CN215988075U

CN215988075U - Domestic constant-current backlight plate

Info

Publication number: CN215988075U
Application number: CN202122110459.5U
Authority: CN
Inventors: 吴小华; 周传煌; 江从茂
Original assignee: Wuhan Huazhiyang Technology Co ltd
Current assignee: Wuhan Huazhiyang Technology Co ltd
Priority date: 2021-09-02
Filing date: 2021-09-02
Publication date: 2022-03-08
Anticipated expiration: 2031-09-02

Abstract

The utility model discloses a domestic constant current backlight board, which relates to the field of liquid crystal backlight circuits and comprises: the backlight control device comprises a power supply assembly, a DC-DC conversion unit, a backlight control unit, a backlight driving unit, a backlight abnormal reset unit and a defogging unit, wherein the power supply assembly is electrically connected with the DC-DC conversion unit, the backlight control unit and the defogging unit are both electrically connected with a power output end of the DC-DC conversion unit, the defogging unit is electrically connected with the power supply assembly, the backlight driving unit is electrically connected with a liquid crystal driving assembly, the backlight control unit is electrically connected with the backlight driving unit, and the backlight abnormal reset unit is electrically connected with the backlight control unit. The utility model has the advantages that: the backlight main control chip optimizes the feedback function by the feedback function, and subtracts a circuit for design feedback acquisition, so that the circuit area is reduced, the miniaturization design and EMC design of the system are facilitated, the backlight abnormal reset function and the defogging function are added, and the normal operation capability of the backlight plate in the environment with the temperature and humidity and easy dewing is improved.

Description

Domestic constant-current backlight plate

Technical Field

The utility model relates to the field of liquid crystal backlight circuits, in particular to a domestic constant-current backlight plate.

Background

Light-emitting diodes, abbreviated as LEDs in english, are light-emitting diodes, and are widely used in the fields of illumination, lamp decoration, and backlight lamps of liquid crystal displays. In the field of liquid crystal screen backlight lamps, the color-changeable liquid crystal display panel can be used as a green, red, blue and white backlight source, can also be used as a color-changeable backlight source, and is the mainstream method for the backlight source of various liquid crystal displays at home and abroad at present. Compared with a Cold Cathode Fluorescent Lamp (CCFL), the LED has the advantages of energy conservation, long service life, high safety level, stable performance, support of various dimming modes and the like in the aspect of backlight source use.

The LED driving circuit mainly comprises a PWM or analog dimming interface, a power interface and a backlight output interface. The common driving method in the field is that the backlight is adjusted in a fixed voltage mode, so that for displays of different models and sizes, corresponding hardware circuits need to be modified to adapt to the voltage requirements of the displays, and the same model circuit cannot be used for simultaneously adapting to various liquid crystal displays; the common liquid crystal display cannot automatically recover due to screen blackness caused by abnormal backlight; because the display surface is fogged under the dew condensation environment, resulting in a display blurring phenomenon.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problems, the technical scheme provides a domestic constant-current backlight plate, and solves the problem that the common driving method proposed in the background technology is that the backlight is regulated in a fixed voltage mode, so that for displays of different models and sizes, corresponding hardware circuits need to be modified to adapt to the voltage requirements of the displays, and the purpose that circuits of the same model can not be simultaneously adapted to various liquid crystal displays can not be achieved; the common liquid crystal display cannot automatically recover due to screen blackness caused by abnormal backlight; because the display surface fogging causes a problem of display blurring in the dew condensation environment.

In order to achieve the above purposes, the technical scheme adopted by the utility model is as follows:

a domestic constant-current backlight plate comprises: the backlight control device comprises a power supply assembly, a DC-DC conversion unit, a backlight control unit, a backlight driving unit, a backlight abnormal reset unit and a defogging unit, wherein the power supply assembly is electrically connected with the DC-DC conversion unit, the backlight control unit and the defogging unit are both electrically connected with the power output end of the DC-DC conversion unit, the defogging unit is electrically connected with the power supply assembly, the backlight driving unit is electrically connected with the liquid crystal driving assembly, the backlight control unit is electrically connected with the backlight driving unit, the backlight driving unit receives PWM brightness and enabling signals transmitted by the backlight control unit and the liquid crystal driving assembly and outputs backlight signals, backlight brightness is regulated and controlled, the backlight abnormal reset unit is electrically connected with the backlight control unit, and the backlight abnormal reset unit collects backlight signal voltage.

Preferably, a defogging panel is integrated in the backlight control unit, the defogging panel is electrically connected with the defogging key, the defogging unit is electrically connected with the defogging panel, and the defogging panel is used for receiving an instruction of the defogging key, generating a defogging signal according to the instruction and transmitting the defogging signal to the defogging unit.

Preferably, the DC-DC conversion unit adopts a HYM2596T-5.0 low-voltage direct-current power supply and an SSP1117-3.3 low-voltage linear power supply, a DC24V power supply is input from a power supply assembly, and is converted by the HYM2596T-5.0 to output DC5V, the DC5V is converted by the SSP1117-3.3 to DC3.3V to provide power for the backlight control unit, and the DC5V simultaneously provides a 5V enable signal for the defogging unit.

Preferably, the backlight driving unit is composed of a Boost type LED driving control chip XC84624, a JGB200G06A model MOS transistor, an SWPA8050S220MT inductor, and a peripheral circuit, and converts the collected backlight enable signal and PWM signal of the liquid crystal driving assembly into the magnitude of current of the LED backlight to be output, thereby changing the brightness of the liquid crystal display.

Preferably, the main chip of the backlight control unit is mainly a GD32F103C8T6 single chip microcomputer.

Preferably, the main chip of the backlight abnormity reset unit adopts SGMOP17 as a comparison output and is driven by DC3.3V power supply.

Preferably, the defogging unit is driven by a current through a JGB200G06A model MOS transistor, is controlled by a UPC817 opto-coupler, is switched by a power module to output DC24V as a MOS transistor drive DS pole drive power supply, and is output DC5V as a row MOS transistor drive GS pole bias voltage through a DC-DC conversion unit.

Compared with the prior art, the utility model has the advantages that:

1) the utility model simplifies the backlight driving scheme of the liquid crystal display, the backlight main control chip optimizes the feedback function due to the feedback function, and subtracts the circuit for designing feedback acquisition, thereby reducing the circuit area, being beneficial to the miniaturization design and EMC design of the system, and the circuit can be suitable for the backlight driving of liquid crystal panels with various models and sizes without modifying hardware.

2) The backlight abnormity reset unit is arranged to collect backlight signal voltage and compare the backlight signal voltage with a standard signal voltage value, and when the backlight signal voltage is abnormal, the backlight abnormity reset unit can quickly respond to the abnormal backlight signal voltage value to reset the abnormal backlight;

3) according to the utility model, the defogging unit is arranged, and the defogging unit can be controlled by the defogging key to defogge the display in a dewing environment, so that the liquid crystal display can normally operate in an environment with high temperature and humidity and easy dewing.

Drawings

FIG. 1 is a block diagram of the system of the present invention;

fig. 2 is a circuit diagram of a DC-DC conversion unit in the present invention;

FIG. 3 is a circuit diagram of a backlight driving unit according to the present invention;

FIG. 4 is a circuit diagram of a backlight control unit according to the present invention;

FIG. 5 is a circuit diagram of a backlight abnormal reset unit according to the present invention;

FIG. 6 is a circuit diagram of a defogging unit according to the present invention.

Detailed Description

The following description is presented to disclose the utility model so as to enable any person skilled in the art to practice the utility model. The preferred embodiments in the following description are given by way of example only, and other obvious variations will occur to those skilled in the art.

Referring to fig. 1, a domestic constant current backlight plate includes: the backlight control device comprises a power supply assembly, a DC-DC conversion unit, a backlight control unit, a backlight drive unit, a backlight abnormal reset unit and a defogging unit, wherein the power supply assembly is electrically connected with the DC-DC conversion unit, the backlight control unit and the defogging unit are both electrically connected with the power output end of the DC-DC conversion unit, the defogging unit is electrically connected with the power supply assembly, the backlight drive unit is electrically connected with the liquid crystal drive assembly, the backlight control unit is electrically connected with the backlight drive unit, the backlight drive unit receives PWM brightness and enabling signals transmitted by the backlight control unit and the liquid crystal drive assembly and outputs backlight signals to regulate and control the backlight brightness, the backlight abnormal reset unit is electrically connected with the backlight control unit, the backlight abnormal reset unit collects backlight signal voltage, and a defogging panel is integrated in the backlight control unit, the demisting device comprises a demisting panel, a demisting unit and a demisting panel, wherein the demisting panel is electrically connected with the demisting key, the demisting unit is electrically connected with the demisting panel, and the demisting panel is used for receiving an instruction of the demisting key, generating a demisting signal according to the instruction and transmitting the demisting signal to the demisting unit.

Referring to fig. 2, the DC-DC conversion unit adopts a HYM2596T-5.0 power supply and a maximum current of 3A, PIN1 and PIN21 of a power supply interface P9 are connected to an SS510 diode and then externally connected with a 470uF electrolytic capacitor to be input to an IN terminal of the HYM2596T-5.0, ON/OFF, GND _ PAD and GND are grounded, an OUT terminal is externally connected with a reverse schottky diode SK33 to perform overvoltage protection, and the output DC5V is filtered by a 33uH inductor and then passes through a 220uF electrolytic capacitor. The DC5V is connected to the VIN terminal of SSP1117-3.3 through the chip capacitor of 10uF, and the Vout terminal of SSP1117-3.3 is filtered by the chip capacitors of 10uF and 0.1uF, and then is output DC3.3V.

Referring to fig. 3, the backlight driving unit uses XC84624 chip, GATE pin outputs driving signal, 33uH inductor, MOS transistor and SS510 together drive output voltage, and outputs stable Vout after being filtered by 4 2.2uF ceramic capacitors and a 100uF electrolytic capacitor; the duty ratio or analog quantity of the PWM _ IN is changed to directly change the driving current and adjust the brightness of the liquid crystal screen; the method comprises the steps that a BackLight _ EN _ IN of a liquid crystal driving assembly and an LED _ EN signal of a BackLight control unit output an ENABLE signal to an ENABLE end of XC4624 after being subjected to AND operation through CX1G708 STNI; the CADIM end of XC4624 is externally connected with a 1uF capacitor and a 51K resistor in parallel, so that XC84624 can meet the requirement of analog dimming capability; the RT end external resistor of XC84624 can effectively change the driving frequency of the GATE pin; the LED receiving ends of XC84624 are all short-circuited (P13 terminal), so that the driving requirement of more than 4 groups of LEDs is met, and the current of each path of LEDs is consistent.

Referring to fig. 4, the backlight control unit uses a GD32F103C8T6 single chip microcomputer, the check is a backlight recovery unit feedback signal, when the signal has a rising edge and the high level is greater than 100us, the single chip microcomputer outputs the LED _ EN low level for 100ms and then outputs the LED _ EN high level, and the backlight driving unit resets. QW3.3V and QW0V are input signals of the defogging optocoupler, KEY _ QW is a defogging KEY signal, when the signal is received to be high, QW3.3V and QW0V output 3.3V and 0V respectively, defogging is started, after recording for 5-20 minutes, QW3.3V and QW0V output 0V, and defogging is finished; JTAG _ SWD and JTAG _ SWC are download ports.

Referring to fig. 5, the backlight abnormal reset unit uses an SGMOP17C chip, and the divided backlight output voltage Vout enters the negative terminal of the chip for input, and the divided voltage of 5V enters the positive terminal of the chip for input. When Vout is less than 25V, the Check is high, and the backlight driving unit is reset.

Referring to fig. 6, the defogging unit is driven by current using a JGB200G06A model MOS transistor, and is controlled to be switched by a UPC817 opto-coupler, and the UPC817 open-light output end is controlled by a single chip, and the circuit can heat the 19 inch wave shield heating panel from 25 ℃ to 43 ℃ within 10 minutes.

In summary, the utility model has the advantages that: the backlight main control chip optimizes the feedback function by the feedback function, and subtracts a circuit for design feedback acquisition, so that the circuit area is reduced, the miniaturization design and EMC design of the system are facilitated, the backlight abnormal reset function and the defogging function are added, and the normal operation capability of the backlight plate in the environment with the temperature and humidity and easy dewing is improved.

The foregoing shows and describes the general principles, essential features, and advantages of the utility model. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are merely illustrative of the principles of the utility model, but that various changes and modifications may be made without departing from the spirit and scope of the utility model, which fall within the scope of the utility model as claimed. The scope of the utility model is defined by the appended claims and equivalents thereof.

Claims

1. A domestic constant-current backlight board is characterized by comprising: the backlight control device comprises a power supply assembly, a DC-DC conversion unit, a backlight control unit, a backlight driving unit, a backlight abnormal reset unit and a defogging unit, wherein the power supply assembly is electrically connected with the DC-DC conversion unit, the backlight control unit and the defogging unit are both electrically connected with the power output end of the DC-DC conversion unit, the defogging unit is electrically connected with the power supply assembly, the backlight driving unit is electrically connected with the liquid crystal driving assembly, the backlight control unit is electrically connected with the backlight driving unit, the backlight driving unit receives PWM brightness and enabling signals transmitted by the backlight control unit and the liquid crystal driving assembly and outputs backlight signals, backlight brightness is regulated and controlled, the backlight abnormal reset unit is electrically connected with the backlight control unit, and the backlight abnormal reset unit collects backlight signal voltage.

2. The domestic constant-current backlight board as claimed in claim 1, wherein a defogging panel is integrated in the backlight control unit, the defogging panel is electrically connected to the defogging keys, the defogging unit is electrically connected to the defogging panel, and the defogging panel is configured to receive instructions from the defogging keys, generate a defogging signal according to the instructions, and transmit the defogging signal to the defogging unit.

3. The domestic constant-current backlight board as claimed in claim 1, wherein the DC-DC conversion unit adopts HYM2596T-5.0 low voltage DC power supply and SSP1117-3.3 low voltage linear power supply, DC24V power supply is inputted from power supply module, and DC5V is outputted after HYM2596T-5.0 conversion, DC5V is converted into DC3.3V power supply by SSP1117-3.3 to supply power to backlight control unit, and DC5V supplies 5V enable signal to defogging unit at the same time.

4. The domestic constant-current backlight board as claimed in claim 1, wherein the backlight driving unit is composed of a Boost type LED driving control chip XC84624, a JGB200G06A model MOS transistor, an SWPA8050S220MT inductor and a peripheral circuit, converts collected backlight enable signals and PWM signals of the liquid crystal driving assembly into current of the LED backlight to be output, and changes the brightness of the liquid crystal display.

5. The domestic constant-current backlight board as claimed in claim 1, wherein the main chip of the backlight control unit is mainly GD32F103C8T6 single-chip microcomputer.

6. The domestic constant-current backlight board as claimed in claim 1, wherein the backlight abnormal reset unit main chip adopts SGMOP17 as comparison output and is driven by DC3.3V power supply.

7. The domestic constant-current backlight board as claimed in claim 1, wherein the defogging unit is current-driven by a JGB200G06A model MOS transistor, on-off controlled by a UPC817 opto-coupler, the power supply module outputs DC24V as a MOS transistor driving DS pole driving power supply, and the DC-DC conversion unit outputs DC5V as a row MOS transistor driving GS pole bias voltage.