JP2604750Y2 - Display drive - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to a display driving device,
Specifically, the present invention relates to a display driving device for driving a matrix type liquid crystal display panel.

[0002]

2. Description of the Related Art In the display of an LCD television screen, high resolution,
High-performance and high-quality display functions such as high gradation, high-speed response, and high contrast are required. The display method is TN
(Twisted Nematic) type, STN (Supertwisted Nemati)
In addition to the c) type, a ferroelectric type, an antiferroelectric type, and the like are used, and an active matrix drive using a TFT (Thin Film Transistor) and a simple matrix drive are employed as a drive method.

A display driving device for driving the above-mentioned liquid crystal display device basically includes a control unit for generating timing required for driving such as video data and a frame signal, and a power supply unit for generating and supplying a video driving potential. And a drive unit for supplying a drive waveform to the liquid crystal panel using a timing signal from the control unit, video data, and a liquid crystal drive potential supplied from the power supply unit.

[0004]

However, the liquid crystal drive potential is not equal to the drive unit, the liquid crystal drive bias power supply terminal of the drive IC, and 1
Because of the one-to-one connection, there is a drawback that the number of bias potentials for driving the liquid crystal is limited to the number. For example,
In a simple matrix drive system such as a TN type or an STN type, four types of liquid crystal drive bias potentials are usually commercially available.

However, in a liquid crystal display device such as an antiferroelectric liquid crystal in which a writing threshold voltage exists in positive and negative voltages and a voltage having a polarity opposite to that of the writing voltage is applied before writing. 5 to 8 types of driving bias potentials are required. In contrast to the case where various types of bias potentials are required, if a drive device is applied for each type of required bias potential, the mass production effect of the drive device cannot be obtained, and the device becomes expensive. There was a problem that would.

Accordingly, an object of the present invention is to provide a display driving device capable of driving a liquid crystal display device by setting a bias potential at the time of driving the liquid crystal to be more than the number of liquid crystal driving bias power supply terminals of the driving IC. I do.

[0007]

According to the first aspect of the present invention, a liquid crystal display device is driven to achieve the above object.
In a display driver for supplying a power supply potential to a bias power supply terminal of a drive circuit , a plurality of liquid crystal drive bias potentials are generated.
It has multiple power supply circuits that generate
The plurality of liquid crystal driving bias potentials generated as one set
And a power supply means for outputting, of the output from said power supply means
One of a plurality of sets of liquid crystal driving bias potentials
Selection and output to the bias power supply terminal of the drive circuit.
Selecting means, and a liquid crystal driving bar selected by the selecting means.
Switch the pair of bias potentials in synchronization with the frame signal
Control means . The display driving device, the
Of the liquid crystal driving bias potential supplied from the power supply means.
Determining means for determining an unstable state; and
The bias voltage for driving the liquid crystal is determined to be unstable.
Based on the signal to stop the display of the display drive device,
It is desirable to provide a means for providing to the drive circuit.

[0008]

In the present invention, a plurality of sets of liquid crystal driving bias potentials are generated from each power supply circuit by the power supply means, and the input to the bias power supply terminal of the liquid crystal display device is switched and output by the selection means at a predetermined timing. .

Therefore, the liquid crystal driving potential can be increased in a pseudo manner, and a liquid crystal driving waveform having many potential levels can be supplied even to a liquid crystal driving IC having a small liquid crystal driving bias potential.

[0010]

An embodiment will be described below with reference to the drawings.

FIG. 1 is a diagram showing one embodiment of the display driving device of the present invention.

First, the configuration will be described. FIG. 1 is an overall configuration diagram of a display driving device.

In FIG. 1, a display driving device 10 includes a power supply circuit A11, a power supply circuit B12, a multiplexer 13, a comparator A14, a comparator B15, an EX-OR circuit 16, a scan electrode drive circuit 17, a shift register 18, a latch circuit. A
19, latch circuit B20, decoder 21, and control unit 22
It is composed of

In a liquid crystal display panel (not shown) to which the output of the decoder 21 is output, a plurality of scanning electrodes and a plurality of signal electrodes are arranged to face each other with a liquid crystal layer interposed therebetween, and are arranged in a matrix. A signal electrode drive circuit (not shown) for driving the signal electrodes and a scan electrode drive circuit 17 for driving the scan electrodes are provided.

The power supply circuit A11 generates four liquid crystal drive bias potentials and supplies them to the multiplexer 13 and the comparator A14, respectively. The power supply circuit B12 generates four liquid crystal drive bias potentials and supplies them to the multiplexer 13 and the comparator B15, respectively.

The power supply circuit A11 and the power supply circuit B12
Generates and supplies a liquid crystal drive bias potential equal to or more than the number of bias power supply terminals to the scan electrode drive circuit 17 for driving the liquid crystal display device. In the present embodiment, the power supply circuit A11 and the power supply circuit B12 are provided separately. The liquid crystal drive potential is supplied four by four. The liquid crystal drive bias potentials generated by the power supply circuits A11 and B12 are output to the multiplexer 13.

The multiplexer 13 switches to output one of the power supply circuits A11 and B12 to the scan electrode drive circuit 17 based on a control signal from the control unit 22. The multiplexer 13 is composed of a plurality of analog switches, and has a sufficiently low on-resistance.

The comparator A14 and the comparator B15 are connected to the power supply circuit A11 and the power supply circuit B12, respectively, determine whether or not the driving power supply potential switched by the multiplexer 13 is stabilized, and determine whether the comparison result is EX-OR. Circuit 16
And outputs the result to the scan electrode drive circuit 17. Here, a signal for stopping the display is provided to the scan electrode drive circuit 17 during a transition period when the drive power supply potential is not stable.

The scan electrode drive circuit 17 comprises a driver circuit, a scan shift register, and the like. The shift register sequentially scans each scan line according to the scan shift clock signal CPV and the scan side drive signal φV from the control unit 22. The pixel voltages S1 to G1 supplied to the data line DL are supplied to a decoder 21 described later while supplying predetermined scanning signals G1 to Gn.
Supply Sm.

The data-side shift register 18 receives the data transfer clock CPH and the data DATA from the control unit 22. The shift register 18 shifts the data DATA by the data transfer clock CPH and latches the data.
9 is output.

The latch circuit A19 takes in and latches output data from the shift register 18 according to a latch signal L1 from the control unit 22.

The latch circuit B20 takes in and latches the latch data from the latch circuit A19 according to the latch signal L2 from the control unit 22.

The control section 22 outputs a video signal, a timing signal, and a control signal to each section based on the synchronization signal to control each section and the entire apparatus.

The decoder 21 determines the pixel voltages S1 to Sm based on the data output from the latch circuit B20 and the frame signal DF, and supplies them to the data line DL.

Next, the operation of this embodiment will be described.

In the power supply circuits A11 and B12,
The four different liquid crystal driving bias potentials are supplied to the multiplexer 13, the comparator A14, or the comparator B15, respectively.

That is, the power supply circuit A11 and the power supply circuit B
12 is a scan electrode drive circuit 17 for driving the liquid crystal display device
And generates and supplies a liquid crystal driving bias potential equal to or more than the number of bias power supply terminals.

In the multiplexer 13, a set of liquid crystal drive bias potentials from the power supply circuit A 11 or the power supply circuit B 12 is supplied to the liquid crystal drive bias power supply terminal of the scan electrode drive circuit 17 in synchronization with the frame signal F from the control unit 22. Select and switch. For this reason, four liquid crystal drive bias potentials from the power supply circuit A11 and four liquid crystal drive bias potentials from the power supply circuit B12 are switched and supplied to the scan electrode drive circuit 17 for each frame. That is, the scanning electrode driving circuit 17 outputs eight liquid crystal driving bias potentials.

The power supply circuit A11 and the power supply circuit B12
The liquid crystal driving potential generated at the comparators A14 and B
15 and the comparator A14 and the comparator B15
The multiplexer 13 determines whether or not the switched drive power supply potential is stabilized, and supplies a signal to stop the display to the scan electrode drive circuit 17 during a transition period in which the drive power supply potential is not stabilized.

As described above, the display driving apparatus 10 according to the present embodiment selects a power supply circuit A11 and a power supply circuit B12, and selects one of the power supply circuit A11 and the power supply circuit B12 to provide a plurality of sets of liquid crystal driving biases. A multiplexer 13 for outputting a potential; a comparator A14, a comparator B15 for determining whether or not the drive power supply potential is stable; and an EX-OR circuit 16; Since the input to the liquid crystal drive output bias power supply terminal of the electrode drive circuit 17 is switched by the multiplexer 13 in synchronization with the frame signal from the control unit 22, the liquid crystal drive potential is pseudo-increased. Even a liquid crystal driving IC having only four potentials has five potentials and six potentials.
A liquid crystal drive waveform having a potential voltage level can be generated, and the effect can be exerted on a liquid crystal display element requiring a large number of liquid crystal drive voltages, such as an antiferroelectric liquid crystal.

[0031]

According to the present invention, power supply means having a plurality of power supply circuits for generating a plurality of sets of liquid crystal drive bias potentials, and a bias power supply for a liquid crystal display device by selecting the plurality of sets of liquid crystal drive potentials Since there is provided a selection means for outputting to the terminal, the liquid crystal driving potential can be increased in a pseudo manner, and a liquid crystal driving waveform having many potential levels can be generated.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of a display driving device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Display drive device 11 Power supply circuit A 12 Power supply circuit B 13 Multiplexer 14 Comparator A 15 Comparator B 16 EX-OR circuit 17 Scan electrode drive circuit 22 Control part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G09G 3/36 G02F 1/133 G09G 3/20

Claims (2)

(57) [Scope of request for utility model registration] In a display driving device for supplying a power supply potential to a bias power supply terminal of a drive circuit for driving a liquid crystal display device, a plurality of power supply circuits for generating a plurality of liquid crystal drive bias potentials are provided.
A plurality of liquids, each of the plurality of
Power supply means for outputting a set of crystal drive bias potentials, and a liquid crystal drive bias voltage output from the power supply means.
And selecting one of the plurality of sets of
Selecting means for outputting to a bias power terminal, and a liquid crystal driving bias potential selected by the selecting means.
Control means for switching the set in synchronization with the frame signal
And a display drive device comprising: 2. A liquid crystal drive supplied from said power supply means.
Determining means for determining an unstable state of the bias potential for use; The liquid crystal drive bias potential is unstable due to the determination means
The display of the display driving device is stopped based on the signal that has determined the state.
Means for giving a signal to stop to the drive circuit; The display according to claim 1, further comprising:
Drive.