Low power mode FX3S

[JaYe_3798301]

Hi,

I am a newbie to use the FX3 series USB controller.

I am now designing a product using the FX3s to communicate with PC and another special USB host device, which has a strict power limitation below 50 mA.

While attached to the special USB host, the speed is not important. 

So I am now looking for every possible way from hardware design to firmware implementation to reduce the power consumption.

Would force the FX3 enter USB 2.0 high speed mode help to reduce the power consumption?

Would the crystal frequency selection between 19.2, 26, 38.4, and 52 MHz also affect the power consumption?

Any other suggestions are more than welcomed.

Thanks,

Jay

[SrinathS_16 · Accepted solution]

Hello Jay,

- Please let us know what is the current that you are referring to. Is it only the current from the USB host or the entire FX3 chip (assuming the case of a self powered device)?

- The core power consumption of FX3 (including VDD, AVDD, U3TX_VDDQ, U3RX_VDDQ) accounts to a maximum of 200mA whereas the USB PHY current accounts only to a maximum of 60mA. So, to reduce the power drawn from the USB host, the FX3 can be used in a self-powered configuration with the core power derived from an external power supply.

EDIT:

Refer to EZ-USB® FX3™ Power Consumption – KBA85505  for details on power consumption by FX3/FX3S.

Best regards,

Srinath S