With the widespread application of smart mobile devices, car USB universal serial bus chargers are necessary. Mobile phones can transmit data to the car's central control host through the USB port. Just like plugging in a USB disk, it can play music. The control host can be interconnected with the mobile phone, and the car's central control screen can be synchronized with the navigation. Iphone connected carplay, Android mobile phone connected carlife, can pass the USB IF certification, the eye diagram gain can be adjusted, and the signal can be adjusted according to the length of the wiring harness and the eye diagram requirements. The enhanced amplitude, the adjustable range is 10%-15%, which is conducive to platform adaptation and supports protocols, such as Apple 5V 2.1A/ Samsung 5V BC1.2/Type-C 5V 3A, etc. Type C has a higher transmission speed, the maximum transmission speed can reach 10Gbit/sec.