Display driver

Abstract

This disclosure discloses a display driver device in which the power consumption of a chip is optimized by controlling each output channel of the chip. The display driver device includes a current consumption control circuit for each output channel. The current consumption control circuit is configured to selectively provide a control current with a high current quantity to drive the output voltage at the output terminal of an output buffer in response to a pattern variation having a large difference between the input voltage and the output voltage.

Description

Technical Field

[0001] This disclosure relates to a display driver, and more specifically, to a display driver that optimizes the power consumption of a chip by controlling each output channel of the chip. Background Technology

[0002] The display device includes a display panel, such as an LCD panel or an LED panel, for displaying a screen, and a display driver for driving the display panel.

[0003] In the display panel and the display driver, the display driver is manufactured as a chip (i.e., an integrated circuit) and configured to process display data provided from the outside and to provide an output voltage corresponding to the display data to the display panel. The display panel can display a screen using the output voltage of the display driver.

[0004] Typically, in the case of high-resolution gaming laptops, display drivers need to be developed using low-power drive technology.

[0005] Low-power drive technology is implemented to control power consumption within the chip unit. In this case, the power consumption of the display driver is set within the chip unit. Therefore, it is difficult to configure the display driver to have optimized current consumption for each output channel.

[0006] In addition, the display driver of a gaming laptop needs to be configured to have high current consumption in order to improve the switching rate during driving.

[0007] If the display driver is configured to have high current consumption in the chip unit, the power consumption of a gaming laptop may increase significantly.

[0008] Therefore, display drivers need to be designed to optimize the current consumption of each output channel according to the display pattern in order to effectively reduce power consumption. Summary of the Invention

[0009] Various embodiments relate to providing a display driver that can optimize the current consumption of each output channel and perform low-power driving on each output channel.

[0010] Furthermore, various embodiments relate to providing a display driving device capable of selectively performing low-power driving by determining the output variation of each output channel, thereby controlling the drive current of each output channel according to the driving mode.

[0011] In one embodiment, the display driving device may include: a plurality of output buffers configured to form output channels and each outputting an output voltage corresponding to the input voltage; and a plurality of current consumption control circuits configured for the respective output channels. When the difference between the input voltage and the output voltage is equal to or greater than a preset reference value, each of the current consumption control circuits provides a control current to the output terminal of the corresponding output buffer.

[0012] In an embodiment, the display driving device may include: an output buffer configured to form an output channel and output an output voltage corresponding to an input voltage; a current control unit configured to provide a control signal corresponding to the difference between the input voltage and the output voltage; and a current setting unit configured to provide a control current to the output terminal of the output buffer in response to a control signal when the difference is equal to or greater than a preset reference value.

[0013] The display driver disclosed herein can reduce power consumption in a chip cell because it can perform low-power driving for each output channel, which consists of an output buffer.

[0014] Furthermore, the display driver of this disclosure can control the drive current of each output channel according to the drive mode, and perform a low-power drive with optimized current consumption for each output channel.

[0015] Furthermore, the display driver of this disclosure can control the drive current of each output channel by determining the difference between the input voltage and the output voltage, and has optimized current consumption for each output channel of the chip. Attached Figure Description

[0016] Figure 1 This is a block diagram illustrating a display driving device that implements the present disclosure.

[0017] Figure 2 This is a block diagram illustrating a display driving device according to a preferred embodiment of the present disclosure.

[0018] Figure 3 It is shown Figure 2 Block diagram of the current consumption control circuit.

[0019] Figure 4 and Figure 5 It is shown Figure 2 A block diagram showing the state of the output control current of the current consumption control circuit.

[0020] Figure 6 This is a flowchart describing the low-power drive for each output channel. Detailed Implementation

[0021] The display driver disclosed herein is configured to provide an output voltage to a display panel (not shown) used for a display screen.

[0022] For this purpose, the display driver is manufactured as an integrated circuit and has multiple output channels for outputting output voltages. The display driver receives display data from an external source (e.g., a timing controller) and outputs an output voltage corresponding to the display data through the multiple output channels.

[0023] Figure 1 An example is shown where the display driver 100 has multiple output channels 10, 12, etc.

[0024] like Figure 1 As shown, the display driver 100 may include multiple output channels 10, 12, etc., for outputting output voltages corresponding to the display data.

[0025] exist Figure 1 As can be understood, output channels 10, 12, etc. have the same structure. Therefore, as a representative example, the detailed configuration of output channels 10, 12, etc. will be described with reference to output channel 10, and redundant diagrams and descriptions of the output channels will be omitted.

[0026] The display driver 100 is configured to output the display data corresponding to the output voltage Vout through each of the output channels 10, 12, etc.

[0027] For this purpose, each of the output channels 10, 12, etc. may include a digital-to-analog converter (DAC) 20 and an output buffer 22.

[0028] The display driving device 100 may include a digital processing unit for receiving and processing display data. Specifically, the display driving device 100 may include a latch unit (not shown) and a level shifter (not shown). The latch unit is used to arrange the display data received in series in parallel, and the level shifter is used to shift the levels of the arranged display data and provide the level-shifted display data to the DAC 20. However, for the sake of describing embodiments of this disclosure, from... Figure 1 The components used for digital processing are omitted.

[0029] DAC 20 is configured to receive display data corresponding to output channel 10, select an analog voltage corresponding to the display data, and output the selected analog voltage. More specifically, DAC 20 can be configured to receive multiple gamma voltages (not shown), select a gamma voltage corresponding to the display data, and output the selected gamma voltage as an analog voltage.

[0030] In this case, the analog voltage output by DAC 20 corresponds to the input voltage of the output buffer 22, which will be described later, and is denoted as the input voltage Vin.

[0031] Output buffer 22 is configured to output an output voltage Vout corresponding to the input voltage Vin. Output buffer 22 is configured for each of the output channels 10, 12, etc. Therefore, it can be understood that the display driver 100 includes an output buffer for each output channel and outputs multiple output voltages Vout through multiple output channels.

[0032] More specifically, output buffer 22 receives an input voltage Vin and a feedback output voltage Vout. For example, the input voltage Vin can be input to the positive input stage (not shown) of output buffer 22. The feedback output voltage Vout can be input to the negative input stage (not shown) of output buffer 22.

[0033] The output buffer 22 is configured to internally generate a drive current corresponding to the input voltage Vin and the feedback output voltage Vout, and output an output voltage Vout corresponding to the drive current.

[0034] The display driver disclosed herein can be as follows: Figure 2 The implementation shown optimizes current consumption for each output channel and performs low-power drive. Figure 2 The diagram shows a current consumption control circuit 24. Figure 2 In the middle, DAC 20 and output buffer 22 have the same Figure 1 The DAC 20 and output buffer 22 have the same configuration, and are in line with... Figure 1 The DAC 20 and output buffer 22 operate in the same way, so their redundant description is omitted.

[0035] The current consumption control circuit 24 is configured for each of the output channels 10, 12, etc.

[0036] The current consumption control circuit 24 is configured to provide a control current Ic to the output terminal of the output buffer 22 when the difference between the input voltage Vin and the output voltage Vout is equal to or greater than a preset reference value.

[0037] When the output voltage Vout changes significantly in consecutive horizontal periods N and (N-1)th periods, it can be determined that the output voltage Vout of a specific pixel on the display panel has changed to represent a dynamic pattern with significant brightness variations. Furthermore, when the output voltage Vout changes only slightly in consecutive horizontal periods N and (N-1)th periods, it can be determined that the output voltage Vout of a specific pixel on the display panel has changed to represent a static pattern with small brightness variations. It can be understood that N is a natural number, and the output voltage Vout in the Nth horizontal period corresponds to the input voltage Vin in the current horizontal period. It can be understood that the output voltage Vout in the (N-1)th horizontal period corresponds to the input voltage Vin in the previous horizontal period.

[0038] It is understandable that the reference value is a preset value used to distinguish between static and dynamic patterns. The reference value can be set as the absolute value of the difference between the preset input voltage Vin and the output voltage Vout.

[0039] The current consumption control circuit 24 is configured to not provide control current Ic to the output terminal of the output buffer 22 in the first case where the difference between the input voltage Vin and the output voltage Vout is less than a reference value, and to provide control current Ic to drive the output voltage Vout in the second case where the difference between the input voltage Vin and the output voltage Vout is equal to or greater than the reference value.

[0040] In this case, preferably, a control current Ic is provided that has an absolute value higher than the drive current of the output buffer 22.

[0041] Therefore, the current consumption control circuit 24 can be configured to include a current control unit 30 and a current setting unit 32.

[0042] The current control unit 30 is configured to provide a control signal DL corresponding to the difference between the input voltage Vin and the output voltage Vout.

[0043] Furthermore, the current setting unit 32 includes a positive current source IR and a negative current source IF. The current setting unit 32 is configured to not provide a control current Ic in response to a control signal DL when the difference between the input voltage Vin and the output voltage Vout is less than a reference value, and to provide a control current Ic from the positive current source IR or the negative current source IF to the output terminal of the output buffer 22 in response to a control signal DL when the difference between the input voltage Vin and the output voltage Vout is equal to or greater than the reference value.

[0044] refer to Figures 3 to 5 The specific implementation of the current consumption control circuit 24 is described. Figure 3The current-consuming control circuit 24 is shown, and the state in which the positive switch Sp and the negative switch Sn are turned off and the control current Ic is not provided to the output of the output buffer 22 is shown. Figure 4 It shows Figure 3 The current consumption control circuit 24 provides a control current Icn with a negative component by turning on the negative switch Sn. Figure 5 It shows Figure 3 The current-consuming control circuit 24 provides a control current Icp with a positive component by turning on the positive switch Sp. Figure 4 and Figure 5 In this context, control currents Icn and Icp are used to distinguish between positive and negative components. In the following description, control current Ic is used as... Figure 4 and Figure 5 The term refers to the control currents Icn and Icp in the system.

[0045] First, the current control unit 30 is configured to include a comparator 40 and control logic 42.

[0046] Comparator 40 is configured to compare the input voltage Vin and the feedback output voltage Vout, and output a comparison signal dV corresponding to the difference between the input voltage Vin and the feedback output voltage Vout. Comparator 40 may be configured to include a comparator amplifier, which is configured to output the comparison signal dV corresponding to the difference between the input voltage Vin and the feedback output voltage Vout, or a comparison signal dV with a high level, when the difference between the input voltage Vin and the feedback output voltage Vout is equal to or greater than an internal bias voltage.

[0047] Control logic 42 can be configured to receive a comparison signal dV and provide control signals DL with different levels when the difference between the input voltage Vin and the feedback output voltage Vout is less than a reference value and when the difference is equal to or greater than the reference value. In this case, the reference value can be defined by an internal reference voltage. Furthermore, the control signal DL can be output as high when the level of the comparison signal dV is higher than the reference voltage and as low when the level of the comparison signal dV is lower than the reference voltage.

[0048] By configuring the current control unit 30, when the difference between the input voltage Vin and the feedback output voltage Vout is small, the comparator 40 can output a low-level comparison signal dV, and the control logic 42 can output a low-level control signal DL. Conversely, when the difference between the input voltage Vin and the feedback output voltage Vout is large, the comparator 40 can output a high-level comparison signal dV, and the control logic 42 can output a high-level control signal DL.

[0049] The current setting unit 32 can determine the difference between the input voltage Vin and the feedback output voltage Vout in response to the control signal DL. When the difference between the input voltage Vin and the feedback output voltage Vout is less than a reference value, the current setting unit 32, in response to the control signal DL, prevents the control current Ic from being supplied from the positive current source IR and the negative current source IF to the output terminal of the output buffer 22. Furthermore, when the difference between the input voltage Vin and the feedback output voltage Vout is equal to or greater than the reference value, the current setting unit 32, in response to the control signal DL, supplies the control current Ic from either the positive current source IR or the negative current source IF to the output terminal of the output buffer 22. In this case, the absolute value of the control current Ic can be significantly higher than the absolute value of the drive current of the output buffer 22.

[0050] Therefore, the current setting unit 32 includes a positive current circuit 32P and a negative current circuit 32N. The positive current circuit 32P includes a positive current source IR and a positive switch Sp. The negative current circuit 32N includes a negative current source IF and a negative switch Sn.

[0051] The positive current source IR is used to provide a control current Icp that corresponds to the driving voltage PVDD and has a positive component. The negative current source IF is used to provide a control current Icn that corresponds to the ground voltage GND and has a negative component.

[0052] Furthermore, the positive switch Sp is configured to switch the connection between the positive current source IR and the output terminal of the output buffer 22 in response to the control signal DL. The negative switch Sn is configured to switch the connection between the negative current source IF and the output terminal of the output buffer 22 in response to the control signal DL. In this case, it can be understood that the output terminal of the output buffer 22 refers to the node connected to the output stage of the output channel.

[0053] With this configuration, when the positive switch Sp or the negative switch Sn is turned on in response to the control signal DL, the current setting unit 32 can provide a control current Ic to the output terminal of the output buffer 22.

[0054] It is understood that the current setting unit 32 uses the drive voltage PVDD and the ground voltage GND, and the potential difference between the drive voltage PVDD and the ground voltage GND is greater than the potential difference between the operating voltage provided for the operation of the output buffer 22 and the ground voltage. Therefore, it is understood that the current setting unit 32 is an additional circuit that provides a control current Ic with a high current quantity to the output terminal of the output buffer 22 to drive the output voltage Vout when activated in response to the control signal DL.

[0055] When driven by a high-current control current Ic added by the current setting unit 32, the output voltage Vout can rise rapidly during its rise and fall rapidly during its fall. That is, the output voltage Vout can have an improved slew rate to drive gaming laptops and the like with high current consumption.

[0056] like Figure 3 As shown, in the case of a static pattern where the pattern of output channel 10 does not change much, the positive switch Sp and the negative switch Sn are open. At this time, because the control current Ic of the current setting unit 32 is not provided to output channel 10, output channel 10 can output an output voltage Vout with low current consumption, and drive the output voltage Vout through output buffer 22.

[0057] like Figure 4 or Figure 5 As shown, in the case of a dynamic pattern with large pattern changes in the output channel 10, either the positive switch Sp or the negative switch Sn is turned on. At this time, because the output channel 10 drives the output voltage Vout while providing the control current Ic from the current setting unit 32, the output channel 10 can output an output voltage Vout with high current consumption. In this case, the output voltage Vout can have an improved slew rate.

[0058] In embodiments of this disclosure, the display driver 100 is configured to drive the output voltage Vout for the corresponding output channel only in the case of dynamic patterns with large pattern changes, by switching the positive switch Sp and the negative switch Sn, wherein each output channel has an output buffer configured therein. In the case of static patterns with small pattern changes, the display driver 100 drives the output voltage Vout for each output channel with a small current. Therefore, in embodiments of this disclosure, the display driver 100 can reduce power consumption in the chip cell because it selectively drives the output voltage Vout with a large current only for the required output channels.

[0059] Furthermore, in embodiments of this disclosure, by changing the switching states of the positive switch Sp and the negative switch Sn according to the driving mode, the display driving device 100 can control the driving current of each output channel and has optimized current consumption for each output channel.

[0060] Furthermore, in embodiments of this disclosure, by determining the difference between the input voltage Vin and the output voltage Vout corresponding to a change in the driving mode, the display driving device 100 can control the driving current of each output channel and has optimized current consumption for each output channel of the chip.

[0061] In embodiments of this disclosure, with Figures 3 to 5Depending on the implementation, the display driver 100 can be configured to control the activation and deactivation of the positive current source IR and the negative current source IF in response to the control signal DL. In this case, the display driver 100 includes a positive current source IR whose current supply is controlled in response to the control signal DL and a negative current source IF whose current supply is controlled in response to the control signal DL. The display driver 100 can provide a control current Ic to the output terminal of the output buffer 22 through the positive current source IR or the negative current source IF, which is activated in response to the control signal DL.

[0062] like Figures 1 to 5 The display driver implemented in this disclosure uses... Figure 6 The method controls the drive current of the output buffer 22 based on the settings of each channel.

[0063] That is, comparator 40 compares the input voltage Vin and the output voltage Vout of each output channel (S10). In this case, the difference dV between the input voltage Vin and the output voltage Vout can be expressed as an absolute value. The absolute value can be represented by the equation dV = |Vout - Vin|.

[0064] When the difference dV between the input voltage Vin and the output voltage Vout is less than the reference value Vth, the output channel of the display driver 100 can perform a low-power mode operation (S20) corresponding to the static pattern, and then perform static power saving (S30). It can be understood that the low-power mode operation (S20) is similar to... Figure 3 The control current Ic shown corresponds to the situation where the positive current source IR and the negative current source IF are blocked from being supplied to the output terminal of the output buffer 22, and it is an operation to reduce current consumption.

[0065] When the difference dV between the input voltage Vin and the output voltage Vout is equal to or greater than the reference value Vth, the output channel of the display driver 100 can perform a dynamic mode operation (S22) corresponding to the dynamic pattern, and then perform adaptive fast setting (S32). It can be understood that the dynamic mode operation (S22) is similar to... Figure 4 and Figure 5 The control current Ic shown corresponds to the case where the positive current source IR or the negative current source IF is provided to the output terminal of the output buffer 22, and is an operation such as pre-charging setting to drive the output voltage Vout with high current consumption.

[0066] As described above, the display driver of this disclosure can be configured to reduce power consumption in the chip cell and has power consumption optimized for each output channel, since low-power driving can be selectively controlled for each output channel.

[0067] Furthermore, the display driving device of this disclosure can control the drive current of each output channel by determining the pattern change (i.e., the difference between the input voltage and the output voltage).

[0068] Therefore, the display driver of this disclosure can set the power consumption for each output channel to have high current consumption, thereby improving the conversion rate while having optimized current consumption for each output channel.

[0069] Therefore, the display driver can reduce the power consumption in the chip unit by setting the power consumption of each output channel.

Claims

1. A display driving apparatus comprising: a plurality of output buffers configured to form output channels and to output output voltages corresponding to input voltages, respectively; and a plurality of consumption current control circuits configured for respective ones of the output channels, wherein each of the consumption current control circuits provides a control current to an output terminal of a respective output buffer when a difference between the input voltage and the output voltage is equal to or greater than a preset reference value, wherein the consumption current control circuit comprises: a current control unit configured to provide a control signal corresponding to the difference; and a current setting unit including a positive current source and a negative current source and configured to provide the control current from the positive current source or the negative current source to the output terminal of the output buffer in response to the control signal when the difference is equal to or greater than the reference value, wherein the current control unit comprises: a comparator configured to output a comparison signal corresponding to the difference; and a control logic configured to receive the comparison signal and to provide the control signal having different levels according to a case where the difference is less than the reference value and a case where the difference is equal to or greater than the reference value, wherein the positive current source provides a control current corresponding to a positive component of a driving voltage, and the driving voltage is greater than an operating voltage provided for operation of the output buffer.

2. The display driving device according to claim 1, wherein the current setting unit prevents the control current from being provided from the positive current source and the negative current source to the output terminal of the output buffer in response to the control signal when the difference is less than the reference value; and provides the control current from the positive current source or the negative current source to the output terminal of the output buffer in response to the control signal when the difference is equal to or greater than the reference value. the current setting unit comprises:

3. The display driving device according to claim 1, wherein the positive current source; a positive switch configured to switch coupling between the positive current source and the output terminal of the output buffer in response to the control signal; the negative current source; and a negative switch configured to switch coupling between the negative current source and the output terminal of the output buffer in response to the control signal, and wherein the current setting unit provides the control current to the output terminal of the output buffer through the positive switch turned on or the negative switch turned on in response to the control signal. 4.A display driving apparatus comprising: an output buffer configured to form an output channel and to output an output voltage corresponding to an input voltage; a current control unit configured to provide a control signal corresponding to a difference between the input voltage and the output voltage; and a current setting unit configured to provide a control current to an output terminal of the output buffer in response to the control signal when the difference is equal to or greater than a preset reference value, wherein the current control unit comprises: a comparator configured to output a comparison signal corresponding to the difference; and a control logic configured to receive the comparison signal and to provide the control signal having different levels according to a case where the difference is less than the reference value and a case where the difference is equal to or greater than the reference value. ​ control logic configured to receive the comparison signal and provide the control signal having different levels according to a case where the difference value is smaller than the reference value and a case where the difference value is equal to or larger than the reference value, wherein the current setting unit includes a positive current source and a negative current source, and in response to the control signal, provides the control current to the output terminal of the output buffer from the positive current source or the negative current source, wherein the positive current source provides a control current corresponding to a positive part of a driving voltage, and the driving voltage is larger than an operating voltage provided for operation of the output buffer.

5. The display driving device according to claim 4, wherein the current setting unit in response to the control signal when the difference value is smaller than the reference value, blocks the control current from being provided to the output terminal of the output buffer from the positive current source and the negative current source; and and in response to the control signal when the difference value is equal to or larger than the reference value, provides the control current to the output terminal of the output buffer from the positive current source or the negative current source.

6. The display driving device according to claim 5, wherein the current setting unit includes: the positive current source; a positive switch configured to switch coupling between the positive current source and the output terminal of the output buffer in response to the control signal; the negative current source; and a negative switch configured to switch coupling between the negative current source and the output terminal of the output buffer in response to the control signal, and wherein the current setting unit provides the control current to the output terminal of the output buffer through the turned-on positive switch or the turned-on negative switch in response to the control signal.

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