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I am trying to make my own USB hub using USB7216 IC, and trying to understand how should I power the 'VCORE' pin.

Based on the datasheet, it should receive a ~1.15V power:

Page 42:

VCORE power

Page 44:

VCORE POWER

But it looks odd to me that:

  1. the schematic they posted at page 7 and page 26 does not show the voltage of VCORE:

Block diagram VCORE

POWER CONNECTION VCORE

  1. Usually, the ICs that I use like 232rl and USB isolators, create the voltage to power their internal logic from the main power (3.3V or 5V) on their own, and do not need a second, separate power.

  2. Powering ICs at 1.15V is something I hear for the first time. Usually I see power specifications as low as 3.3V.

But since the datasheet says I need to use an external Power of 1.15V, I will. I just want to hear your thoughts I want to know if there is any hint I missed, or someone with more experience on usb hubs can tell me that powering such ICs with voltage lower to 3.3V is common. After all, there are not many tutorials on USB hubs.

When I use the IC, I will also check powering it only at 3.3V, and see its VCORE pin, if it generates this 1.15V on its own.

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The Vcore needs an external power supply just as the 3V3 needs one: -

enter image description here

the schematic they posted at page 7 and page 26 does not show the voltage of VCORE

Showing the 3.3 voltage is pretty much a defined thing but, maybe they have different products that use a different core voltage and, that diagram is therefore "generic" and suits several different variants. Maybe, when the drawing was made they hadn't decided upon the actual core voltage supply.

I've come across several power supply designs that generate tens of amps at circa 1 volt so, although I can't name other devices that use a low voltage core voltage (other than a whole load of FPGA devices and plenty of CPUs), they are fairly common-place.

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