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Suspend PIN status while charging from an external USB power adapter apart from PC

Bijeta chakraborty9485
Prodigy 500 points
Other Parts Discussed in Thread: TUSB2036

Hello Team,

My customer is making a small card called as BB Adapter with two USB ports and power supply circuitry including a battery charging Circuit.They are planning to use a USB Hub that will detect the different system states and control the current taken from PC and for that downstream port HUB TUSB2036 is being considered.There will be two USB ports : One for normal USB connection to connect any device like Memory Card Reader ,hard disk etc. another USB port will be either connected to PC or to an external power Adapter i.e.additional requirement to support battery charging from the external USB Power Adapter (instead of PC USB port).In that case what will be the state of SUSPEND pin. External USB Power Adapter will have D+ and D- lines shorted with 200Ohm resistor and only 5V power and Ground will be available.If the SUSPEND output is active then it will disable the charging circuit and we will not be able to charge from external USB adapter. 

Also,apart from the throughput differences what can be other design challenges faced when the system has the USB1.1  and we plug in USB2.0 HUB.

Please let me know if you have any questions further to be more clear on the query stated above.

Thanks and Regards

Bijeta Chakraborty

  • 0
    TI__Genius 16440 points

    Bijeta,

    I have some questions about your post...

    The TUSB2036 has one upstream port that must be connected to the HOST system (typically a PC) and either 2 or 3 downstream ports that get connected to either peripheral devices or another hub.   These are the only legal connections to a downstream port.

    You state:"another USB port will be either connected to PC or to an external power Adapter i.e.additional requirement to support battery charging from the external USB Power Adapter (instead of PC USB port)."  This is not a legal connection.  The downstream port can NOT connect to another PC.  I am also confused what you mean by it will be connected to an exteranl power adapter.  Is this incoming power or are you expecting the TUSB2036 to supply power to this adapter?

    Specific to your question, the hub will be suspended if it is not connected on the upstream port.

    USB 1.1 does not exist anymore, the USB 2.0 specification replaced the USB 1.1 specification.  The USB 2.0 specification defines three speed nodes for data transfer: USB low-speed is 1.5Mbps, USB full-speed is 12 Mbps, and USB high-speed is 480 Mbps.

    The TUSB2036 is a USB full-speed hub, as such it has a maximum data transfer rate of 12 Mbps. 

    Does your customer have a system block diagram of what they are trying to do?  I am not sure they understand how the hub is intended to be used?