XHRA-2HPA USB power detection
Posted: Sat Jul 08, 2017 11:38 am
I have a few questions regarding the power detection of the XHRA-2HPA.
Since I want to isolate my I2S board from USB, I use digital isolators and an independent power supply.
Pin 23, the USB_VBUS USB power detection is isolated and driven over an optocoupler circuit.
I don`t need any 5 volts, except for pin 23, the USB_VBUS Power Detect Pin.
Instead of using an extra 5V regulator (min. a zener diode), my question now is:
1. Is it possible to feed this pin with only 3.3V, resp. does the detection work with this voltage?
According to the data sheet, this is an I/O pin, and the supply voltage for the remaining pins should be around this level.
For this specifically pin, I cann`t find this, or any further information (e.g. min./max. voltage). Also the functional context with pin 15, the SELF_PWR pin as "USB power option" is missing.
2. I think I have to pull up this pin up for "self power", with my independent supply, is this correct?
For my understanding, the USB Power Detection Pin 23 serves shutting down some internal circuits, when there`s no USB connection available.
3. In this case, can I shut down the 24Mhz clock for some kind of standby mode (have also SPDIF inputs onboard) and is a reset necessary for waking the chip up again?
Thanks for any help!
Since I want to isolate my I2S board from USB, I use digital isolators and an independent power supply.
Pin 23, the USB_VBUS USB power detection is isolated and driven over an optocoupler circuit.
I don`t need any 5 volts, except for pin 23, the USB_VBUS Power Detect Pin.
Instead of using an extra 5V regulator (min. a zener diode), my question now is:
1. Is it possible to feed this pin with only 3.3V, resp. does the detection work with this voltage?
According to the data sheet, this is an I/O pin, and the supply voltage for the remaining pins should be around this level.
For this specifically pin, I cann`t find this, or any further information (e.g. min./max. voltage). Also the functional context with pin 15, the SELF_PWR pin as "USB power option" is missing.
2. I think I have to pull up this pin up for "self power", with my independent supply, is this correct?
For my understanding, the USB Power Detection Pin 23 serves shutting down some internal circuits, when there`s no USB connection available.
3. In this case, can I shut down the 24Mhz clock for some kind of standby mode (have also SPDIF inputs onboard) and is a reset necessary for waking the chip up again?
Thanks for any help!