Liquid crystal display device and test method therefor
An exemplary liquid crystal display device includes scanning lines ( 201 ), data lines ( 202 ), and a control circuit ( 200 ). The control circuit includes a data driver ( 230 ), a scanning driver ( 220 ), and a DC/DC converter ( 260 ). The DC/DC converter includes a reference voltage output terminal ( 262 ), a high voltage output terminal ( 263 ), a low voltage output terminal ( 264 ), a first adjusting circuit connected to the reference voltage output terminal, a second adjusting circuit connected to the high voltage output terminal and a third adjusting circuit connected to low voltage output terminal. The first adjusting circuit includes a first terminal. The second adjusting circuit includes a second terminal. The third adjusting circuit includes a third terminal. Three voltages of the three output terminals are determined by three voltages of the three terminals of the three adjusting circuits.
1 . A liquid crystal display device, comprising:
a plurality of scanning lines;
a plurality of data lines; and
a control circuit, comprising:
a data driver;
a scanning driver; and
a direct current to direct current (DC/DC) converter, comprising:
an analog voltage output terminal capable of outputting a reference voltage;
a high voltage output terminal capable of outputting a high-level voltage;
a low voltage output terminal capable of outputting a low-level voltage;
a first adjusting circuit connected to the analog voltage output terminal;
a second adjusting circuit connected to the high voltage output terminal; and
a third adjusting circuit connected to the low voltage output terminal;
the scanning driver being configured to receive the high-level voltage and the low-level voltage, and output a plurality of scanning voltages to each scanning line in turn; and the data driver being configured to receive the reference voltage, and output a plurality of gray voltages to the data lines;
wherein, the first adjusting circuit comprises a first terminal, the second adjusting circuit comprises a second terminal, and the third adjusting circuit comprises a third terminal, three voltages of the three output terminals being determined by three voltages of the three terminals of the three adjusting circuits.
2 . The liquid crystal display device of claim 1 , wherein the DC/DC converter further comprises a step-up transformer, the step-up transformer comprises a reference terminal, a first feedback terminal, a second feedback terminal, and a third feedback terminal, the first adjusting circuit further comprises a first resistor, a fourth resistor, and a fifth resistor, one terminal of the first resistor is connected to the first feedback terminal, the other terminal of the first resistor is floating, the analog voltage output terminal is grounded via the fourth resistor and the fifth resistor in series, the first feedback terminal is connected to a node between the fourth resistor and the fifth resistor, the second adjusting circuit further comprises a second resistor, a sixth resistor, and a seventh resistor, one terminal of the second resistor is connected to the second feedback terminal, the other terminal of the second resistor is floating, the high voltage output terminal is grounded via the sixth resistor and the seventh resistor in series, the second feedback terminal is connected to a node between the sixth resistor and the seventh resistor, the third adjusting circuit further comprises a third resistor, an eighth resistor and a ninth resistor, one terminal of the third resistor is connected to the third feedback terminal, the other terminal of the third resistor is floating, the low voltage output terminal is connected to the reference terminal via the eighth resistor and the ninth resistor in series, the third feedback terminal is connected to a node between the eighth resistor and the ninth resistor, the first terminal is the floating terminal of the first resistor, the second terminal is the floating terminal of the second resistor, and the third terminal is the floating terminal of the third resistor.
3 . The liquid crystal display device of claim 2 , wherein the DC/DC converter further comprises a voltage input terminal capable of being connected to a five volt power supply.
4 . The liquid crystal display device of claim 3 , wherein the DC/DC converter further comprises a step-up unit, and the voltage input terminal is connected to the analog voltage output terminal via the step-up unit.
5 . The liquid crystal display device of claim 4 , wherein the DC/DC converter further comprises a first charge pump and a first step-down circuit, the first charge pump is configured to double the reference voltage, and the first step-down circuit is configured to transform the doubled reference voltage to the high-level voltage and provide the high-level voltage to the high voltage output terminal.
6 . The liquid crystal display device of claim 5 , wherein the step-up transformer further comprises a first modulation terminal, the first step-down circuit comprises a positive-negative-positive (PNP) semiconductor triode, a base electrode of the PNP semiconductor triode is connected to the first modulation terminal, an emitter electrode of the PNP semiconductor triode is connected to the analog voltage output terminal via the first charge pump, and a collector electrode of the PNP semiconductor triode is connected to the high-level voltage output terminal.
7 . The liquid crystal display device of claim 5 , wherein the DC/DC converter further comprises a second charge pump and a second step-down circuit, the second charge pump is configured to transform the reference voltage to a negative reference voltage, and the second step-down circuit is configured to transform the negative reference voltage to the low-level voltage and provide the low-level voltage to the low voltage output terminal.
8 . The liquid crystal display device of claim 7 , wherein the step-up transformer further comprises a second modulation terminal, the second step-down circuit comprises a negative-positive-negative (NPN) semiconductor triode, a base electrode of the NPN semiconductor triode is connected to the second modulation terminal, an emitter electrode of the NPN semiconductor triode is connected to the reference voltage output terminal via the second charge pump and the first charge pump in turn, and a collector electrode of the NPN semiconductor triode is connected to the low voltage output terminal.
9 . The liquid crystal display device of claim 1 , wherein the DC/DC converter further comprises a step-up transformer, the step-up transformer comprises a reference terminal, a first feedback terminal, a second feedback terminal, and a third feedback terminal, the first adjusting circuit further comprises a first switch, a first resistor, a fourth resistor, and a fifth resistor, one terminal of the first resistor is connected to the first feedback terminal, the other terminal of the first resistor is grounded via the first switch, the reference voltage output terminal is grounded via the fourth resistor and the fifth resistor in series, the first feedback terminal is connected to a node between the fourth resistor and the fifth resistor, the second adjusting circuit further comprises a second switch, a second resistor, a sixth resistor, and a seventh resistor, one terminal of the second resistor is connected to the second feedback terminal, the other terminal of the second resistor is grounded via the second switch, the high voltage output terminal is grounded via the sixth resistor and the seventh resistor in series, the second feedback terminal is connected to a node between the sixth resistor and the seventh resistor, the third adjusting circuit further comprises a third switch, a third resistor, an eighth resistor, and a ninth resistor, one terminal of the third resistor is connected to the third feedback terminal, the other terminal of the third resistor is connected to the reference terminal via the third switch, the low voltage output terminal is connected to the reference terminal via the eighth resistor and the ninth resistor in series, the third feedback terminal is connected to a node between the eighth resistor and the ninth resistor, and three control terminals of the three switches are the three terminals of the three adjusting circuits.
10 . The liquid crystal display device of claim 9 , wherein the first switch comprises a transistor, a gate electrode of the first switch is floating, a source electrode of the first switch is grounded, and a drain electrode of the first switch is connected to the first feedback terminal via the first resistor.
11 . The liquid crystal display device of claim 10 , wherein the second switch comprises a transistor, a gate electrode of the second switch is floating, a source electrode of the second switch is grounded, and a drain electrode of the second switch is connected to the second feedback terminal via the second resistor.
12 . The liquid crystal display device of claim 11 , wherein the third switch comprises a transistor, a gate electrode of the third switch is floating, a source electrode of the third switch is connected to the reference terminal, and a drain electrode of the third switch is connected to the third feedback terminal via the third resistor.
13 . A test method for the liquid crystal display device of claim 1 , the method comprising:
providing an operating voltage for the control circuit;
connecting a connector to the control circuit, the connector comprising a first connecting terminal, a second connecting terminal, and a third connecting terminal, the three connecting terminals being respectively connected to the three terminals of the three adjusting circuits; and
controlling voltages of the three output terminals by controlling the three voltages of the three connecting terminals.
14 . The test method of claim 13 , wherein the DC/DC converter further comprises a step-up transformer, the step-up transformer comprises a reference terminal, a first feedback terminal, a second feedback terminal, and a third feedback terminal, the first adjusting circuit further comprises a first resistor, a fourth resistor, and a fifth resistor, one terminal of the first resistor is connected to the first feedback terminal, the other terminal of the first resistor is floating, the analog voltage output terminal is grounded via the fourth resistor and the fifth resistor in series, the first feedback terminal is connected to a node between the fourth resistor and the fifth resistor, the second adjusting circuit further comprises a second resistor, a sixth resistor, and a seventh resistor, one terminal of the second resistor is connected to the second feedback terminal, the other terminal of the second resistor is floating, the high voltage output terminal is grounded via the sixth resistor and the seventh resistor in series, the second feedback terminal is connected to a node between the sixth resistor and the seventh resistor, the third adjusting circuit further comprises a third resistor, an eighth resistor and a ninth resistor, one terminal of the third resistor is connected to the third feedback terminal, the other terminal of the third resistor is floating, the low voltage output terminal is connected to the reference terminal via the eighth resistor and the ninth resistor in series, the third feedback terminal is connected to a node between the eighth resistor and the ninth resistor, the first terminal is the floating terminal of the first resistor, the second terminal is the floating terminal of the second resistor, the third terminal is the floating terminal of the third resistor, and in the test method, the first connecting terminal and the second connecting terminal are grounded, and the third connecting terminal is connected to a voltage which is equal to a voltage of the reference terminal.
15 . The test method of claim 14 , wherein the liquid crystal display device further comprises a timing controller and a test system, the timing controller is configured to receive an external low voltage differential signal and output a plurality of digital signals to the data driver, the connector further comprises an output terminal connected to the timing controller, and the output terminal is capable of providing an enabling signal that enables the test system of the liquid crystal display device to display a predetermined test picture.
16 . The test method of claim 13 , wherein the DC/DC converter further comprises a step-up transformer, the step-up transformer comprises a reference terminal, a first feedback terminal, a second feedback terminal, and a third feedback terminal, the first adjusting circuit further comprises a first switch, a first resistor, a fourth resistor, and a fifth resistor, one terminal of the first resistor is connected to the first feedback terminal, the other terminal of the first resistor is grounded via the first switch, the reference voltage output terminal is grounded via the fourth resistor and the fifth resistor in series, the first feedback terminal is connected to a node between the fourth resistor and the fifth resistor, the second adjusting circuit further comprises a second switch, a second resistor, a sixth resistor, and a seventh resistor, one terminal of the second resistor is connected to the second feedback terminal, the other terminal of the second resistor is grounded via the second switch, the high voltage output terminal is grounded via the sixth resistor and the seventh resistor in series, the second feedback terminal is connected to a node between the sixth resistor and the seventh resistor, the third adjusting circuit further comprises a third switch, a third resistor, an eighth resistor, and a ninth resistor, one terminal of the third resistor is connected to the third feedback terminal, the other terminal of the third resistor is connected to the reference terminal via the third switch, the low voltage output terminal is connected to the reference terminal via the eighth resistor and the ninth resistor in series, the third feedback terminal is connected to a node between the eighth resistor and the ninth resistor, three control terminals of the three switches are the three terminals of the three adjusting circuits, and the test method further comprises turning on the three switches through control of the three voltages of the three connecting terminals.
17 . The test method of claim 16 , wherein the liquid crystal display device further comprises a timing controller and a test system, the timing controller is configured to receive an external low voltage differential signal and output a plurality of digital signals to the data driver, the connector further comprises an output terminal connected to the timing controller, and the output terminal is capable of providing an enabling signal that enables the test system of the liquid crystal display device to display a predetermined test picture.
18 . A liquid crystal display device, comprising:
a plurality of scanning lines;
a plurality of data lines; and
a control circuit, comprising:
a data driver;
a scanning driver; and
a direct current to direct current (DC/DC) converter, comprising:
an analog voltage output terminal capable of outputting a reference voltage;
a high voltage output terminal capable of outputting a high-level voltage;
a low voltage output terminal capable of outputting a low-level voltage;
a first adjusting circuit connected to the analog voltage output terminal;
a second adjusting circuit connected to the high voltage output terminal; and
a third adjusting circuit connected to the low voltage output terminal;
the scanning driver being configured to receive the high-level voltage and the low-level voltage, and output a plurality of scanning voltages to each scanning line in turn; and the data driver being configured to receive the reference voltage, and output a plurality of gray voltages to the data lines;
wherein, three voltages of the three output terminals are determined by three resistances of the three adjusting circuits.
19 . The liquid crystal display device of claim 18 , wherein the DC/DC converter further comprises a step-up transformer, the step-up transformer comprises a first feedback terminal, a second feedback terminal, and a third feedback terminal, the first adjusting circuit comprises a first feedback circuit and a first resistor, the first feedback circuit is configured to feed back a voltage of the analog voltage output terminal to the first feedback terminal, one terminal of the first resistor is connected to the first feedback terminal, the other terminal of the first resistor is floating, the second adjusting circuit comprises a second feedback circuit and a second resistor, the second feedback circuit is configured to feed back a voltage of the high voltage output terminal to the second feedback terminal, one terminal of the second resistor is connected to the second feedback terminal, the other terminal of the second resistor is floating, the third adjusting circuit comprises a third feedback circuit and a third resistor, the third feedback circuit is configured to feed back a voltage of the low voltage output terminal to the third feedback terminal, one terminal of the third resistor is connected to the third feedback terminal, the other terminal of the third resistor is floating, and three resistances of the three feedback circuits are determined by three voltages of the three floating terminals.
20 . The liquid crystal display device of claim 18 , wherein the DC/DC converter further comprises a step-up transformer, the step-up transformer comprises a reference terminal, a first feedback terminal, a second feedback terminal, and a third feedback terminal, the first adjusting circuit comprises a first switch, a first resistor, and a first feedback circuit, the first feedback circuit is configured to feed back a voltage of the analog voltage output terminal to the first feedback terminal, one terminal of the first resistor is connected to the first feedback terminal, the other terminal of the first resistor is grounded via the first switch, the second adjusting circuit comprises a second switch, a second resistor, and a second feedback circuit, the second feedback circuit is configured to feed back a voltage of the high voltage output terminal to the second feedback terminal, one terminal of the second resistor is connected to the second feedback terminal, the other terminal of the second resistor is grounded via the second switch, the third adjusting circuit comprises a third switch, a third resistor, and a third feedback circuit, the third feedback circuit is configured to feed back a voltage of the low voltage output terminal to the third feedback terminal, one terminal of the third resistor is connected to the third feedback terminal, the other terminal of the third resistor is connected to the reference terminal via the third switch, and three resistances of the three feedback circuits are determined by three voltages of three control terminals of the three switches.