CN101783126B - Drive circuit for display panel with capacitive drive - Google Patents

Abstract

The invention relates to a driving circuit of a display panel with capacitance driving, which is characterized in that an analog-digital conversion circuit is used for converting an input signal to generate a digital signal; a capacitor for receiving the digital signal and generating a driving signal to drive a display panel; a switching circuit controls the analog-to-digital conversion circuit to transmit the digital signal to the capacitor according to a switching signal, or the capacitor transmits the driving signal to the display panel. Therefore, the display panel is driven by a capacitor driving mode, so that the area of the data driving circuit is effectively reduced under the requirement of high-digit images, and the cost is further saved. And, the power supply system of the display device is simplified in the application of a larger voltage range.

Description

Drive circuit for display panel with capacitive drive

technical field

The present invention relates to a driving circuit, in particular to a driving circuit with a capacitively driven display panel.

Background technique

Nowadays, with the vigorous development of science and technology, the types of information products are introduced to meet the different needs of the public. Most of the early monitors were cathode ray tube (CRT) monitors. Due to their large size and high power consumption, and the radiation generated by them may be harmful to the health of users who use the monitors for a long time, so , the displays on the market today will gradually be replaced by liquid crystal displays (Liquid Crystal Display, LCD). Liquid crystal displays have the advantages of being thin, light and small, low radiation and low power consumption, and thus become the mainstream in the current market.

Moreover, with the rapid advancement of panel production technology in recent years, the production cost of touch panels has been greatly reduced, so touch panels have been widely used in general consumer electronics products, such as mobile phones, Small electrical appliances such as digital cameras, digital music players (MP3), personal digital assistants (PDA), and satellite navigation devices (GPS). Users can perform interactive input operations, which greatly improves the amicability of the communication interface between humans and machines, and improves the efficiency of input operations.

In order to solve a wide range of power supply specifications, such as 2.3V to 4.6V, and reduce the area of the driver chip that drives the display panel under the application of a single power supply for mobile phones, the industry has gradually proposed a driving method that can meet the two requirements at the same time. . Generally, the data driving circuit (Source driver) of the display device uses an operational amplifier (Op-amp) or a resistor divider to drive the display panel. However, the driver chip itself needs to build a power supply system and a DC-DC converter (DC-DC converter). In this way, the architecture of the driver chip is not only complicated but also requires external components, and even higher digital video requirements or RGB three gamma ( When Gamma) curves are used together, the area of the digital-to-analog circuit will increase rapidly due to the increase in the number of Gamma gray-scale voltages, thereby increasing the cost of the driver chip.

Therefore, how to propose a novel capacitively driven display panel drive circuit for the above problems, so that the power supply system of the display device can be simplified in the application of a large voltage range, and the data can be effectively reduced under the high-bit image demand The area of the driving circuit is reduced, thereby saving the cost, so that the above-mentioned problems can be solved.

Contents of the invention

One of the objectives of the present invention is to provide a driving circuit with a capacitively driven display panel, which drives the display panel in a capacitively driven manner, so that the area of the data driving circuit can be effectively reduced under the high-digital image demand, and further cut costs.

One of the objectives of the present invention is to provide a driving circuit for a display panel with capacitive driving, so that the power supply system of the display device can be simplified in the application of a larger voltage range.

In order to achieve the above object, the present invention is a driving circuit of a display panel driven by a capacitor, which includes:

An analog-to-digital conversion circuit for converting an input signal to generate a digital signal;

A capacitor receives the digital signal to generate a driving signal to drive a display panel; and

A switching circuit, according to a switching signal, controls the analog-to-digital conversion circuit to transmit the digital signal to the capacitor, or the capacitor to transmit the driving signal to the display panel.

In the present invention, wherein the capacitor drives the display panel is to drive a pixel capacitor of the display panel.

In the present invention, it further includes:

A gamma circuit generates and transmits the input signal to the analog-to-digital conversion circuit according to a gamma curve.

In the present invention, it is applied to a data driving circuit of the display panel.

In the present invention, a switching frequency of the switching circuit is controlled by a timing control circuit.

In the present invention, when the capacitor receives the digital signal, the digital signal charges the capacitor.

In the present invention, when the capacitor drives the display panel, the driving signal is to discharge the display panel.

In the present invention, when the capacitor receives the digital signal, the capacitor is coupled between a first terminal and a second terminal of the analog-to-digital conversion circuit.

In the present invention, when the capacitor drives the display panel, the capacitor is coupled between a third terminal of the analog-to-digital conversion circuit and the display panel.

In the present invention, it is applied to the display panel of the handheld device.

The present invention has beneficial effects: the drive circuit provided by the present invention has a capacitively driven display panel, which drives the display panel in a capacitively driven manner, so that the area of the data drive circuit can be effectively reduced under the high-digital image demand, thereby saving costs. Moreover, the power supply system of the display device can be simplified in the application of a larger voltage range.

Description of drawings

Fig. 1 is the block diagram of the data driving circuit of a preferred embodiment of the present invention;

Fig. 2 is the parasitic RC equivalent circuit of the source line of the display panel of the present invention;

Fig. 3 is the block diagram of the driving unit of a preferred embodiment of the present invention;

FIG. 4A is a schematic diagram of the action of the driving unit of a preferred embodiment of the present invention; and

FIG. 4B is a schematic diagram of the operation of the driving unit in another preferred embodiment of the present invention.

[Simple description of figure numbers]

this invention:

1 Data drive circuit 10 Gamma circuit

12 first drive unit 120 analog-to-digital conversion circuit

122 Capacitor 124 Switch

14 Second drive unit 16 Third drive unit

18 fourth drive unit 20 display panel

200 resistor 202 capacitor

Detailed ways

In order to have a further understanding and understanding of the structural features of the present invention and the achieved effects, the preferred embodiments and accompanying drawings are used for a detailed description, as follows:

Please refer to FIG. 1 , which is a block diagram of a data driving circuit according to a preferred embodiment of the present invention. As shown in the figure, the data driving circuit 1 includes a Gamma circuit 10 , a first driving unit 12 , a second driving unit 14 , a third driving unit 16 and a fourth driving unit 18 . The gamma circuit 10 generates complex input signals according to a gamma curve, and these input signals are voltage signals of different levels, and the gamma circuit 10 transmits these input signals to the first driving unit 12 and the second driving unit 14 , the third driving unit 16 and the fourth driving unit 18 . The first driving unit 12, the second driving unit 14, the third driving unit 16 and the fourth driving unit 18 respectively generate a driving signal according to a data signal and the input signals, and transmit the driving signals to a display panel 20, to drive the display panel 20. Wherein, the first driving unit 12 , the second driving unit 14 , the third driving unit 16 and the fourth driving unit 18 respectively generate driving signals to control each row of pixels of the display panel 20 .

In addition, please refer to FIG. 2 , which is a parasitic RC equivalent circuit of the source line of the display panel of the present invention. As shown in the figure, each pixel of a thin-film transistor (Thin-Flim Transistor, TFT) on the source line in the display panel can be equivalent to a resistor 200 connected in series with a capacitor 202 . This is a technology well known to those familiar with this technical field, so no more praises will be given here.

Please refer to FIG. 3 , which is a block diagram of a driving unit according to a preferred embodiment of the present invention. As shown in the figure, the driving unit of the capacitor-driven display panel of the present invention includes an analog-to-digital conversion circuit 120 , a capacitor 122 and a switching circuit 124 . The analog-to-digital conversion circuit 120 is used to convert input signals to generate a digital signal, that is, to receive the input signals generated by the gamma circuit 10, and to generate a digital signal according to a data signal, and the capacitor 122 receives the digital signal to generate A driving signal to drive the display panel 20, the switching circuit 124 controls the analog-to-digital conversion circuit 120 to transmit the digital signal to the capacitor 122 according to a switching signal, or controls the capacitor 122 to transmit the driving signal to the display panel 20, that is, the switching circuit 124 will Receives a switching signal generated by a timing control circuit (not shown in the figure), and the switching circuit 124 switches the capacitor 122 to charge and discharge according to the switching signal, so as to drive the display panel 20 . In this way, the present invention drives the display panel 20 by driving the capacitor 122, avoiding the use of an operational amplifier or resistive voltage division to drive the display panel 20, so that the area of the data driving circuit can be effectively reduced under the high-digital image demand, and further cut costs. Moreover, the power supply system of the display device can be simplified in the application of a larger voltage range. The following is an illustration of how the switching circuit 124 switches the capacitor 122 to drive the display panel 20 .

Please refer to FIG. 4A and FIG. 4B together, which are schematic diagrams illustrating the operation of the driving unit in a preferred embodiment of the present invention. As shown in the figure, the switching circuit 124 first switches the capacitor 122 to receive the digital signal generated by the analog-to-digital conversion circuit 120 according to the switching signal, so that the analog-to-digital conversion circuit 120 first charges the capacitor 122 to generate a driving signal. That is, the analog-to-digital conversion circuit 120 includes a first terminal, a second terminal and a third terminal. When the analog-to-digital conversion circuit 120 charges the capacitor 122, the capacitor 122 is coupled between the first end and the second end of the analog-to-digital conversion circuit 120, as shown in FIG. 4A, so that the capacitor 122 stores charges to generate a driving signal, When the switching circuit 124 makes the capacitor 122 transmit a driving signal to the display panel 20 according to the switching signal, so as to drive the display panel 20 . That is, the switching circuit 124 switches the capacitor 122 to be coupled between the third terminal of the analog-to-digital conversion circuit 120 and the display panel 20 according to the switching signal, so that the driving signal generated by the charge stored in the capacitor 122 is transmitted to a storage capacitor of the display panel 20 (not shown in the figure) to drive the display panel 20 . In this way, the present invention avoids the use of operational amplifiers or resistive voltage dividers to drive the display panel 20 , so that the area of the data driving circuit can be effectively reduced under the demand of high-bit images, thereby saving costs. Moreover, the power supply system of the display device can be simplified in the application of a larger voltage range.

In summary, the driving circuit of the display panel driven by a capacitor of the present invention uses an analog-to-digital conversion circuit to convert an input signal to generate a digital signal, and transmits the digital signal to a capacitor to generate a driving circuit. signal to drive a display panel; a switching circuit controls the analog-to-digital conversion circuit to transmit the digital signal to the capacitor according to a switching signal, or the capacitor transmits the driving signal to the display panel. In this way, the display panel is driven by capacitive driving, so that the area of the data driving circuit can be effectively reduced under the demand of high-bit images, thereby saving cost. Moreover, the power supply system of the display device can be simplified in the application of a larger voltage range.

In summary, it is only a preferred embodiment of the present invention, and is not intended to limit the implementation scope of the present invention. All equivalent changes and Modifications should be included within the scope of the claims of the present invention.

Claims (8)

1. A driving circuit utilizing a capacitance-driven display panel, characterized in that it comprises: An analog-to-digital conversion circuit for converting an input signal to generate a digital signal; A capacitor receives the digital signal to generate a driving signal to drive a display panel; and A switching circuit, according to a switching signal, controls the analog-to-digital conversion circuit to transmit the digital signal to the capacitor, or the capacitor to transmit the driving signal to the display panel; When the capacitor receives the digital signal, the digital signal charges the capacitor, and when the capacitor drives the display panel, the driving signal discharges the display panel. 2. The driving circuit according to claim 1, wherein the capacitor driving the display panel is driving a pixel capacitor of the display panel. 3. The driving circuit according to claim 1, further comprising: A gamma circuit generates and transmits the input signal to the analog-to-digital conversion circuit according to a gamma curve. 4. The driving circuit according to claim 1, wherein it is applied to a data driving circuit of the display panel. 5. The driving circuit according to claim 1, wherein a switching frequency of the switching circuit is controlled by a timing control circuit. 6. The driving circuit according to claim 1, wherein when the capacitor receives the digital signal, the capacitor is coupled between a first terminal and a second terminal of the analog-to-digital conversion circuit. 7. The driving circuit according to claim 1, wherein when the capacitor drives the display panel, the capacitor is coupled between a third terminal of the analog-to-digital conversion circuit and the display panel. 8. The driving circuit according to claim 1, wherein it is applied to a display panel of a handheld device.