3.2.7.4.1 USB-B Power Switch

The USB-B Host port is equipped with a 500 mA high-side power switch for self-powered and bus-powered applications. If the client device is bus-powered, the carrier can supply a 5V, 500mA power to the client device. The USBB_EN_5V_PA27 signal controls the power switch and current limiter, the Microchip MIC2025, which in turn supplies power to a bus-powered client device. Per the USB specification, bus-powered USB 2.0 devices are limited to a maximum of 500 mA. The MIC2025 limits the current and indicates an overcurrent with the USBB_OVCUR_PD19 signal.