“VBUS_SENSE pin monitoring” relies, by default, on a valid VBUS voltage range. The voltage range condition can

be disabled to consider UVLO threshold detection instead. The monitoring condition of the VBUS voltage can be

changed through NVM programming (see Section 6 Start-up configuration) and also by software through the I²C

interface. VBUS_EN_SRC pin is maintained asserted as long as the device is attached and a valid voltage

condition on the VBUS is met.

3.4

VCONN supply

3.4.1

VCONN input voltage

VCONN is a regulated supply used to power circuits in the plug of USB3.1 full-featured cables and other

accessories. VCONN nominal operating voltage is 5.0 V +/- 5%.

3.4.2

VCONN application conditions

VCONN pin of the STUSB1702 is connected to each CC pin (CC1 and CC2) across independent power switches.

The STUSB1702 applies VCONN only to the CC pin not connected to the CC wire when all below conditions are

met:

•

The device is configured in source power role

•

VCONN power switches are enabled

•

A valid connection to a sink is achieved

•

Ra presence is detected on the unwired CC pin

•

A valid power source is applied to the VCONN pin with respect to a predefined UVLO threshold

3.4.3

VCONN monitoring

The VCONN monitoring block detects if VCONN power supply is available on the VCONN pin. It is used to check that

VCONN voltage is above a pre-defined undervoltage lockout (UVLO) threshold to allow the enabling of the VCONN

power switches.

The default value of the UVLO threshold is 4.65 V typical for powered cables operating at 5 V. This value can be

changed by software to 2.65 V typical to support VCONN-powered accessories that operate down to 2.7 V.

3.4.4

VCONN discharge

The behavior of Type-C FSMs is extended to an internal VCONN discharge path capability on the CC pins in

source power mode only. The discharge path is activated during 250 ms from sink detachment detection. This

feature is disabled by default. It can be activated through NVM programming (see Section 6 Start-up

configuration) and also by software through the I²C interface.

3.4.5

VCONN control and status

The supplying conditions of VCONN across the STUSB1702 are managed through the I²C interface. Different I²C

registers and bits are used specifically for this purpose.

3.4.6

VCONN power switches

Features

The STUSB1702 integrates two current limited high-side power switches with protection that tolerates high

voltage up to 22 V on the CC pins.

Each VCONN power switch is presents the following features:

•

Soft-start to limit inrush current

•

Constant current mode overcurrent protection

•

Adjustable current limit

•

Thermal protection

STUSB1702

VCONN supply

DS12664 - Rev 1

page 10/38