Automobile air conditioner multifunction controller

Abstract

The application discloses a multifunctional controller for an automobile air conditioner, comprising an MCU, a power module, a collection circuit, a driving control circuit, a backlight adjusting circuit, a level conversion circuit, an LCD display driving circuit and a key collection circuit; the circuit is simplified, discrete elements are reduced, cost is lowered and reliability is improved through a multi-channel integrated driving chip; five kinds of key sensors and voltage collection functions are integrated, comprehensive data support is provided for the MCU, precise temperature control of the air conditioner is realized; the starting power supply enable circuit is used for controlling the start and stop of the power supply chip, static power consumption is greatly reduced, and the service life of the vehicle machine battery is prolonged; the display screen and the key backlight support multi-mode adjustment and PWM fine-tuning, visual clarity and energy-saving requirements are considered, and user experience is optimized; meanwhile, the state of the actuator and the blower is monitored in real time, fault codes are generated and displayed when an abnormality occurs, and the maintenance efficiency is improved through rapid fault positioning.

Description

Technical Field

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

[0002] With the development of automotive electronics technology, automotive air conditioning systems have evolved from simple temperature regulation functions to intelligent and integrated systems. However, existing vehicle air conditioning control assemblies still have many technical defects, making it difficult to meet the current automotive users' needs for air conditioning control precision, ease of use, and low power consumption. Specifically, the shortcomings of existing technologies are mainly reflected in the following aspects: First, the integration is low, and the control circuits mostly adopt a distributed design with complex peripheral circuits, which not only increases manufacturing costs but also makes fault location difficult and maintenance inefficient during subsequent repairs. Second, there are few reserved external signal acquisition interfaces, which can usually only acquire a small number of key temperature signals (such as the interior temperature of the vehicle) and cannot comprehensively acquire multi-dimensional parameters such as engine water tank temperature, exterior temperature, sunlight intensity, and defrosting status. Consequently, it is impossible to accurately describe the temperature status of the main components of the vehicle system, affecting the accuracy of the air conditioning control strategy. Third, the control precision of external actuators is insufficient, and there is a lack of effective fault detection mechanisms. When external circuits (such as actuators and relays) malfunction, it is impossible to quickly locate the fault point, resulting in long repair times. Fourth, the power consumption control design is unreasonable. Most products directly draw power from the vehicle battery, and there is still static power consumption even when the vehicle is turned off. Long-term use can easily cause the vehicle battery to deplete, affecting the battery life.

[0003] In view of the shortcomings of the existing technology, there is an urgent need to develop an automotive air conditioning controller with high integration, comprehensive signal acquisition, high control precision, low power consumption and fault detection function, so as to solve the technical pain points of the existing products. Utility Model Content

[0004] 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 multi-functional controller for automotive air conditioning.

[0005] The technical solution is: a multi-functional controller for automotive air conditioning, including an MCU, a power module, a data acquisition circuit, a drive control circuit, a backlight adjustment circuit, a level conversion circuit, an LCD display drive circuit, and a key acquisition circuit;

[0006] The MCU is electrically connected to the acquisition circuit, drive control circuit, backlight adjustment circuit, level conversion circuit, LCD display drive circuit, and key acquisition circuit, respectively, and is used to receive signals transmitted by each circuit and output control commands.

[0007] The power module is used to receive the vehicle's ignition voltage, process the voltage, output the working voltage adapted to each circuit, and control the circuit to start and stop through the ignition enable logic.

[0008] The acquisition circuit is used to acquire sensor signals and voltage feedback signals related to the automotive air conditioning system, and transmit the acquired signals to the MCU.

[0009] The drive control circuit is used to receive MCU instructions, drive the air conditioner-related relays and actuators to operate, and detect the working status of the blower.

[0010] The backlight adjustment circuit is used to adjust the brightness of the display screen backlight and the button backlight respectively, to adapt to the vehicle's ignition status and external signal control requirements.

[0011] The level conversion circuit is used to adapt to the level difference between the MCU and the LCD display driver circuit, so as to realize the normal transmission of signals between the two.

[0012] The LCD display driving circuit is used to receive the control signal from the MCU after level conversion, and drive the LCD screen to display air conditioner-related status information.

[0013] The key acquisition circuit is used to acquire the trigger signals of user operation keys and transmit the signals to the MCU to execute the corresponding air conditioning control function.

[0014] Preferably, the power module includes a reverse connection protection circuit, a TVS circuit, an LC filter circuit, an ignition power enable circuit, a power conversion chip, and an LDO chip.

[0015] The vehicle's ignition voltage is processed sequentially by the reverse connection protection circuit, TVS circuit, and LC filter circuit before being input to the power conversion chip. The ignition power enable circuit is connected to the enable terminal of the power conversion chip, and the power conversion chip is triggered to start working only when the vehicle's ignition signal is present.

[0016] The power conversion chip converts the processed vehicle voltage into a first operating voltage. The first operating voltage is divided into two paths: one path is supplied to the subsequent LCD display driver circuit and backlight adjustment circuit through an LC filter circuit and a TVS circuit; the other path is input to an LDO chip. The LDO chip has an ESD electrostatic protection structure at both its input and output terminals, which converts the first operating voltage into a second operating voltage. The second operating voltage is used to power the MCU, acquisition circuit, and drive control circuit.

[0017] Preferably, the acquisition circuit includes a sensor signal acquisition sub-circuit and a voltage signal acquisition sub-circuit;

[0018] The sensor signal acquisition sub-circuit includes sensors for acquiring engine water tank temperature, outside temperature, inside temperature, defrosting status, and sunlight intensity. Each sensor converts the acquired physical signal into an electrical signal through a resistor voltage divider, and transmits it to the corresponding pin of the MCU after current limiting.

[0019] The voltage signal acquisition sub-circuit acquires the feedback voltage of the mode actuator, the feedback voltage of the hybrid actuator, and 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.

[0020] Preferably, the drive control circuit includes a relay drive sub-circuit, an actuator drive sub-circuit, and a blower detection sub-circuit;

[0021] In the relay driver sub-circuit, the A / C relay and the FAN high-speed relay adopt a low-side control mode, which is controlled by the first driver chip. The input terminal of the first driver chip is connected to the MCU, and the output terminal is grounded. When the MCU outputs a high level, it triggers the first driver chip to conduct, thereby controlling the corresponding relay to operate. The subsequent defrost relay adopts a high-side drive mode, which is controlled by the second driver chip. When the MCU outputs a high level, it triggers the second driver chip to output a power signal, thereby controlling the subsequent defrost relay to operate.

[0022] The actuator drive sub-circuit uses a third drive chip, which has multiple half-bridge drive channels and can be configured to a full-bridge drive mode. It drives the mode actuator, the heating and cooling actuator, and the fresh air actuator through different channels, and detects the limit position signals of the mode actuator and the heating and cooling actuator.

[0023] The blower detection sub-circuit includes an inverting amplifier subtractor and a comparator. The inverting amplifier subtractor processes the blower feedback voltage and the blower supply voltage, and subtracts them by a fixed ratio to obtain the proportional voltage of the blower operating voltage. The comparator compares the proportional voltage with the reference voltage output by the MCU and outputs high and low level signals to determine whether the blower is working.

[0024] Preferably, the backlight adjustment circuit includes a display screen backlight adjustment sub-circuit and a button backlight adjustment sub-circuit;

[0025] In the display screen backlight adjustment sub-circuit, the positive terminal of the display screen backlight is connected to the first working voltage, the negative terminal is connected to the collector of the first transistor, the emitter of the first transistor is grounded, and the base is connected to a designated pin of the MCU through a voltage divider and filter circuit. The MCU controls the conduction degree of the first transistor by outputting a PWM wave, thereby adjusting the brightness of the display screen backlight.

[0026] The button backlight adjustment sub-circuit has two control modes: When the vehicle system has no ignition signal, the external control signal controls the button backlight to be fully lit through the second transistor. The collector of the second transistor is connected to the negative terminal of the button backlight, the emitter is grounded, and the base is connected to the external control signal through a voltage divider circuit. When the vehicle system has an ignition signal, the MCU outputs a high level to trigger the third transistor to conduct. The collector of the third transistor is connected to the base of the second transistor, and the emitter is grounded to close the control path of the second transistor. At this time, the MCU controls the brightness of the button backlight through a fourth transistor. The collector of the fourth transistor is connected to the negative terminal of the button backlight, the emitter is grounded, and the base is connected to a designated pin of the MCU through a voltage divider circuit. At the same time, the vehicle system provides a PWM signal to the button backlight adjustment sub-circuit for fine adjustment of the backlight brightness.

[0027] Preferably, the level conversion circuit uses a fifth transistor and a sixth transistor as conversion driving devices;

[0028] The MCU's control terminal is connected to the emitter of the fifth and sixth transistors. The base of the fifth and sixth transistors is connected to a -3.3V power supply, keeping the transistors in a normally on state. The first operating voltage is connected to the collector of the fifth and sixth transistors. The two control pins of the LCD display driver circuit are connected to the collectors of the fifth and sixth transistors, respectively.

[0029] Preferably, the LCD display driving circuit uses a fourth driving chip, which is connected to the MCU through a level conversion circuit, and its output pin is directly connected to the LCD segment screen.

[0030] Preferably, the button acquisition circuit adopts a matrix button structure, including air volume increase / decrease buttons, temperature increase / decrease buttons, A / C button, MODE button, AUTO button, front defrost button, OUTTEMP button, rear defrost button, OFF button, internal / external circulation switch button, and ECON energy-saving mode button.

[0031] Preferably, in the power module, the vehicle battery power supply is connected to the common-mode inductor through a first diode, and the vehicle ignition power supply is connected to the common-mode inductor through a second diode, together forming a 12V input terminal; the common-mode inductor is subsequently connected to an isolation filter circuit composed of multiple capacitors to convert the input voltage into a stable 12V voltage.

[0032] Preferably, in the third driving chip of the actuator driving sub-circuit, the first set of channels is used to detect the limit position signals of the mode actuator and the heating / cooling actuator, the second set of channels is used to drive the mode actuator, the third set of channels is used to drive the fresh air actuator, and the fourth set of channels is used to drive the heating / cooling actuator; the third driving chip is connected to the MCU via SPI communication, receives the control signals output by the MCU, and feeds back the actuator status signals.

[0033] Through the above technical solutions, the beneficial effects of this utility model are as follows: The multi-functional controller for automotive air conditioning in this application simplifies the circuit and reduces discrete components through multi-channel integrated drive chips, thereby reducing costs and improving reliability; it integrates five types of key sensors and voltage acquisition functions to provide comprehensive data support for the MCU, enabling precise temperature control of the air conditioning; it controls the start and stop of the power chip by using the ignition power enable circuit, significantly reducing static power consumption to extend the life of the vehicle's battery; the backlight of the display screen and buttons supports multi-mode adjustment and fine-tuning of PWM, taking into account both visual clarity and energy-saving requirements, and optimizing the user experience; at the same time, by monitoring the status of the actuator and blower in real time, it generates and displays fault codes when abnormalities occur, quickly locating faults and improving maintenance efficiency. Attached Figure Description

[0034] Figure 1 This is a system module structure diagram of this utility model.

[0035] Figure 2 This is a schematic diagram of the MCU peripheral interface circuit according to an embodiment of the present invention.

[0036] Figure 3 This is a schematic diagram of a power supply circuit according to an embodiment of the present invention.

[0037] Figure 4 This is a schematic diagram of the acquisition circuit according to an embodiment of the present invention.

[0038] Figure 5 This is a schematic diagram of the backlight adjustment sub-circuit of a display screen according to an embodiment of the present invention.

[0039] Figure 6 This is a schematic diagram of the button backlight adjustment sub-circuit of one embodiment of the present invention.

[0040] Figure 7 This is a schematic diagram of an LCD display driving circuit according to an embodiment of the present invention.

[0041] Figure 8 This is a schematic diagram of a level conversion circuit according to an embodiment of the present invention.

[0042] Figure 9 This is a schematic diagram of a key acquisition circuit according to an embodiment of the present invention.

[0043] Figure 10 This is a schematic diagram of a relay driver sub-circuit according to an embodiment of the present invention.

[0044] Figure 11 This is a schematic diagram of the actuator drive sub-circuit of one embodiment of the present invention.

[0045] Figure 12This is a schematic diagram of the blower detection sub-circuit of one embodiment of the present invention.

[0046] Figure 13 This is a schematic diagram of the drive circuit for a fresh air actuator according to an embodiment of the present invention. 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 13 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 multi-functional controller for automotive air conditioning of the present invention uses a microcontroller unit (MCU, model GD32E230C8T6) as the core control module. It achieves signal interaction with various functional circuits through electrical connections. The overall system includes a power supply circuit, a data acquisition circuit, a drive control circuit, a backlight adjustment circuit, a level conversion circuit, an LCD display drive circuit, and a button data acquisition circuit. All circuits work together to complete the comprehensive control of the air conditioning. The specific technical solution is as follows:

[0050] like Figure 2 As shown, the MCU, as the core of the controller, establishes electrical connections with the data acquisition circuit, drive control circuit, backlight adjustment circuit, level conversion circuit, LCD display drive circuit, and key acquisition circuit. Its main functions include: receiving sensor signals and voltage feedback signals transmitted by the data acquisition circuit, processing the signals to generate control commands; outputting commands to the drive control circuit to drive relays and actuators; outputting PWM signals to the backlight adjustment circuit to adjust the backlight brightness; interacting with the LCD display drive circuit through the level conversion circuit to control the screen display content; receiving trigger signals from the key acquisition circuit to execute corresponding air conditioning control functions; and possessing fault detection and code generation capabilities. When an external device malfunctions, it generates a corresponding fault code and controls the LCD screen display.

[0051] like Figure 3As shown, the power supply circuit provides a stable operating voltage for the entire controller and achieves low-power control through the ignition enable logic. Its specific structure and working principle are as follows: After receiving the 12V ignition voltage from the vehicle's infotainment system, the circuit first uses a reverse connection protection circuit composed of diodes D1 and D2 to prevent reverse connection from damaging components. Then, it uses a TVS diode to suppress transient voltage to avoid voltage spikes. Subsequently, the voltage enters an LC filter circuit composed of a common-mode inductor L1 and capacitors C67, C68, C69, C5, and C102. The fluctuating 12V voltage is converted into a stable input voltage after being processed by this circuit, and finally input to the power conversion chip SA21345AFCA.

[0052] To achieve low-power control, the power supply circuit also includes an ignition power enable circuit. The ignition power supply IGN passes sequentially through diode D3, current-limiting resistor R121, TVS diode, voltage divider resistor R120, and protection diode before connecting to the base of transistor QQ1. The collector of transistor QQ1 is connected to a 12V power supply, while the emitter is connected to the enable pin of the power conversion chip SA21345AFCA via a voltage divider circuit. An ESD diode is also installed on this enable pin for electrostatic discharge protection. Transistor QQ1 conducts only when the vehicle's infotainment system generates an ignition signal, providing a valid voltage to the enable pin and activating the power conversion chip SA21345AFCA. If there is no ignition signal, transistor QQ1 is cut off, the power conversion chip SA21345AFCA is turned off, and the power supply to subsequent stages is disconnected, significantly reducing the controller's standby power consumption.

[0053] The power conversion chip SA21345AFCA converts the input 12V voltage to 5V voltage. This 5V voltage serves as the first operating voltage and is divided into two outputs: one output, after being processed by an LC filter circuit and a TVS circuit, supplies power to the LCD display driver circuit and the backlight adjustment circuit, respectively, providing stable power to these two circuits; the other output is connected to the LDO chip REG1117-3.3. The input and output terminals of the LDO chip REG1117-3.3 are equipped with ESD electrostatic protection structures, which can convert the input 5V voltage to 3.3V voltage. This 3.3V voltage serves as the second operating voltage, supplying power to the MCU, the acquisition circuit, and the drive control circuit.

[0054] In addition, the ADJ terminal of the power conversion chip SA21345AFCA is connected to a voltage divider signal. One end of this voltage divider signal is connected to the 5V output terminal, and the other end is grounded. When the 5V output voltage fluctuates, the voltage divider signal acquired by the ADJ terminal will change synchronously. The power conversion chip SA21345AFCA will then fine-tune the 5V output voltage in real time according to this changing voltage divider signal to ensure that the 5V output voltage remains stable. The output terminal of the LDO chip REG1117-3.3 is also equipped with a filter circuit consisting of capacitors C1, C6, and C2, as well as Z18 ESD protection devices and DD2 TVS protection devices. These structures further filter noise in the 3.3V output voltage, resist electrostatic discharge and transient voltage surges, ensure the stability of the 3.3V operating voltage, and provide a guarantee for the reliable operation of subsequent circuits.

[0055] The data acquisition circuit is used to comprehensively collect the status signals of the air conditioning system, providing data support for MCU control. It is divided into sensor signal acquisition sub-circuit and voltage signal acquisition sub-circuit.

[0056] like Figure 4 As shown, the sensor signal acquisition subcircuit includes five key sensors responsible for collecting data on engine coolant temperature, outside vehicle temperature, inside vehicle temperature, defrost status, and sunlight intensity. Each sensor converts its physical signal into an electrical signal using a resistor divider, which is then current-limited before being transmitted to the corresponding pin of the MCU. Specifically, the sunlight sensor transmits its signal to the MCU's PA-0 pin via a voltage divider between resistors R82 and R35; the coolant temperature sensor transmits its signal to the PA-4 pin via a voltage divider between resistors R79 and current-limited resistor R36; the outside temperature sensor transmits its signal to the PA-3 pin via a voltage divider between resistors R77 and current-limited resistor R84; the inside vehicle temperature sensor transmits its signal to the PA-2 pin via a voltage divider between resistors R65 and current-limited resistor R34; and the defrost sensor transmits its signal to the PA-1 pin via a voltage divider between resistors R78 and current-limited resistor R85.

[0057] The voltage signal acquisition sub-circuit uses a resistor divider sampling method to acquire the feedback voltage of the mode actuator, the feedback voltage of the hybrid actuator, and the operating voltage output by the power supply circuit. The sampled and converted voltage signals are transmitted to the MCU for the MCU to determine the actuator's operating status and power supply stability.

[0058] The backlight adjustment circuit is used to intelligently adjust the backlight of the display screen and the backlight of the buttons according to the vehicle system status and user needs. It is divided into a display screen backlight adjustment sub-circuit and a button backlight adjustment sub-circuit.

[0059] like Figure 5As shown, in the display backlight adjustment sub-circuit, the positive terminal of the display backlight is connected to a 5V power supply. After filtering by capacitors C55 and C56, the power supply is ensured to be stable. The negative terminal of the backlight is connected to the collector of transistor Q2. The emitter of Q2 is grounded, and the base is connected to the PA10 pin of the MCU through a voltage divider circuit composed of R74 and R75 and a filter circuit composed of C57 and C58. The MCU controls the conduction level of Q2 by outputting a PWM wave, thereby adjusting the brightness of the display backlight.

[0060] like Figure 6 As shown, the button backlight adjustment sub-circuit has two control modes to adapt to the vehicle's ignition status. When the vehicle's ignition system has no ignition signal, the button backlight is controlled by an external signal. The external input signal passes through diode DD4, an LED, and a current-limiting resistor, and then is connected to the base of transistor Q5 via a voltage divider through R90 and R72. The collector of Q5 is connected to the negative terminal of the button backlight, and the emitter is grounded. At this time, Q5 is turned on, and the button backlight is fully lit, making it convenient for users to operate when the vehicle is off. When the vehicle's ignition system has an ignition signal, the MCU's PC15 pin outputs a high level, which is connected to the base of transistor Q11 via a voltage divider through R102 and R103. The collector of Q11 is connected to the base of Q5, and the emitter is grounded. When Q11 is turned on, it pulls the base voltage of Q5 low, turning Q5 off. At this time, the button backlight is controlled by transistor Q10. The collector of Q10 is connected to the negative terminal of the button backlight, and the base is connected to the PB0 pin of the MCU through a voltage divider circuit composed of R144 and R139. The MCU controls the conduction state of Q10 through an output signal to adjust the brightness of the button backlight. In addition, the vehicle system also provides a PWM signal KEYLIGHT-PWM-IN connected to this sub-circuit for fine-tuning of the backlight brightness, improving the user's visual experience.

[0061] Meanwhile, the backlight adjustment circuit also includes a backlight detection sub-circuit. The external button backlight power supply is connected to the base of transistor Q1 via a voltage divider circuit composed of DD4, DD3, R3, and R4, and then to the emitter of Q1 via R134. The collector of Q1 is grounded, and its collector is connected to a 5V power supply via R1 and to the PB5 pin of the MCU via R2. When the external button backlight power supply is working, Q1 is turned on, and the PB5 pin of the MCU is at a low level; when the external power supply is not working, Q1 is turned off, and the PB5 pin is at a high level. The MCU adapts to the external backlight power supply status by detecting the level of this pin.

[0062] In practical implementation, since the MCU operates at 3.3V and the LCD display driver chip BU91797muf-me operates at 5V, a level conversion circuit is required to ensure normal signal transmission between the two. Figure 7 As shown, the circuit uses transistors Q4 and Q6 as switching drivers.

[0063] The MCU's control pins, namely the SPI communication data and clock lines, are connected to the emitters of Q4 and Q6, respectively. The MCU's -3.3V power supply is connected to the base of the transistor, keeping the transistor in a normally-on state. The 5V power supply is connected to the collector of the transistor through a 3.3K resistor. The LCD display driver chip's control pins, namely LCD_DATA and LCD_SCLK, are connected to the collector of the transistor through a 1K resistor.

[0064] When the MCU control terminal outputs a low level, the transistor collector voltage is pulled down to 0V, and the LCD driver chip control pin level is synchronously 0V; when the MCU control terminal outputs a high level, the transistor collector voltage is equal to 5V, and the driver chip control pin level is synchronously 5V. This process achieves the adaptation between 3.3V and 5V levels, ensuring stable SPI communication.

[0065] The LCD display driver circuit receives MCU instructions and drives the LCD segment display to show air conditioner status information. Its core is the driver chip BU91797muf-me. Figure 8 As shown, the chip establishes an SPI communication connection with the MCU's PB8 and PB6 pins through a level conversion circuit to receive control signals transmitted by the MCU. The chip's output pins are directly connected to the LCD segment display. Complete screen control is achieved through four COM ports (COM00, COM11, COM22, COM33) and twelve independent pins (SEG00 to SEG011). To illuminate a specific segment, simply apply a high level to the corresponding COM port and a low level to the corresponding independent pin.

[0066] To ensure display stability, an LC filter circuit consisting of ferrite beads L24 to L37 is installed between the LCD display driver circuit and the screen to filter the drive signal. Furthermore, each screen driver pin is equipped with an ESD protection device such as SMBJ12CA to prevent electrostatic damage to the screen. In addition, the chip's power supply is connected to a 5V power supply, which is filtered to ensure stable power supply and reliable chip operation.

[0067] The keypad acquisition circuit uses a matrix keypad structure to acquire user operation commands, such as... Figure 9 As shown, it includes 11 function buttons: fan speed increase / decrease button, temperature increase / decrease button, A / C button, MODE button, AUTO button, front defrost button, OUTTEMP temperature display button, rear defrost button, OFF button, internal / external circulation switch button, and ECON energy-saving mode button.

[0068] The trigger signals of each button are transmitted to the MCU through a matrix circuit. The MCU detects the status of each button in real time and outputs corresponding control commands according to the function of different buttons. When the fan speed button is pressed, the MCU outputs a control signal to pin U2-3 of the blower detection sub-circuit via pin PB9. This control signal is compared with the collected feedback voltage (connected to pin U2-2), and the fan speed is adjusted by outputting a signal from pin U2-1. Simultaneously, the MCU also outputs a signal to the VNLD5300-E chip to drive the blower high-speed relay. When the A / C button or rear defrost button is pressed, the MCU outputs drive signals to the VNLD5300-E chip and the ITS4140 chip respectively, controlling the A / C relay and rear defrost relay respectively. When the front defrost button, temperature increase / decrease button, AUTO button, or ECON energy-saving mode button is detected, the MCU adjusts the output of the heating / cooling actuator to ensure the vehicle's air conditioning operation matches the set state. When the MODE button or internal / external air circulation button is detected, the MCU outputs an SPI signal to the BD16938AEFV-C chip, which drives the mode actuator or fresh air actuator to switch air conditioning modes.

[0069] The drive control circuit receives instructions from the MCU to drive and detect the status of external actuators of the air conditioner, including a relay drive sub-circuit, an actuator drive sub-circuit, and a blower detection sub-circuit.

[0070] Among them, such as Figure 10 As shown, the relay driver sub-circuit employs differentiated driving methods for different relays. The A / C relay and FAN high-speed relay use low-side control, implemented through the driver chip VNLD5300-E. The input of this chip is connected to the MCU, and its output is grounded. When the MCU control pin outputs a high level, VNLD5300-E conducts, and its output is low, triggering the relay. The subsequent defrost relay uses high-side driving, controlled by the driver chip ITS4140. When the corresponding pin of the MCU outputs a high level, the ITS4140 outputs a power signal, driving the relay to operate.

[0071] like Figure 11 and 13As shown, the actuator drive sub-circuit uses the BD16938AEFV-C driver chip. This chip has eight half-bridge drive channels, which can be configured as four full-bridge drives. Different channels are used to drive and detect the status of various actuators. Specifically, OUT1 and OUT2 channels are used to detect the limit position signals of the mode actuator and the heating / cooling actuator, respectively; OUT3 and OUT4 channels drive the mode actuator; OUT5 and OUT6 channels drive the fresh air actuator; and OUT7 and OUT8 channels drive the heating / cooling actuator. The BD16938AEFV-C connects to the MCU via SPI communication. The SDI pin receives control signals from the MCU, the SDO pin provides feedback on the actuator status signal, and the EN pin is used to enable the control chip.

[0072] The blower detection subcircuit consists of an inverting amplifier subtractor and a comparator. The input terminals are connected to the blower power supply voltage and the blower feedback voltage. In practice, the inverting amplifier subtractor and comparator can be integrated using an LM2904 low-power dual-channel operational amplifier U2. Figure 12 As shown, pins 1, 2, and 3 of U2 form an inverting amplifier structure, processing the two voltages and subtracting them by a fixed ratio to obtain the proportional voltage of the blower's operating voltage. This proportional voltage is input to pin 5 of U2, and pin 6 of U2 is connected to the reference voltage output by the MCU. After comparison, the result is output from pin 7 of U2. If the proportional voltage is greater than the reference voltage, pin 7 of U2 outputs a low level, indicating that the blower is not working; if the proportional voltage is less than or equal to the reference voltage, it outputs a high level, indicating that the blower is working normally. This result is transmitted to the MCU for blower status monitoring and speed regulation.

[0073] In practical operation, when the user starts the vehicle, the vehicle's infotainment system generates a 12V ignition signal. This signal is processed sequentially by a reverse polarity protection diode D1, a common-mode inductor L1, and an LC filter circuit before being input to the power conversion chip SA21345AFCA. Simultaneously, the ignition power supply IGN is divided by diode D3, current-limiting resistor R121, a TVS diode, and voltage-dividing resistor R120, triggering transistor QQ1 to conduct. The enable pin of the power conversion chip SA21345AFCA receives a valid voltage, and the chip then starts up, converting the 12V voltage to 5V. The converted 5V voltage is output in two paths: one path supplies power to the LCD display driver circuit and the backlight adjustment circuit; the other path is converted to 3.3V by the LDO chip REG1117-3.3 to power the MCU, acquisition circuit, and drive control circuit. At this point, the entire controller enters its operational state. If the vehicle is turned off, the ignition signal of the vehicle's infotainment system disappears, transistor QQ1 is cut off, the power conversion chip SA21345AFCA is turned off, the power supply to the subsequent circuits is cut off, and the controller enters a low-power standby state.

[0074] Once the controller enters the working state, the data acquisition circuit begins operation. The sunlight sensor, water temperature sensor, outside temperature sensor, in-vehicle temperature sensor, and defrost sensor each acquire their corresponding physical quantities. The acquired signals are first processed by voltage division and current limiting before being transmitted to the PA0 to PA4 pins of the MCU. The voltage signal acquisition sub-circuit acquires the feedback voltage of the mode actuator, the feedback voltage of the hybrid actuator, and the 5V and 3.3V operating voltages output from the power supply circuit. These acquired voltage signals are transmitted to the analog input pins of the MCU. After receiving these signals, the MCU performs AD conversion and arithmetic processing to generate the current status data of the air conditioner and determines whether the control strategy needs to be adjusted based on the data.

[0075] The MCU transmits the generated air conditioning status data to the LCD display driver chip BU91797muf-me via SPI communication and a level conversion circuit. After receiving the data, the chip drives the LCD segment display to show information such as the interior temperature, exterior temperature, fan speed, and air conditioning mode. Simultaneously, the MCU adjusts the backlight according to the vehicle's ignition status: when the vehicle has an ignition signal, the MCU outputs a PWM wave through the PA10 pin to control transistor Q2, thereby adjusting the display backlight brightness; it also outputs a signal through the PC15 pin to trigger transistor Q11 to conduct, turning off transistor Q5, and then controls transistor Q10 through the PB0 pin to adjust the button backlight brightness, further fine-tuning the backlight brightness in conjunction with the PWM signal provided by the vehicle. When there is no ignition signal, transistor Q5 conducts, the button backlight remains fully lit, and the display backlight adjusts to a low-brightness mode based on external signals.

[0076] When a user presses a function button in the button acquisition circuit, such as the A / C button, the matrix circuit transmits the button's trigger signal to the MCU. The MCU then identifies the button's function and outputs the corresponding control command. If the user presses the A / C button, the MCU outputs a high level to the driver chip VNLD5300-E, which turns on and controls the A / C relay, causing the air conditioning compressor to start. If the user presses the temperature increase button, the MCU outputs an SPI signal to the actuator driver chip BD16938AEFV-C, which drives the heating / cooling actuator through channels OUT7 and OUT8 to increase the vehicle's interior temperature. If the user presses the fan speed increase button, the MCU outputs a signal through the PB9 pin to adjust the blower speed, while simultaneously receiving feedback signals from U2 in the blower detection sub-circuit to ensure the blower speed remains stable at the set value.

[0077] The MCU receives actuator status signals, such as the actuator's limit position signals, from the BD16938AEFV-C chip in the actuator driver sub-circuit in real time. If the actuator is detected to be stuck or experiencing other abnormalities, the MCU generates a corresponding fault code, such as "E01" to represent a mode actuator fault, and controls the LCD screen to display the fault code. Simultaneously, U2 in the blower detection sub-circuit compares the blower's operating voltage with the reference voltage in real time. If U2 outputs a low level, it indicates a blower fault, and the MCU displays this fault information on the LCD screen to remind the user to perform timely repairs.

[0078] Through the complete workflow described above, the multi-functional automotive air conditioning controller of the present invention achieves integrated, precise, and low-power control of automotive air conditioning, effectively solving the defects of low integration, insufficient control precision, and high power consumption in the prior art, and has high practicality and promotion value.

[0079] 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 multi-functional controller for automotive air conditioning, characterized in that, It includes an MCU, a power module, a data acquisition circuit, a drive control circuit, a backlight adjustment circuit, a level conversion circuit, an LCD display drive circuit, and a key acquisition circuit; The MCU is electrically connected to the acquisition circuit, drive control circuit, backlight adjustment circuit, level conversion circuit, LCD display drive circuit, and key acquisition circuit, respectively, and is used to receive signals transmitted by each circuit and output control commands. The power module is used to receive the vehicle's ignition voltage, process the voltage, output the working voltage adapted to each circuit, and control the circuit to start and stop through the ignition enable logic. The acquisition circuit is used to acquire sensor signals and voltage feedback signals related to the automotive air conditioning system, and transmit the acquired signals to the MCU. The drive control circuit is used to receive MCU instructions, drive the air conditioner-related relays and actuators to operate, and detect the working status of the blower. The backlight adjustment circuit is used to adjust the brightness of the display screen backlight and the button backlight respectively, to adapt to the vehicle's ignition status and external signal control requirements. The level conversion circuit is used to adapt to the level difference between the MCU and the LCD display driver circuit, so as to realize the normal transmission of signals between the two. The LCD display driving circuit is used to receive the control signal from the MCU after level conversion, and drive the LCD screen to display air conditioner-related status information. The key acquisition circuit is used to acquire the trigger signals of user operation keys and transmit the signals to the MCU to execute the corresponding air conditioning control function.

2. The automotive air conditioning multi-functional controller according to claim 1, characterized in that, The power module includes a reverse connection protection circuit, a TVS circuit, an LC filter circuit, an ignition power enable circuit, a power conversion chip, and an LDO chip. The vehicle's ignition voltage is processed sequentially by the reverse connection protection circuit, TVS circuit, and LC filter circuit before being input to the power conversion chip. The ignition power enable circuit is connected to the enable terminal of the power conversion chip, and the power conversion chip is triggered to start working only when the vehicle's ignition signal is present. The power conversion chip converts the processed vehicle voltage into a first operating voltage. The first operating voltage is divided into two paths: one path is supplied to the subsequent LCD display driver circuit and backlight adjustment circuit through an LC filter circuit and a TVS circuit; the other path is input to an LDO chip. The LDO chip has an ESD electrostatic protection structure at both its input and output terminals, which converts the first operating voltage into a second operating voltage. The second operating voltage is used to power the MCU, acquisition circuit, and drive control circuit.

3. The multi-functional controller for automotive air conditioning according to claim 2, characterized in that, The acquisition circuit includes a sensor signal acquisition sub-circuit and a voltage signal acquisition sub-circuit; The sensor signal acquisition sub-circuit includes sensors for acquiring engine water tank temperature, outside temperature, inside temperature, defrosting status, and sunlight intensity. Each sensor converts the acquired physical signal into an electrical signal through a resistor voltage divider, and transmits it to the corresponding pin of the MCU after current limiting. The voltage signal acquisition sub-circuit acquires the feedback voltage of the mode actuator, the feedback voltage of the hybrid actuator, and 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.

4. The multi-functional controller for automotive air conditioning according to claim 3, characterized in that, The drive control circuit includes a relay drive sub-circuit, an actuator drive sub-circuit, and a blower detection sub-circuit. In the relay driver sub-circuit, the A / C relay and the FAN high-speed relay adopt a low-side control mode, which is controlled by the first driver chip. The input terminal of the first driver chip is connected to the MCU, and the output terminal is grounded. When the MCU outputs a high level, it triggers the first driver chip to conduct, thereby controlling the corresponding relay to operate. The subsequent defrost relay adopts a high-side drive mode, which is controlled by the second driver chip. When the MCU outputs a high level, it triggers the second driver chip to output a power signal, thereby controlling the subsequent defrost relay to operate. The actuator drive sub-circuit uses a third drive chip, which has multiple half-bridge drive channels and can be configured to a full-bridge drive mode. It drives the mode actuator, the heating and cooling actuator, and the fresh air actuator through different channels, and detects the limit position signals of the mode actuator and the heating and cooling actuator. The blower detection sub-circuit includes an inverting amplifier subtractor and a comparator. The inverting amplifier subtractor processes the blower feedback voltage and the blower supply voltage, and subtracts them by a fixed ratio to obtain the proportional voltage of the blower operating voltage. The comparator compares the proportional voltage with the reference voltage output by the MCU and outputs high and low level signals to determine whether the blower is working.

5. The automotive air conditioning multi-functional controller according to claim 4, characterized in that, The backlight adjustment circuit includes a display screen backlight adjustment sub-circuit and a button backlight adjustment sub-circuit; In the display screen backlight adjustment sub-circuit, the positive terminal of the display screen backlight is connected to the first working voltage, the negative terminal is connected to the collector of the first transistor, the emitter of the first transistor is grounded, and the base is connected to a designated pin of the MCU through a voltage divider and filter circuit. The MCU controls the conduction degree of the first transistor by outputting a PWM wave, thereby adjusting the brightness of the display screen backlight. The button backlight adjustment sub-circuit has two control modes: When the vehicle system has no ignition signal, the external control signal controls the button backlight to be fully lit through the second transistor. The collector of the second transistor is connected to the negative terminal of the button backlight, the emitter is grounded, and the base is connected to the external control signal through a voltage divider circuit. When the vehicle system has an ignition signal, the MCU outputs a high level to trigger the third transistor to conduct. The collector of the third transistor is connected to the base of the second transistor, and the emitter is grounded to close the control path of the second transistor. At this time, the MCU controls the brightness of the button backlight through a fourth transistor. The collector of the fourth transistor is connected to the negative terminal of the button backlight, the emitter is grounded, and the base is connected to a designated pin of the MCU through a voltage divider circuit. At the same time, the vehicle system provides a PWM signal to the button backlight adjustment sub-circuit for fine adjustment of the backlight brightness.

6. The multi-functional controller for automotive air conditioning according to claim 5, characterized in that, The level conversion circuit uses the fifth transistor and the sixth transistor as conversion driving devices; The MCU's control terminal is connected to the emitter of the fifth and sixth transistors. The base of the fifth and sixth transistors is connected to a -3.3V power supply, keeping the transistors in a normally on state. The first operating voltage is connected to the collector of the fifth and sixth transistors. The two control pins of the LCD display driver circuit are connected to the collectors of the fifth and sixth transistors, respectively.

7. The automotive air conditioning multi-functional controller according to claim 6, characterized in that, The LCD display driving circuit uses a fourth driving chip, which is connected to the MCU through a level conversion circuit, and its output pin is directly connected to the LCD segment screen.

8. The automotive air conditioning multi-function controller according to claim 7, characterized in that, The button acquisition circuit adopts a matrix button structure, including air volume increase / decrease buttons, temperature increase / decrease buttons, A / C button, MODE button, AUTO button, front defrost button, OUTTEMP button, rear defrost button, OFF button, internal / external circulation switch button, and ECON energy-saving mode button.

9. The automotive air conditioning multi-function controller according to claim 8, characterized in that, In the power module, the vehicle battery power supply is connected to the common-mode inductor through the first diode, and the vehicle ignition power supply is connected to the common-mode inductor through the second diode, together forming a 12V input terminal; the common-mode inductor is subsequently connected to an isolation filter circuit composed of multiple capacitors to convert the input voltage into a stable 12V voltage.

10. The automotive air conditioning multi-function controller according to claim 9, characterized in that, In the third driving chip of the actuator driving sub-circuit, the first set of channels is used to detect the limit position signals of the mode actuator and the heating and cooling actuator, the second set of channels is used to drive the mode actuator, the third set of channels is used to drive the fresh air actuator, and the fourth set of channels is used to drive the heating and cooling actuator. The third driver chip is connected to the MCU via SPI communication, receives control signals output by the MCU, and feeds back actuator status signals.

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