JP3160047B2 - Semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a liquid crystal panel driving L
The present invention relates to a semiconductor device having a built-in CD driver.

[0002]

2. Description of the Related Art Conventionally, an LC having a circuit configuration as shown in FIG.
D driver, in order to reduce the current consumption when stopped,
When the timing generator 1 is stopped, the LCD dividing resistor R
₃ , the transistor 7 is turned off so as to cut off the current flowing through R ₂ and R ₁ .

[0003]

However, the conventional LCD driver having the circuit configuration shown in FIG. 2 turns off the transistor 7 when the transistor is stopped, but turns off the N-channel transistor when the transistor 5 or the transistor 6 is stopped while the transistor 5 or 6 is turned on. Therefore, the potential levels of the common terminal COM _n , the segment terminals SEG _n , SEG _{n + 1} , and SEG _{n + 2} are V
LCD cannot be lifted completely to CC level
The common terminal CO
M _n and the segment terminal _{SEG n, SEG n + 1,} SEG
_A potential difference occurs between _{n + 2} . For this reason, there is a drawback that the liquid crystal panel may flicker or cause a thin lighting. SUMMARY OF THE INVENTION An object of the present invention is to eliminate flickering and thin lighting of a liquid crystal panel when an LCD driver is stopped in order to solve such a conventional drawback.

[0004]

In order to solve the above-mentioned problems, the present invention eliminates the potential difference between the common terminal and the segment terminal when the LCD driver is stopped, makes the same potential (VCC level), and causes the liquid crystal panel to flicker and lightly light. Was eliminated.

[0005]

As shown in FIG. 1, when the LCD driver is stopped, the transistor 7 is turned off and the transistor 3 is turned on.
Therefore, even if the transistors 5 and 6 are ON, the common terminal COM _n , the segment terminals SEG _n and SE
Since the potentials of G _{n + 1} and SEG _{n + 2} are raised to the VCC level and the potentials of the common terminal and the segment terminal become the same, flickering and thin lighting of the liquid crystal panel are eliminated.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the semiconductor device according to the present invention will be described below with reference to the drawings. In FIG. 1, the output of a timing generator 1 is a data register 2 and a control circuit 10.
Is input to The output of the control circuit 10 is L
It is input to the CD driver 11. When the LCD driver is stopped, the stop signal ST becomes "1", the timing generator 1 is stopped, the transistor 7 is turned off, and the transistor 3 is turned on by the stop controller 12, so that the transistor 5 or the transistor 6 is stopped and turned on. However, since the potentials of the common terminal COM _n and the segment terminals SEG _n , SEG _{n + 1} and SEG _{n + 2} can be raised to the VCC level, the common terminal COM _n
n , segment terminals SEG _n , SEG _{n + 1} , SEG _{n + 2}
Since there is no potential difference between them and the potential becomes the same (VCC level), the liquid crystal panel does not flicker or does not emit light.

In order to turn off the transistor 7,
Since the current flowing through the LCD dividing resistors R ₃ , R ₂ , and R ₁ is cut, power consumption can be reduced. Note that the data register 2 holds segment information, and the voltage VLCS,
VLC1, VLC2, and VLC3 are voltages for driving the segments.

[0008]

As described above, according to the invention of the semiconductor device, when the LCD driver is stopped, the potential difference between the common terminal and the segment terminal is eliminated by setting the common terminal and the segment terminal to the VCC level. It has the effect of eliminating flickering and faint lighting of the attached liquid crystal panel.

[Brief description of the drawings]

FIG. 1 is a block diagram of a semiconductor device according to the present invention.

FIG. 2 shows a block diagram of a conventional semiconductor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Timing generator 2 Data register 3, 4 P-channel transistor 5, 6, 7 N-channel transistor

Claims (1)

(57) [Claims] An LC for supplying a plurality of voltage levels to a common terminal and a segment terminal of an LCD matrix panel.
A semiconductor device for D drive, and a voltage dividing circuit for connecting a plurality of resistors in series between the power supply terminals, and outputs the divided predetermined level of voltage from the connection point of the resistors, said voltage divider a first switching element connected in series to the circuit, the plurality of second connected between the common terminal and each respective <br/> terminals of said segment terminal said each said connecting point
And a stop signal for stopping the drive of the LCD matrix panel . When the stop signal is input , the first
Off the switching elements of each of the common terminals
And directly connected to one of the power terminals of the segment terminals.
A stopping control circuit for controlling each of the connected second switching elements to be turned on, the semiconductor device for driving an LCD.