With the popularity of USB ports in new cars, it is becoming more important and cumbersome to power these ports. Their large number and location require a robust, simple and low-cost solution that provides original equipment manufacturers (OEMs) with the fastest design time and maximum functionality for end users. Since the buck converter operating on the main car battery is typically powered by a USB port, the converter must tolerate or prevent unavoidable voltage offsets or spikes in the car battery. Only higher rated buck converters can withstand higher battery voltages and continue to operate during battery voltage spikes. Because most USB ports only charge the battery of a portable device, passengers typically tolerate short power interruptions. Therefore, you can use an overvoltage protection circuit instead of a buck converter to protect the buck converter from the transient effects of higher battery voltages to withstand overvoltage. The overvoltage protection circuit disconnects the buck converter from the battery as long as the battery voltage is too high. If an overvoltage is required at the input, a circuit type with a low voltage rating device such as the TPS62130A-Q1 buck converter must be used. The automotive device can accept up to 17V and deliver 3A. High efficiency is achieved by synchronous rectification; its 3mm-3mm package is small for its power stage converters. In addition to allowing or preventing higher battery voltages, many USB ports also need to be able to adjust 5V at the USB port to meet the USB specification, even between changes in load current and corresponding variable voltage drops in the wiring in the vehicle. in this way. This cable drop compensation is especially important for those USB ports that have buck converters in the engine control unit (ECU) and the actual USB ports that are not close to the entire vehicle. The obvious advantage of placing a buck converter in an ECU is that a single printed circuit board (PCB) contains all of the electronics, rather than having multiple separate PCBs on each USB port - which saves money. The disadvantage is that cable voltage drop compensation is required for each buck converter. To overcome this shortcoming, the TPS2549-Q1 USB Port Charge Controller contains three useful functions: current-limit circuitry, protection of ports from overcurrent conditions, communication negotiation between USB devices and USB hosts, and easy cable drop reduction make up. This pin can be easily connected to any buck converter to adjust its output voltage as the current draw on the USB port changes. The TI Designs Charge Controller and Cable-Compensated Automotive USB Charging Port Power Reference Design demonstrates all the necessary features of the USB port - overvoltage protection, buck converter and USB charge controller with cable drop compensation support. Figure 1 shows the solution, small and simple. Figure 1: The PMP9765 demonstrates a complete USB port power solution with overvoltage protection and cable drop compensation A small, tested solution gives you all the necessary solutions to implement a full-featured USB port in your car. Input overvoltage protection ensures electronic components are safe, while the USB port controller implements the full functionality of the port. What else do you need to power the car's USB port? gree , https://www.greegroups.com