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USB Hosts Hubs Transceivers

user_4143136
New Contributor

Hi,

We will use CY7C65632-28Pin in our design and we are planning to drive USB load switch via PWR# pin. In community there is a similar discussion(Re: cy7c65642-28 pin 12cSDA pin) which is related with my question but differently I would like to ask in which cases PWR# will be driven low? It is not clear.  For example once a device is connected to one of downstream ports what will be the state of  PWR# pin(is it driven low, or high-Z)  after enumeration is done(Datasheet says that host may power each port by sending a SetPortPower request)? And the second case if the hub gets a trig from one of OVR# pin, then does it change PWR# pin state?

Regards,

Zafer Çalışkan

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1 Solution
Sananya_14
Moderator
Moderator

Hi Zafer,

If the PWR# pin is set for polarity as active low, it will be low when the downstream port is powered after enumeration.This state is after host has sent a SetPortPower Request for the particular port. When hub detects overcurrent on any of the OVR# pins, the host is notified and it disables power for the particular port. The PWR# pin will then be in deasserted state or high till power is enabled again.

Best Regards,

Sananya

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Sananya_14
Moderator
Moderator

Hi Zafer,

If the PWR# pin is set for polarity as active low, it will be low when the downstream port is powered after enumeration.This state is after host has sent a SetPortPower Request for the particular port. When hub detects overcurrent on any of the OVR# pins, the host is notified and it disables power for the particular port. The PWR# pin will then be in deasserted state or high till power is enabled again.

Best Regards,

Sananya

View solution in original post

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