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Customer refer to datasheet - Figure 14. USB Type-C to HDMI Adapter Application schematic.
now has two question:
1). what purpose does it provide two power path to CCG3 ? (1). VCONN connect to Vsys pin (2) . VBUS internal LDO?
2). if connecting HDMI only and dis-connecting c port, why ... you can measure 2.8V on Vddio pin?
Solved! Go to Solution.
- Labels:
-
USB EZ-PD Type-C
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Hi Finix,
If you feel 2.9V on HPD pin is too high, you can decrease the pull down resistor in HPD.
There's no way to completely avoid this. You can check the internal structure of PSoC4 GPIO from AN86439. There's a clamp didoe.
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Hi,
1. VCONN power is a alternative power source for CCG3, please refer to 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).
2.It probably came from the reverve current from the power supply of HDMI port.
As you can see, the two chip are not electrical isolated.
Regards,
Eddie
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Hi, Eddie,
Sorry, we have another project is C to DP,
if connecting DP only and dis-connecting c port, why ... I can measure 2.9V on HPD pin and 2.68V on Vddio pin?
BR
Ivan
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Hi Ivan,
HPD pin is used for detect the presence of DP signal, so it is expected that HPD is high. And the voltage on VDDIO is probably the reverse current of HPD since VDDIO directly provide power for GPIO.
Regards,
Eddie
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Hi Eddie,
"HPD pin is used for detect the presence of DP signal, so it is expected that HPD is high. And the voltage on VDDIO is probably the reverse current of HPD since VDDIO directly provide power for GPIO. "
Is this could be prevent?
Regards,
Finix
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Hi Finix,
Why do you want to prevent this? HPD(Hotplug detect) high means DP is attached, that's the desired function.
Regards,
Eddie
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Hi Eddie,
I means that prevent "reverse current of HPD to VDDIO",
because if VDDD connect to VDDIO will make "reverse current" back inside CCG
Regards,
Finix
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Hi Finix,
If you feel 2.9V on HPD pin is too high, you can decrease the pull down resistor in HPD.
There's no way to completely avoid this. You can check the internal structure of PSoC4 GPIO from AN86439. There's a clamp didoe.