 2015-2016 Microchip Technology Inc.

DS00001855D-page 25

USB5744

8.0

FUNCTIONAL DESCRIPTIONS

This section details various USB5744 functions, including:

• Downstream Battery Charging

• Resets

• Link Power Management (LPM)

• Port Control Interface

8.1

Downstream Battery Charging

The device can be configured by an OEM to have any of the downstream ports support battery charging. The hub’s role

in battery charging is to provide acknowledgment to a device’s query as to whether the hub system supports USB battery

charging. The hub silicon does not provide any current or power FETs or any additional circuitry to actually charge the

device. Those components must be provided externally by the OEM.

If the OEM provides an external supply capable of supplying current per the battery charging specification, the hub can

be configured to indicate the presence of such a supply from the device. This indication, via the PRT_CTL[4:1] pins, is

on a per port basis. For example, the OEM can configure two ports to support battery charging through high current

power FETs and leave the other two ports as standard USB ports.

For additional information, refer to the Microchip USB5744 Battery Charging application note on the Microchip.com

USB5744 product page at www.microchip.com/USB5744.

FIGURE 8-1:

BATTERY CHARGING EXTERNAL POWER SUPPLY

SOC

VBUS[n]

PRT_CTL[n]

INT

SCL

SDA

Microchip

Hub

DC Power