Voltage compensation circuit of LCD (liquid crystal display) and LCD

Abstract

The embodiment of the utility model provides a voltage compensation circuit of an LCD (Liquid Crystal Display) and an LCD display. The voltage compensation circuit of the LCD comprises a temperature sensing circuit, a voltage regulating circuit, an IC (Integrated Circuit) chip and an output circuit, the temperature sensing circuit is used for correspondingly adjusting the voltage dividing resistance of the temperature sensing circuit according to different environment temperatures; the voltage regulation circuit is used for correspondingly regulating the FB feedback voltage of the voltage regulation circuit according to the voltage division resistance value; the IC chip is used for correspondingly adjusting the VGH output voltage of the IC chip according to the FB feedback voltage; and the output circuit is used for outputting the VGH output voltage to a working voltage input end of the LCD display, so that the LCD display has corresponding working voltages at different environment temperatures to maintain normal work of the LCD display. According to the technical scheme, the LCD can have different input voltages (namely VGH output voltages) at different environment temperatures, so that voltage output is stabilized, the circuit design is simplified, temperature changes are responded in real time, and the stability and the adaptive capacity of the circuit are enhanced.

Description

TECHNICAL FIELD

[0001] The utility model relates to a voltage compensation circuit and LCD display of LCD belong to LCD display screen technical field. BACKGROUND

[0002] In modern electronic devices, liquid crystal display (LCD) is widely used in smart phones, tablets, televisions and various industrial control systems due to its excellent visual effect and energy saving characteristics. However, the performance of LCD is significantly affected by environmental temperature changes, especially in the process of voltage supply and signal transmission.

[0003] This is because liquid crystal material is very sensitive to temperature changes, and the increase or decrease of temperature will change the arrangement of liquid crystal molecules and optical properties, thereby affecting the display effect. Under different temperature conditions, the response time, color performance and brightness of LCD may be affected. For example, high temperature environment may cause display color deviation and contrast ratio decrease, while low temperature may slow down the response speed of liquid crystal, and even cause screen instability. These problems not only damage the user experience, but also may cause equipment failure and affect the overall function. At the same time, the voltage signal in the LCD drive circuit is also affected by temperature fluctuation. The working voltage and output signal of the amplifier and converter used in the drive circuit may drift with the change of temperature. If not compensated, this voltage fluctuation will directly lead to the decline of display quality, such as image blur, flicker, etc. Therefore, when designing LCD drive circuit, how to effectively compensate the voltage becomes an important technical challenge.

[0004] Although some temperature compensation techniques exist in the prior art have solved the related problems to some extent, there are still many deficiencies, for example, some software compensation methods may not respond to rapid temperature changes in real time, limiting their effectiveness in dynamic environment. In addition, the adaptability of existing technology under extreme temperature conditions is also limited, which cannot meet the increasing demand for stability in the market. Therefore, a voltage output that can maintain stability under different temperature conditions to ensure the consistency and reliability of LCD display effect has become an urgent demand in the industry. SUMMARY

[0005] Therefore, the utility model provides a kind of voltage compensation circuit and LCD display of LCD.

[0006] In the first aspect, the utility model embodiment provides a kind of voltage compensation circuit of LCD, comprising: temperature sensing circuit, voltage regulating circuit, IC chip and output circuit;

[0007] The temperature sensing circuit is used for adjusting the voltage dividing resistance value of the temperature sensing circuit according to different ambient temperatures.

[0008] The voltage regulating circuit is used for adjusting the FB feedback voltage of the voltage regulating circuit according to the voltage dividing resistance value.

[0009] The IC chip is used for adjusting the VGH output voltage of the IC chip according to the FB feedback voltage.

[0010] The output circuit is used for outputting the VGH output voltage to the working voltage input end of the LCD display, so that the LCD display has corresponding working voltage at different ambient temperatures to maintain the normal working of the LCD display.

[0011] As a preferred embodiment of the utility model, the temperature sensing circuit comprises a thermistor R0, a resistor R1, a resistor R2 and a resistor R3.

[0012] One end of the thermistor R0 is connected to a VDD voltage input end, one end of the resistor R1 and one end of the resistor R3.

[0013] The other end of the thermistor R0 is connected to the other end of the resistor R1, one end of the resistor R2 and the voltage regulating circuit.

[0014] The other end of the resistor R3 is connected to the voltage regulating circuit.

[0015] The other end of the resistor R2 is grounded.

[0016] As a preferred embodiment of the utility model, the voltage regulating circuit comprises a triode BJT1 and a resistor R4.

[0017] One end of the resistor R4 is connected to the other end of the resistor R3.

[0018] The other end of the resistor R4 is connected to the C pole of the triode BJT1.

[0019] The B pole of the triode BJT1 is connected to the other end of the thermistor R0.

[0020] The E pole of the triode BJT1 is grounded.

[0021] As a preferred embodiment of the utility model, one end of the resistor R4 is connected to the FBP pin of the IC chip, and the FB feedback voltage is output to the IC chip.

[0022] As a preferred embodiment of the utility model, the triode BJT1 is an NPN type triode.

[0023] As a preferred embodiment of the utility model, the thermistor R0 is a negative temperature coefficient thermistor, and the resistance value increases with the decrease of the ambient temperature.

[0024] As a preferred embodiment of the utility model, the voltage regulating circuit further comprises resistors R6 and R7.

[0025] One end of the resistor R4 is further connected to the resistors R6 and R7 in sequence and grounded.

[0026] As a preferred embodiment of the utility model, the output circuit comprises a resistor R5 and a VGH output terminal.

[0027] One end of the resistor R5 is connected to the VGH output terminal, and the other end of the resistor R5 is grounded.

[0028] The VGH output terminal is connected to the VGHM pin of the IC chip and the LCD display, and is used to provide the VGH output voltage to the LCD display.

[0029] As a preferred embodiment of the utility model, when the ambient temperature is greater than or equal to 0℃, the temperature sensing circuit is in a low resistance state, so that the transistor BJT1 is in a saturation region, and a 1.25V FB feedback voltage is outputted, and the 1.25V FB feedback voltage makes the IC chip output a 25V VGH output voltage.

[0030] When the ambient temperature is less than 0℃, the temperature sensing circuit is in a high resistance state, and the voltage division resistance of the temperature sensing circuit increases with the decrease of the ambient temperature, so that the transistor BJT1 turns into an amplification region, the FB feedback voltage rises, and the VGH output voltage of the IC chip rises.

[0031] In a second aspect, the utility model further provides a LCD display, comprising the voltage compensation circuit of the LCD in any embodiment of the utility model.

[0032] Compared with the prior art, the utility model has the following beneficial effects:

[0033] The utility model embodiment can achieve the following purposes by the temperature sensing circuit for monitoring the ambient temperature in real time:

[0034] 1. Stable voltage output. By sensing the environmental temperature changes through the temperature sensing circuit, and automatically adjusting the voltage dividing resistance value of the temperature sensing circuit, the FB feedback voltage of the voltage regulating circuit, and the VGH output voltage of the IC chip according to the changes in environmental temperature, it ensures that the LCD can have stable and accurate input voltage (i.e. VGH output voltage) under various temperature conditions, to maintain the consistency of the LCD display effect.

[0035] 2. Simplify circuit design. Reduce the dependence on additional sensors and complex hardware, chips, etc. Use a simpler and more economical circuit design to reduce production costs and improve production efficiency.

[0036] 3. Real-time response to temperature changes. Through the mechanism of real-time monitoring of temperature by the temperature sensing circuit and corresponding adjustment of voltage output, the circuit can quickly respond to temperature changes, ensuring the display quality of the LCD in dynamic environments is not affected.

[0037] 4. Enhance stability and adaptability. Improve the stability and adaptability of the circuit under extreme temperature conditions, allowing it to reliably operate in a wider range of application scenarios, including outdoor, high-temperature or low-temperature environments. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings described below are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained from the structures shown in these drawings without creative labor.

[0039] Fig. 1 A module schematic diagram of the voltage compensation circuit of the LCD in the embodiment of the present application;

[0040] Fig. 2 A circuit diagram of the voltage compensation circuit of the LCD in the embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical scheme in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0042] Embodiment:

[0043] In a first aspect, as shown in the accompanying drawings, the utility model discloses a voltage compensation circuit of LCD, include: temperature sensing circuit 10, voltage regulation circuit 20, IC chip 30 and output circuit 40. Figs. 1-2

[0044] Temperature sensing circuit 10 is used to adjust the voltage division resistance value of temperature sensing circuit 10 correspondingly according to different ambient temperature;

[0045] Voltage regulation circuit 20 is used to adjust the FB feedback voltage of voltage regulation circuit 20 correspondingly according to the voltage division resistance value;

[0046] IC chip 30 is used to adjust the VGH output voltage of IC chip 30 correspondingly according to the FB feedback voltage;

[0047] Output circuit 40 is used to output the VGH output voltage to the working voltage input end of LCD display, so that the LCD display has corresponding working voltage under different ambient temperature, to maintain the normal work of LCD display.

[0048] The utility model embodiment through temperature sensing circuit senses environmental temperature change, and according to the change of environmental temperature, automatically adjusts the voltage division resistance value of temperature sensing circuit, the FB feedback voltage of voltage regulation circuit and the VGH output voltage of IC chip, so that the LCD can have different input voltage (namely VGH output voltage) under different environmental temperature, thereby improving the stability of LCD circuit under extreme temperature condition, and simplifying circuit design, reduce production cost and improve production efficiency;Quick response to temperature change, ensure that the display quality of LCD under dynamic environment is not influenced;The stability and adaptability of circuit under extreme temperature condition are improved, so that it can reliably run in more extensive application scenarios, including outdoor, high temperature or low temperature environment.

[0049] As a preferred embodiment of the utility model, temperature sensing circuit 10 includes thermistor R0, resistance R1, resistance R2 and resistance R3;

[0050] One end of thermistor R0 is connected to VDD voltage input end, one end of resistance R1 and one end of resistance R3;

[0051] The other end of thermistor R0 is connected to the other end of resistance R1, one end of resistance R2 and voltage regulation circuit;

[0052] The other end of resistance R3 is connected to voltage regulation circuit 20;

[0053] The other end of resistance R2 is grounded. ​

[0054] The embodiment of the utility model discloses through the resistance of thermistor R0 real-time response surrounding temperature change. When temperature changes, the resistance of thermistor R0 also will change along with it, thereby influence temperature sensing circuit's partial pressure resistance, and then influence the VGH output voltage of whole LCD's voltage compensation circuit. Among them, the VDD voltage input end is connected with +3.3V voltage.

[0055] As a preferred embodiment of the utility model, the voltage regulating circuit 20 includes a transistor BJT1 and a resistor R4.

[0056] One end of the resistor R4 is connected to the other end of the resistor R3.

[0057] The other end of the resistor R4 is connected to the C pole (collector) of the transistor BJT1.

[0058] The B pole (base) of the transistor BJT1 is connected to the other end of the resistance of thermistor R0.

[0059] The E pole (emitter) of the transistor BJT1 is grounded.

[0060] As a preferred embodiment of the utility model, one end of the resistor R4 is connected to the FBP pin of the IC chip for outputting the FB feedback voltage to the IC chip.

[0061] In the embodiment of the utility model, the FB feedback voltage output by the voltage regulating circuit is adjusted according to the conduction state of the transistor BJT1, and the FB feedback voltage is output at one end of the resistor R4 and connected to the IC chip for providing the FB feedback voltage to the IC chip.

[0062] As a preferred embodiment of the utility model, the transistor BJT1 is an NPN type transistor.

[0063] As a preferred embodiment of the utility model, the resistance of thermistor R0 is a negative temperature coefficient thermistor, which increases the resistance value as the ambient temperature decreases.

[0064] Preferably, when the ambient temperature is higher than 0℃, the resistance of thermistor R0 is low, and when the temperature decreases, the resistance increases. In the embodiment of the utility model, other resistors in the circuit, such as resistors R1, R2 and R3, need to be properly configured according to the change of the resistance of thermistor R0 to ensure the accurate setting of the B pole voltage of the transistor BJT1, which will directly affect the conduction state of the transistor BJT1.

[0065] As a preferred embodiment of the utility model, the voltage regulating circuit 20 further includes a resistor R6 and a resistor R7.

[0066] One end of the resistor R4 is connected to one end of the resistor R6 in turn, and the other end of the resistor R6 is connected to one end of the resistor R7 in turn, and the other end of the resistor R7 is grounded.

[0067] The resistor R6 and the resistor R7 in the embodiment of the utility model can play a role of voltage division, and the resistance value thereof can be set as required to adjust the size of the FB feedback voltage.

[0068] As a preferred embodiment of the utility model, the output circuit 40 comprises a resistor R5 and a VGH output end;

[0069] One end of the resistor R5 is connected to the VGH output end, and the other end of the resistor R5 is grounded.

[0070] The VGH output end is connected to the VGHM pin of the IC chip and the LCD display, and is used for providing the VGH output voltage to the LCD display.

[0071] The resistor R5 in the embodiment of the utility model can play a role of voltage division, and the resistance value thereof can be set as required to adjust the voltage in the circuit.

[0072] As a preferred embodiment of the utility model, the temperature sensing circuit is in a low resistance value state when the ambient temperature is greater than or equal to 0 DEG C, so that the triode BJT1 is in a saturation region, and a FB feedback voltage of 1.25V is output, and the FB feedback voltage of 1.25V makes the IC chip output a VGH output voltage of 25V;

[0073] The temperature sensing circuit is in a high resistance value state when the ambient temperature is less than 0 DEG C, and the voltage division resistance value of the temperature sensing circuit is increased with the decrease of the ambient temperature, so that the triode BJT1 is turned into an amplification region, the FB feedback voltage is increased, and the VGH output voltage of the IC chip is increased.

[0074] Specifically, the working principle of the voltage compensation circuit of the LCD in the embodiment of the utility model is as follows:

[0075] When the ambient temperature is kept greater than or equal to 0 DEG C, the resistance value of the thermistor R0 is low, that is, the temperature sensing circuit is in a low resistance value state, so that the triode BJT1 is in a saturation region, at this time, the triode BJT1 is completely turned on, at this time, the collector current (Ice) of the triode BJT1 remains relatively stable, and the collector-emitter voltage (Uce) of the triode BJT1 will also be constant at a lower value. Under this condition, the FB feedback voltage is preferably output as 1.25V, and the IC chip will control the VGH output voltage of 25V output by the FB feedback voltage of 1.25V to maintain the normal work of the liquid crystal display.

[0076] When the ambient temperature is less than 0 DEG C and gradually decreases, the resistance of the thermistor R0 will increase with the decrease of the ambient temperature, the temperature sensing circuit will be in a high resistance state, and the voltage dividing resistance of the temperature sensing circuit will increase with the decrease of the ambient temperature, so that the B electrode voltage of the triode BJT1 decreases and gradually transfers from the saturation region to the amplification region. In the amplification region, the Ice current begins to decrease, the Uce voltage decreases, and the FB feedback voltage increases with the decrease of the Ice, thereby forming a feedback mechanism, so that the IC chip automatically increases the VGH output voltage after receiving the increased FB feedback voltage, to compensate for the performance decrease of the circuit caused by the low temperature. The specific VGH output voltage, FB feedback voltage and the related changes of the ambient temperature can be determined according to the specific LCD display product, and in the embodiment of the utility model, the VGH output voltage can be increased to 30V or higher with the decrease of the ambient temperature, to ensure that the liquid crystal display can still provide clear and stable display effect at low temperature.

[0077] In the second aspect, the utility model also provides a LCD display, including the voltage compensation circuit of LCD as any embodiment of the utility model.

[0078] The above is only the preferred embodiment of the utility model patent, but the protection scope of the utility model patent is not limited to this, any skilled person in the art can make equivalent replacement or change according to the technical scheme and the utility model concept of the utility model patent within the range disclosed by the utility model patent, which all belong to the protection scope of the utility model patent.

Claims

1. A voltage compensation circuit for an LCD, characterized by, The voltage compensation circuit comprises a temperature sensing circuit, a voltage regulating circuit, an IC chip and an output circuit. The temperature sensing circuit is used to adjust the voltage dividing resistance of the temperature sensing circuit according to different ambient temperatures. The voltage regulating circuit is used to adjust the FB feedback voltage of the voltage regulating circuit according to the voltage dividing resistance. The IC chip is used to adjust the VGH output voltage of the IC chip according to the FB feedback voltage. The output circuit is used to output the VGH output voltage to the working voltage input end of the LCD display, so that the LCD display has corresponding working voltage at different ambient temperatures to maintain the normal working of the LCD display. The temperature sensing circuit comprises a thermistor R0, a resistor R1, a resistor R2 and a resistor R3.

2. The voltage compensation circuit for an LCD as recited in claim 1, wherein, One end of the thermistor R0 is connected to a VDD voltage input end, one end of the resistor R1 and one end of the resistor R3. The other end of the thermistor R0 is connected to the other end of the resistor R1, one end of the resistor R2 and the voltage regulating circuit. The other end of the resistor R3 is connected to the voltage regulating circuit. The other end of the resistor R2 is grounded. The voltage regulating circuit comprises a transistor BJT1 and a resistor R4.

3. The voltage compensation circuit for an LCD as defined in claim 2, wherein One end of the resistor R4 is connected to the other end of the resistor R3. The other end of the resistor R4 is connected to the C pole of the transistor BJT1. The B pole of the transistor BJT1 is connected to the other end of the thermistor R0. The E pole of the transistor BJT1 is grounded. One end of the resistor R4 is connected to the FBP pin of the IC chip for outputting the FB feedback voltage to the IC chip.

4. The voltage compensation circuit for an LCD as defined in claim 3, wherein The transistor BJT1 is an NPN type transistor.

5. The voltage compensation circuit for an LCD as defined in claim 4, wherein, The thermistor R0 is a negative temperature coefficient thermistor which increases the resistance value as the ambient temperature decreases.

6. The voltage compensation circuit for an LCD as claimed in claim 5, characterized in that, 7. The voltage compensation circuit of the LCD according to claim 3, wherein The voltage regulating circuit further comprises a resistor R6 and a resistor R7. One end of the resistor R4 is further connected to the resistor R6 and the resistor R7 in sequence and then grounded. The output circuit comprises a resistor R5 and a VGH output end.

8. The voltage compensation circuit for an LCD as claimed in claim 6, characterized in that, One end of the resistor R5 is connected to the VGH output end, and the other end of the resistor R5 is grounded. The VGH output end is connected to the LCD display and the VGHM pin of the IC chip for providing the VGH output voltage to the LCD display.

9. The voltage compensation circuit of the LCD according to claim 8, wherein When the ambient temperature is greater than or equal to 0℃, the temperature sensing circuit is in a low resistance state, so that the transistor BJT1 is in a saturation region, and outputs a FB feedback voltage of 1.25V, and the FB feedback voltage of 1.25V makes the IC chip output a VGH output voltage of 25V. ​ The temperature sensing circuit is in a high resistance state when the ambient temperature is less than 0℃, and the partial pressure resistance value of the temperature sensing circuit is increased with the decrease of the ambient temperature, so that the transistor BJT1 turns into the amplification zone, the FB feedback voltage rises, and the VGH output voltage of the IC chip is increased.

10. An LCD display, characterized by The LCD display includes the voltage compensation circuit of the LCD of any one of claims 1-9.

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