JPH0140356B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a liquid crystal display driving device. Liquid crystal displays have the characteristics of low voltage drive, low power consumption, easy visibility in bright places, easy reduction in thickness, and ease of creating various display patterns. It is used in a wide variety of applications because of its ability to display images for a long time using batteries in combination with devices. There are static drive and dynamic drive to drive a liquid crystal display and perform a predetermined display. In particular, dynamic drive uses a plurality of row electrodes (X1' to Xm') as shown in Figure 1. , a predetermined display is performed on the liquid crystal segment DS at each intersection by driving the column electrodes (Y1' to Yn') in synchronization with the timing of sequentially driving the row electrodes.
Many LCD segment DS with fewer drive signals
can be displayed. Furthermore, as a property of liquid crystal display, as shown in Figure 2, display contrast depends on the effective value of the driving voltage applied to the liquid crystal segment.For example, in the same figure, the driving voltage applied to the lighting liquid crystal segment Display is performed based on the difference between the effective value V _ON of , and the effective value V _pff of the driving voltage applied to the non-lit liquid crystal segment. In dynamic driving, increasing the number of row electrodes reduces the difference between the effective value of the driving voltage applied to the lit liquid crystal segment and the effective value of the driving voltage applied to the non-lit liquid crystal segment, which improves display quality. descend. Therefore, in dynamic driving, 4 time division and 3 time division dynamic driving are mainly used as time division numbers that can save the number of drive terminals of the liquid crystal display driving device and do not degrade the display quality. In 4 time division and 3 time division dynamic driving, the voltages for driving the liquid crystal display are Vo, 2/3Vo,
It is customary to drive a liquid crystal display using the 1/3 bias voltage averaging method using four values of 1/3 Vo and O to perform a predetermined display. In the 1/3 bias voltage averaging method, the voltage to drive the liquid crystal display is
Since four values of Vo, 2/3Vo, 1/3Vo, and O are required, four-value voltages are generated by dividing resistors as shown in FIG. In such a case, the voltage
A current of Vo/3R always flows between Vo and ground, which hinders the low power consumption that is an advantage of liquid crystal displays. Therefore, if the dividing resistor is made larger, the power consumed through the dividing resistor will be reduced, but on the other hand, it may become impossible to drive the liquid crystal segments sufficiently, or if other voltage supply devices are used separately from the dividing resistor. Problems arise, such as the need for Therefore, as shown in Figure 4, a voltage of 1/2Vo is taken from the middle of batteries E1 and E2 connected in series.
There is a method of driving a liquid crystal display using three values: Vo, 1/2Vo, and O. In this way, the liquid crystal segments can be sufficiently driven, and the power consumed by the dividing resistors can be completely prevented, thereby promoting low power consumption in the liquid crystal display. Fifth
The figure shows an example of wiring for a liquid crystal display driven by three-time division dynamic drive.
Figure 6 shows an example of the drive voltage waveform obtained by the 3-bias voltage averaging method, and the drive voltage waveform when the liquid crystal drive voltage is set to three values (Vo, 1/2Vo, O) as shown in Figure 4. An example is shown in FIG. In FIGS. 6 and 7, X1, X2, X3 and Y1, Y2 are
FIG. 5 is an example of the driving voltage applied to the row electrodes X1', X2', X3' and the column electrodes Y1', X2', and X2-Y1 is an example of the driving voltage waveform applied to the lighting liquid crystal segment. X1-Y1 and X2-Y2 are examples of driving voltage waveforms applied to non-lit liquid crystal segments, and are applied to liquid crystal segments 1 and 5 in FIG. 5. Table 1 shows the effective values of the driving voltages applied to the lighting liquid crystal segments and non-lighting liquid crystal segments in FIGS. 6 and 7.

[Table] As can be seen from Table 1, when a liquid crystal display is driven by three time-division dynamic driving using the three values of Vo, 1/2Vo, and O as the driving voltage, there are two lighting liquid crystal segments and one non-lighting liquid crystal segment. The difference in the effective value of the driving voltage applied to the lighting liquid crystal segment becomes very small,
In Figure 2, this means that the difference between V _pff and V _ON becomes very narrow, the contrast difference between the lit liquid crystal segment and the non-lit liquid crystal segment almost disappears, and the display quality deteriorates significantly. This has the disadvantage that it becomes almost meaningless as a display device. The purpose of the present invention is to use a three-value liquid crystal drive voltage (Vo, 1/2) in an application field that requires lower power consumption.
Vo, O), without impairing display quality.
Performs liquid crystal display, and also maintains temperature margin for display quality.
In application fields where a wider voltage margin is required, four levels of liquid crystal drive voltage (Vo, 2/3Vo, 1/3Vo,
O) It is an object of the present invention to provide a highly versatile liquid crystal display driving device capable of performing liquid crystal display using the 1/3 bias voltage averaging method. The liquid crystal display driving device according to the present invention has a driving voltage input terminal to which four driving voltage values are inputted and a driving voltage input terminal to which three driving voltage values are inputted as a common terminal under the control of a control circuit. It becomes possible to drive a liquid crystal display with a drive voltage of a certain value,
Provides a liquid crystal display driver suitable for CMOS integrated circuits. According to the present invention, in a liquid crystal display driving device that drives a liquid crystal display constituted by row electrodes and column electrodes, a plurality of driving voltages include first and second high-level voltages, first and second high-level voltages, and a plurality of driving voltages. row electrode and column electrode driving means that has a low level voltage of level voltage and low level voltage,
The row electrode and column electrode driving means includes row electrode and column electrode voltage selection means for supplying the row electrode and column electrode voltage selection means, and control means for controlling the column electrode voltage selection means based on a state control signal, and the state control signal is set to one state. In this case, the separate electrode driving means, corresponding to the state indicating means, outputs a first high level voltage and a first low level voltage, or a second high level voltage and a second low level voltage. and supplied as a low level voltage by the column electrode voltage selection means,
When the state control signal is in the other state, the column electrode voltage selecting means supplies only the first high level voltage and the second low level voltage to the column electrode driving means as high level voltages and low level voltages. A liquid crystal display driving device is obtained. It is also effective to further provide a detection means for detecting the potential difference between the second high-level voltage and the first low-level voltage in the above-mentioned driving device, and to operate the detection signal from the detection means as the state control signal. . An embodiment of the present invention will be described below with reference to FIG. This embodiment is a liquid crystal display driving device that performs three time division dynamic driving, and its configuration will first be explained. In FIG. 8, the output of the ternary counter 5 is decoded by the decoder 6,
The outputs 8-1, 8-2, 8-3 of the decoder 6 are input to exclusive ORs 2-1, 2-2, 2-3, respectively, and the output 8-1 of the decoder 6 is input to the switching element. The output 8-2 of the decoder 6 controls the switching elements 1-20, 1-23, 1-28, and the output 8-3 of the decoder 6 controls the switching elements 1-19, 1-22, and 1-27. Element 1-2
1, 1-24, and 1-29. Switching elements (1-1 to 1-2) shown in the same figure
9) is when the control signal is “1” (High level),
It becomes a conductive state, and becomes an open state when it is “0” (Low level). The ternary counter 5 inverts the output 9 of the flip-flop circuit 7 every time it counts three. The output 9 of the flip-flop circuit 7 is the exclusive OR circuit 2-1, 2-2, 2-3, 2-4, 2-
5, 2-6, AND circuit 16-1, and OR circuit 15-2, and switching element 1-
1 and 1-3, and is input to an inverter circuit 3-4. The output of the inverter circuit 3-4 is
It controls switching elements 1-2 and 1-4 and is input to an AND circuit 16-2 and an OR circuit 15-1. The output of the exclusive OR circuit 2-1 controls the switching element 1-10 and is input to the inverter circuit 3-1, and the output of the inverter circuit 3-1 controls the switching element 1-9. The output of the exclusive OR circuit 2-2 controls the switching element 1-8 and is input to the inverter circuit 3-2, and the output of the inverter circuit 3-2 controls the switching element 1-7. The output of the exclusive OR circuit 2-3 controls the switching element 1-6 and is input to the inverter circuit 3-3, and the output of the inverter circuit 3-3 controls the switching element 1-6.
-Control 5. Memory circuit 4-1, 4-2, 4-
3 has a 3-bit configuration, and each 3 bits is a switching element 1-19, 1-20, 1-21, or 1-22, 1-23, 1-24, or 1-27, 1-28, 1. -29, respectively, and exclusive OR circuits 2-4, 2-
5, 2-6 is input. Exclusive OR circuit 2-
The output of 4 controls the switching element 1-15 and is input to the inverter circuit 3-5, and the output of the inverter circuit 3-5 controls the switching element 1-15.
-16 is controlled. The output of the exclusive OR circuit 2-5 controls the switching element 1-17 and is input to the inverter circuit 3-6, and the output of the inverter circuit 3-6 controls the switching element 1-1.
Control 8. The exclusive OR circuit 2-6 controls the switching element 1-25 and is input to the inverter circuit 3-7, and the output of the inverter circuit 3-7 controls the switching element 1-26.
In addition, the drive voltage input terminals V0, V1, V2, and V3 are connected to four sets (Vo, 2/3Vo, 1/3
A voltage of Vo, O) (unit: volt V) or a three-value voltage (Vo, 1/2Vo, O) as shown in FIG. 4 is applied. In FIG. 8, the control line 14,
OR circuit 15-1, 15-2 and AND circuit 16
-1, 16-2 are control circuits added according to the present invention, and the control line 14 is an OR circuit 15-1, 15-
2 and the inverter circuit 3-8, and the output of the inverter circuit 3-8 is input to the AND circuit 16-1,
It is input in 16-2. OR circuit 15-1,
15-2, AND circuits 16-1, 16-2 are switching elements 1-11, 1-12, 1, respectively.
-13 and 1-14 are controlled. The control line 14 has four driving voltage values, which are fixed to "0" when driving the liquid crystal display by the 1/3 bias voltage averaging method, and the OR circuit 15-2 and the AND circuit 16-1 are flip-flop circuits. Also, the OR circuit 15-1 and AND circuit 16-2 are determined by the output of the inverter circuit 3-4, so when the output 9 of the flip-flop circuit 7 is "0", the switching Elements 1-11 and 1-13 become conductive, the conductive wire 12 becomes the voltage of the drive voltage input terminal V3, and the conductor 13 becomes the voltage of the drive voltage input terminal V1. Output 9 of flip-flop circuit 7 is “1”
At this time, the switching elements 1-12, 1-14 become conductive, and the conductor 12 connects to the drive voltage input terminal V.
2 voltage, and the conductor 13 is connected to the drive voltage input terminal V
The voltage becomes 0. Further, when driving a liquid crystal display using three driving voltage values, the control line 14 is fixed to "1", and at this time, the switching element 1-1 is always
1, 1-14 become conductive, and Vo, 1/2
The voltages Vo and O are applied to the terminals V ₃ -V ₀ as shown in FIG. 4, the conductor 12 becomes the voltage of the drive voltage input terminal V3, and the conductor 13 becomes the voltage of the drive voltage input terminal V0. Note that X1, X2, and X3 in Fig. 8 are
Drives the row electrodes X1', X2', and X3' in the figure, and
Y ₁ , Y _{2 .} . . Y _o are the column electrodes Y ₁ ′, Y ₂ ′ . . . in FIG.
Drive Y _o ′. Next, the specific operation of the present invention will be explained.As shown in FIG.
Turn on 4 and 6 (shaded area) LCD segment 1,
An embodiment of the present invention will be described in detail, taking as an example a case where lights 3 and 5 are not lit. Therefore, in FIG. 8, the memory circuits 4-1 and 4-2 have (0,
1,0), (1,0,1) display information is stored. First of all, the control line 14, the OR circuits 15-1, 15-2, and the AND circuits 16-1, 1 according to the present invention.
In 6-2, the control line 14 is fixed to "0",
The liquid crystal drive input terminals V0, V1, V2, and V3 have
Four values (0, 1/3Vo, 2/3Vo,
The case where the voltage (Vo) is input will be explained. Since the control line 14 is "0", OR circuits 15-1, 15-2 and AND circuits 16-1, 1
The output of the flip-flop circuit 7 or the output of the inverter circuit 3-4 determines the output of the switching element 1.
-11, 1-14, 1-12, and 1-13 are controlled. FIG. 9 shows outputs 8-1, 8-2, 8-3 of a decoder 6 that decodes the output of the ternary counter 5.
The timing chart of the output 9 of the flip-flop circuit 7 and the timing chart of the output 9 of the flip-flop circuit 7 are shown. The outputs 8-1, 8-2, 8-3 of the decoder 6 are sequentially selected as "1", and the output 9 of the flip-flop circuit 7 is selected as the output 8-1, 8-2, 8-3 of the decoder 6.
3 is inverted each time it is selected. Therefore, the output 9 of the flip-flop circuit 7 is "0".
(periods t ₁ , t ₂ , t ₃ in FIG. 9), the switching elements 1-2, 1-4, 1-11, 1-13 are in a conductive state, and the conductor 10 is 2/3Vo (V ), conductor 11
becomes O(V), and conductor 12 is Vo, conductor 13
becomes 1/3Vo. Also, the flip-flop circuit 7
Since the output 9 of is "0", the exclusive OR circuits 2-1, 2-2, 2-3, 2-4, 2-5, 2-
6 outputs the other input signal as is. In FIG. 9, at timing t ₁ , the output 8-1 of the decoder 6 is "1", and the output 8-1 of the decoder 6 is "1".
Since 2, 8-3 are "0", switching elements 1-5, 1-7, 1-10 are in a conductive state,
0, 2/3Vo, 2/3 for X1, X2, X3 respectively
Vo is output, and switching elements 1-19,
Since 1-22 becomes conductive, the memory circuit 4-
1 and 4-2 are input to exclusive OR circuits 2-4 and 2-5, switching elements 1-16 and 1-17 become conductive, and Y
1/3Vo and Vo are output to 1 and Y2, respectively. Next, at timing _t2 , the output 8-2 of the decoder 6 is "1", and the outputs 8-1, 8-3 of the decoder 6
is “0”, switching elements 1-5,
1-8, 1-9 become conductive, and X1, X2,
X3 outputs 2/3Vo, 0, and 2/3Vo, respectively, and since the switching elements 1-20 and 1-23 become conductive, the memory circuits 4-1 and 4-2 output "1" and 2/3Vo, respectively. “0” is selected, switching elements 1-15, 1-18 become conductive, and Y
1 and Y2 output Vo and 1/3Vo, respectively. Next, at timing _t3 , the output 8-3 of the decoder 6 is "1", and the outputs 8-1, 8- of the decoder 6 are "1".
Since 2 is "0", switching element 1-
6, 1-7, 1-9 become conductive, and X1,
2 and X3 output 2/3Vo (V), 2/3Vo, and 0, respectively, and switching elements 1-21 and 1-2
4 becomes conductive, "0" and "1" of memory circuits 4-1 and 4-2 are selected, respectively, switching elements 1-16 and 1-17 become conductive, and Y
1 and Y2 output 1/3Vo and Vo, respectively. Next, when the output 9 of the flip-flop circuit 7 is "1" (periods t ₁ ', t ₂ ', t ₃ ' in FIG. 9), the switching elements 1-1, 1-3, 1-12, 1 -1
4 becomes conductive, conductor 10 becomes Vo, conductor 11
becomes 1/3Vo, and conductor 12 becomes 2/3Vo, conductor 13
becomes 0. Also, since the output of the flip-flop circuit 7 is "1", the exclusive OR circuits 2-1,
2-2, 2-3, 2-4, 2-5, and 2-6 invert the other input signal and output it. That is, at the timing t ₁ ' in FIG. 9, the outputs of the decoder 6 8-1, 8-2, and 8-3 are the same as the timing t ₁ , and the exclusive OR circuits 2-1, 2-2, 2-3, 2-4, 2-
5 inverts the input signal, switching elements 1-6, 1-8, 1-9 and 1-1
5, 1-18 become conductive, and X1, X2, X
3 is Vo, 1/3Vo, 1/3Vo, and Y1, respectively.
Y2 outputs 2/3Vo and 0, respectively. At the timing t ₂ ', the input signal is also inverted by the exclusive OR circuits 2-1, 2-2, 2-3, and 2-4, so the switching element 1-
6, 1-7, 1-10 and 1-16, 1-17 are in a conductive state, and X1, X2, and X3 are each 1/
3Vo, Vo, 1/3Vo, and Y1, Y2 output 0, 2/3Vo, respectively. At the timing t ₃ ', switching element 1-
Since 5, 1-8, 1-10 and 1-15, 1-18 are in a conductive state, X1, X2, X3 are 1/3Vo, 1/3Vo, Vo, respectively, and Y1, Y2 are
2/3Vo and 0 are output respectively. As described above, when the control line 14 is set to "0", the liquid crystal display driving device shown in FIG.
As described above, the drive voltage waveforms of 1, X2, X3 and Y1, Y2 are as shown in FIG. Furthermore, the 6th
t ₁ to t ₃ ' in the figure indicate the same timing as t ₁ to t ₃ ' in FIG. 9, respectively. Second, the control line 14 is fixed to "1", and the fourth
A case where three voltages (Vo, 1/2Vo, 0) are input as shown in the figure will be explained. control line 14
is “1”, so the OR circuit 15-1, 15-
The output of the AND circuit 16-1 and 16-2 is forced to "1", and the output of the AND circuits 16-1 and 16-2 is forced to "0".
Therefore, regardless of the output 9 of the flip-flop circuit 7, the conductor 12 becomes Vo and the conductor 13 becomes 0. or,
When the output 9 of the flip-flop circuit 7 is “0”,
Since the switching elements 1-2 and 1-4 become conductive, the conductor 10 becomes 1/2Vo and the conductor 11 becomes 0. In FIG. 8, conductors 10, 11, 12, 13
Since the other operations are exactly the same as described above except for the state _of
6 and 17 become conductive, X1, X2, and X3 output 0, 1/2Vo, and 1/2Vo, respectively, and Y1 and Y2 output 0 and Vo, respectively. At the timing of _t2 , switching element 1-
5, 1-8, 1-9 and 1-15, 1-18 are in conduction state, so X1, X2, X3 are 1/2Vo, 0, 1/2Vo, respectively, and Y1, Y2 are respectively
Vo,0 is output. At timing _t3 , switching element 1-
6, 1-7, 1-9 and 1-16, 1-17 become conductive, so X1, Vo is output. Next, when the output of the flip-flop circuit 7 is "1", the switching elements 1-1, 1-3
Since it is in a conductive state, the conductor 10 is Vo, the conductor 1
1 becomes 1/2Vo. Further, the conducting wire 12 remains at Vo, and the conducting wire 13 remains at 0. At the timing of t ₁ ', switching element 1-
6, 1-8, 1-9 and 1-15, 1-18 become conductive, so X1, X2, X3 are Vo, 1/2Vo, 1/2Vo are Vo, respectively ,0 are output. At the timing t ₂ ', switching element 1-
6, 1-7, 1-10 and 1-16, 1-17
are in a conductive state, X1, X2, and X3 output 1/2Vo, Vo, and 1/2Vo, respectively, and Y1 and Y2 output 0 and Vo, respectively. At the timing t ₃ ', switching element 1-
5, 1-8, 1-10 and 1-15, 1-18
are in a conductive state, X1, X2, and X3 output 1/2Vo, 1/2Vo, and Vo, respectively, and Y1 and Y2 output Vo and 0, respectively. From the above, in FIG. 8, the control line 14 is set to "1" and the liquid crystal drive voltage is set to three values (Vo, 1/
2Vo, 0), drive voltages of X1, X2, X3 and Y1, Y2 are obtained as shown in FIG. X1-Y1 is the driving voltage applied to the non-lighting liquid crystal segment 1 in FIG. 5, and X2-Y1 is the driving voltage applied to the lighting liquid crystal segment 2. The effective values of the driving voltages applied to the lighting liquid crystal segment and the non-lighting liquid crystal segment in FIG. 10 are shown in Table 2 in comparison with FIGS. 6 and 7. Table 2
As can be seen from Figure 8, three values (Vo, 1/2Vo, 0) are input as the liquid crystal drive voltage,
When the control line 14 is set to "1", good display quality can be obtained, although the difference in effective values is slightly smaller than in the example shown in FIG. 6 using the 1/3 bias voltage averaging method. I understand.

[Table] Furthermore, as shown in FIG. 11, a detector 17 is provided to detect the potential difference between the drive voltage input terminals V1 and V2.
When no potential difference is detected, the control line 14 is set to “1”.
If the control line 14 is configured to be set to "0" when the potential difference between the drive voltage input terminals V1 and V2 is detected, the control line 14 is automatically set to "0" by the voltage applied to the drive voltage input terminals. can be controlled without fixing the control line 14 from the outside.
The liquid crystal display can be driven using a predetermined driving voltage. In particular, in a liquid crystal display driving device that can perform arbitrary time-division dynamic driving, a control circuit is provided to provide a control line and control liquid crystal driving voltage selection.
Even in 4 time division or 2 time division dynamic driving, 1/3 bias voltage averaging method or
The liquid crystal display can also be driven using a three-value liquid crystal drive voltage (Vo, 1/2Vo, 0) without degrading the display quality. Therefore, according to the present invention, when driving a liquid crystal display by arbitrary time-division dynamic driving using a liquid crystal display driving device, a control line is provided and a control circuit for controlling liquid crystal driving voltage selection is added. However, in application fields that require lower power consumption, three levels of liquid crystal drive voltage (Vo, 1/2Vo,
0) allows liquid crystal display to be performed without deteriorating the display quality, and in application fields where a wide temperature margin or voltage margin is required for display quality, the four-value liquid crystal drive voltage (Vo, 2/3Vo ,1/3
By using the 1/3 bias voltage averaging method at Vo, 0), it is possible to provide a highly versatile liquid crystal display driving device that can perform liquid crystal display, and its effects are very large.

[Brief explanation of drawings]

The first is a diagram showing the wiring of a dynamically driven liquid crystal display, the second is a diagram showing the effective voltage versus display contrast characteristics in a liquid crystal display, the third is a diagram showing an example of creating a four-value voltage using dividing resistors, Figure 4 is 3
Figure 5 is a diagram showing the creation of value voltages.
The figure shows an example of the row electrode and column electrode drive voltage waveforms using the 1/3 bias voltage averaging method.
A diagram showing an example of a driving voltage waveform when driving a liquid crystal display using three values (Vo, 1/2Vo, 0) in a time-division dynamic driving liquid crystal display driving device. A diagram showing the display drive device, FIG. 9 shows the outputs 8-1, 8- of the decoder 6.
2, 8-3 and the output 9 of the flip-flop circuit 7
Figure 10 shows the timing chart of the 8th
In the figure, three values are input as the liquid crystal drive voltage,
A diagram showing an example of a driving voltage waveform when driving a liquid crystal display by setting the control line 14 to "1", and FIG. It is a figure which shows an example. 1-1 to 1-26...Switching element, 2-
1 to 2-6...Exclusive OR circuit, 3-1 to 3-
8... Inverter circuit, 4-1 to 4-3... Memory circuit, 5... Ternary counter, 6... Decoder, 7
...Flip-flop circuit, 8-1 to 8-3...
Output of decoder 6, 9... Output of flip-flop circuit 7, 10, 11, 12, 13... Conductor, 1
4...Control line, 15-1, 15-2...OR circuit, 16-1, 16-2...AND circuit, V0~
V3...LCD drive voltage input terminal, X1~X3...
Row electrode drive terminal, Y1- _Yo ...column electrode drive terminal.

Claims (1)

[Claims] 1. In a liquid crystal display driving device configured as an integrated circuit for driving a liquid crystal display comprising row electrodes and column electrodes, a row electrode driving means for driving first to fourth voltage terminals and the row electrodes; state indicating means for alternately instructing the state; and voltages at the second and fourth voltage terminals when the state indicating means is in the first state, and voltages at the first and fourth voltage terminals when the state indicating means is in the second state. Row voltage selection means for supplying the voltage of the third voltage terminal to the row electrode driving means as a driving voltage;
the first and second conductive wires and the first conductor of the status indicating means;
The voltages at the first and third voltage terminals are applied to the first and second conductive wires in response to the state, and the voltages at the second and fourth voltage terminals are applied to the first and second conductive wires in response to the second state, respectively. column voltage selection means to supply; and column electrode driving means for outputting one voltage of the first and second conducting wires to the column electrode according to the state of the state indicating means and display information; The voltage selection means includes first and second switch means connected respectively between the first and second voltage terminals and the first conductor, and between the third and fourth voltage terminals and the second conductor. third and fourth switch means respectively connected between the conductor wires of the switch means; and third and fourth switch means connected respectively between the conductors of the second and fourth switch means are made conductive in response to the second state of the state indicating means, and when the state control signal is in the other state, the state of the state indicating means is changed; has a control circuit which independently makes the first and fourth switch means conductive, and when the state control signal is in one of the states, the first to fourth voltage terminals have a substantially equal potential difference. First to fourth voltages having successively smaller values are respectively applied to the row electrodes, and the second and fourth voltages are applied to the row electrodes.
a first state in which one of the voltages is output and one of the first and third voltages is output to the column electrode, and one of the first and third voltages is output to the row electrode; The second electrode is connected to the column electrode.
and a second state in which one of the fourth voltages is output are alternately repeated, and when the state control signal is in the other state, the same intermediate voltage is applied to the second and third voltage terminals. The first voltage and the fourth voltage are applied to the first and fourth voltage terminals, respectively, the intermediate voltage has a value approximately intermediate between the first and fourth voltages, and the intermediate voltage is applied to the row electrode. is a third state in which one of the first voltage and the intermediate potential is output and one of the first voltage and the fourth voltage is output to the column electrode, and the intermediate voltage and the fourth voltage are output to the row electrode. A driving device for a liquid crystal display device, wherein a fourth state in which one of the fourth voltages is outputted and one of the first and fourth voltages is outputted to the column electrodes is alternately repeated.