Hi,
VCONN power is a alternative power source for CCG3, please refer the USB Type-C spec
Once the connection between host and device is established, the CC pin (CC1 or CC2) in the receptacle that is not connected via the CC wire through the standard cable is repurposed to source VCONN to power circuits in the plug needed to implement Electronically Marked Cables (see Section 4.9), VCONN-Powered Accessories and VCONN-Powered USB Devices. Initially, the source supplies VCONN and the source of VCONN may be swapped using USB PD VCONN_Swap.
Electronically marked cables may use VBUS instead of VCONN as VBUS is available across the cable. VCONN functionally differs from VBUS in that it is isolated from the other end of the cable. VCONN is independent of VBUS and, unlike VBUS which can use USB PD to support higher voltages, VCONN voltage stays within the range of 3.0 to 5.5 V (vVCONNValid).
1. Can we leave CCG3's Vsys pin unconnected ( floating)?
It is suggested not to leave it floating. If you want to leave it floating, please connect an alternate power source for Vconn. ( In your case VBUS).
2. What is consideration the reference design want to connect VCONN to Vsys pin? Becauase CCG3 is able to operate from supply source VBUS.
Please refer my above explanation. Also please refer the below image for more understanding,
The firmware expects the chip to be powered using VCONN. If you don't want to connect VCONN you will have to modify firmware to stop VCONN monitoring. As VCONN is monitored, I recommended you to use it.
In EZ-PD Config utility, VCONN required and VBUS required are defined to specify whether VCONN or VBUS is required for normal operation of device during alternate mode. Hence proper changes has to be made.
Regards,
Abhilash P
Hi,
VCONN power is a alternative power source for CCG3, please refer the USB Type-C spec
Once the connection between host and device is established, the CC pin (CC1 or CC2) in the receptacle that is not connected via the CC wire through the standard cable is repurposed to source VCONN to power circuits in the plug needed to implement Electronically Marked Cables (see Section 4.9), VCONN-Powered Accessories and VCONN-Powered USB Devices. Initially, the source supplies VCONN and the source of VCONN may be swapped using USB PD VCONN_Swap.
Electronically marked cables may use VBUS instead of VCONN as VBUS is available across the cable. VCONN functionally differs from VBUS in that it is isolated from the other end of the cable. VCONN is independent of VBUS and, unlike VBUS which can use USB PD to support higher voltages, VCONN voltage stays within the range of 3.0 to 5.5 V (vVCONNValid).
1. Can we leave CCG3's Vsys pin unconnected ( floating)?
It is suggested not to leave it floating. If you want to leave it floating, please connect an alternate power source for Vconn. ( In your case VBUS).
2. What is consideration the reference design want to connect VCONN to Vsys pin? Becauase CCG3 is able to operate from supply source VBUS.
Please refer my above explanation. Also please refer the below image for more understanding,
The firmware expects the chip to be powered using VCONN. If you don't want to connect VCONN you will have to modify firmware to stop VCONN monitoring. As VCONN is monitored, I recommended you to use it.
In EZ-PD Config utility, VCONN required and VBUS required are defined to specify whether VCONN or VBUS is required for normal operation of device during alternate mode. Hence proper changes has to be made.
Regards,
Abhilash P
Hi,
Please use EZ-PD Config utility and modify the section " VBUS required" and " VCONN required" based on your requirements.
Regards,
Abhilash P
