This paper pays more attention to analyze the accidental conditions of the USB system, and the circuit can detect the overcurrent condition and realize the overcurrent protection, under voltage lockout and over temperature protection.

• 并针对usb系统工作时可能出现的意外情况 ,通过限流开关内部电路实现过流检测、过流保护、欠压锁定和过热保护功能。