JP2000194329A - Voltage transformation control circuit and voltage transformation control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a voltage transformation control circuit which easily and surely transforms the voltage generated by a power circuit. SOLUTION: If output terminals T0 and T1 of an LSI of a power circuit 21 are short-circuited during a driving voltage generation, an electron charge transporting capacitor CC and a voltage holding capacitor C1 are charged up first. Then, the capacitor CC is successively and serially connected to voltage holding capacitors C2 to C4, the capacitors C2 to C4 are successively charged up and one time, doubled, tripled and quadrupled voltages of a reference voltage are generated. If the terminal T0 and a terminal T2 are short circuited, a serial circuit made up with the capacitors C1 and CC and the capacitor C2 are charged up first. Then, the capacitor CC is successively and serially connected to the capacitors C3 and C4 and 1/2 time, one time, 3/2 time and doubled voltages of the reference voltage are generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformation control circuit and a transformation control method for controlling a voltage generated by a power supply circuit, and more particularly to a transformation control circuit for easily and surely switching a voltage generated by a power supply circuit. And a transformer control method.

[0002]

2. Description of the Related Art A power supply circuit of a liquid crystal display device for performing display using liquid crystal boosts a voltage supplied from the outside, divides the boosted voltage by a resistor, and supplies a plurality of voltages for driving the liquid crystal display device. Generate When standardizing the power supply circuit of a liquid crystal display device to reduce the number of parts in the liquid crystal display device, since the drive voltage differs for each liquid crystal display device, the power supply circuit switches the voltage generated by boosting the voltage supplied to itself. It is necessary to set a driving voltage suitable for each liquid crystal display device.

[0003]

Conventionally, when switching the voltage generated by the power supply circuit, a user or the like inputs an appropriate signal to the power supply circuit and sets a drive voltage suitable for each liquid crystal display device. However, in some cases, the technique of inputting a signal to the power supply circuit requires skill in execution, and the user or the like may input an erroneous signal to the power supply circuit when switching the voltage generated by the power supply circuit. Was.

The present invention has been made in view of the above circumstances, and has as its object to provide a voltage transformation control circuit that easily and reliably changes the voltage generated by a power supply circuit.

[0005]

In order to achieve the above object, a transformer control circuit according to a first aspect of the present invention comprises a plurality of ordered output terminals for outputting a plurality of different voltages, A plurality of voltage holding capacitors connected between the plurality of output terminals and a reference potential,
A charge-carrying capacitor for charging a charge supplied from a voltage source that generates a power supply voltage, and the charge-carrying capacitor charged with the charge is connected in series to the voltage-holding capacitor, and the charge-carrying capacitor is In order to charge the voltage at both ends of the series connection circuit of the voltage holding capacitor to the voltage holding capacitor connected to the output terminal immediately above the output terminal to which the voltage holding capacitor is connected, A control circuit for switching a voltage output by a power supply circuit, comprising: a control unit for switching connection between the charge transport capacitor and the voltage holding capacitor, wherein the voltage source is selected as one of the output terminals. The voltage holding capacitor connected between the output terminal to which the voltage source is connected and the reference potential. Charging the charge supplied from the voltage source, said charge transport capacitor, the is charged by the voltage source and connected lower than the output terminal voltage, and wherein the.

According to such a transformation control circuit, the voltage generated by the power supply circuit is changed by connecting the voltage source and the output terminal. For this reason, the voltage generated by the power supply circuit can be changed more easily and accurately than in the case where the voltage is changed by inputting a signal.

[0007] Specifically, the charge transporting capacitor is, for example, a series of the voltage holding capacitor connected to an output terminal lower than the output terminal connected to the voltage source and the charge transporting capacitor. The connection circuit charges the power supply voltage with the divided voltage.

[0008] The power supply circuit has a power supply voltage terminal for outputting a power supply voltage generated by the voltage source, and each of the output terminals of the power supply circuit has a shortest distance between the power supply voltage terminal and the power supply voltage terminal. A conductor connected at a distance may be arranged so as not to be short-circuited to any of the other output terminals. As a result, the power supply voltage terminal and the output terminal can be connected without contacting other output terminals, so that the voltage generated by the power supply circuit can be changed easily and without error. In addition, the risk of accidents such as erroneous contact of other output terminals after connecting the power supply voltage terminal and the output terminal is also prevented.

If the output terminal, the charge-carrying capacitor, and the control means are formed on a single integrated circuit, the power supply circuit may be provided with a voltage-holding capacitor external to the integrated circuit. It is easily configured.

Each end of the charge transporting capacitor is connected to the output terminal via, for example, an electrically intermittent current path, and in this case, the control means interrupts the current path. Any means may be provided as long as it has means for switching the connection between the charge transporting capacitor and the voltage holding capacitor.

When each end of the charge transfer capacitor is connected to the output terminal via a current path which can be electrically disconnected, specifically, for example, the lowest output terminal is set to a reference potential. One end of the charge-carrying capacitor is connected to each of the output terminals other than the lowest through the current paths separate from each other, and the other end of the charge-carrying capacitor is connected to a separate It is connected to each output terminal other than the highest through the current path. In this case, the control means includes a current path between the output terminal to which the voltage source is connected and the one end of the charge-carrying capacitor, and a lower-order output terminal closest to the output terminal and the charge-carrying capacitor. Charging the charge-carrying capacitor by closing the current path with the other end, then opening each currently closed current path, and connecting the output terminal to which the voltage source is connected and the other of the charge-carrying capacitor. By closing the current path with the end, and the current path between the upper output terminal closest to the output terminal and the one end of the charge transport capacitor,
The voltage at both ends of the series connection circuit of the charge transporting capacitor and the voltage holding capacitor is applied to the voltage holding capacitor connected to the upper output terminal nearest to the output terminal to which the voltage holding capacitor is connected. It may be charged.

If the control means includes means for sequentially switching the connection between the charge-carrying capacitor and the voltage-holding capacitor in response to a supplied timing signal, the control means can charge or charge the charge-carrying capacitor. Switching of the connection between the charge carrying capacitor and the voltage holding capacitor is performed under the control of a timing signal. Since the timing signal can be generated by causing a computer to execute a predetermined process, such a power supply circuit is suitable as a power supply circuit for driving a liquid crystal display element or the like under the control of the computer.

[0013] Further, in the transformer control method according to the second aspect of the present invention, a charge transport capacitor charged with a charge supplied from a voltage source for generating a power supply voltage is output to a plurality of different voltages. Are sequentially connected in series to a plurality of voltage holding capacitors respectively connected between a plurality of ordered output terminals and a reference potential, and both ends of a series connection circuit of the charge carrying capacitor and the voltage holding capacitor. A voltage between the charge transport capacitor and the voltage holding capacitor is charged so that a voltage is charged in the voltage holding capacitor connected to a higher-order output terminal closest to the output terminal to which the voltage holding capacitor is connected. A voltage control method for switching connections, wherein the voltage source is selectively connected to one of the output terminals, and an output terminal connected to the voltage source is connected to the base. Charging the voltage-holding capacitor connected between the power supply and the potential with the charge supplied from the voltage source, wherein the charge-carrying capacitor is charged at a lower voltage than an output terminal connected to the voltage source; It is characterized by the following.

According to such a transformation control method, the voltage generated by the power supply circuit is changed by connecting the voltage source and the output terminal. Therefore, the voltage to be generated can be changed easily and accurately as compared with the case where the change of the voltage to be generated is performed by inputting a signal.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a transformer control circuit according to an embodiment of the present invention will be described with reference to the drawings, taking a liquid crystal display device driven by a drive voltage having four values as an example. The liquid crystal display device according to the embodiment of the present invention includes a liquid crystal display element 10 and a drive circuit 20, as shown in FIG.

As schematically shown in FIG. 1, the liquid crystal display element 10 includes a plurality of signal electrodes (segment electrodes) 11 and a plurality of scanning electrodes (common lines) 13 arranged orthogonal to the signal electrodes 11. , A liquid crystal layer 15 disposed between the signal electrode 11 and the scanning electrode 13. Liquid crystal display element 1
In the case of 0, display is performed in accordance with a voltage applied between both the signal electrode 11 and the scanning electrode 13, using the intersection of the signal electrode 11 and the scanning electrode 13 as a pixel.

The drive circuit 20 is a circuit for controlling and driving the liquid crystal display element 10. The drive circuit 20 is shown in FIG.
As schematically shown in FIG. 1, a power supply circuit 21, a signal drive circuit 23, a scan drive circuit 25, a timing circuit 27,
It is composed of

The power supply circuit 21 boosts a power supply voltage VDD supplied to itself from the outside, and supplies drive voltages V1 and V
2, V3 and V4, and output these generated voltages. As shown in FIG. 2, the power supply circuit 21 includes a switch control circuit 211, switches SW1 to SW8, a charge-carrying capacitor CC, and voltage-holding capacitors C1 to C2.
4, a voltage follower circuit 213, and a charging capacitor C0.

Switch control circuit 211, switch SW1
To SW8, the charge transfer capacitor CC and the voltage follower circuit 213 are LSI (Large Scale Integrated).
circuit). This LSI includes output terminals T0 to T4 and TSS, supplies a voltage VRE described later from an output terminal T0, supplies a drive voltage V1 from an output terminal T1, supplies a drive voltage V2 from an output terminal T2, and supplies an output terminal The driving voltage V3 is supplied from T3, and the driving voltage V4 is supplied from the output terminal T4. The output terminals T0 to T4 and TSS are output terminals T0, TSS, T1, T2, T3 and TSS.
4 are arranged in a straight line.

The switch control circuit 211 controls the opening and closing of the current paths of the switches SW1 to SW8 in a predetermined order as described later in accordance with the clock signal CK supplied to itself.

The switches SW1 to SW8 open and close their own current paths under the control of the switch control circuit 211.
One end of each of the current paths of the switches SW1, SW3, SW5, and SW7 is connected to one end of the charge transport capacitor CC. The other end of the charge transport capacitor CC is connected to one end of each of the current paths of the switches SW2, SW4, SW6 and SW8.

The other end of the current path of the switch SW1 forms an output terminal TSS. The other ends of the current paths of the switches SW2 and SW3 are connected to each other, and the output terminal T of the LSI
1 are formed. The other ends of the current paths of the switches SW4 and SW5 are connected to each other to form an output terminal T2 of the LSI. The other ends of the current paths of the switches SW6 and SW7 are connected to each other to form an output terminal T3 of the LSI. The other end of the current path of the switch SW8 forms an output terminal T4 of the LSI.

One end of each of the voltage holding capacitors C1 to C4 is grounded. The other end of the voltage holding capacitor C1 is connected to the output terminal T1 of the LSI. The other end of the voltage holding capacitor C2 is connected to the output terminal T2 of the LSI. The other end of the voltage holding capacitor C3 is an LSI
Is connected to the output terminal T3. The other end of the voltage holding capacitor C4 is connected to the output terminal T4 of the LSI. The output terminal TSS of the LSI is grounded.

The voltage follower circuit 213 has an input terminal and an output terminal, and outputs a voltage VRE substantially equal to the power supply voltage VDD supplied from the outside to its own input terminal from its own output terminal. One end of the charging capacitor C0 is grounded, and the other end is connected to the output terminal of the voltage follower circuit 213. Therefore, the charging capacitor C0 is charged with the output voltage VRE of the voltage follower circuit 213.

When the output terminal T0 of its own LSI is connected to the output terminal T1 as shown in FIG. 3, for example, the power supply circuit 21 of FIG.
Generates double, triple, and quadruple voltages to generate its own LS
Output from the I output terminals T1, T2, T3 and T4.

As shown in FIG. 4, when the output terminal T0 of its own LSI is connected to the output terminal T2, the power supply circuit 21 of FIG.
Voltages of 2, 1, 3/2 and 2 times are generated and output from output terminals T1, T2, T3 and T4 of the own LSI.

The signal drive circuit 23 is driven by the drive signals V1 to V4 supplied from the output terminals T1 to T4 of the LSI of the power supply circuit 21 according to the image signal supplied to itself from the outside. A voltage is selected and applied to each signal electrode 11.

The scan drive circuit 25 includes a timing circuit 27
, And selects one of the drive voltages V1 to V4 supplied from the power supply circuit 21 to generate a selection signal and a non-selection signal having a predetermined waveform. Then, a selection signal is applied to the scanning electrodes 13 in the selected state, and a non-selection signal is applied to the scanning electrodes 13 in the non-selected state.

The timing circuit 27 controls the operation timing of the drive circuit 20 so that each part of the drive circuit 20 performs the operation described later. Specifically, for example, in order that the switches SW1 to SW8 of the power supply circuit 21 in FIG. 2 are controlled to open and close according to an operation described later, the above-described clock signal CK is transmitted to the switch control circuit 211 of the power supply circuit 21.
To supply.

Next, the operation of the liquid crystal display device will be described. First, when the liquid crystal display element 10 is driven by a voltage having a magnitude of 1, 2, 3, or 4 times the magnitude of the power supply voltage VDD supplied to the power supply circuit 21, The operation of the display device will be described.

In this case, as shown in FIG. 3, the user or the like changes the output terminal T0 of the LSI of the power supply circuit 21 to the output terminal T.
Connect to 1. When the power supply voltage VDD is supplied to the drive circuit 20 with the output terminals T0 and T1 connected to each other, the voltage follower circuit 21 of the power supply circuit 21 of FIG.
Reference numeral 3 amplifies the supplied voltage VDD by a factor of 1, and outputs a voltage VRE based on the potential of the grounded output terminal TSS (reference potential VSS). As a result, the voltage VRE is applied between both ends of the charging capacitor C0 and the voltage holding capacitor C1, and the capacitors C0 and C1 are charged. As a result, the voltage between both ends of the capacitors C0 and C1 becomes almost the voltage VRE.

The switch control circuit 211 first turns on the switches SW1 and SW2 according to the clock signal supplied from the timing circuit 27, as shown in FIG.
Then, the charge-carrying capacitor CC is connected in parallel to the capacitors C0 and C1. Then, the charge transport capacitor CC is charged, and the voltage between both ends of the charge transport capacitor CC becomes substantially VRE. As a result, the voltage of the output terminal T1 with respect to the reference potential VSS becomes substantially VRE.

Next, as shown in FIG. 5, the switch control circuit 211 turns off the switches SW1 and SW2 and turns on the switches SW3 and SW4. Thus, the voltage holding capacitor C2 is connected in parallel to the series circuit including the charge carrying capacitor CC and the voltage holding capacitor C1.

Accordingly, the voltage holding capacitor C2 is charged by a series circuit including the charge carrying capacitor CC and the voltage holding capacitor C1. Voltage between both ends of charge transport capacitor CC and voltage holding capacitor C
1 is VRE, the voltage between both ends of the series circuit (that is, the voltage between both ends of the voltage holding capacitor C2) is approximately (2 · VRE). As a result, the voltage of the output terminal T2 with respect to the reference potential VSS becomes substantially (2 · VRE).

Next, as shown in FIG. 5, the switch control circuit 211 turns off the switches SW3 and SW4 and turns on the switches SW5 and SW6. As a result, the voltage holding capacitor C3 is connected in parallel to the series circuit of the charge carrying capacitor CC and the voltage holding capacitor C2.

Accordingly, the voltage holding capacitor C3 is charged by a series circuit including the charge carrying capacitor CC and the voltage holding capacitor C2. Since the voltage across the charge-carrying capacitor CC is VRE and the voltage across the voltage-holding capacitor C2 is (2 · VRE), the voltage across both series circuits (ie,
The voltage across the voltage holding capacitor C3) is approximately (3 · VRE). As a result, the voltage of the output terminal T3 with respect to the reference potential VSS becomes substantially (3.VRE).

Next, as shown in FIG. 5, the switch control circuit 211 turns off the switches SW5 and SW6 and turns on the switches SW7 and SW8. Thereby, the voltage holding capacitor C4 is connected in parallel to the series circuit of the charge carrying capacitor CC and the voltage holding capacitor C3.

Therefore, the voltage holding capacitor C4 is charged by a series circuit including the charge carrying capacitor CC and the voltage holding capacitor C3. Since the voltage across the charge-carrying capacitor CC is VRE and the voltage across the voltage-holding capacitor C3 is (3 · VRE),
The voltage between both ends of these series circuits (that is, the voltage between both ends of the voltage holding capacitor C4) is approximately (4 ·
VRE). As a result, the voltage of the output terminal T4 with respect to the reference potential VSS becomes substantially (4.VRE).

By performing the above-described operations, the charging capacitor C0, the charge-carrying capacitor CC, and the voltage-holding capacitor C1 are charged, and then the charge accumulated in the charge-carrying capacitor CC and the voltage-holding capacitor C1 is reduced. The voltage is distributed to the voltage holding capacitor C2. Further, the charges accumulated in the charge carrying capacitor CC and the voltage holding capacitor C2 are further transferred to the voltage holding capacitor C3.
Then, the charges accumulated in the charge transport capacitor CC and the voltage holding capacitor C3 are distributed to the voltage holding capacitor C4.

Thus, the voltage holding capacitors C1 to C1
Charge is accumulated in C4, and the voltage VRE is increased about
Voltages V1, V2, V corresponding to those boosted by a factor of four and four
3 and V4 are output terminals T1 of the LSI of the power supply circuit 21,
Occurs at T2, T3 and T4.

The signal drive circuit 23 is connected to the LS
Drive voltages V1 to V4 are supplied from output terminals T1 to T4 of I, and image signals are supplied from outside. Then, the driving voltages V1 to V4 in accordance with the image signals supplied thereto.
Is selected, and the selected drive voltage is applied to each signal electrode 11.
Is applied.

The scan drive circuit 25 selects one of the drive voltages V1 to V4 in response to the timing signal supplied from the timing circuit 27. Then, a selection signal is generated and applied to the selected scanning electrode 13, and a non-selection signal is generated and applied to the non-selected scanning electrode 13.

As described above, when the output terminals T0 and T1 of the LSI of the power supply circuit 21 are connected to each other, the drive circuit 20 boosts the voltage VRE by one, two, three and four times. It operates as a 4-fold booster circuit. The user or the like can easily and accurately change the drive voltage generated by the power supply circuit 21 by connecting the output terminal T0 and the output terminal T1 with an external circuit.

Next, the liquid crystal display element 10 is
Of the power supply voltage VDD supplied to the
The operation of the liquid crystal display device in the case where the liquid crystal display device is driven by a voltage of 3/2 times and twice as large will be described.

In this case, the user or the like changes the output terminal T0 of the LSI of the power supply circuit 21 to the output terminal T as shown in FIG.
Connect to 2. When the power supply voltage VDD is supplied to the drive circuit 20 in a state where the output terminals T0 and T2 are connected to each other, the voltage follower circuit 213 of the power supply circuit 21
As in the case of the above-described operation of the 1- to 4-fold boosting circuit, the supplied voltage VDD is amplified by one and the voltage VRE is output.

As a result, the voltage VRE is changed to the charging capacitor C
0, and is applied across both ends of the voltage holding capacitor C2. As a result, the voltage between both ends of the capacitors C0 and C2 becomes substantially the voltage VRE. Therefore, the voltage of the output terminal T2 with respect to the reference potential VSS becomes substantially VRE.

The switch control circuit 211 first turns on the switches SW3 and SW4 according to the clock signal supplied from the timing circuit 27. Then, the voltage holding capacitor C2 is connected in parallel to the series circuit including the charge carrying capacitor CC and the voltage holding capacitor C1.

Thus, the charge transport capacitor CC and the voltage holding capacitor C1 are connected to the charge capacitor C0.
And the charge supplied from the voltage holding capacitor C2 is
Substantially equal amounts are accumulated in each other.

As a result, the voltage between both ends of the charge-carrying capacitor CC and the voltage between both ends of the voltage-holding capacitor C1, for example, the charge-carrying capacitor CC and the capacitance of the voltage-holding capacitor C1 are substantially equal. , They are almost equal to {(1/2) · VRE}. As a result, the voltage of the output terminal T1 with respect to the reference potential VSS becomes substantially {(1/2) .VRE}.

Next, the switch control circuit 211 turns off the switches SW3 and SW4 and turns on the switches SW5 and SW6. As a result, the voltage holding capacitor C3 is connected in parallel to the series circuit of the charge carrying capacitor CC and the voltage holding capacitor C2.

Therefore, the voltage holding capacitor C3 is charged by a series circuit including the charge carrying capacitor CC and the voltage holding capacitor C2. The voltage between both ends of the charge carrying capacitor CC is {(1/2) · VRE}, and the voltage between both ends of the voltage holding capacitor C2 is VRE. The voltage across the voltage holding capacitor C3 is approximately ｛(3
/ 2) · VRE｝. As a result, the voltage of the output terminal T3 with respect to the reference potential VSS becomes substantially {(3/2) .VRE}.

Next, the switch control circuit 211 turns off the switches SW5 and SW6 and turns on the switches SW7 and SW8. Thereby, the voltage holding capacitor C4 is connected in parallel to the series circuit of the charge carrying capacitor CC and the voltage holding capacitor C3.

Therefore, the voltage holding capacitor C4 is charged by a series circuit including the charge carrying capacitor CC and the voltage holding capacitor C3. The voltage between both ends of the charge transfer capacitor CC is {(1/2) · VRE}, and the voltage between both ends of the voltage holding capacitor C2 is {(3
/ 2) · VRE 間 の, the voltage across the voltage holding capacitor C3 connected in parallel to the series circuit of these two is approximately (2 · VRE). As a result, the reference potential V
The voltage of the output terminal T4 with respect to SS is substantially (2 · VRE).

Next, the switch control circuit 211 turns off the switches SW7 and SW8 and turns on the switches SW1 and SW2. As a result, the charge transport capacitor CC
The voltage holding capacitor C1 is connected in parallel.

Therefore, the voltage holding capacitor C1 is charged by the charge carrying capacitor CC. The voltage between both ends of the charge transfer capacitor CC is {(1/2) · VRE}
Therefore, the voltage between both ends of the voltage holding capacitor C1 connected in parallel to the charge carrying capacitor CC is substantially {(1/2) · VRE}. As a result, the reference potential VSS
Is approximately ｛(1/2) · VR
E｝.

By performing the above-described operations, the charging capacitor C0 and the voltage holding capacitor C2 are charged, and then the charge accumulated in the charging capacitor C0 and the voltage holding capacitor C2 is transferred to the charge carrying capacitor CC.
And the voltage holding capacitor C1. Further, the charges accumulated in the charge carrying capacitor CC and the voltage holding capacitor C2 are distributed to the voltage holding capacitor C3, and then the charges accumulated in the charge carrying capacitor CC and the voltage holding capacitor C3 are held in voltage. To the storage capacitor C4.

Thus, the voltage holding capacitors C1 to C1
The electric charge is accumulated in C4, and the voltage VRE is increased by about 1/2 times, 1 time,
Voltages V1 and V corresponding to a voltage that has been boosted 3/2 times and 2 times
2, V3 and V4 are generated at the output terminals T1, T2, T3 and T4 of the LSI of the power supply circuit 21.

The operations of the signal drive circuit 23, the scan drive circuit 25, and the timing circuit 27 are substantially the same as the operations of the above-described 1- to 4-fold booster circuit.

In this way, when the output terminals T0 and T2 of the LSI of the power supply circuit 21 are connected to each other, the drive circuit 20 increases the voltage VRE by a factor of 1/2, 1, 3/2 and 2 times. And operates as a 1/2 to 2 times boosting circuit. The user or the like can easily and accurately change the drive voltage generated by the power supply circuit 21 by connecting the output terminal T0 and the output terminal T2 in an external circuit.

As described above, according to the transformation control circuit of the present invention, the terminal T0 of the LSI of the power supply circuit 21 is connected to the terminals T1 to T1.
By being connected to any one of T4, the drive voltage obtained by boosting the supplied voltage is changed. Therefore, as compared with a conventional power supply circuit in which the drive voltage is changed by input of a signal by a user or the like, it is possible to prevent a problem caused by a mistake in input of a signal of a user or the like. Further, since the drive voltage can be changed only by changing the connection between the output terminals arranged outside the LSI, the drive voltage can be easily and reliably changed.

The configuration of the liquid crystal display device is not limited to the above. For example, in the above description, four voltage holding capacitors C1 to C4 are provided so that the drive voltages V1 to V4
Was generated, but a voltage holding capacitor was further provided,
Five or more drive voltages may be generated. In this way, more drive voltages can be generated.
Further, the LSI may include a plurality of charge transport capacitors CC, and a plurality of combinations of drive voltages may be generated. Further, the power supply circuit 21 of the liquid crystal display device is not limited to a drive voltage for driving the liquid crystal display element 10 and may generate a combination of a plurality of voltages used for any purpose.

Each output terminal is connected to the output terminals T0 and Ts.
When the terminals are arranged in a straight line in the order of S, T1, T2, T3 and T4, when the user or the like connects the output terminal T0 of the LSI of the power supply circuit 21 to the output terminals T1 to T4, the wiring between the terminals crosses. Therefore, it is difficult to connect the terminals. However, if the output terminals of the LSI are arranged such that the output terminal T0 is sandwiched between the output terminals T1 to T4 to be connected to the output terminal T0, the user or the like can use L
It is possible to easily and reliably connect the output terminal T0 to the output terminals T1 to T4 outside the SI.

For example, when the power supply circuit 21 is used as a 1- to 4-fold boosting circuit or a 1/2 to 2-fold boosting circuit,
As shown in FIG. 6, the output terminal T0 is arranged between the output terminal T1 and the output terminal T2. When the user uses the output terminal T0 as an output terminal T1,
Are connected as shown by a broken line L1. On the other hand, when used as a 1/2 to 2 times booster circuit, the output terminal T0 is connected to the output terminal T2.
Is connected as shown by a broken line L2.

In the case where the output terminals T0 to T4 are arranged in this manner, since the wiring does not intersect between the terminals shown in FIG. 3 and FIG. 4, the user and the like need not connect the output terminal T0 to the output terminal T1, The connection between the output terminal T0 and the output terminal T2 can be more easily and reliably performed.

When the output terminal T0 is arranged between the output terminals T1 to T4 as shown in FIG. 6, the signal electrode 11 and the scanning electrode 13 of the liquid crystal display element 10 of FIG. 1 are formed. Direct output terminal T0 with transparent conductive film (ITO)
And the output terminals T1 to T4. According to this configuration, the user or the like needs to output the output terminal T0 and the output terminals T1 to T1.
4 can be more easily and reliably connected. Further, after connecting the output terminal T0 and the output terminals T1 to T4, the danger of an accident such as an erroneous contact of output terminals other than those connected to each other is also prevented.

The output terminal T0 and the output terminals T1 to T4 on the LSI of the power supply circuit 21 are connected to the output terminal T0 to one of the output terminals T1 to T4 at a substantially shortest distance from the output terminal. It may be arranged such that it does not come into contact with one of T1 to T4 that is not connected to the output terminal T0. Specifically, for example, the output terminals T0 to T4
May be arranged in a staggered manner as shown in FIG.

When the output terminals T0 to T4 are arranged as shown in FIG. 7, any one of the output terminals T1 to T4 can be touched with a transparent conductive film (ITO) without touching the other three. It can be connected to the output terminal T0 with a substantially shortest distance. Therefore, it is possible to easily switch the four types of combinations of the drive voltages generated by the power supply circuit 21.

Also, when the combination of the driving voltages is set to four or more, the output terminals are arranged in a zigzag like the arrangement shown in FIG.
If the conductor that connects the terminal and any other output terminal at a substantially shortest distance is arranged so as not to contact an output terminal that is not connected to the output terminal T0, it is easy to switch the combination of drive voltages. Can be done. Further, after the output terminal T0 is connected to another output terminal, the danger of an accident such as erroneous contact of output terminals other than those connected to each other is also prevented.

[0069]

As described above, the transformer control circuit of the present invention changes the voltage generated by the power supply circuit by short-circuiting the output terminal of the power supply circuit and the reference voltage. For this reason, the voltage generated by the power supply circuit can be changed more easily and accurately than in the case where the voltage is changed by inputting a signal.

[Brief description of the drawings]

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

FIG. 2 is a diagram schematically illustrating a configuration of a power supply circuit of FIG. 1;

FIG. 3 is an example of wiring between terminals of the power supply circuit of FIG. 1;

FIG. 4 is an example of wiring between terminals of the power supply circuit of FIG. 1;

FIG. 5 is a timing chart showing an operation of the liquid crystal display device of FIG.

FIG. 6 is a modification of the power supply circuit of FIG. 1;

FIG. 7 is a modification example of the LSI of the power supply circuit of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Liquid crystal display element, 11 ... Signal electrode, 13 ... Scan electrode, 15 ... Liquid crystal layer, 20 ... Drive circuit, 21 ... Power supply circuit, 23 ... Signal drive circuit , 25 ... scan drive circuit, 2
7 ... timing circuit, 211 ... switch control circuit, 2
13: Voltage follower circuit, CC: Charge transport capacitor, C0: Charge capacitor, C1 to C4: Voltage holding capacitor

Claims (8)

[Claims] A plurality of output terminals for outputting a plurality of mutually different voltages, a plurality of voltage holding capacitors respectively connected between the plurality of output terminals and a reference potential, and a power supply voltage. A charge-carrying capacitor for charging a charge supplied from a voltage source that generates the charge, and the charge-carrying capacitor charged with the charge are connected in series to the voltage-holding capacitor, and the charge-carrying capacitor and the voltage The charge transfer device is configured to charge the voltage at both ends of the series connection circuit of the holding capacitor to the voltage holding capacitor connected to the output terminal immediately above the output terminal to which the voltage holding capacitor is connected. And a control means for switching the connection between the capacitor for voltage control and the voltage holding capacitor. A circuit for selectively connecting the voltage source to one of the output terminals, wherein the voltage holding capacitor is connected between an output terminal to which the voltage source is connected and the reference potential. Wherein the charge-carrying capacitor is charged at a lower voltage than an output terminal connected to the voltage source. 2. The charge transfer capacitor according to claim 1, wherein the power supply voltage is controlled by a series connection circuit including the voltage holding capacitor connected to an output terminal lower than the output terminal connected to the voltage source and the charge transfer capacitor. The voltage transformation control circuit according to claim 1, wherein is charged with a divided voltage. 3. The power supply circuit includes a power supply voltage terminal for outputting a power supply voltage generated by the voltage source, and each of the output terminals of the power supply circuit substantially connects the power supply voltage terminal to the power supply voltage terminal. 3. The transformer control circuit according to claim 1, wherein a conductor connected to the output terminal at the shortest distance is arranged so as not to be short-circuited to any of the other output terminals. 4. The transformer control circuit according to claim 1, wherein the output terminal, the charge-carrying capacitor and the control means are formed in a single integrated circuit. 5. Each end of the charge transfer capacitor is connected to the output terminal via an electrically interruptable current path, and the control means interrupts the current path to disconnect the charge. The transformer control circuit according to any one of claims 1 to 4, further comprising: means for switching a connection between the transport capacitor and the voltage holding capacitor. 6. The lowermost output terminal is connected to a reference potential, and one end of the charge-carrying capacitor is connected to each of the output terminals other than the lowest through the current paths separate from each other. The other end of the charge-carrying capacitor is connected to each of the output terminals other than the highest through the current paths separate from each other, and the control means includes an output terminal connected to the voltage source and the output terminal connected to the voltage source. Charging the charge-carrying capacitor by closing a current path with the one end of the charge-carrying capacitor, and a current path between a lower output terminal immediately adjacent to the output terminal and the other end of the charge-carrying capacitor; Next, while opening each current path that is currently closed, a current path between the output terminal to which the voltage source is connected and the other end of the charge transport capacitor,
By closing the current path between the higher-order output terminal closest to the output terminal and the one end of the charge-carrying capacitor, the voltage across the series connection circuit of the charge-carrying capacitor and the voltage-holding capacitor is The voltage transformation control circuit according to claim 5, wherein the voltage holding capacitor connected to an upper output terminal closest to the output terminal to which the voltage holding capacitor is connected is charged. 7. The control device according to claim 1, wherein said control means includes means for sequentially switching connection between said charge transport capacitor and said voltage holding capacitor in response to a supplied timing signal. 7. The transformation control circuit according to any one of claims 6 to 6. 8. A charge transporting capacitor charged with a charge supplied from a voltage source for generating a power supply voltage is connected between a plurality of ordered output terminals for outputting a plurality of different voltages and a reference potential. Connected in series to a plurality of voltage holding capacitors respectively connected to the capacitor, and outputs the voltage between both ends of a series connection circuit of the charge carrying capacitor and the voltage holding capacitor to an output to which the voltage holding capacitor is connected. A voltage-change control method for switching connection between the charge-carrying capacitor and the voltage-holding capacitor so as to charge the voltage-holding capacitor connected to a higher-order output terminal closest to the terminal, comprising: The voltage holding capacitor selectively connected to one of the output terminals and connected between the output terminal connected to the voltage source and the reference potential; And charging the electric charge supplied from the voltage source, and charging the charge carrying capacitor at a voltage lower than an output terminal connected to the voltage source.