Air conditioning is an indispensable configuration for meeting the comfort requirements of the car. It is used for interior cooling, heating, ventilation, and a comfortable driving environment is also related to driving safety. The automatic air conditioner is more convenient than the traditional manual air conditioner, and can automatically detect and adjust according to the temperature set by the user, so that the temperature and humidity inside the vehicle are within the set range. Moreover, automatic air conditioning also helps to save energy and reduce fuel economy. Typical power supply structure for automotive air conditioners In general, automotive voltage is divided into 24 V system and 12 V system: 24 V power supply can be powered by high-power TVS (transient voltage suppressor), then by low-dropout regulator (LDO) to 5 V, Powering the motor driver; it can also be reduced to 12 V with a higher cost DC-DC buck, then from LDO to 5 V, while powering the motor driver; 12 V power supply to the microcontroller, sensor, etc. via the LDO At the same time, it directly supplies power to motor drivers such as DC/stepper motors. Figure 1. Typical power supply structure for automotive air conditioning If you use a 24 V power supply system, you need to consider high-voltage products, while taking into account thermal management, power efficiency and cost control; if you use a 12 V power supply system, you need to consider factors such as cost, quiescent current (Iq) and packaging. ON Semiconductor offers a rich lineup of LDOs for automotive air conditioning systems, including standard static power series (Iq >100 uA) such as NCV4264-2, NCV4266-2, and low static power series (Iq <100 uA) such as NCV8501 and NCV8502. Very low static power series (Iq <50 uA) such as NCV8664, NCV8660, ultra low static power series (Iq <33 uA) such as NCV8768, NCV8769, to meet the different needs of the design. ON Semiconductor also offers the voltage follower NCV8184, which provides an adjustable buffered output voltage that closely matches the reference input voltage (accuracy of ±3 mV). The device has an output current capability of 70 mA, a quiescent current of only 70 uA, and a typical voltage drop of only 0.35 V at 50 mA, in a SOIC-8 package. drive Damper actuator drive DC motor, unipolar stepper motor, bipolar stepper motor are three kinds of automotive air conditioning damper actuators Typical structure. The DC motor damper actuator includes a DC motor and a position sensor. A complete H-bridge (composed of 2 high-side switches and 2 low-side switches) is required to control the forward and reverse rotation of the motor. The position sensor can monitor the position of the damper in real time to realize closed-loop control. The control of the unipolar stepping motor only needs 4 high sides or 4 low side drives. Due to the characteristics of the stepping motor itself, the number of steps can be counted. To know the position of the damper; the bipolar stepper motor only needs two sets of coils, and its drive requires two H-bridges (composed of four high-side switches and four low-side switches) to control the two coils, and unipolar The stepper motor is similar, and the current position of the damper can be known by counting the number of steps. Figure 2. Damper actuator motor structure and drive type The DC motor damper actuator has a normal operating current of approximately 100 mA and a stall current of less than 450 mA. An H-bridge drive is required to change the direction of operation and provide a fault diagnosis report and adequate protection. ON Semiconductor's NCV77XX series fully meets these requirements and can operate in forward, reverse, braking and high impedance states. Taking the six-way half-bridge driver NCV7718 as an example, six PMOSs are used as high-side drivers, six NMOSs are used as low-side drivers, high and low sides are connected inside the chip, and H half-bridges are used as outputs to provide 0.55 A continuous drive current, and internal freewheeling is integrated. Diode, on-resistance typical and maximum values ​​are 1 and 2.25, controlled by a 16-bit SPI interface, low power consumption (maximum current consumption is only 5 Ua), providing drive state, low load protection, overcurrent, overtemperature and temperature Diagnostic reports such as warnings and integration of a range of protection features such as overvoltage/undervoltage protection, overcurrent shutdown, overtemperature protection, etc., in SSOP-24/SSOP24-EP package. In addition, depending on the output requirements, you can choose ON Semiconductor's 8-way half-bridge driver NCV7719 or 10-way half-bridge driver NCV7720. ON Semiconductor also offers a six-way half-bridge driver NCV7728 with independent diagnostics. The device has a peak current of 0.55 A. The typical and maximum on-resistance are 1 and 2, respectively. The interface is compatible with 3.3 V/5 V microcontrollers. Ultra-low static power is provided in mode, controlled by 16-bit SPI interface (baud rate is 5 MHz, compatible with daisy-chain communication), integrated with freewheel protection, overcurrent protection, open circuit detection, thermal shutdown and over temperature alarm protection characteristic. Figure 3. Typical application example for a 6-way half-bridge driver NCV7728 with independent diagnostics In the stepper motor damper actuator, each motor requires 4 drives, and the maximum operating current is less than 300 mA, which can be directly controlled or remotely controlled via the LIN bus. ON Semiconductor's unipolar stepper motor drivers for automotive air conditioners are the NCV7608 and NCV7240. The NCV7608 is an 8-channel high- and low-side configurable driver that delivers 350 mA of drive current per channel. It provides complete protection in a SOIC28 package and is AEC-Q101 certified. The NCV7420 is an 8-channel low-side driver that provides 600 mA per channel. The current, controlled by a 16-bit SPI interface, provides complete diagnostic and protection functions such as open circuit diagnostics, overload protection, and overtemperature protection. It is packaged in SSOP24 and certified to AEC-Q100. ON Semiconductor's bipolar stepper motor drivers for automotive air conditioners include the AMIS30730 and NCV70501, both of which have a drive current of 300 mA. The AMIS30730 uses a LIN interface with MCU, ROM, RAM and EEPROM; the NCV70501 uses an SPI interface.
Waterproof emergency lamp is made of waterproof material , which can be used both indoors and outdoors . Because of its high level of protection , achieve waterproof effect , so it can also be used outdoors . When the power grid suddenly cut down , the emergency lights can be activated backup battery is lit to bring you light .
Emergency Indicator Bulkhead Arrow Exit Sign,LED Emergency Exit Lighting,Fire Emergency Arrow Exit Bulkhead Jiangmen City Pengjiang District Qihui Lighting Electrical Appliances Co., Ltd , https://www.qihuilights.com
