2.2.8

POWER_OK2/POWER_OK3

These pins report by default the status of the USB power delivery contract negotiation with the source.

Different configurations are proposed as stated in the table below to meet specific application requirements. The

configuration of the POWER_OK pins can be changed by NVM programming (see Section 5 Start-up

configuration).

Depending on the programmed configuration, they can be used in combination with VBUS_EN_SNK pin to enable

different power path scenarios.

POWER_OK2 pin is a high voltage open drain output that allows a PMOS transistor to be directly driven to enable

a power path.

POWER_OK3 is a low voltage open drain output.

Configuration ID

/NVM parameter

PWR_OK_CFG[1:0]

Pin name

Value

Description

Configuration 1: all PDOs on single VBUS power path

00b

VBUS_EN_SNK(1)

Hi-Z

No source attached

0

Source attached

POWER_OK2

Hi-Z

No functionality

POWER_OK3

Hi-Z

No functionality

Configuration 2: all PDOs on single VBUS power path + dedicated high power charging paths

10b

(default)

VBUS_EN_SNK

(1)

Hi-Z

No source attached

0

Source attached

POWER_OK2

Hi-Z

No PD explicit contract

0

PD explicit contract with PDO2

POWER_OK3

Hi-Z

No PD explicit contract

0

PD explicit contract with PDO3

Configuration 3: all PDOs on single VBUS power path + detection of USB Type-C current capability from source

11b

VBUS_EN_SNK(1)

Hi-Z

No source attached

0

Source attached

POWER_OK2

Hi-Z

No source attached or source supplies default

USB Type-C current at 5 V when source

attached

0

Source supplies 3.0 A USB Type-C current at 5

V when source attached

POWER_OK3

Hi-Z

No source attached or source supplies default

USB Type-C current at 5V when source attached

0

Source supplies 1.5 A USB Type-C current at 5

V when source attached

01b

Not applicable

1. The VBUS_EN_SNK pin values correspond to the default behavior

In case of configuration 2 (default):

•

When a PDO negotiation succeeds, the POWER_OK pin related to the negotiated PDO is enabled (active

low) when PS_READY message is received from the source

STUSB4500

Pin description

DS12499 - Rev 2

page 7/41