KR102586459B1 - Source driver for display apparatus - Google Patents

Abstract

The present invention discloses a source driver for a display device that drives a display panel using display data and senses pixel signals of the display panel. The source driver uses a buffer to control the reference voltage and the pixels of the display panel during the sensing period. Provides the pixel sensing signal by comparing the signals, and includes a sensor and an ADC that drive the source signal during a driving period using the buffer and output it to the display panel, and drive the display panel.

Description

Source driver for display device {SOURCE DRIVER FOR DISPLAY APPARATUS}

The present invention relates to a source driver, and more specifically, to a source driver of a display device that drives a display panel using display data and senses pixel signals of the display panel.

A flat panel display device includes a source driver that provides source signals for display on a display panel. The source driver is configured to convert display data provided from an external source such as a timing controller into a source signal and provide the source signal to the display panel.

The display panel may be composed of a liquid crystal display panel (LCD panel) or a light-emitting diode panel (LED panel). Among these, the LCD panel displays the screen by the optical shutter action of liquid crystal for each pixel, and the LED panel displays the screen for each pixel. The screen is displayed by controlling the light emission of the light emitting diode.

Among these, the source driver for the LED panel is configured to sense the characteristics of the pixels of the LED panel. When the source driver provides sensing data corresponding to pixel characteristics, the timing controller or application processor performs display data correction using the sensing data. As a result, the source driver drives the display panel using the corrected display data, so that the image of the display panel can be expressed in a good state with reduced influence on pixel characteristics.

For this purpose, the source driver includes a sensor that outputs a sensing signal for pixel characteristics and an analog-to-digital converter (ADC) that judges the sensing signal and outputs sensing data. In the source driver, the analog-to-digital converter is configured separately from the source driving module that processes display data. The source driving module includes analog circuits that generate source signals corresponding to display data.

The source driving module, sensor, and analog-to-digital converter are each configured for each channel of the source driver that outputs the source signal to the display panel. The source driver provides source signals to the display panel and receives pixel signals through a large number of channels. Therefore, a source driver manufactured as an integrated circuit includes a large number of sensors corresponding to the number of channels.

Since the sensors are each configured for each channel of the source driver, they occupy a large area within the source driver. Therefore, sensors become a factor that increases the area of the source driver manufactured as an integrated circuit.

Additionally, since the sensor occupies a large portion of the limited IC area, it is difficult to efficiently design the internal circuit of the source driver.

The purpose of the present invention is to provide a display that can reduce the area required for design and efficiently design the internal circuit by using a single buffer to output the source signal of the source driving module to the display panel or receive the pixel signal of the display panel. It provides source drivers for devices.

Another object of the present invention is to reduce the area required for design and efficiently design the internal circuit by using a single buffer to output the source signal of the source driving module to the display panel or to sense the pixel signal of the display panel. It provides source drivers for display devices.

The source driver of the display device of the present invention includes a source driving module that generates a source signal corresponding to display data; A conversion module that generates sensing data corresponding to the pixel sensing signal; and a buffer, providing the pixel sensing signal by comparing a reference voltage and a pixel signal of the display panel in a sensing period using the buffer, and driving the source signal in a driving period using the buffer to control the display panel. It is characterized by having a complex buffer circuit that outputs to.

In addition, the source driver of the display device of the present invention includes a buffer having a first input terminal, a second input terminal, and an output terminal that outputs a source signal or a pixel sensing signal; a first selection circuit that provides a reference voltage to the first input terminal during a sensing period and provides the source signal output corresponding to display data from a digital-to-analog converter to the first input terminal during a driving period; a second selection circuit that provides a pixel signal of the display panel to the second input terminal during the sensing period and forms a feedback path between the output terminal and the first input terminal during the driving period; an analog-to-digital converter that receives the pixel sensing signal from the output terminal and performs analog-to-digital conversion on the pixel sensing signal to generate sensing data; and a third selection circuit that transmits the pixel sensing signal of the output terminal to the analog-to-digital converter in the sensing period and transmits the source signal of the output terminal to the display panel in the driving period. .

In addition, the source driver of the display device of the present invention includes a buffer having a first input terminal, a second input terminal, and an output terminal that outputs a source signal or a pixel sensing signal; a first selection circuit that provides a reference voltage to the first input terminal during a sensing period and provides the source signal output corresponding to display data from a digital-to-analog converter to the first input terminal during a driving period; a second selection circuit that provides a pixel signal of the display panel to the second input terminal during the sensing period and forms a feedback path between the output terminal and the first input terminal during the driving period; a sensor that receives the pixel sensing signal from the output terminal, senses the pixel sensing signal, and provides a sensing signal for conversion into sensing data; and a third selection circuit that transmits the pixel sensing signal of the output terminal to the sensor during the sensing period and transmits the source signal of the output terminal to the display panel during the driving period.

The present invention is configured so that one buffer is used to output a source signal to the display panel in the driving period or to receive or sense a pixel signal in the sensing period. Therefore, the present invention can reduce the area required for designing the configuration of the source driving module and sensor for each channel, and can efficiently design the internal circuit of the source driver.

1 is a diagram illustrating a state in which a source driver of a display device of the present invention is connected to a display panel.
Figure 2 is a block diagram illustrating an embodiment of the source driver of the display device of the present invention.
Figure 3 is a detailed block diagram of the source driver of Figure 2;
FIG. 4 is a waveform diagram for explaining the switching operation of the source driver of FIG. 2.
Figure 5 is a detailed block diagram of another example of the source driver of Figure 2;

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Terms used in this specification and patent claims should not be construed as limited to their usual or dictionary meanings, but should be construed with meanings and concepts consistent with the technical details of the present invention.

The embodiments described in this specification and the configurations shown in the drawings are preferred embodiments of the present invention, and do not represent the entire technical idea of the present invention, so various equivalents and modifications that can replace them at the time of filing the present application are available. There may be.

The present invention discloses a source driver for a flat panel display device.

The source driver of the present invention has the function of transmitting sensing data converted from the pixel signal of a display panel such as an LED panel that needs to sense pixel characteristics to a timing controller (not shown) or an application processor (not shown). An example having the following is disclosed.

Referring to FIG. 1, the display device includes a source driver 100 and a display panel 200, and is configured to output source signals from the source driver 100 to the display panel 200, and output sensing signals to the display panel (200). 200) is configured to output to the source driver 100.

The source driver 100 is configured to restore display data provided from an external source (not shown) such as a timing controller, and generate and output a source signal using the restored display data. Source signals are output through multiple channels of the source driver 100.

Additionally, the source driver 100 receives the sensing signal from the display panel 200 through each channel, samples the sensing signal, converts it into sensing data, which is a digital signal, and provides the sensing data to a timing controller or application processor. It is composed.

The sensing data can be used to correct display data to be provided to the source driver 100, and the source driver 100 receives the corrected display data and provides it to the display panel 200 in good condition without affecting the characteristics of the display panel. Images can be driven.

Referring to FIG. 2 , the source driver 100 may include a source driving module 102, a complex buffer circuit 104, a conversion module 106, and a gamma circuit 108.

The source driver 100 may be designed so that a source driving module 102, a complex buffer circuit 104, and a conversion module 106 are disposed on both sides of the gamma circuit 108.

The source driving module 102 restores display data and generates a source signal using the restored display data.

The conversion module 106 generates sensing data corresponding to the pixel sensing signal.

The composite buffer circuit 104 includes a buffer 40 described later. The complex buffer circuit 104 provides a pixel sensing signal that compares the reference voltage and the pixel signal of the display panel 200 during the sensing period to the conversion module 106 using the buffer 40. It is configured to drive the source signal of the source driving module 102 and output it to the display panel 200 during the driving period.

The gamma circuit 108 is configured to provide gamma voltages to the source driving module 102, and the source driving module 102 can generate a source signal by selecting a gamma voltage corresponding to display data.

The detailed configuration of the above-described source driving module 102, complex buffer circuit 104, and conversion module 106 will be described with reference to FIG. 3.

The source driving module 102, the complex buffer circuit 104, and the conversion module 106 are each configured for each channel of the source driver 100 that outputs the source signal. That is, a source driving module 102 and a complex buffer circuit 104 may be configured for each channel to output the source signal of the source driver 100, and a conversion module 106 and a complex buffer may be configured for each channel receiving the sensing signal. Circuit 104 may be configured. The complex buffer circuit 104 may be configured to output a source signal or receive a sensing signal through the same channel.

The source driving module 102 includes a latch 20, a level shifter 22, and a digital-to-analog converter 24.

The latch 20 stores display data (DATA) including a plurality of bits input serially and is configured to perform latch to provide display data (DATA) in parallel. The latch 20 can be understood as consisting of a combination of flip-flops that sequentially latch multiple bits input in series and output multiple bits in parallel simultaneously in synchronization with an output enable signal (not shown). .

The level shifter 22 performs a level shift on the display data (DATA). That is, the level shifter 22 is used to adjust the level of each bit signal of the display data (DATA) stored in the latch 20 and output in parallel to meet the input specifications required by the digital analog converter 24.

The digital-analog converter 24 is configured to select a gamma voltage corresponding to the display data (DATA) provided from the level shifter 22 and output the selected gamma voltage as a source signal. That is, the digital-to-analog converter 24 generates a source signal corresponding to the display data (DATA).

The complex buffer circuit 104 includes a buffer 40 and switches SW1 to SW6.

The buffer 40 has a first input terminal, a second input terminal, and an output terminal that outputs a source signal or a pixel sensing signal.

A selection circuit for the first input terminal of the buffer 40 is configured by switches SW1 and SW2, and the switch SW1 selectively provides a reference voltage (Vref) to the first input terminal of the buffer 40, The switch SW2 selectively transmits the source signal of the digital-to-analog converter 24 of the source driving module 102 to the first input terminal of the buffer 40.

Additionally, a selection circuit for the second input terminal of the buffer 40 is configured by the switches SW3 and SW4, and the switch SW3 selectively forms a feedback path between the second input terminal and the output terminal of the buffer 40. And, the switch SW4 selectively provides the pixel signal of the display panel 200 to the second input terminal of the buffer 40.

In addition, a selection circuit for the output terminal of the buffer 40 is configured by switches SW5 and SW6, and the switch SW5 connects the output terminal of the buffer 40 and the display panel 200 to output the source signal OUT1. ) is selectively connected, and the switch SW6 selectively connects the output terminal of the buffer 40 and the conversion module 106 to output the pixel sensing signal OUT2.

In the above configuration, the switches SW4 and SW5 output the source signal OUT1 to the display panel 200 through the same channel (CH_P) of the source driver 100 and the pixel signal of the display panel 200. can receive.

The complex buffer circuit 104 may be controlled to turn on or turn off the switches SW1 to SW6 in response to the sensing period and the driving period as shown in FIG. 4. The switching of the switches SW1 to SW6 may be controlled, for example, by control signals of the display data DATA or control signals provided according to the data transmission status.

For example, the sensing period and the driving period may be periodically repeated alternately for one horizontal period of display data (DATA). One horizontal period can be divided into a blank period in which no display data exists and a display period in which one horizontal period of display data exists. Accordingly, the sensing period can be set to be included in the blank period, and the driving period can be set to correspond to the display period.

The switches SW1, SW4, and SW6 of the composite buffer circuit 104 may be turned on during the sensing period, and the switches SW2, SW3, and SW5 of the composite buffer circuit 104 may be turned on during the driving period.

When the switches SW1, SW4, and SW6 are turned on during the sensing period, the buffer 40 of the complex buffer circuit 104 is input to the second input terminal through the channel CH_P and the switch SW4. The pixel signal is compared with the reference voltage (Vref) input to the first input terminal through the switch (SW1) and the comparison result is provided as a pixel sensing signal (OUT2) to the conversion module 106 through the switch (SW6). . At this time, the pixel signal can be understood as a current, and the buffer 40 can act as a buffer for transmitting the pixel signal to the sensor 60, which will be described later, included in the sensor or conversion module 106 that senses the pixel signal. .

And, when the switches SW2, SW3, and SW5 are turned on during the driving period, the buffer 40 of the complex buffer circuit 104 is the source of the digital-to-analog converter 24 input to the first input terminal through the switch SW2. It is operated to drive the signal and output the source signal (OUT1) to the display panel 200 through the switch (SW5). At this time, the buffer 40 may act as an output buffer for the source driving module 102.

Meanwhile, the conversion module 106 may include a sensor 60 and an analog-to-digital converter 70.

The sensor 60 is configured to sense the pixel sensing signal OUT2 provided from the buffer 40 and provide a sensing signal SEN_O for conversion into sensing data.

To this end, the sensor 60 may include a transistor Q1 and a current sensor 62. The transistor Q1 may be configured to receive the pixel sensing signal OUT2 of the buffer 40 through a switch SW6 at its gate and control the current flow between the channel CH_P and the current sensor 62.

With the above configuration, the current sensor 62 senses the amount of current according to the operation of the transistor Q1 and outputs the sensing signal SEN_O. Exemplarily, the current sensor 62 may be configured to generate the sensing signal SEN_O by integrating or sampling the amount of current flowing through the transistor Q1.

The analog-to-digital converter 70 converts the sensing signal (SEN_O) into sample data (OUT3) and outputs it.

To this end, the analog-to-digital converter 70 is configured to include a comparator 72, a register 74, and a digital-to-analog converter 76. Here, the register 74 may be configured as a successive approximation register.

The comparator 72 provides the result of comparing the comparison sensing signal output from the digital-to-analog converter 76 and the sensing signal (SEN_O) provided from the current sensor 62 to the register 74 during the sensing period.

The register 74 stores the sensing data of the previous cycle, updates the sensing data by reflecting the comparison result of the comparator 72 to the sensing data, and outputs the updated sensing data (OUT3).

The digital-to-analog converter 76 receives the sensing data of the previous cycle from the register 74, converts it, and provides it to the comparator 72 as a comparison sensing signal.

By the above-described configuration, the comparator 72 can compare the sensing signal (SEN_O) of the current cycle with the comparison sensing signal of the previous cycle and provide a comparison result corresponding to the difference to the register 74. ) can output periodically updated sensing data (OUT3).

By the above configuration, the complex buffer circuit 104 has the function of an output buffer to provide the source signal OUT1 to the display panel 200 in response to the driving period and the pixel signal of the display panel 200 in response to the sensing period. The function of a buffer that provides a pixel sensing signal (OUT) for sensing in the sensor 60 can be performed in a complex manner.

Meanwhile, when the buffer 40 of the complex buffer circuit 104 is configured as a sensor, the pixel sensing signal OUT2 of the buffer 40 is provided as a sensing signal to the analog-to-digital converter 70 of the conversion module 106. The analog-to-digital converter 70 may perform analog-to-digital conversion on the pixel sensing signal OUT2 to generate sensing data OUT3.

Additionally, in an embodiment of the present invention, the sensor 60 may be configured as shown in FIG. 5.

The embodiment of FIG. 5 has a different configuration of the sensor 60 compared to the embodiment of FIG. 3 and the configuration of other components is the same. In the embodiment of FIG. 5, descriptions of the configuration and operation of the same components as those of FIG. 3 are omitted.

In the embodiment of Figure 5, sensor 60 may include transistor Q1, voltage sensor 64, and load circuit 66.

The transistor Q1 may be configured to receive the pixel sensing signal OUT2 of the buffer 40 through a switch SW6 at the gate and control the current flow between the channel CH_P and the load circuit 66.

The load circuit 66 may be configured as a constant current source, and the voltage sensor 64 may be configured to sense a change in voltage of the load circuit corresponding to the amount of current flowing through the transistor Q1.

With the above configuration, the voltage sensor 64 can generate the sensing signal (SEN_O) by sensing the voltage change of the load circuit 66 according to the operation of the transistor (Q1) corresponding to the pixel sensing signal (OUT2). .

In the above configuration, voltage sensor 64 may be configured as a comparator. When the voltage sensor 64 is configured as a comparator, the comparator may be configured to generate a sensing signal (SEN_O) as a result of comparing the reference voltage of the load circuit 66 with the voltage change of the load circuit 66.

As described above, embodiments of the present invention have a configuration in which the buffer 40 is commonly used for driving the source signal of the source driving module 102 and sensing the pixel signal of the display panel 200.

In other words, the present invention is designed to design the configuration of the source driving module and sensor for each channel as one buffer is used to output the source signal to the display panel in the driving period or to receive or sense the pixel signal in the sensing period. The area required can be reduced and the internal circuit of the source driver can be designed efficiently.

Claims (16)

a source driving module that generates a source signal corresponding to display data;
A conversion module that generates sensing data corresponding to the pixel sensing signal; and
It includes a buffer, and provides the pixel sensing signal by comparing a reference voltage and a pixel signal of the display panel in a sensing period using the buffer, and drives the source signal in a driving period using the buffer to provide a signal to the display panel. It has a complex buffer circuit that outputs,
The complex buffer circuit is,
a buffer having a first input terminal, a second input terminal, and an output terminal for outputting the source signal or the pixel sensing signal;
a first switch that selectively provides the reference voltage to the first input terminal;
a second switch that selectively transmits the source signal of the source driving module to the first input terminal;
a third switch that selectively forms a feedback path between the second input terminal and the output terminal;
a fourth switch selectively providing the pixel signal to the second input terminal;
a fifth switch selectively connecting the output terminal and the display panel; and
A sixth switch selectively connecting the output terminal and the conversion module. delete According to claim 1,
The complex buffer circuit is a source of a display device that turns on the first switch, the fourth switch, and the sixth switch in the sensing period and turns on the second switch, the third switch, and the fifth switch in the driving period. driver. According to claim 1,
The conversion module includes an analog-to-digital converter, and generates sensing data by performing analog-to-digital conversion on the pixel sensing signal provided during the sensing period. According to claim 1,
The conversion module includes a sensor,
The sensor is a source driver of a display device that senses the pixel sensing signal provided from the buffer and provides a sensing signal for conversion into the sensing data. The method of claim 5, wherein the sensor:
A transistor driven by the pixel sensing signal; and
A current sensor that senses the amount of current according to the operation of the transistor and provides the sensing signal. The method of claim 5, wherein the sensor:
A transistor driven by the pixel sensing signal;
a load circuit to which a voltage corresponding to the amount of current according to the operation of the transistor is applied; and
A source driver for a display device comprising: a voltage sensor providing the sensing signal corresponding to the voltage of the load circuit. According to clause 7,
The voltage sensor is a source driver of a display device configured as a comparator. According to clause 7,
The source driver of a display device, wherein the complex buffer circuit outputs the source signal to the display panel and receives the pixel signal of the display panel through the same channel. A buffer having a first input terminal, a second input terminal, and an output terminal for outputting a source signal or a pixel sensing signal;
a first selection circuit that provides a reference voltage to the first input terminal during a sensing period and provides the source signal output corresponding to display data from a digital-to-analog converter to the first input terminal during a driving period;
a second selection circuit that provides a pixel signal of the display panel to the second input terminal during the sensing period and forms a feedback path between the output terminal and the second input terminal during the driving period;
an analog-to-digital converter that receives the pixel sensing signal from the output terminal and performs analog-to-digital conversion on the pixel sensing signal to generate sensing data; and
A third selection circuit that transmits the pixel sensing signal of the output terminal to the analog-to-digital converter in the sensing period and transmits the source signal of the output terminal to the display panel in the driving period,
The first selection circuit includes a first switch for providing the reference voltage to the first input terminal in the sensing period and a second switch for transmitting the source signal to the first input terminal in the driving period,
The second selection circuit includes a third switch that forms a feedback path between the second input terminal and the output terminal in the driving period and a fourth switch that provides the pixel signal to the second input terminal in the sensing period, and,
The third selection circuit includes a fifth switch that transmits the source signal of the output terminal to the display panel in the driving period and a sixth switch that transmits the pixel sensing signal of the output terminal to the analog-to-digital converter in the sensing period; Source driver for the display device, including . delete A buffer having a first input terminal, a second input terminal, and an output terminal for outputting a source signal or a pixel sensing signal;
a first selection circuit that provides a reference voltage to the first input terminal during a sensing period and provides the source signal output corresponding to display data from a digital-to-analog converter to the first input terminal during a driving period;
a second selection circuit that provides a pixel signal of the display panel to the second input terminal during the sensing period and forms a feedback path between the output terminal and the second input terminal during the driving period;
a sensor that receives the pixel sensing signal from the output terminal, senses the pixel sensing signal, and provides a sensing signal for conversion into sensing data; and
A third selection circuit that transmits the pixel sensing signal of the output terminal to the sensor in the sensing period and transmits the source signal of the output terminal to the display panel in the driving period,
The first selection circuit includes a first switch for providing the reference voltage to the first input terminal in the sensing period and a second switch for transmitting the source signal to the first input terminal in the driving period,
The second selection circuit includes a third switch that forms a feedback path between the second input terminal and the output terminal in the driving period and a fourth switch that provides the pixel signal to the second input terminal in the sensing period, and,
The third selection circuit includes a fifth switch that transmits the source signal of the output terminal to the display panel in the driving period and a sixth switch that transmits the pixel sensing signal of the output terminal to the sensor in the sensing period. Source driver for the display device. The method of claim 12, wherein the sensor:
A transistor driven by the pixel sensing signal; and
A current sensor that senses the amount of current according to the operation of the transistor and provides the sensing signal. The method of claim 12, wherein the sensor:
A transistor driven by the pixel sensing signal;
a load circuit to which a voltage corresponding to the amount of current according to the operation of the transistor is applied; and
A source driver for a display device comprising: a voltage sensor providing the sensing signal corresponding to the voltage of the load circuit. delete According to claim 12,
The fourth switch and the fifth switch output the source signal to the display panel and receive the pixel signal of the display panel through the same channel.

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