Recently, there are nearly 20 large companies that have passed the USB4 certification. The unified USB4 industry will inevitably accelerate. Today, we will analyze and explain the application chips with the biggest difference between USB4 and ordinary USB. USB4 cables require ICs. One is to ensure the quality of high-speed signal transmission, and the other is to store relevant information about the cables, including whether they can support 3A to 5A with on-board current, etc. Because the signal transmission speed is faster now, the fastest single channel transmission reaches 20Gbps, and the wire cannot be too short. In order to ensure signal quality, chips with functions such as Re-timer and Re-driver are generally added. Re-timer is the function of recovering data, and Re-driver enhances the attenuation consumed signals. This type of IC can ensure that high-speed signals are accurately and stably transmitted within a specified distance.
also has another type called E-mark chip, which supports USB PD protocol communication. By communicating with this chip, in addition to knowing the ID information of the cable, you can also know whether the supported current can exceed 3A, so that you can distinguish between high-current cables and cables below 3A. It can not only meet the use of high currents, but also protect cables below 3A. The transmission speed is maximum 5Gbps. The load current will not exceed 3A, so the above IC is not needed. In the future, with the upgrade of the product, more and more chips will be applied to the product. Today, we have sorted out the specifications to provide basic explanations for the CC logic chip of Type-Ch and the E-MARK data cable with E-MARK
Association specifications. Type-C interface definition
TYPEC plug PLUG pin definition (Front View)
TYPEC female RECEPTOR pin definition (Front View)
Because the TYPEC protocol will support up to 20W or even greater power, it also has many Vbus pins and GND pins. In addition, because TYPEC also supports high-speed, DP and other protocols, there are also pins for other functions. Especially the CC pins in it. The USB Type-C interface contains 2 channel configurations (CC1 & CC2) signal pins (CC1 & CC2) for function negotiation. The above signals determine the interface insertion direction and are used to negotiate power supply functions, alternative modes and peripheral modes on the interface.
Association Specification CC Interpretation in
When you just started to contact TYPEC, you often see the function of CC this pin. At first I felt that CC was a simple signal, and sometimes I understood that CC should be similar to a single bus function, including data communication, or serial port function... These understandings are all problems. After some understanding, the preliminary summary is as follows, I hope it will be helpful to everyone. If any expert has seen it, please give me some advice.
CC actually has CC1 and CC2. Both signals are connected on the socket. However, in the plug, only CC1 or CC1&Vconn is generally used to determine different functions through Rd/Ra on CC1&CC2, whether there is load access, need to provide up to current, whether power supply is required, and other information.
CC pin in DFP has pull-up resistor Rp, and in UFP has pull-down resistor Rd. When not connected, DFP's VBUS has no output. After connecting, the CC pin is connected. The CC pin of DFP will detect the pull-down resistor Rd of UFP, which means that it is connected. DFP will turn on the Vbus power switch and output the power to UFP. Which CC pin (CC1, CC2) detects the pull-down resistor, determines the direction of the interface insertion, and switches RX/TX by the way. For example, when
CC1&CC2 is connected to pull-down resistor Rd, it means Debug accessory mode; when
CC1&CC2 is connected to Ra, it means Audio Adapter Accessory When Mode
CC1 is connected to Rd and CC2 is NC (or vice versa), it means that there is a load connection; when
CC1 is connected to Ra, CC2 is NC (or vice versa), it means that the power supply cable is connected, and there is no load connection (it means that the power supply is supplied to Vconn, and there is no need to power supply to VBUS); when
CC1 is connected to Rd and CC2 is connected to Ra, it means that there is a power supply cable, and then the load connection (powers to VBUS, C at the same time C2 serves as Vconn to power the internal chip of the cable by 5V, and CC1 transmits a signal to UFP); or UFP (uplink port, i.e. slave device) access (indicates that VBUS needs to be powered) Consider
In addition, for DFP that requires current output capability, it needs to be achieved through a CC pull-up resistor Rp of different values; for UFP, it is necessary to detect the voltage value on the CC pin to obtain the current output capability of the other party DFP.
According to the standard pull-down resistance is Rd=5.1k, and the pull-up resistance Rp is an uncertain value. USB Type-C depends on the different Rp, so the voltage detected in the CC pin is different to control the DFP power supply mode. In TYPEC, there is actually only one cc wire in the cable without chips. The cable containing the chip is not two cc wires, but one cc and one Vconn, which is used to power the chip in the cable (5V). At this time, the cc terminal does not have a pull-down resistor Rd, but a pull-down resistor Ra: 800-1200Ω.
CC1 and CC2 are two key pins, and they have many functions:
detects connections, distinguishes between front and back, and distinguishes between DFP and UFP;
actually only has one cc wire in a cable without chips. The cable containing the chip is not two cc wires, but one cc and one Vconn, which is used to power the chip in the cable (5V). At this time, the CC terminal does not have a pull-down resistor Rd, but a pull-down resistor Ra. (that is, when there is a chip in the cable, one CC transmits a signal, and one CC becomes Vconn for power);
devices that support PD must use CC Logic chips. USB Type-C currently supports up to 20V/5A. At this time, it must support USB PD, that is, an additional PD chip is required. So don’t think that the USB Type-C interface can support 20V/5A.
How to evaluate whether the device needs a CC logic chip
All fully functional Type-C cables should be packaged with E-Marker: USB Type-C active cable encapsulated with E-Marker chips, DFP and UFP can use the PD protocol to read the cable's properties: power transmission capability, data transmission capability, ID and other information; but USB2.0 Type-C cables can not package E-Marker.
All DFP devices require CC logic detection and control chip: When DFP detects a certain voltage on the CC pin, it is determined that the UFP device has been inserted or unplugged to provide and manage VBUS. VBUS must be turned off when no UFP device is plugged in. In
USB3.0/USB3.1 applications, all devices except UFP devices require CC logic detection and control chips: in USB2.0 applications, direction detection issues need not be considered, but in USB3.0 or USB3.1 applications, direction detection issues must be considered (there is an exception in one case, such as USB disks, mobile hard disks, etc., which do not consider direction and do not use CC chips.).
PD-held devices must use CC Logic chip: For UFP, it is necessary to detect the voltage value on the CC pin to obtain the current output capability of the other party's DFP. USB PD seems to be just a protocol for power transmission and management, but in fact it can change the port role, communicate with active cables, and allow DFP to become a powered device and many other advanced features.
All fully-functional Type-C cables should be packaged with E-Marker, but USB2.0 Type-C cables can not be packaged with E-Marker
To sum up, only UFPs (U disks, headphones, mice, etc.) that do not require current detection capability due to low power consumption do not require CC logic detection port control chips, all other DFPs and DRPs (such as computers, mobile phones, tablets, mobile power supplies), UFPs that need to detect DFP current output capability, and devices that support PD all require CC logic detection and port control chips.
CC logic chip and E-Mark chip
"PD-held devices must use CC Logic chip ", "Electronically Marked Cable: USB Type-C active cable encapsulated with E-Marker chip", "full-functional Type-C cable encapsulated with E-Marke" and other information.
CC logic chip is also aimed at the device end;
E-MARK is aimed at cables, and the specification often mentions that "Electronically Marked Cable" is actually what we call e-mark chip. E-MARK chip technology automatically identifies the voltage and current required for electronic products.
If the TYPE-C interface provides a voltage of more than 5V or a current of more than 3A, then the TYPE-C interface chip must be required to implement the USB PD protocol.
chip selection principle:
If your device uses a 5V voltage and does not exceed 3A current. Moreover, the device itself only supplies power to the outside, or only accepts power supply to the other party, and the power supply role and the data transmission role are matched by default (that is, the power supply is HOST, and the power consumption is Slave or device). Then there is no need for TYPE-C chip. Is it necessary to use the E-MARK chip on the
C-C transmission line? This criterion is, will the current exceed 3A during use? If not exceeded, it may not be required.
If the Battery Charging protocol is required, this requires an E-MARK chip, which can not only realize charging but also transmit data.
More cable industry information , you can follow the WeChat official account: Cable industry friends sharing circle
According to the standard pull-down resistance is Rd=5.1k, and the pull-up resistance Rp is an uncertain value. USB Type-C depends on the different Rp, so the voltage detected in the CC pin is different to control the DFP power supply mode. In TYPEC, there is actually only one cc wire in the cable without chips. The cable containing the chip is not two cc wires, but one cc and one Vconn, which is used to power the chip in the cable (5V). At this time, the cc terminal does not have a pull-down resistor Rd, but a pull-down resistor Ra: 800-1200Ω.
CC1 and CC2 are two key pins, and they have many functions:
detects connections, distinguishes between front and back, and distinguishes between DFP and UFP;
actually only has one cc wire in a cable without chips. The cable containing the chip is not two cc wires, but one cc and one Vconn, which is used to power the chip in the cable (5V). At this time, the CC terminal does not have a pull-down resistor Rd, but a pull-down resistor Ra. (that is, when there is a chip in the cable, one CC transmits a signal, and one CC becomes Vconn for power);
devices that support PD must use CC Logic chips. USB Type-C currently supports up to 20V/5A. At this time, it must support USB PD, that is, an additional PD chip is required. So don’t think that the USB Type-C interface can support 20V/5A.
How to evaluate whether the device needs a CC logic chip
All fully functional Type-C cables should be packaged with E-Marker: USB Type-C active cable encapsulated with E-Marker chips, DFP and UFP can use the PD protocol to read the cable's properties: power transmission capability, data transmission capability, ID and other information; but USB2.0 Type-C cables can not package E-Marker.
All DFP devices require CC logic detection and control chip: When DFP detects a certain voltage on the CC pin, it is determined that the UFP device has been inserted or unplugged to provide and manage VBUS. VBUS must be turned off when no UFP device is plugged in. In
USB3.0/USB3.1 applications, all devices except UFP devices require CC logic detection and control chips: in USB2.0 applications, direction detection issues need not be considered, but in USB3.0 or USB3.1 applications, direction detection issues must be considered (there is an exception in one case, such as USB disks, mobile hard disks, etc., which do not consider direction and do not use CC chips.).
PD-held devices must use CC Logic chip: For UFP, it is necessary to detect the voltage value on the CC pin to obtain the current output capability of the other party's DFP. USB PD seems to be just a protocol for power transmission and management, but in fact it can change the port role, communicate with active cables, and allow DFP to become a powered device and many other advanced features.
All fully-functional Type-C cables should be packaged with E-Marker, but USB2.0 Type-C cables can not be packaged with E-Marker
To sum up, only UFPs (U disks, headphones, mice, etc.) that do not require current detection capability due to low power consumption do not require CC logic detection port control chips, all other DFPs and DRPs (such as computers, mobile phones, tablets, mobile power supplies), UFPs that need to detect DFP current output capability, and devices that support PD all require CC logic detection and port control chips.
CC logic chip and E-Mark chip
"PD-held devices must use CC Logic chip ", "Electronically Marked Cable: USB Type-C active cable encapsulated with E-Marker chip", "full-functional Type-C cable encapsulated with E-Marke" and other information.
CC logic chip is also aimed at the device end;
E-MARK is aimed at cables, and the specification often mentions that "Electronically Marked Cable" is actually what we call e-mark chip. E-MARK chip technology automatically identifies the voltage and current required for electronic products.
If the TYPE-C interface provides a voltage of more than 5V or a current of more than 3A, then the TYPE-C interface chip must be required to implement the USB PD protocol.
chip selection principle:
If your device uses a 5V voltage and does not exceed 3A current. Moreover, the device itself only supplies power to the outside, or only accepts power supply to the other party, and the power supply role and the data transmission role are matched by default (that is, the power supply is HOST, and the power consumption is Slave or device). Then there is no need for TYPE-C chip. Is it necessary to use the E-MARK chip on the
C-C transmission line? This criterion is, will the current exceed 3A during use? If not exceeded, it may not be required.
If the Battery Charging protocol is required, this requires an E-MARK chip, which can not only realize charging but also transmit data.
More cable industry information , you can follow the WeChat official account: Cable industry friends sharing circle
