Instrument brightness adjusting circuit

Abstract

The utility model provides an instrument brightness adjusting circuit, which comprises a boost converter, a TFT screen, an MCU chip, an SOC chip, a TFT power supply circuit and an interface, and is characterized in that the boost converter is used for driving an LED array for providing backlight for the TFT screen; the TFT power supply control end of the MCU chip is connected with the control input end of the TFT power supply circuit, and the TFT control end of the MCU chip is connected with the control input end of the boost converter; the power output end of the TFT power supply circuit is connected with the power input end of the interface, the driving output end of the boost converter is connected with the driving input end of the interface, and the differential signal transmission end of the interface is connected with the differential signal transmission end of the SOC chip; the image data output end of the interface is connected with the data input end of the TFT screen, and the data transmission end of the MCU chip is connected with the data transmission end of the SOC chip. According to the utility model, voltage fluctuation can be effectively coped, and the brightness stability is ensured by intelligently and automatically adjusting the backlight brightness of the instrument.

Description

Technical Field

[0001] The utility model relates to the technical field of automotive instrument control, and particularly relates to an instrument brightness adjustment circuit. Background Art

[0002] Liquid crystal display technology has been widely applied in multiple fields, such as mobile phones and automotive instrument panels. Under different lighting conditions, such as passing through a tunnel, cloudy days or at night, the liquid crystal display module needs to adapt to these changes to provide the best display effect. Therefore, it is necessary to adjust the backlight brightness according to the ambient light intensity.

[0003] However, the existing liquid crystal display module may encounter voltage fluctuation problems when adjusting the backlight, which will cause the backlight brightness to be unstable, and further affect the clarity and readability of the displayed content. Summary of the Utility Model

[0004] The utility model aims to at least solve the technical problems existing in the prior art, and particularly innovatively provides an instrument brightness adjustment circuit.

[0005] To achieve the above object of the utility model, the utility model provides an instrument brightness adjustment circuit, including: a boost converter, a TFT screen, an MCU chip, an SOC chip, a TFT power supply circuit and an interface. The boost converter is used to drive the LED array that provides backlight for the TFT screen.

[0006] The TFT power control terminal of the MCU chip is connected to the control input terminal of the TFT power supply circuit, and the TFT control terminal of the MCU chip is connected to the control input terminal of the boost converter; the power output terminal of the TFT power supply circuit is connected to the power input terminal of the interface, the drive output terminal of the boost converter is connected to the drive input terminal of the interface, and the differential signal transmission terminal of the interface is connected to the differential signal transmission terminal of the SOC chip; the image data output terminal of the interface is connected to the data input terminal of the TFT screen, and the data transmission terminal of the MCU chip is connected to the data transmission terminal of the SOC chip.

[0007] Further, the TFT power supply circuit is used to convert the power supply +3.3VSW into the power supply +3.3V_TFT. The TFT power supply circuit includes:

[0008] The emitter of the triode Q1, the first end of the capacitor CB14, and the first end of the resistor RB59 are connected to the power supply +3.3VSW; the collector of the triode Q1 outputs the power supply +3.3V_TFT and is connected to the first end of the resistor RB21, and the second end of the resistor RB21 is connected to the power ground.

[0009] The base of transistor Q1 is connected to the second end of capacitor CB14, the second end of resistor RB59, and the first end of resistor RB24. The second end of resistor RB24 is connected to the collector of transistor QB6. The base of transistor QB6 is connected to the first end of resistor RB23 and the first end of resistor RB22. The second end of resistor RB23 is connected to the TFT screen power enable end of the MCU chip; the second end of resistor RB22 is connected to the power ground, and the emitter of transistor QB6 is connected to the power ground.

[0010] The power supply +3.3V_TFT is the core power supply source of the TFT screen, and its switching state is precisely controlled by the MCU chip. When the MCU chip issues a startup command, it first triggers the conduction of transistor QB6. Subsequently, this conduction state further activates transistor Q1, causing it to also enter the conduction state. At this point, the power supply +3.3V_TFT is successfully output to the TFT screen to power it.

[0011] Furthermore, the power supply +3.3VSW is obtained through a power supply module, and the power supply module includes a primary power supply circuit and a secondary power supply circuit. The primary power supply circuit converts the power supply +VBATT into the power supply +5VSW and the power supply +5VCAN, and the secondary power supply circuit converts the power supply +5VSW into the power supply +3.3VSW.

[0012] Furthermore, the primary power supply circuit includes a power chip U2 and a power chip U11:

[0013] The self-boosting terminal BOOT of the power chip U2 is connected to the first end of the resistor R21, the second end of the resistor R21 is connected to the first end of the capacitor C17, the second end of the capacitor C17 is connected to the cathode of the diode D9, the first end of the resistor R22, the switch control terminal SW of U2, and the first end of the inductor L1; the cathode of the diode D9 is connected to the power ground; the second end of the resistor R22 is connected to the first end of the capacitor C19, and the second end of the capacitor C19 is connected to the power ground;

[0014] The second end of the inductor L1 is connected to the first end of the capacitor C20, the first end of the capacitor C21, the first end of the capacitor C22, the first end of the capacitor C23, and the first end of the resistor R23. The second end of the inductor L1 outputs the power supply +5VSW (5V); the second end of the capacitor C20, the second end of the capacitor C21, the second end of the capacitor C22, and the second end of the capacitor C23 are connected to the power ground; wherein the capacitor C23 is a polar capacitor.

[0015] The output voltage feedback terminal FB of the power chip U2, the second end of the resistor R23, and the first end of the resistor R24 are connected, and the second end of the resistor R24 is connected to the power ground;

[0016] The ground terminal GND of the power chip U2 is connected to the power ground;

[0017] The soft start terminal SS of the power supply chip U2 is connected to the first terminal of the capacitor C18, and the second terminal of the capacitor C18 is connected to the power ground;

[0018] The power input terminal VIN of the power supply chip U2 is connected to the first terminal of the capacitor C14, the first terminal of the capacitor C15, the first terminal of the capacitor C16, and the first terminal of the resistor R18; the second terminals of the capacitor C14, the capacitor C15, and the capacitor C16 are connected to the power ground; the second terminal of the resistor R18 is connected to the power +VBATT;

[0019] The enable terminal EN of the power supply chip U2 is connected to the first terminal of the resistor R19, the first terminal of the capacitor C13, and the first terminal of the resistor R16; the second terminal of the resistor R16 is connected to the enable terminal of the MCU chip for controlling the power supply chip U2. The second terminal of the capacitor C13 is connected to the power ground, and the second terminal of the resistor R19 is connected to the power ground;

[0020] The frequency control terminal RT / CLK of the power supply chip U2 is connected to the first terminal of the resistor R20, and the second terminal of the resistor R20 is connected to the power ground;

[0021] The power input terminal VIN of the power supply chip U11 is connected to the negative electrode of the diode D5, the positive electrode of the polarized capacitor C7, and the first terminal of the capacitor C8. The negative electrode of the polarized capacitor C7 and the second terminal of the capacitor C8 are respectively connected to the power ground; the positive electrode of the diode D5 is connected to the power +VBATT;

[0022] The power output terminal OUT of the power supply chip U11 is connected to the first terminal of the capacitor C9, the first terminal of the capacitor C166, and the first terminal of the resistor R3. The power output terminal OUT of the power supply chip U11 outputs the power +5VCAN; the second terminal of the resistor R3 outputs the power +5VSW; the second terminals of the capacitor C9 and the capacitor C166 are connected to the power ground;

[0023] The ground terminal GND of the power supply chip U11 is connected to the power ground.

[0024] Among them, the resistor R22, the capacitor C19, and the diode D9 are reserved components.

[0025] Furthermore, the secondary power supply circuit includes:

[0026] The power input terminal VIN of the power supply chip U3, the first terminal of the resistor R25, the first terminal of the resistor R101, the first terminal of the capacitor C24, and the first terminal of the capacitor C26 are connected to the power supply +5VSW; the second terminal of the capacitor C24 and the second terminal of the capacitor C26 are connected to the power supply ground; the second terminal of the resistor R25 is connected to the power supply indication terminal PG of the power supply chip U3; the second terminal of the resistor R101 is connected to the first terminal of the capacitor C37 and the enable terminal EN of the power supply chip U3; the second terminal of the capacitor C37 is connected to the power supply ground;

[0027] The ground terminal GND of the power supply chip U3 is connected to the power supply ground;

[0028] The switching output terminal SW of the power supply chip U3 is connected to the first terminal of the inductor L2, and the second terminal of the inductor L2 is connected to the power output terminal VOUT of the power supply chip U3, the first terminal of the resistor RO3, the first terminal of the capacitor C30, the first terminal of the capacitor C34, and the first terminal of the capacitor C35; the power output terminal VOUT of the power supply chip U3 outputs the power supply +3.3VSW (3.3V); the second terminal of the capacitor C34 and the second terminal of the capacitor C35 are connected to the power supply ground;

[0029] The feedback terminal FB of the power supply chip U3 is connected to the second terminal of the resistor RO3, the second terminal of the capacitor C30, and the first terminal of the resistor RO1; the second terminal of the resistor RO1 is connected to the power supply ground;

[0030] The soft start terminal SS of the power supply chip U3 is connected to the first terminal of the capacitor C28, and the second terminal of the capacitor C28 is connected to the power supply ground.

[0031] Further, the MCU chip includes a key control circuit:

[0032] The power supply +5VCAN is connected to the first terminal of the resistor R100, and the second terminal of the resistor R100 is connected to the first terminal of the resistor R98, the first terminal of the resistor R5, the first terminal of the resistor R6, the first terminal of the resistor R17, the first terminal of the resistor R97, and the first terminal of the resistor R99; the second terminal of the resistor R5 is connected to the first terminal of the first key, the second terminal of the resistor R6 is connected to the first terminal of the second key, the second terminal of the resistor R17 is connected to the first terminal of the third key, the second terminal of the resistor R97 is connected to the first terminal of the fourth key, and the second terminal of the resistor R99 is connected to the first terminal of the fifth key; the second terminals of the second key, the third key, the fourth key, and the fifth key are connected to the power supply ground;

[0033] The second terminal of the resistor R98 is connected to the first terminal of the capacitor C155 and the key input terminal of the MCU chip; the second terminal of the capacitor C155 is connected to the power supply ground.

[0034] The first button is the increase button, the second button is the decrease button, the third button is the confirmation button, the fourth button is the down button, and the fifth button is the up button. The first button and the second button are used to increase or decrease the screen brightness; the fourth button and the fifth button are used to select other function items.

[0035] Further, the data transmission end of the MCU chip is connected to the data transmission end of the SOC chip, including:

[0036] The signal receiving end of the SOC chip is connected to the first end of the resistor R562 and the collector of the triode QG3. The base of the triode QG3 is connected to the first end of the capacitor CG4 and the first end of the resistor RG8; the emitter of the triode QG3 is connected to the first end of the resistor RG9 and the data sending end of the MCU chip. The second end of the resistor RG9, the second end of the capacitor CG4, and the second end of the resistor RG8 are connected to the power supply +5VCAN; the second end of the resistor R562 and the first end of the resistor R561 are connected to the power supply VDD33_IO; the second end of the resistor R561 is connected to the signal sending end of the SOC chip and the emitter of the triode QG4.

[0037] The base of the triode QG4 is connected to the first end of the capacitor CG3 and the first end of the resistor RG6; the emitter of the triode QG4 is connected to the first end of the resistor RG7 and the data receiving end of the MCU chip; the second end of the capacitor CG3, the second end of the resistor RG6, and the second end of the resistor RG7 are connected to the power supply +5VCAN.

[0038] Further, the MCU chip includes:

[0039] The power supply terminals VDD1 and VDDA of the MCU chip U12 are connected to the first end of the resistor R4, the first end of the capacitor C151, the first end of the capacitor C150, and the first end of the capacitor C149; the second ends of the capacitor C151, the capacitor C150, and the capacitor C149 are connected to the power supply ground; the second end of the resistor R4 is connected to the power supply +5VCAN;

[0040] The data transmission end PA0 of the MCU chip U12 is connected to the first end of the resistor RR48;

[0041] The data transmission end PA1 of the MCU chip U12 is connected to the first end of the resistor RR45;

[0042] The data transmission end PB13 of the MCU chip U12 is connected to the first end of the resistor RR44;

[0043] The second ends of the resistor RR48, the resistor RR45, and the resistor RR44 are connected to the control end of the AMP chip;

[0044] The power supply terminal VDD2 of the MCU chip U12, the first terminal of the capacitor C154, the first terminal of the capacitor C153, and the first terminal of the capacitor C152 are connected to the power supply +5VCAN; the second terminal of the capacitor C154, the second terminal of the capacitor C153, and the second terminal of the capacitor C152 are connected to the power supply ground;

[0045] The crystal oscillator input terminal PA12 of the MCU chip U12 is connected to the first terminal of the resistor R114, the third terminal of the crystal oscillator Y2, and the first terminal of the capacitor C146; the second terminal of the resistor R114 is connected to the crystal oscillator output terminal PA15 of the MCU chip U12, the first terminal of the capacitor C147, and the first terminal of the crystal oscillator Y2; the fourth terminal of the crystal oscillator Y2, the first terminal of the crystal oscillator Y2, the second terminal of the capacitor C146, and the second terminal of the capacitor C147 are all connected to the power supply ground.

[0046] Furthermore, the circuit of the interface includes:

[0047] The first terminal, second terminal, third terminal of the interface J13, the first terminal of the capacitor C137, the first terminal of the capacitor C138, and the first terminal of the capacitor C139 are connected to the power supply TFT_BL+; the fifth terminal of the interface J13 is connected to the first terminal of the resistor R85 and the first terminal of the resistor R84. The second terminal of the resistor R85 is connected to the temperature signal terminal of the MCU chip, and the second terminal of the resistor R84 is connected to the power supply +5VCAN; the grounding terminal of the interface J13 is connected to the power supply ground;

[0048] The eighth terminal of the interface J13 is connected to the first terminal of the resistor R81 and the second terminal of the capacitor C139. The second terminal of the resistor R81 is connected to the series 2 current input terminal LED2 of the boost converter U10; the ninth terminal of the interface J13 is connected to the first terminal of the resistor R82 and the second terminal of the capacitor C138. The second terminal of the resistor R82 is connected to the series 3 current input terminal LED3 of the boost converter U10. The tenth terminal of the interface J13 is connected to the first terminal of the resistor R83 and the second terminal of the capacitor C137. The second terminal of the resistor R83 is connected to the series 4 current input terminal LED4 of the boost converter U10;

[0049] The twelfth and thirteenth terminals of the interface J13 are connected to the first terminal of the resistor R76, the first terminal of the capacitor C135, and the first terminal of the capacitor C136. The second terminal of the capacitor C135 and the second terminal of the capacitor C136 are connected to the power supply ground. The second terminal of the resistor R76 is connected to the power supply +3.3V_TFT;

[0050] The eighteenth terminal of interface J13 is connected to the first terminal of resistor R90 and the first terminal of resistor R89. The nineteenth terminal of interface J13 is connected to the first terminal of resistor R92 and the first terminal of resistor R91. The second terminal of resistor R90 and the second terminal of resistor R92 are connected to the power supply +3.3V_TFT. The second terminal of resistor R89 and the second terminal of resistor R91 are connected to the power ground.

[0051] The twentieth terminal of interface J13 is connected to the first terminal of resistor R75 and the first terminal of resistor R74. The second terminal of resistor R75 is connected to the power ground. The second terminal of resistor R74 is connected to the standby mode control terminal of the MCU chip.

[0052] The twenty-first terminal of interface J13 is connected to the collector of triode QB1, the first terminal of resistor R72, and the first terminal of capacitor CB13. The second terminal of resistor R72 is connected to the power supply +3.3V_TFT. The base of triode QB1 is connected to the first terminal of resistor R73. The second terminal of resistor R73 is connected to the reset signal terminal of the MCU chip. The emitter of triode QB1 and the second terminal of capacitor CB13 are connected to the power ground.

[0053] The twenty-third, twenty-fourth, twenty-sixth, twenty-seventh, twenty-ninth, thirtieth, thirty-second, thirty-third, thirty-fifth, and thirty-sixth terminals of interface J13 are connected to the differential signal terminals of the SOC chip.

[0054] The thirty-eighth terminal of interface J13 is connected to the first terminal of resistor R93 and the first terminal of resistor R94. The second terminal of resistor R93 is connected to the power supply +5VCAN. The second terminal of resistor R94 is connected to the fault indication terminal of the MCU chip.

[0055] In summary, due to the adoption of the above technical solutions, the power supply circuit and boost converter designed for the TFT screen of the present utility model provide a stable working voltage for the TFT screen. It has sufficient bandwidth and stable output voltage characteristics, and can effectively cope with voltage fluctuations, thereby making the backlight brightness of the intelligent automatic adjustment instrument stable. At the same time, in order to meet the personalized needs of users, the scheme designs a manual fine-tuning function. After the instrument automatically adjusts to the appropriate brightness, the user can make fine adjustments through the buttons. Especially when facing different lighting environments, such as passing through tunnels, cloudy days or nights, this manual fine-tuning function is particularly important, which can ensure that the information display is always clearly readable. Using buttons instead of a touch screen for fine-tuning not only makes the operation more accurate but also effectively prevents accidental touches, improving the user experience.

[0056] Additional aspects and advantages of the present utility model will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The above and / or additional aspects and advantages of the present utility model will become apparent and be readily understood from the following description of embodiments in conjunction with the accompanying drawings, where:

[0058] Figure 1 is a connection schematic diagram of the present utility model.

[0059] Figure 2 is a circuit connection schematic diagram of the boost converter of the present utility model.

[0060] Figure 3 is a circuit connection schematic diagram of the interface of the present utility model.

[0061] Figure 4 is the power supply circuit of the TFT screen of the present utility model.

[0062] Figures 5(a) to 5(d) is a circuit connection schematic diagram of the MCU chip of the present utility model.

[0063] Figures 6(a) to 6(b) is a schematic diagram of the primary power supply circuit of the power supply module of the present utility model.

[0064] Figure 7 is a schematic diagram of the secondary power supply circuit of the power supply module of the present utility model. Detailed Embodiments

[0065] The embodiments of the present utility model will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary only for explaining the present utility model and should not be construed as limiting the present utility model.

[0066] The present utility model provides an instrument brightness adjustment circuit, as Figure 1 shown, including: a boost converter, a TFT screen, an MCU chip, an SOC chip, a TFT power supply circuit, and an interface. The boost converter is used to drive an LED array that provides backlight for the TFT screen;

[0067] The TFT power control terminal of the MCU chip is connected to the control input terminal of the TFT power supply circuit,

[0068] The TFT control terminal of the MCU chip is connected to the control input terminal of the boost converter;

[0069] The power output terminal of the TFT power supply circuit is connected to the power input terminal of the interface,

[0070] The drive output terminal of the boost converter is connected to the drive input terminal of the interface,

[0071] The differential signal transmission end of the interface is connected to the differential signal transmission end of the SOC chip; the image data output end of the interface is connected to the data input end of the TFT screen, and the data transmission end of the MCU chip is connected to the data transmission end of the SOC chip.

[0072] The process of automatically adjusting the brightness of the instrument brightness adjustment circuit is as follows: (1) Initialize the circuit: After the system is powered on, the MCU chip will perform initialization operations, including configuring registers, setting the clock source, initializing the interface, etc. (2) Real-time collect light data: The light sensor starts to collect the light brightness data of the internal and external environments of the vehicle body in real time and transmits it to the MCU chip. (3) Calculate the backlight brightness value: The MCU chip calculates the backlight brightness value of the display screen suitable for the current ambient light through a preset algorithm based on the received light data. (4) Send a control signal: The MCU chip sends a control signal to the TFT power supply circuit and the boost converter to adjust the power supply voltage supplied to the TFT screen and the brightness of the LED array. (5) Display image data: The SOC chip processes the image data and transmits it to the TFT screen through the interface for display. (6) Continuously monitor and adjust: The MCU chip will continuously monitor the change of the light data and adjust the backlight brightness value as needed to ensure that the brightness of the display screen is always coordinated with the ambient light.

[0073] The circuit connection of the boost converter is as Figure 2 shown. The boost converter U10 is connected to the MCU chip and the interface J13. The boost converter U10 is a boost converter with a 4-channel current source and uses a peak current control PWM control structure to regulate the boost converter. The 4-channel current source is applied to the LED cathode interface to adjust the LED brightness. In addition, the interface J13 is also connected to the MCU chip, the SOC chip, and the TFT screen.

[0074] The dimming terminal DIM of the boost converter U10 is connected to the first terminal of the resistor R57 and the backlight brightness adjustment terminal of the MCU chip, and the backlight brightness adjustment of the TFT screen is realized by the pulse width modulation signal output by the backlight brightness adjustment terminal of the MCU chip. The second terminal of the resistor R57 is connected to the power ground; the dimming mode setting terminal MIX / AD of the boost converter U10 is connected to the first terminal of the resistor R56, and the second terminal of the resistor R56 is connected to the power ground; the switching frequency setting / synchronization pin terminal FREQ / SYNC of the boost converter U10 is connected to the first terminal of the resistor R58, and the second terminal of the resistor R58 is connected to the power ground; the enable terminal EN of the boost converter U10 is connected to the first terminal of the resistor R55 and the enable control terminal of the MCU chip to control the on / off state of the backlight module TFT screen. When the TFT_BL_EN signal is at a high level, the backlight module is activated and lit; when the signal is at a low level, the TFT screen of the backlight module is turned off. The second terminal of the resistor R55 is connected to the power ground; the clock input terminal SCL / PSE of the boost converter U10 is connected to the first terminal of the resistor R60 and the first terminal of the resistor R53, and the second terminal of the resistor R53 is connected to the power VCC; the data input terminal SDA / PSE of the boost converter U10 is connected to the second terminal of the resistor R60 and the first terminal of the resistor R51, and the second terminal of the resistor R51 is connected to the power ground;

[0075] The compensation terminal COMP of the boost converter U10 is connected to the first terminal of the resistor R59 and the first terminal of the capacitor C120. The second terminal of the resistor R59 is connected to the first terminal of the capacitor C121. The second terminals of the capacitor C120 and the capacitor C121 are connected to the power ground; the fault flag terminal FF of the boost converter U10 is connected to the first terminal of the resistor R61 and the first terminal of the resistor R62. The second terminal of the resistor R61 is connected to the power +5VCAN, and the second terminal of the resistor R62 is connected to the backlight fault indication terminal of the MCU chip; when there are situations such as power failure, abnormal brightness, overheating, etc., the MCU can receive the TFT_BL_FLT signal and take corresponding measures, such as turning off the backlight system, sending a warning signal, or restarting the backlight system, etc., to ensure the safe and stable operation of the device. The LED current setting terminal ISET of the boost converter U10 is connected to the first terminal of the resistor R64 and the first terminal of the resistor R63. The second terminals of the resistor R64 and the resistor R63 are connected to the power ground; the ground terminal AGND of the boost converter U10 is connected to the power ground;

[0076] The series 4 current input terminal LED4 of the boost converter U10, the series 3 current input terminal LED3 of the boost converter U10, and the series 2 current input terminal LED2 of the boost converter U10 are all connected to the LED transmission interface of the interface J13; the series 1 current input terminal LED1 of the boost converter U10 and the boost converter ground terminal PGND of the boost converter U10 are connected to the power ground;

[0077] The power inductor connection terminal SW of the boost converter U10 is connected to the first end of the inductor L13, the first end of the resistor R71, and the positive electrode of the diode D11. The second end of the resistor R71 is connected to the first end of the capacitor C130, and the second end of the capacitor C130 is connected to the power ground;

[0078] The negative electrode of the diode D11 is connected to the first ends of the capacitors C131, C132, C133, C134, the first end of the resistor R78, and the first end of the resistor R80. The second end of the resistor R80 outputs the power supply TFT_BL+; the second ends of the capacitors C131, C132, C133, and C134 are all connected to the power ground; the second end of the resistor R78 is connected to the first end of the resistor R79, the second end of the resistor R79 is connected to the first end of the resistor R77 and the overvoltage protection terminal OVP of the boost converter U10, and the second end of the resistor R77 is connected to the power ground; the capacitor C134 is a polarized capacitor.

[0079] The configuration voltage terminal STH of the boost converter U10 is connected to the first end of the resistor R70 and the first end of the capacitor C129. The second ends of the resistor R70 and the capacitor C129 are connected to the power ground; the IC address setting terminal ADR of the boost converter U10 is connected to the first end of the resistor R69 and the first end of the capacitor C128. The second ends of the resistor R69 and the capacitor C128 are connected to the power ground; the power supply terminal VCC of the boost converter U10, the first end of the resistor R66, and the negative electrode of the diode D10 are connected to the power supply VCC; the second end of the resistor R66 and the positive electrode of the diode D10 are connected to the first end of the capacitor C127, and the second end of the capacitor C127 is connected to the power ground; the power input terminal VIN of the boost converter U10 is connected to the first end of the capacitor C125 and the first end of the resistor R65. The second end of the resistor R65, the second end of the inductor L13, the first ends of the capacitors C122, C123, C124, and C126 are connected to the power supply +VBATT; the second ends of the capacitors C122, C123, C124, and C126 are connected to the power ground; the capacitor C122 is a polarized capacitor. The heat dissipation terminal of the boost converter U10 and the second end of the capacitor C125 are connected to the power ground.

[0080] Among them, the capacitor C128 is a reserved component, and the model of the boost converter U10 is MPQ3364.

[0081] The circuit connection of the interface of the present utility model is as Figure 3 shown.

[0082] The first end, second end, third end of interface J13, the first end of capacitor C137, the first end of capacitor C138, and the first end of capacitor C139 are connected to power supply TFT_BL+; the fifth end of interface J13 is connected to the first end of resistor R85 and the first end of resistor R84. The second end of resistor R85 is connected to the temperature signal terminal of the MCU chip, and the second end of resistor R84 is connected to power supply +5VCAN; the ground terminal of interface J13 is connected to the power ground.

[0083] The eighth end of interface J13 is connected to the first end of resistor R81 and the second end of capacitor C139. The second end of resistor R81 is connected to the series 2 current input terminal LED2 of boost converter U10; the ninth end of interface J13 is connected to the first end of resistor R82 and the second end of capacitor C138. The second end of resistor R82 is connected to the series 3 current input terminal LED3 of boost converter U10. The tenth end of interface J13 is connected to the first end of resistor R83 and the second end of capacitor C137. The second end of resistor R83 is connected to the series 4 current input terminal LED4 of boost converter U10.

[0084] The twelfth end and thirteenth end of interface J13 are connected to the first end of resistor R76, the first end of capacitor C135, and the first end of capacitor C136. The second ends of capacitor C135 and capacitor C136 are connected to the power ground, and the second end of resistor R76 is connected to power supply +3.3V_TFT.

[0085] The eighteenth end of interface J13 is connected to the first end of resistor R90 and the first end of resistor R89. The nineteenth end of interface J13 is connected to the first end of resistor R92 and the first end of resistor R91. The second ends of resistor R90 and resistor R92 are connected to power supply +3.3V_TFT; the second ends of resistor R89 and resistor R91 are connected to the power ground.

[0086] The twentieth end of interface J13 is connected to the first end of resistor R75 and the first end of resistor R74. The second end of resistor R75 is connected to the power ground, and the second end of resistor R74 is connected to the standby mode control terminal of the MCU chip.

[0087] The twenty-first end of interface J13 is connected to the collector of triode QB1, the first end of resistor R72, and the first end of capacitor CB13. The second end of resistor R72 is connected to power supply +3.3V_TFT; the base of triode QB1 is connected to the first end of resistor R73, and the second end of resistor R73 is connected to the reset signal terminal of the MCU chip; the emitter of triode QB1 and the second end of capacitor CB13 are connected to the power ground.

[0088] The 23rd, 24th, 26th, 27th, 29th, 30th, 32nd, 33rd, 35th and 36th terminals of the interface J13 are connected to the differential signal terminals of the SOC chip;

[0089] The thirty-eighth terminal of the interface J13 is connected to the first end of the resistor R93 and the first end of the resistor R94, the second end of the resistor R93 is connected to the power supply +5VCAN, and the second end of the resistor R94 is connected to the fault indication terminal of the MCU chip.

[0090] The power supply circuit of the TFT screen is connected as follows Figure 4 As shown: the emitter of transistor Q1, the first end of capacitor CB14, and the first end of resistor RB59 are connected to the power supply +3.3VSW; the collector of transistor Q1 outputs the power supply +3.3V_TFT and is connected to the first end of resistor RB21, and the second end of resistor RB21 is connected to the power ground;

[0091] The base of transistor Q1 is connected to the second end of capacitor CB14, the second end of resistor RB59, and the first end of resistor RB24. The second end of resistor RB24 is connected to the collector of transistor QB6. The base of transistor QB6 is connected to the first end of resistor RB23 and the first end of resistor RB22. The second end of resistor RB23 is connected to the TFT screen power enable end of the MCU chip; the second end of resistor RB22 is connected to the power ground, and the emitter of transistor QB6 is connected to the power ground.

[0092] The power supply +3.3V_TFT is the core power supply source of the TFT screen, and its switching state is precisely controlled by the MCU chip. When the MCU chip issues a startup command, it first triggers the conduction of transistor QB6. Subsequently, this conduction state further activates transistor Q1, causing it to also enter the conduction state. At this point, the power supply +3.3V_TFT is successfully output to the TFT screen to power it.

[0093] The circuit connection of the MCU chip is shown in Figure 5(a). The power supply terminals VDD1 and VDDA of the MCU chip U12 are connected to the first end of the resistor R4, the first end of the capacitor C151, the first end of the capacitor C150, and the first end of the capacitor C149; the second end of the capacitor C151, the second end of the capacitor C150, and the second end of the capacitor C149 are connected to the power ground; the second end of the resistor R4 is connected to the power supply +5VCAN;

[0094] The data transmission terminal PA0 of the MCU chip U12 is connected to the first end of the resistor RR48;

[0095] The data transmission terminal PA1 of the MCU chip U12 is connected to the first end of the resistor RR45;

[0096] The data transmission terminal PB13 of the MCU chip U12 is connected to the first end of the resistor RR44;

[0097] The second end of the resistor RR48, the second end of the resistor RR45, and the second end of the resistor RR44 are connected to the control terminal of the AMP chip;

[0098] The power supply terminal VDD2 of the MCU chip U12, the first end of the capacitor C154, the first end of the capacitor C153, and the first end of the capacitor C152 are connected to the power supply +5VCAN; the second end of the capacitor C154, the second end of the capacitor C153, and the second end of the capacitor C152 are connected to the power supply ground;

[0099] The crystal oscillator input terminal PA12 of the MCU chip U12 is connected to the first end of the resistor R114, the third end of the crystal oscillator Y2, and the first end of the capacitor C146; the second end of the resistor R114 is connected to the crystal oscillator output terminal PA15 of the MCU chip U12, the first end of the capacitor C147, and the first end of the crystal oscillator Y2; the fourth end of the crystal oscillator Y2, the first end of the crystal oscillator Y2, the second end of the capacitor C146, and the second end of the capacitor C147 are all connected to the power supply ground.

[0100] The model of the MCU chip U12 is AC78013FDLA.

[0101] Figure 5(b) is a level conversion circuit for communication between the MCU chip and the SOC chip, which ensures the correct transmission of signals through level conversion. Specifically: the signal receiving terminal of the SOC chip is connected to the first end of the resistor R562 and the collector of the triode QG3, and the base of the triode QG3 is connected to the first end of the capacitor CG4 and the first end of the resistor RG8; the emitter of the triode QG3 is connected to the first end of the resistor RG9 and the data sending terminal of the MCU chip, and the second end of the resistor RG9, the second end of the capacitor CG4, and the second end of the resistor RG8 are connected to the power supply +5VCAN; the second end of the resistor R562 and the first end of the resistor R561 are connected to the power supply VDD33_IO; the second end of the resistor R561 is connected to the signal sending terminal of the SOC chip and the emitter of the triode QG4;

[0102] The base of the triode QG4 is connected to the first end of the capacitor CG3 and the first end of the resistor RG6; the emitter of the triode QG4 is connected to the first end of the resistor RG7 and the data receiving terminal of the MCU chip; the second end of the capacitor CG3, the second end of the resistor RG6, and the second end of the resistor RG7 are connected to the power supply +5VCAN.

[0103] Through the above level conversion circuit, signals are transmitted between SOC chips and MCU chips with different voltage levels. Specifically, it converts the 3.3V signal of the SOC chip into a 5V signal that the MCU chip can recognize, and vice versa. The following is the control logic of the circuit:

[0104] (1)Signal transmission from SOC to MCU (through QG3 and RG9):

[0105] When the signal receiving end (ITE3966_SDA_RX) of the SOC chip outputs a high level (3.3V), the current flows through R562 into the collector of QG3. This makes QG3 conduct, and the voltage at its emitter is close to 0V (grounded), pulling down the voltage of the data sending end (MCU_SCL_TX) of the MCU chip through RG9, causing it to output a low level (0V). When the SOC chip outputs a low level, QG3 is cut off, and RG9 pulls up MCU_SCL_TX to 5V, outputting a high level.

[0106] (2)Signal transmission from MCU to SOC (through QG4 and RG7):

[0107] When the data receiving end (MCU_SDA_RX) of the MCU chip outputs a high level (5V), the current flows through RG7 into the emitter of QG4. This makes QG4 conduct, and the voltage at its base is close to 0V, pulling down the voltage of the signal sending end (ITE3966_SCL_TX) of the SOC chip through RG6, causing it to output a low level. When the MCU chip outputs a low level, QG4 is cut off, and RG6 pulls up ITE3966_SCL_TX to 3.3V, outputting a high level.

[0108] The MCU chip also has a partial circuit of the debug port, as shown in Figure 5(c). The key control circuit of the MCU chip is shown in Figure 5(d). The power supply +5VCAN is connected to the first end of resistor R100, and the second end of resistor R100 is connected to the first ends of resistor R98, resistor R5, resistor R6, resistor R17, resistor R97, and resistor R99; the second end of resistor R5 is connected to the first end of the first key, the second end of resistor R6 is connected to the first end of the second key, the second end of resistor R17 is connected to the first end of the third key, the second end of resistor R97 is connected to the first end of the fourth key, and the second end of resistor R99 is connected to the first end of the fifth key; the second ends of the second key, the third key, the fourth key, and the fifth key are connected to the power supply ground;

[0109] The second end of resistor R98 is connected to the first end of capacitor C155 and the key input end of the MCU chip; the second end of capacitor C155 is connected to the power supply ground.

[0110] The circuit of the power supply module is as Figures 6(a) to 6(b) ~ Figure 7As shown in the figure. The primary power supply circuit includes power supply chips U2 and U11. The primary power supply circuit converts the power supply +VBATT (12V) into power supplies +5VSW (5V) and +5VCAN (5V); when the power supply +5VSW output by the power supply chip U2 meets the static low power consumption in the sleep state, there is no need to use the power supply chip U11, and the power supply +5VSW is connected through the resistor R3 to output the power supply +5VCAN. If it does not meet the requirement, the power supply chip U11 is adopted, and there is no resistor R3 at this time; the power supply chip U11 converts the power supply +VBATT (12V) into the power supply +5VCAN (5V).

[0111] The self-boost terminal BOOT of the power supply chip U2 is connected to the first end of the resistor R21. The second end of the resistor R21 is connected to the first end of the capacitor C17. The second end of the capacitor C17 is connected to the negative electrode of the diode D9, the first end of the resistor R22, the switch control terminal SW of U2, and the first end of the inductor L1. The negative electrode of the diode D9 is connected to the power supply ground. The second end of the resistor R22 is connected to the first end of the capacitor C19. The second end of the capacitor C19 is connected to the power supply ground.

[0112] The second end of the inductor L1 is connected to the first ends of the capacitors C20, C21, C22, C23, and the first end of the resistor R23. The second end of the inductor L1 outputs the power supply +5VSW (5V). The second ends of the capacitors C20, C21, C22, C23 are connected to the power supply ground. Among them, the capacitor C23 is a polarized capacitor.

[0113] The output voltage feedback terminal FB of the power supply chip U2, the second end of the resistor R23, and the first end of the resistor R24 are connected. The second end of the resistor R24 is connected to the power supply ground.

[0114] The ground terminal GND of the power supply chip U2 is connected to the power supply ground.

[0115] The soft start terminal SS of the power supply chip U2 is connected to the first end of the capacitor C18. The second end of the capacitor C18 is connected to the power supply ground.

[0116] The power input terminal VIN of the power supply chip U2 is connected to the first ends of the capacitors C14, C15, C16, and the first end of the resistor R18. The second ends of the capacitors C14, C15, C16 are connected to the power supply ground. The second end of the resistor R18 is connected to the power supply +VBATT.

[0117] The enable terminal EN of the power supply chip U2 is connected to the first terminal of the resistor R19, the first terminal of the capacitor C13, and the first terminal of the resistor R16; the second terminal of the resistor R16 is connected to the enable terminal of the MCU chip for controlling the power supply chip U2. The second terminal of the capacitor C13 is connected to the power ground, and the second terminal of the resistor R19 is connected to the power ground;

[0118] The frequency control terminal RT / CLK of the power supply chip U2 is connected to the first terminal of the resistor R20, and the second terminal of the resistor R20 is connected to the power ground.

[0119] The model of the power supply chip U2 is SCT2432STER.

[0120] The power input terminal VIN of the power supply chip U11 is connected to the negative electrode of the diode D5, the positive electrode of the polarized capacitor C7, and the first terminal of the capacitor C8. The negative electrode of the polarized capacitor C7 and the second terminal of the capacitor C8 are respectively connected to the power ground; the positive electrode of the diode D5 is connected to the power +VBATT;

[0121] The power output terminal OUT of the power supply chip U11 is connected to the first terminal of the capacitor C9, the first terminal of the capacitor C166, and the first terminal of the resistor R3. The power output terminal OUT of the power supply chip U11 outputs the power +5VCAN; the second terminal of the resistor R3 outputs the power +5VSW; the second terminals of the capacitor C9 and the capacitor C166 are connected to the power ground;

[0122] The ground terminal GND of the power supply chip U11 is connected to the power ground.

[0123] The model of the power supply chip U11 is SCT71403F50Q

[0124] The power input terminal VIN of the power supply chip U3, the first terminal of the resistor R25, the first terminal of the resistor R101, the first terminal of the capacitor C24, and the first terminal of the capacitor C26 are connected to the power +5VSW; the second terminals of the capacitor C24 and the capacitor C26 are connected to the power ground; the second terminal of the resistor R25 is connected to the power indicator terminal PG of the power supply chip U3; the second terminal of the resistor R101 is connected to the first terminal of the capacitor C37 and the enable terminal EN of the power supply chip U3; the second terminal of the capacitor C37 is connected to the power ground;

[0125] The ground terminal GND of the power supply chip U3 is connected to the power ground;

[0126] The switching output terminal SW of the power supply chip U3 is connected to the first end of the inductor L2, and the second end of the inductor L2 is connected to the power output terminal VOUT of the power supply chip U3, the first end of the resistor RO3, the first end of the capacitor C30, the first end of the capacitor C34, and the first end of the capacitor C35; the power output terminal VOUT of the power supply chip U3 outputs the power supply +3.3VSW (3.3V); the second ends of the capacitor C34 and the capacitor C35 are connected to the power ground;

[0127] The feedback terminal FB of the power supply chip U3 is connected to the second end of the resistor RO3, the second end of the capacitor C30, and the first end of the resistor RO1; the second end of the resistor RO1 is connected to the power ground;

[0128] The soft start terminal SS of the power supply chip U3 is connected to the first end of the capacitor C28, and the second end of the capacitor C28 is connected to the power ground.

[0129] The model of the power supply chip U3 is SCT2130.

[0130] The TFT power supply of the present utility model sequentially obtains the power supplies +5VSW and +5VCAN through the primary power supply circuit of the power supply module, and then obtains the power supply +3.3VSW through the secondary power supply circuit; and then the power supply +3.3VSW is converted into the power supply +3.3V_TFT suitable for the TFT screen by the power supply circuit of the TFT screen. In this process, the power supply is stepped down in stages, and the stability and reliability of the power supply in each link are ensured. In addition, the working condition of the power supply in the sleep state of the instrument is also considered to ensure better implementation of the solution.

[0131] Although the embodiments of the present utility model have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present utility model. The scope of the present utility model is defined by the claims and their equivalents.

Claims

1. An instrument brightness adjustment circuit, characterized in that, Comprising: A boost converter, a TFT screen, an MCU chip, an SOC chip, a TFT power supply circuit, and an interface. The boost converter is used to drive an LED array that provides backlight for the TFT screen; The TFT power control terminal of the MCU chip is connected to the control input terminal of the TFT power supply circuit, and the TFT control terminal of the MCU chip is connected to the control input terminal of the boost converter; The power output terminal of the TFT power supply circuit is connected to the power input terminal of the interface, the drive output terminal of the boost converter is connected to the drive input terminal of the interface, and the differential signal transmission terminal of the interface is connected to the differential signal transmission terminal of the SOC chip; The image data output terminal of the interface is connected to the data input terminal of the TFT screen, and the data transmission terminal of the MCU chip is connected to the data transmission terminal of the SOC chip.

2. The brightness adjustment circuit of an instrument according to claim 1, wherein, The TFT power supply circuit is used to convert the power supply +3.3VSW into the power supply +3.3V_TFT. The TFT power supply circuit includes: The emitter of transistor Q1, the first terminal of capacitor CB14, and the first terminal of resistor RB59 are connected to the power supply +3.3VSW; The collector of transistor Q1 outputs the power supply +3.3V_TFT and is connected to the first terminal of resistor RB21, and the second terminal of resistor RB21 is connected to the power supply ground; The base of transistor Q1 is connected to the second terminal of capacitor CB14, the second terminal of resistor RB59, and the first terminal of resistor RB24. The second terminal of resistor RB24 is connected to the collector of transistor QB6. The base of transistor QB6 is connected to the first terminal of resistor RB23 and the first terminal of resistor RB22. The second terminal of resistor RB23 is connected to the TFT screen power enable terminal of the MCU chip; The second terminal of resistor RB22 is connected to the power supply ground, and the emitter of transistor QB6 is connected to the power supply ground.

3. The instrument brightness adjustment circuit according to claim 2, characterized in that, The power supply +3.3VSW is obtained through a power supply module. The power supply module includes a primary power supply circuit and a secondary power supply circuit. The primary power supply circuit converts the power supply +VBATT into the power supplies +5VSW and +5VCAN, and the secondary power supply circuit converts the power supply +5VSW into the power supply +3.3VSW.

4. The instrument brightness adjustment circuit according to claim 3, wherein The primary power supply circuit includes power supply chips U2 and U11: The self-boost terminal BOOT of power supply chip U2 is connected to the first terminal of resistor R21. The second terminal of resistor R21 is connected to the first terminal of capacitor C17. The second terminal of capacitor C17 is connected to the negative electrode of diode D9, the first terminal of resistor R22, the switch control terminal SW of U2, and the first terminal of inductor L1; The negative electrode of diode D9 is connected to the power supply ground; The second terminal of resistor R22 is connected to the first terminal of capacitor C19, and the second terminal of capacitor C19 is connected to the power supply ground; The second terminal of inductor L1 is connected to the first terminals of capacitors C20, C21, C22, C23, and the first terminal of resistor R23. The second terminal of inductor L1 outputs the power supply +5VSW; The second terminals of capacitors C20, C21, C22, and C23 are connected to the power supply ground; The output voltage feedback terminal FB of the power supply chip U2 is connected to the second terminal of the resistor R23 and the first terminal of the resistor R24. The second terminal of the resistor R24 is connected to the power supply ground. The ground terminal GND of the power supply chip U2 is connected to the power supply ground. The soft start terminal SS of the power supply chip U2 is connected to the first terminal of the capacitor C18. The second terminal of the capacitor C18 is connected to the power supply ground. The power input terminal VIN of the power supply chip U2 is connected to the first terminal of the capacitor C14, the first terminal of the capacitor C15, the first terminal of the capacitor C16, and the first terminal of the resistor R18. The second terminals of the capacitors C14, C15, and C16 are connected to the power supply ground. The second terminal of the resistor R18 is connected to the power supply +VBATT. The enable terminal EN of the power supply chip U2 is connected to the first terminal of the resistor R19, the first terminal of the capacitor C13, and the first terminal of the resistor R16. The second terminal of the resistor R16 is connected to the enable terminal of the MCU chip. The second terminal of the capacitor C13 is connected to the power supply ground. The second terminal of the resistor R19 is connected to the power supply ground. The frequency control terminal RT / CLK of the power supply chip U2 is connected to the first terminal of the resistor R20. The second terminal of the resistor R20 is connected to the power supply ground. The power input terminal VIN of the power supply chip U11 is connected to the negative electrode of the diode D5, the positive electrode of the polarized capacitor C7, and the first terminal of the capacitor C8. The negative electrode of the polarized capacitor C7 and the second terminal of the capacitor C8 are respectively connected to the power supply ground. The positive electrode of the diode D5 is connected to the power supply +VBATT. The power output terminal OUT of the power supply chip U11 is connected to the first terminal of the capacitor C9, the first terminal of the capacitor C166, and the first terminal of the resistor R3. The power output terminal OUT of the power supply chip U11 outputs the power supply +5VCAN. The second terminal of the resistor R3 outputs the power supply +5VSW. The second terminals of the capacitors C9 and C166 are connected to the power supply ground. The ground terminal GND of the power supply chip U11 is connected to the power supply ground.

5. The instrument brightness adjustment circuit according to claim 3, characterized in that, The secondary power supply circuit includes: The power input terminal VIN of the power supply chip U3, the first terminal of the resistor R25, the first terminal of the resistor R101, the first terminal of the capacitor C24, and the first terminal of the capacitor C26 are connected to the power supply +5VSW. The second terminals of the capacitors C24 and C26 are connected to the power supply ground. The second terminal of the resistor R25 is connected to the power supply indication terminal PG of the power supply chip U3. The second terminal of the resistor R101 is connected to the first terminal of the capacitor C37 and the enable terminal EN of the power supply chip U3. The second terminal of the capacitor C37 is connected to the power supply ground. The ground terminal GND of the power supply chip U3 is connected to the power supply ground. The switching output terminal SW of the power supply chip U3 is connected to the first terminal of the inductor L2. The second terminal of the inductor L2 is connected to the power output terminal VOUT of the power supply chip U3, the first terminal of the resistor RO3, the first terminal of the capacitor C30, the first terminal of the capacitor C34, and the first terminal of the capacitor C35. The power output terminal VOUT of the power supply chip U3 outputs the power supply +3.3VSW. The second terminals of the capacitors C34 and C35 are connected to the power supply ground. The feedback terminal FB of the power supply chip U3 is connected to the second terminal of the resistor RO3, the second terminal of the capacitor C30, and the first terminal of the resistor RO1; the second terminal of the resistor RO1 is connected to the power supply ground; The soft start terminal SS of the power supply chip U3 is connected to the first terminal of the capacitor C28, and the second terminal of the capacitor C28 is connected to the power supply ground.

6. The instrument brightness adjustment circuit according to claim 1, characterized in that, The MCU chip includes a key control circuit: The power supply +5VCAN is connected to the first terminal of the resistor R100, and the second terminal of the resistor R100 is connected to the first terminal of the resistor R98, the first terminal of the resistor R5, the first terminal of the resistor R6, the first terminal of the resistor R17, the first terminal of the resistor R97, and the first terminal of the resistor R99; the second terminal of the resistor R5 is connected to the first terminal of the first key, the second terminal of the resistor R6 is connected to the first terminal of the second key, the second terminal of the resistor R17 is connected to the first terminal of the third key, the second terminal of the resistor R97 is connected to the first terminal of the fourth key, and the second terminal of the resistor R99 is connected to the first terminal of the fifth key; the second terminals of the second key, the third key, the fourth key, and the fifth key are connected to the power supply ground; The second terminal of the resistor R98 is connected to the first terminal of the capacitor C155 and the key input terminal of the MCU chip; the second terminal of the capacitor C155 is connected to the power supply ground.

7. The instrument brightness adjustment circuit according to claim 1, characterized in that The data transmission terminal of the said MCU chip is connected to the data transmission terminal of the SOC chip, including: The signal receiving terminal of the SOC chip is connected to the first terminal of the resistor R562 and the collector of the triode QG3, and the base of the triode QG3 is connected to the first terminal of the capacitor CG4 and the first terminal of the resistor RG8; the emitter of the triode QG3 is connected to the first terminal of the resistor RG9 and the data sending terminal of the MCU chip, and the second terminal of the resistor RG9, the second terminal of the capacitor CG4, and the second terminal of the resistor RG8 are connected to the power supply +5VCAN; the second terminal of the resistor R562 and the first terminal of the resistor R561 are connected to the power supply VDD33_IO; the second terminal of the resistor R561 is connected to the signal sending terminal of the SOC chip and the emitter of the triode QG4; The base of the triode QG4 is connected to the first terminal of the capacitor CG3 and the first terminal of the resistor RG6; the emitter of the triode QG4 is connected to the first terminal of the resistor RG7 and the data receiving terminal of the MCU chip; the second terminal of the capacitor CG3, the second terminal of the resistor RG6, and the second terminal of the resistor RG7 are connected to the power supply +5VCAN.

8. The instrument brightness adjustment circuit according to claim 1, characterized in that, The MCU chip includes: The power supply terminals VDD1 and VDDA of the MCU chip U12 are connected to the first terminal of the resistor R4, the first terminal of the capacitor C151, the first terminal of the capacitor C150, and the first terminal of the capacitor C149; the second terminals of the capacitor C151, the capacitor C150, and the capacitor C149 are connected to the power supply ground; the second terminal of the resistor R4 is connected to the power supply +5VCAN; The data transmission terminal PA0 of the MCU chip U12 is connected to the first terminal of the resistor RR48; The data transmission terminal PA1 of the MCU chip U12 is connected to the first terminal of the resistor RR45; The data transmission terminal PB13 of the MCU chip U12 is connected to the first terminal of the resistor RR44; The second terminal of resistor RR48, the second terminal of resistor RR45, and the second terminal of resistor RR44 are connected to the control terminal of the AMP chip; The power supply terminal VDD2 of MCU chip U12, the first terminal of capacitor C154, the first terminal of capacitor C153, and the first terminal of capacitor C152 are connected to the power supply +5VCAN; the second terminal of capacitor C154, the second terminal of capacitor C153, and the second terminal of capacitor C152 are connected to the power supply ground; The crystal oscillator input terminal PA12 of MCU chip U12 is connected to the first terminal of resistor R114, the third terminal of crystal oscillator Y2, and the first terminal of capacitor C146; the second terminal of resistor R114 is connected to the crystal oscillator output terminal PA15 of MCU chip U12, the first terminal of capacitor C147, and the first terminal of crystal oscillator Y2; the fourth terminal of crystal oscillator Y2, the first terminal of crystal oscillator Y2, the second terminal of capacitor C146, and the second terminal of capacitor C147 are all connected to the power supply ground.

9. The instrument brightness adjustment circuit according to claim 1, wherein The circuit of the said interface includes: The first terminal, second terminal, third terminal of interface J13, the first terminal of capacitor C137, the first terminal of capacitor C138, and the first terminal of capacitor C139 are connected to the power supply TFT_BL+; the fifth terminal of interface J13 is connected to the first terminal of resistor R85 and the first terminal of resistor R84, the second terminal of resistor R85 is connected to the temperature signal terminal of the MCU chip, and the second terminal of resistor R84 is connected to the power supply +5VCAN; the ground terminal of interface J13 is connected to the power supply ground; The eighth terminal of interface J13 is connected to the first terminal of resistor R81 and the second terminal of capacitor C139, the second terminal of resistor R81 is connected to the series 2 current input terminal LED2 of boost converter U10; the ninth terminal of interface J13 is connected to the first terminal of resistor R82 and the second terminal of capacitor C138, the second terminal of resistor R82 is connected to the series 3 current input terminal LED3 of boost converter U10, the tenth terminal of interface J13 is connected to the first terminal of resistor R83 and the second terminal of capacitor C137, the second terminal of resistor R83 is connected to the series 4 current input terminal LED4 of boost converter U10; The twelfth terminal and thirteenth terminal of interface J13 are connected to the first terminal of resistor R76, the first terminal of capacitor C135, and the first terminal of capacitor C136, the second terminal of capacitor C135 and the second terminal of capacitor C136 are connected to the power supply ground, and the second terminal of resistor R76 is connected to the power supply +3.3V_TFT; The eighteenth terminal of interface J13 is connected to the first terminal of resistor R90 and the first terminal of resistor R89, the nineteenth terminal of interface J13 is connected to the first terminal of resistor R92 and the first terminal of resistor R91, the second terminal of resistor R90 and the second terminal of resistor R92 are connected to the power supply +3.3V_TFT; the second terminal of resistor R89 and the second terminal of resistor R91 are connected to the power supply ground; The twentieth terminal of interface J13 is connected to the first terminal of resistor R75 and the first terminal of resistor R74, the second terminal of resistor R75 is connected to the power supply ground, and the second terminal of resistor R74 is connected to the standby mode control terminal of the MCU chip. The twenty-first terminal of interface J13 is connected to the collector of triode QB1, the first terminal of resistor R72, and the first terminal of capacitor CB13. The second terminal of resistor R72 is connected to the power supply +3.3V_TFT. The base of triode QB1 is connected to the first terminal of resistor R73, and the second terminal of resistor R73 is connected to the reset signal terminal of the MCU chip. The emitter of triode QB1 and the second terminal of capacitor CB13 are connected to the power supply ground. The twenty-third, twenty-fourth, twenty-sixth, twenty-seventh, twenty-ninth, thirtieth, thirty-second, thirty-third, thirty-fifth, and thirty-sixth terminals of interface J13 are connected to the differential signal terminals of the SOC chip. The thirty-eighth terminal of interface J13 is connected to the first terminal of resistor R93 and the first terminal of resistor R94. The second terminal of resistor R93 is connected to the power supply +5VCAN, and the second terminal of resistor R94 is connected to the fault indication terminal of the MCU chip.

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