KR100213255B1 - LCD drive micom bias boltage generation circuit - Google Patents

Abstract

A liquid crystal display bias generation circuit of a microcomputer for driving a liquid crystal display adopting a resistance method as a method of dividing a liquid crystal display bias voltage, comprising: a plurality of liquid crystal voltage terminals, a transistor, first resistance elements, A liquid crystal display bias generating circuit is disclosed. A plurality of liquid crystal voltage terminals output a bias applied to the liquid crystal. The transistor has a switching characteristic capable of varying a current driving ability according to an internal resistance to be connected and is controlled by a liquid crystal display control signal. The first resistance elements are connected in series to each other, and are respectively connected between a plurality of liquid crystal voltage terminals. The first switching resistance portion is composed of one second resistance element and one switching element which are connected in series, and are connected in parallel to the corresponding first resistance elements, respectively. According to the present invention, the current driving capability can be switched according to the size of the liquid crystal display panel to be driven by varying the internal resistance of the liquid crystal display bias voltage generating circuit.

Description

[0001] The present invention relates to a bias voltage generating circuit for a microcomputer for driving a liquid crystal display,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display bias generating circuit of a microcomputer for driving a liquid crystal display employing a resistance method as a method of dividing a liquid crystal display bias voltage applied to a liquid crystal, And a display bias generation circuit.

In a liquid crystal display driving bias voltage generating circuit of a microcomputer for driving a liquid crystal display (LCD), there are a resistance method and a capacitor method according to a method of dividing a liquid crystal display driving bias voltage.

The capacitor method is applied to a set in which the DC current consumption is extremely small and the current consumption is low, but since the capacitor must be added to the outside of the capacitor, the set makers who manufacture the liquid crystal display driving system using the chip Cost burden is large.

The resistance method uses a resistor inside, so the circuit is simple, easy to design, and simple to use.

However, there is a disadvantage that the direct current is always consumed in the liquid crystal display bias operation. However, even in such a case, if the internal resistance is made sufficiently large, a negligible consumption current flows, which is not a problem in use.

1 is a circuit diagram of a conventional bias voltage generating circuit of a microcomputer for driving a liquid crystal display.

1, the first to fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, VLC5, the one MOSFET Q and the first to fifth resistive elements R1, R2, R3, R4, R5). The first to fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, and VLC5 are for applying a bias to the liquid crystal. One of the MOSFETs Q has a drain connected to the power supply terminal VCC and a source connected to the first liquid crystal voltage terminal VLC1 and a liquid crystal display control signal LCDON as an input to the gate. 5 resistors R1, R2, R3, R4 and R5 are connected in series and connected between the first to fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, VLC5. Here, the first through fifth resistance elements R1, R2, R3, R4, and R5 have the same values to make the voltage difference applied across the liquid crystal the same. And has a sufficiently large value in order to reduce the DC current consumed in the liquid crystal display bias operation.

However, if a conventional microcomputer for driving a liquid crystal display is used for a game machine or a data bank that requires a large size of a panel of a liquid crystal display, the current of the liquid crystal display due to an increase in the internal load of the liquid crystal display panel The driving ability is lowered and the product quality is lowered. As a method for overcoming such a problem, a method of increasing the driving capability of the liquid crystal bias voltage generating circuit by reducing the internal resistance of the liquid crystal bias voltage generating circuit by connecting the resistance elements outside the microcomputer for driving the liquid crystal display has been used.

2 is an application circuit diagram of a conventional bias voltage generating circuit of a microcomputer for driving a liquid crystal display showing an example of such a method.

Referring to FIG. 2, the first through fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, VLC5, one MOSFET Q, the first through fifth resistive elements R1, R2, R3, , R5), and first to fifth external resistive elements (R6, R7, R8, R9, R10). The first to fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, and VLC5 are for applying a bias to the liquid crystal. One of the MOSFETs Q has a drain connected to the power supply terminal VCC and a source connected to the first liquid crystal voltage terminal VLC1 and a liquid crystal display control signal LCDON as an input to the gate. 5 resistors R1, R2, R3, R4 and R5 are connected in series between the first through fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, VLC5. The first to fifth external resistive elements R6, R7, R8, R9 and R10 are connected in series and are connected between the first to fifth external resistor connection terminals N1, N2, N3, N4 and N5 And is connected in parallel with each of the corresponding first through fifth resistance elements R1, R2, R3, R4, and R5. The first through fifth resistive elements R1, R2, R3, R4 and R5 and the first through fifth external resistive elements R6, R7, R8, R9 and R10 are applied to both ends of the liquid crystal Have the same values for each other to make the voltage difference the same.

The first through fifth external resistor elements R6, R7, R8, R9, and R10 may be further connected to the external terminals using the first through fifth external resistor connection terminals N1, N2, N3, N4, and N5. The current driving capability of the liquid crystal display can be increased.

However, there is a limit to the improvement of the driving ability by such a method, and there is a disadvantage that the user must connect the resistance elements from the outside.

Therefore, it is an object of the present invention to provide a liquid crystal display bias voltage generating circuit which can vary an internal resistance in a liquid crystal display bias voltage generating circuit of a driving microcomputer using a resistance method.

It is another object of the present invention to provide a liquid crystal display bias voltage generating circuit of a microcomputer for driving a liquid crystal display using a resistance type liquid crystal display driving bias voltage capable of switching a current driving capability according to a size of a liquid crystal display panel to be driven Circuit.

1 is a circuit diagram of a conventional bias voltage generating circuit of a microcomputer for driving a liquid crystal display.

2 is an application circuit diagram of a conventional bias voltage generating circuit of a microcomputer for driving a liquid crystal display.

3 is a circuit diagram of a bias voltage generating circuit of a microcomputer for driving a liquid crystal display according to the first embodiment of the present invention.

4 is an application circuit diagram of a bias voltage generating circuit of a microcomputer for driving a liquid crystal display according to a second embodiment of the present invention.

5 is a circuit diagram of a bias voltage generating circuit of a microcomputer for driving a liquid crystal display according to a third embodiment of the present invention.

6 is an application circuit diagram of a bias voltage generating circuit of a microcomputer for driving a liquid crystal display according to a fourth embodiment of the present invention.

7 is an application circuit diagram of a bias voltage generating circuit of a microcomputer for driving a liquid crystal display according to a fifth embodiment of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

VCC, GND: Power supply, Ground terminal, Q: Transistor

VLC1 to VLC5: liquid crystal voltage terminals

N1 to N5: additional external resistor connection terminals

R1 to R20: Resistance elements

SW1 to SW10: switching elements

Z1 to Z10: switching resistors

According to an aspect of the present invention, a liquid crystal display bias voltage generating circuit includes a plurality of liquid crystal voltage terminals, a transistor, first resistance elements, and switching resistors. Here, the plurality of liquid crystal voltage terminals output a bias applied to the liquid crystal, and the transistor has a switching characteristic capable of varying a current driving ability according to an internal resistance connected thereto, and is controlled by a liquid crystal display control signal . The first resistance elements are connected to each other in series and are connected between a plurality of liquid crystal voltage terminals. The first switching resistance unit is composed of one second resistive element and one switching element connected in series, and is connected in parallel to the corresponding first resistive elements.

The present invention will now be described in detail with reference to the accompanying drawings.

3 is a circuit diagram of a bias voltage generating circuit of a microcomputer for driving a liquid crystal display according to the first embodiment of the present invention.

Referring to FIG. 3, the first through fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, VLC5, one MOSFET Q, the first through fifth resistive elements R1, R2, R3, , R5, and first to fifth switching resistors Z1, Z2, Z3, Z4, and Z5. The first to fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, and VLC5 output a bias voltage applied to the liquid crystal. One of the MOSFETs Q has a drain connected to the power supply terminal VCC and a source connected to the first liquid crystal voltage terminal VLC1 and a liquid crystal display control signal LCDON as an input to the gate. 5 resistors R1, R2, R3, R4 and R5 are connected in series and connected between the first to fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, VLC5 , The first to fifth switching resistors Z1, Z2, Z3, Z4, and Z5 are each formed by one additional internal resistance element and one switching element connected in series and are connected in series to each other, R2, R3, R4, and R5 corresponding to the terminals VLC1, VLC2, VLC3, VLC4, and VLC5, respectively. The first through fifth switching devices SW1, SW2, SW3, SW4, and SW5 constituting the first through fifth switching resistors Z1, Z2, Z3, Z4, and Z5 receive the switching control signal STRONG ). The liquid crystal display control signal (LCDON) and the switching control signal (STRONG) can be generated according to the manufacturer's choice of manufacturing a liquid crystal display system using a microcomputer.

R2, R3, R4, and R5 and first to fifth switching resistors Z1, Z2, Z3, and Z4 to generate the same potential difference applied across the liquid crystal R5, R6, R7, R8, R9, and R10 constituting the first to fifth internal resistance elements Z1, Z5 have the same value.

As described above, the first to fifth additional internal resistance elements R6, R7, R8, R9 and R10 and the first to fifth switching elements SW1, SW2, SW3, SW4, SW5 Therefore, the current driving capability of the liquid crystal driving bias voltage generating circuit can be varied. Therefore, it is possible to adjust the current driving ability of the liquid crystal driving bias voltage generating circuit according to the size of the liquid crystal display panel Can be used.

4 is an application diagram of a bias voltage generating circuit of a microcomputer for driving a liquid crystal display according to a second embodiment of the present invention.

Referring to FIG. 4, the first to fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, VLC5, one MOSFET Q, first through fifth resistance elements R1, R2, R3, R5, the first to fifth switching resistors Z1, Z2, Z3, Z4, and Z5, and the first to fifth external resistors R11, R12, R13, R14, and R15. The first to fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, and VLC5 output a bias voltage applied to the liquid crystal. One of the MOSFETs Q has a drain connected to the power supply terminal VCC and a source connected to the first liquid crystal voltage terminal VLC1 and a liquid crystal display control signal LCDON as an input to the gate. 5 resistors R1, R2, R3, R4 and R5 are connected in series and connected between the first to fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, VLC5 , The first to fifth switching resistors Z1, Z2, Z3, Z4, and Z5 are each formed by one additional internal resistance element and one switching element connected in series and are connected in series to each other, R2, R3, R4, and R5 corresponding to the terminals VLC1, VLC2, VLC3, VLC4, and VLC5, respectively. The first to fifth external resistor elements R11, R12, R13, R14 and R15 are connected in series and are connected to the first to fifth external resistor connection terminals N1, N2, N3, N4, R2, R3, R4, and R5 are connected in parallel. Here, as in the above embodiment, the first to fifth switching resistors R1, R2, R3, R4, The first through fifth switching elements SW1, SW2, SW3, SW4, and SW5 constituting the first to fourth switching elements Z1, Z2, Z3, Z4 and Z5 are controlled by the switching control signal STRONG. In addition, the liquid crystal display control signal (LCDON) and the switching control signal (STRONG) may be generated according to the manufacturer's choice of manufacturing a liquid crystal display system using a microcomputer.

R2, R3, R4, and R5, and the first to fifth switching resistors Z1, Z2, Z3, Z4, and Z5 to equalize the potential difference applied across the liquid crystal, R5, R6, R7, R8, R9, and R10, and the first to fifth external resistive elements R11, R12, R13, R14, They have the same value.

As described above, the first to fifth additional internal resistance elements R6, R7, R8, R9 and R10 and the first to fifth switching elements SW1, SW2, SW3, SW4, SW5 And the first to fifth external resistive elements R11, R12, R13, R14 and R15 are connected to the external one, so that the internal resistance of the liquid crystal driving bias voltage generating circuit can be varied as needed Therefore, the current driving capability of the liquid crystal driving bias voltage generating circuit can be further varied, so that the size of the liquid crystal display panel that can be used can be further diversified.

5 is a bias voltage generating circuit diagram of a microcomputer for driving a liquid crystal display according to a third embodiment of the present invention.

5, the first through fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, VLC5, one MOSFET Q, the first through fifth resistive elements R1, R2, R3, R4 Z5, Z5, Z5, Z6, Z7, Z8, Z9, and Z10 of the first to fifth switching resistors Z1, Z2, Z3, Z4, and Z5. The first to fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, and VLC5 output a bias voltage applied to the liquid crystal. One MOSFET Q has a drain connected to the fifth liquid crystal voltage terminal VLC5, a source connected to the ground terminal GND, and a liquid crystal display control signal LCDON as an input to the gate. 5 resistors R1, R2, R3, R4 and R5 are connected in series and connected between the first to fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, VLC5 , The first to fifth switching resistors Z1, Z2, Z3, Z4, and Z5 are each formed by one additional internal resistance element and one switching element connected in series and are connected in series to each other, R2, R3, R4, and R5 corresponding to the terminals VLC1, VLC2, VLC3, VLC4, and VLC5, respectively. The sixth through tenth switching resistors Z6, Z7, Z8, Z9 and Z10 are connected in series with one additional internal resistance element and one switching element connected in series, Z1, Z2, Z3, Z4, and Z5, which correspond to the first to fifth switching resistors VLC1, VLC2, VLC3, VLC4, and VLC5, respectively. The first through fifth switching elements SW1, SW2, SW3, SW4, and SW5 constituting the first through fifth switching resistors Z1, Z2, Z3, Z4, and Z5 are connected to the first switching control signal SW6, SW7, SW8, SW9, and SW10 that are controlled by the first to sixth switching resistors STRONG1 to STR10 and constitute the sixth to tenth switching resistors Z6, Z7, Z8, Z9, and Z10, Is controlled by the second switching control signal STRONG2. The liquid crystal display control signal LCDON and the first and second switching control signals STRONG1 and STRONG2 may be generated according to the manufacturer's choice of manufacturing a liquid crystal display system using a microcomputer.

R2, R3, R4, and R5 and the first to fifth switching resistors Z1, Z2, Z3, Z4, and Z5 to generate the same potential difference applied across the liquid crystal, R7, R8, R9, and R10 and the sixth to tenth switching resistance sections Z6, Z7, Z8, Z9, and Z10 constituting the first to fifth internal resistance elements Z5, The sixth to tenth additional internal resistance elements R11, R12, R13, R14, and R15 having the same value have mutually the same value.

As described above, the first to fifth additional internal resistance elements R6, R7, R8, R9 and R10 and the first to fifth switching elements SW1, SW2, SW3, SW4, SW5 ), Sixth to tenth additional internal resistance elements R11, R12, R13, R14, and R15 and sixth to tenth switching elements SW6, SW7, SW8, SW9, SW10), the internal resistance of the liquid crystal driving bias voltage generating circuit can be varied as needed. Therefore, the current driving ability of the liquid crystal driving bias voltage generating circuit can be varied, Can be used.

6 is an application diagram of a bias voltage generating circuit of a microcomputer for driving a liquid crystal display according to a fourth embodiment of the present invention.

Referring to FIG. 6, the first to fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, VLC5, one MOSFET Q, first through fifth resistance elements R1, R2, R3, Z5, Z6, Z7, Z8, Z9, Z10, and first to fifth switching resistors Z1, Z2, Z3, Z4, And external resistance elements R16, R17, R18, R19, and R20. The first to fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, and VLC5 output a bias voltage applied to the liquid crystal. One of the MOSFETs Q has a drain connected to the power supply terminal VCC and a source connected to the first liquid crystal voltage terminal VLC1 and a liquid crystal display control signal LCDON as an input to the gate. 5 resistors R1, R2, R3, R4 and R5 are connected in series and connected between the first to fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, VLC5 , The first to fifth switching resistors Z1, Z2, Z3, Z4, and Z5 are each formed by one additional internal resistance element and one switching element connected in series and are connected in series to each other, R2, R3, R4, and R5 corresponding to the terminals VLC1, VLC2, VLC3, VLC4, and VLC5, respectively. The sixth through tenth switching resistors Z6, Z7, Z8, Z9 and Z10 are connected in series with one additional internal resistance element and one switching element connected in series, Z1, Z2, Z3, Z4, and Z5, respectively, which correspond to the first to fifth switching resistors VLC1, VLC2, VLC3, VLC4, and VLC5. The first to fifth external resistor elements R16, R17, R18, R19 and R20 are connected in series to each other and are connected to the first to fifth external resistor connection terminals N1, N2, N3, N4, R2, R3, R4, and R5 are connected in parallel, and the first to fifth switching resistors Z1, Z2, and Z4 are connected in parallel with the first to fifth resistive elements R1, R2, R3, The first to fifth switching elements SW1 to SW5 constituting the first to fifth switching elements Z3 to Z5 are controlled by the first switching control signal STRONG1, The sixth to tenth switching elements SW6, SW7, SW8, SW9 and SW10 constituting the parts Z6, Z7, Z8, Z9 and Z10 are controlled by the second switching control signal STRONG2. The liquid crystal display control signal LCDON and the first and second switching control signals STRONG1 and STRONG2 may be generated according to the manufacturer's choice of manufacturing a liquid crystal display system using a microcomputer.

R2, R3, R4, and R5 and the first to fifth switching resistors Z1, Z2, Z3, Z4, and Z5 to generate the same potential difference applied across the liquid crystal, R7, R8, R9, and R10 and the sixth to tenth switching resistance sections Z6, Z7, Z8, Z9, and Z10 constituting the first to fifth internal resistance elements Z5, Z5, The sixth through tenth additional internal resistive elements R11 through R15 and the first through fifth external resistive elements R16 through R20 have the same value I have.

As described above, the first to fifth additional internal resistance elements R6, R7, R8, R9 and R10 and the first to fifth switching elements SW1, SW2, SW3, SW4, SW5 ), Sixth to tenth additional internal resistance elements R11, R12, R13, R14, and R15 and sixth to tenth switching elements SW6, SW7, SW8, SW9, And the first to fifth external resistive elements R16, R17, R18, R19 and R20 are connected to the external resistor elements R10 to R10, so that the internal resistance of the liquid crystal driving bias voltage generating circuit can be varied Therefore, the current driving capability of the liquid crystal driving bias voltage generating circuit can be further varied, so that the size of the liquid crystal display panel that can be used can be further diversified

7 is an application diagram of a bias voltage generating circuit of a microcomputer for driving a liquid crystal display according to a fifth embodiment of the present invention.

Referring to FIG. 7, the first to fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, VLC5, one MOSFET Q, the first through fifth resistive elements R1, R2, R3, R4 Z5, Z6, Z7, Z8, Z9, Z10, and first to fifth switching resistors Z1, Z2, Z3, Z4, And external resistance elements R16, R17, R18, R19, and R20. The first to fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, and VLC5 output a bias voltage applied to the liquid crystal. One of the MOSFETs Q has a drain connected to the power supply terminal VCC and a source connected to the first liquid crystal voltage terminal VLC1 and a liquid crystal display control signal LCDON as an input to the gate. 5 resistors R1, R2, R3, R4 and R5 are connected in series and connected between the first to fifth liquid crystal voltage terminals VLC1, VLC2, VLC3, VLC4, VLC5 , The first to fifth switching resistors Z1, Z2, Z3, Z4, and Z5 are each formed by one additional internal resistance element and one switching element connected in series and are connected in series to each other, R2, R3, R4, and R5 corresponding to the terminals VLC1, VLC2, VLC3, VLC4, and VLC5, respectively. The sixth through tenth switching resistors Z6, Z7, Z8, Z9 and Z10 are connected in series with one additional internal resistance element and one switching element connected in series, Z1, Z2, Z3, Z4, and Z5, respectively, which correspond to the first to fifth switching resistors VLC1, VLC2, VLC3, VLC4, and VLC5. The first to fifth external resistor elements R16, R17, R18, R19 and R20 are connected in series to each other and are connected to the first to fifth external resistor connection terminals N1, N2, N3, N4, R2, R3, R4, and R5 are connected in parallel, and the first to fifth switching resistors Z1, Z2, and Z4 are connected in parallel with the first to fifth resistive elements R1, R2, R3, The first to fifth switching elements SW1 to SW5 constituting the first to fifth switching elements Z3 to Z5 are controlled by the first switching control signal STRONG1, The sixth to tenth switching elements SW6, SW7, SW8, SW9 and SW10 constituting the parts Z6, Z7, Z8, Z9 and Z10 are controlled by the second switching control signal STRONG2. The liquid crystal display control signal LCDON and the first and second switching control signals STRONG1 and STRONG2 may be generated according to the manufacturer's choice of manufacturing a liquid crystal display system using a microcomputer.

R2, R3, R4, and R5 and the first to fifth switching resistors Z1, Z2, Z3, Z4, and Z5 to generate the same potential difference applied across the liquid crystal, R7, R8, R9, and R10 and the sixth to tenth switching resistance sections Z6, Z7, Z8, Z9, and Z10 constituting the first to fifth internal resistance elements Z5, Z5, The sixth through tenth additional internal resistive elements R11 through R15 and the first through fifth external resistive elements R16 through R20 have the same value I have.

As described above, the first to fifth additional internal resistance elements R6, R7, R8, R9 and R10 and the first to fifth switching elements SW1, SW2, SW3, SW4, SW5 ), Sixth to tenth additional internal resistance elements R11, R12, R13, R14, and R15 and sixth to tenth switching elements SW6, SW7, SW8, SW9, And the first to fifth external resistive elements R16, R17, R18, R19 and R20 are connected to the external resistor elements R10 to R10, so that the internal resistance of the liquid crystal driving bias voltage generating circuit can be varied Therefore, the current driving capability of the liquid crystal driving bias voltage generating circuit can be further varied, so that the size of the liquid crystal display panel that can be used can be further diversified

In the liquid crystal display bias generating circuit of the microcomputer for driving the liquid crystal display according to the present invention, the number of the switching resistors is further increased according to the range allowed by the manufacturing technique, thereby further increasing the variability of the driving ability.

The present invention relates to a liquid crystal display bias voltage generating circuit of a microcomputer for driving a liquid crystal display using a resistance method and has an effect of switching a current driving capability according to the size of a liquid crystal display panel to be driven by varying an internal resistance.

Claims (6)

A liquid crystal display bias generating circuit of a microcomputer for driving a liquid crystal display adopting a resistance method as a method of dividing a liquid crystal display bias voltage, A plurality of liquid crystal voltage terminals for outputting bias voltages applied to the liquid crystal; One transistor having a source connected to a power supply terminal, a drain connected to the first liquid crystal voltage terminal, and a liquid crystal display control signal as an input to the gate; A plurality of first resistance elements connected in series to each other and connected between the liquid crystal voltage terminals, respectively; And And a plurality of switching resistors connected in parallel to the corresponding first resistive elements, each of the switching resistive elements being composed of one second resistive element and one switching element connected in series, Microcom's liquid crystal display bias voltage generating circuit. The liquid crystal display of claim 1, further comprising external connection terminals between the plurality of liquid crystal voltage terminals so that the resistance elements can be connected in parallel with the first resistance elements, respectively, And the liquid crystal display bias generation circuit of the microcomputer for driving the liquid crystal display. A liquid crystal display bias generating circuit of a microcomputer for driving a liquid crystal display adopting a resistance method as a method of dividing a liquid crystal display bias voltage, A plurality of liquid crystal voltage terminals for outputting a bias voltage applied to the liquid crystal; One transistor having a source connected to a power supply terminal, a drain connected to the first liquid crystal voltage terminal, and a liquid crystal display control signal as an input to the gate; A plurality of first resistance elements connected in series to each other and connected between the liquid crystal voltage terminals, respectively; A plurality of first switching resistors connected in parallel to the corresponding first resistive elements, each of the first switching resistive elements being composed of one second resistive element and one first switching element connected in series; And And a plurality of second switching resistors connected in parallel to the corresponding one of the first resistors, each of the plurality of second resistors being connected in series with the third resistive element and the second switching element. A liquid crystal display bias voltage generating circuit of a microcomputer for driving a liquid crystal display. The liquid crystal display device according to claim 3, further comprising external connection terminals between the plurality of liquid crystal voltage terminals so that the resistance elements can be connected in parallel with the first resistance elements, And the liquid crystal display bias generation circuit of the microcomputer for driving the liquid crystal display. A liquid crystal display bias generating circuit of a microcomputer for driving a liquid crystal display adopting a resistance method as a method of dividing a liquid crystal display bias voltage, A plurality of liquid crystal voltage terminals for outputting a bias voltage applied to the liquid crystal; One transistor having a source connected to the ground terminal, a drain connected to the fifth liquid crystal voltage terminal, and a liquid crystal display control signal as an input to the gate; A plurality of first resistance elements connected in series to each other and connected between the liquid crystal voltage terminals, respectively; A plurality of first switching resistors connected in parallel to the corresponding first resistive elements, each of the first switching resistive elements being composed of one second resistive element and one first switching element connected in series; And And a plurality of second switching resistors connected in parallel to the corresponding one of the first resistors, each of the plurality of second resistors being connected in series with the third resistive element and the second switching element. A liquid crystal display bias voltage generating circuit of a microcomputer for driving a liquid crystal display. 6. The liquid crystal display of claim 5, further comprising external connection terminals between the plurality of liquid crystal voltage terminals so that the resistance elements can be connected in parallel with the first resistance elements, respectively, And the liquid crystal display bias generation circuit of the microcomputer for driving the liquid crystal display.