Be applied to prevent in the liquid crystal indicator detection holding circuit of liquid crystal polarization
Technical field
The present invention relates to a kind of detection holding circuit, refer to a kind of detection holding circuit that is applied to prevent in the liquid crystal indicator liquid crystal polarization especially.
Background technology
With reference to Fig. 1, it is the electrical block diagram of available liquid crystal display device.As shown in Figure 1, this liquid crystal indicator 100 comprises low pressure drop (LDO, Low Drop-out) voltage regulator 110, DC-DC converter 120, time schedule controller (Timing controller) 130, charge pump circuit 140, scan drive circuit 150, data drive circuit 160 and display panels 170.The input voltage V that this low drop out voltage regurator 110 receives from external circuit
CcCarry out voltage-regulation, and then provide operating voltage V to this time schedule controller 130
DdThe input voltage V that this DC-DC converter 120 receives from external circuit
CcCarry out DC voltage and be converted to output voltage V
Aa, this output voltage V
AaProvide to this charge pump circuit 140 and this data drive circuit 160.This charge pump circuit 140 is with this output voltage V
AaBe converted into the required grid operating voltage V of this scan drive circuit 150
GH, V
GLThis time schedule controller 130 is set according to sequential this image data signal is transferred to this data drive circuit 160, sends scan control signal simultaneously to this scan drive circuit 150.
But, the voltage V that this low drop out voltage regurator 110 and this DC-DC converter 120 are supplied
Aa, V
DdUnder the abnormal conditions or this time schedule controller 130 normally provides under the power supply situation at this low drop out voltage regurator 110 and this DC-DC converter 120, export abnormal scan control signal or data controlling signal and give this scan drive circuit 150 or this data drive circuit 160, thereby cause liquid crystal under long-time stress (stress), to cause the phenomenon of liquid crystal polarization.
Generally speaking, may cause the factor of liquid crystal polarization generally to be divided into three kinds because abnormal power supply supply or time schedule controller are exported abnormal control signal:
(1) under the time schedule controller output normal control signal situation, and DC-DC converter stop supplies power supply (shut down);
(2) time schedule controller is exported under abnormal control signal situation, and DC-DC converter continues power supply; And
(3) low drop out voltage regurator output voltage shakiness, and then cause time schedule controller to export abnormal control signal.
Therefore, the present invention is the improvement invention in view of the defective of prior art, invents out " being applied to prevent in the liquid crystal indicator detection holding circuit of liquid crystal polarization " of the application.
Summary of the invention
Fundamental purpose of the present invention is for providing a kind of detection holding circuit that is applied to prevent in the liquid crystal indicator liquid crystal polarization; under the undesired supply voltage condition of the low drop out voltage regurator of liquid crystal indicator; this testing circuit can be closed the input voltage that offers this liquid crystal indicator from external circuit, avoids liquid crystal causing liquid crystal to cause the phenomenon of liquid crystal polarization under the undesired signal under long-time stress.
Another object of the present invention is for providing a kind of detection holding circuit that is applied to prevent in the liquid crystal indicator liquid crystal polarization; under the undesired supply voltage condition of DC-DC converter; this testing circuit can be closed the input voltage that offers this liquid crystal indicator from external circuit, avoids liquid crystal causing liquid crystal to cause the phenomenon of liquid crystal polarization under the undesired signal under long-time stress.
Another object of the present invention is for providing a kind of detection holding circuit that is applied to prevent in the liquid crystal indicator liquid crystal polarization; when time schedule controller normally provides under the power supply situation at this low drop out voltage regurator and this DC-DC converter; export abnormal scan control signal or data controlling signal and give scan drive circuit or data drive circuit; this testing circuit can be closed the input voltage that offers this liquid crystal indicator from external circuit, avoids liquid crystal causing liquid crystal to cause the phenomenon of liquid crystal polarization under the undesired signal under long-time stress.
For reaching above-mentioned purpose, according to an aspect of the present invention, provide a kind of liquid crystal indicator, comprise:
Display panels;
Scan drive circuit;
Data drive circuit;
Time schedule controller, be electrically connected described data drive circuit and described scan drive circuit, according to the sequential setting image data signal is transferred to described data drive circuit, send scan control signal simultaneously to described scan drive circuit, so that described scan drive circuit and described data drive circuit drive described display panels;
Switch, the input voltage of electrical connection external circuit;
DC-DC converter, reception is carried out DC voltage from the described input voltage of described external circuit and is converted to output voltage, so that described data drive circuit and the required operating voltage of described scan drive circuit to be provided, wherein said switch is electrically connected described DC-DC converter and low drop out voltage regurator; And
Testing circuit, be electrically connected the output terminal of described DC-DC converter, be used to detect described output voltage, when described output voltage exceeds described output voltage normal operating voltage scope, producing control signal ends to control described switch, interrupt all power supply supplies of described display panels, avoid liquid crystal under undesired signal, to cause the phenomenon of liquid crystal polarization.
According to a further aspect in the invention, provide a kind of liquid crystal indicator, comprised:
Display panels;
Scan drive circuit;
Data drive circuit;
Time schedule controller, be electrically connected described data drive circuit and described scan drive circuit, according to the sequential setting image data signal is transferred to described data drive circuit, send scan control signal simultaneously to described scan drive circuit, so that described scan drive circuit and described data drive circuit drive described display panels;
Switch, the input voltage of electrical connection external circuit;
DC-DC converter, reception is carried out DC voltage from the described input voltage of described external circuit and is converted to output voltage, so that described data drive circuit and the required operating voltage of described scan drive circuit to be provided, wherein said switch is electrically connected described DC-DC converter and low drop out voltage regurator; And
Testing circuit, be electrically connected the output terminal of described time schedule controller, be used to detect the output signal of described time schedule controller, when described testing circuit detects described time schedule controller and exports abnormal described output signal, producing control signal ends to control described switch, interrupt all power supply supplies of described display panels, avoid liquid crystal under undesired signal, to cause the phenomenon of liquid crystal polarization.
According to a further aspect in the invention, provide a kind of liquid crystal indicator, comprised:
Display panels;
Scan drive circuit;
Data drive circuit;
Time schedule controller, be electrically connected described data drive circuit and described scan drive circuit, according to the sequential setting image data signal is transferred to described data drive circuit, send scan control signal simultaneously to described scan drive circuit, so that described scan drive circuit and described data drive circuit drive described display panels;
Switch, the input voltage of electrical connection external circuit;
Low drop out voltage regurator, the described input voltage that receives from described external circuit carries out voltage-regulation, and to provide described time schedule controller required operating voltage, wherein said switch is electrically connected DC-DC converter and described low drop out voltage regurator; And
Testing circuit, be electrically connected the output terminal of described low drop out voltage regurator, be used to detect the output voltage of described low drop out voltage regurator, when described output voltage exceeds described output voltage normal operating voltage scope, producing control signal ends to control described switch, interrupt all power supply supplies of described display panels, avoid liquid crystal under undesired signal, to cause the phenomenon of liquid crystal polarization.
According to a further aspect in the invention, provide a kind of detection holding circuit that is applied to liquid crystal indicator, described liquid crystal indicator comprises display panels; Scan drive circuit; Data drive circuit; Time schedule controller, be electrically connected described data drive circuit and described scan drive circuit, according to the sequential setting image data signal is transferred to described data drive circuit, send scan control signal simultaneously to described scan drive circuit, so that described scan drive circuit and described data drive circuit drive described display panels; And DC-DC converter, receive input voltage from external circuit and carry out DC voltage and be converted to output voltage, so that described data drive circuit and the required operating voltage of described scan drive circuit to be provided; Described detection holding circuit comprises:
Switch is electrically connected the described input voltage of described external circuit, and wherein said switch is electrically connected described DC-DC converter and low drop out voltage regurator; And
Testing circuit, be electrically connected the output terminal of described DC-DC converter, be used to detect described output voltage, when described output voltage exceeds described output voltage normal operating voltage scope, producing control signal ends to control described switch, interrupt all power supply supplies of described display panels, avoid liquid crystal under undesired signal, to cause the phenomenon of liquid crystal polarization.
According to a further aspect in the invention, provide a kind of detection holding circuit that is applied to liquid crystal indicator, described liquid crystal indicator comprises display panels; Scan drive circuit; Data drive circuit; Time schedule controller, be electrically connected described data drive circuit and described scan drive circuit, according to the sequential setting image data signal is transferred to described data drive circuit, send scan control signal simultaneously to described scan drive circuit, so that described scan drive circuit and described data drive circuit drive described display panels; And DC-DC converter, receive input voltage from external circuit and carry out DC voltage and be converted to output voltage, so that described data drive circuit and the required operating voltage of described scan drive circuit to be provided; Described detection holding circuit comprises:
Switch is electrically connected on the described input voltage of described external circuit, and wherein said switch is electrically connected described DC-DC converter and low drop out voltage regurator; And
Testing circuit, be electrically connected the output terminal of described time schedule controller, be used to detect the output signal of described time schedule controller, when described testing circuit detects described time schedule controller and exports abnormal described output signal, producing control signal ends to control described switch, interrupt all power supply supplies of described display panels, avoid liquid crystal under undesired signal, to cause the phenomenon of liquid crystal polarization.
According to a further aspect in the invention, provide a kind of detection holding circuit that is applied to liquid crystal indicator, described liquid crystal indicator comprises display panels; Scan drive circuit; Data drive circuit; Time schedule controller, be electrically connected described data drive circuit and described scan drive circuit, according to the sequential setting image data signal is transferred to described data drive circuit, send scan control signal simultaneously to described scan drive circuit, so that described scan drive circuit and described data drive circuit drive described display panels; And low drop out voltage regurator, the input voltage that receives from external circuit carries out voltage-regulation, to provide described time schedule controller required operating voltage; Described detection holding circuit comprises:
Switch is electrically connected on the described input voltage of described external circuit, and wherein said switch is electrically connected DC-DC converter and described low drop out voltage regurator; And
Testing circuit, be electrically connected the output terminal of described low drop out voltage regurator, be used to detect the output voltage of described low drop out voltage regurator, when described output voltage exceeds described output voltage normal operating voltage scope, producing control signal ends to control described switch, interrupt all power supply supplies of described display panels, avoid liquid crystal under undesired signal, to cause the phenomenon of liquid crystal polarization.
By the following drawings and detailed description, can more understand the present invention in depth.
Description of drawings
Fig. 1 is the electrical block diagram of available liquid crystal display device;
Fig. 2 A, 2B are the detection holding circuit synoptic diagram that is applied to prevent in the liquid crystal indicator liquid crystal polarization of the application's first preferred embodiment;
Fig. 3 is the DC-DC converter output voltage detection holding circuit synoptic diagram that is applied to prevent in the liquid crystal indicator liquid crystal polarization of the application's second preferred embodiment;
Fig. 4 is the time schedule controller output signal detection holding circuit synoptic diagram that is applied to prevent in the liquid crystal indicator liquid crystal polarization of the application's the 3rd preferred embodiment;
Fig. 5 is the low drop out voltage regurator output voltage detection holding circuit synoptic diagram that is applied to prevent in the liquid crystal indicator liquid crystal polarization of the application's the 4th preferred embodiment;
Fig. 6 is the detection holding circuit synoptic diagram that is applied to prevent in the liquid crystal indicator liquid crystal polarization of the application's the 5th preferred embodiment.
Embodiment
Display packing and display for describing display of the present invention illustrate it with following specific embodiment, but interest field of the present invention is not limited to following embodiment.
Shown in Fig. 2 A, 2B, it is the detection holding circuit synoptic diagram that is applied to prevent in the liquid crystal indicator liquid crystal polarization of the application's first preferred embodiment.Shown in Fig. 2 A, 2B, switch 220 is electrically connected the input voltage V of external circuit via fuse (fuse) 210
CcThis DC-DC converter 230 is electrically connected this switch 220, receives the input voltage V from external circuit
Cc, be converted to output voltage V to carry out DC voltage
Aa, this output voltage V
AaProvide to back level dc conversion modules (for example: charge pump circuit 270) and data drive circuit 290.This back level dc conversion modules is with this output voltage V
AaBe converted into the required grid operating voltage of scan drive circuit 280.The input voltage V that low drop out voltage regurator 240 receives from external circuit
CcCarry out voltage-regulation, and then provide operating voltage V to the time schedule controller 260 of this liquid crystal indicator
Dd
Testing circuit 250 is by 251,252 formations of two reverse logic doors (NOT Gate).Wherein these reverse logic door 251 1 ends are used for receiving the input voltage V from external circuit
Cc, the other end is used for detecting any voltage that may be unusual.Its truth table is as follows:
V
cc |
V
det |
V
CONTROL |
Remarks |
0 |
0 |
1 |
V
ccNormal input
|
0 |
1 |
1 |
This situation does not exist |
1 |
0 |
0 |
Close V
ccInput
|
1 |
1 |
1 |
V
ccNormal input
|
As this input voltage V
CcWhen not importing as yet, input voltage V
CcBe 0, detect voltage V
DetAlso be 0, so control signal V
ControlOutput valve is 1, and this moment, this testing circuit 250 was controlled these switch 220 normallies, so this input voltage V
CcNormally provide voltage to this DC-DC converter 230 and this low drop out voltage regurator 240.
As this input voltage V
CcDuring normal the input, input voltage V
CcBe 1, detect voltage V
DetBe 0, represent the voltage that detects to belong to abnormality, so control signal V
ControlOutput valve is 0, this moment this testing circuit 250 by this switch 220, make these switch 220 not conductings, therefore interrupt this input voltage V
CcProvide voltage to this DC-DC converter 230 and this low drop out voltage regurator 240.That is interrupt all power supply supplies of display panels, avoid liquid crystal under undesired signal, to cause the phenomenon of liquid crystal polarization.
As this input voltage V
CcDuring normal the input, input voltage V
CcBe 1, detect voltage V
DetBe 1, represent the voltage that detects to belong to normal operating conditions, so control signal V
ControlOutput valve is 1, and this moment, this testing circuit 250 was controlled these switch 220 normallies, so this input voltage V
CcNormally provide voltage to this DC-DC converter 230 and this low drop out voltage regurator 240.
This testing circuit 250 can be used for detecting this output voltage V
Aa, when detecting this DC-DC converter 230 stop supplies power supply or this output voltage V
AaExceed this output voltage V
AaThe normal operating voltage scope is then ended this switch 220, makes these switch 220 not conductings, therefore interrupts this input voltage V
CcProvide voltage to this DC-DC converter 230 and this low drop out voltage regurator 240.That is interrupt all power supply supplies of display panels, avoid liquid crystal under undesired signal, to cause the phenomenon of liquid crystal polarization.
This testing circuit 250 can also be used for detecting the output signal of this time schedule controller, exports under abnormal control signal situation when this time schedule controller, then this switch 220 is ended, and makes these switch 220 not conductings, therefore interrupts this input voltage V
CcProvide voltage to this DC-DC converter 230 and this low drop out voltage regurator 240.That is interrupt all power supply supplies of display panels, avoid liquid crystal under undesired signal, to cause the phenomenon of liquid crystal polarization.
In addition, this testing circuit 250 can be used for detecting the output voltage of this low drop out voltage regurator 240, when this output voltage V
DdExceed this output voltage V
DdThe normal operating voltage scope is then ended this switch 220, makes these switch 220 not conductings, therefore interrupts this input voltage V
CcProvide voltage to this DC-DC converter 230 and this low drop out voltage regurator 240.That is interrupt all power supply supplies of display panels, avoid liquid crystal under undesired signal, to cause the phenomenon of liquid crystal polarization.
With reference to shown in Figure 3, it is the DC-DC converter output voltage detection holding circuit synoptic diagram that is applied to prevent in the liquid crystal indicator liquid crystal polarization of the application's second preferred embodiment.As shown in Figure 3, switch 320 is electrically connected the input voltage V of external circuit via fuse 310
CcThis DC-DC converter 330 is electrically connected this switch 320, receives the input voltage V from external circuit
CcCarry out DC voltage and be converted to output voltage V
Aa, this output voltage V
AaProvide to back level dc conversion modules (for example: charge pump circuit is not shown on the figure) and data drive circuit (not being shown on the figure).This back level dc conversion modules is with this output voltage V
AaBe converted into the required grid operating voltage of scan drive circuit.The input voltage V that low drop out voltage regurator 340 receives from external circuit
CcCarry out voltage-regulation, and then provide operating voltage V to the time schedule controller (not being shown on the figure) of this liquid crystal indicator
DdTesting circuit 350 is electrically connected the output terminal of this DC-DC converter 330, is used to detect this output voltage V
AaWhether in normal operating conditions or exceed this output voltage V
AaThe normal operating voltage scope.
When this testing circuit 350 detects this DC-DC converter 330 stop supplies power supply or this output voltage V
AaExceed this output voltage V
AaThe normal operating voltage scope, then this testing circuit 350 utilizes control signal V
ControlThis switch 320 is ended, make these switch 320 not conductings, therefore interrupt this input voltage V
CcProvide voltage to this DC-DC converter 330 and this low drop out voltage regurator 340.That is interrupt all power supply supplies of display panels, avoid liquid crystal under undesired signal, to cause the phenomenon of liquid crystal polarization.
In this preferred embodiment, this testing circuit 350 is incorporated in the pulse-width modulation integrated circuit (PWM IC) 360 with this DC-DC converter 330.
With reference to shown in Figure 4, it is the time schedule controller output signal detection holding circuit synoptic diagram that is applied to prevent in the liquid crystal indicator liquid crystal polarization of the application's the 3rd preferred embodiment.As shown in Figure 4, switch 420 is electrically connected the input voltage V of external circuit via fuse 410
CcThis DC-DC converter 430 is electrically connected this switch 420, receives the input voltage V from external circuit
CcCarry out DC voltage and be converted to output voltage V
Aa, this output voltage V
AaProvide to back level dc conversion modules (for example: charge pump circuit is not shown on the figure) and data drive circuit (not being shown on the figure).This back level dc conversion modules is with this output voltage V
AaBe converted into the required grid operating voltage of scan drive circuit.The input voltage V that low drop out voltage regurator 440 receives from external circuit
CcCarry out voltage-regulation, and then provide operating voltage V to the time schedule controller 460 of this liquid crystal indicator
DdTesting circuit 450 is electrically connected the output terminal of this time schedule controller 460, is used to detect this time schedule controller 460 output signal S
TriggerWhether in normal operating conditions.
Export under abnormal control signal situation when this testing circuit 450 detects this time schedule controller, then this testing circuit 450 utilizes control signal V
ControlThis switch 420 is ended, make these switch 420 not conductings, therefore interrupt this input voltage V
CcProvide voltage to this DC-DC converter 430 and this low drop out voltage regurator 440.That is interrupt all power supply supplies of display panels, avoid liquid crystal under undesired signal, to cause the phenomenon of liquid crystal polarization.
In this preferred embodiment, this testing circuit 450 can be incorporated in the pulse-width modulation integrated circuit 470 with this DC-DC converter 430.
With reference to shown in Figure 5, it is the low drop out voltage regurator output voltage detection holding circuit synoptic diagram that is applied to prevent in the liquid crystal indicator liquid crystal polarization of the application's the 4th preferred embodiment.As shown in Figure 5, switch 520 is electrically connected the input voltage V of external circuit via fuse 510
CcThis DC-DC converter 530 is electrically connected this switch 520, receives the input voltage V from external circuit
CcCarry out DC voltage and be converted to output voltage V
Aa, this output voltage V
AaProvide to back level dc conversion modules (for example: charge pump circuit is not shown on the figure) and data drive circuit (not being shown on the figure).This back level dc conversion modules is with this output voltage V
AaBe converted into the required grid operating voltage of scan drive circuit.The input voltage V that low drop out voltage regurator 540 receives from external circuit
CcCarry out voltage-regulation, and then provide operating voltage V to the time schedule controller (not being shown on the figure) of this liquid crystal indicator
DdTesting circuit 550 is electrically connected the output terminal of this low drop out voltage regurator 540, whether is used to detect the output voltage of this low drop out voltage regurator 540 in normal operating conditions.
The output voltage that detects this low drop out voltage regurator 540 when this testing circuit 550 exceeds this output voltage V
DdDuring the normal operating voltage scope, then this testing circuit 550 utilizes control signal V
ControlThis switch 520 is ended, make these switch 520 not conductings, therefore interrupt this input voltage V
CcProvide voltage to this DC-DC converter 530 and this low drop out voltage regurator 540.That is interrupt all power supply supplies of display panels, avoid liquid crystal under undesired signal, to cause the phenomenon of liquid crystal polarization.
With reference to shown in Figure 6, it is the detection holding circuit synoptic diagram that is applied to prevent in the liquid crystal indicator liquid crystal polarization of the application's the 5th preferred embodiment.As shown in Figure 6, switch 620 is electrically connected the input voltage V of external circuit via fuse 610
CcThis DC-DC converter 630 is electrically connected this switch 620, receives the input voltage V from external circuit
CcCarry out DC voltage and be converted to output voltage V
Aa, this output voltage V
AaProvide to back level dc conversion modules (for example: charge pump circuit is not shown on the figure) and data drive circuit (not being shown on the figure).This back level dc conversion modules is with this output voltage V
AaBe converted into the required grid operating voltage of scan drive circuit.The input voltage V that low drop out voltage regurator 640 receives from external circuit
CcCarry out voltage-regulation, and then provide operating voltage V to the time schedule controller 660 of this liquid crystal indicator
DdTesting circuit 650 is electrically connected the output terminal of this time schedule controller 660, the output terminal of this DC-DC converter 630 and the output terminal of this low drop out voltage regurator 640 respectively, is used to detect this time schedule controller 660 output signal S
TriggerWhether in normal operating conditions, detect this output voltage V
AaWhether in normal operating conditions or exceed this output voltage V
AaWhether normal operating voltage scope or the output voltage that detects this low drop out voltage regurator 640 be in normal operating conditions.
Export under abnormal control signal situation when this testing circuit 650 detects this time schedule controller, then this testing circuit 650 utilizes control signal V
ControlThis switch 620 is ended, make these switch 620 not conductings, therefore interrupt this input voltage V
CcProvide voltage to this DC-DC converter 630 and this low drop out voltage regurator 640.That is interrupt all power supply supplies of display panels, avoid liquid crystal under undesired signal, to cause the phenomenon of liquid crystal polarization.
The output voltage that detects this low drop out voltage regurator 640 when this testing circuit 650 exceeds this output voltage V
DdDuring the normal operating voltage scope, then this testing circuit 650 utilizes control signal V
ControlThis switch 620 is ended, make these switch 620 not conductings, therefore interrupt this input voltage V
CcProvide voltage to this DC-DC converter 630 and this low drop out voltage regurator 640.That is interrupt all power supply supplies of display panels, avoid liquid crystal under undesired signal, to cause the phenomenon of liquid crystal polarization.
When this testing circuit 650 detects this DC-DC converter 630 stop supplies power supply or this output voltage V
AaExceed this output voltage V
AaThe normal operating voltage scope, then this testing circuit 650 utilizes control signal V
ControlThis switch 620 is ended, make these switch 620 not conductings, therefore interrupt this input voltage V
CcProvide voltage to this DC-DC converter 630 and this low drop out voltage regurator 640.That is interrupt all power supply supplies of display panels, avoid liquid crystal under undesired signal, to cause the phenomenon of liquid crystal polarization.
In this preferred embodiment, this testing circuit 650, this DC-DC converter 630 and this low drop out voltage regurator 640 can be incorporated in the pulse-width modulation integrated circuit 670.
Comprehensively above-mentioned; the invention provides the detection holding circuit that is applied to prevent in the liquid crystal indicator liquid crystal polarization; under the undesired supply voltage condition of the low drop out voltage regurator of liquid crystal indicator; under the undesired supply voltage condition of DC-DC converter or time schedule controller normally provides under the power supply situation at this low drop out voltage regurator and this DC-DC converter; export abnormal scan control signal or data controlling signal and give scan drive circuit or data drive circuit; this testing circuit can be closed the input voltage that offers this liquid crystal indicator from external circuit, avoids liquid crystal causing liquid crystal to cause the phenomenon of liquid crystal polarization under the undesired signal under long-time stress.
Specific embodiment of the invention described above and diagram are to make those skilled in the art can understand the present invention, yet the interest field of this patent is not limited to the foregoing description.
Comprehensively above-mentioned, purpose of the present invention fully and effectively is disclosed.The application can make multiple modification by those skilled in the art, but neither disengaging such as claims Protector that scope is desired.