7 Replies Latest reply on Aug 9, 2019 12:45 AM by RajathB_01

    Force VCONN continuously on

    OlEr_1999891

      Hi!

       

      We have a dock using CCG4 and looking a creating a special dongle using CCG3 that can be connected to the dock. When the dongle is connected, it should source 20V power which then will be forwarded externally, but we want the CCG3-chip and some additional electronics be powered with the 5V provided by VCONN if possible. This so we don't need a secondary LDO/step-down converter in the dongle that will generate heat. Also we notice that when we power CCG3 over VBUS with 20V it becomes very hot, guessing from using the internal LDO for 20V > 3.3V/1.8V conversion.

       

      Noticed that there were a HDMI dongle ref-design were the CCG3 is supplied by VCONN power only, but what is the right PD configuration that a device need to trigger the CCG4 dock / host to provide continous VCONN power? I assume there are some settings in PD Configuration Utility that needs to be correct?  And using this setting, is it possible for a device to both source VBUS power and VCONN power?

       

      Is it possible via the CCG4 FW to manually override the control of VCONN power supply or that is all made in the binary part of the FW?

       

      Cheers

      Olof

        • 1. Re: Force VCONN continuously on
          RajathB_01

          Hi Olof,

           

          CCG4 will source VCONN on one of the CC lines that is terminated by Ra.

          CCG3 has integrated Ra termination on its VCONN pin # 6 on the 3120 part. This will call for 5V VCONN on this line.

          The other CC line will be open for CCG3 integrated Rd termination and this will call for VBUS.

           

          You can refer to any of our dongle reference design schematics (C-T-D / C-DP / C-HDMI).

           

          Regards,

          Rajath

          • 2. Re: Force VCONN continuously on
            OlEr_1999891

            Hi Rajath!

             

            Ok, so no additional FW or configuration changes needed in CCG4 or CCG3? Just a matter of connecting one CC-line on CCG3 to pin 6 and CCG4 will automatically and continously source 5V over that connected CC-line?

             

            Cheers

            Olof

            • 3. Re: Force VCONN continuously on
              RajathB_01

              Yes. You will have to route the VCONN to VSYS and VBUS to VBUS pin on CCG3. You can also use power 'OR'ing diodes to power VBUS pin from both VCONN and VBUS (refer Charge Through Dongle schematics).

               

              Regards,

              Rajath

              • 4. Re: Force VCONN continuously on
                OlEr_1999891

                Ok, just to clarify the details then:

                 

                 

                1. We power VSYS from VCONN. So Pin 6 + Pin 20 would both be powered by one of the CC-pins on the USB-C plug.

                2. We wire VDDD to VDDIO for internal GPIO power supply

                3. We also connect VBUS to Pin 31. But will this not mean that CCG3 will instead source power via VBUS + the internal LDO? Or since VCONN is 5V it will only source from the VSYS-pin instead? So, if there is no VCONN power, the CCG3 will automatically be powered via VBUS then? If yes, why the need for the exernal OR'ing diodes?

                4. No need to connected VBUS_P right since we are only Sink?

                 

                Cheers

                Olof

                • 5. Re: Force VCONN continuously on
                  RajathB_01

                  Regarding my last response, if you don't want to use VBUS to power the chipset, you can only route VCONN to VSYS and leave VBUS.

                  • 6. Re: Force VCONN continuously on
                    OlEr_1999891

                    Ok, got it.

                     

                    Thanks!

                    • 7. Re: Force VCONN continuously on
                      RajathB_01

                      1. We power VSYS from VCONN. So Pin 6 + Pin 20 would both be powered by one of the CC-pins on the USB-C plug.

                      >> Yes. Note that Pin 6 VCONN only provides termination, the VCONN supply will be used by pin 20, VSYS.

                       

                      2. We wire VDDD to VDDIO for internal GPIO power supply.

                      >> Right.

                       

                      3. We also connect VBUS to Pin 31. But will this not mean that CCG3 will instead source power via VBUS + the internal LDO? Or since VCONN is 5V it will only source from the VSYS-pin instead? So, if there is no VCONN power, the CCG3 will automatically be powered via VBUS then? If yes, why the need for the exernal OR'ing diodes?

                      >> That is one way of powering the chip - if you OR VBUS and VCONN to power pin 31, you need not use the VSYS pin. This way you can be sure CCG3 will not be damaged by high voltages on VCONN pin (VSYS requires regulated 5V, no protector behind the pin). But then you will always be drawing power from LDO.

                       

                      4. No need to connected VBUS_P right since we are only Sink?

                      >> Correct.

                       

                      Regards,

                      Rajath