USB Type-C/PD Frequently Asked Questions Answered

☞ What is the difference between USB Power Delivery (USB PD) and USB Type-C?

■ USB Power Delivery (USB PD) is a protocol specification that supports up to 100W of power delivery and data communication simultaneously in a single cable.

■ USB Type-C is a new non-directional forward and reverse USB connector specification that supports a wide range of new standards, including USB 3.1 (Gen1 and Gen 2), Display Port, HDMI, and a host of new standards such as USB PD.

■ USB Type-C ports can support up to 5V3A by default, and up to 100W if USB PD is implemented in the USB Type-C port.

Therefore, having a USB Type-C port does not mean it supports USB PD.

☞ Is the USBType-C connector mandatory for USB 3.1 Gen 1 or Gen 2 specifications?Is USBType-C equivalent to USB 3.0/3.1?

■ Currently, we can use traditional Type-A or Type-B connectors to support Gen 1 and Gen 2 specifications. The USB Type-C specification is a new interface certification specification released by the USB Developers Forum (USB-IF), which supports up to 100W of power transfer and non-directional forward and reverse plugging, and all USB 3.1 Gen 1 or Gen 2 specification products can use the USB Type-C interface. All USB 3.1 Gen 1 or Gen 2 compliant products can utilize the USB Type-C interface.

The answer is that the USB Type-C specification is independent of the USB 3.1 Gen1 or Gen 2 specification.

☞ What are DFP, DRP and UFP?

■ DFP (DownstreamFacing Port) is a USB Type-C type port installed on a host or hub connected to a device ■ UFP (Upstream Facing Port) is a USB Type-C type port installed on a device or hub connected to a host or hub.

The UFP (Upstream Facing Port) is a USB Type-C type port on a device or hub that is connected to a host or hub ■ DFP.

DRP (Dual Role Port) is a definition of a USB Type-C port that can act as a Source or Sink.

The DRP described above is different from the Dual Role Power Interface, which refers to a power port that can act as a Power Source (Provider) and a Sink (Consumer). For example, a USB Type-C port on a laptop computer that supports DRP (i.e., a Type-C Dual Role Power Interface) can be used as either a Power Source (when connecting a removable disk or cell phone) or as a Sink. For example, a USB Type-C port on a laptop supports DRP (i.e., Type-C Dual Role Power Interface), which can be used as either a Power Source (when connecting a removable disk or cell phone) or a Sink (when connecting a display or power adapter).

☞ What is the Configuration Channel (CC) line and what is the maximum speed of the CC bus?

■ The CC bus is a data line used for USB-PD communication between the port and the EMCA.

■The USB Type-C plug has two pins, CC1 and CC2, one of which is recognized as the CC line based on the plug orientation of the USB Type-C connection.

■The CC line is fixed for USB Type-C plugs.

■ The CC wire operates the following functions:

■ Detecting the USB Type-C plug orientation to establish USB data bus routing

Detects USB port connections from DFP to UFP

Establishes the roles of the DFP and UFP between ports

Find and configure VBUS

Configure VCONN

Find and configure optional standby and accessory modes

The bit rate of the ■CC line varies from 270 Kbps to 300 Kbps and is rated at 300 Kbps.

☞What is the difference between Cypress USB-PD2.0 and Qualcomm QC fast charging?

■USB-PD 2.0 is a protocol developed by USB-IF that provides a power supply mechanism for up to 100 W (20V, 5A) between USB devices, and also supports both USB and non-USB data signals in the USB Type-C port, which provides flexibility in negotiating the direction of the power supply between the host computer and the peripheral.

Qualcomm® Quick Charge™ is Qualcomm's proprietary charging protocol that uses a custom charger that supports the Qualcomm Quick Charge protocol to charge a device that also supports the protocol.Quick Charge 2.0 can transfer up to 60 W of power, but unlike USB-PD, Quick Charge 2.0 does not support both power and data transfer, nor does it support both. Unlike USB-PD, Quick Charge 2.0 does not support both power and data transfer, nor does it support the flexibility to select the direction of power during charging.

☞ What is the maximum number of Power Delivery Objects (PDOs) that can be supported by Cypress USB-PD controllers? What are the supported power profiles?

■ Cypress USB-PD supports up to 7 PDOs for current draw and current sink applications.

■ The USB-PD specification does not require which power profiles an application device needs to support. The current draw and current sink PDOs depend on the application design.Section A.1 of the USB Type-C specification defines standardized combinations of voltages and different current ranges.It is important to note that the power profiles defined in section A.1 are only recommended power profiles and are not mandatory, but at least one of them needs to be able to be used to support 5V current draw PDOs.■ The USB-PD specification supports up to 7 PDOs for current draw and current sink applications.■ USB-PD specification does not require the application device to support any power profiles.

☞ Can I use only USB and standard 5 VBUS functions for USBType-C ports?

■ Yes, you can use a USB Type-C port with only USB functionality and standard 5-V VBUS support.

Host Side: The default port currents provided by the host Type-C port for USB 2.0 (500mA) and USB 3.0 (900mA) are 5V 3A and 5V 1.5A, respectively. USB Type-C hosts indicate the current capacity by stringing an appropriate pull-up resistor, Rp, across the CC lines (CC1 and CC2).

Device Side: Supports USBType-C devices only, and requires a 5.1K pull-down resistor Rd on the CC line; if the device is equipped with a USB Type-C socket, Rd needs to be connected on both the CC1 and CC2 lines; however, if the device is equipped with a Type-C plug, Rd only needs to be connected on the CC line.

☞How does USBType-C device handle VBUS voltage greater than 5V?

■ When a device requires a voltage greater than 5V, it requires the ability to communicate with USB-PD, which pulls current to send a power profile to the device, and then the device requests one of the installed power profiles based on the current capacity of the device, and then the host computer can provide the requested voltage on VBUS after the protocol has been established.