USB-PD Ctl
A USB-PD controller handles supported USB Power Delivery communication and port behavior. Source, sink, dual-role, programmable-supply and protocol-version capabilities depend on the exact device and configuration. A USB-C connector or PD label does not guarantee a particular voltage or wattage.
In the cited TPS25750 example, the controller detects attachment and orientation using CC pins, then exchanges USB-PD messages over the connected CC path using biphase-mark coding. Its configured policy handles the port's power role and controls power paths. Internal power switches or external switch control are model-specific; they are not a substitute for the system's required power-conversion circuitry.
In plain terms
Think of it as the negotiator, not the power station. It helps the two ends agree on a supported power arrangement, then coordinates the switches and power circuitry that actually deliver it.
Why designers use it
- Implement a supported USB-C power-input or power-output design.
- Coordinate power negotiation with a compatible charger or system controller.
- Manage attachment, orientation and configured power-path behavior.
Best for
- USB-PD power ports
- Compatible charging-system control
- Configured source or sink designs
Key specifications
- Protocol and role: Exact supported features and configuration (Check source, sink, dual-role and optional capabilities.)
- Power path: System-level voltage and current capability (A single switch rating does not establish the USB contract.)
- Connections: Exact package and reference design (CC, VBUS, control and charger interfaces are distinct functions.)
When not to use it
- When the required protocol features or power role are unsupported by the selected controller.
- When the connector, cable, protection, converter or power switches cannot support the intended contract.
Common mistakes
- Assuming every USB-PD controller supports the latest protocol revision or the same maximum power.
- Treating a CC pull-down resistor as permission to draw any desired current.
- Confusing a power-path switch with a voltage-converting regulator.
- Assuming power negotiation also provides DisplayPort routing or every other USB-C feature.
Where you will find it
- TI's TPS25750 Rev. A data sheet documents a USB-PD 3.0 controller with configuration and interfaces for an external battery charger. It is a documented architecture example, not a claim of current recommended-for-new-design status.
- The TPS25750D and TPS25750S diagrams show different high-voltage power-path arrangements. Their shared family name does not make their connections interchangeable.
A short history
This guide uses TI's documented TPS25750 architecture to separate communication, configuration, switching and power conversion. Capabilities from later USB-PD revisions are not retroactively assigned to this example, and no undocumented charger or laptop teardown is implied.
Good to know
- The same CC connection participates in attachment detection and carries USB-PD communication.
- An integrated power switch can connect a supported power path without being the circuit that creates its voltage.