LED backlight adjustment control system

Abstract

The utility model discloses an LED backlight adjusting control system which comprises a mainboard ADJ input module, a photoresistor input module, a manual potentiometer input module, an analog signal switching module, an analog signal to PWM module and a PWM output module. A mainboard dimming analog signal of the mainboard ADJ input module is input to the PWM output module; the analog signal switching module selects the photoresistor input module or the manual potentiometer input module as an input signal and outputs the input signal; the analog signal-to-PWM module receives an output signal of the analog signal switching module, converts the output signal into a 5V-PWM signal and outputs the 5V-PWM signal to the PWM output module; and the PWM output module receives the mainboard dimming analog signal of the mainboard ADJ input module and outputs a dimming signal for controlling the LED power supply, or receives a 5V-PWM signal of the analog signal-to-PWM module, converts the 5V-PWM signal into a 10V-PWM signal and outputs the 10V-PWM signal to the LED power supply dimming signal. According to the utility model, three backlight adjusting input modes are supported, different dimming modes can be selected, 5V-PWM signals can be converted into 10V-PWM signals at the same time, and market requirements are met.

Description

Technical Field

[0001] The utility model relates to a backlight adjustment circuit of a display device, in particular to an LED backlight adjustment control system. Background Art

[0002] The full outdoor high brightness LCD display has a brightness of up to 3000cd / m 2 In actual use, in order to reduce power consumption and extend service life, reduce heat generation without affecting the viewing effect, it is necessary to dynamically adjust the LCD screen backlight brightness according to the ambient optical brightness.

[0003] The existing methods for adjusting LED backlight are single and fixed, either PWM, ADJ, or only mainboard adjustment, only one of the three. In addition, most of the existing methods for adjusting LED backlight can only support 0-5V, while most waterproof LED power supplies on the market require 0-10v adjustment, lacking the corresponding backlight adjustment method. Summary of the invention

[0004] In view of the above existing technical problems, the utility model provides an LED backlight adjustment control system, which has multiple backlight adjustment input modes and supports 0-10V adjustment output.

[0005] In order to solve the above technical problems, the utility model adopts the following technical solutions: an LED backlight adjustment control system, comprising a mainboard ADJ input module, a photoresistor input module, a manual potentiometer input module, an analog signal switching module, an analog signal to PWM module and a PWM output module; the mainboard ADJ input module is connected to the PWM output module, and the mainboard dimming analog signal of the mainboard ADJ input module is input to the PWM output module; the photoresistor input module and the manual potentiometer input module are connected to the input end of the analog signal switching module; the analog signal switching module selects the photoresistor input module or the manual potentiometer input module as the input signal and outputs it, and the output end of the analog signal switching module is connected to the analog signal to PWM module; the analog signal to PWM module is connected to the PWM output module, and the analog signal to PWM module receives the output signal of the analog signal switching module, converts it into a 5V-PWM signal and outputs it to the PWM output module; the PWM output module receives the mainboard dimming analog signal of the mainboard ADJ input module and outputs it to the LED power dimming signal, or receives the 5V-PWM signal of the analog signal to PWM module, and converts it into a 10V-PWM signal and outputs the control LED power dimming signal.

[0006] The utility model further comprises: the analog signal switching module is an analog channel switching chip U5, and the analog signal to PWM module is an analog signal to PWM chip U3; the A2 pin 3 of the analog channel switching chip U5 is connected to the manual potentiometer input module, the A1 pin 1 of the analog channel switching chip U5 is connected to the photoresistor input module, the EN pin 6 of the analog channel switching chip U5 selects the input of the photoresistor input module and the manual potentiometer input module, and the NC pin 4 of the analog channel switching chip U5 is connected to the VIN pin 3 of the analog signal to PWM chip U3 through a resistor R11; the VIN pin 3 of the analog signal to PWM chip U3 inputs an analog signal, the pin 6 of the chip U3 outputs a 5V PWM signal, and the pin 7 of the chip U3 is a reverse PWM signal.

[0007] The utility model further comprises a mainboard ADJ input module including a connector U7, and a step-down module is connected in parallel to the mainboard ADJ input module, and the step-down module includes a connector U6; the connector U7 and the connector U6 are connected in parallel to 12V and GND as circuit power input, and are stabilized to 5V voltage through an anti-reverse protection diode FS and a fuse AMS-117; the ON / OFF pins of the connector U7 and the connector U6 are connected to the PWM output module as the output enable control pin of the comparator; the ADJ pin 3 of the connector U7 is input to the PWM output module through resistors R5 and R18 as a mainboard dimming analog signal.

[0008] The utility model further comprises a photoresistor input module which includes a photoresistor, which is respectively connected to resistor R14 and resistor R6 to set a bias voltage, and the photoresistor is connected to an analog signal switching module via resistor R17, resistor R9, resistor R8, transistor Q1 and resistor R3; when the resistance value of the photoresistor changes, it is input to the transistor Q1 amplification and inversion circuit in sequence via resistor R17, resistor R9 and resistor R8, and then input to the A1 pin of the analog switching analog channel switching chip U5 via resistor R3.

[0009] In the present invention, the photoresistor is further connected to a resistor R13, a capacitor C6 and a capacitor C7 via a resistor R17; and the transistor Q1 is connected to a resistor R15 to form a bias circuit.

[0010] The utility model further comprises a manual potentiometer input module comprising a connector U1, a pin R-5V of the connector U1 being connected to an EN pin of a U5 chip via resistors R7 and R12, a pin RM being connected to an A2 pin of the chip U5, and a pin R-GED being a potentiometer switch pin.

[0011] The utility model further comprises a LM358-A comparator and a LM358-B comparator, wherein the LM358-A comparator receives a 5V-PWM signal from the analog signal to PWM module, and converts the signal into a 10V-PWM signal, which is output in three ways to J1, J2 and J4 to control the dimming signals of the three LED power supplies; pin 6 of the LM358-B comparator is connected to the ON / OFF pin of the ADJ input module of the mainboard, and pin 7 of the LM358-B comparator is connected to the LM358-A comparator, and when the ON / OFF enable signal of the LM358-B comparator is 5V, pin 7 outputs a low level, and the LM358-A depends on the input status of pin 3, and when ON / OFF is a low level of 0V, the 10vPWM output is 0V off output.

[0012] Furthermore, in the present invention, pin 1 of the LM358-A comparator is connected with a buck diode U12 and a buck diode U13.

[0013] The utility model further provides a light board groove on the front side of the shell, a wiring hole on the light board groove is connected with the inner side of the shell, and the light board is installed in the light board groove.

[0014] The beneficial effects of adopting the above technical solution are: the utility model integrates a mainboard ADJ input module, a photoresistor input module, and a manual potentiometer input module, and can support three backlight adjustment input methods, and can select different dimming modes to adjust the LED backlight, so that the display device can flexibly switch the dimming mode. At the same time, an analog signal to PWM module is provided, which can convert 5V-PWM into 10V-PWM signal, meeting the market demand for 0-10v adjustment of waterproof LED power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a principle block diagram of the utility model;

[0016] Figure 2 This is a circuit diagram of the analog signal switching module and the analog signal to PWM module of the utility model;

[0017] Figure 3 This is the circuit diagram of the ADJ input module of the mainboard of the utility model;

[0018] Figure 4 This is a circuit diagram of the voltage-reducing module of the utility model;

[0019] Figure 5 This is a circuit diagram of the photoresistor input module of the utility model;

[0020] Figure 6 This is the circuit diagram of the manual potentiometer input module of the utility model;

[0021] Figure 7 This is a circuit diagram of the PWM output module of the utility model; DETAILED DESCRIPTION

[0022] The utility model is further described in detail below in conjunction with the accompanying drawings.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] An embodiment of the present utility model: Figure 1 As shown, an LED backlight adjustment control system includes a mainboard ADJ input module, a photoresistor input module, a manual potentiometer input module, an analog signal switching module, an analog signal conversion PWM module and a PWM output module; the mainboard ADJ input module is connected to the PWM output module, and the mainboard dimming analog signal of the mainboard ADJ input module is input to the PWM output module; the photoresistor input module and the manual potentiometer input module are connected to the input end of the analog signal switching module; the analog signal switching module selects the photoresistor input module or the manual potentiometer input module as the input signal and outputs it, and the output end of the analog signal switching module is connected to the analog signal conversion PWM module; the analog signal conversion PWM module is connected to the PWM output module, and the analog signal conversion PWM module receives the output signal of the analog signal switching module, converts it into a 5V-PWM signal and outputs it to the PWM output module; the PWM output module receives the mainboard dimming analog signal of the mainboard ADJ input module and outputs it to the LED power dimming signal, or receives the 5V-PWM signal of the analog signal conversion PWM module, and converts it into a 10V-PWM signal to output and control the LED power dimming signal. The utility model integrates a mainboard ADJ input module, a photoresistor input module, and a manual potentiometer input module, and can support three backlight adjustment input methods. Different dimming modes can be selected to adjust the LED backlight, so that the display device can flexibly switch the dimming mode. At the same time, an analog signal to PWM module is provided, which can convert 5V-PWM into 10V-PWM signal, meeting the market demand for 0-10v adjustment of waterproof LED power supply.

[0025] In other specific embodiments of the present invention, the rest is the same as the above embodiments, except that: Figure 2As shown, the analog signal switching module is the analog channel switching chip U5, and the analog signal to PWM module is the analog signal to PWM chip U3; the A2 pin 3 of the analog channel switching chip U5 is connected to the manual potentiometer input module, the A1 pin 1 of the analog channel switching chip U5 is connected to the photoresistor input module, the EN pin 6 of the analog channel switching chip U5 selects the photoresistor input module and the manual potentiometer input module as input, and the NC pin 4 of the analog channel switching chip U5 is connected to the VIN pin 3 of the analog signal to PWM chip U3 through a resistor R11; the VIN pin 3 of the analog signal to PWM chip U3 inputs an analog signal, the pin 6 of the chip U3 outputs a 5V PWM signal, and the pin 7 of the chip U3 is a reverse PWM signal.

[0026] In other specific embodiments of the present invention, the rest is the same as the above embodiments, except that: Figure 3 and Figure 4 As shown, the mainboard ADJ input module includes a connector U7, and the mainboard ADJ input module is connected in parallel with a buck module, and the buck module includes a connector U6; the connector U7 and the connector U6 are connected in parallel to 12V and GND as the circuit power input, and the voltage is stabilized to 5V through the anti-reverse protection diode FS and the fuse AMS-117 for use by the subsequent circuit. The ON / OFF pins of the connector U7 and the connector U6 are connected to the PWM output module as the output enable control pin of the comparator; the ADJ pin 3 of the connector U7 is used as the mainboard dimming analog signal and input to the comparator LM358 of the PWM output module through the resistor R5 and the resistor R18.

[0027] In other specific embodiments of the present invention, the rest is the same as the above embodiments, except that: Figure 5 As shown, the photoresistor input module includes a photoresistor, which is respectively connected to resistor R14 and resistor R6 to set a bias voltage, and the photoresistor is connected to the analog signal switching module through resistor R17, resistor R9, resistor R8, transistor Q1 and resistor R3; when the resistance value of the photoresistor changes, it is input to the transistor Q1 amplification and inversion circuit through resistor R17, resistor R9 and resistor R8 in sequence, and then input to the A1 pin of the analog switching analog channel switching chip U5 through resistor R3.

[0028] In other specific embodiments of the present invention, the rest is the same as the above embodiments, except that: Figure 5As shown, the photoresistor is also connected to resistor R13, capacitor C6 and capacitor C7 through resistor R17; the transistor Q1 is connected to resistor R15 as a bias circuit. Resistor R13 and capacitor C6 are delay subcircuits to control the change speed of the photoresistor, and C7 is used to interfere with the bypass capacitor. U9 and U8 are the lowest bias voltages, and no output changes when the voltage is lower than 1.2V. Resistor R15 is a bias circuit for transistor Q1.

[0029] In other specific embodiments of the present invention, the rest is the same as the above embodiments, except that: Figure 6 As shown, the manual potentiometer input module includes a connector U1, the pin R-5V of the connector U1 is connected to the EN pin of the U5 chip through resistors R7 and R12, the pin RM is connected to the A2 pin of the chip U5, and the pin R-GED is the potentiometer switch pin. The RM pin transmits the potentiometer change voltage to the analog switching chip U5, EN is used as the analog switching chip selection signal, and the resistors R7 and R12 are pull-up bias resistors.

[0030] In other specific embodiments of the present invention, the rest is the same as the above embodiments, except that: Figure 7 As shown, the PWM output module includes an LM358-A comparator and an LM358-B comparator. The LM358-A comparator receives the 5V-PWM signal of the analog signal to PWM module, and converts it into a 10V-PWM signal and outputs it in three ways to J1, J2, and J4 to control the dimming signals of the 3 LED power supplies. Pin 6 of the LM358-B comparator is connected to the ON / OFF pin of the mainboard ADJ input module, and pin 7 of the LM358-B comparator is connected to the LM358-A comparator. When the ON / OFF enable signal of the LM358-B comparator is 5v, pin 7 outputs a low level. The LM358-A depends on the input status of pin 3. When ON / OFF is a low level of 0v, the 10vPWM output is 0V to turn off the output. Resistors R16 and R19 are LM358-B voltage bias resistors, and resistors R4 and 3 are LM358-A voltage bias resistors.

[0031] In other specific embodiments of the present invention, the rest is the same as the above embodiments, except that: Figure 7 As shown, pin 1 of the LM358-A comparator is connected with a buck diode U12 and a buck diode U13, and the buck diode converts 12V to 10V.

[0032] Of course, the above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with this technology to understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit of the main technical solution of the utility model should be included in the protection scope of the utility model.

Claims

1. An LED backlight adjustment control system, characterized in that: Including mainboard ADJ input module, photoresistor input module, manual potentiometer input module, analog signal switching module, analog signal to PWM module and PWM output module; The mainboard ADJ input module is connected to the PWM output module, and the mainboard dimming analog signal of the mainboard ADJ input module is input to the PWM output module; The photoresistor input module and the manual potentiometer input module are connected to the input end of the analog signal switching module; The analog signal switching module selects the photoresistor input module or the manual potentiometer input module as the input signal and outputs it, and the output end of the analog signal switching module is connected to the analog signal conversion PWM module; The analog signal to PWM module is connected to the PWM output module, and the analog signal to PWM module receives the output signal of the analog signal switching module, converts it into a 5V-PWM signal and outputs it to the PWM output module; The PWM output module receives the mainboard dimming analog signal from the mainboard ADJ input module and outputs it to the LED power dimming signal, or receives the 5V-PWM signal from the analog signal to PWM module and converts it into a 10V-PWM signal to output and control the LED power dimming signal.

2. The LED backlight adjustment control system according to claim 1, characterized in that: The analog signal switching module is an analog channel switching chip U5, and the analog signal to PWM module is an analog signal to PWM chip U3; the A2 pin 3 of the analog channel switching chip U5 is connected to the manual potentiometer input module, the A1 pin 1 of the analog channel switching chip U5 is connected to the photoresistor input module, the EN pin 6 of the analog channel switching chip U5 selects the input signals of the photoresistor input module and the manual potentiometer input module for use, and the NC pin 4 of the analog channel switching chip U5 is connected to the VIN pin 3 of the analog signal to PWM chip U3 through a resistor R11; the VIN pin 3 of the analog signal to PWM chip U3 inputs an analog signal, the pin 6 of the chip U3 outputs a 5V PWM signal, and the pin 7 of the chip U3 is a reverse PWM signal.

3. The LED backlight adjustment control system according to claim 2, characterized in that: The mainboard ADJ input module includes a connector U7, and the mainboard ADJ input module is connected in parallel with a step-down module, and the step-down module includes a connector U6; the connector U7 and the connector U6 are connected in parallel to 12V and GND as circuit power input, and are stabilized to 5V voltage through the anti-reverse protection diode FS and the fuse AMS-117; the ON / OFF pins of the connector U7 and the connector U6 are connected to the PWM output module as the output enable control pin of the comparator; the ADJ pin 3 of the connector U7 is input to the PWM output module through the resistor R5 and the resistor R18 as the mainboard dimming analog signal.

4. The LED backlight adjustment control system according to claim 2, characterized in that: The photoresistor input module includes a photoresistor, which is respectively connected to a resistor R14 and a resistor R6 to set a bias voltage, and the photoresistor is connected to an analog signal switching module through a resistor R17, a resistor R9, a resistor R8, a transistor Q1 and a resistor R3; when the resistance value of the photoresistor changes, it is input to the transistor Q1 amplification and inversion circuit through the resistor R17, the resistor R9 and the resistor R8 in sequence, and then input to the A1 pin of the analog switching analog channel switching chip U5 through the resistor R3.

5. The LED backlight adjustment control system according to claim 4, characterized in that: The photoresistor is also connected to a resistor R13, a capacitor C6 and a capacitor C7 via a resistor R17; and the transistor Q1 is connected to a resistor R15 to form a bias circuit.

6. The LED backlight adjustment control system according to claim 2, characterized in that: The manual potentiometer input module includes a connector U1, a pin R-5V of the connector U1 is connected to the EN pin of the U5 chip through resistors R7 and R12, a pin RM is connected to the A2 pin of the chip U5, and a pin R-GED is a potentiometer switch pin.

7. The LED backlight adjustment control system according to claim 3, characterized in that: The PWM output module includes an LM358-A comparator and an LM358-B comparator. The LM358-A comparator receives the 5V-PWM signal of the analog signal to PWM module, and converts it into a 10V-PWM signal and outputs it in three ways to J1, J2, and J4 to control the dimming signals of the 3 LED power supplies; Pin 6 of the LM358-B comparator is connected to the ON / OFF pin of the mainboard ADJ input module, and Pin 7 of the LM358-B comparator is connected to the LM358-A comparator. When the ON / OFF enable signal of the LM358-B comparator is 5v, the 7th pin outputs a low level, and the LM358-A depends on the input status of the 3rd pin. When ON / OFF is a low level of 0v, the 10vPWM output is 0V to turn off the output.

8. The LED backlight adjustment control system according to claim 7, characterized in that: Pin 1 of the LM358-A comparator is connected with a buck diode U12 and a buck diode U13.

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