TUSB7340: Why should we need to use external power

Shu-Cheng LIN

Part Number: TUSB7340
Other Parts Discussed in Thread: TUSB8041A

Hi Sirs,

Sorry, one more question.

According to usb spec, there are two power type, self-power and bus-power. If we use bus-power, Powered stage is 2^nd stage. Why should we need to use external power ?

over 6 years ago

0 Malik Barton57 over 6 years ago

TI__Guru 64326 points

Shu-Cheng,

TUSB7340 is not a USB Hub. TUSB7340 is a USB 3.0-compliant xHCI host controller. Being a host controller, the system TUSB7340 is placed on sources Vbus to the down stream devices, including USB hubs that are bus powered or self powered (i.e. TUSB8041A, etc.), therefore a external power supply is needed.

0 Shu-Cheng LIN over 6 years ago in reply to Malik Barton57

Guru 11785 points

Hi Sirs,

Thanks for your reply.

May i know how to config PWRON_POLARITY from 0 to 1?

0 Malik Barton57 over 6 years ago in reply to Shu-Cheng LIN

TI__Guru 64326 points

Hi,

This register setting can be changed through firmware loaded through EEPROM option.

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TUSB7340: Why should we need to use external power