FAN5401 Fairchild Semiconductor, FAN5401 Datasheet - Page 24

• Manufacturer Part Number: FAN5401
• Description: The FAN5401 combines a highly integrated switched-mode charger, to minimize single-cell Lithium-ion (Li-ion) charging time from a USB power source, and a boost regulator to power a USB peripheral from the battery
• Manufacturer: Fairchild Semiconductor

Special Charger
FAN5403-05 Only
The FAN5403, FAN5404, and FAN5405 have additional
functionality to limit input current in case a current-limited
“special charger” is supplying VBUS. The FAN5403-05
slowly increases the charging current until either:

or

If V
FAN5403-05 charge with an input current that keeps
V
current, the SP bit (REG5[4]) is set.
Table 8. V
Safety Settings
FAN5403-FAN5405 Only
The FAN5403-05 contain a SAFETY register (REG6) that
prevents the values in OREG (REG2[7:2]) and IOCHARGE
(REG4[6:4]) from exceeding the values of the VSAFE and
ISAFE values.
After V
with its default value and may be written only before any
other register is written. After writing to any other register,
the SAFETY register is locked until V
The ISAFE (REG6[6:4]) and VSAFE (REG6[3:0]) registers
establish values that limit the maximum values of I
and V
write a value higher than VSAFE or ISAFE to OREG or
IOCHARGE, respectively; the VSAFE, ISAFE value appears
as the OREG, IOCHARGE register value, respectively.
© 2009 Fairchild Semiconductor Corporation
FAN5400 Family • Rev. 1.0.7
BUS
BUS
DEC
I
V
=V
INLIM
BUS
OREG
0
1
2
3
4
5
6
7
BAT
collapses to V
SP
=V
. When the V
or I
exceeds V
used by the control logic. If the host attempts to
SP
SP
OCHARGE
SP (REG5[2:0])
.
as Function of SP Bits (REG5[2:0])
BIN
000
001
010
011
100
101
110
111
is reached
SP
SHORT
SP
when the current is ramping up, the
control loop is limiting the charge
, the SAFETY register is loaded
HEX
00
01
02
03
04
05
06
07
BAT
falls below V
4.213
4.293
4.373
4.453
4.533
4.613
4.693
4.773
V
SP
SHORT
OCHARGE
.
24
Table 9. I
Bits (REG6[6:4])
Table 10. V
Bits (REG6[3:0])
Thermal Regulation and Protection
When the IC’s junction temperature reaches T
the charger reduces its output current to 550mA to prevent
overheating. If the temperature increases beyond T
charging is suspended, the FAULT bits are set to 101, and
STAT is pulsed HIGH. In Suspend Mode, all timers stop and the
state of the IC’s logic is preserved. Charging resumes at
programmed current after the die cools to about 120°C.
ISAFE (REG6[6:4])
DEC
DEC
VSAFE (REG6[3:0])
10
11
12
13
14
15
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
8
9
BIN
000
001
010
011
100
101
110
111
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
BIN
SAFE
SAFE
(I
HEX
OCHARGE
00
01
02
03
04
05
06
07
(V
HEX
0C
0D
00
00
01
02
03
04
05
06
07
08
09
0A
0B
0E
OREG
V
RSENSE
Limit) as Function of VSAFE
Limit) as Function of ISAFE
37.4
44.2
51.0
57.8
64.6
71.4
78.2
85.0
(REG2[7:2])
Max. OREG
100011
100100
100101
100110
100111
101000
101001
101010
101011
101100
101101
101110
101111
110000
110001
110010
(mV)
68m
www.fairchildsemi.com
1050
1150
1250
550
650
750
850
950
CF
I
SAFE
(about 120°C),
VOREG
(mA)
SHUTDOWN
100m
Max.
4.20
4.22
4.24
4.26
4.28
4.30
4.32
4.34
4.36
4.38
4.40
4.42
4.44
4.44
4.44
4.44
374
442
510
578
646
714
782
850
;