USB 4-port controller hub connects smartphone to infotainment system

November 10, 2014 // By Christoph Hammerschmidt
Microchip has extended its USB2 Controller Hub (UCH2) portfolio with a further automotive-grade four-port device, the USB84604. Featuring an upstream port that supports both USB2.0 and High Speed Interchip (HSIC) connectivity, the chip is designed for automotive infotainment system designs, where USB port expansion and connectivity is needed.

The chip vendor's proprietary FlexConnect technology allows for easy port reversals or “role swapping.” The USB84604's downstream port 1 is able to swap with the upstream host port, thus transferring the host capability to the product connected to the UCH2, such as smartphones and tablets. This unique capability allows for the smartphone ecosystem of software and applications to be connected to the automobile infotainment system.

The IC’s HSIC connectivity, which incorporates Microchip's proprietary Inter-Chip Connectivity technology, enables the USB84604 UCH2 connected on a circuit board to utilize the USB2.0 protocol, dramatically decreasing power consumption. This power reduction is most obvious when actively transferring data, and has been measured to be one seventh of the power consumed by a pair of traditional USB2.0 physical-layer transceivers.

The 4-port USB84604 UCH2 can attach to an upstream port as a Full Speed hub or as a Full/High Speed hub. When connected to a High Speed host, the four downstream-facing ports can operate at Low Speed (1.5 Mbps), Full Speed (12 Mbps) or High Speed (480 Mbps). Additionally, the USB84604’s integrated battery-charger-detection circuitry supports downstream battery detection and charging, providing the ability to replace external battery chargers with advanced battery-charging modes.


To ensure optimised signal strengths and robust operation in the harsh Electromagnetic Interference (EMI) environments typical of automotive applications, the chip has been equipped with Microchip’s VariSense and PHYBoost technologies.

The USB84604 functionality and configurations can be loaded from external Flash. Its on-chip, One-Time-Programmable (OTP) memory can be used to load permanent configurations and its System Management Bus (SMBus) slave interface can be used to customise the functionality of the USB84604. This interface enables control of the digital and USB lines for internal testing, configuration of the hub to function with the desired options when enumerating, and the loading of custom firmware.

The USB84604 UCH2 also enables applications to communicate via multiple protocols and methods, such as I2C, SPI, UART and GPIO. This