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USB EZ-PD™ Type-C

KiLe_4629881
Level 3
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Level 3

If the CCG3120 is unpowered from either VSYS or VBUS and HPD is high, is there any concern or risk of damaging the device?

Based on our measurements I think in this state VDDIO will be back powered through internal body diodes. Is this a safe condition to be in? 

This is an easy condition to enter if the ccg3 is unplugged from the host, but still attached to a monitor. 

Since we were externally powering VDDIO - we noticed that this would cause the CCG3120 to get in a bad state. 

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ShifangZ_26
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Hi Kyle,

For the design of HPD signal, you should make sure the pull-down resistance on HPD signal is loaded and the value is large as possible, for example, 1M. The Body Diode max current from VDD to VSS is 100uA. You should meet this specification.

 

Best Regards,

Lisa

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ShifangZ_26
Moderator
Moderator 1000 replies posted 750 replies posted 500 solutions authored
Moderator

Hi Kyle,

For the design of HPD signal, you should make sure the pull-down resistance on HPD signal is loaded and the value is large as possible, for example, 1M. The Body Diode max current from VDD to VSS is 100uA. You should meet this specification.

 

Best Regards,

Lisa

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KiLe_4629881
Level 3
25 sign-ins 10 replies posted 10 questions asked
Level 3

Hi @ShifangZ_26 

Thank you for your reply, however could you clarify further? You did not really answer my question if this is safe in the reference design to backpower VDDD by the HPD gpio input.

Specifically. If the reference dongle design is unplugged from the usb-c side, and still plugged into a monitor, the monitor will drive HPD high to 3.3V, which will then be conducted through the body diode to VDDIO - and then to VDDD - which I assume would power up the CCG3 drawing more than the 100uA limit you mention. 

 

KiLe_4629881_0-1618338688599.png

 

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ShifangZ_26
Moderator
Moderator 1000 replies posted 750 replies posted 500 solutions authored
Moderator

Hi Kyle, 

 

You are correct.  Since GPIO structure have internal diode to VSS for ESD and voltage clamps. If the Voltage on VDDD is higher than 1.74V, and then CCG3 is starting to work, the Current shall be higher than 10mA. 

 

Best Regards,

Lisa

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