[原创]ST A6986I 38V 5W汽车隔离应用转换器解决方案

ST公司的A6986I是汽车级器件,特别设计用于隔离降压拓扑.器件具有100%占空比和宽输入电压范围,满足汽车系统的冷启动和负载突降指标要求.A6986I的初级输出电压能精确地调整,而隔离的次级输出则由给定的变压器比来得出.器件不需要光耦合器,初级沉电流能力高达1.9A(即使在软起动时)允许适当的能量传输到次级边,使得跟踪到软起动的次级输出.控制回路是基于峰值电流模式架构和工作在强迫PWM模式.由变压器漏电感所产生的300ns消隐时间滤波器振荡,使得解决方案更加强健可靠.两个功率元件的逐个脉冲电流检测在初级边实现了有效的恒流保护.由于初级反向电流的限制,次级输出能保护短路事件.初级电压监视器,通过RST开路集电极输出报告了初级输出电压调整.器件还提供过压保护,可调开关频率,同步和可编程软起动.器件满足AEC-Q100 Grade 1规范,输入电压从4V到38V,8 μA IQ-SHTDWN,可调整fSW和同步.器件的RDS(on) HS = 180 mΩ, RDS(on) LS = 150 mΩ,并具有热关断特性.主要用在汽车隔离IGBT/SiC MOSFET栅极驱动电源,HEV/EV的车载充电器(OBC)以及电动牵引系统.本文介绍了A6986I主要特性,内部框图和多种应用电路,以及评估板STEVAL-A6986IVI/2主要特性,电路图和PCB设计图.

The A6986I is an automotive grade device specifically designed for the isolated

buck topology. The 100% duty cycle capability and the wide input voltage range

meet the cold crank and load dump specifications for automotive systems. The

primary output voltage can be accurately adjusted, whereas the isolated secondary

output is derived by using a given transformer ratio. No optocoupler is required. The

primary sink capability typically up to 1.9 A (even during soft-start) allows a proper

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