Digital display vehicle air conditioner controller

Abstract

The application discloses a digital display vehicle air conditioner controller, which comprises an MCU control module, a power module, a sensor acquisition module, an air conditioner load driving module, an isolation detection module, a key control module, a key backlight module and a digital display driving module; the power module is compatible with 12V / 24V vehicle power supply and comprises an anti-reverse connection circuit, a surge protection circuit and a filter circuit; the modular driving architecture is adopted, the optical coupling isolation detection module and the digital display driving module are matched, and fault codes can be displayed in real time; through the design of upper and lower double-layer PCB boards, electromagnetic interference and power fluctuation can be blocked through physical isolation. The digital display vehicle air conditioner controller improves the universality of the power supply and the circuit integration, can quickly locate faults to reduce the maintenance difficulty, enhances the anti-interference capability, optimizes the operation experience, and is suitable for various automobile air conditioning systems.

Description

Technical Field

[0001] This utility model relates to the field of automotive electronic control technology, and in particular to a digital display automotive air conditioning controller. Background Technology

[0002] As automotive air conditioning systems demand higher control precision and versatility, existing automotive air conditioning controllers are increasingly revealing numerous technical shortcomings. These shortcomings primarily manifest in low integration, with power supply, drive, and detection circuits being distributed across a wide range of components, requiring numerous external independent parts. This results in larger controller sizes, limited installation space, and increased circuit connection nodes, reducing system stability. Furthermore, existing products lack effective fault detection and feedback mechanisms. When the air conditioning load malfunctions, repair personnel must systematically check each circuit and component, making it difficult to pinpoint the fault quickly and accurately, leading to high repair difficulty and time consumption. Additionally, since power supply and control circuits are often integrated on the same PCB board, power fluctuations and electromagnetic interference from inductive load switches can easily intrude into the control signal, causing MCU misjudgments and display anomalies, affecting air conditioning control precision and failing to meet the usage requirements of automotive air conditioning systems. Utility Model Content

[0003] In view of the above situation and to overcome the defects of the prior art, the purpose of this utility model is to provide a digital display vehicle air conditioning controller.

[0004] The technical solution is: a digital display automotive air conditioning controller, including an MCU control module, a power supply module, a sensor acquisition module, an air conditioning load drive module, an isolation detection module, a button control module, a button backlight module, and a digital display drive module;

[0005] The MCU control module is electrically connected to the sensor acquisition module, the air conditioner load drive module, the isolation detection module, the button control module, the button backlight module, and the digital display drive module, respectively, and is used to receive the signals transmitted by each module and output control commands.

[0006] The power module is used to receive 12V / 24V automotive power input, and after voltage processing, outputs a working voltage that is compatible with each module.

[0007] The sensor acquisition module is used to acquire automotive air conditioning environment sensor signals and power supply voltage feedback signals, and transmit the acquired signals to the MCU control module after processing.

[0008] The air conditioner load drive module is used to receive instructions from the MCU control module, drive the air conditioner relays and actuators to operate, and cooperate with the isolation detection module to provide feedback on the load working status.

[0009] The isolation detection module is used to achieve high and low voltage signal isolation, detect the low-level active signal of the air conditioning load drive module, and transmit the detection result to the MCU control module.

[0010] The button control module is used to collect the trigger signals of user operation buttons and transmit the signals to the MCU control module to execute the corresponding air conditioning control function;

[0011] The button backlight module is used to adjust the brightness of the button backlight to adapt to the vehicle power status and external signal control requirements.

[0012] The digital display driver module is used to receive the control signal after level conversion from the MCU control module, and drive the digital display screen to display air conditioner-related status information and fault codes.

[0013] Preferably, the power module includes a reverse connection protection circuit, a surge protection circuit, a filter circuit, a power conversion chip, and a voltage regulator chip; the 12V / 24V automotive input power is processed sequentially by the reverse connection protection circuit, the surge protection circuit, and the filter circuit before being input to the power conversion chip; the power conversion chip converts the processed automotive power into a first operating voltage; another path is input to the voltage regulator chip, which converts the first operating voltage into a second operating voltage.

[0014] Preferably, the sensor acquisition module includes an environmental sensor signal acquisition sub-circuit and a power supply voltage signal acquisition sub-circuit;

[0015] The environmental sensor signal acquisition sub-circuit includes sensors for acquiring vehicle interior temperature and defrosting status. Each sensor converts the acquired physical signal into an electrical signal through a resistor voltage divider, and after being processed by a current-limiting resistor, it is transmitted to the corresponding ADC pin of the MCU control module through a filter circuit.

[0016] The power supply voltage signal acquisition sub-circuit acquires the operating voltage output by the power module through a resistor voltage divider sampling method, and transmits the sampled and converted voltage signal to the MCU control module after processing by a filtering circuit.

[0017] Preferably, the air conditioner load drive module includes a relay drive sub-circuit and a prompt sound drive sub-circuit;

[0018] In the relay drive sub-circuit, the relays for loads such as evaporator fans, compressors, and generators all adopt low-side control mode and are controlled by a drive chip. The input terminal of the drive chip is connected to the IO port of the MCU control module, and the output terminal is grounded. When the MCU control module outputs a control signal, it triggers the drive chip to conduct, thereby controlling the corresponding relay to operate. Each relay is connected in parallel with a freewheeling protection element to suppress the back electromotive force generated when the relay is disconnected.

[0019] The prompt tone driver sub-circuit is integrated into the idle channel of the driver chip and is used for fault alarms and operation prompts.

[0020] Preferably, the isolation detection module uses an isolation element as its core and employs a low-side effective detection method. The primary side of the isolation element is connected to the vehicle power supply via a current-limiting resistor, and the negative terminal of the primary side is connected in series with a reverse connection protection element before being connected to the relay load signal terminal to be detected. The secondary side of the isolation element is connected to the operating voltage, and the output terminal of the secondary side is connected to the IO pin of the MCU control module via a filter circuit. When a low-level signal is detected on the primary side, the isolation element is turned on and outputs a corresponding signal to the MCU control module, thereby realizing the isolation detection of high and low voltage signals.

[0021] Preferably, the button control module adopts an independent button structure, including multiple tactile switches. One end of each tactile switch is grounded, and the other end is connected to the corresponding IO pin of the MCU control module via a pull-up resistor. When the user triggers the button, the level of the corresponding IO pin changes, and the MCU control module recognizes this and executes the corresponding air conditioning control function.

[0022] Preferably, the button backlight module includes multiple button backlight adjustment sub-circuits, powered by an isolated power supply; the light source of the button backlight adjustment sub-circuit is a light-emitting element corresponding to each button, and the light-emitting element is connected to the isolated power supply through a switching element; when there is no input from the vehicle power supply, an external control signal controls the button backlight to be fully lit; when there is input from the vehicle power supply, the MCU control module adjusts the conduction degree of the switching element through an output control signal to realize the adjustment of the button backlight brightness; at the same time, the backlight brightness can be compensated by the signal provided by the vehicle power supply.

[0023] Preferably, the digital display driving module includes a level conversion sub-circuit and a display driving sub-circuit;

[0024] The level conversion sub-circuit uses a conversion driver device to achieve level adaptation between the MCU control module and the display driver sub-circuit;

[0025] The display driver sub-circuit uses a driver chip and a shift register, which work together to drive the digital display screen to show the air conditioner status, fault codes, and power parameters.

[0026] Preferably, a double-layer PCB design is adopted, wherein:

[0027] The lower PCB board houses the power components for the power supply module and the air conditioning load drive module;

[0028] The upper PCB board houses the control circuitry for the MCU control module, sensor acquisition module, isolation detection module, button control module, button backlight module, and digital display driver module.

[0029] The upper and lower PCB boards are connected by an electrical connection structure to transmit power and control signals, while physical isolation reduces mutual interference between circuits.

[0030] Preferably, the MCU control module includes a microcontroller unit and peripheral circuits. The microcontroller unit is a GD32E230 microcontroller, and the peripheral circuits include a crystal oscillator circuit, a reset circuit, and a configuration circuit.

[0031] Through the above technical solutions, the beneficial effects of this utility model are as follows: The digital display automotive air conditioning controller of this application adopts a modular drive architecture, reducing independent components, improving circuit integration, and reducing size. Through optocoupler isolation detection and digital fault code display, fault points can be quickly located, significantly reducing repair difficulty; the upper and lower double-layer PCB layout physically isolates power components from sensitive control circuits, significantly improving anti-interference capabilities. Meanwhile, independent buttons ensure precise operation, adjustable backlight adapts to different lighting conditions, and the digital display screen clearly shows the status, optimizing the user experience and fully meeting the practical needs of automotive air conditioning. Attached Figure Description

[0032] Figure 1 This is a system module structure diagram of this utility model.

[0033] Figure 2 This is a schematic diagram of the MCU peripheral interface circuit according to an embodiment of the present invention.

[0034] Figure 3 This is a schematic diagram illustrating the connection principle of the reverse connection protection circuit and the surge protection circuit according to an embodiment of this utility model.

[0035] Figure 4 This is a schematic diagram illustrating the connection principle between the filter circuit and the power conversion chip according to an embodiment of the present invention.

[0036] Figure 5 This is a schematic diagram of a 3.3V power supply circuit according to an embodiment of the present invention.

[0037] Figure 6 This is a schematic diagram of the sensor acquisition module circuit according to an embodiment of the present invention.

[0038] Figure 7 This is a schematic diagram of the ULN2003 driver chip circuit according to an embodiment of the present invention.

[0039] Figure 8 This is a schematic diagram of an air conditioner load relay drive circuit according to an embodiment of the present invention.

[0040] Figure 9 This is a schematic diagram of the prompt tone driver sub-circuit of one embodiment of the present invention.

[0041] Figure 10 This is a circuit diagram of an isolation detection module according to an embodiment of the present invention.

[0042] Figure 11 This is a schematic diagram of the button control module circuit according to an embodiment of the present invention.

[0043] Figure 12 This is a schematic diagram of the button backlight module circuit according to an embodiment of the present invention.

[0044] Figure 13 This is a schematic diagram of a level conversion sub-circuit according to an embodiment of the present invention.

[0045] Figure 14 This is a schematic diagram of the display driver sub-circuit of one embodiment of the present invention.

[0046] Figure 15 This is a wiring diagram of an embodiment of the electrical connection structure of this utility model. Detailed Implementation

[0047] The foregoing and other technical contents, features and effects of this utility model are described in conjunction with the appendix below. Figure 1 To be continued Figure 15 The detailed description of the embodiments will make this clear. All structural details mentioned in the following embodiments are based on the accompanying drawings.

[0048] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings.

[0049] like Figure 1 As shown, the digital display automotive air conditioning controller of the present invention includes an MCU control module, a power supply module, a sensor acquisition module, an air conditioning load drive module, an isolation detection module, a button control module, a button backlight module, and a digital display drive module. These circuits work together to achieve comprehensive control of the air conditioning system. The specific technical solution is as follows:

[0050] like Figure 2 As shown, the MCU control module is the core control unit of the digital display automotive air conditioning controller. Its core chip is the GD32E230 microcontroller U2, which features low power consumption and high computing efficiency, meeting the real-time control requirements of automotive air conditioning systems. To ensure stable MCU operation, the module is equipped with a complete peripheral circuit: a matching 16MHz crystal oscillator, measuring 11.4*4.5*3.8mm, in an HC-49SMD package. The two ends of the crystal oscillator are connected to the MCU's PF0 pin (OSCIN) and PF1 pin (OSCOUT) respectively, providing a stable clock signal to ensure the timing accuracy of various control commands; an RC reset circuit is connected to the MCU's NRST pin, which triggers the MCU to reset when the controller powers on or encounters an abnormality, ensuring stable operation from the initial state; and a configuration resistor R12 is connected to the MCU's BOOT0 pin, which switches between MCU program burning and normal operation modes, providing support for controller production debugging and subsequent maintenance.

[0051] As the core of the controller's signal processing and command output, the MCU control module establishes electrical connections with the sensor acquisition module, air conditioning load drive module, isolation detection module, button control module, button backlight module, and digital display drive module via wires. At the signal receiving end, the MCU control module receives environmental parameter signals and power supply voltage feedback signals from the sensor acquisition module, air conditioning load status detection signals from the isolation detection module, and user operation trigger signals from the button control module. At the signal processing and command output end, the MCU control module performs logical operations and analysis on the received signals, and outputs load control commands to the air conditioning load drive module based on the results. This drives the evaporator fan speed control module, compressor clutch, generator excitation coil, and other load actions. It also outputs brightness adjustment commands to the button backlight module to achieve adaptive control of the button backlight brightness, and outputs display control commands to the digital display drive module to display the air conditioning operating status, fault codes, and temperature parameters on the digital display screen, ultimately achieving comprehensive and precise control of the automotive air conditioning system.

[0052] The power module receives 12V / 24V input power from the vehicle and outputs a stable operating voltage that is compatible with the various functional modules of the controller through multiple protection mechanisms and voltage conversion processing. At the same time, it resists abnormal voltages and interference signals in the vehicle circuit, providing energy guarantee for the reliable operation of the entire controller. The module specifically includes a reverse connection protection circuit, a surge protection circuit, a filter circuit, a power conversion chip, and a voltage regulator chip. All parts work together to achieve safe power processing and accurate conversion.

[0053] During the power input phase, the automotive 12V / 24V power supply first enters the reverse connection protection circuit, such as... Figure 3 As shown, this circuit uses S3M / DO-214AB diode D1 as its core component. Its unidirectional conductivity effectively prevents subsequent circuit components from burning out due to reverse polarity connection when an external power supply is connected, thus avoiding hardware failures caused by incorrect power connection from the source. The power supply, after being protected against reverse connection, then enters the surge protection circuit. This circuit uses SMCJ28CA / DO-214AB TVS surge protector D2, which can quickly respond to transient high-voltage surges common in automotive circuits. For example, power fluctuations during vehicle startup or instantaneous high voltages generated by external electromagnetic interference can be clamped within a safe range through its own breakdown and current dissipation, preventing high voltage damage to subsequent voltage conversion chips and ensuring the overall power supply safety of the circuit.

[0054] After achieving dual protection, the power supply still needs to pass through a filtering circuit to optimize signal quality, such as... Figure 4As shown, the filter circuit consists of a 220μF / 50V low-frequency filter capacitor C6 and a 0.1μF high-frequency filter capacitor C2. Capacitor C6 filters out low-frequency interference signals in the power supply, suppressing the impact of slow voltage fluctuations on the circuit. Capacitor C2 is used to eliminate high-frequency interference signals and reduce voltage noise caused by electromagnetic radiation. Through dual filtering of high and low frequency interference, the power signal input to the voltage conversion chip reaches a pure and stable state, laying the foundation for the subsequent voltage conversion process.

[0055] The purified power supply, after protection and filtering, is finally input to the LM2596-5.0 / TO-263-5 power conversion chip U5. This chip has wide voltage input adaptability and can stably convert 12V / 24V automotive power to a 5V first operating voltage. This voltage serves as the base power supply voltage for some modules within the controller. Within the module, it is further divided into two paths for targeted processing: the first 5V voltage first connects to the MBRS3100T3G / DO-214AB electrostatic discharge protection diode D3. After electrostatic discharge protection, it passes through an LC filter circuit composed of inductor L1, capacitor C7, and capacitor C3 to further filter out residual ripple generated during voltage conversion. Subsequently, it mainly supplies power to the digital display driver module and the button backlight module; the second 5V voltage is directly input to the ASM1117 voltage regulator chip U1, such as... Figure 5 As shown, the chip has high-precision voltage regulation characteristics, which can further convert 5V voltage into a second operating voltage of 3.3V. This voltage mainly supplies the MCU control module, sensor acquisition module and air conditioning load drive module, providing low-noise and highly stable power supply support for these core control and signal acquisition modules, ensuring the accurate implementation of their logic operation and signal processing functions.

[0056] The sensor acquisition module collects key physical signals required for the operation of the automotive air conditioning system. Through circuit processing, these signals are converted into electrical signals recognizable by the MCU, providing accurate data support for the MCU to formulate air conditioning control strategies and determine system operating status. This module employs an architecture combining voltage divider resistor sampling and RC filtering, comprising two sub-circuits: an environmental sensor signal acquisition sub-circuit and a power supply voltage signal acquisition sub-circuit. The two sub-circuits operate independently with consistent signal processing logic, ensuring the accuracy and stability of the acquired data.

[0057] Among them, the environmental sensor signal acquisition sub-circuit is designed for the core environmental parameters of air conditioner operation, such as... Figure 6As shown, the system includes three types of data acquisition objects: a room temperature sensor, a defrost 1 sensor, and a defrost 2 sensor. These sensors are used to acquire the real-time interior temperature, the evaporator defrost status, and the defrost status of other key components of the air conditioning system, respectively. During signal conversion, the room temperature sensor signal is first divided by the sensor's own resistor and resistor R8, converting the resistance signal corresponding to the temperature change into a voltage signal. This voltage signal then passes through an RC filter circuit composed of resistors R5 and C3 to filter out electromagnetic interference and fluctuation noise during signal transmission before finally being transmitted to the ADC pin of the MCU. The defrost 1 sensor signal is divided by the sensor resistor and resistor R7, then processed by an RC filter circuit composed of resistors R4 and C2 before being connected to the MCU. The defrost 2 sensor signal is divided by the sensor resistor and resistor R6, then processed by an RC filter circuit composed of resistors R3 and C1 before being transmitted to the MCU. By precisely matching the voltage divider resistors and using RC filtering for noise reduction, all three types of environmental signals can be converted into stable electrical signals within the range of 0-3.3V. The MCU can analyze the voltage values ​​of these signals to accurately determine whether the interior temperature needs to be adjusted, whether the evaporator is frosted and needs to be defrosted, and then dynamically adjust parameters such as the air conditioning's cooling / heating intensity and fan speed to ensure the comfort and safety of the air conditioning operation.

[0058] The power supply voltage signal acquisition sub-circuit is used to monitor the stability of the controller's own power supply system, preventing air conditioner control failure due to power supply abnormalities. For example... Figure 6 As shown, this sub-circuit samples the operating voltage output by the power module through a voltage divider network composed of R10 and R9. This includes both the 5V output from the power conversion chip and the 3.3V converted by the voltage regulator chip. The divided voltage signal passes through an RC filter circuit composed of R11 and C4 to further eliminate sampling errors caused by power fluctuations, and is finally transmitted to the ADC pin of the MCU. The MCU reads the voltage value of this sampled signal in real time and compares it with a preset normal voltage range. If the voltage is detected to be lower or higher than the safety threshold, it determines that the power module is abnormal and triggers the protection mechanism. On one hand, the power fault code is displayed on the digital display screen via the digital display driver module to remind maintenance personnel to troubleshoot; on the other hand, a command is output to the air conditioning load driver module to cut off the power supply to non-essential loads such as the compressor and fan, leaving only the core control circuit running. This avoids load burnout or MCU misjudgment due to abnormal voltage, comprehensively ensuring the safety of the controller power supply system and the air conditioning load.

[0059] The entire sensor acquisition module utilizes a standardized voltage divider and filter circuit design to achieve synchronous acquisition of environmental parameters and power status. All acquired signals are directly connected to the MCU's ADC pins, eliminating the need for additional signal amplification or conversion chips. This simplifies the circuit structure, increases integration, and ensures real-time and accurate signal transmission. Through logical analysis of these acquired signals, the MCU can dynamically optimize the air conditioning control strategy based on environmental changes and monitor the power system's operating status in real time, providing crucial data support for the stable and reliable operation of the air conditioning controller.

[0060] The air conditioner load drive module receives control signals from the MCU control module and precisely controls the on / off state and operating status of key air conditioner loads through the drive circuit. For example... Figure 7 and 8 As shown, the module uses the ULN2003 driver chip as its core driving device. This chip has multi-channel output capability, which can effectively reduce the number of independent external driver circuits connected to the MCU and greatly simplify the circuit layout. The specific connection logic is as follows: the MCU's control pins are directly connected to the input terminals of the ULN2003, and the output terminals of the ULN2003 are respectively connected to the negative terminals of the control terminals of each air conditioning load relay. The positive terminals of all relay control terminals are uniformly connected to the automotive 12V / 24V power supply. Through this connection method, when the MCU outputs a control signal to the ULN2003, the corresponding output channel of the ULN2003 is turned on, forming a complete circuit at the relay control terminal, causing the relay to energize and thus driving the corresponding air conditioning load to start working. Conversely, when the MCU stops outputting control signals, the ULN2003 output channel is turned off, the relay is disconnected, and the load stops running, achieving precise switching control of the load.

[0061] The air conditioning loads controlled by this module are all key components ensuring the normal operation of the air conditioning system. These include the evaporator fan speed control module, the compressor clutch, and the generator excitation coil. The evaporator fan speed control module's start / stop and speed adjustment are controlled by corresponding relays, directly affecting the vehicle's air circulation speed and cooling / heating efficiency. The compressor clutch's on / off state determines whether the compressor operates, making it a core control node for the air conditioning cooling function. The generator excitation coil is associated with the generator's power supply stability to the air conditioning system, ensuring sufficient power supply during load operation. By centrally driving these loads, the module achieves unified control of the air conditioning system's core functions, avoiding circuit redundancy problems caused by distributed drives.

[0062] To address the circuit safety risks associated with relay operation, the module is equipped with a freewheeling diode for each relay. This diode is connected in parallel across the relay and its function is to suppress the back electromotive force generated when the relay disconnects. When the relay switches from the engaged state to the disengaged state, the coil experiences a sudden drop in current, generating a momentary high-voltage back electromotive force. If not suppressed, this can easily damage the ULN2003 driver chip or the MCU control pins. The freewheeling diode, through its unidirectional conductivity, guides the back electromotive force into the circuit and dissipates it, effectively protecting the driver chip and MCU, and extending the circuit's lifespan.

[0063] In addition, the module also integrates buzzer driver functionality using the unused output channels of the ULN2003, such as... Figure 9 As shown, the negative terminal of the buzzer is connected to one of the idle output terminals of the ULN2003, while the positive terminal is connected to a 5V operating voltage. When the MCU detects a load fault through the isolation detection module, such as a relay failing to engage as instructed or an abnormal power outage of the load, it will output a control signal to the corresponding channel of the ULN2003, causing the buzzer to power on and sound. Combined with the fault code displayed by the digital display driver module, this forms a dual fault warning mechanism of "audio prompt + visual prompt," helping users or maintenance personnel to quickly detect abnormalities.

[0064] The isolation detection module uses an optocoupler as the core isolation component. Utilizing the optocoupler's photoelectric conversion characteristics, it achieves physical isolation between high and low voltage signals, preventing interference signals from the automotive 12V / 24V high-voltage circuits from entering the 3.3V low-voltage control circuit, thus ensuring the signal detection accuracy of the MCU control module. The circuit design employs a low-side active detection method, such as... Figure 10 As shown, the specific connection is as follows: The positive terminal of the photodiode on the primary side of the optocoupler is connected to the automotive 12V / 24V power supply through a current-limiting resistor, providing the operating voltage for the primary circuit; the negative terminal of the photodiode on the primary side of the optocoupler is connected in series with a reverse connection protection diode and then connected to the air conditioning load signal terminal to be tested. This reverse connection protection diode can effectively prevent damage to the optocoupler caused by reverse connection of the positive and negative terminals of the signal at the testing terminal, ensuring the safety of the testing unit from the source of the circuit connection; the positive terminal of the transistor on the secondary side of the optocoupler is connected to a 5V operating voltage, and the negative terminal of the secondary side transistor is connected in series with a current-limiting resistor and an RC filter circuit, and finally connected to the detection pin of the MCU control module. The current-limiting resistor is used to limit the current in the secondary circuit to avoid excessive current damaging the MCU pin, and the RC filter circuit is used to filter out noise interference in the detection signal to ensure that the signal transmitted to the MCU is stable and pure.

[0065] During operation, when the air conditioner load is working normally and the detection terminal outputs a low-level signal, the photodiode on the primary side of the optocoupler conducts due to the voltage difference between its two ends. The generated light signal triggers the secondary transistor to conduct, thus forming a circuit on the secondary side. The 5V voltage is transmitted to the MCU detection pin through the conducting transistor and the RC filter circuit. The MCU receives a high-level signal and determines that the corresponding load is working normally. If the air conditioner load malfunctions, there is no low-level signal input at the detection terminal. The photodiode on the primary side of the optocoupler is cut off, and the secondary transistor is also cut off. The MCU detection pin has no voltage input and presents a low-level signal. Based on this, the MCU determines that there is an abnormality in the load and then triggers the subsequent fault handling mechanism.

[0066] The button control module adopts an independent button control architecture, such as... Figure 11 As shown, the system consists of seven individual tactile switches, each corresponding to an independent air conditioning control function. This avoids the command conflicts that may occur with traditional multiplexed buttons, while also simplifying the button signal detection logic and facilitating troubleshooting. SW7 is specifically designed as a power switch, handling the controller's start / stop function. When the user triggers SW7, the module transmits a power control signal to the MCU. Upon receiving the signal, the MCU drives the digital display to light up or turn off, simultaneously starting or stopping the core power supply circuit of the air conditioning system. The remaining six buttons correspond to temperature adjustment, mode switching, and fan speed control functions, including a temperature + button, a temperature - button, a cooling button, a heating button, an internal / external circulation button, and a fan speed control button. Users can directly issue commands to the air conditioning system to adjust the temperature, switch between cooling / heating modes, switch between internal / external circulation, and adjust the fan speed level by triggering the corresponding buttons.

[0067] In terms of circuit connection logic, one end of each tactile switch is directly grounded, while the other end is connected to the corresponding IO pin of the MCU control module through a pull-up resistor. Under normal conditions, the pull-up resistor keeps the MCU's IO pin at a high level. When the user presses a button, the tactile switch closes, and the corresponding IO pin forms a path with ground through the switch, changing the level from high to low. By detecting the level changes of each IO pin in real time, the MCU can accurately identify the type of button triggered by the user and then execute the corresponding control logic. For example, when the user presses the temperature+ button, the MCU detects that the corresponding IO pin is pulled low and then outputs a command to the air conditioning load drive module to control the compressor clutch to extend its working time or the fan to increase its speed, thereby raising the temperature inside the vehicle. When the user presses the internal / external circulation button, the MCU controls the corresponding relay to switch the air conditioning duct, achieving the switching between internal and external circulation modes.

[0068] The button backlight module is directly controlled by an isolated power signal. This power supply method effectively blocks interference signals from other circuits inside the controller from entering the backlight circuit, avoiding problems such as backlight flickering and unstable brightness caused by voltage fluctuations or electromagnetic interference, and ensuring continuous and stable operation of the backlight in the complex electromagnetic environment of automotive applications. Figure 12 As shown, this module includes multiple button backlight adjustment sub-circuits, each containing a 1206 packaged yellow-green LED. Each LED corresponds to a button, ensuring precise matching between the backlight indicator and the operating position of each button. In terms of operating status control, when there is no input from the vehicle power supply, an external control signal can drive the backlight to full brightness, allowing users to quickly locate buttons in dark environments. When there is input from the vehicle power supply, the MCU adjusts the backlight brightness by outputting a PWM wave, adapting to different lighting conditions such as strong daylight and weak nightlight. Simultaneously, it can also perform detail compensation for the backlight brightness using the vehicle power supply's own PWM signal, further optimizing the backlight display effect. The overall design balances circuit anti-interference and component protection while achieving flexible brightness adaptation.

[0069] The digital display drive module is the core unit in the digital display automotive air conditioning controller that realizes the visualization of air conditioning status and fault information. Its core function is to drive the digital display screen to accurately display the in-vehicle temperature, air conditioning operation mode, air volume level and fault code. This module is mainly composed of two parts: level conversion sub-circuit and display drive sub-circuit. The two work together to ensure the stable implementation of the digital display function.

[0070] In the specific implementation, since the control signal output by the MCU is 3.3V, while the digital display driver chip requires a 5V signal to operate normally, the level conversion sub-circuit uses two MMBT5551 / G1 transistors as the core conversion driver devices. For example... Figure 13 As shown, the specific connection is as follows: the control terminal of the MCU is connected to the emitters of transistors Q1 and Q2; the bases of transistors Q1 and Q2 are connected to a 3.3V power supply to ensure that the transistors are in a normally conducting state; and the collectors of transistors Q1 and Q2 are simultaneously connected to a 5V power supply and the control pins of the digital display driver chip. Through this circuit structure, the 3.3V MCU control signal can be converted into a 5V signal, precisely matching the signal requirements of the digital display driver chip, effectively ensuring the normal transmission of control signals between circuits with different voltage levels, and avoiding signal loss or drive failure due to voltage level mismatch.

[0071] like Figure 14As shown, the display driver sub-circuit adopts a collaborative driving architecture, with the ULN2003A driver chip U4 and the 74HC164D / SOP-14 shift register U3 as the core, jointly driving the LNK1950-MA-1 LED digital display screen. The output of the ULN2003A driver chip is connected to the segment power supply terminal of the digital display screen, controlling the illumination of the segment codes to ensure clear display of numbers and characters. The output of the 74HC164D / SOP-14 shift register is connected to the ground terminal of the digital display screen, controlling the digit selection and precisely locating the display digits to be illuminated.

[0072] During operation, the MCU first transmits the control signal to the level conversion sub-circuit. After level conversion, a 5V control signal is generated, which is then sent to the ULN2003A driver chip and the 74HC164D / SOP-14 shift register. With the coordinated operation of these two devices, the digital display accurately shows various information, including real-time in-vehicle temperature, air conditioning operating mode, fan speed level, and fault codes. For example, "E1" represents a room temperature sensor fault, and "E2" represents a compressor relay fault. This intuitive presentation allows users and maintenance personnel to quickly grasp the air conditioning's operating status. If a fault occurs, the code can quickly pinpoint the problem, fully realizing the visualization of the air conditioning status and facilitating troubleshooting.

[0073] This application's digital display automotive air conditioning controller adopts a double-layer PCB design. The lower PCB is dedicated to the complete power-related circuitry of the power module, including reverse connection protection circuitry, surge protection circuitry, voltage conversion chips and filtering components, as well as power components for the air conditioning load drive module, such as the ULN2003 driver chip and relays. These components are prone to power fluctuations, electromagnetic radiation, and back electromotive force during relay switching; concentrating them on the lower layer avoids interference to sensitive control circuits. The upper PCB houses the control circuitry for the MCU control module, sensor acquisition module, isolation detection module, button control module, button backlight module, and digital display drive module. These modules are all low-voltage signal processing units, extremely sensitive to electromagnetic interference; their placement on the upper layer keeps them away from interference sources associated with the lower layer's power components. The upper and lower PCBs are connected by a stable electrical connection structure, such as... Figure 15 As shown, a 16-hole single-row straight pin header with a 2.54mm pitch can be used to achieve reliable transmission of power and control signals. This ensures the stability of power supply and command interaction for each module, and fundamentally reduces mutual interference between the lower-level power circuit and the upper-level control circuit through physical isolation.

[0074] The above description is a further detailed explanation of the present utility model in conjunction with specific embodiments, and it should not be considered that the specific implementation of the present utility model is limited to this. For those skilled in the art to which the present utility model pertains and related fields, any extensions, operation methods, and data substitutions made based on the technical solution concept of the present utility model should fall within the protection scope of the present utility model.

Claims

1. A digital display vehicle air conditioning controller, characterized in that, It includes an MCU control module, a power supply module, a sensor acquisition module, an air conditioning load drive module, an isolation detection module, a button control module, a button backlight module, and a digital display drive module; The MCU control module is electrically connected to the sensor acquisition module, the air conditioner load drive module, the isolation detection module, the button control module, the button backlight module, and the digital display drive module, respectively, and is used to receive the signals transmitted by each module and output control commands. The power module is used to receive 12V / 24V automotive power input, and after voltage processing, outputs a working voltage that is compatible with each module. The sensor acquisition module is used to acquire automotive air conditioning environment sensor signals and power supply voltage feedback signals, and transmit the acquired signals to the MCU control module after processing. The air conditioner load drive module is used to receive instructions from the MCU control module, drive the air conditioner relays and actuators to operate, and cooperate with the isolation detection module to provide feedback on the load working status. The isolation detection module is used to achieve high and low voltage signal isolation, detect the low-level active signal of the air conditioning load drive module, and transmit the detection result to the MCU control module. The button control module is used to collect the trigger signals of user operation buttons and transmit the signals to the MCU control module to execute the corresponding air conditioning control function; The button backlight module is used to adjust the brightness of the button backlight to adapt to the vehicle power status and external signal control requirements. The digital display driver module is used to receive the control signal after level conversion from the MCU control module, and drive the digital display screen to display air conditioner-related status information and fault codes.

2. The digital display vehicle air conditioning controller according to claim 1, characterized in that, The power module includes a reverse connection protection circuit, a surge protection circuit, a filter circuit, a power conversion chip, and a voltage regulator chip. The 12V / 24V automotive input power is processed sequentially by the reverse connection protection circuit, the surge protection circuit, and the filter circuit before being input to the power conversion chip. The power conversion chip converts the processed automotive power into a first operating voltage. Another path is input to the voltage regulator chip, which converts the first operating voltage into a second operating voltage.

3. The digital display vehicle air conditioning controller according to claim 2, characterized in that, The sensor acquisition module includes an environmental sensor signal acquisition sub-circuit and a power supply voltage signal acquisition sub-circuit; The environmental sensor signal acquisition sub-circuit includes sensors for acquiring vehicle interior temperature and defrosting status. Each sensor converts the acquired physical signal into an electrical signal through a resistor voltage divider, and after being processed by a current-limiting resistor, it is transmitted to the corresponding ADC pin of the MCU control module through a filter circuit. The power supply voltage signal acquisition sub-circuit acquires the operating voltage output by the power module through a resistor voltage divider sampling method, and transmits the sampled and converted voltage signal to the MCU control module after processing by a filtering circuit.

4. The digital display vehicle air conditioning controller according to claim 3, characterized in that, The air conditioner load drive module includes a relay drive sub-circuit and a prompt sound drive sub-circuit; In the relay drive sub-circuit, the relays for the evaporator fan, compressor, and generator load all adopt a low-side control mode, which is controlled by a drive chip. The input terminal of the drive chip is connected to the IO port of the MCU control module, and the output terminal is grounded. When the MCU control module outputs a control signal, it triggers the drive chip to conduct, thereby controlling the corresponding relay to operate. Each relay is connected in parallel with a freewheeling protection element to suppress the back electromotive force generated when the relay is disconnected. The prompt tone driver sub-circuit is integrated into the idle channel of the driver chip and is used for fault alarms and operation prompts.

5. The digital display vehicle air conditioning controller according to claim 4, characterized in that, The isolation detection module uses an isolation element as its core and employs a low-side effective detection method. The primary side of the isolation element is connected to the vehicle power supply via a current-limiting resistor, and the negative terminal of the primary side is connected in series with a reverse connection protection element before being connected to the relay load signal terminal to be tested. The secondary side of the isolation element is connected to the operating voltage, and the output terminal of the secondary side is connected to the IO pin of the MCU control module via a filter circuit. When a low-level signal is detected on the primary side, the isolation element is turned on and outputs a corresponding signal to the MCU control module, thereby realizing the isolation detection of high and low voltage signals.

6. The digital display vehicle air conditioning controller according to claim 5, characterized in that, The button control module adopts an independent button structure, including multiple tactile switches. One end of each tactile switch is grounded, and the other end is connected to the corresponding IO pin of the MCU control module via a pull-up resistor. When the user triggers the button, the level of the corresponding IO pin changes, and the MCU control module recognizes this and executes the corresponding air conditioning control function.

7. The digital display vehicle air conditioning controller according to claim 6, characterized in that, The button backlight module includes multiple button backlight adjustment sub-circuits, powered by an isolated power supply. The light source of each button backlight adjustment sub-circuit is a light-emitting element corresponding to each button, and the light-emitting element is connected to the isolated power supply through a switching element. When there is no input from the vehicle power supply, an external control signal controls the button backlight to be fully lit. When there is input from the vehicle power supply, the MCU control module adjusts the conduction degree of the switching element through an output control signal to adjust the brightness of the button backlight. At the same time, the backlight brightness can be compensated by the signal provided by the vehicle power supply.

8. The digital display vehicle air conditioning controller according to claim 7, characterized in that, The digital display driving module includes a level conversion sub-circuit and a display driving sub-circuit; The level conversion sub-circuit uses a conversion driver device to achieve level adaptation between the MCU control module and the display driver sub-circuit; The display driver sub-circuit uses a driver chip and a shift register, which work together to drive the digital display screen to show the air conditioner status, fault codes, and power parameters.

9. The digital display vehicle air conditioning controller according to claim 8, characterized in that, It adopts a double-layer PCB design, in which: The lower PCB board houses the power components for the power supply module and the air conditioning load drive module; The upper PCB board houses the control circuitry for the MCU control module, sensor acquisition module, isolation detection module, button control module, button backlight module, and digital display driver module. The upper and lower PCB boards are connected by an electrical connection structure to transmit power and control signals, while physical isolation reduces mutual interference between circuits.

10. The digital display vehicle air conditioning controller according to claim 9, characterized in that, The MCU control module includes a microcontroller unit and peripheral circuits. The microcontroller unit is a GD32E230 microcontroller, and the peripheral circuits include a crystal oscillator circuit, a reset circuit, and a configuration circuit.

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