LCD module temperature detection device

Abstract

The utility model discloses an LCD module temperature detection device, the LCD module comprises a backlight module, the backlight module comprises a thermistor, the LCD module comprises an upper computer module, a main control module, a constant current source module and an LCD module, the upper computer module is in communication connection with the main control module, the main control module is respectively and electrically connected with the output end of the constant current source module and the positive electrode end of the thermistor, and the constant current source module is electrically connected with the LCD module. The negative electrode end of the thermistor is connected to the GND end of the constant current source module. The master control module comprises an ADC module and is used for collecting the voltage of the output end of the constant current source, converting the voltage into digital quantity information and uploading the digital quantity information to the upper computer module.

Description

TECHNICAL FIELD

[0001] The utility model relates to digital signal processing technical field, concretely relates to a LCD module temperature detection device. BACKGROUND

[0002] Liquid crystal display, English abbreviation is LCD full name is Liquid Crystal Display, it belongs to the kind of flat panel display. It is commonly used in mobile phone, industrial computer, vehicle, television and computer screen display. The advantages of the display screen are low power consumption, small size, low radiation.

[0003] Because liquid crystal itself cannot spontaneously emit light, the LCD liquid crystal display screen also needs to increase the LED backlight. The LCD module usually refers to a whole that is combined by the liquid crystal display and the LED backlight module. The temperature of the LED backlight module is relatively high when it is lit for a long time, and the temperature needs to be detected in real time. The LED backlight module generally integrates a thermistor for temperature detection. The traditional detection scheme is to use a constant voltage power supply to supply power, and to detect the voltage and current of the thermistor, and then to calculate the resistance value and the corresponding temperature of the thermistor. The traditional detection scheme is affected by the power supply ripple, temperature drift, and sampling accuracy error of voltage and current, which can cause large temperature error in detection. At the same time, the cost of the traditional detection scheme is also large. SUMMARY

[0004] In order to overcome the above-mentioned shortcomings, the purpose of the utility model is to provide a LCD module temperature detection device to solve the problem of large error caused by the influence of power supply ripple and temperature drift in the constant voltage power supply detection of thermistor in the background technology.

[0005] In order to achieve the above purpose, the utility model adopts the technical scheme of a LCD module temperature detection device, the LCD module includes a backlight module, the backlight module includes a thermistor, and includes an upper computer module, a main control module, a constant current source module and an LCD module. The upper computer module is in communication connection with the main control module, the main control module is respectively in electrical connection with the output end of the constant current source module and the positive electrode end of the thermistor, and the negative electrode end of the thermistor is connected to the GND end of the constant current source module. The main control module includes an ADC module for collecting the voltage of the constant current source output end and converting it into digital quantity information uploaded to the upper computer module.

[0006] Preferably, the constant current source module includes a constant current source chip U1 and a first capacitor C1, the constant current source chip U1 includes three pins, the first pin is connected with the power supply end VCC, and the third pin is connected with the positive electrode end of the thermistor. One end of the first capacitor C1 is connected to the node between the first pin and the power supply end VCC, and the other end is grounded, and the VCC is a 5V power supply.

[0007] Preferably, the constant current source module further comprises a setting resistor Rset, two ends of the setting resistor Rset are connected with the second pin and the third pin of the constant current source chip U1 respectively, and the output current of the constant current source chip U1 is adjusted by adjusting the resistance value of the setting resistor Rset.

[0008] Preferably, the setting resistor Rset is a resistor with a precision of one thousandth, so that the precision of the output current of the constant current source chip U1 is improved.

[0009] Preferably, the model of the constant current source chip U1 is LM234Z-6 / NOPB.

[0010] Preferably, the LCD module further comprises a first resistor R1, one end of the first resistor R1 is connected with the negative electrode of the thermistor, and the other end is connected with the GND end of the constant current source module, and the resistance value of the first resistor R1 is 0 ohm, so that the thermistor is in a complete current loop.

[0011] Preferably, the LCD module temperature detection device further comprises a protection assembly arranged on one side of the sampling end of the ADC module, and the protection assembly comprises a second resistor R2 and a first diode D1, the second resistor R2 is connected in series with the ADC module, the anode of the first diode D1 is connected to a node on the side of the second resistor R2 away from the ADC module, and the cathode is connected with a 3V power supply.

[0012] Preferably, the main control module further comprises a current sampling module composed of a current sampling resistor and a differential operational amplifier, so that the voltage difference sampled by the current sampling module is output to the ADC module, and the main control module can obtain the current data of the output current of the constant current source chip U1 in real time through operation.

[0013] Preferably, the host computer module is connected with the main control module through a gigabit network port or a serial port to transmit data, and the host computer module is composed of a computer host, a display and host computer software, and is used for processing the data received from the main control module.

[0014] Compared with the prior art, the LCD module temperature detection device has the following advantages:

[0015] The constant current source module outputs current Iset and the ADC module in the main control module detects the Vntc voltage, and then the resistance of the thermistor in the backlight module of the LCD module is measured, the change of the detected resistance is used to judge the change of the temperature of the LCD module, so that the temperature detection is not affected by the power supply ripple, temperature drift, voltage and current sampling precision error and other factors, and the detection device with the constant current source as the main body is more simplified compared with the constant voltage source module circuit, and the cost can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a structure block diagram of an embodiment of the LCD module temperature detection device of the utility model;

[0017] Figure 2 It is a circuit diagram of an embodiment of the LCD module temperature detection device of the utility model. DETAILED DESCRIPTION

[0018] The preferred embodiments of the utility model are described in detail below in combination with the drawings, so that the advantages and characteristics of the utility model can be more easily understood by those skilled in the art, and the protection scope of the utility model can be more clearly and explicitly defined.

[0019] REFERENCE Figure 1 AND Figure 2 , Figure 1 It is a structure block diagram of an LCD module temperature detection device provided by the embodiment of the utility model; Figure 2 It is a circuit diagram of an LCD module temperature detection device provided by the embodiment of the utility model.

[0020] As Figure 1 AND Figure 2 shown, the technical scheme of the utility model is an LCD module temperature detection device, the LCD module includes a backlight module, the backlight module includes a thermistor, and the LCD module includes an upper computer module, a main control module, a constant current source module and the LCD module.

[0021] The application provides an LCD module temperature detection device. The voltage Vntc at the output end of a constant current source module is collected by an ADC module in a master control module. The master control module calculates Rntc=Vntc / Iset (Iset is the current value fixedly output by the constant current source module, and Rntc is the resistance value of the thermistor), and then converts corresponding temperature data according to a temperature and resistance value conversion table of the corresponding type of thermistor. The collected voltage Vntc, calculated Rntc and temperature data are uploaded to the host computer module. The host computer module further processes the received temperature data, for example, makes an alarm protection or reduces the product brightness when the temperature is too high, so as to reduce the temperature. Further, the master control module can be an MCU or ARM integrated with an ADC module, or a module composed of an FPGA and an independent ADC chip.

[0022] In some embodiments, reference is made to Figure 1 and Figure 2 The constant current source module comprises a constant current source chip U1 and a first capacitor C1. The constant current source chip U1 comprises three pins. The first pin is connected with a power supply end VCC, and the third pin is connected with the positive end of the thermistor. One end of the first capacitor C1 is connected with a node between the first pin and the power supply end VCC, and the other end is grounded. VCC is a 5V power supply.

[0023] Further, the constant current source module further comprises a setting resistor Rset. The two ends of the setting resistor Rset are connected with the second pin and the third pin of the constant current source chip U1, respectively, for adjusting the output current of the constant current source chip U1 by adjusting the resistance value of the setting resistor Rset.

[0024] Exemplarily, the constant current source module is powered by the power supply end VCC. Iset is fixedly set according to the characteristics of the thermistor to ensure that Vntc does not exceed 3V in the working environment within the specification, that is, the range of the integrated ADC module.

[0025] In some embodiments, the setting resistor Rset is a resistance with a precision of one thousandth, for improving the precision of the output current of the constant current source chip U1.

[0026] In some embodiments, the model of the constant current source chip U1 is LM234Z-6 / NOPB.

[0027] Exemplarily, the constant current source chip U1 outputs a current Iset = 67.7 mV / Rset, wherein 67.7 mV is a reference voltage value of the constant current source chip LM234Z-6 / NOPB at 25°C for determining a set current (ISET). Specifically, in the present embodiment, the thermistor is of the model NCP18XM332, but the type of the thermistor in the present solution is only a reference model, and different models of LCD module products will match different models of thermistors. See Table 1 for a partial thermistor value and temperature value table of the thermistor NCP18XM332:

[0028] Table 1: Thermistor value and temperature value table

[0029]

[0030] Only two different resistance values and different B values of the thermistor of the same model NCP18XM332 are shown in the table, and the resistance value information corresponding to -40°C to 40°C. According to the thermistor temperature and resistance value table of the corresponding model, the corresponding temperature data can be converted.

[0031] In some embodiments, with reference to Figure 1 and Figure 2 , the LCD module further includes a first resistor R1, one end of the first resistor R1 being connected to the negative end of the thermistor, and the other end being connected to the GND end of the constant current source module. The resistance value of the first resistor R1 is 0 ohm, which is used to make the thermistor in a complete current loop.

[0032] In some embodiments, with reference to Figure 1 and Figure 2 , the LCD module temperature detection device further includes a protection assembly, which is arranged on one side of the sampling end of the ADC module and includes a second resistor R2 and a first diode D1. The second resistor R2 is connected in series with the ADC module, the positive end of the first diode D1 is connected to a node on the side of the second resistor R2 away from the ADC module, and the negative end is connected to a 3V power supply.

[0033] Exemplarily, the second resistor R2 and the first diode D1 are in the middle of the sampling network of the ADC module. Specifically, in the present embodiment, the resistance value of the second resistor R2 is 100KΩ, which is set to a relatively high resistance value for current limiting. At the same time, the first diode D1 acts as a clamping diode, which cooperates with the second resistor R2 to protect the ADC module from being damaged and avoid damage to the ADC module caused by an abnormally large voltage output by Vntc.

[0034] In some embodiments, with reference to Figure 1 and Figure 2The master control module further comprises a current sampling module composed of a current sampling resistor and a differential operational amplifier, which is used to output the sampled pressure difference to the ADC module through the current sampling module, so that the master control module can obtain the current data of the output current of the constant current source chip U1 in real time through operation.

[0035] Exemplarily, the current sampling module is arranged to further improve the measurement accuracy of Iset, and the current value of Iset can be monitored in real time.

[0036] In some embodiments, the host computer module is connected with the master control module through a gigabit network port or a serial port to transmit data.

[0037] Exemplarily, the host computer module is connected with the master control module to realize bidirectional transmission of data, and receives data such as resistance value, voltage, current and temperature of the thermistor.

[0038] The above embodiments are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application shall be covered within the protection scope of the present application.

Claims

1. An LCD module temperature detecting apparatus, the LCD module comprising a backlight module, the backlight module comprising a thermistor, characterized by, The application relates to a constant current source module, which comprises an upper computer module, a main control module, a constant current source module and an LCD module.

2. The LCD module temperature detection apparatus according to claim 1, wherein The constant current source module comprises a constant current source chip U1 and a first capacitor C1; the constant current source chip U1 comprises three pins, the first pin is connected with a power supply end VCC, and the third pin is connected with the positive pole end of a thermistor; one end of the first capacitor C1 is connected with a node between the first pin and the power supply end VCC, and the other end is grounded; and the VCC is a 5V power supply.

3. The LCD module temperature detection apparatus according to claim 2, wherein The constant current source module further comprises a setting resistor Rset, two ends of the setting resistor Rset are connected with the second pin and the third pin of the constant current source chip U1 respectively, and the output current of the constant current source chip U1 is adjusted by adjusting the resistance value of the setting resistor Rset.

4. The LCD module temperature detection apparatus according to claim 3, wherein The setting resistor Rset is a resistor with a precision of one thousandth, which is used for improving the precision of the output current of the constant current source chip U1.

5. The LCD module temperature detection apparatus according to claim 2, wherein The model of the constant current source chip U1 is LM234Z-6 / NOPB.

6. The LCD module temperature detection apparatus of claim 1, wherein The LCD module further comprises a first resistor R1, one end of the first resistor R1 is connected with the negative pole end of the thermistor, and the other end is connected with the GND end of the constant current source module; the resistance value of the first resistor R1 is 0 ohm, which is used for making the thermistor in a complete current loop.

7. The LCD module temperature detection apparatus of claim 1, wherein The protection assembly is arranged on one side of the sampling end of the ADC module and comprises a second resistor R2 and a first diode D1; the second resistor R2 is connected with the ADC module in series; the positive pole end of the first diode D1 is connected with a node on the side, away from the ADC module, of the second resistor R2, and the negative pole end is connected with a 3V power supply.

8. The LCD module temperature detection apparatus of claim 2, wherein The main control module further comprises a current sampling module, which is composed of a current sampling resistor and a differential operational amplifier, and is used for outputting the sampled pressure difference to the ADC module, so that the main control module can obtain the current data of the output current of the constant current source chip U1 in real time through operation.

9. The LCD module temperature detection apparatus of claim 1, wherein The upper computer module is connected with the main control module through a gigabit network port or a serial port to transmit data; the upper computer module is composed of a computer host, a display and upper computer software, and is used for processing the data received from the main control module.

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