CN102063885B - Display panel drive circuit - Google Patents

Abstract

The present invention relates to a driving circuit of a display panel, which comprises a pre-charge switch coupled between a pre-charge source and a capacitor of a display panel, a buffer circuit buffering a data signal to generate a buffer signal, a plurality of impedance components connected in series, and generating a plurality of driving signals between the impedance components according to the buffer signal, wherein the driving circuit turns on the pre-charge switch so that the pre-charge source charges the capacitor and then charges a pair of capacitors with one of the driving signals, thereby shortening the driving time and avoiding energy consumption on the resistor, thereby saving the power of the display device.

Description

Display panel drive circuit

technical field

The present invention relates to a driving circuit, in particular to a driving circuit of a 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 many people. Most of the early monitors were cathode ray tube (Cathode Ray Tube, CRT) monitors. Due to their large size and high power consumption, and the radiation generated, there are doubts about harming the health of users who use the monitors for a long time. Therefore, today Displays on the market 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.

Based on the above, the liquid crystal display controls the light transmittance of the liquid crystal unit according to the data signal to display images. Since the active matrix liquid crystal display uses an active control switching device, this type of liquid crystal display has advantages in displaying animation, and a thin film transistor (TFT) is mainly used as a switching device for the active matrix liquid crystal display.

Please refer to FIG. 1 , which is a schematic diagram of a driving system of a liquid crystal display in the prior art. As shown in the figure, the driving system includes a display panel 10', a scanning driving circuit 12', a data driving circuit 14', a timing control circuit 16' and a reference voltage generating circuit 18'. The display panel 10' is used to display images, the scanning driving circuit 12' is used to generate and transmit a scanning signal to the display panel 10' to drive a thin film transistor of the display panel 10', and the data driving circuit 14' is used to generate and transmit a scanning signal The data signal is sent to the display panel 10' to display images according to the data signal. The timing control circuit 16' generates a timing control signal and sends the timing control signal to the scanning driving circuit 12' and the data driving circuit 14' respectively to control the scanning driving The circuit 12' and the data driving circuit 14 respectively transmit the scan signal and the data signal to the display panel 10' for displaying images. In addition, the reference voltage generating circuit 18' generates a reference voltage and transmits the reference voltage to the data driving circuit 14', so that the data driving circuit 14' generates data signals according to the timing control signal and the reference voltage.

Wherein, please refer to FIG. 2 , which is a schematic diagram of a reference voltage generating circuit in the prior art. As shown in the figure, when the digital display data corresponding to RGB respectively consist of 6 bits, the reference voltage generating circuit 18' can output 64 kinds of analog voltages V0-V63 respectively corresponding to 2 ⁶ =64 kinds of gray scale display. The reference voltage generating circuit 18' is composed of a resistor divider circuit connected in series with resistors R0-R7. Each of the resistors R0 to R7 is connected to eight resistors in series. That is, as shown in FIG. 3 , eight resistors R01 , R02 , . Therefore, the reference voltage generating circuit 18' is composed of 64 resistors to generate voltages V0˜V63.

Since the reference voltage generating circuit 18' needs to use about 64 resistors in order to generate 64 different voltage levels, this will increase the area of the reference voltage generating circuit 18', thereby increasing the area of the display device. Furthermore, in order to reduce the area of the reference voltage generating circuit 18', a resistor with a larger resistance must be used, but increasing the resistance of the resistor will affect the driving capability of the data driving circuit 14'. Furthermore, when the data driving circuit 14' drives the display panel 10' through these resistors, a large amount of energy must be consumed on the resistors, which wastes the power of the display device.

Therefore, how to propose a novel display panel driving circuit for the above problems, which can reduce the number of resistors used without affecting the driving capability of the data driving circuit 14', thereby reducing the area of the display device, and can solve the above problems. The problem.

Contents of the invention

One of the objectives of the present invention is to provide a driving circuit for a display panel, which uses a pre-charging source to charge the capacitor of the display device first, thereby shortening the driving time.

One of the objectives of the present invention is to provide a display panel driving circuit, which uses a pre-charging source to charge the capacitor of the display device first, so as to avoid energy consumption on the resistor, thereby saving the power of the display device.

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

a pre-charge source;

a pre-charging switch coupled between the pre-charging source and a capacitor of the display panel;

a buffer circuit for buffering a data signal to generate a buffer signal; and

a plurality of impedance components, the impedance components are connected in series with each other and coupled to the buffer circuit, and a plurality of driving signals are generated between the impedance components according to the buffer signal;

Wherein, the driving circuit turns on the pre-charging switch so that the pre-charging source charges the capacitor, and then charges the capacitor with a pair of the driving signals.

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

In the present invention, further include:

An analog-to-digital conversion circuit is used to convert an input signal to generate the data signal.

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, the driving circuit provides a positive voltage signal or a zero voltage signal of the pre-charging source to the capacitor according to the polarity inversion of the liquid crystal of the display panel.

In the present invention, further include:

A plurality of switches, one end of which is respectively coupled between the impedance elements of the impedance elements, and the other end is coupled to the display panel, so as to turn on one of the switches according to a control signal to generate and transmit the drive signal to this capacitor.

In the present invention, further include:

An analog-to-digital conversion circuit generates the control signal to turn on one of the switches according to an input signal.

In the present invention, wherein the buffer circuit includes:

a first buffer for buffering the data signal to generate a first buffered signal; and

A second buffer is used for buffering the data signal to generate a second buffered signal.

In the present invention, the impedance components are a resistor.

In the present invention, the second buffer is an operational amplifier.

In the present invention, the first buffer is an operational amplifier.

The beneficial effect of the present invention: the driving circuit of the display panel provided by the present invention includes a pre-charging source, a pre-charging switch, a buffer circuit and complex impedance components. The pre-charge switch is coupled between the pre-charge source and a capacitor of the display panel; the buffer circuit is used to buffer a data signal to generate a buffer signal; multiple impedance components are connected in series with each other and coupled to the buffer circuit, and according to the buffer signal A plurality of driving signals are generated between these impedance components; wherein, the driving circuit turns on the pre-charging switch so that the pre-charging source charges the capacitor, and then charges a pair of capacitors in the driving signals to shorten the driving time. And energy consumption on the resistor can be avoided, thereby saving the power of the display device.

Description of drawings

Fig. 1 is the schematic diagram of the driving system of the liquid crystal display of prior art;

2 is a schematic diagram of a reference voltage generation circuit in the prior art;

3 is a schematic diagram of a detailed reference voltage generation circuit in the prior art;

Fig. 4 is the schematic diagram of the drive system of liquid crystal display of the present invention;

Fig. 5 is a block diagram of a preferred embodiment of the present invention;

FIG. 6 is a driving timing diagram of a preferred embodiment of FIG. 5; and

FIG. 7 is a block diagram of another preferred embodiment of the present invention.

[Simple description of figure number]

current technology:

10' display panel 12' scanning drive circuit

14' data drive circuit 16' timing control circuit

18' reference voltage generating circuit

this invention:

10 display panel 100 capacitance

12 scan drive circuit 14 data drive circuit

140 first pre-charge switch 141 second pre-charge switch

142 buffer circuit 1420 first buffer

1421 second buffer 143 impedance component

144 impedance components 146 impedance components

148 Impedance Components 15 Analog-to-Digital Conversion Circuits

150 first switch 152 second switch

154 third switch 16 timing control circuit

18 gamma circuit 20 memory units

detailed description

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. 4 , which is a schematic diagram of the driving system of the liquid crystal display of the present invention. As shown in the figure, the driving system includes a display panel 10 , a scan driving circuit 12 , a data driving circuit 14 , a timing control circuit 16 and a Gamma circuit 18 . The display panel 10 is used to display images, the scan driving circuit 12 is used to generate and transmit a scan signal to the display panel 10 to drive a thin film transistor of the display panel 10, and the data drive circuit 14 is used to generate and transmit a data signal to the display panel 10, to display images according to the data signal, the timing control circuit 16 generates a timing control signal, and transmits the timing control signal to the scan driving circuit 12 and the data driving circuit 14 respectively, so as to control the scanning driving circuit 12 and the data driving circuit 14 to transmit Scanning signals and data signals are sent to the display panel 10 to display images. In addition, the gamma circuit 18 generates a reference voltage and transmits the reference voltage to the data driving circuit 14 so that the data driving circuit 14 generates data signals according to the timing control signal and the reference voltage.

Please refer to FIG. 5 , which is a block diagram of a preferred embodiment of the present invention. As shown in the figure, the driving circuit of the display panel of the present invention is applied in the data driving circuit 14 to receive 64 voltage levels generated by the gamma circuit 18. Since the driving circuit of the present invention can receive 8-bit signals, Therefore, the data driving circuit 14 needs to use 8 driving circuits to receive and process 64 voltage levels, and this embodiment only uses one driving circuit for illustration. The driving circuit of the present invention includes a first precharge source AVDD, a first precharge switch 140 , a buffer circuit 142 and complex impedance components 143 , 144 , 146 , 148 . The first pre-charge switch 140 is coupled between the pre-charge source AVDD and a capacitor 100 of the display panel 10. The buffer circuit 142 is used to buffer a data signal to generate a buffer signal. The complex impedance components 143, 144, 146, 148 are connected in series with each other and coupled to the buffer circuit 142. These impedance components 143, 144, 146, 148 generate complex driving signals between these impedance components 143, 144, 146, 148 according to the buffered signals, and the driving circuit is first turned on. The first pre-charging switch 140 enables the first pre-charging source AVDD to charge the capacitor 100, and then uses one of the driving signals to charge the capacitor 100. Please refer to FIG. 6 together, which is a driving sequence diagram of the driving circuit. As shown in the figure, the dotted line represents that the driving circuit charges the capacitor 100 without precharging, and the solid line represents that the driving circuit of the present invention charges the capacitor 100 in a precharging manner. Charging, as can be seen from the figure, the drive circuit of the present invention charges the capacitor 100 with the first pre-charge source AVDD during the period from T1 to T2, and charges the capacitor 100 with the driving signal during the period from T2 to T3, so , the driving circuit of the present invention has completed driving the display panel 10 at T3, and can shorten the time for the driving circuit to charge the capacitor 100, and shorten the driving time for the data driving circuit 14 to the display panel 10, thereby increasing the efficiency of the display device . Furthermore, since the time for the driving circuit to charge the capacitor 100 is shortened, the time for energy consumption on the impedance components 143 , 144 , 146 , 148 can be reduced, thereby saving power. Wherein, the impedance component 143, 144, 146, 148 is a resistor.

In addition, the driving circuit of the display panel of the present invention further includes an analog-to-digital conversion circuit 15 for converting an input signal to generate a data signal. Wherein, the analog-to-digital conversion circuit 15 is coupled to the gamma circuit 18 to receive a correction data generated by the gamma circuit 18 as an input signal, and the gamma circuit 18 generates correction data according to a gamma curve. Furthermore, the analog-to-digital conversion circuit 15 is further coupled to a memory unit 20 for storing complex pixel data. The analog-to-digital conversion circuit 15 receives the pixel data and correction data as input signals to generate data signals. Wherein, the memory unit 20 is a random access memory (random access memory, RAM).

Please refer to FIG. 5 again, a first switch 150 , a second switch 152 and a third switch 154 are respectively provided between the impedance elements 143 , 144 , 146 , and 148 . The analog-to-digital conversion circuit 15 can generate a control signal to turn on/off the first switch 150 , the second switch 152 or the third switch 154 according to the pixel data stored in the memory unit 20 . Furthermore, the analog-to-digital conversion circuit 15 will first control the first pre-charge switch 140 or the second pre-charge switch 141 to be turned on, so as to charge the capacitor 100 first, and then control the first pre-charge switch 140 after a period of time. Or the second pre-charging switch 141 is turned off, and one of the first switch 150 , the second switch 152 or the third switch 154 is turned on, so as to continuously charge the capacitor 100 .

Moreover, the buffer circuit 142 includes a first buffer 1420 and a second buffer 1421 . The first buffer 1420 is used to buffer the data signal to generate a first buffered signal, the second buffer is used to buffer the data signal to generate a second buffered signal, the impedance components 143, 144, 146, 148 The driving signal is generated by the voltage difference between the first buffer signal and the second buffer signal generated by the first buffer 1420 and the second buffer 1421 . Wherein, the first buffer 1420 and a second buffer 1421 are an operational amplifier.

In addition, since the polarity of the liquid crystal in the display panel 10 needs to be reversed to avoid accumulating charges and affecting the display quality, the driving circuit of the present invention further includes a second pre-charging source VSS and a second pre-charging switch 141, The driving circuit provides the first pre-charging source AVDD or the second pre-charging source VSS to the capacitor 100 through the first pre-charging switch 140 and the second pre-charging switch 141 according to the polarity inversion of the liquid crystal of the display panel 10 . Wherein, the first pre-charging source AVDD and the second pre-charging source VSS can be coupled to any power terminal in the display device.

Please refer to FIG. 7 , which is a block diagram of another preferred embodiment of the present invention. As shown in the figure, the difference between this embodiment and the embodiment of FIG. 5 lies in that the first precharge source AVDD and the second precharge source VSS of this embodiment are coupled to the output of the first buffer 1420 respectively. terminal and the output terminal of the second buffer 1421, in this way, during the process of precharging the driving circuit with the first precharging source AVDD or the second precharging source VSS, no overshoot will occur due to the long precharging time Charging phenomenon, and simplify the control of switching time.

To sum up, the driving circuit of the display panel of the present invention uses a pre-charging switch to charge a capacitor of a display panel with a pre-charging source, and then generates a capacitor between these impedance components according to the buffered signal. One of the plurality of driving signals charges the capacitor to shorten the driving time and avoid energy consumption on the resistor, thus saving the power of the display device.

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 (10)

1. A drive circuit for a display panel, characterized in that it comprises: a pre-charge source; a pre-charging switch coupled between the pre-charging source and a capacitor of the display panel; An analog-to-digital conversion circuit for converting an input signal to generate a data signal; a buffer circuit for receiving and buffering the data signal of the analog-to-digital conversion circuit to generate a buffer signal; and a plurality of impedance components, the impedance components are connected in series with each other and coupled to the buffer circuit, and a plurality of driving signals are generated between the impedance components according to the buffer signal; Wherein, the driving circuit turns on the pre-charging switch so that the pre-charging source charges the capacitor, and then charges the capacitor with a pair of the driving signals. 2. The driving circuit of the display panel according to claim 1, wherein it is applied to a data driving circuit of the display panel. 3. The driving circuit of the display panel 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 of the display panel according to claim 1, wherein the driving circuit provides a positive voltage signal or a zero voltage signal of the pre-charging source according to the polarity inversion of the liquid crystal of the display panel to this capacitor. 5. The driving circuit of the display panel according to claim 1, further comprising: A plurality of switches, one end of which is respectively coupled between the impedance elements of the impedance elements, and the other end is coupled to the display panel, so as to turn on one of the switches according to a control signal to generate and transmit the Drive signal to this capacitor. 6 . The driving circuit of the display panel according to claim 5 , wherein the analog-to-digital conversion circuit generates the control signal to turn on one of the switches according to the input signal. 7. The driving circuit of the display panel according to claim 1, wherein the buffer circuit comprises: a first buffer for buffering the data signal to generate a first buffered signal; and A second buffer is used for buffering the data signal to generate a second buffered signal. 8. The driving circuit of the display panel according to claim 1, wherein the impedance components are resistors. 9. The driving circuit of the display panel according to claim 7, wherein the second buffer is an operational amplifier. 10. The driving circuit of the display panel according to claim 7, wherein the first buffer is an operational amplifier.