6

Application

The sections below are not part of the ST product specification. They are intended to give a generic application

overview to be used by the customer as a starting point for further implementations and customizations. ST does

not warrant compliance with customer specifications. Full system implementation and validation are under the

customer’s responsibility.

6.1

General information

6.1.1

Power supplies

The STUSB4500 can be supplied in three different ways depending on the targeted application:

•

•

Through the VSYS pin only for AC powered applications with a system power supply delivering 3.3 V or 5 V

•

Through the VDD and VSYS pins either for applications powered by a battery with dead battery mode

VDD and VSYS power supplies are present, the low power supply VSYS is selected when VSYS voltage is

above 3.1 V. Otherwise VDD is selected

6.1.2

Powering a system under high charging profile only

charging profile above 5 V has been negotiated (PDO2 or PDO3) with the source (see Section 3.3 Auto-run

mode).

This feature can be turned on thanks to NVM bit POWER_ONLY_ABOVE_5V (see Section 5 Start-up

configuration). When the bit value is set to logic level high, the VBUS_EN_SNK pin is asserted only when a PDO2

or PDO3 explicit contract is established with the source (see Section 2.2.10 VBUS_EN_SNK).

receptacle. The source and the sink stay electrically connected through the CC pins. Thus, when the source is

able later to provide power capabilities corresponding to those expected by the sink, a new negotiation is again

possible upon source request. If the PDO negotiation succeeds, the VBUS_EN_SNK pin is asserted which allows

the system to be powered at the negotiated PDO profile.

This feature is suited for sink devices requiring high power charging profile above 5 V to be fully operational.

6.1.3

Connection to MCU or application processor

The STUSB4500 runs as a standalone USB PD sink controller. The connection to an MCU or an application

processor is optional. However, an I²C interface with an interrupt allows simple connection to most of MCU and

SOC of the market.

When a connection through the I²C interface is implemented, it provides extensive functionality during the system

operation. For instance, it may be used to:

1.

Define the port configuration during system boot (in case the NVM parameters are not customized during

manufacturing)

2.

Provide a diagnostic of the Type-C connection in real time

the default values from the embedded NVM. At power-up, the loading phase starts when the voltage level on the

VREG_1V2 output pin of the 1.2 V internal regulator reaches 1.08 V to release the internal POR signal. After a

reset, the loading phase starts when the signal on the RESET pin is released.

STUSB4500

Application

DS12499 - Rev 2

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