FTDI Community
General Category => Discussion - Hardware => Topic started by: ppeter on October 27, 2017, 03:17:43 PM
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According to the datasheets VCCIO is the supply for the embedded voltage level translator and VCC the supply for the IC itself. However, I could not find information on the power sequencing:
* Is it allowed to power the IC via VCC and keep VCCIO turned off?
* Is it allowed to power-off VCCIO while VCC is still powered?
* Is it allowed to power-off VCC while VCCIO is still powered?
I'm designing low-power circuit (<50uA idle) and plan to use a FT230X or similar for occasional data readout and configuration. If it was possible to switch off VCCIO (and set all outputs from the uC tristate or GND) it would reduce power consumption and cost (no additional buffer needed). The uC could sense if VBUS is present and only then power-up VCCIO. VBUS would be tied to VCC and directly supply the FT-X IC when available.
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Hello,
Please refer to the FT230X Datasheet (http://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT230X.pdf) section 6 USB Power Configurations for some power configurations.
You should either choose a bus powered design, or self-powered design, and nothing in between.
VCC and VCCIO must always be applied at the same time.
You can also use the PWREN# signal (assigned to one of the CBUS pins) which indicates when the device has been enumerated by a USB Host.
The USB Host should also put the device into a low power suspend state, if the USB data bus is idle for >3ms.
Please also reference our Development Modules (http://www.ftdichip.com/Products/Modules/DevelopmentModules.htm) such as the FT-X Breakout Modules (http://www.ftdichip.com/Products/Modules/DevelopmentModules.htm#FT-X Breakout) and FT-X Development Modules (http://www.ftdichip.com/Products/Modules/DevelopmentModules.htm#FT-X) which can be used for test and development.
Best Regards,
FTDI Community