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June 2013 DocID024781 Rev 1 1/14
AN4308
Application note
Methods of STCC2540, STCC5011, STCC5021 control
By Ondrej Plachy
Introduction
The STCC2540 and STCC5011/STCC5021 (STCCxxxx in text below) devices are
combinations of a current limited USB port power switch with the USB 2.0 high-speed data
line (D+/D-) switch and the USB charging port identification circuit. Applications include
notebook PCs, all-in-one PCs, desktop PCs and other intelligent USB host devices.
The CTL1, CTL2 and CTL3 (CTLx in text below) logic inputs are used to select one of the
various operating modes provided by the STCCxxxx. These modes allow the host device to
actively select between:
“Standard Downstream Port” (SDP) (active USB 3.0 data communication with 900 mA
support or USB 2.0 data communication with 500 mA support)
“Charging Downstream Port” (CDP) (active USB data communication with 1.5 A support)
“Dedicated Charging Port” (DCP) (wall adapter emulation with no data communication
and up to 2.5 A support).
The STCCxxxx devices also integrate the autodetect feature that supports both DCP
schemes for the “Battery Charging Specification” (BC1.2, a maximum current draw of 1.5 A)
enhanced of Korean tablets support and the divider mode (a maximum current draw of 1 A
for the STCC5011 or 2 A for the STCC2540 and STCC5021) without the need for an outside
user interaction.
The STCC5011/STCC5021 (STCC50x1 in text below) devices support the peripheral
attachment detection in the G2/G3 power state and provide charging without the need of
waking up the whole host system. The attachment detection is controlled by a combination
of the EN and ATTACH_EN pins.
This Application note is focused on selecting the STCCxxxx operating mode by various
methods of driving its control inputs (CTLx, EN, ATTACH_EN).
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