FT240XS-U FTDI, FT240XS-U Datasheet - Page 26

• Manufacturer Part Number: FT240XS-U
• Description: USB Interface IC USB to Parallel FIFO IC SSOP-24
• Manufacturer: FTDI

Specifications of FT240XS-U

• Rohs: yes
• Tradename: X-Chip

7.2 Battery Charge Detection
A recent addition to the USB specification (
is to allow for additional charging profiles to be used for charging batteries in portable devices. These
charging profiles do not enumerate the USB port of the peripheral. The FT240X device will detect that a
USB compliant dedicated charging port (DCP) is connected. Once detected while in suspend mode a
battery charge detection signal is provided to allow external logic to switch to charging mode as opposed
to operation mode.
Figure 7.2 USB Battery Charging Detection (1 pin)
To use the FT240X with battery charging detection the CBUS pins must be reprogrammed to allow for the
BCD Charger output to switch the external charger circuitry on. The CBUS pins are configured in the
internal MTP memory with the free utility FTPROG. If the charging circuitry requires an active low signal
to enable it, the CBUS pin can be programmed to BCD Charger# as an alternative.
When connected to a USB compliant dedicated charging port (DCP, as opposed to a standard USB host)
the device USB signals will be shorted together and the device suspended. The BCD charger signal will
bring the LTC4053 out of suspend and allow battery charging to start. The charge current in the example
above is 1A as defined by the resistance on the PROG pin.
Alternatively the PWREN# And SLEEP pins may be used to control the LTC4053 such that a battery may
be charged from a standard host (low current) or from a dedicated charging port (high current). In such
a design as shown above the charge current would need to be limited to 0.4A to ensure that the USB
host power limit is not exceeded.
0.1uF
VBUS
GND
EEPROM Setting
X-Chip Pin
CBUS0
VBUS
CN USB
GND
SLD
4.7uF
VBUS
GND
D+
GND
D-
ID
0R
N.F.
1
2
3
4
5
Function
0.1uF
VBUS
GND
GND
BCD
10nF
600R/2A
VBUS
GND
27R
27R
0.1uF
Battery Charger Enable
3V3OUT
1
2
3
4
5
Battery Options
De-acticate Sleep
GND
Force Power Enable
CHRG
VCC
FAULT
TIMER
GND
DM
DP
3V3OUT
RESET#
GND
VBUS
LTC4053EDD
ACPR
SHDN
PROG
Copyright © 2013 Future Technology Devices International Limited
BAT
NTC
GND
X
3V3OUT
10
9
8
7
6
JUMPER-2mm
CBUS0
GND
2K2
FT240X
VBUS
4K32 1%
GND
http://www.usb.org/developers/devclass_docs/BCv1.2_011912.zip
1K5
BCD
NTC
JP1
SIP-3
BCD
NTC
0A when in sleep
0A when enumerated
0.1uF
0A when not enumerated and not in sleep
1A when connected to a dedicated charger port
VBUS
GND
VBATT
GND
GND
FT240X USB 8-BIT FIFO IC Datasheet
1R
1uF
3V3OUT
GND
GND
JP1
1-2
2-3
Document No.: FT_000626 Clearance No.:
NCT Available
0.1uF
NCT Enabled
NCT Disabled (Default)
TB3.5mm
1
+
-
NCT
Version 1.3
FTDI# 259
)
26