned off. The first-first capacitor voltage (VN1) can be maintained at a minimum value until the point in time when the first scan switch (211) is turned off.

[0119] The first precharge switch (221) may be turned on at the time when the first scan switch (211) is turned off. Accordingly, precharge of the first-1 capacitor (C11) may be initiated.

[0120] From the point when the first precharge switch (221) is turned on, the charging current (I_CHARGE_VN1) for charging the 1-1 capacitor (C11) may rapidly increase. Accordingly, the 1-1 capacitor (C11) may be charged. The charging current (I_CHARGE_VN1) for charging the 1-1 capacitor (C11) may decrease again as the charge amount of the 1-1 capacitor (C11) increases.

[0121] As the charge amount of the first capacitor (C11) increases, the first capacitor voltage (VN1) may increase. The first capacitor voltage (VN1) may reach a maximum value before the second scan switch (212) turns on. The first capacitor voltage (VN1) may be maintained at the maximum value until the first scan stage performs a scan operation again.

[0122] In summary, the first-first capacitor (C11) can be precharged between the time when the first scan switch (211) turns off and the time when the second scan switch (212) turns on.

[0123] The time for which the first capacitor (C1) is precharged may be a precharge time (tp). The precharge time (tp) may be determined as the time between the time when one scan switch (210) turns off and the time when another scan switch (210) turns on. The precharge time (tp) may be determined by considering the scan operation time, the capacity of the first capacitor (C1), the size of the driving power (Vcc), etc.

[0124] As the first capacitor (C1) is precharged, the first capacitor voltage (VN) maintains a maximum value, so that the pixels (P) connected to the first capacitor (C1) maintain a reverse bias state, thereby preventing a ghost phenomenon.

[0125] However, as the capacitor charging current (I_CHARGE) consumed during the precharge time (tp) increases rapidly, the power consumption of the LED driver (130) may increase.

[0126] Additionally, the higher the scan frequency, the more precharges there are, and therefore, the more frequently the charging current (I_CHARGE) is consumed. In other words, the higher the scan frequency, the more power consumption there may be.

[0127] Accordingly, the present disclosure aims to provide an LED driver (130) capable of operating at low power while performing a precharge operation to prevent ghosting.

[0128] To this end, the LED driver (130) and the display device (100) including the same according to the embodiment of the present disclosure can control a plurality of charge sharing switches (600).

[0129] First, an LED driver (130) according to a first embodiment of the present disclosure will be described with reference to FIGS. 5 and 6.

[0130] FIG. 5 is a drawing illustrating an LED driver and a display panel according to a first embodiment of the present disclosure.

[0131] The LED driver (130) according to the first embodiment of the present disclosure may further include a switch controller (500) and a charge sharing switch (600) compared to the LED driver (130) of FIG. 4.

[0132] The switch controller (500) can control charge sharing switches (600). The switch controller (500) can control the on / off of each of a plurality of charge sharing switches (600).

[0133] The charge sharing switch (600) may be a switch for charge sharing between capacitors (C).

[0134] The charge sharing switch (600) may include a first charge sharing switch (610).

[0135] The first charge sharing switch (610) may be a switch for moving charges between a plurality of first capacitors (C1).

[0136] The first charge sharing switch (610) may be a switch for moving the charge of one of the plurality of first capacitors (C1) to another first capacitor.

[0137] One end of the first charge sharing switch (610) can be connected to one end of the precharge switch (220).

[0138] Additionally, one end of the first charge sharing switch (610) can be connected to one end of the first capacitor (C1).

[0139] The other end of the first charge sharing switch (610) can be connected to one end of another first charge sharing switch (610).

[0140] That is, one end of the first charge sharing switch (610) is connected between one end of the precharge switch (220) and one end of the first capacitor (C1), and the other end of the first charge sharing switch (610) can be connected to another first charge sharing switch (610).

[0141] The first charge sharing switch (610) may be the 1-1, 1-2, 1-3 and 1-4 charge sharing switches (611, 612, 613, 165).

[0142] The 1-1 charge sharing switch (611) may be a charge sharing switch (610) included in the first scan stage.

[0143] The first-second charge sharing switch (612) may be a charge sharing switch (610) included in the second scan stage.

[0144] The 1-3 charge sharing switch (613) may be a charge sharing switch (610) included in the 3rd scan stage.

[0145] The 1-4 charge sharing switch (614) may be a charge sharing switch (610) included in the first scan stage.

[0146] The number of first charge sharing switches (610) is merely an example and may vary depending on the number of scan stages (200).

[0147] To summarize FIG. 5, the LED driver (130) according to the first embodiment of the present disclosure may include a plurality of channel stages (300) connected to a plurality of LEDs and including a channel current source (310), a scan switch (210) connected to a plurality of LEDs for a scan operation, a plurality of scan stages (200) including a first charge sharing switch (610) for transferring charge of one of a plurality of first capacitors (C1) forming electrostatic capacitance between the plurality of LEDs and the scan switch (210) to another first capacitor (C1), and a switch controller (500) for controlling the first charge sharing switches (610).

[0148] In addition, the LED driver (130) according to the first embodiment of the present disclosure includes a voltage generator (400) that supplies a precharge voltage to a plurality of first capacitors (C1), and each of the plurality of scan stages (200) may include a precharge switch (220) for precharging any one of the plurality of first capacitors (C1).

[0149] As described above, the operation of the first charge sharing switches (610) can be controlled by the switch controller (500).

[0150] The switch controller (500) may be configured to control the first charge sharing switches (610) based on the operation of at least one of the first scan switches (210) and the precharge switches (220).

[0151] For example, the switch controller (500) may be configured to turn on at least one of the first charge sharing switches (610) when any one of the scan switches (210) is turned off.

[0152] Specifically, the switch controller (500) can be set to turn on the first charge sharing switch (610) connected to the scan switch (210) that is turned off among the first charge sharing switches (610).

[0153] Additionally, the switch controller (500) may be set to turn on at least one of the first charge sharing switches (610) from the time at least one of the scan switches (210) is turned off to the time at least one of the precharge switches (220) is turned on.

[0154] Specifically, the switch controller (500) may be set to turn on the first charge sharing switch (610) connected to the scan switch (220) that is turned off among the first charge sharing switches (610) and the first charge sharing switch (610) connected to the precharge switch (220) that is turned on at a time when at least one of the scan switches (610) is turned off.

[0155] Additionally, the switch controller (500) can be set to turn off the first charge sharing switch (610) connected to the scan switch (220) that is turned off and the first charge sharing switch (610) connected to the precharge switch (220) that is turned on when any one of the precharge switches (220) is turned on.

[0156] Next, referring to FIG. 6, charge sharing between the first capacitors (C1) will be specifically described using the first-1 capacitor (C11) and the first-2 capacitor (C12) as examples.

[0157] As illustrated in FIG. 5, the 1-1 capacitor (C11) may be a capacitor (C) connected to the 1-1 charge sharing switch (611) included in the 1st scan stage.

[0158] Additionally, the 1-2 capacitor (C12) may be a capacitor (C) connected to the 1-2 charge sharing switch (612) included in the 2nd scan stage.

[0159] FIG. 6 is an operation timing diagram of an LED driver according to a first embodiment of the present disclosure.

[0160] FIG. 6 may be a diagram further illustrating the operation timing of the first charge sharing switches (610) compared to the timing diagram of FIG. 4.

[0161] Referring to FIG. 6, the scan operation of the second scan stage can be performed after the scan operation of the first scan stage is performed.

[0162] First, for the scan operation of the first scan stage, the first scan switch (211) can be operated. The first scan switch (211) can be turned on or off based on a scan signal.

[0163] The first-first capacitor voltage (VN1) rapidly decreases from the point at which the first scan switch (211) is turned on, and can reach the minimum value before the point at which the first scan switch (211) is turned off.

[0164] The first-first capacitor voltage (VN1) can be maintained at a minimum value until the first scan switch (211) is turned off.

[0165] Meanwhile, the 1-2 capacitor voltage (VN2) can maintain a maximum value from the time the 1st scan switch (211) is turned on to the time the 1st scan switch (212) is turned off. This may mean that the 1-2 capacitor (C12) maintains a fully charged state while the 1st scan stage performs a scan operation.

[0166] The switch controller (500) can be set to turn on the first-1 and first-2 charge sharing switches (611, 612) when the first scan switch (211) is turned off.

[0167] During the time that the 1-1 and 1-2 charge sharing switches (611, 612) are turned on, the 1-2 capacitor voltage (VN2) may decrease. In addition, the 1-1 capacitor voltage (VN1) may increase as much as the 1-2 capacitor voltage (VN2) decreases.

[0168] This may mean that the charge charged in the 1-2 capacitor (C12) moves to the 1-1 capacitor (C11), and the 1-1 capacitor (C11) is charged.

[0169] The charge charged in the 1-2 capacitor (C12) can move to the 1-1 capacitor (C11) until the 1-1 capacitor voltage (VN1) and the 1-2 capacitor voltage (VN2) become equal.

[0170] Accordingly, the voltage of the first-second capacitor (VN2) can be reduced to half of the maximum capacitor voltage. In addition, the voltage of the first-first capacitor (VN1) can be increased to half of the maximum capacitor voltage.

[0171] The time for charges to move between the first capacitors (C1) may be a charge sharing time (ts). The charge sharing time (ts) may be the time from when at least a portion of the charge sharing switch (610) is turned on to when it is turned off.

[0172] The charge sharing time (ts) can be determined by considering the precharge time (tp), scan operation time, capacity of the capacitor (C), size of the driving power (Vcc), etc.

[0173] For example, the point in time at which the switch controller (500) turns off the first-1 and first-2 charge sharing switches (611, 612) can be set to the point in time at which the first precharge switch (221) turns on.

[0174] Alternatively, depending on the embodiment, the point in time at which the switch controller (500) turns off the first-first and first-second charge sharing switches (611, 612) may be set to a point in time at which the first-first capacitor voltage (VN1) and the first-second capacitor voltage (VN2) are expected to become equal.

[0175] Accordingly, the 1-1 capacitor (C11) is charged by the charging current (I_CHARGE_VN1), so that the 1-1 capacitor voltage (VN1) can reach the maximum value. The 1-1 capacitor voltage (VN1) can reach the maximum value at the time when the second scan switch (212) is turned on.

[0176] That is, the first-first capacitor (C11) can be precharged from the time when the charge sharing time (ts) ends until the time when the second scan switch (212) turns on.

[0177] The precharge time (tp) may be the time from the time when the charge sharing time (ts) ends to the time when one of the scan switches (210) turns on.

[0178] Alternatively, the precharge time (tp) may be the time from the end of the charge sharing time (ts) to the point at which the capacitor voltage (VN) reaches its maximum value.

[0179] That is, the precharge time (tp) of FIG. 6 may be shorter than the precharge time (tp) of FIG. 4.

[0180] Therefore, when comparing the capacitor charging current (I_CHARGE_VN) consumed during the precharge time (tp) of FIGS. 4 and 6, it can be confirmed that the capacitor charging current (I_CHARGE_VN) of FIG. 6 is consumed less.

[0181] From this, it can be confirmed that the LED driver (130) and the display device (100) including the same according to the first embodiment of the present disclosure can reduce power consumption by including a charge sharing switch (610).

[0182] The effect of reducing power consumption in this way can be more noticeable when the display device (100) is an LED display device such as signage.

[0183] Signage may be a large display device containing hundreds to tens of thousands of LED drivers (130). Therefore, if the power consumption of one LED driver (130) is reduced, the power consumption of the entire display device can be significantly reduced.

[0184] An LCD display device can contain dozens of drivers. For example, an LCD display device may contain 20 drivers. If the current consumption of each driver is reduced, for example, from 2 mA to 1 mA, the current consumption of the entire display device is reduced by 20 mA.

[0185] On the other hand, a signage may include hundreds to tens of thousands of LED drivers (130). For example, a signage may include 10,000 LED drivers (130). In this case, if the current consumption of each LED driver (130) is reduced from, for example, 2 mA to 1 mA, the current consumption of the entire display device is reduced by 10 A.

[0186] Additionally, as the current consumption decreases, the heat generation problem of the display device (100) can be improved.

[0187] In addition, when comparing the maximum values ​​of the capacitor charging current (I_CHARGE_VN) consumed during the precharge time (tp) of FIGS. 4 and 6, it can be seen that the capacitor charging current (I_CHARGE_VN) of FIG. 6 has a smaller maximum value.

[0188] The smaller the maximum value of the charging current (I_CHARGE_VN), the more power and ground noise can be reduced. Accordingly, the output of the display panel (140) can be stable. This effect can be particularly noticeable when outputting in low-grayscale image quality.

[0189] That is, the LED driver (130) according to the first embodiment of the present disclosure and the display device (100) including the same include a charge sharing switch (610), thereby enabling the output of the display panel (140) to have a stable effect.

[0190] As described above, during the charge sharing time (ts), the first capacitor voltage (VN) may increase as it shares charge from another capacitor (C).

[0191] Additionally, during the precharge time (tp), the first capacitor voltage (VN) may increase as the charging current (I_CHARGE) is supplied. Therefore, the graph of the first capacitor voltage (VN) between scan operations may be distinguished based on the point in time when the charge sharing time (ts) ends.

[0192] Meanwhile, if the LED driver (130) does not include a charge sharing switch (600) or does not include a charge sharing switch (600), the first capacitor voltage (VN) may increase as the charging current (I_CHARGE) is supplied. Accordingly, the graph of the first capacitor voltage (VN) between scan operations may be a continuous graph.

[0193] Next, an LED driver (130) according to a second embodiment of the present disclosure will be described with reference to FIGS. 7 and 8.

[0194] FIG. 7 is a diagram illustrating an LED driver and a display panel according to a second embodiment of the present disclosure.

[0195] The LED driver (130) according to the second embodiment of the present disclosure further includes a plurality of second charge sharing switches (620) compared to the LED driver (130) of FIG. 5.

[0196] Additionally, the display panel (140) according to the second embodiment of the present disclosure further includes a plurality of second capacitors (C2) compared to the display panel (140) of FIG. 5.

[0197] Each of the plurality of second capacitors (C2) may be a capacitor that forms an electrostatic capacitance between each of the plurality of LEDs and each of the channel current sources (310).

[0198] The plurality of charge sharing switches (600) may be a first charge sharing switch (610) and a second charge sharing switch (620).

[0199] The second charge sharing switch (620) may be a switch for moving the charge of each of the second capacitors (C2) to one of the first capacitors (C1).

[0200] One end of the second charge sharing switch (620) may be connected to one end of the PWM switch (320). In addition, one end of the second charge sharing switch (620) may be connected to the pixel (P). That is, one end of the second charge sharing switch (620) may be connected between the PWM switch (320) and the pixel (P).

[0201] The other end of the second charge sharing switch (620) can be connected to one end of another second charge sharing switch (620).

[0202] Additionally, the other end of the second charge sharing switch (620) can be connected to one end of the first charge sharing switch (610).

[0203] The plurality of second charge sharing switches (620) may be 2-1, 2-2, 2-3, 2-4, 2-5, 2-6, 2-7, 2-8, 2-9 charge sharing switches (621, 622, 623, 624, 625, 626, 627, 628, 629).

[0204] The 2-1 charge sharing switch (621) may be a charge sharing switch (600) included in the first channel unit.

[0205] The second-second charge sharing switch (622) may be a charge sharing switch (600) included in the second channel unit.

[0206] The 2nd-3rd charge sharing switch (623) may be a charge sharing switch (600) included in the 3rd channel stage.

[0207] The 2-4 charge sharing switch (624) may be a charge sharing switch (600) included in the 4th channel unit.

[0208] The 2-5 charge sharing switch (625) may be a charge sharing switch (600) included in the 5th channel stage.

[0209] The 2-6 charge sharing switch (626) may be a charge sharing switch (600) included in the 6th channel unit.

[0210] The 2-7 charge sharing switch (621) may be a charge sharing switch (600) included in the 7th channel unit.

[0211] The 2-8 charge sharing switch (621) may be a charge sharing switch (600) included in the 8th channel unit.

[0212] The 2-9 charge sharing switch (621) may be a charge sharing switch (600) included in the 9th channel unit.

[0213] The number of second charge sharing switches (620) is only an example and may vary depending on the number of channel stages.

[0214] The second charge sharing switch (620) can be controlled by the switch controller (500).

[0215] For example, the switch controller (500) may be configured to turn on all of the second charge sharing switches (620) at the time at least one of the first charge sharing switches (610) is turned on.

[0216] Additionally, the switch controller (500) may be configured to turn off all of the second charge sharing switches (620) at the time at which at least one of the first charge sharing switches (610) is turned off.

[0217] Accordingly, the charge of all of the second capacitors (C2) can move to any one of the first capacitors (C1).

[0218] Next, with reference to FIG. 8, a method of moving the charge of the second capacitors (C2) to one of the first capacitors (C1) will be described in detail.

[0219] Fig. 8 is an operation timing diagram of the LED driver illustrated in Fig. 7.

[0220] Fig. 8 may be a diagram further illustrating the operation timing of the second charge sharing switch (620) compared to the timing diagram of Fig. 6.

[0221] All of the plurality of second charge sharing switches (620) can be turned on during the charge sharing time (ts). Accordingly, the charge of all of the plurality of second capacitors (C2) can be transferred to any one of the first capacitors (C1).

[0222] The charge sharing time (ts) may be a time during which at least some of the plurality of first charge sharing switches (610) or all of the plurality of second charge sharing switches (620) are turned on.

[0223] Next, charge sharing between the first capacitor (C1) and the second capacitor (C2) will be specifically explained using the first-1 capacitor (C11) and the first-2 capacitor (C12) as examples.

[0224] When the first scan switch (211) is turned off, the first-1 and first-2 charge sharing switches (611, 612) can be turned on.

[0225] Additionally, all of the plurality of second charge sharing switches (620) can be turned on.

[0226] During the time when the 1st and 1st charge sharing switches (611, 612) are turned on, the 1st and 2nd capacitor voltage (VN2) may decrease.

[0227] Likewise, while the second charge sharing switch (620) is turned on, the capacitor voltage of the second capacitors (C2) may also decrease.

[0228] This may mean that the charge charged in all of the first-second capacitor (C12) and the plurality of second capacitors (C2) moves to the first-first capacitor (C11), so that the first-first capacitor (C11) is charged.

[0229] Accordingly, the 1-1 capacitor voltage (VN1) may increase.

[0230] Additionally, the increase in the 1-1 capacitor voltage (VN1) may be greater than the increase in the 1-1 capacitor voltage (VN1) of Fig. 6. That is, the 1-1 capacitor voltage (VN1) may increase to a value greater than half of the maximum capacitor voltage.

[0231] Meanwhile, the amount of increase in the first-first capacitor voltage (VN1) may vary depending on the capacity of the first capacitor (C1) or the second capacitor (C2).

[0232] When the charge sharing time (ts) elapses from the time the first scan switch (211) is turned off, the first-1, first-2 charge sharing switches (611, 612) and a plurality of second charge sharing switches (620) can be turned off.

[0233] The charge sharing time (ts) may be the same time as the charge sharing time (ts) of FIG. 6.

[0234] The first precharge switch (211) can be turned on when the first and second charge sharing switches (611, 612) and the plurality of second charge sharing switches (620) are turned off.

[0235] Accordingly, the 1-1 capacitor (C11) is charged by the charging current (I_CHARGE_VN1), so that the 1-1 capacitor voltage (VN1) can reach the maximum value. The 1-1 capacitor voltage (VN1) can reach the maximum value at the time when the second scan switch (212) is turned on.

[0236] That is, the first-first capacitor (C11) can be precharged from the time when the charge sharing time (ts) ends until the time when the second scan switch (212) turns on.

[0237] The precharge time (tp) of Fig. 8 may be the same as the precharge time (tp) of Fig. 6.

[0238] Comparing the capacitor charging current (I_CHARGE) consumed during the precharge time (tp) of FIG. 6 and FIG. 8, it can be confirmed that the capacitor charging current (I_CHARGE_VN) of FIG. 8 is consumed less.

[0239] That is, the LED driver (130) and the display device (100) including the same according to the second embodiment of the present disclosure can further reduce power consumption by further including a second charge sharing switch (620).

[0240] In addition, when comparing the capacitor charging current (I_CHARGE) consumed during the precharge time (tp) of FIG. 6 and FIG. 8, it can be seen that the capacitor charging current (I_CHARGE_VN) of FIG. 8 has a smaller maximum value.

[0241] That is, the LED driver (130) according to the second embodiment of the present disclosure and the display device (100) including the same can have a more stable output effect of the display panel (140) than when the second charge sharing switch (620) is not included.

[0242] Referring to FIG. 9, the power consumption of the LED driver according to the first and second embodiments of the present disclosure is described.

[0243] FIG. 9 is a table showing the power consumption rate of the LED driver according to the first and second embodiments of the present disclosure.

[0244] The measurement conditions of Fig. 9 are, for example, that the capacity (C_LOAD) of the first capacitor is 5 nF, the first capacitor charge voltage (V_CHARGE) is 3 V, the scan frequency (Freq_Scanning) is 2840 Hz, the number of scans (SCAN_k) is 20 scans, and the input power (Vcc) is 5 V.

[0245] The consumption current (ISwitching_Consumption) of the scan switch (210) can be calculated using the mathematical expression 1 below.

[0246]

[0247] The consumption current (ISwitching_Consumption) of the scan switch (210) is 1.15 mA when the first capacitor (C1) does not share charge. 1.15 mA may be the reference consumption current.

[0248] According to the first embodiment, when the first capacitor (C1) shares a charge corresponding to 1.5 V, the consumption current (ISwitching_Consumption) of the scan switch (210) is 0.58 mA, and according to the second embodiment, when the first capacitor (C1) shares a charge corresponding to 1.8 V, the consumption current (ISwitching_Consumption) of the scan switch (210) is 0.6 mA.

[0249] The consumption current (ISwitching_Consumption) of the scan switch (210) according to the first embodiment is 50% of the reference consumption current, and the consumption current (ISwitching_Consumption) of the scan switch (210) according to the second embodiment is 40% of the reference consumption current.

[0250] Power consumption of the first capacitor (P CLOAD ) can be calculated using the mathematical formula 2 below.

[0251]

[0252] Power consumption of the first capacitor (P CLOAD ) is 5.76 mW when the first capacitor (C1) does not share charge. 5.76 mW may be the reference power consumption.

[0253] For example, if the first capacitor (C1) shares a charge corresponding to 1.5 V according to the first embodiment, the power consumption (P) of the first capacitor CLOAD ) is 2.88 mW, and when the first capacitor (C1) shares a charge corresponding to 1.8 V according to the second embodiment, the power consumption (P) of the first capacitor CLOAD ) is 2.30mW.

[0254] Power consumption (P) of the first capacitor according to the first embodiment CLOAD ) is 50% of the standard power consumption, and the power consumption of the first capacitor according to the second embodiment (P CLOAD ) is 50% of the standard power consumption.

[0255] The power consumption of the LED driver (130) is the current consumption of the scan switch (210) (ISwitching_Consumption) or the power consumption of the first capacitor (P CLOAD ) can be proportional to.

[0256] That is, it can be confirmed that the power consumption rate of the LED driver (130) according to the first and second embodiments of the present disclosure is significantly reduced compared to the LED driver that does not share charges between capacitors (C).

[0257] Meanwhile, for convenience of explanation, in FIGS. 6 and 8, it is assumed that multiple scan stages sequentially perform scanning operations. However, the order in which multiple scan stages perform scanning operations can be determined in various ways.

[0258] For example, the order in which multiple scan stages perform scan operations may vary depending on the LED module PCB routing included in the display panel (140).

[0259] When determining the order in which multiple scan stages perform scan operations by considering the LED module PCB routing, the influence of parasitic components such as resistance of the scan stages can be minimized.

[0260] The LED driver (130) according to an embodiment of the present disclosure and the switch controller (500) of the display device (100) including the same can freely control each of the plurality of first charge sharing switches (610) and the plurality of second charge sharing switches (620).

[0261] Accordingly, the LED driver (130) and the display device (100) including the same according to the embodiment of the present disclosure can perform a charge sharing operation regardless of the operation order of the plurality of scan stages (200).

[0262] That is, the LED driver (130) and the display device (100) including the same according to the embodiment of the present disclosure have the advantage of being able to freely set the output order of the scan stage (200), thereby minimizing the influence of parasitic components of PCB routing and minimizing current consumption between scan operations.

[0263] The LED driver disclosed in the present disclosure and the display device including the same have the advantage of minimizing the influence of parasitic components of PCB routing while minimizing current consumption between scan operations, and thus have industrial applicability.

Claims

1. A plurality of channel terminals connected to a plurality of LEDs and including a channel current source; A plurality of scan stages including a scan switch for scanning operation, a first charge sharing switch for transferring charge of one of a plurality of first capacitors that are connected to the plurality of LEDs and form a capacitance between the plurality of LEDs and the scan switch to another first capacitor; and A switch controller comprising a switch controller that controls the first charge sharing switches. LED driver.

2. In claim 1, The above LED driver Further comprising a voltage generator for supplying a precharge voltage to the plurality of first capacitors, Each of the plurality of scan stages further includes a precharge switch for precharging one of the plurality of first capacitors, The above switch controller Set to control the first charge sharing switches based on the operation of at least one of the scan switches and the precharge switches. LED driver.

3. In claim 2, One end of any one of the first charge sharing switches is connected between one end of any one of the precharge switches and one end of any one of the first capacitors, and the other end of any one of the first charge sharing switches is connected to another first charge sharing switch. LED driver.

4. In claim 2, The above switch controller At least one of the first charge sharing switches is set to turn on when any one of the scan switches is turned off. LED driver.

5. In claim 4, The above switch controller Turning on the first charge sharing switch connected to the scan switch that is turned off among the first charge sharing switches LED driver.

6. In claim 4, The above switch controller At least one of the first charge sharing switches is set to be turned on from the time at least one of the scan switches is turned off until the time at least one of the precharge switches is turned on. LED driver.

7. In claim 6, The above switch controller At a time when at least one of the scan switches is turned off, the first charge sharing switch connected to the scan switch that is turned off and the first charge sharing switch connected to the precharge switch that is turned on are set to be turned on. LED driver.

8. In claim 7, The above switch controller When any one of the above precharge switches is turned on, the first charge sharing switch connected to the turned-off scan switch and the first charge sharing switch connected to the turned-on precharge switch are set to be turned off. LED driver.

9. In claim 1, Each of the above multiple channel units Further comprising a second charge sharing switch for moving the charge of the second capacitors forming the electrostatic capacitance between each of the plurality of LEDs and each of the channel current sources to any one of the plurality of first capacitors, The above switch controller Further controlling the above second charge sharing switches LED driver.

10. In claim 9, The above switch controller All of the second charge sharing switches are set to be turned on at the time when at least one of the first charge sharing switches is turned on. LED driver.

11. In claim 10, The above switch controller All of the second charge sharing switches are set to be turned off at the time when at least one of the first charge sharing switches is turned off. LED driver.

12. In claim 11, One end of each of the second charge sharing switches is connected to each of the second capacitors, and the other end of each of the second charge sharing switches is connected to each of the first charge sharing switches. LED driver.

13. In claim 1, The above multiple scandals A first scan stage including a first scan switch and a first-first charge sharing switch; and After the scan operation of the first scan stage is performed, a scan operation is performed, and a second scan stage including a second scan switch and a first-second charge sharing switch is included. The above plurality of first capacitors It includes a first capacitor connected to the first charge sharing switch and a first capacitor connected to the first charge sharing switch, The above switch controller The first scan switch is set to turn on the first-1 charge sharing switch and the first-2 charge sharing switch at the time when the first scan switch is turned off. LED driver.

14. In claim 13, The above LED driver Further comprising a voltage generator for supplying a precharge voltage to the plurality of first capacitors, The first scan stage further includes a first precharge switch for precharging the first-1 capacitor, and the second scan stage further includes a second precharge switch for precharging the first-2 capacitor. The above switch controller The first precharge switch is set to turn off the first-1 charge sharing switch and the first-2 charge sharing switch at the time when the first precharge switch is turned on. LED driver.

15. In claim 14, Each of the above multiple channel units Further comprising a second charge sharing switch for moving the charge of each of the plurality of second capacitors forming electrostatic capacitance between each of the plurality of LEDs and each of the channel current sources to any one of the plurality of first capacitors, The above switch controller All of the second charge sharing switches are turned on at a time when the first-first charge sharing switch and the first-second charge sharing switch are set to be turned on, and all of the second charge sharing switches are turned off at a time when the first-first charge sharing switch and the first-second charge sharing switch are set to be turned off. LED driver.

16. A display panel comprising a plurality of LEDs; An LED driver including a plurality of scan stages, each scan stage being connected to the plurality of LEDs and including a plurality of channel stages including a channel current source, a scan switch connected to the plurality of LEDs and for a scan operation, and a first charge sharing switch for transferring the charge of one of the plurality of first capacitors forming a capacitance between the plurality of LEDs and the scan switch to another capacitor; and A switch controller comprising a switch controller that controls the first charge sharing switches. Display device.

17. In claim 16, The above LED driver Further comprising a voltage generator for supplying a precharge voltage to the first capacitors, Each of the plurality of scan stages further includes a precharge switch for precharging one of the plurality of first capacitors, The above switch controller Set to control the first charge sharing switches based on the operation of at least one of the scan switches and the precharge switches. Display device.

18. In claim 17, The above switch controller When at least one of the scan switches is turned off, the first charge sharing switch connected to the scan switch to be turned off and the first charge sharing switch connected to the precharge switch to be turned on are turned on, The first charge sharing switches are set to be turned off when any one of the above precharge switches is turned on. Display device.

19. In claim 18, Each of the above multiple channel units Further comprising a second charge sharing switch for moving the charge of each of the second capacitors forming electrostatic capacitance between each of the plurality of LEDs and each of the channel current sources to any one of the plurality of first capacitors, The above switch controller It is set to further control the above second charge sharing switches. Display device.

20. In claim 19, The above switch controller All of the second charge sharing switches are set to be turned on while at least some of the first charge sharing switches are turned on. Display device.

Images