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USB Type-C/PD Frequently asked questions
Aug 17, 2018

what is meaning that how many meters pass how many Gbs of the high frequency cable?

Performance indicators of wire transmission

Low frequency: below 12KHz, the main parameters are capacitance, and the characteristic capacitance is unbalanced

High frequency: over 12KHz, parameters include attenuation, crosstalk, delay, delay difference, characteristic impedance, transmission speed, etc.

Common high-frequency related units and conversion dB dB, mainly described the voice class unit, attenuation and crosstalk Hz Hz, the unit of frequency Ω ohm, the unit of impedance Ps, ns, picosecond and nanosecond, time of unit conversion unit (thousand hexadecimal) T too (1012) G auspicious trillion (106) (109) M K painted qian (103) international unit M fine long hair (10-3) mu micro (10-6) n, (10-9) p skin (10-12) f fly (10-15)

High frequency line over several meters over how many G, mainly refers to, according to the test specification requirements, and the actual test data of the test wire, meet the parameters in the test specifications, that is, pass, do not meet the test specification requirements, that is, do not pass!(data description of the following bit examples)




How long can the existing pair of twisted wire materials or coaxial lines meet the requirements of USB 3.1 Gen1(5G)?

The following figure shows USB3.1 reference to the structure of stranded wire and coaxial wire.

The following figure respectively refers to the length of the type-c series


What's the difference between USB power transfer (USB PD) and USB type-c?

USB power transmission (USB PD) is a protocol specification that supports up to 100W power transmission and data communication in a single cable.

USB type-c is a new directionless forward and reverse USB connector specification that supports a variety of new standards, including USB 3.1 (Gen1 and Gen 2), Display Port, HDMI, and USB PD.

By default, the USB type-c port can support up to 5V3A for power transmission. If USB PD is implemented in the USB type-c port, it can support up to 100W power transmission.

Therefore, having a USB type-c port does not mean that it supports USB PD.

Is the USB btype-c connector mandatory for the USB 3.1 Gen 1 or Gen 2 specification?Is usbtype-c the same as usb3.0/3.1?

 At the moment, we can use the traditional Type - A or Type B connector to support the Gen 1 and Gen 2 specifications, USB Type - C specification is by the USB developer BBS (USB - IF) released A new interface certification specification, can support up to 100 w, power transmission and without the direction of the positive and negative in all USB 3.1 Gen 1 or Gen 2 specification product can use USB Type - C interface.

So our answer is: the USB type-c specification is independent of the USB 3.1 Gen1 or Gen 2 specification.

What are the contents of DFP, DRP and UFP respectively?

The DFP (downport of downport of downport) is the USB type-c Port installed on the host or hub and connected to the device, while the UFP (Upstream Port) is the device or hub with the host or hub.

USB type-c port connected to the USB port.

The Dual Role Port, a dual-role power Role is defined as either the Source or Sink Role on a USB type-c Port.

The DRP is different from the double role Power interface, double role Power interface means can be used as a Power Source (provider) and Sink (consumer) Power supply port, for example, laptop USB Type - C port support DRP (i.e., the Type - C dual role Power interface), both can be used as a Power Source (for connection to the removable disk or mobile phones), can also be used as a Sink (connection screen or Power adapter).

What is the configured channel (CC) line?What is the maximum speed of the CC bus?

The USB cable is a data cable used for usb-pd communication between port and EMCA.

There are two pins CC1 and CC2 on the USB type-c socket, one of which is identified as CC line based on the direction of the plug connected by USB type-c.

The CC cable is fixed for USB type-c plug.

The following functions can be run in a CC line:

Detect the direction of the USB type-c plug to establish USB data bus routing

Detect USB port connections from DFP to UFP

Establish the role of DFP and UFP between ports

Find and configure the VBUS

Configuration VCONN

Find and configure alternative backup and attachment modes

The bit rate of the reticcc line ranges from 270 Kbps to 300Kbps and the rating is 300Kbps.

What's the difference between c.c.cypress usb-pd2.0 and qualcomm QC quick charge?

The USB USB PD 2.0 is a protocol developed by usb-if, which can provide up to 100 W (20V, 5A) power supply mechanism between USB devices. It can also support both USB and non-usb data signals on the USB type-c port, which enables flexible negotiation of power supply direction between host and peripheral devices.

S qualcomm ® Quick Charge ™ is charging qualcomm proprietary protocol, using a support qualcomm Quick Charge agreement custom charger for equipment also support the deal.Quick Charge 2.0 can transmit up to 60 W of power supply, but unlike usb-pd, Quick Charge 2.0 cannot support both power transmission and data transmission and does not support flexible selection of power supply direction during charging.

How many power transfer objects (PDO) can a USB PD controller support?What power profiles are supported?

The power cypress usb-pd supports up to 7 PDO applications for pull current and irrigation current.

The USB PD specification does not require which power configuration files the application device needs to support.Pull current and feed current PDO depend on application design.Part a.1 of the USB type-c specification defines the standardized combination of voltage and different current ranges. It should be noted that the power configuration file defined in part a. 1 is only recommended to use the power configuration file, not mandatory, but at least one pull-current PDO can be used to support 5V.

Can the USB and standard 5 V VBUS capabilities be used for USB only with usbtype-c ports?

Free yes, you can use USB type-c ports that have only USB functionality and support the standard 5-v VBUS.

Host terminal: the default port current provided by host type-c port is 5V 3A and 5V 1.5a, respectively, for USB 2.0 (500mA) and USB 3.0 (900mA).The USB type-c host displays the current capacity by attaching an appropriate pull-up resistor Rp to the CC line (CC1 and CC2).

Device side: only usbtype-c devices are supported, and a 5.1k pull-down resistor Rd needs to be inserted in the CC line.If the device is equipped with a USB type-c socket, Rd should be serialized on both the CC1 and CC2 lines.However, if the device is equipped with a type-c plug, simply connect Rd on the CC line.

What does the ubtype-c equipment do with VBUS voltage greater than 5V?

When the device needs a charging voltage greater than 5V, then the host is required to have the ability of usb-pd communication. The usb-pd pull current transfers the power supply configuration file to the device, which then requests one of the installed power supply configuration files according to its charging current capacity. After establishing the protocol, the host can provide the requested voltage on the VBUS.