USB 2.0 Hi-Speed 3-Port Hub Controller Optimized for Portable Applications
Datasheet
Chapter 8 Functional Descriptions
This chapter provides additional functional descriptions of key device features.
8.1
Battery Charger Detection & Charging
The USB3813 supports both upstream battery charger detection and downstream battery charging.
The integrated battery charger detection circuitry supports the USB-IF Battery Charging (BC1.2)
detection method and most Apple devices. These circuits are used to detect the attachment and type
of a USB charger and provide an interrupt output to indicate charger information is available to be read
from the device’s status registers via the serial interface. The USB3813 provides the battery charging
handshake and supports the following USB-IF BC1.2 charging profiles:
DCP: Dedicated Charging Port (Power brick with no data)
CDP: Charging Downstream Port (1.5A with data)
SDP: Standard Downstream Port (0.5A with data)
Custom profiles loaded via SMBus or OTP
The following sub-sections detail the upstream battery charger detection and downstream battery
charging features.
8.1.1
Upstream Battery Charger Detection
Battery charger detection is available on the upstream facing port. The detection sequence is intended
to identify chargers which conform to the Chinese battery charger specification, chargers which
conform to the USB-IF Battery Charger Specification 1.2, and most Apple devices.
In order to detect the charger, the device applies and monitors voltages on the upstream DP and DM
balls. If a voltage within the specified range is detected, the CHRGDET[1:0] signals will be asserted
and the will be updated to reflect the proper status.
The device includes the circuitry required to implement battery charging detection using the Battery
Charging Specification. When enabled, the device will automatically perform charger detection upon
entering the Hub.ChgDet stage in Hub Mode. The device includes a state machine to provide the
detection of the USB chargers listed in the table below. The type of charger detected is returned in the
CHARGER_TYPE field of the .
Table 8.1 Chargers Compatible with Upstream Detection
USB ATTACH TYPE
DP/DM PROFILE
Shorted < 200ohm
VDP reflected to VDM
15Kohm pull-down on DP and DM
CHARGERTYPE
001
010
(EnhancedChrgDet = 1)
011
DCP (Dedicated Charging Port)
CDP (Charging Downstream Port)
SDP
(Standard Downstream Port)
USB Host or downstream hub port
Apple Low Current Charger
Apple High Current Charger
Apple
Apple
100
101
SMSC USB3813
49
Revision 1.0 (06-17-13)
DATASHEET
SMSC [ SMSC CORPORATION ]
