III. Application Scope of MOS Tube in Automotive Industry

The power MOSFET is chosen because it can withstand the transient high voltage phenomenon caused by load drop and system energy mutation in automotive electronic system, and its packaging is simple, mainly using TO220 and TO247 packages. At the same time, the application of electric windows, fuel injection, intermittent wipers and cruise control has gradually become the standard of most automobiles, and similar power devices are needed in the design. During this period, with the increasing popularity of motors, solenoids and fuel injectors, vehicle power MOSFET has also been growing. MOSFET devices used in automotive equipment involve a wide range of voltage, current and on-resistance. The bridge configuration of motor control equipment will use 30V and 40V breakdown voltage models, while 60V devices will be used to drive loads when sudden load unloading and sudden start-up must be controlled, and 75V technology will be used when industry standard is transferred to 42V battery system. The driving current range of automotive MOSFET is from 2A to 100A, and the on-resistance range is from 2m_to 100m_. The loads of MOSFET include motors, valves, lamps, heating components, capacitive piezoelectric components and DC/DC power supply. The switching frequency range is usually 10 kHz to 100 kHz. It must be noted that motor control is not suitable for switching frequency above 20 kHz. Other major requirements are UIS performance, working conditions at junction temperature limits (- 40 to 175 degrees, sometimes up to 200 degrees), and high reliability beyond vehicle life.

IV. Application Scope of MOS LED Driver

LED lamp driver. MOS transistors are often used in the design of LED lamps. NMOS is generally used for constant current drive of LED. Power MOSFET is different from bipolar transistors in that its gate capacitance is relatively large. The capacitor must be charged before it is turned on. When the capacitor voltage exceeds the threshold voltage (VGS-TH), the MOSFET starts to turn on. Therefore, it must be noted that the load capacity of the gate driver must be large enough to ensure that the equivalent gate capacitance (CEI) is charged within the required time of the system. The switching speed of MOSFET is closely related to the charging and discharging of its input capacitance. Although the user can not reduce the value of Cin, but can reduce the value of internal resistance Rs of the gate drive circuit signal source, thereby reducing the charge and discharge time constant of the gate circuit, accelerating the switching speed of general IC drive ability is mainly embodied here, we talk about the choice of MOSFET is the external MOSFET drive constant current IC. Of course, IC with built-in MOSFET need not be considered. Generally, the external MOSFET will be considered when the current is larger than 1A. In order to obtain larger and more flexible power capability of LED, the external MOSFET is the only choice. IC needs appropriate driving capability, and the input capacitance of MOSFET is the key parameter.

三、MOS管汽车行业应用范围
选用功率MOSFET是因为其能够耐受汽车电子系统中常遇到的掉载和系统能量突变等引起的 瞬态高压现象，且其封装简单，主要采用TO220 和 TO247封装。同时，电动车窗、燃油喷射、间歇式雨刷和巡航控制等应用已逐渐成为大多数汽车的标配，在设计中需要类似的功率器件。在这期间，随着电机、 螺线管和燃油喷射器日益普及，车用功率MOSFET也不断发展壮大。汽车设备中所用的MOSFET器件涉及广泛的电压、电流和导通电阻范围。电机控制设备桥接配置会使用30V和40V击穿电压型号；而在必须控制负载突卸和 突升启动情况的场合，会使用60V装置驱动负载；当行业标准转移至42V电池系统时，则需采用75V技术。汽车MOSFET驱动电流的范围由2A至100A以上，导通电阻的范围为2mΩ至100mΩ。MOSFET的负载包括电机、阀门、灯、加热部件、电容性压电组件和DC/DC电源。开关频率的范围通常为10kHz 至100kHz，必须注意的是，电机控制不适用开关频率在20kHz以上。其它的主要需求是UIS性能，结点温度极限下（-40度至175度，有时高达200度）的工作状况，以及超越汽车使用寿命的高可靠性。
四、MOS管LED驱动应用范围
LED 灯具的驱动。设计LED灯具的时候经常要使用MOS管，对LED恒流驱动而言，一般使用NMOS。功率MOSFET和双极型晶体管不同，它的栅极电容比较大，在导通之前要先对该电容充电，当电容电压超过阈值电压(VGS-TH)时MOSFET才开始导通。因此，设计时必须注意栅极驱动器负载能力必须足够大，以保证在系统要求的时间内完成对等效栅极电容(CEI)的充电。而MOSFET的开关速度和其输入电容的充放电有很大关系。使用者虽然无法降低Cin的值，但可以降低栅极驱动回路信号源内阻Rs的值，从而减小栅极回路 的充放电时间常数，加快开关速度一般IC驱动能力主要体现在这里，我们谈选择MOSFET是指外置MOSFET驱动恒流IC。内置MOSFET的IC当然 不用我们再考虑了，一般大于1A电流会考虑外置MOSFET.为了获得到更大、更灵活的LED功率能力，外置MOSFET是仅有的选择方式，IC需要合适 的驱动能力,MOSFET输入电容是关键的参数。