8

Copyright © 2012 Future Technology Devices International Limited

UMFT231XE

Version 1.0

Document Reference No.: FT_000652

Clearance No.: FTDI#

294

5.2

Bus Powered Configuration

GND

Jumper JP1 - Closed

GND

Jumper JP2- Closed

Alternative

connection

Alternative

connection

Current Flow

Bus Powered

Mode

Self-Sourced

3V3 TTL Mode

VCCIO

3V3OUT

VBUS

VCC

Figure 5.1 – Bus Powered Configuration

A bus powered configuration draws its power from the USB host/hub. The UMFT231XE is configured by

default to be in bus powered mode.

Figure 5.1 illustrates the UMFT231XE module in a typical USB bus powered design configuration. By

default VCCIO is connected to 3V3OUT, and VCC is connected to VBUS.

For a bus power configuration power is supplied from the USB VBUS:

+5V VBUS power is sourced from the USB bus and is connected to the FT231X power input (VCC)

+3.3V power is sourced from the FT231X‟s voltage regulator output and is connected to the FT231X IO

port‟s power input (VCCIO).

Interfacing the UMFT231XE module to a microcontroller (MCU), or other logic devices for bus powered

configuration is done the same way as a self-powered configuration (see Section 3), except it is possible

for the MCU or external device to take its power supply from the USB bus (either the 5V from the USB

pin, or 3.3V from the 3V3OUT pin).